BIBLIOGRAPHY DONITA K. SIMONGO MAY 2007. ...
BIBLIOGRAPHY
DONITA K. SIMONGO MAY 2007. Growth, yield and dry matter partitioning
of potato genotypes under organic production at La Trinidad, Benguet. Benguet State
University, La Trinidad, Benguet.
Adviser: Belinda A. Tad-awan, PhD.
ABSTRACT
The study was conducted to determine the assimilates partitioning in potato
leaves, stems, roots, stolons and tubers during the different stages of development;
compare the efficiency of potato genotypes in terms of dry matter partitioning under
organic production, and determine the best time of harvesting potatoes for optimum dry
matter accumulation.
Seven potato genotypes grown under organic production were evaluated from
November 2006 to February 2007 at La Trinidad, Benguet, and the following were
found:
Genotypes 96-06, 13.1.1 and 5.19.2.2 were the best performers in terms of
survival, vigor, canopy cover, leaf area index, net assimilation rate and crop growth rate.
Assimilates partitioned into leaves, stems, roots, stolons and tubers at 45, 60, 75
and 90 DAP differed among genotypes and at different stages of development. Among
the plant organs, the roots and stolons had the highest dry matter contents in genotype
5.19.2.2 at 45, 60 and 75 DAP. However, dry matter contents of roots, stolons, tubers
and harvest index were not affected by tem
perature, rainfall, sunshine duration and light
intensities, for all the genotypes tested. Assimilates partitioned in tubers increased in
most of the genotypes at 75 DAP and decreased at 90 DAP except in genotypes 96-06
and 5.19.2.2.
Genotypes 5.19.2.2, 13.1.1 and 96-06 had the highest total yield of 4.57, 4.21 kg.
and 4.13 kg, respectively and computed marketable yields with respective means of 6.33,
5.46 and 5.92 tons/ha.
Genotype 573275 was highly resistant to leaf miner, cv. Ganza was intermediate
and 13.1.1, 5.19.2.2, 676089 and 96-06 were moderately resistant. Genotypes 5.19.2.2,
573275, 96-06 and 13.1.1 were resistant to late blight. Cultivar Granola was susceptible
to leaf miner and late blight.
Correlation analysis revealed positive significant correlations in: plant vigor with
light intensity in genotypes 96-06, 573275, and Ganza; dry matter content of leaves with
sunshine duration in Granola; dry matter content of stems with rainfall in genotype 96-06
and with maximum temperature in genotype 573275. Significant negative correlations
were observed in: canopy cover with maximum temperature in genotype 96-06; crop
growth rate with rainfall in genotypes 13.1.1 and 5.19.2.2; and leaf area index with
minimum temperature. No significant correlation was observed in temperature, relative
humidity, rainfall, sunshine duration and light intensity with dry matter content of roots,
stolons, tubers and harvest indices in all the genotypes.
Among the characters, positive correlations in canopy cover with harvest index
and in net assimilation rate with extra large tubers were observed. Highly significant
positive correlations were observed between net assimilation rate and crop growth rate.
While several of the data gathered are conclusive, it is recommended that further
studies maybe done to verify and confirm the results, particularly in other locations and
seasons.
ii
TABLE OF CONTENTS
PAGE
BIBLIOGRAPHY ......................................................................................................i
ABSTRACT ...............................................................................................................i
TABLE OF CONTENTS ...........................................................................................iii
I. INTRODUCTION ..................................................................................................1
Background of the Study .....................................................................................1
Significance of the Study .....................................................................................2
Objectives of the Study ........................................................................................4
Time and Place of Study ......................................................................................4
II. REVIEW OF LITERATURE ..............................................................................5
Potato Growth and Development ........................................................................5
Physiology of Potato ............................................................................................7
Environmental Requirements of Potato ...............................................................8
Dry Matter Accumulation ....................................................................................10
Organic Production ..............................................................................................12
Components of Organic Production.....................................................................13
III. MATERIALS AND METHODS .........................................................................16
Treatments ...........................................................................................................16
Planting Material Preparation .............................................................................16
The Farm .............................................................................................................16
Land Preparation .................................................................................................16
Organic Fertilizer Application and Plant .............................................................16
iii
Cultural Management Practices Employed .........................................................17
Experimental Design and Treatments ..................................................................17
Data Gathered .....................................................................................................18
Meteorological Data ............................................................................................18
Soil Analysis .......................................................................................................18
A. Growth Parameters ..................................................................................18
B. Yield and Yield Parameters ....................................................................22
C. Dry Matter Parameters ............................................................................22
D. Other Data ...............................................................................................25
Analysis of Data ..................................................................................................26
IV. RESULTS AND DISCUSSION ..........................................................................28
Meteorological
Data
............................................................................................28
Soil Analysis Before Planting and After Harvest ...............................................29
Plant
Survival
......................................................................................................30
Plant
Vigor
...........................................................................................................31
Canopy
Cover
.....................................................................................................32
Leaf Area Index ..................................................................................................34
Net Assimilation Rate (NAR) .............................................................................36
Crop Growth Rate ...............................................................................................37
Yield
Component
................................................................................................38
Dry Matter Content of Leaves, Stem, Roots (roots and stolons)
and Tubers at 45, 60, 75 and 90 DAP .................................................................47
Harvest Index at 45, 60, 70 and 90 DAP ............................................................55
iv
Leaf Miner Incidence at 45, 60, 70 and 90 DAP ................................................57
Late Blight Infection at 60 and 70 DAP .............................................................58
Correlation Analysis ...........................................................................................60
V. SUMMARY CONCLUSIONS AND RECOMMENDATIONS ..........................75
VI. LITERATURE CITED ........................................................................................82
VII. APPENDICES ...................................................................................................88
VIII. BIOGRAPHICAL SKETCH ...........................................................................105
v
1
INTRODUCTION
Background of the Study
The Potato, which is locally known as "patatas" or "papas", is one of the
major crops in the Philippine highlands.
Potatoes are grown mainly in the
cool, high altitude areas with well-distributed rainfall. The most suitable
elevation is between 1,500 to 2,500 masl (Haluschak, et al. 2001). It grows best
with temperatures ranging from 17 to 22oC and a soil temperature of 15 to 18 oC.
Average relative humidity requirement is 86% (Horton, 1987). Potatoes grow
well on a wide variety of soils. However, the ideal soil for potatoes is deep, well
drained, and friable.
In the Philippines, the major potato production area is concentrated in high
elevations with a temperature below 21 oC. This temperature is suitable for
growth and development of quality potato tubers. The major potato producing
municipalities of Benguet Province are Atok, Bakun, Buguias, Kabayan,
Kibungan and Mankayan and Bauko, Mountain Province (Gayao, et al. 1999).
The potato growing areas are usually in slightly rolling terrains and most of the
growing areas like Kibungan, Mankayan and Bauko Mountain Province are rain -
fed.
Potatoes are usually grown using conventional practices such as the use of
inorganic fertilizers and chemical pesticides. In the highlands, potatoes are one of
the most chemically sprayed crops. According to Ganga et al. (1995) and Gayao
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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et al. (1999), fungicide control constitutes about 12% of the total production cost
and this may go higher when susceptible cultivars are planted during rainy
seasons. Excessive amounts of potentially hazardous chemicals are clearly
undesirable in a foodstuff, particularly when it is widely consumed in
comparatively large quantities, and limits of concentration may be prescribed by
the FAO/WHO or by national legislation. Adequate monitoring of residues of
such chemicals is however, difficult (Burton 1989).
An alternative to conventional production is the use of organic products.
Organic potato production prohibits the use of synthetic chemicals, fertilizers,
pesticide, growth regulators, or genetically modified varieties. Delanoy, et al.
(2003) reported that the key to successful production of potatoes without the use
of synthetic pest control products is prevention and nutritional health.
Significance of the Study
Potatoes are an important crop in the Philippine highlands and farmers
grow this conventionally. The heavy use of fertilizers and pesticides cause
problems such as soil depletion and recurrence of new pest and diseases.
Growing potatoes organically may help the soil restore its nutrients and
recurrence of pest and diseases may be reduced, and predators used will not be
destroyed. As a result, there would be sound environment, safe potatoes for food,
and higher income for farmers.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
3
As in other production systems, organic potato production may require
varieties which, have efficient dry matter accumulation and resistant to pests and
diseases. Horton (1981) reported that dry matter production per hectare is a more
meaningful yardstick for comparing crops, regardless of their use for feed, starch,
or alcohol. Measures of edible energy and protein production per hectare are
more appropriate indicators of the nutritional yield of crops consumed by humans.
In terms of dry matter production per hectare, potatoes are among the most
productive crops grown in the developing countries. Production of dry matter,
edible protein, and monetary value may be used to measure the total production of
food crops.
Dry matter content varies considerably between varieties and is a strongly
inherited characteristic. Irrespective of cultural conditions that may affect dry
matter certain varieties are consistently high in dry matter, while others are
consistently low (Toolangi, 1996).
Growers must understand how to manipulate the growth of the leaf and
root system of the potato crop so that radiation interception may be maximized
and efficiency maintained. Tuber yield vary between seasons and between fields
within seasons. Photosynthesis could be described as the process of dry matter
production combined to produce glucose – sucrose – starch (Burke, 2003).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
4
Potato plant dry matter and partitioning patterns into various part of the plant
are important to fine tune management practices that optimize tuber production
(Kanzikwera, et al, 2001).
The Objectives of the Study were to:
1. Determine the assimilates partitioning in potato leaves, stems, roots,
stolons and tubers during the different stages of development;
2. Compare the efficiency of potato genotypes in terms of dry matter
partitioning under organic production; and
3. Determine the best time of harvesting potatoes for optimum dry matter
accumulation.
Time and Place of Study:
The field trial was conducted at Balili, La Trinidad from November 2006
to February 2007 and dry matter analysis of samples was done at the Semi-
temperate Vegetable Research Development Center, BSU laboratory from March
to April 2007.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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REVIEW OF LITERATURE
Growth and Development of Potato
The growth of a potato plant occurs in several stages: sprout development,
plant establishment, tuber initiation, tuber bulking and tuber maturation. Timing
of these growth stages varies depending upon environmental factors, such as
elevation and temperature, soil type, availability of moisture, cultivar selected and
geographic location (Dwelle and Love, 2006).
Achieving tuber maturity is complicated. As tubers grow, develop and
mature, a peak in dry matter production occurs. A minimum amount of sugar is
achieved shortly thereafter. This stage is considered physiological maturity and is
an indicator of when to start vine-kill and harvest (Dias, 2006). In cassava early
growth is characterized by development of shoot and fibrous root and assimilate
allocation changes from shoot to root with crop age (Akparobi, et. al. 2002).
Furthermore, Dar (1981) reported that the tuber of the potato is basically
considered as a part of its stems for food storage and reproduction. The so-called
root system of the plant is an extension of the stem. Stolons emerge in the
subterranean portion of the stem from the axis of scale leaves and they carry
adventitious root system and end in the tuber. Therefore, the potato tubers may be
regarded as enlarged stolons. Also, the skins of the tubers have several lenticels
and these are considered as the stomates of the tubers.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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Three periods can be distinguished in the potato's growth cycle: pre-
emergence/emergence, foliage growth, and tuber growth. Foliage growth and
tuber growth may overlap for a considerable time especially in late-maturing
varieties. Stems grow from the sprouts of the seed tuber. After stems emerge
from the soil, foliage and roots develop simultaneously and their growth is
correlated. Tubers generally start growing slowly about 2 to 4 weeks after
emergence and continue growing at a fairly steady rate (Horton, 1987).
Balaki (1981) stated that the leaf is responsible in the production of CHO
to be used for tuber growth. The same report put forward that the desired leaf
area index for potato ranged from 3 to 3.5 at the bulking stage.
Burke (2003) reported that tuber yield is determined by (i) the amount of
photosynthetically active radiation intercepted by the canopy (ii) the efficiency
with which this radiation is converted to dry matter and (iii) the proportion of
accumulated dry matter partitioned to the tubers. Each of the forgoing steps may
be influenced by the grower and an understanding of their contribution to tuber
yield may help explain variation in yield observed between varieties, between
growing seasons and between fields within a growing season.
According to Dias (2006) achieving tuber maturity is complicated. As
tuber grows, develop and mature, a peak in dry matter production occurs. A
minimum amount of sugar is achieved shortly thereafter. This is important
because high dry matter and low sugar content are important for processing. This
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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stage is considered physiological maturity and is an indicator of when to start
vine-kill and harvest.
Physiology of the Potato Crop
Burton (1989) reported that physiological behavior is used as an aid in
classification rather than in identification, although the time when sprouting starts,
and the rate of sprout growth, though varying from year to year and with the
origin of the tubers, may be used to distinguish between the tubers of some
varieties. The response to photoperiod may vary considerably, and is a major
point of difference between S. tuberosum sub sp. tuberosum and S. tuberosum sub
sp. Andigena. It may underlie a number of physiological differences such as time
of maturity.
The economic yield of any crop is a function of the amount of light energy
absorbed by the green foliage, the efficiency of the foliage to use the energy
captured for biomass production, and the partitioning of the crop biomass to the
harvested plant part. Because potatoes has one of the highest harvest indices of
major crops and there may be little potential for significant shifts in total biomass
accumulation, genotypes with potential for significant shifts in total biomass
accumulation, genotypes with superior net photosynthesis will likely be needed
for further yield improvement Flyn et. al. (1998) as cited by Schittenhelm et. al.
(2004).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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Environmental Requirements of Potatoes
The potato crop is grown mainly in the cool, high altitude areas with well-
distributed rainfall. The most suitable elevation is between 1,500 meters to 2,500
meters above sea level (Haluschak, et. al. 2001). The potato grows best with
temperatures ranging from 17 to 22oC and with average relative humidity
requirement of 86%. Soil temperatures of 15 to 18 oC appear to be the most
favorable for common potato varieties (Horton, 1987).
Burton (1966) reported that temperature influences the rate of both
photosynthesis and respiration, and the net effect of an increase in temperature
might range from increase to a marked decrease in yield of dry matter. The same
report further said that an optimum temperature for tuber formation and growth in
most potato varieties is about 15oC to 20oC. Engel and Raeuber (1981) likewise
found that the maximum temperature during the day is 20oC and 14oC during the
night, and Bodlaender (1963) stated that the potato requires different temperature
regimes for different stages of growth. High temperature appears to stimulate
plant growth but is unfavorable for leaf expansion. The maximum leaf weight
may be produced at 12oC to 14oC. Furthermore Hartmann et. al. as cited by
Chong et. al (2000) reported that temperature is the single most important factor
in the regulation of the timing of germination, because of its role in dormancy
control and/or release, or climatic adaptation.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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It has been cited that potatoes are affected by the differences in
temperature, Anon (2006). It was stated by the same source that tuberization
occurs earlier at lower temperatures, approximately 3 to 5 weeks earlier than
those in longer, warmer days. The optimal temperature for tuberization is 55oF,
the process decreases above 70oF and with certain cultivars, may stop at 85oF was
also cited by the same source. Furthermore Winkler (1969) reported that, in
general optimum conditions for high potato yields are average leaf temperature of
17 to 18 oC and average maximum air temperature of 20 to 23 oC. Likewise
Bodlaender (1963) stated that optimum temperature for stem elongation was
found to be 18 oC.
As reported by Yamachugi (1964) the soil temperature can affect tuber
development. He found that stem emergence was rapid at 21oC to 24oC and the
optimum soil temperature for tuber formation was between 15oC to 24oC. At
26oC to 29oC, tubers developed are misshapen and often, several tubers formed
single stolons. Malik and Dwelle stated further that plants accumulated more total
dry matter under cool soil (15 and 19 oC) temperatures than under hot soil (30 oC)
conditions. Soil properties, Toolangi (1996) revealed that soil pH is generally not
regarded as having a direct effect on dry matter but can affect total dry matter per
hectare by its effect on yield.
High evaporative demand caused by low relative humidity, high solar
radiation, and/or high wind speed can also reduce photosynthesis. Prolonged
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
10
periods with overcast skies can reduce light intensity to levels below that required
for maximum dry matter production (Stark et. al. 2003). Likewise Beukema and
Vander Zaag (1979) stated that light used for assimilation depends on the light
available (light intensity and daylength) and the light intensity intercepted by the
green leaves.
The optimal photoperiod for potato yields depends upon temperature and
cultivar, such that Andigena cultivars fail to tuberize unless they have received
short days (Simmonds 1964). Furthermore Marique (undated), reported that the
shorter the photoperiod, the greater the percentage of plant biomass that is
partitioned to tuberosum cultivars, especially those that are early maturing, which
may perform poorly under cool tropical conditions because tuber induction is
excessively strong. The same report claims that the result of excessively strong
induction is that haulm and root growth are so restricted by the strong partitioning
of dry matter to tubers that the leaf area is too small to support good tuber yields.
Cooper and Fox (1996) stated that the relative performance of genotypes
changes across environments, thus most breeding programs conduct multi-
environment trials to evaluate genotypic adaptation over a sample of
environments from the target population.
Dry Matter Accumulation
According to Horton (1987) the length of a potato variety's growth cycle is
influenced by environmental conditions, so that a variety that is late under one set
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
11
of growing conditions can be early under another. Likewise DPI (2006) and
Toolangi (1996) reported that dry matter content varies considerably between
varieties and is a strongly inherited characteristic. As reported, irrespective of
cultural condition that can affect dry matter certain varieties are consistently high
in dry matter, while others are consistently low.
According to Kanzikwera et. al. (2001) potato plant dry matter and
partitioning pattern into various parts of the plant are important to fine tune
management practices that optimize tuber production. The same source stated that
dry matter production per hectare is a more meaningful yardstick for comparing
crops, regardless of their use for feed, starch, or alcohol, and measures of edible
energy and protein production per hectare are more appropriate indicators of the
nutritional yield of crops consumed by humans. In terms of dry matter production
per hectare, potatoes are among the most productive crops grown in the
developing countries; and production of dry matter, edible protein, and monetary
value can be used to measure the total production of food crops (Horton, 1987).
Two useful terms used to describe partitioning of dry matter by plants are
biological yield and economic yield. The term biological yield was proposed by
Nichiporovich (1960) to represent the total dry matter accumulation of a plant's
system. Economic yield and agricultural yield have been used to refer to the
volume or weight of those plant organs that constitute the product of economic or
agricultural value. The proportion of biological yield represented by economic
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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yield has been called harvest index, the coefficient of effectiveness, or the
migration coefficient (Gardner, et al, 1985).
Initially, dry matter is divided between stems and leaves (growth stage II).
In the second phase, which starts at tuber initiation, an increasing amount of
accumulated dry matter is allocated to the tubers and decreasing fraction to leaves
(growth stages III and IV). In the third phase all assimilates are allocated to the
tubers (growth stage V) (Pereira and Shock, 2008).
Organic Production
Organic production is designed to work with natural processes to conserve
resources, encourage self-regulation through diversity, and minimize waste and
environmental impact, while preserving farm profitability. Such systems aim to
produce food that is nutritious and uncontaminated with substances that could
harm human health (Edward-Jones and Howells, 2000).
Organically grown crops produce consistently tests product higher than
non-organically grown foods for vitamins, minerals, and other micronutrients, as
well as showing much smaller amounts of nitrates, heavy metals and other
contaminants. One of the main reasons for this nutritional discrepancy is that
organic soil is much richer in minerals and micronutrients than non-organic soil
(Anon, 2005).
The various source further stated that plants grown on healthy soil are less
susceptible to pests and so; the need for pest eradication is reduced. Chemical-
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
13
based agriculture however, begins with soil which is already nutrient depleted;
that plants grown on depleted soil are weaker and more prone to disease and
pests, so more chemicals are needed every year.
An ample supply of decaying organic matter helps to keep the soil loose
and mellow and thus reduces soil compaction. Potato tubers develop and maintain
normal shape better in loose, well-aerated soils. Organic matter facilitates plowing
and cultivating; it enables roots of potato plants to penetrate the soil more readily,
and it improves water retention; it provides food energy for the growth of
desirable soil micro-organisms and supplies plant nutrients (Anon, 2006).
Components of Organic Production
Use of Organic Fertilizers
Horton (1987) reported that organic fertilizer improves the soil structure
and increase the moisture retention capacity. Davis and Wilson (2002) likewise
stated that the application of organic soil amendments increase soil organic matter
content and offer many benefits such as: it improves soil aeration, root infiltration
and both water and nutrient holding capacities and act as organic fertilizer, and
pants that absorb the nutrients in the soil can tolerate damage caused by soil
pathogens.
The importance of organic matter are: source of nutrients; improves CEC
of the soil-high CEC protects available and exchangeable cation from leaching;
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
14
source of humus; decomposition products such as organic acids help dissolve
minerals and insoluble phosphates and it improves water-holding porosity,
aeration and aggregation of the soil, thus improving soil environment for normal
root growth (Balaki, 1981).
On the other hand, according to the Philippine Council for Agricultural
Resources Research and Development (PCARRD, 1982), the literal application of
soil organic fertilizers supply an amount of nutrient requirements of the
granulation, and easy root penetration. On the other hand, Korva and Varis
(1990); Haraldsen et al. (2000) as cited by Delden (2001) reported that smaller
arable crop yields in organic farming systems compared with those from
conventional practices have been attributed to a mismatch between N supply and
demand. Thus, in organic farming, the limited amounts of available N require
more effective distribution among the various crops optimizes farm results.
It has been reported that: Potash and phosphorous will need to be provided
in the form of composted farmyard manure; that if this is not available from an
organic source then it can be brought in and composted on the farm for a period of
three months prior to use. And that depending on the natural fertility of the soil
manure is generally spread at a rate of 30 - 35 t/ha (Western Potato Council,
2003).
Diversity in crop production. The farm should have sufficient crop
diversity in time and/or space that takes into account pressures from insect,
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
15
weeds, diseases and other pests while maintaining or increasing soil organic
matter, soil fertility, microbial activity and general soil health (Anon, 2003).
Choice of crops and varieties. Species and varieties cultivated should, as
far as possible, be adapted to the soil and climatic conditions and should be
resistant to pests and diseases; and that all seeds and plant materials used should
be from certified organic produce or from the same farm (Anon, 2003).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
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MATERIALS AND METHODS
Treatments
Seven potato genotypes selected from previous evaluations under organic
production were grown at Balili La Trinidad with an elevation of 1,300 m asl.
Planting Material Preparation
The planting materials from the seven potato genotypes were secured from
Cabutotan, Bakun where organic production practices were followed.
The Farm
The land used was transitioned to organic production four years ago.
Rotations of crops such as beans, potato, and beans were practiced. The land was
fallowed for at least three months before the cropping season from March to
October. Corn was planted on the borders of the farm to serve as barrier while
marigold was planted in between beds to serve as pest repellants.
Land Preparation
The area was first cleared of weeds and prepared using a tractor. Plots
were prepared measuring 1m wide x 5m long.
Organic Fertilizer Application and Planting
Compost at a rate of 10kg/5m2 was evenly incorporated with the soil one
month before planting.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
17
Sprouted tuberlets of the different potato genotypes and cultivars were
used as planting materials. Forty seed tubers of each genotype and culitvar were
planted at a distance of 30 cm between hills and 20 cm between rows.
Cultural Management Practices Employed
Irrigation was done twice a week using a water pump with hose. Pests and
diseases were controlled through the integration of mixed cropping, planting of
repellant crops such as marigold, use of yellow traps and application of bio-
fungicide (Bacillus subtilis).
Experimental Design and Treatments
The experiment was laid out following the randomized complete block
design (RCBD) with three replications. Each block was subdivided into 7 plots
measuring 1m x 5m. The use of the term cultivar (cultivated variety) or cv. In
short is appropriate, technologically.
Treatment Genotype
Code/Cultivar Source
V1
13.1.1
CIP, Peru
V2
96-06
CIP, Peru
V3 573275
CIP,
Peru
V4
5.19.2.2
Philippines
V5 676089
CIP,
Peru
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
18
V6
Ganza
CIP, Peru
V7
Granola
Germany
Data Gathered:
Destructive sampling was done at 30, 45, 60, 75 days after planting (DAP)
to obtain the dry mass of the leaves, stems, roots, stolons and tubers. Plate 1
shows the different genotypes at 60 DAP.
Meteorological Data
Meteorological data such as air temperature, relative humidity, rainfall
amount and sunshine duration was taken at the BSU-PAG-ASA records. Light
intensity was taken weekly using the light intensity meter.
Soil Analysis
Soil samples were obtained before and after planting and brought to the
Soils Laboratory at Pacdal, Baguio City for analysis.
A. Growth Parameters
1. Percent Survival. Percent survival was taken at 30 DAP by counting the
number of plants that survived and computed using the formula:
No of plants that survived
% Survival = _____________________ x 100
Total no. of plants planted
Growth, yield and dry matter partitioning of potato genotypes under organic
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2. Plant Vigor. This was recorded at 30, 45, and 60 (DAP) using the
following rating scale by Palomar and Sanico, 1994.
Scale
Description
Reaction
5
Plants are strong with robust stems and Highly vigorous
leaves; light to dark green in color
4
Plants are moderately strong with robust Moderately
stems and leaves; light green in color.
vigorous
3
Plants are better than less vigorous
Vigorous
2
Plants are weak with few thin stems and Less vigorous
leaves; pale
1
Plants are weak with few stems and leaves; Poor vigor
very pale.
3. Canopy Cover. A hand - made grid with a wooden frame and a threaded wire
was used. A marker was placed at the center of four sample plants at random per
replication, and then the grid was placed against the marker. Canopy cover was
taken at 30, 45, 60 and 75 DAP.
4. Leaf Area Index (LAI). The leaf area of two sample plants was collected at
45, 60 and 75 dap. Two green leaves from the lower, middle and upper parts
were considered from the sample plants using the Tracing Technique method by
Saupe (2006). This compares a paper replica of the surface to be measured to a
standard of known area.
Growth, yield and dry matter partitioning of potato genotypes under organic
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Leaf area (mm2) = weight of leaf tracing (g) x conversion factor (mm2 gm-1)
Leaf area (mm2)
Leaf area Index (LAI) = _________________
Ground area (mm2)
Note: The leaf area was determined by multiplying the leaf area per leaf
to the total number of leaves per plant.
5. Net Assimilation Rate (NAR). This is the dry matter accumulation rate per
unit of leaf area per unit of time and was taken following the formula by Fitter
and Hay, 1981:
NAR g / m-2/d = lnW2 – lnW1 x (La)
T2 – T1
Where:
L
A = Leaf area
W = Weight
T = Time (days)
6. Crop Growth Rate. This was computed following the formula by Gardner,
1985:
CGR = (NAR) x (LAI)
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
21
13.1.1
96-06
A B
573275
5.19.2.2
C
D
676089
Ganza
Granola
G E F
Plate 1. The genotypes and cultivars sampled at 60 DAP.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
22
B. Yield and Yield Components
1. Tuber Yield Parameters
a. Number and weight of marketable tubers per plot (kg). All tubers
of marketable quality (small, medium, extra and large) were
counted and weighed.
b. Number and weight of non-marketable tubers per plot (kg). These
were the tubers that are malformed, damaged by insects and
diseases and those with more than 10% greening.
c. Total yield per plot. This is the sum of weight of marketable and
non-marketable tubers per plot.
d. Computed yield (t/ha). This was computed following the formula.
Total marketable yield/plot x 10,000 m2
Yield (kg) = ___________________________________
5m2
Yield (tons/ha) = Yield (kg)
1000
C. Dry Matter Parameters
At 45, 60, and 75 DAP, destructive sampling was done to determine the
dry matter partitioned in the leaves, stems, roots, stolons and tubers. Samples of
the leaves, stems, roots, stolons and tubers were separated and weighed, packed in
brown paper bag labeled properly and placed in the oven just after arriving from
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
23
the field to the laboratory. The oven was set at 80oC. After 56 hours the dry
weight was taken.
1. % Dry Matter Content of Leaves, Stems, Roots, Stolons and Tubers.
Plate 2 presents the procedure in determining the dry matter of the
different genotypes and cultivars.
Dry matter content of the leaves, stems, roots, stolons and tubers were
obtained by the following formula:
%DMC = 100 – MC
Where: %MC = Fresh weight – Oven dry weight x 100
Fresh weight
2. Harvest Index (%)
Harvest Index is the ratio of the economic yield to biological yield, which
is expressed as:
% HI = TDW x 100
LDW + SDW + RSDW
Where:
TDW = Tuber dry weight
RSDW = root and stolons dry weight
LDW = leaf dry weight
SDW = Stem dry weight
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
24
Separation of leaves, stems, roots, Slicing of potato tubers into cubes
stolons and tubers
Weighing of potato tubers Weighing of potato leaves
Weighing of potato stems Oven drying of the leaves, stems,
roots, stolons and tubers
Plate 2. Procedure in dry matter determination of the different genotypes and
cultivars.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
25
D. Other Data
1. Leaf Miner Incidence
The appearance of insect pest was observed during the growth stage of
the plant using the following scale (CIP, 2001):
SCALE DESCRIPTION
1 No apparent injury
2
Injury confined to youngest leaves
3
Some older leaves exhibiting injury
4
Over 50 % of the leaves injured
5
Over 90 % of the leaves injured
2. Late Blight Infection
Late blight was observed during the growth stage of the plant at 60 and 75
DAP using the CIP rating scale (Henfling, 1987):
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
26
CIP
Blight (%)
scale
value
Mean limit
Symptoms
1
0
No late blight observable
2
2.5
Traces -< 5
Late blight present. Maximum 10 lesions per plant
3
10
5 -< 15
Plants look healthy, but lesions are easily seen at
closer distance. Maximum foliage area affected by
lesions or destroyed corresponds to no more than
20 leaflets.
4
25
15 -< 35
Late blight easily seen on most plants. About 25%
of foliages is covered with lesions or destroyed.
5
50
35 -< 65
Plot looks green; however, all plants are affected.
Lower leaves are dead. About half the foliage area
is destroyed.
6
75
65 -< 85
Plots look green with brown flecks. About 75% of
each plant is affected. Leaves of the lower half of
plants are destroyed.
7
90
85 -< 95
Plot neither predominantly green nor brown. Only
top leaves are green. Many stems have large
lesions.
8
97.5
95 -< 100
Plot is brown-colored. A few top leaves still have
some green areas. Most stems have lesions or are
dead.
9
100
All leaves and stems dead.
The description of symptoms is based on plants with 4 stems and 10 to 12 leaves
per stem.
Analysis of Data
The data was analyzed through analysis of variance in RCBD except for
leaf miner and late blight. Significance among treatment means was analyzed
using the Duncan's multiple Range Test (DMRT). Correlation analysis was also
done.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
27
According to Amid (2005), the degree of relationship between two
variables can be measured using the Pearson product moment correlation
coefficient (R) which characterizes the independence of X and Y. The coefficient
R is a parameter, which can be estimated from sample data using the formula:
NΣxy – (Σx)( Σy)
R = _______________________________
[n Σx2 – (Σx)2] [n (Σy ) – (Σy)2]
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
28
RESULTS AND DISCUSSION
Meteorological Data
The minimum and maximum air temperature during the study period
ranged from 12.6 to 15.6 oC and 23.5 to 24.2 oC, respectively while relative
humidity ranged from 77 to 80 % (Table 1). Horton (1987) stressed that potato
grows best with temperature ranging from 17 to 22 oC and with an average
relative humidity of 86%. Temperature and relative humidity during the conduct
of the study were observed to be appropriate for potato production. A very little
rainfall of 2.5, 2.4 and 0.05 mm was recorded in November, December and
January, respectively. Sunshine duration in the month of November, December
and January was low ranging from 386.6 to 381.4 mm as compared to the
sunshine duration in February, which is 521.6 mm (Table 1). Light intensity was
observed to be low from November to January with December having the lowest
light intensity of 45.1 Klux while February had the highest light intensity with
76.4 Klux.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
29
Table 1. Meteorological data from November 2006 to February 2007.
AIR TEMP. (oC) RELATIVE RAIN-
SUNSHINE
LIGHT
HUMIDITY
FALL
DURATION INTENS-
MONTH
MIN
MAX
(%)
AMT.
(mm)
ITY*
(mm)
(Klux)
Nov.
15.2
23.5
80
2.5
381.4
57.2
Dec.
15.6
24.2
78
2.4
387.0
45.1
Jan.
13.9
23.9
77
0.03
386.6
58.9
Feb.
12.6
23.6
77
0
521.6
76.4
Soil Analysis Before Planting and After Harvesting
Results of the analysis revealed that soil pH before planting was 6.72 and
slightly decreased to 6.31 after harvest (Table 2). Organic matter, phosphorus,
potassium and nitrogen increased. The increase in the organic matter,
phosphorus, potassium and nitrogen was probably due to the application of
compost hilled-up at 30 DAP. Smilde (undated) reported that the decomposing
humus is a slow-release source of nutrients to plants and carbon to
microorganisms. The same report stated that crops with shallow root system like
potatoes might absorb only the partially released nutrients from the fertilizer
applied. Furthermore, Colting (1981) pointed out the following: that organic
residues with narrow C:N ratio (i. e. legumes), take longer time to decompose.
That, long term benefits are derived from fully decomposed residues with wide
C:N ratio. That organic matter with C:N ratio higher than 30 usually immobilizes
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
30
N at the earlier stage of decomposition. Examples of C:N ratios used in the
Colting report were: cereal straw (C:N ratio = 80); green manure (C:N ratio = 20);
stable organic matter (C:N ratio = 110-120).
Table 2. Soil analysis before planting and after harvesting.
SOIL PROPERTY
BEFORE PLANTING
AFTER HARVEST
PH
6.72
6.31
Organic matter (%)
2.50
4.50
Nitrogen
0.13
0.23
Phosphorus (ppm)
90
140
Potassium (ppm)
312
341
Plant Survival
Table 3 shows significant differences on the percent plant survival among
the seven genotypes evaluated at 30 DAP. Genotype 13.1.1 significantly had the
highest plant survival of 98 % followed by 5.19.2.2 with plant survival of 97 %.
The rest of the genotypes had plant survivals ranging from 30 to 85 %. The
variability of the plant survival rate as found in the study was mainly affected by
their sprouting ability as exhibited by their genetic characteristics affected by the
environmental factors prevailing during the conduct of the trial.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
31
Table 3. Percent survival of seven potato genotypes grown at La Trinidad
under organic production.
GENOTYPE PLANT
SURVIVAL
(%)
13.1.1
98a
96-06
85a
573275
30b
5.19.2.2
97a
676089
75a
GANZA
74a
GRANOLA
50b
CV (%)
17.73
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Plant Vigor
The plant vigor at 30, 45, and 60 DAP of the seven genotypes is shown in
Table 4. Genotypes 13.1.1 and 5.19.2.2 significantly exhibited highly vigorous
growth at 30, 45, and 60 DAP. Genotype 573275 had moderate vigor at 30 DAP
but recovered at 45 and 60 DAP. Cultivar Granola had moderate vigor rates at 30
and 45 DAP and less vigorous at 60 DAP. The variation on plant vigor among
the genotypes evaluated may be due to their genetic characteristics as affected by
the environmental factor prevailing during the study period.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
32
Table 4. Plant vigor of seven potato genotypes Grown at La Trinidad under
organic production.
GENOTYPE
PLANT VIGOR
30 DAP
45 DAP
60 DAP
13.1.1
5a
5a
5a
96-06
4b
5a
5a
573275
3c
4b
4b
5.19.2.2
5a
5a
5a
676089
4b
4b
5a
GANZA
4b
5a
5a
GRANOLA
3c
3c
2c
CV (%)
8.82
6.50
6.50
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Rating Scale:
5 = Highly vigorous
4 = Moderately vigorous
3 = Vigorous
2 = Less vigorous
1 = Poor vigor
Canopy Cover
Significant differences on the canopy cover at 30, 45, 60 and 75 DAP was
observed among the seven genotypes (Figure 1).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
33
All the genotypes showed an increasing canopy cover from 30 to 60 DAP
but decreased at 75 DAP. Genotype 96-06 significantly had the highest canopy
cover followed by genotypes 5.19.2.2 and 13.1.1. At 60 DAP genotype 5.19.2.2
significantly had the highest canopy cover followed by that of 96-06 and 13.1.1.
Cultivar Granola had the lowest canopy cover at 30 up to 60 DAP. The canopy
cover differed among genotypes, which may be attributed by their inherent
characteristics. Amer and Hatfield (2004) reported that the peak of leaf area is
chiefly influenced by variety, fertilizer and planting date.
One of the environmental factors that affected the vegetative growth may
be light intensity. The light intensity was low from November to February
ranging from 57.2 to 58.9 Klux and increased to 76.4 Klux from the month of
January. This conforms with the report of Dar (1981) that at lower light
intensities, haulm growth is stimulated and tuber growth is delayed. Furthermore,
the same author put forward that some of the genotypes started to senesce while
others was early attacked with leaf miner, thus the lower leaves fall of resulting to
lower canopy. Amer and Hatfield (2004) also reported that leaf area decreased
during the maturity stage because of senescing leaves in the lower part of the
canopy.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
34
60
a
a
a
50
a
a
13.1.1
ab ab
a
a
40
96-06
a
ab
a
573275
a
a
a
b
30
ab
b
a
5.19.2.2
bc
676089
20
b
Canopy Cover
bc
Ganza
c
cd
10
Granola
c
c
d
0
c
30
45
60
75
Days ater planting
Figure 1. Canopy cover of seven potato genotypes grown at La Trinidad under
organic production.
Leaf Area Index
All the genotypes had increased in their leaf area indices at 60 DAP but at
75 DAP, some genotypes of which had decreased while the others increased
(Figure 2).
Genotype 5.19.2.2 significantly had the highest leaf area index at 45 DAP
followed by genotypes 96-06 and 13.1.1 while genotypes 573275 and cv. Granola
had the lowest leaf area indices. At 65 DAP all the genotypes increased in their
leaf area indices with genotype 5.19.2.2 showing the significantly highest
followed by 96-06 and 697089, while cv. Granola had the lowest leaf area index.
Genotypes 5.19.2.2, 676089, 573275 and cv. Ganza showed an increasing
leaf area indices at 75 DAP while genotypes 96-06, 13.1.1 and cv. Granola had a
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
35
decreased leaf area index at 75 DAP (Figure 2). The decrease in the leaf area
indices was possibly due to the falling down of leaves. The falling of leaves
during the study was due to the leaf miner infestation and senescence. Amer and
Hatfield, (2004) reported that leaf area decreased at maturity stage because of
senescing leaves in the lower part of the canopy. However in the case of cv.
Granola decrease in leaf area index at 75 DAP was observe to be caused by leaf
miner infestation and late blight infection.
Significant variability of leaf area index among the genotypes evaluated
may be attributed to their genetic characteristics as influenced by these factors and
other factors such as insect and disease infection.
5
a
a
4.5
a
ab
4
13.1.1
b
3.5
96-06
a
bc
3
bc
573275
cd
2.5
b
ab
5.19.2.2
2
abc
de
676089
1.5
c
Ganza
Leaf Area Index
ef
bcd
1
bcd
Granola
cd
0.5
f
d
0
d
45
60
75
Days After Planting
Figure 2. Leaf area index of seven potato genotypes grown at La
Trinidad under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
36
Net Assimilation Rate (NAR)
Net assimilation rate or the dry matter accumulation rate per unit leaf area
is one of the useful parameters on growth analysis, which influence the increase in
plant weight per unit area of assimilatory tissue (usually leaf area: AL) per unit of
time (Fitter and Hay, 1981).
Net assimilation rate of the seven genotypes at 45, 60 and 75 DAP are
presented in Figure 3. On the other hand, results showed no significant
differences among the genotypes on their net assimilation rate at 45 and 75 DAP.
Also, statistical analyses showed significant differences on the net assimilation
rates of all the genotypes tested at 60 DAP.
All the genotypes showed an increasing net assimilation rate at 60 DAP
except for cultivar Granola. Genotype 5.19.2.2 significantly had the highest net
assimilation rate at 45 up to 75 DAP. Genotypes 676089 had the second highest
net assimilation rate at 60 DAP followed by genotypes 96-06 and cv. Ganza. At
75 DAP, it was observed that genotypes 676089, 96-06, 573275 and 13.1.1
increased in their net assimilation rate except for cultivars Ganza and Granola.
Results showed that genotypes 676089, 96-06, 573275 and 13.1.1 had an
increased dry weight accumulation per unit area of assimilatory per unit of time.
The increase in the net assimilates may be due to the biological dry biomass or
economic dry biomass of genotypes. The increased or decreased net assimilation
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
37
rate among the genotypes tested may have been affected mainly by their inherent
characteristic.
16.00
14.00
a
12.00
13.1.1
96-06
10.00
b
573275
8.00
b
5.19.2.2
b
676089
6.00
bc
Ganza
bc
4.00
Net Assimilation Rate
Granola
2.00
c
0.00
45
60
75
Days After Planting
Figure 3. Net assimilation rate of seven potato genotypes grown at La
Trinidad under organic production.
Crop Growth Rate
The crop growth rates of different genotypes evaluated during the study
are shown in Figure 4. Crop growth rate is the dry matter accumulation percent of
land area per unit of time (Gardner et. al. 1985).
Figure 4 showed an increasing crop growth rates from all the genotypes at
60 DAP except in cv. Granola. Genotype 5.19.2.2 significantly had the highest
crop growth rate at 45 to 65 DAP while cv. Granola was the lowest. At 75 DAP
genotype 676089 significantly increased in its growth rate while genotypes
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
38
573275 and cv. Ganza had little increase. On the other hand, Genotypes 5.19.2.2,
96-06 and 13.1.1 showed decreasing growth rates, which indicate that these
genotypes had attained their maturity period. On the other hand, genotypes
676089 and 573275 were still accumulating dry matter, which indicate that these
genotypes had longer period of maturity.
70.00
60.00
a
13.1.1
50.00
a
96-06
573275
40.00
ab
5.19.2.2
a
30.00
676089
b
bc
bc
20.00
Ganza
Crop Growth Rate
bc
b
bc
Granola
bc bc
c
10.00
bc bc
c
c
c
c
0.00
c
c
45
60
75
Days After Planting
Figure 4. Crop growth rate of seven potato genotypes grown at
La Trinidad under organic production.
Yield Components
At harvest, the yield was classified according to sizes as prescribed. The
classified tubers were counted, weighed and recorded. Extra large tubers had an
average weight of 100 to 150 g, large tubers had an average weight of 50 to 99 g,
medium tubers had an average weight of 26 to 49 g, small tuber had an average
weight of 10 to 25 g and marble tubers had an average weight of 3 to 9 g. Non-
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
39
marketable tubers are the smallest size, rotten, and had more than 10% damage
and greening.
Number of Marketable Tubers According to Size/Plot
Extra Large Tubers. Table 5 shows the number of marketable tubers
according to size per plot of the seven genotypes evaluated. Significant
differences were observed among the treatments on the number of extra large
tubers. Genotype 13.1.1 significantly produced the most tubers while cv. Granola
produced no extra large tubers. The rest of the extra large tubers ranged from 4 to
7.
Large Tubers. The genotypes significantly differed in their mean number
of large tubers (Table 5). Genotype 13.1.1 significantly produced the most tubers
32. Cultivars Ganza and Granola, produced 6 and 0 tubers, respectively. The rest
of the genotypes produced 11 to 14 large tubers.
Medium Tubers. No significant differences were observed among the
treatment means on the number of medium tubers (Table 5). Genotype 13.1.1
produced the highest number of medium tubers with 41 while cv. Granola had no
medium tubers (Table 5).
Small Tubers. The number of small tubers was significantly different
among the seven genotypes evaluated (Table 5). Genotype 13.1.1 significantly
produced the highest number of small tubers (26) while cultivar Granola had the
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
40
least (5). The rest of the entries produced numbers of small tubers ranging from 8
to 17.
Non-marketable Tubers
Table 5 shows the number of non-marketable tubers of the different
genotypes evaluated. Among the genotypes evaluated, no significant differences
were noted on the number of non-marketable tubers.
Table 5. Number of marketable (extra large, large, medium, small and marble)
and non Marketable tubers of seven potato genotypes grown at La
Trinidad under organic production.
NUMBER OF
GENOTYPE
NUMBER OF MARKETABLE TUBERS
NON-
Extra- Large Medium Small Marble
MARKETABLE
large
TUBERS
13.1.1
10a
32a
41
26a
26
19
96-06
7ab
14b
29
17ab
19
31
573275
4bc
11bc
25
8b
7
18
5.19.2.2
7ab
14b
30
14b
23
17
676089
4bc
11bc
28
11b
12
22
GANZA
6ab
12bc
17
14b
15
21
GRANOLA
0c
0c
0
5b
4
11
CV (%)
26.32 20.95
27.28
17.07
25.66
28.45
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
41
Weight of Marketable Tubers According to Size/Plot
Extra Large Tubers. Table 6 shows the weight of tubers. The genotypes
evaluated significantly differed in their mean weights of extra large tubers.
Genotype 5.19.2.2 significantly outranked the cultivars Ganza and Granola with
weights of 0.83, 0.47 and 0 kg, respectively. The rest of the genotypes produced
weights ranging from 0.32 to 0.65 kg.
Large Tubers. Significant differences among treatment means of the
genotypes evaluated produced large tuber weights (Table 6). Genotype 13.1.1
significantly had the highest tuber weight of 1.52 kg followed by genotype
5.19.2.2 (1.05 kg). The cultivar Granola had no large tuber. The rest of the
genotypes had weights ranging from 0.63 to 0.84 kg.
Medium Tubers. Statistical analysis showed significant differences among
the medium mean weights of the seven genotypes (Table 6). Genotype 5.19.2.2
significantly had the highest mean weight of 1.39 followed by 96-06, 676089 and
13.1.1 with mean weights of 1.29, 1.27 and 1.22 kg, respectively. The least was
produced by genotype 573275 with mean weight of 0.59 kg while cv. Granola had
no medium tubers.
Small Tubers. Table 6 showed no significant differences among the treatment
means of small weight tubers. The tubers weighed from 0.04 to 1.04 kg.
Marble Tubers. Mean weights of marble tubers revealed no significant
differences among treatment means of the genotypes evaluated (Table 6).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
42
Non-marketable Tubers
Table 6 shows the weight of non-marketable tubers of the different
genotypes evaluated. Among the genotypes evaluated, no significant differences
were noted on the weight of non-marketable tubers.
Table 6. Weight of marketable (extra large, large, medium, small and marble)
and non-marketable tubers of seven potato genotypes grown at
La Trinidad under organic production.
WEIGHT OF
GENOTYPE
WEIGHT OF MARKETABLE TUBERS
NON-
Extra-
Large Medium Small Marble
MARKETABLE
large
TUBERS
13.1.1
0.65ab
1.52a
1.22a
0.42
0.35
0.09
96-06
0.65ab
0.84b
1.29a
1.04
0.27
0.12
573275
0.33b
0.59bc
0.29b
0.20
0.07
0.123
5.19.2.2
0.83a
1.05ab
1.39a
0.79
0.4
0.05
676089
0.32b
0.63b
1.27a
0.7
0.1
0.07
GANZA
0.47b
0.69b
0.61ab
0.7
0.16
0.08
GRANOLA
0c
0c
0b
0.04
0.03
0.03
CV (%)
8.93
12.97
16.56
22.17
16.32
4.95
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Total Yield
The mean total yield of the seven genotypes evaluated at La Trinidad,
Benguet under organic production are shown in Table 7, while Plate number 3
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
43
shows tubers harvested from the different genotypes and cultivars. Significant
differences were observed among the genotypes evaluated. Genotype 5.19.2.2
significantly produced the highest total mean yield of 4.57 kg followed by
genotypes 96-06 and 13.1.1 with respective mean total weights of 4.21 and 4.13
kg. The rest of the genotypes produced yield ranging from 0.067 to 2.67 kg.
Results showed low mean yields. This may be attributed to the growth
performance of the genotypes affected by environmental factors. Ivins and
Bremner, (1964) pointed out that to attain high yield in the tropics, a fast
bulking rate and longer bulking period are necessary. Earlier results showed that
the leaf area indices of the genotypes evaluated were lower and higher than the
desired leaf area index of potato, which ranged from 3 to 3.5 at the tuber bulking
stage. According to Kleinkopt, et al (2007) canopies with leaf area indices
greater than 3 to 3.5 are limited by sunlight duration and will not have greater
bulking rates than crops with normal range of leaf area index. Cultivar Granola
was the lowest yielder among the genotypes. This may be attributed to its slow
growth as shown by its low canopy cover, leaf area index, net assimilation rate
and crop growth rate. The same genotype was also attacked with leaf miner and
with late blight as early as 60 DAP which increased rapidly causing early senesce.
This shows that cultivar Granola may not be adapted for organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
44
A
B
C
D
E
F
G
Plate 3. Tubers harvested from the potato genotypes and cultivars.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
45
Computed Marketable Yield
The computed yield in t/ha (Table 7) of the seven genotypes evaluated at
La Trinidad under organic production. Significant variations on the computed
mean yield among the genotypes evaluated were observed.
Genotype 5.19.2.2 significantly had the highest computed marketable
mean yield of 6.33 tons/ha followed by genotypes 13.1.1 and 96-06 with
computed marketable mean yields of 5.72 and 5.46 tons/ha, respectively. The
three genotypes significantly outyielded the check cultivars Ganza and Granola.
The high yielding genotypes were observed to have developed wider canopies as
early as 30 DAP and this continued to increase at 60 DAP but slightly decreased
at 75 DAP. The low yielding genotypes had low canopy covers at 30 DAP which
slowly developed at 75 DAP. Cultivar Granola produced few small leaves and
thin stems, thus, solar radiation was limited resulting to decreased photosynthesis,
thus, lesser assimilates diverted into the tubers. This genotype was also infected
by leaf miner as early as 45 DAP and by late blight at 60 DAP which resulted to
its early senesce. As reported by Dwelle and Love (2006), larger canopy intercept
higher solar radiation, which increased photosynthesis diverting more assimilates
into the tubers during bulking stage resulting to higher yield.
Results showed that genotypes 5.19.2.2, 96-06, and 13.1.1 significantly
produced the highest yield of 6.33, 5.92 and 5.46 tons/ha, respectively. Though
the yield was low, these genotypes were the most adapted under organic
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
46
production at La Trinidad condition. According to Molitas (2005) the usual yield
of potato per hectare in the highlands ranged from 20 - 25 t/ha under conventional
production. The low yield obtained under organic production may be attributed
with the slow growth of the plants as shown by low canopy, leaf area index, net
assimilation rate and crop growth rate. As reported by Burton (1979),
assimilation rates of crops may reach an optimal of 100% if the total soil surface
is covered with green leaves. Likewise, Monteith (1979) stressed that crop
growth rates should be proportional to the rate of photosynthesis, which depends
on the amount of intercepted solar radiation by foliage. The low yield may also
be attributed to the transitional state of the farm used in the study. According to
Anon (2003), the establishment of an organic management system and building of
soil fertility requires an interim period, the conversion period. The same report
put forward that general rule indicates that the first two complete years of
cultivation under control will be considered in transition or in conversion. During
this stage, a decrease in yield is expected.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
47
Table 7. Total yield and computed yield of seven potato genotypes grown at
La Trinidad under organic production.
GENOTYPE TOTAL
YIELD/PLOT
COMPUTED YIELD
(kg)
(tons/ha)
13.1.1
4.13a
5.92a
96-06
4.21a
5.46ab
573275
1.54b
2.72c
5.19.2.2
4.57a
6.33a
676089
2.67b
4.28abc
GANZA
2.47b
3.42bc
GRANOLA
0.067c
0.11d
CV (%)
26.70
29.13
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Dry Matter Contents of Leaves, Stems, Root, stolons and Tubers of the Seven
Potato Genotypes at 45, 60, 75 and 90DAP
Dry matter partitioning in leaves, stems, roots, stolons and tubers of seven
genotypes at 45, DAP is presented in Figure 5.
At 45 DAP, the roots and stolons had the highest dry matter partitioned in
genotypes 5.19.2.2, 13.1.1, 676089 and 96-06 (Figure 5). The tubers partitioned
the second highest dry matter in genotypes 5.19.2.2, 96-06 and 13.1.1. The stems
partitioned had the lowest in genotypes 573275 and 96-06 followed by the dry
matter partitioned into the leaves in genotypes 573275 and 676089.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
48
At 60 DAP, the same trend was exhibited from all the genotypes (Fig. 6).
The dry matter partitioned into the different organs varied among the genotypes.
Dry matter accumulation into the different organs of the potato plants may be
attributed to the genetic characteristics of the genotypes. According to Devlin and
Witham (1983), the leaves nearest the root translocated metabolites primarily to
the roots. Photosynthate moving out of the leaves maybe translocated in the
direction of the roots. This may be one possible reason why dry matter content of
the roots and stolons were high in some genotypes.
30
25
13.1.1
20
96-06
573275
15
5.19.2.2
676089
10
Ganza
Dry matter content
Granola
5
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 5. Dry matter content at 45 DAP of seven potato genotypes grown
at La Trinidad under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
49
30
25
13.1.1
20
96-06
573275
15
5.19.2.2
676089
10
Ganza
Dry matter content
5
Granola
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 6. Dry matter content at 60 DAP of seven potato genotypes grown
at La Trinidad under organic production.
At 75 DAP, the dry matter partitioned into the tubers had increased in all
the genotypes. The dry matter partitioned into the leaves, roots and stolons had
decreased diverting assimilates into the tubers (Figure 7).
The roots and stolons had the highest dry matter partitioned in genotype
5.19.2.2. The highest dry matter partitioned into the tubers was in genotypes
5.19.2.2, 96-06 and 13.1.1. The lowest dry matter was partitioned in the stems in
genotypes 96-06 and 13.1.1 followed by 5.19.2.2, cv. Ganza, 573275 and 676089.
The dry matter partitioned into the roots and stolons in genotypes 13.1.1, 96-06
and 676089 had decreased and the dry matter partitioned into the leaves increased
in genotypes 13.1.1, 96-06 and 5.19.2.2 (Figure 7).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
50
At 90 DAP the dry matter partitioned in the leaves, roots and stolons
increased while dry matter partitioned in the tubers decreased except in genotypes
5.19.2.2 and 96-06. The dry matter partitioned in the stems was lowest in
genotype 573275 followed by 5.19.2.2, 96-06 and cv. Ganza (Figure 7). Results
showed that 5.19.2.2 and 96-06 were of the early maturing genotypes. The stems
were observed to have the lowest dry matter content from 45 to 90 DAP. The
low dry matter in the stem may be due to the fact that the stems are not the storage
organs but merely serve as vehicle for the translocation of assimilates within the
plant.
30
a
a
a
25
a a
a a
13.1.1
ab ab
20
96-06
b
b
a a
a
a
573275
ab ab
a a
a
a
b
15
a
5.19.2.2
a a
676089
10
Ganza
0
Dry matter content
Granola
5
c
b
b
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 7. Dry matter content at 75 DAP of seven potato genotypes grown at La
Trinidad under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
51
40
35
13.1.1
30
96-06
25
573275
20
5.19.2.2
15
676089
Ganza
Dry matter content 10
Granola
5
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 8. Dry matter content at 90 DAP of seven potato genotypes grown
at La Trinidad under organic production.
Dry Matter Accumulation in the Different Plant Organs
Dry matter content of leaves at 45, 60, 75 and 90 DAP is presented in
Figure 9. The dry matter partitioned in the leaves was high at 60 to 75 DAP in
genotype 13.1.1 followed by genotypes 96-06 and 5.19.2.2. Dry matter partitioned
in the leaves at 90 DAP decreased in genotypes 13.1.1 but increased in genotypes
96-06 and 5.19.2.2. Results indicate that most assimilates in the leaves were
translocated to the tubers in genotype 13.1.1 while a three fourth fraction of
assimilates may be translocated to the tubers in genotypes 96-06 and 5.19.2.2.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
52
30
a
a
a
25
a a
13.1.1
ab ab
a
20
a
96-06
abab
573275
15
5.19.2.2
b
676089
10
Ganza
Dry matter content
Granola
5
0
c
b
45
60
75
90
Date after planting
Figure 9. Dry matter content of leaves of seven potato genotypes grown
at La Trinidad under organic production.
The dry matter content of stems among the genotypes evaluated at 45, 60,
75 and 90 DAP is presented in Figure 10. Dry matter partitioned in the stems was
high at 45 DAP in genotypes 96-06 and 13.1.1. Increased dry matter assimilates
in the stem at 60 DAP was shown in cultivar Granola. At 75 DAP genotype
676089 had the highest dry matter assimilates in the stems and continuously
increased at 90 DAP. The dry matter partitioned in the stems of all the genotypes
differed at 45, 60, 75 and 90 DAP. Some genotypes decreased in dry matter
accumulation in the stems at 60 DAP, increased at 75 DAP but decreased at 90
DAP. The fluctuation on dry matter accumulation in the stems may have been
affected by the genetic characteristics of the different genotypes, tested.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
53
35
30
13.1.1
25
96-06
20
573275
a
5.19.2.2
15
a
676089
a
a
Ganza
10
Granola
Dry Matter Content of Stem
5
0
b
45
60
75
90
Days after planting
Figure 10. Dry matter content of stems at 45, 60, 75 and 90 DAP
of seven potato genotypes grown at La Trinidad under organic
production.
Figure 11 shows the dry matter content of roots and stolons at 45, 60, 75
and 90 DAP. The highest dry matter assimilates partitioned in the roots and
stolons were noted at 45 and 75 DAP in genotype 5.19.2.2. . At 90 DAP, dry
matter assimilates partitioned in the roots and stolons increased in most of the
genotypes while this decreased in genotype 5.19.2.2. Results showed that roots
and stolons attained higher dry matter accumulation from 45, 75 and 90 DAP.
According to Devlin and Witham (1983), the leaves nearest the root translocated
metabolites primarily to the roots. Photosynthates moving out of the leaves
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
54
maybe translocated in the direction of the roots. This may be a possible reason
why dry matter content in the roots and stolons were high at 45, 75 and 90 DAP.
40
35
13.1.1
30
a
96-06
25
573275
20
5.19.2.2
a
a
Stolons 15
a
a
676089
Ganza
10
Granola
5
Dry Matter Content of Roots and
0
b
45
60
75
90
Days after planting
Figure 11. Dry matter content of roots and stolons of seven potato genotypes
grown at La Trinidad under organic production.
Dry matter content of tubers at 45, 60, 75 and 90 DAP is presented in
Figure 12. All the genotypes and cultivars tested were observed to have an
increased dry matter content at 60 to 75 DAP. Results showed that dry matter
partitioned into the tubers was high at 45 DAP in genotypes 5.19.2.2 and 13.1.1
while this very low in genotypes 573275 and 676089. Dry matter partitioned in
the tubers increased at 60 to 75 DAP in genotypes 5.19.2.2, 13.1.1 and 96-06.
The high dry matter at 75 DAP indicates early maturity of the genotypes. An
increasing dry matter in genotypes 96-06 and 5.19.2.2 was observed at 90 DAP.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
55
This indicates that maturity in genotypes 96-06 and 5.19.2.2 was at 90 DAP.
Genotype 13.1.1 showed a decrease in dry matter at 75 DAP. The decrease may
indicate maturity of the genotype at 75 DAP.
35
30
13.1.1
a
25
96-06
a
a a
a
20
573275
b
b
5.19.2.2
15
676089
10
Ganza
Granola
5
Dry Matter Content (%) of Tubers
0
45
60
75
90
Days after planting
Figure 12. Dry matter content of tubers of seven potato genotypes grown at La
Trinidad under organic production.
Harvest Index at 45, 60, 75, and 90 DAP
Harvest index of the seven genotypes and cultivars at 45, 60, 75 and 90
DAP is presented in Figure 13. No significant differences among genotypes and
cultivars evaluated were observed at 45 and 60 DAP.
Harvest index differed significantly among the genotypes evaluated at 75
and 90 DAP (Figure 13). At 45 DAP cultivar Granola had the highest harvest
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
56
index followed by cultivar Ganza. The harvest index of cultivar Granola
decreased at 60 DAP while cultivar Ganza had increased harvest index. At 75
DAP genotypes 96-06, 5.19.2.2, cv.Ganza, 676089 and 13.1.1 increased in their
harvest indices. At 90 DAP all the harvest indices of the genotypes and cultivars
decreased except for genotype 96-06 which had an increased harvest index.
Results showed that the harvest indices in most of the genotypes increased which
conforms with the earlier result of an increase in dry matter content in tubers at 75
DAP in all the genotypes. This implies that increase in economic yield may result
on the increase in harvest index. At 90 DAP a decrease in the harvest index was
observed hence dry matter content of tubers at 90 DAP decreased while the dry
matter in the leaves, stolons and tubers increased. Results showed that a decrease
in economic yield would mean low harvest index.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
57
0.6
a
a
0.5
a
13.1.1
a
a a
96-06
0.4
a
573275
b b
0.3
5.19.2.2
bc
bc
676089
0.2
Harvest Index
Ganza
cd
0.1
Granola
0
b
d
45
60
75
90
Days after planting
Figure 13. Harvest index of seven potato genotypes grown at La Trinidad under
organic production.
Leaf Miner Incidence at 45, 60, and 75 DAP
Visual rating for leaf miner incidence was done at the potato vegetative
stage. Observation showed that most of the genotypes were highly resistant at 45
DAP except for cultivar Granola (Figure 14). At 60 DAP most of the genotypes
had intermediate resistant ratings except for genotype 573275 which is highly
resistant. The infestation by leaf miner at 75 DAP slightly increased in genotypes
13.1.1, 96-06, 5.19.2.2, and 676089 while this increased rapidly in cv. Granola.
Based on the results the genotypes evaluated and cultivar Ganza were moderately
resistant to leaf miner while cultivar Granola showed susceptibility to leaf miner
in conformity with the results of Simongo, et al. (2004). The moderate infection
by leaf miner to the genotypes tested showed their resistance to the pest attributed
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
58
to the crop production diversity practiced in the study area and the set-up of
yellow traps.
6
5
13.1.1
4
96-06
573275
3
5.19.2.2
676089
Leaf miner 2
Ganza
Granola
1
0
45
60
75
Days After Planting
Figure 14. Leaf miner ratings of seven potato genotypes grown at La
Trinidad under organic production.
Late Blight Infection at 60 and 75 DAP
Late
blight
infection
at 65 and 75 is presented in Figure 15. Results
showed that the prevailing weather during the evaluation period did not favor the
occurrence of the disease. At 60 to 75 DAP genotypes 5.19.2.2, 573275, 96-06
and 13.1.1 showed zero infections (Figure 15). The genotype 13.1.1 and cultivar
Ganza showed the least infection at 60 and 75 DAP while infection from cultivar
Granola increased at 75 DAP. Results indicate, infection was moderate as
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
59
exhibited by the susceptible cultivar Granola. The low late blight incidence may
be attributed to the low relative humidity that was recorded during the conduct of
the study associated with their genetic characteristics. Horton (1987) reported
that the average relative humidity required for potato production is 86%
confirming that the relative humidity within the evaluation period of the study
did not favor the development of the disease. However, some of the genotypes
tested showed resistance to late blight.
4.5
4
3.5
13.1.1
3
96-06
573275
2.5
5.19.2.2
2
676089
1.5
Ganza
Late Blight Rating
1
Granola
0.5
0
60
75
Days after planting
Figure 15. Late blight rating of seven potato genotypes grown at La Trinidad
under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
60
Correlation Analysis
Correlation Between Meteorological Data and Plant Vigor of the Seven Potato
Genotypes
No significant correlation of plant vigor with minimum temperature,
maximum temperature, relative humidity, rainfall and sunshine duration in all the
genotypes evaluated was noted (Table 8).
In the case of light intensity, significant positive correlation was found on
the plant vigor rating of 96-06, 573275 and cultivar Ganza. This result reveals
that these three genotypes exhibited highly vigorous growth as light intensity
increased. This implies that genotype 96-06, 573275 and cultivar Ganza are
suitable for dry season planting. This finding contradicts the report of Gardner et
al., (1985) that if the light level continues to increase, there is less increase in
carbon exchange rate (CER) for each unit increase in light level until the light
saturation level is reached.
As shown by this results, any increase in light level after this level will not
significantly increase CER; therefore leaves are more efficient at utilizing light
energy at low irradiance levels.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
61
Table 8. Correlation between meteorological data and plant vigor of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza
Granola
Min. Temperature
-
-0.649
-0.649
-
-0.983
-0.649
0.983
Max. Temperature
-
-0.693
-0.693
-
-0.971 -0.6933
0.971
Relative Humidity
-
-0.991
-0.991
-
-0.381
-0.991
0.381
Rainfall
-
0.447
0.470
-
-0.530
0.470
0.530
Sunshine Duration
-
0.872
0.872
-
0.860
0.872
-0.860
Light Intensity
-
0.996*
0.996*
-
0.572
0.996*
0.572
* = significant at 5% level of significance
Correlation Between Meteorological Data and Canopy Cover of the Seven Potato
Genotypes
Canopy cover of the genotypes and cultivars showed no significant
correlation with minimum temperature, RH, rainfall and light intensity.
Maximum temperature had a significant negative correlation (R = -0.949) with
canopy cover while sunshine duration showed a positive significant correlation
(R = 0.983) with canopy cover in genotype 96-06 (Table 9). As results indicate, as
the temperature increases, canopy development decreases confirming the report of
Periera and Shock (2006), that potato is best adapted to cool climates such as
tropical highlands with mean daily temperatures favoring foliar development and
retard in tuberization. Based on the result canopy cover increases as sunshine
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
62
duration increases. This finding corroborates with the report of Anon, (2007)
that long bright days favor photosynthesis and development of top growth. As
this result showed, genotype 96-06 was responsive to increased sunshine duration.
Although correlation was not significant in most of the genotypes,
negative correlation between temperature and canopy was noted. The increase in
temperature may enhance a decrease in canopy cover. Ewing (1981) pointed out
that at high temperature, changes in plant morphology and a significant reduction
in tuber yield. Solar radiation is positively correlated with canopy cover in all the
genotypes tested. The increase in solar radiation may contribute for the
development of greater canopy cover and the long bright days may enhance
development of top growth.
Table 9. Correlation between meteorological data and canopy cover of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275
5.19.2.2
676089
Ganza
Granola
Min. Temperature -0.868 -0.659
-0.970
-0.916
-0.886
-0.960
-0.104
Max. Temperature -0.895 -0.949*
-0.751
-0.910
-0.802
-0.791
-0.764
Relative Humidity -0.221
0.065
-0.450
-0.182
-0.390
-0.400
0.576
Rainfall
0.064
0.264
-0.143
-0.088
0.085
-0.115
0.477
Sunshine Duration 0.874
0.983*
0.677
0.852
0.783
0.724
0.871
Light Intensity
0.294
-0.012
0.534
0.269
0.455
0.483
-0.566
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
63
Correlation Between Meteorological Data and Leaf Area Index of the Seven
Potato Genotypes
Genotype 96-06 (Table 10) showed significant negative correlation
between minimum temperature and leaf area index that as minimum temperature
increases leaf area indices decreased. No significant correlation was shown
among the leaf area indices of the other genotypes with any of the meteorological
data. This implies that the leaf indices of the other genotypes were not affected
by temperature, relative humidity, rainfall, sunshine duration and light intensity.
The result further implies that leaf area index is attributed to the inherent
characteristics of the genotypes.
Table 10. Correlation between meteorological data and leaf area index
of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089
Ganza Granola
Min. Temperature
-0.817 -0.999*
-0.272
-0.631
-0.471
-0.321
-0.280
Max. Temperature -0.983 -0.727
0.496
0.113
0.299
0.451
-0.882
Relative Humidity
0.773
0.302
-0.854
-0.581
-0.725
-0.827
0.792
Rainfall
-0.292
-0.766
-0.805
-0.974
-0.913
-0.835
0.367
Sunshine Duration
0.904
0.526
-0.702
-0.364
-0.534
-0.665
0.973
Light Intensity
-0.615
-0.087
0.748
0.744
0.857
0.930
-0.972
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
64
Correlation Between Meteorological Data and Net Assimilation Rate of the
Seven Potato Genotypes
Except for rainfall with genotype 5.19.2.2, no significant correlation was
shown between meteorological data and net assimilation rate of the genotypes
(Table 11). Rainfall has significant negative correlation with the net assimilation
rate of genotype 5.19.2.2. This indicates that as rainfall increases, the net
assimilation rate of genotype 5.19.2.2 decreases. This implies that 5.19.2.2 is
not suitable for planting during the wet season but rather during the dry season.
During rainy months is genotype produces higher haulm growth with less yield.
Table 11. Correlation between meteorological data and net assimilation rate
of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06 573275
5.19.2.2
676089
Ganza
Granola
Min. Temperature
-0.442 -0.309
-0.280
-0.784
-0.562
-0.789
0.478
Max. Temperature
0.331
0.462
0.489
-0.105
0.196
-0.991
-0.293
Relative Humidity -0.747 -0.834 -0.851
-0.390
-0.647
0.802
0.720
Rainfall
-0.899 -0.828
-0.810
-0.999*
-0.951
-0.247
0.916
Sunshine Duration -0.562 -0.674 -0.697
-0.153
-0.441
0.923
0.529
Light Intensity
0.874
0.735
0.745
0.581
0.798
-0.551
0.854
** = Highly significant at 1% level of significance
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
65
Correlation Between Meteorological Data and Crop Growth Rate of the Seven
Potato Genotypes
Correlation between meteorological data and crop growth rate is presented
in Table 12. Significant negative correlation between rainfall and crop growth
rate was noted in genotypes 13.1.1 and 5.19.2.2. It was observed that, as rainfall
increase the crop growth rates of genotypes 13.1.1 and 5.19.2.2 decreases. This
implies that genotypes 13.1.1 and 5.19.2.2 are best adapted under dry season
cropping. The crop growth rates of the other genotypes and cultivars were not
affected by any of the meteorological data.
Table 12. Correlation between meteorological data and crop growth rate of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICENT
DATA
13.1.1
96-06 573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.799
-0.895
-0.031
-0.831
-0.049
-0.550
0.693
Max. Temperature
-0.130
-0.307
0.692
-0.183
0.679
0.212
-0.029
Relative Humidity
-0.367
-0.193
-0.955
-0.316
-0.949
-0.659
0.510
Rainfall
-0.999**
-0.981
-0.638
-0.998*
-0.651
-0.946
0.790
Sunshine Duration
-0.128
0.052
-0.854
-0.075
-0.845
-0.455
0.284
Light Intensity
0.561
0.403
0.797
0.516
0.795
0.807
-0.686
* = Significant at 5% level of significance
** = Highly significant at 1% level of significance
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
66
Correlation Between Meteorological Data and Dry Matter Content of Leaves of
the Seven Potato Genotypes
There is significant effect of the environmental factors on dry matter
contents of the leaves of genotypes 13.1.1, 573275 and cultivar Granola (Table
13). Significant positive correlation was exhibited between 13.1.1 and rainfall.
Significant negative correlation (R = 0.979) between dry matter content of leaves
and minimum temperature was shown in genotype 573275. This indicates that dry
matter content of the leaves decreases as temperature increases. Significant
positive correlation was also observed between sunshine duration and dry matter
content of the leaves of cultivar Granola. Hence, as sunshine duration increases
dry matter content of the leaves increases. This implies that cultivar Granola is
best grown under long bright days.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
67
Table 13. Correlation between meteorological data and dry matter content of
leaves of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.436
-0.754 -0.979*
-0.669
-0.922
-0.777
-0.314
Max. Temperature -0.009
0.051
0.098
-0.087
-0.150
-0.429
-0.768
Relative Humidity -0.425 -0.366
-0.023
-0.270
0.040
0.283
0.864
Rainfall
-0.947*
-0.824
-0.171
-0.899
-0.537
-0.602
-0.059
Sunshine Duration -0.259 -0.135
0.217
-0.050
0.297
0.518
0.962*
Light Intensity
0.700
0.432
-0.334
0.443
-0.133
-0.213
-0.773
* = Significant at 5% level of significance
Correlation Between Meteorological Data and Dry Matter Content of Stems of the
Seven Potato Genotypes
Correlation between meteorological data and dry matter content of stems
is presented in Table 14. Significant positive correlation between rainfall and dry
matter content of the stems was exhibited by genotype 96-06. This indicates that
the dry matter content of the stems in genotype 96-06 increases as rainfall
increases. Thus, this implies that genotype 96-06 is best adapted under wet season
cropping..
Genotype 573275 showed significant positive correlations between
maximum temperature and dry matter content of the stems. As results show dry
matter content of the stems of genotype 573275 increased as temperature
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
68
increased. Negative significant correlation (R = -0.976) between sunshine
duration and dry matter content in the stems was also shown by genotype 573275.
Correlation between dry matter content of stems and sunshine duration showed
that dry matter content of stems increases as sunshine duration decreases. This
implies that genotype 573275 is best adapted under short bright days.
Table 14. Correlation between meteorological data and dry matter content of
stems of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICEINT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.200
0.797
0.728
0.221
-0.435
-0.400
-0.599
Max. Temperature -0.487
0.318
0.984*
0.125
-0.282
0.135
-0.716
Relative Humidity
0.563
0.125
0.912
-0.020
0.092
-0.497
0.612
Rainfall
0.142
0.943*
0.191
0.225
-0.409
-0.757
-0.247
Sunshine Duration
0.539
-0.104
-0.976*
-0.076
0.194
-0.321
0.684
Light Intensity
-0.554
-0.342
0.796
-0.035
0.013
0.642
-0.506
* = Significant at 5% level of significance
Correlation Between Meteorological Data and Dry Matter Content of Roots and
Stolons of the Seven Potato Genotypes.
The correlations between metrological data and dry matter content of roots
and stolons are presented in Table 15. No significant correlation was shown
among meteorological data and dry matter content of roots and stolons in all the
genotypes and cultivars evaluated. This may imply that dry matter content of the
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
69
roots and stolons was not much affected by the temperature, relative humidity,
rainfall, sunshine duration and light intensity. As the result implies dry matter
contents of roots and stolons may be affected by the inherent characteristics of
the genotypes.
Table 15. Correlation among meteorological data and dry matter content of roots
and stolons of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
0.195
0.331
0.105
0.858
0.113
-0.360
-0.531
Max. Temperature -0.444 -0.299
-0.106
0.708
-0.518
-0.341
-0.702
Relative Humidity
0.802
0.689
0.235
-0.407
0.850
0.236
0.641
Rainfall
0.735
0.808
0.267
0.661
0.677
-0.234
-0.155
Sunshine Duration
0.637
0.504
0.174
-0.577
0.700
0.298
0.692
Light Intensity
-0.917
-0.830
-0.281
0.217
-0.948
-0.162
-0.555
Correlation Between Meteorological Data and Dry Matter Content of Tubers of
the Seven Potato Genotypes.
Table 16 shows the correlation between meteorological data and dry
matter content of tubers. No significant correlation was observed between the
meteorological data and dry matter content of tubers in all the genotypes and
cultivars evaluated. Tuber dry matter content of all the genotypes, as the results
show was not affected by temperature, relative humidity, rainfall, sunshine
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
70
duration and light intensity. This indicates that dry matter content of tubers is
attributed to their genetic characteristics and not affected by environmental
factors. As Peet (2006) reported, dry matter content varies between varieties and
is a strongly inherited characteristic.
Table 16. Correlation between meteorological data and dry matter content of
tubers of seven genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.223
-0.677
-0.767
0.105
-0.351
-0.566
-0.513
Max. Temperature
0.391
-0.292
-0.308
0.562
0.257
0.034
0.045
Relative Humidity -0.743 -0.073
-0.117
-0.752
-0.641
-0.472
-0.449
Rainfall
-0.726
-0.779
-0.906
-0.377
-0.798
-0.919
-0.849
Sunshine Duration -0.580
0.117
0.103
-0.674
-0.458
-0.256
-0.250
Light Intensity
0.862
0.255
0.326
0.785
0.784
0.658
0.619
Correlation Between Meteorological Data and Harvest Index of the Seven Potato
Genotypes
The correlation between meteorological data and harvest index of all the
genotypes and cultivars evaluated shown in Table 17. No significant correlation
between meteorological data and harvest index was noted. As the result implies,
the harvest indices of all the genotypes and cultivars evaluated were not affected
by the temperature, rainfall, relative humidity, sunshine duration and light
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
71
intensity. This therefore implies that harvest index was solely attributed to the
genetic characteristics of the genotypes and cultivars studied.
Table 17. Correlation between meteorological data and harvest index of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
0.212
-0.729
-0.737
0.058
0.035
0.276
0.078
Max. Temperature
0.597
-0.228
-0.249
0.615
0.375
0.546
-0.413
Relative Humidity -0.724 -0.207
-0.181
-0.866
-0.527
-0.600
0.669
Rainfall
-0.244
-0.923
-0.915
-0.503
-0.306
-0.093
0.521
Sunshine Duration -0.678
0.015
0.040
-0.759
-0.462
-0.589
0.554
Light Intensity
0.728
0.412
0.389
0.821
0.561
0.577
-0.743
Correlation Among Characters
Meyer and Anderson (1952) reported that the development of every organ
in growing plant is attributed to some degree by physiological processes of
physico- chemical conditions prevailing in some other organ or organs. Such
relationship existing among the organs of a plant are termed growth correlations
or simply correlations. Growth correlations are not only exerted by one organ on
another but also occur among tissues and even among cells.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
72
Table 18 shows the summary of the correlation coefficient of seven potato
genotypes characters studied. Canopy cover showed no significant correlation
with the other plant characters except on the harvest index.
Canopy cover showed significant positive correlation (R = 0.665) with
harvest index. Thus, as canopy cover increases harvest index increases which
contradicts the statement of Belanger, et al., ( 2000), that any factor resulting in a
decrease in total biomass will indirectly decrease the harvest index . No
significant correlation was observed in leaf area index with other plant characters.
This result indicates that leaf area index was not affected by plant character.
Significant positive correlation between net assimilation rate and crop
growth rate was noted. It was noted that net assimilation rate increased as the
crop growth rate increased which is conclusive since crop growth rate is the
product of net assimilation rate when multiplied with leaf area index as cited by
Gardner et al. (1985).
Significant positive correlation (R = 0.652) between net assimilation rate
and extra large tuber weight was observed. This indicates that extra large tuber
weight increase as net assimilation rate increases.
Correlation in crop growth rate with other characters was not significant.
This implies that crop growth rate was not affected by other plant characters.
For the yield components, no significant correlations were noted, thus,
none of the plant characters studied affected the yield.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
73
Dry matter content of leaves, stems, roots and stolons and tubers showed
no significant correlation among all the characters studied.
No significant correlation between harvest index and among other plant
characters, which implies that harvest index, was not affected by any of the
characters. As results showed, dry matter content of leaves, stems, roots, stolons
and tubers were not affected by any other plant character.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
74
Table 18. Correlation among growth and yield parameters of the seven genotypes evaluated
CC
LAI
NAR
CGR
XLWT.
LWT.
MWT.
SWT.
MAR WT.
NMWT
TOT.YLD.
LDMC
SDMC
RSDMC
TDMC
HI
CC
1.000
-0.379
-0.126
-0.279
0.127
-0.191
0.055
0.189
0.261
0.121
0.314
0.030
-0.186
-0.246
0.407
0.665*
LAI
1.000
0.323
0.548
0.201
-0.463
-0.283
-0.291
0.040
-0.419
-0.286
0.085
-0.371
-0.092
-0.064
0.197
NAR
1.000
0.840**
0.652*
0.033
-0.155
-0.159
-0.079
-0.525
0.062
0.061
-0.087
0.535
-0.076
-0.508
CGR
1.000
0.322
0.696*
0.418
-0.224
-0.099
-0.529
-0.050
0.080
-0.240
0.463
-0.008
-0.367
XLWT
1.000
-0.445
0.226
0.106
0.414
-0.017
0.390
0.056
0.285
0.224
-0.361
-0.019
LWT.
1.000
-0.061
-0.119
-0.742
-0.293
-0.147
-0.283
0.108
0.193
0.253
-0.259
MWT.
1.000
0.007
0.194
0.476
0.714
-0.282
0.072
-0.236
-0.011
-0.098
SWT.
1.000
0.038
0.169
0.578
-0.072
-0.180
-0.411
-0.260
0.039
MRWT.
1.000
0.279
0.408
0.117
0.047
-0.199
-0.144
0.083
NMWT.
1.000
0.234
0.098
0.198
-0.121
-0.162
-0.095
Tot. yld.
1.000
-0.255
-0.183
-0.330
-0.101
-0.097
LDMC
1.000
0.329
0.405
-0.080
-0.148
SDMC
1.000
0.542
-0.271
-0.257
RSDMC
1.000
0.217
-0.379
TDMC
1.000
0.433
HI
1.000
** = Highly significant at 5% level of significance
XLWT = extra large tuber weight
TOT YLD = total yield
* = Significant at 5% level of significance LWT = large tuber weight LDMC = leaves dry matter content
CC = canopy cover
MWT = medium tuber weight
SDMC = stem dry matter content
LAI = leaf area index
SWT -= small tuber weight
RSDMC = root & stolons dry matter content
NAR = net assimilation rate
MRWT = marble tuber we
TDMC = tuber dry matter content
CGR = crop growth rate
NMWT = non-marketable tuber weight
HI = harvest index
Growth, yield and dry matter partitioning of potato genotypes under organic production at La Trinidad, Benguet / Donita K. Simongo. 2007
75
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted to determine assimilates partitioning in the
leaves, stems, roots, stolons and tubers during the different stages of the potato
plant development; compare the efficiency of potato genotypes in terms of dry
matter partitioning under organic production, and determine the best time of
harvesting for optimum dry matter accumulation.
Seven potato genotypes and cultivars grown and selected from previous
studies under organic production were evaluated from November 2006 to
February 2007 at La Trinidad, Benguet under organic production. Treatments
were laid out following the Randomized Complete Block Design with 40 tubers
per replication. Destructive sampling was done at 45 DAP and every 15 days
thereafter until harvest. The data gathered were: meteorological data, soil
analysis, growth parameters, yield components, dry matter parameters and other
data. The data was analyzed through ANOVA using the single factorial in RCBD
except for leaf miner and late blight ratings. Correlation between meteorological
data and growth characters and in among plant characters were analyzed using
Pearson correlation movement correlation coefficient (R), which characterizes the
independence of X and Y.
The minimum and maximum air temperature during the study period
ranged from 12.6 to 15.6 oC and 23.5 to 24.2 oC, respectively while relative
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
76
humidity ranged from 77 to 80 %. A very low rainfall about 2.5, 2.4 and 0.05 mm
was noted in November, December and January. Sunshine duration ranged from
381.4 to 521.6 mm. Light intensity ranged from 45.1 to 76.4 Klux. Soil pH is
6.72 before and 6.31 after harvest. Organic matter, phosphorus, potassium and
nitrogen in the soil increased.
Genotype 13.1.1 significantly had high plant survival of 98 % followed by
genotypes 5.19.2.2 and 13.1.1 with plant survival of 97 and 85%, respectively.
Genotypes 13.1.1 and 5.19.2.2 significantly had highly vigorous growth at 30, 45
and 60 DAP. Cultivar Granola had moderate vigor at 30 and 45 DAP and less
vigor at 60 DAP.
Canopy cover was significantly high in genotype 96-06 followed by
5.19.2.2 and 13.1.1. On leaf area index genotype 5.19.2.2 had the highest leaf
area index at 45 DAP followed by genotypes 96-06 and 13.1.1. Genotype
5.19.2.2 had the highest leaf area index at 45 DAP followed by genotypes 96-06
and 13.1.1 while 573275 and cultivar Granola had the lowest leaf area index. At
60 DAP, all the genotypes increased in their leaf area indices with genotype
5.19.2.2 having the highest followed by 96-06 and 676089. Genotypes 5.19.2.2,
96-06, 13.1.1 and cultivar Ganza showed an increasing leaf area indices at 75
DAP while genotypes 676089, 573275 and cultivar Granola decreased.
No significant differences were observed among genotypes on their net
assimilation rates at 45 and 75 DAP. At 60 DAP genotype 5.19.2.2 significantly
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
77
had the highest net assimilation rate. On the crop growth rate, genotype 5.19.2.2
had the highest at 45 to 65 DAP followed by 676089 at 45 DAP and 96-06 at 60
DAP followed by 676089. Genotype 676089 increased in crop growth rate
attaining the highest among the genotypes at 75 DAP. Genotype 573275 and
cultivar Ganza increased at 75 DAP but not significantly comparable with
676089.
Genotypes 5.19.2.2, 13.1.1 and 96-06 had the highest total yield of 4.57,
4.21 and 4.13 kg, respectively and computed marketable yields with respective
means of 6.33, 5.46 and 5.92 tons/ha. Genotype 13.1.1 had produced the most
marketable tubers and the highest weight of tubers. Genotype 5.19.2.2 produced
the heaviest weights of large, medium, small and marble tubers.
On the partitioning of assimilates in different plant organs of the seven
potato genotypes and cultivars, the highest assimilate was partitioned into the
roots and stolons of genotype 5.19.2.2 at 45, 60 and 75DAP and in cultivar Ganza
at 90 DAP. The least assimilate was partitioned into the stems in genotypes
573275, 676089 and 96-06 at 45 to 60 DAP; in genotypes 13.1.1 and 96-06 at
75DAP and in genotype 573275 at 90 DAP.
As to assimilate partitioning in the leaves, highest dry matter content in
the leaves in genotype 13.1.1 was noted at 75 DAP. The dry matter content in the
stems was high at 90 DAP in genotype 676089. In the roots and stolons, the
highest assimilates was partitioned at 90 DAP in cultivar Ganza. The highest
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
78
assimilates partitioned in tubers was noted at 90 DAP in genotypes 96-06 and
5.19.2.2 but at 75 DAP high assimilate was partitioned in all the genotypes.
Harvest index differed significantly among the genotypes evaluated at 75
and 90 DAP but did not differ at 45 and 60 DAP. Cultivar Granola had the
highest harvest index at 45 DAP but decreased at 60 DAP with cultivar Ganza
having the highest harvest index followed by genotypes 96-06 and 573275. At 75
DAP, genotypes 96-06, 5.19.2.2, cultivar Ganza, 676089 and 13.1.1 increased in
their harvest indices while 573275 decreased. At 90 DAP, all the harvest indices
of the genotypes decreased except for genotype 96-06 which had an increased in
harvest index.
Data on leaf miner and late blight incidence was recorded during the
conduct of the study. Genotypes 5.19.2.2, 573275, 96-06 and 13.1.1 had zero late
blight infection at 60 to 75 DAP. The genotype 13.1.1 and cultivar Ganza showed
the least infection but was moderately infected at 75 DAP. At 60 DAP most of
the genotypes were of intermediate resistance except for genotype 573275 which
is highly resistant. The infestation of leaf miner at 75 DAP slightly increased from
genotypes 13.1.1, 96-06, 5.19.2.2, and 676089 while this increased rapidly with
cultivar Granola. Infection of late blight was moderate as showed by the
susceptible check cultivar Granola with late blight rating of 4 with only 25%
infection at 75 DAP while the rest showed minimal infection with ratings of 2
(2.5%) to zero infection at 75 DAP.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
79
Correlation analysis revealed significant positive correlations in: plant
vigor with light intensity in genotypes 96-06, 573275, and cultivar Ganza; dry
matter content of leaves with sunshine duration in cultivar Granola; dry matter
content of stems with rainfall in genotype 96-06 and with maximum temperature
in genotype 573275. Significant negative correlations was observed in: canopy
cover with maximum temperature in genotype 96-06; crop growth rate with
rainfall in genotypes 13.1.1 and 5.19.2.2; leaf area index with minimum
temperature. No significant correlation was observed in temperature, relative
humidity, rainfall, sunshine duration and light intensity with dry matter content of
roots, stolons, tubers and harvest indices in all the genotypes and cultivars tested.
On the correlation among plant characters, canopy cover is positively
correlated significantly with harvest index, net assimilation rate and extra large
tubers and between net assimilation rate and crop growth rate.
Conclusions
Based on the results of the study the following conclusions are drawn:
1) Among the genotypes and cultivars evaluated 96-06, 13.1.1 and 5.19.2.2 were
best performers based on survival, vigor, canopy cover, leaf area index, net
assimilation rate and crop growth rate.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
80
2) Genotypes 5.19.2.2, 96-06 and 13.1.1 had the highest total yield per plot and
computed marketable yield indicating that these genotypes may be the most
adapted under organic production at La Trinidad.
3) On the dry matter partitioning of assimilates, the roots and stolons had the
highest assimilates partitioned in genotype 5.19.2.2 at 45, 60 and 75 DAP.
4) Assimilates were partitioned in the tubers at 75 DAP in most of the
genotypes except for 96-06 and 5.19.2.2 which had partitioned assimilates in
the tubers at 90 DAP.
5) Dry matter content of roots, stolons, tubers and harvest index were not
affected by temperature, rainfall, sunshine duration and light intensity in any
of the genotypes. This shows that dry matter content is attributed to the
inherent characteristics of the genotypes, tested.
6) The significant positive correlation of dry matter content of some organs
with sunshine duration indicates the importance of longer expressure of the
genotypes to bright sunshine.
7) The negative correlation of crop growth rate with rainfall in 13.1.1 and
5.19.2.2 shows the suitability of these genotypes to dry season planting.
8) Among the genotypes evaluated 573275 was highly resistant to leaf miner,
cultivar Ganza was intermediate and 13.1.1, 5.19.2.2, 676089 and 96-06
were moderately resistant. Genotypes 5.19.2.2, 573275, 96-06 and 13.1.1
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
81
were resistant to late blight. The resistance of these genotypes to leaf miner
and late blight indicates their adaptability to organic production.
Recommendations
Based on the results of the study, the following are recommended:
1. Genotypes 96-06, 13.1.1 and 5.19.2.2 may be planted for organic production
at La Trinidad, Benguet.
2. Genotypes 13.1.1, 573275, 676089, cultivars Ganza and Granola may be
harvested as early as 75 DAP. Genotypes 96-06 and 5.19.2.2 could be
harvested at 90 DAP.
3. Since sunshine duration significantly affects dry matter content of leaves
cultural management practices that encourage maximum sunlight interception
should be practiced. These practices may include proper spacing and
cropping scheme.
4. Genotypes 13.1.1 and 5.19.2.2 are best planted during the dry season.
5. Since dry matter content of the tubers was not affected by any of the
environmental factors in the study, verification should be done in other
locations and seasons.
6. The strong indication that dry matter allocation in the tubers is largely genetic
encourages researchers to continuously search for genotypes with efficient dry
matter partitioning, high yield and harvest index under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
82
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ANON, 2005. Organic Production and Sustainable Agriculture. Marin Organic P.
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irrigation. American Journal of Potato Researches (2001) 78:109-107.
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BEUKEMA, H. P. and D. E. VAN DER ZAAG. 1979. Potato inprovement:
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Growth, yield and dry matter partitioning of potato genotypes under organic
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88
APPENDICES
APPENDIX TABLE 1. Analysis of variance for plant survival
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUT
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
ED F
.05 .01
Replication 2 392.667
196.333
Treatment 6
11110.286 1851.714
11.17**
3.00 4.82
Error 12
1990.000
165.833
Total 20
13492.952
** Highly significant CV% = 17.73
SX = 7.43
APPENDIX TABLE 2. Analysis of variance for plant vigor at 30 dap
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.667
8.333
Treatment 6 14.476
2.413
6.20** 3.00
4.82
Error 12
4.667
0.389
Total 20
19.810
** Highly significant CV% = 16.58
SX = 0.36
APPENDIX TABLE 3. Analysis of variance for plant vigor at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.286
0.143
Treatment 6
10.286
1.714
12.0** 3.0
4.82
Error 12
1.714
0.143
Total 20
** Highly significant CV% = 8.82
SX = 0.22
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
89
APPENDIX TABLE 4. Analysis of variance for plant vigor at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.381
0.190
Treatment 6
21.333
3.556
44.8**
3.0 4.82
Error 12
0.952
0.079
Total 20
22.667
** Highly significant CV% = 6.50
SX = 0.16
APPENDIX TABLE 5. Canopy cover at 30 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2
299.810
149.905
Treatment 6
2078.000
346.333
8.01**
3.0 4.82
Error 12
518.857
43.238
Total 20
2896.667
** Highly significant CV% = 18.76
SX = 3.80
APPENDIX TABLE 6. Analysis of variance for canopy cover at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 590.095
295.048
Treatment 6
3190.286
531.714
10.92**
3.0 4.82
Error 12
584.572
48.714
Total 20
4364.952
** Highly significant CV% = 22.48
SX = 4.03
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
90
APPENDIX TABLE 7. Analysis of variance for canopy cover at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 586.952
293.476
Treatment 6
5134.476
855.746
29.48**
3.0 4.82
Error 12
348.381
29.032
Total
20
6089.810
** Highly significant CV% = 12.76
SX = 3.11
APPENDIX TABLE 8. Analysis of variance for canopy cover at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 60.667
30.333
Treatment 6
3009.619
501.603
24.01** 3.0
4.82
Error 12
250.667
20.889
Total 20
3320.952
** Highly significant CV% = 17.32
SX = 2.64
APPENDIX TABLE 9. Analysis of variance for leaf area index at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.004
0.002
Treatment 6 0.050
0.008
7.06**
3.0 4.82
Error 12
0.014
0.001
Total 20
0.069
** Highly significant CV% = 4.30
SX = 0.02
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
91
APPENDIX TABLE 10. Leaf area index at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 111.870
55.935
Treatment 6
40293.104 6715.517
21.96**
3.0 4.82
Error 12
3669.256
305.771
Total 20
44074.230
** Highly significant CV% = 16.43
SX = 10.10
APPENDIX TABLE 11. Analysis of variance for leaf area index at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 190.062
95.031
Treatment 6
49807.532 8301.255
12.31** 3.0
4.82
Error 12
8091.235
674.270
Total
20
58088.829
** Highly significant CV% = 25.94
SX = 14.99
APPENDIX TABLE 12. Net assimilation rate at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 16.835
8.417
Treatment 6
151.713
25.285
1.67ns
3.0 4.82
Error 12
182.234
15.186
Total 20
350.782
nsnot significant CV% = 20.63
SX = 2.25
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
92
APPENDIX TABLE 13. Analysis of variance for net assimilation rate at 60
DAP (g/cm2/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 8.081
4.041
Treatment 6 0.547
8.425
1.57ns
3.0 4.82
Error 12
64.367
5.364
Total 20
72.995
nsnot significant CV% = 13.23
SX = 1.34
APPENDIX TABLE 14. Analysis of variance for net assimilation rate at
75 DAP (g/cm2/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 1.738
0.869
Treatment 6
84.838
14.140
3.63*
3.0 4.82
Error 12
46.736
3.895
Total 20
133.312
*Significant CV% = 21.95
SX = 1.14
APPENDIX TABLE 15. Analysis of variance for crop growth rate at 45 DAP
(g/cm2soil/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.244
0.122
Treatment 6
4.691
0.782
2.20ns
3.0 4.82
Error 12
4.268
0.356
Total 20
4.268
nsnot significant CV% = 19.63
SX = 0.34
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
93
APPENDIX TABLE 16. Analysis of variance for crop growth rate at 60 DAP
(g/cm2soil/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.079
0.039
Treatment 6
1.734
0.287
1.44ns
3.0 4.82
Error
12 2.387
0.199
Total 20
4.189
nsnot significant CV% = 17.77
SX = 0.26
APPENDIX TABLE 17. Analysis of variance for crop growth rate at 75 DAP
(g/cm2soil/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.066
0.033
Treatment 6 3.191
0.532
3.72*
3.0
4.82
Error 12
1.922
0.160
Total 20
5.179
*Significant CV% = 26.86
SX = 0.23
APPENDIX TABLE 18 Analysis of variance for number of marketable extra
large tubers per plot.
SOURCE OF DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 69.714
34.857
Treatment 6
182.476
30.413
3.41*
3.0
4.82
Error 12
106.952
8.913
Total 20
359.952
*Significant CV% = 26.32
SX = 1.72
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
94
APPENDIX TABLE 19. Analysis of variance for number of marketable large
tubers per plot
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 249.810
124.905
Treatment 6
1641.905
273.651
5.95**
3.0 4.82
Error 12
551.524
45.960
Total 20
2443.238
** Highly significant CV% = 20.95
SX = 3.91
APPENDIX TABLE 20 Analysis of variance for number of marketable medium
tubers per plot.
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 382.952
191.476
Treatment 6
3032.667
505.444
268ns
3.0 4.82
Error 12
2265.048
188.754
Total 20
5680.667
nsnot significant CV% = 27.28
SX = 7.93
APPENDIX TABLE 21. Analysis of variance for number of marketable small
tubers per plot
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 50.667
25.333
Treatment 6
1334.952
222.492
5.33** 3.0
4.82
Error 12
501.333
41.778
Total 20
1886.952
** Highly significant CV% = 17.07
SX = 3.73
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
95
APPENDIX TABLE 22. Analysis of variance for number of marketable marble
tubers per plot.
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 514.667
257.333
Treatment 6
1162.952
193.825
1.02ns
3.0 4.82
Error 12
2279.333
189.944
Total 20
1906.952
nsnot significant CV% = 25.66
SX = 7.96
APPENDIX TABLE 23. Analysis of variance for number of non-marketable
tubers per plot
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 256.095
128.048
Treatment 6
1761.619
293.603
1.48ns
3.0 4.82
Error 12
2379.238
198.270
Total 20
43.396.952
nsnot significant CV% = 28..45
SX = 8.13
APPENDIX TABLE 24. Analysis of variance for weight of marketable extra
large tubers per plot (kg)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.106
0.053
Treatment 6 1.361
0.227
6.96**
3.0 4.82
Error 12
0.391
0.033
Total 20
1.858
** Highly significant CV% = 8.93
SX = 0.10
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
96
APPENDIX TABLE 25. Analysis of variance for weight of marketable large
tubers per plot (kg)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 1.026
0.513
Treatment 6 3.871
0.645
5.20** 3.0
4.82
Error 12
1.487
0.124
Total 20
6.384
** Highly significant CV% = 12.97
SX = 0.20
APPENDIX TABLE 26. Analysis of variance for weight of marketable
medium tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 1.427
0.713
Treatment 6 5.123
0.854
4.11*
3.0 4.82
Error 12
2.495
0.208
Total 20
9.045
* Significant CV% = 16.56
SX = 0.26
APPENDIX TABLE 27. Analysis of variance for weight of marketable small
tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.830
0.415
Treatment 6 2.211
0.369
2.09ns
3.0 4.82
Error 12
2.117
0.176
Total 20
5.158
nsnot significant CV% = 22.17
SX = 0.24
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
97
APPENDIX TABLE 28. Analysis of variance for weight of marketable marble
tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.176
0.088
Treatment 6 0.333
0.055
0.88ns
3.0 4.82
Error 12
0.753
0.063
Total 20
1.262
nsnot significant CV% = 16.32
SX = 0.14
APPENDIX TABLE 29. Analysis of variance for weight of non-marketable
tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.008
0.004
Treatment 6 0.022
0.004
1.02ns
3.0 4.82
Error 12
0.042
0.004
Total 20
0.072
nsnot significant CV% = 4.95
SX = 0.03
APPENDIX TABLE 30. Analysis of variance for total yield per plot (kg)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 2.092
1.046
Treatment 6
48.632
8.105
14.19** 3.0
4.82
Error 12
6.854
0.571
Total 20
57.578
** Highly significant CV% = 26.70
SX = 0.44
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
98
APPENDIX TABLE 31. Analysis of variance for yield tons/ha
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 21.542
10.771
Treatment 6
135.754
22.626
7.31** 3.0
4.82
Error 12
37.117
3.093
Total 20
194.413
** Highly significant CV% = 29.74
SX = 1.01
APPENDIX TABLE 32. Analysis of variance for dry matter content of leaves
at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 82.608
41.304
Treatment 6
74.864.
12.477
2.33ns 3.0
4.82
Error 12
64.284
5.357
Total 20
221.756
nsnot significant CV% = 17.16
SX = 1.34
APPENDIX TABLE 33. Analysis of variance for dry matter content of leaves
at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 266.661
133.330
Treatment 6
236.292
39.382
1.91ns
3.0 4.82
Error 12
246.938
20.578
Total 20
749.891
nsnot significant CV% = 27.09
SX = 2.62
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
99
APPENDIX TABLE 34. Analysis of variance for dry matter content of leaves
at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication
2
96.538
48.269
Treatment 6
1119.201
186.534
6.09**
3.0 4.82
Error
12
367.475 30.623
Total 20
1583.214
** Highly significant CV% = 18.89
SX = 3.19
APPENDIX TABLE 35. Analysis of variance for dry matter content of leaves
at 90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 170.217
85.108
Treatment 6
1422.506
237.084
10.57**
3.0 4.82
Error 12
269.221
22.435
Total 20
1861.221
**Highly significant CV% = 24.94
SX = 10.60
APPENDIX TABLE 36. Analysis of variance for dry matter content of stems at
45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 340.382
170.191
Treatment 6
112.389
18.731
0.48ns 3.0
4.82
Error 12
472.442
39.370
Total 20
925.213
nsnot significant CV% = 22.83
SX = 3.62
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
100
APPENDIX TABLE 37. Analysis of variance for dry matter content of stems at
60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 65.084
32.542
Treatment 6
91.710
15.285
1.08ns 3.0
4.82
Error 12
169.768
14.147
Total 20
326.562
nsnot significant CV% = 15.43
SX = 2.17
APPENDIX TABLE 38. Analysis of variance for dry matter content of stems at
75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 77.493
38.747
Treatment 6
1734.945
289.157
2.68ns 3.0
4.82
Error 12
1294.393
107.866
Total 20
3106.831
nsnot significant CV% = 16.11
SX = 2.20
APPENDIX TABLE 39. Analysis of variance for dry matter content of stems at
90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 77.493
38.747
Treatment 6
1734.945
289.157
2.68ns
3.0 4.82
Error 12
1294.393
107.866
Total 20
3106.831
ns not significant CV% = 24.44
SX = 5.99
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
101
APPENDIX TABLE 40. Analysis of variance for dry matter content of roots
and stolons at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 72.317
36.159
Treatment 6
361.091
60.182
2.14ns
3.0 4.82
Error 12
336.808
28.067
Total 20
770.216
nsnot significant CV% = 23.06
SX = 3.06
APPENDIX TABLE 41. Analysis of variance for dry matter content of roots
and stolons at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 116.721
58.361
Treatment 6
372.525
62.087
0.68ns 3.0
4.82
Error 12
1093.900
91.158
Total 20
1583.146
nsnot significant CV% = 5.94
SX = 5.51
APPENDIX TABLE 42. Analysis of variance for dry matter content of roots
and stolons at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 932.340
466.170
Treatment 6
1148.414
191.402
3.56* 3.0
4.82
Error 2
646.001
53.833
Total 20
2726.755
*Significant CV% = 22.40
SX = 4.24
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
102
APPENDIX TABLE 43. Analysis of variance for dry matter content of roots
and stolons at 90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 150.321
75.161
Treatment 6
1970.644
378.444
2.01* 3.0
4.82
Error 12
1955.978
162.998
Total 20
4076.963
ns not significant CV% = 11.70
SX = 7.37
APPENDIX TABLE 44. Analysis of variance for dry matter content of tubers
at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 139.803
69.902
Treatment 6
286.771
47.795
1.14ns
3.0 4.82
Error 12
503.002
41.917
Total 20
929.576
nsnot significant CV% = 23.39
SX = 3.74
APPENDIX TABLE 45. Analysis of variance for dry matter content of tubers
at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 6.963
3.481
Treatment 6
74.500
12.417
1.77ns 3.0
4.82
Error 12
84.226
7.019
Total 20
165.689
nsnot significant CV% = 13.52
SX = 1.53
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
103
APPENDIX TABLE 46. Analysis of variance for dry matter content of tubers at
75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.800
0.400
Treatment 6
104.373
17.395
6.26**
3.0 4.82
Error 12
33.354
2.779
Total 20
138.527
nsnot significant CV% = 7.61
SX = 0.96
APPENDIX TABLE 47. Analysis of variance for dry matter content of tubers at
90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 20.425
10.212
Treatment 6
339.351
56.558
2.89ns 3.0
4.82
Error 12
234.458
19.538
Total 20
594.234
nsnot significant CV% = 21.79
SX = 2.55
APPENDIX TABLE 48. Analysis of variance for harvest index at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.010
0.005
Treatment 6 0.150
0.025
1.12ns
3.0 4.82
Error 12
0.267
0.022
Total 20
0.427
nsnot significant CV% = 9.53
SX = 0.09
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
104
APPENDIX TABLE 49. Analysis of variance for harvest index at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.004
0.002
Treatment 6 0.022
0.004
0.27ns 3.0
4.82
Error 12
0.166
0.014
Total 20
0.193
nsnot significant CV% = 26.73
SX = 0.07
APPENDIX TABLE 50. Analysis of variance of harvest index at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.057
0.029
Treatment 6 0.582
0.097
7.06**
3.0 4.82
Error 12
0.165
0.014
Total 20
0.803
nsnot significant CV% = 29.32
SX = 0.07
APPENDIX TABLE 51. Analysis of variance for harvest index at 90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.003
0.001
Treatment 6 0.543
0.090
10.8** 3.0
4.82
Error 12
0.107
0.009
Total 20
0.652
**Highly significant CV% = 5.83
SX = 0.05
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
105
BIOGRAPHICAL SKETCH
The author was born to Mr. Luis Kios Senior and Mrs. Gina Camolo Kios
on January 20, 1957 in Lubas, La Trinidad, Benguet.
She completed her elementary education at Lubas Elementary School at
La Trinidad, Benguet. She finished her secondary education at San Jose High
school. She continued her college education at Mountain State Agricultural
College (MSAC) and finished with a degree of Bachelor of Science in Forestry.
In 1985 she pursued her Master's degree major in Horticulture and minor in
Extension in the same school now Benguet State University (BSU) and was able
to finish in 1992.
She is presently working as a Researcher at the Northern Philippine Root
Crop Research and Training Center (NPRCRTC) based at Benguet State
University under the Crop Improvement Department.
She was a widow with three children in 1984: Denver, Donna and
Douglas Jr. and in 1989 she got married to Mr. Antonio Simongo and blessed
with one beautiful daughter Antonette.
DONITA K. SIMONGO
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
DONITA K. SIMONGO MAY 2007. Growth, yield and dry matter partitioning
of potato genotypes under organic production at La Trinidad, Benguet. Benguet State
University, La Trinidad, Benguet.
Adviser: Belinda A. Tad-awan, PhD.
ABSTRACT
The study was conducted to determine the assimilates partitioning in potato
leaves, stems, roots, stolons and tubers during the different stages of development;
compare the efficiency of potato genotypes in terms of dry matter partitioning under
organic production, and determine the best time of harvesting potatoes for optimum dry
matter accumulation.
Seven potato genotypes grown under organic production were evaluated from
November 2006 to February 2007 at La Trinidad, Benguet, and the following were
found:
Genotypes 96-06, 13.1.1 and 5.19.2.2 were the best performers in terms of
survival, vigor, canopy cover, leaf area index, net assimilation rate and crop growth rate.
Assimilates partitioned into leaves, stems, roots, stolons and tubers at 45, 60, 75
and 90 DAP differed among genotypes and at different stages of development. Among
the plant organs, the roots and stolons had the highest dry matter contents in genotype
5.19.2.2 at 45, 60 and 75 DAP. However, dry matter contents of roots, stolons, tubers
and harvest index were not affected by tem
perature, rainfall, sunshine duration and light
intensities, for all the genotypes tested. Assimilates partitioned in tubers increased in
most of the genotypes at 75 DAP and decreased at 90 DAP except in genotypes 96-06
and 5.19.2.2.
Genotypes 5.19.2.2, 13.1.1 and 96-06 had the highest total yield of 4.57, 4.21 kg.
and 4.13 kg, respectively and computed marketable yields with respective means of 6.33,
5.46 and 5.92 tons/ha.
Genotype 573275 was highly resistant to leaf miner, cv. Ganza was intermediate
and 13.1.1, 5.19.2.2, 676089 and 96-06 were moderately resistant. Genotypes 5.19.2.2,
573275, 96-06 and 13.1.1 were resistant to late blight. Cultivar Granola was susceptible
to leaf miner and late blight.
Correlation analysis revealed positive significant correlations in: plant vigor with
light intensity in genotypes 96-06, 573275, and Ganza; dry matter content of leaves with
sunshine duration in Granola; dry matter content of stems with rainfall in genotype 96-06
and with maximum temperature in genotype 573275. Significant negative correlations
were observed in: canopy cover with maximum temperature in genotype 96-06; crop
growth rate with rainfall in genotypes 13.1.1 and 5.19.2.2; and leaf area index with
minimum temperature. No significant correlation was observed in temperature, relative
humidity, rainfall, sunshine duration and light intensity with dry matter content of roots,
stolons, tubers and harvest indices in all the genotypes.
Among the characters, positive correlations in canopy cover with harvest index
and in net assimilation rate with extra large tubers were observed. Highly significant
positive correlations were observed between net assimilation rate and crop growth rate.
While several of the data gathered are conclusive, it is recommended that further
studies maybe done to verify and confirm the results, particularly in other locations and
seasons.
ii
TABLE OF CONTENTS
PAGE
BIBLIOGRAPHY ......................................................................................................i
ABSTRACT ...............................................................................................................i
TABLE OF CONTENTS ...........................................................................................iii
I. INTRODUCTION ..................................................................................................1
Background of the Study .....................................................................................1
Significance of the Study .....................................................................................2
Objectives of the Study ........................................................................................4
Time and Place of Study ......................................................................................4
II. REVIEW OF LITERATURE ..............................................................................5
Potato Growth and Development ........................................................................5
Physiology of Potato ............................................................................................7
Environmental Requirements of Potato ...............................................................8
Dry Matter Accumulation ....................................................................................10
Organic Production ..............................................................................................12
Components of Organic Production.....................................................................13
III. MATERIALS AND METHODS .........................................................................16
Treatments ...........................................................................................................16
Planting Material Preparation .............................................................................16
The Farm .............................................................................................................16
Land Preparation .................................................................................................16
Organic Fertilizer Application and Plant .............................................................16
iii
Cultural Management Practices Employed .........................................................17
Experimental Design and Treatments ..................................................................17
Data Gathered .....................................................................................................18
Meteorological Data ............................................................................................18
Soil Analysis .......................................................................................................18
A. Growth Parameters ..................................................................................18
B. Yield and Yield Parameters ....................................................................22
C. Dry Matter Parameters ............................................................................22
D. Other Data ...............................................................................................25
Analysis of Data ..................................................................................................26
IV. RESULTS AND DISCUSSION ..........................................................................28
Meteorological
Data
............................................................................................28
Soil Analysis Before Planting and After Harvest ...............................................29
Plant
Survival
......................................................................................................30
Plant
Vigor
...........................................................................................................31
Canopy
Cover
.....................................................................................................32
Leaf Area Index ..................................................................................................34
Net Assimilation Rate (NAR) .............................................................................36
Crop Growth Rate ...............................................................................................37
Yield
Component
................................................................................................38
Dry Matter Content of Leaves, Stem, Roots (roots and stolons)
and Tubers at 45, 60, 75 and 90 DAP .................................................................47
Harvest Index at 45, 60, 70 and 90 DAP ............................................................55
iv
Leaf Miner Incidence at 45, 60, 70 and 90 DAP ................................................57
Late Blight Infection at 60 and 70 DAP .............................................................58
Correlation Analysis ...........................................................................................60
V. SUMMARY CONCLUSIONS AND RECOMMENDATIONS ..........................75
VI. LITERATURE CITED ........................................................................................82
VII. APPENDICES ...................................................................................................88
VIII. BIOGRAPHICAL SKETCH ...........................................................................105
v
1
INTRODUCTION
Background of the Study
The Potato, which is locally known as "patatas" or "papas", is one of the
major crops in the Philippine highlands.
Potatoes are grown mainly in the
cool, high altitude areas with well-distributed rainfall. The most suitable
elevation is between 1,500 to 2,500 masl (Haluschak, et al. 2001). It grows best
with temperatures ranging from 17 to 22oC and a soil temperature of 15 to 18 oC.
Average relative humidity requirement is 86% (Horton, 1987). Potatoes grow
well on a wide variety of soils. However, the ideal soil for potatoes is deep, well
drained, and friable.
In the Philippines, the major potato production area is concentrated in high
elevations with a temperature below 21 oC. This temperature is suitable for
growth and development of quality potato tubers. The major potato producing
municipalities of Benguet Province are Atok, Bakun, Buguias, Kabayan,
Kibungan and Mankayan and Bauko, Mountain Province (Gayao, et al. 1999).
The potato growing areas are usually in slightly rolling terrains and most of the
growing areas like Kibungan, Mankayan and Bauko Mountain Province are rain -
fed.
Potatoes are usually grown using conventional practices such as the use of
inorganic fertilizers and chemical pesticides. In the highlands, potatoes are one of
the most chemically sprayed crops. According to Ganga et al. (1995) and Gayao
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
2
et al. (1999), fungicide control constitutes about 12% of the total production cost
and this may go higher when susceptible cultivars are planted during rainy
seasons. Excessive amounts of potentially hazardous chemicals are clearly
undesirable in a foodstuff, particularly when it is widely consumed in
comparatively large quantities, and limits of concentration may be prescribed by
the FAO/WHO or by national legislation. Adequate monitoring of residues of
such chemicals is however, difficult (Burton 1989).
An alternative to conventional production is the use of organic products.
Organic potato production prohibits the use of synthetic chemicals, fertilizers,
pesticide, growth regulators, or genetically modified varieties. Delanoy, et al.
(2003) reported that the key to successful production of potatoes without the use
of synthetic pest control products is prevention and nutritional health.
Significance of the Study
Potatoes are an important crop in the Philippine highlands and farmers
grow this conventionally. The heavy use of fertilizers and pesticides cause
problems such as soil depletion and recurrence of new pest and diseases.
Growing potatoes organically may help the soil restore its nutrients and
recurrence of pest and diseases may be reduced, and predators used will not be
destroyed. As a result, there would be sound environment, safe potatoes for food,
and higher income for farmers.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
3
As in other production systems, organic potato production may require
varieties which, have efficient dry matter accumulation and resistant to pests and
diseases. Horton (1981) reported that dry matter production per hectare is a more
meaningful yardstick for comparing crops, regardless of their use for feed, starch,
or alcohol. Measures of edible energy and protein production per hectare are
more appropriate indicators of the nutritional yield of crops consumed by humans.
In terms of dry matter production per hectare, potatoes are among the most
productive crops grown in the developing countries. Production of dry matter,
edible protein, and monetary value may be used to measure the total production of
food crops.
Dry matter content varies considerably between varieties and is a strongly
inherited characteristic. Irrespective of cultural conditions that may affect dry
matter certain varieties are consistently high in dry matter, while others are
consistently low (Toolangi, 1996).
Growers must understand how to manipulate the growth of the leaf and
root system of the potato crop so that radiation interception may be maximized
and efficiency maintained. Tuber yield vary between seasons and between fields
within seasons. Photosynthesis could be described as the process of dry matter
production combined to produce glucose – sucrose – starch (Burke, 2003).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
4
Potato plant dry matter and partitioning patterns into various part of the plant
are important to fine tune management practices that optimize tuber production
(Kanzikwera, et al, 2001).
The Objectives of the Study were to:
1. Determine the assimilates partitioning in potato leaves, stems, roots,
stolons and tubers during the different stages of development;
2. Compare the efficiency of potato genotypes in terms of dry matter
partitioning under organic production; and
3. Determine the best time of harvesting potatoes for optimum dry matter
accumulation.
Time and Place of Study:
The field trial was conducted at Balili, La Trinidad from November 2006
to February 2007 and dry matter analysis of samples was done at the Semi-
temperate Vegetable Research Development Center, BSU laboratory from March
to April 2007.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
5
REVIEW OF LITERATURE
Growth and Development of Potato
The growth of a potato plant occurs in several stages: sprout development,
plant establishment, tuber initiation, tuber bulking and tuber maturation. Timing
of these growth stages varies depending upon environmental factors, such as
elevation and temperature, soil type, availability of moisture, cultivar selected and
geographic location (Dwelle and Love, 2006).
Achieving tuber maturity is complicated. As tubers grow, develop and
mature, a peak in dry matter production occurs. A minimum amount of sugar is
achieved shortly thereafter. This stage is considered physiological maturity and is
an indicator of when to start vine-kill and harvest (Dias, 2006). In cassava early
growth is characterized by development of shoot and fibrous root and assimilate
allocation changes from shoot to root with crop age (Akparobi, et. al. 2002).
Furthermore, Dar (1981) reported that the tuber of the potato is basically
considered as a part of its stems for food storage and reproduction. The so-called
root system of the plant is an extension of the stem. Stolons emerge in the
subterranean portion of the stem from the axis of scale leaves and they carry
adventitious root system and end in the tuber. Therefore, the potato tubers may be
regarded as enlarged stolons. Also, the skins of the tubers have several lenticels
and these are considered as the stomates of the tubers.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
6
Three periods can be distinguished in the potato's growth cycle: pre-
emergence/emergence, foliage growth, and tuber growth. Foliage growth and
tuber growth may overlap for a considerable time especially in late-maturing
varieties. Stems grow from the sprouts of the seed tuber. After stems emerge
from the soil, foliage and roots develop simultaneously and their growth is
correlated. Tubers generally start growing slowly about 2 to 4 weeks after
emergence and continue growing at a fairly steady rate (Horton, 1987).
Balaki (1981) stated that the leaf is responsible in the production of CHO
to be used for tuber growth. The same report put forward that the desired leaf
area index for potato ranged from 3 to 3.5 at the bulking stage.
Burke (2003) reported that tuber yield is determined by (i) the amount of
photosynthetically active radiation intercepted by the canopy (ii) the efficiency
with which this radiation is converted to dry matter and (iii) the proportion of
accumulated dry matter partitioned to the tubers. Each of the forgoing steps may
be influenced by the grower and an understanding of their contribution to tuber
yield may help explain variation in yield observed between varieties, between
growing seasons and between fields within a growing season.
According to Dias (2006) achieving tuber maturity is complicated. As
tuber grows, develop and mature, a peak in dry matter production occurs. A
minimum amount of sugar is achieved shortly thereafter. This is important
because high dry matter and low sugar content are important for processing. This
Growth, yield and dry matter partitioning of potato genotypes under organic
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7
stage is considered physiological maturity and is an indicator of when to start
vine-kill and harvest.
Physiology of the Potato Crop
Burton (1989) reported that physiological behavior is used as an aid in
classification rather than in identification, although the time when sprouting starts,
and the rate of sprout growth, though varying from year to year and with the
origin of the tubers, may be used to distinguish between the tubers of some
varieties. The response to photoperiod may vary considerably, and is a major
point of difference between S. tuberosum sub sp. tuberosum and S. tuberosum sub
sp. Andigena. It may underlie a number of physiological differences such as time
of maturity.
The economic yield of any crop is a function of the amount of light energy
absorbed by the green foliage, the efficiency of the foliage to use the energy
captured for biomass production, and the partitioning of the crop biomass to the
harvested plant part. Because potatoes has one of the highest harvest indices of
major crops and there may be little potential for significant shifts in total biomass
accumulation, genotypes with potential for significant shifts in total biomass
accumulation, genotypes with superior net photosynthesis will likely be needed
for further yield improvement Flyn et. al. (1998) as cited by Schittenhelm et. al.
(2004).
Growth, yield and dry matter partitioning of potato genotypes under organic
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8
Environmental Requirements of Potatoes
The potato crop is grown mainly in the cool, high altitude areas with well-
distributed rainfall. The most suitable elevation is between 1,500 meters to 2,500
meters above sea level (Haluschak, et. al. 2001). The potato grows best with
temperatures ranging from 17 to 22oC and with average relative humidity
requirement of 86%. Soil temperatures of 15 to 18 oC appear to be the most
favorable for common potato varieties (Horton, 1987).
Burton (1966) reported that temperature influences the rate of both
photosynthesis and respiration, and the net effect of an increase in temperature
might range from increase to a marked decrease in yield of dry matter. The same
report further said that an optimum temperature for tuber formation and growth in
most potato varieties is about 15oC to 20oC. Engel and Raeuber (1981) likewise
found that the maximum temperature during the day is 20oC and 14oC during the
night, and Bodlaender (1963) stated that the potato requires different temperature
regimes for different stages of growth. High temperature appears to stimulate
plant growth but is unfavorable for leaf expansion. The maximum leaf weight
may be produced at 12oC to 14oC. Furthermore Hartmann et. al. as cited by
Chong et. al (2000) reported that temperature is the single most important factor
in the regulation of the timing of germination, because of its role in dormancy
control and/or release, or climatic adaptation.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
9
It has been cited that potatoes are affected by the differences in
temperature, Anon (2006). It was stated by the same source that tuberization
occurs earlier at lower temperatures, approximately 3 to 5 weeks earlier than
those in longer, warmer days. The optimal temperature for tuberization is 55oF,
the process decreases above 70oF and with certain cultivars, may stop at 85oF was
also cited by the same source. Furthermore Winkler (1969) reported that, in
general optimum conditions for high potato yields are average leaf temperature of
17 to 18 oC and average maximum air temperature of 20 to 23 oC. Likewise
Bodlaender (1963) stated that optimum temperature for stem elongation was
found to be 18 oC.
As reported by Yamachugi (1964) the soil temperature can affect tuber
development. He found that stem emergence was rapid at 21oC to 24oC and the
optimum soil temperature for tuber formation was between 15oC to 24oC. At
26oC to 29oC, tubers developed are misshapen and often, several tubers formed
single stolons. Malik and Dwelle stated further that plants accumulated more total
dry matter under cool soil (15 and 19 oC) temperatures than under hot soil (30 oC)
conditions. Soil properties, Toolangi (1996) revealed that soil pH is generally not
regarded as having a direct effect on dry matter but can affect total dry matter per
hectare by its effect on yield.
High evaporative demand caused by low relative humidity, high solar
radiation, and/or high wind speed can also reduce photosynthesis. Prolonged
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
10
periods with overcast skies can reduce light intensity to levels below that required
for maximum dry matter production (Stark et. al. 2003). Likewise Beukema and
Vander Zaag (1979) stated that light used for assimilation depends on the light
available (light intensity and daylength) and the light intensity intercepted by the
green leaves.
The optimal photoperiod for potato yields depends upon temperature and
cultivar, such that Andigena cultivars fail to tuberize unless they have received
short days (Simmonds 1964). Furthermore Marique (undated), reported that the
shorter the photoperiod, the greater the percentage of plant biomass that is
partitioned to tuberosum cultivars, especially those that are early maturing, which
may perform poorly under cool tropical conditions because tuber induction is
excessively strong. The same report claims that the result of excessively strong
induction is that haulm and root growth are so restricted by the strong partitioning
of dry matter to tubers that the leaf area is too small to support good tuber yields.
Cooper and Fox (1996) stated that the relative performance of genotypes
changes across environments, thus most breeding programs conduct multi-
environment trials to evaluate genotypic adaptation over a sample of
environments from the target population.
Dry Matter Accumulation
According to Horton (1987) the length of a potato variety's growth cycle is
influenced by environmental conditions, so that a variety that is late under one set
Growth, yield and dry matter partitioning of potato genotypes under organic
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11
of growing conditions can be early under another. Likewise DPI (2006) and
Toolangi (1996) reported that dry matter content varies considerably between
varieties and is a strongly inherited characteristic. As reported, irrespective of
cultural condition that can affect dry matter certain varieties are consistently high
in dry matter, while others are consistently low.
According to Kanzikwera et. al. (2001) potato plant dry matter and
partitioning pattern into various parts of the plant are important to fine tune
management practices that optimize tuber production. The same source stated that
dry matter production per hectare is a more meaningful yardstick for comparing
crops, regardless of their use for feed, starch, or alcohol, and measures of edible
energy and protein production per hectare are more appropriate indicators of the
nutritional yield of crops consumed by humans. In terms of dry matter production
per hectare, potatoes are among the most productive crops grown in the
developing countries; and production of dry matter, edible protein, and monetary
value can be used to measure the total production of food crops (Horton, 1987).
Two useful terms used to describe partitioning of dry matter by plants are
biological yield and economic yield. The term biological yield was proposed by
Nichiporovich (1960) to represent the total dry matter accumulation of a plant's
system. Economic yield and agricultural yield have been used to refer to the
volume or weight of those plant organs that constitute the product of economic or
agricultural value. The proportion of biological yield represented by economic
Growth, yield and dry matter partitioning of potato genotypes under organic
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12
yield has been called harvest index, the coefficient of effectiveness, or the
migration coefficient (Gardner, et al, 1985).
Initially, dry matter is divided between stems and leaves (growth stage II).
In the second phase, which starts at tuber initiation, an increasing amount of
accumulated dry matter is allocated to the tubers and decreasing fraction to leaves
(growth stages III and IV). In the third phase all assimilates are allocated to the
tubers (growth stage V) (Pereira and Shock, 2008).
Organic Production
Organic production is designed to work with natural processes to conserve
resources, encourage self-regulation through diversity, and minimize waste and
environmental impact, while preserving farm profitability. Such systems aim to
produce food that is nutritious and uncontaminated with substances that could
harm human health (Edward-Jones and Howells, 2000).
Organically grown crops produce consistently tests product higher than
non-organically grown foods for vitamins, minerals, and other micronutrients, as
well as showing much smaller amounts of nitrates, heavy metals and other
contaminants. One of the main reasons for this nutritional discrepancy is that
organic soil is much richer in minerals and micronutrients than non-organic soil
(Anon, 2005).
The various source further stated that plants grown on healthy soil are less
susceptible to pests and so; the need for pest eradication is reduced. Chemical-
Growth, yield and dry matter partitioning of potato genotypes under organic
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13
based agriculture however, begins with soil which is already nutrient depleted;
that plants grown on depleted soil are weaker and more prone to disease and
pests, so more chemicals are needed every year.
An ample supply of decaying organic matter helps to keep the soil loose
and mellow and thus reduces soil compaction. Potato tubers develop and maintain
normal shape better in loose, well-aerated soils. Organic matter facilitates plowing
and cultivating; it enables roots of potato plants to penetrate the soil more readily,
and it improves water retention; it provides food energy for the growth of
desirable soil micro-organisms and supplies plant nutrients (Anon, 2006).
Components of Organic Production
Use of Organic Fertilizers
Horton (1987) reported that organic fertilizer improves the soil structure
and increase the moisture retention capacity. Davis and Wilson (2002) likewise
stated that the application of organic soil amendments increase soil organic matter
content and offer many benefits such as: it improves soil aeration, root infiltration
and both water and nutrient holding capacities and act as organic fertilizer, and
pants that absorb the nutrients in the soil can tolerate damage caused by soil
pathogens.
The importance of organic matter are: source of nutrients; improves CEC
of the soil-high CEC protects available and exchangeable cation from leaching;
Growth, yield and dry matter partitioning of potato genotypes under organic
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14
source of humus; decomposition products such as organic acids help dissolve
minerals and insoluble phosphates and it improves water-holding porosity,
aeration and aggregation of the soil, thus improving soil environment for normal
root growth (Balaki, 1981).
On the other hand, according to the Philippine Council for Agricultural
Resources Research and Development (PCARRD, 1982), the literal application of
soil organic fertilizers supply an amount of nutrient requirements of the
granulation, and easy root penetration. On the other hand, Korva and Varis
(1990); Haraldsen et al. (2000) as cited by Delden (2001) reported that smaller
arable crop yields in organic farming systems compared with those from
conventional practices have been attributed to a mismatch between N supply and
demand. Thus, in organic farming, the limited amounts of available N require
more effective distribution among the various crops optimizes farm results.
It has been reported that: Potash and phosphorous will need to be provided
in the form of composted farmyard manure; that if this is not available from an
organic source then it can be brought in and composted on the farm for a period of
three months prior to use. And that depending on the natural fertility of the soil
manure is generally spread at a rate of 30 - 35 t/ha (Western Potato Council,
2003).
Diversity in crop production. The farm should have sufficient crop
diversity in time and/or space that takes into account pressures from insect,
Growth, yield and dry matter partitioning of potato genotypes under organic
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15
weeds, diseases and other pests while maintaining or increasing soil organic
matter, soil fertility, microbial activity and general soil health (Anon, 2003).
Choice of crops and varieties. Species and varieties cultivated should, as
far as possible, be adapted to the soil and climatic conditions and should be
resistant to pests and diseases; and that all seeds and plant materials used should
be from certified organic produce or from the same farm (Anon, 2003).
Growth, yield and dry matter partitioning of potato genotypes under organic
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16
MATERIALS AND METHODS
Treatments
Seven potato genotypes selected from previous evaluations under organic
production were grown at Balili La Trinidad with an elevation of 1,300 m asl.
Planting Material Preparation
The planting materials from the seven potato genotypes were secured from
Cabutotan, Bakun where organic production practices were followed.
The Farm
The land used was transitioned to organic production four years ago.
Rotations of crops such as beans, potato, and beans were practiced. The land was
fallowed for at least three months before the cropping season from March to
October. Corn was planted on the borders of the farm to serve as barrier while
marigold was planted in between beds to serve as pest repellants.
Land Preparation
The area was first cleared of weeds and prepared using a tractor. Plots
were prepared measuring 1m wide x 5m long.
Organic Fertilizer Application and Planting
Compost at a rate of 10kg/5m2 was evenly incorporated with the soil one
month before planting.
Growth, yield and dry matter partitioning of potato genotypes under organic
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17
Sprouted tuberlets of the different potato genotypes and cultivars were
used as planting materials. Forty seed tubers of each genotype and culitvar were
planted at a distance of 30 cm between hills and 20 cm between rows.
Cultural Management Practices Employed
Irrigation was done twice a week using a water pump with hose. Pests and
diseases were controlled through the integration of mixed cropping, planting of
repellant crops such as marigold, use of yellow traps and application of bio-
fungicide (Bacillus subtilis).
Experimental Design and Treatments
The experiment was laid out following the randomized complete block
design (RCBD) with three replications. Each block was subdivided into 7 plots
measuring 1m x 5m. The use of the term cultivar (cultivated variety) or cv. In
short is appropriate, technologically.
Treatment Genotype
Code/Cultivar Source
V1
13.1.1
CIP, Peru
V2
96-06
CIP, Peru
V3 573275
CIP,
Peru
V4
5.19.2.2
Philippines
V5 676089
CIP,
Peru
Growth, yield and dry matter partitioning of potato genotypes under organic
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V6
Ganza
CIP, Peru
V7
Granola
Germany
Data Gathered:
Destructive sampling was done at 30, 45, 60, 75 days after planting (DAP)
to obtain the dry mass of the leaves, stems, roots, stolons and tubers. Plate 1
shows the different genotypes at 60 DAP.
Meteorological Data
Meteorological data such as air temperature, relative humidity, rainfall
amount and sunshine duration was taken at the BSU-PAG-ASA records. Light
intensity was taken weekly using the light intensity meter.
Soil Analysis
Soil samples were obtained before and after planting and brought to the
Soils Laboratory at Pacdal, Baguio City for analysis.
A. Growth Parameters
1. Percent Survival. Percent survival was taken at 30 DAP by counting the
number of plants that survived and computed using the formula:
No of plants that survived
% Survival = _____________________ x 100
Total no. of plants planted
Growth, yield and dry matter partitioning of potato genotypes under organic
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2. Plant Vigor. This was recorded at 30, 45, and 60 (DAP) using the
following rating scale by Palomar and Sanico, 1994.
Scale
Description
Reaction
5
Plants are strong with robust stems and Highly vigorous
leaves; light to dark green in color
4
Plants are moderately strong with robust Moderately
stems and leaves; light green in color.
vigorous
3
Plants are better than less vigorous
Vigorous
2
Plants are weak with few thin stems and Less vigorous
leaves; pale
1
Plants are weak with few stems and leaves; Poor vigor
very pale.
3. Canopy Cover. A hand - made grid with a wooden frame and a threaded wire
was used. A marker was placed at the center of four sample plants at random per
replication, and then the grid was placed against the marker. Canopy cover was
taken at 30, 45, 60 and 75 DAP.
4. Leaf Area Index (LAI). The leaf area of two sample plants was collected at
45, 60 and 75 dap. Two green leaves from the lower, middle and upper parts
were considered from the sample plants using the Tracing Technique method by
Saupe (2006). This compares a paper replica of the surface to be measured to a
standard of known area.
Growth, yield and dry matter partitioning of potato genotypes under organic
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Leaf area (mm2) = weight of leaf tracing (g) x conversion factor (mm2 gm-1)
Leaf area (mm2)
Leaf area Index (LAI) = _________________
Ground area (mm2)
Note: The leaf area was determined by multiplying the leaf area per leaf
to the total number of leaves per plant.
5. Net Assimilation Rate (NAR). This is the dry matter accumulation rate per
unit of leaf area per unit of time and was taken following the formula by Fitter
and Hay, 1981:
NAR g / m-2/d = lnW2 – lnW1 x (La)
T2 – T1
Where:
L
A = Leaf area
W = Weight
T = Time (days)
6. Crop Growth Rate. This was computed following the formula by Gardner,
1985:
CGR = (NAR) x (LAI)
Growth, yield and dry matter partitioning of potato genotypes under organic
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21
13.1.1
96-06
A B
573275
5.19.2.2
C
D
676089
Ganza
Granola
G E F
Plate 1. The genotypes and cultivars sampled at 60 DAP.
Growth, yield and dry matter partitioning of potato genotypes under organic
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22
B. Yield and Yield Components
1. Tuber Yield Parameters
a. Number and weight of marketable tubers per plot (kg). All tubers
of marketable quality (small, medium, extra and large) were
counted and weighed.
b. Number and weight of non-marketable tubers per plot (kg). These
were the tubers that are malformed, damaged by insects and
diseases and those with more than 10% greening.
c. Total yield per plot. This is the sum of weight of marketable and
non-marketable tubers per plot.
d. Computed yield (t/ha). This was computed following the formula.
Total marketable yield/plot x 10,000 m2
Yield (kg) = ___________________________________
5m2
Yield (tons/ha) = Yield (kg)
1000
C. Dry Matter Parameters
At 45, 60, and 75 DAP, destructive sampling was done to determine the
dry matter partitioned in the leaves, stems, roots, stolons and tubers. Samples of
the leaves, stems, roots, stolons and tubers were separated and weighed, packed in
brown paper bag labeled properly and placed in the oven just after arriving from
Growth, yield and dry matter partitioning of potato genotypes under organic
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23
the field to the laboratory. The oven was set at 80oC. After 56 hours the dry
weight was taken.
1. % Dry Matter Content of Leaves, Stems, Roots, Stolons and Tubers.
Plate 2 presents the procedure in determining the dry matter of the
different genotypes and cultivars.
Dry matter content of the leaves, stems, roots, stolons and tubers were
obtained by the following formula:
%DMC = 100 – MC
Where: %MC = Fresh weight – Oven dry weight x 100
Fresh weight
2. Harvest Index (%)
Harvest Index is the ratio of the economic yield to biological yield, which
is expressed as:
% HI = TDW x 100
LDW + SDW + RSDW
Where:
TDW = Tuber dry weight
RSDW = root and stolons dry weight
LDW = leaf dry weight
SDW = Stem dry weight
Growth, yield and dry matter partitioning of potato genotypes under organic
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Separation of leaves, stems, roots, Slicing of potato tubers into cubes
stolons and tubers
Weighing of potato tubers Weighing of potato leaves
Weighing of potato stems Oven drying of the leaves, stems,
roots, stolons and tubers
Plate 2. Procedure in dry matter determination of the different genotypes and
cultivars.
Growth, yield and dry matter partitioning of potato genotypes under organic
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25
D. Other Data
1. Leaf Miner Incidence
The appearance of insect pest was observed during the growth stage of
the plant using the following scale (CIP, 2001):
SCALE DESCRIPTION
1 No apparent injury
2
Injury confined to youngest leaves
3
Some older leaves exhibiting injury
4
Over 50 % of the leaves injured
5
Over 90 % of the leaves injured
2. Late Blight Infection
Late blight was observed during the growth stage of the plant at 60 and 75
DAP using the CIP rating scale (Henfling, 1987):
Growth, yield and dry matter partitioning of potato genotypes under organic
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26
CIP
Blight (%)
scale
value
Mean limit
Symptoms
1
0
No late blight observable
2
2.5
Traces -< 5
Late blight present. Maximum 10 lesions per plant
3
10
5 -< 15
Plants look healthy, but lesions are easily seen at
closer distance. Maximum foliage area affected by
lesions or destroyed corresponds to no more than
20 leaflets.
4
25
15 -< 35
Late blight easily seen on most plants. About 25%
of foliages is covered with lesions or destroyed.
5
50
35 -< 65
Plot looks green; however, all plants are affected.
Lower leaves are dead. About half the foliage area
is destroyed.
6
75
65 -< 85
Plots look green with brown flecks. About 75% of
each plant is affected. Leaves of the lower half of
plants are destroyed.
7
90
85 -< 95
Plot neither predominantly green nor brown. Only
top leaves are green. Many stems have large
lesions.
8
97.5
95 -< 100
Plot is brown-colored. A few top leaves still have
some green areas. Most stems have lesions or are
dead.
9
100
All leaves and stems dead.
The description of symptoms is based on plants with 4 stems and 10 to 12 leaves
per stem.
Analysis of Data
The data was analyzed through analysis of variance in RCBD except for
leaf miner and late blight. Significance among treatment means was analyzed
using the Duncan's multiple Range Test (DMRT). Correlation analysis was also
done.
Growth, yield and dry matter partitioning of potato genotypes under organic
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27
According to Amid (2005), the degree of relationship between two
variables can be measured using the Pearson product moment correlation
coefficient (R) which characterizes the independence of X and Y. The coefficient
R is a parameter, which can be estimated from sample data using the formula:
NΣxy – (Σx)( Σy)
R = _______________________________
[n Σx2 – (Σx)2] [n (Σy ) – (Σy)2]
Growth, yield and dry matter partitioning of potato genotypes under organic
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RESULTS AND DISCUSSION
Meteorological Data
The minimum and maximum air temperature during the study period
ranged from 12.6 to 15.6 oC and 23.5 to 24.2 oC, respectively while relative
humidity ranged from 77 to 80 % (Table 1). Horton (1987) stressed that potato
grows best with temperature ranging from 17 to 22 oC and with an average
relative humidity of 86%. Temperature and relative humidity during the conduct
of the study were observed to be appropriate for potato production. A very little
rainfall of 2.5, 2.4 and 0.05 mm was recorded in November, December and
January, respectively. Sunshine duration in the month of November, December
and January was low ranging from 386.6 to 381.4 mm as compared to the
sunshine duration in February, which is 521.6 mm (Table 1). Light intensity was
observed to be low from November to January with December having the lowest
light intensity of 45.1 Klux while February had the highest light intensity with
76.4 Klux.
Growth, yield and dry matter partitioning of potato genotypes under organic
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29
Table 1. Meteorological data from November 2006 to February 2007.
AIR TEMP. (oC) RELATIVE RAIN-
SUNSHINE
LIGHT
HUMIDITY
FALL
DURATION INTENS-
MONTH
MIN
MAX
(%)
AMT.
(mm)
ITY*
(mm)
(Klux)
Nov.
15.2
23.5
80
2.5
381.4
57.2
Dec.
15.6
24.2
78
2.4
387.0
45.1
Jan.
13.9
23.9
77
0.03
386.6
58.9
Feb.
12.6
23.6
77
0
521.6
76.4
Soil Analysis Before Planting and After Harvesting
Results of the analysis revealed that soil pH before planting was 6.72 and
slightly decreased to 6.31 after harvest (Table 2). Organic matter, phosphorus,
potassium and nitrogen increased. The increase in the organic matter,
phosphorus, potassium and nitrogen was probably due to the application of
compost hilled-up at 30 DAP. Smilde (undated) reported that the decomposing
humus is a slow-release source of nutrients to plants and carbon to
microorganisms. The same report stated that crops with shallow root system like
potatoes might absorb only the partially released nutrients from the fertilizer
applied. Furthermore, Colting (1981) pointed out the following: that organic
residues with narrow C:N ratio (i. e. legumes), take longer time to decompose.
That, long term benefits are derived from fully decomposed residues with wide
C:N ratio. That organic matter with C:N ratio higher than 30 usually immobilizes
Growth, yield and dry matter partitioning of potato genotypes under organic
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30
N at the earlier stage of decomposition. Examples of C:N ratios used in the
Colting report were: cereal straw (C:N ratio = 80); green manure (C:N ratio = 20);
stable organic matter (C:N ratio = 110-120).
Table 2. Soil analysis before planting and after harvesting.
SOIL PROPERTY
BEFORE PLANTING
AFTER HARVEST
PH
6.72
6.31
Organic matter (%)
2.50
4.50
Nitrogen
0.13
0.23
Phosphorus (ppm)
90
140
Potassium (ppm)
312
341
Plant Survival
Table 3 shows significant differences on the percent plant survival among
the seven genotypes evaluated at 30 DAP. Genotype 13.1.1 significantly had the
highest plant survival of 98 % followed by 5.19.2.2 with plant survival of 97 %.
The rest of the genotypes had plant survivals ranging from 30 to 85 %. The
variability of the plant survival rate as found in the study was mainly affected by
their sprouting ability as exhibited by their genetic characteristics affected by the
environmental factors prevailing during the conduct of the trial.
Growth, yield and dry matter partitioning of potato genotypes under organic
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31
Table 3. Percent survival of seven potato genotypes grown at La Trinidad
under organic production.
GENOTYPE PLANT
SURVIVAL
(%)
13.1.1
98a
96-06
85a
573275
30b
5.19.2.2
97a
676089
75a
GANZA
74a
GRANOLA
50b
CV (%)
17.73
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Plant Vigor
The plant vigor at 30, 45, and 60 DAP of the seven genotypes is shown in
Table 4. Genotypes 13.1.1 and 5.19.2.2 significantly exhibited highly vigorous
growth at 30, 45, and 60 DAP. Genotype 573275 had moderate vigor at 30 DAP
but recovered at 45 and 60 DAP. Cultivar Granola had moderate vigor rates at 30
and 45 DAP and less vigorous at 60 DAP. The variation on plant vigor among
the genotypes evaluated may be due to their genetic characteristics as affected by
the environmental factor prevailing during the study period.
Growth, yield and dry matter partitioning of potato genotypes under organic
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32
Table 4. Plant vigor of seven potato genotypes Grown at La Trinidad under
organic production.
GENOTYPE
PLANT VIGOR
30 DAP
45 DAP
60 DAP
13.1.1
5a
5a
5a
96-06
4b
5a
5a
573275
3c
4b
4b
5.19.2.2
5a
5a
5a
676089
4b
4b
5a
GANZA
4b
5a
5a
GRANOLA
3c
3c
2c
CV (%)
8.82
6.50
6.50
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Rating Scale:
5 = Highly vigorous
4 = Moderately vigorous
3 = Vigorous
2 = Less vigorous
1 = Poor vigor
Canopy Cover
Significant differences on the canopy cover at 30, 45, 60 and 75 DAP was
observed among the seven genotypes (Figure 1).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
33
All the genotypes showed an increasing canopy cover from 30 to 60 DAP
but decreased at 75 DAP. Genotype 96-06 significantly had the highest canopy
cover followed by genotypes 5.19.2.2 and 13.1.1. At 60 DAP genotype 5.19.2.2
significantly had the highest canopy cover followed by that of 96-06 and 13.1.1.
Cultivar Granola had the lowest canopy cover at 30 up to 60 DAP. The canopy
cover differed among genotypes, which may be attributed by their inherent
characteristics. Amer and Hatfield (2004) reported that the peak of leaf area is
chiefly influenced by variety, fertilizer and planting date.
One of the environmental factors that affected the vegetative growth may
be light intensity. The light intensity was low from November to February
ranging from 57.2 to 58.9 Klux and increased to 76.4 Klux from the month of
January. This conforms with the report of Dar (1981) that at lower light
intensities, haulm growth is stimulated and tuber growth is delayed. Furthermore,
the same author put forward that some of the genotypes started to senesce while
others was early attacked with leaf miner, thus the lower leaves fall of resulting to
lower canopy. Amer and Hatfield (2004) also reported that leaf area decreased
during the maturity stage because of senescing leaves in the lower part of the
canopy.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
34
60
a
a
a
50
a
a
13.1.1
ab ab
a
a
40
96-06
a
ab
a
573275
a
a
a
b
30
ab
b
a
5.19.2.2
bc
676089
20
b
Canopy Cover
bc
Ganza
c
cd
10
Granola
c
c
d
0
c
30
45
60
75
Days ater planting
Figure 1. Canopy cover of seven potato genotypes grown at La Trinidad under
organic production.
Leaf Area Index
All the genotypes had increased in their leaf area indices at 60 DAP but at
75 DAP, some genotypes of which had decreased while the others increased
(Figure 2).
Genotype 5.19.2.2 significantly had the highest leaf area index at 45 DAP
followed by genotypes 96-06 and 13.1.1 while genotypes 573275 and cv. Granola
had the lowest leaf area indices. At 65 DAP all the genotypes increased in their
leaf area indices with genotype 5.19.2.2 showing the significantly highest
followed by 96-06 and 697089, while cv. Granola had the lowest leaf area index.
Genotypes 5.19.2.2, 676089, 573275 and cv. Ganza showed an increasing
leaf area indices at 75 DAP while genotypes 96-06, 13.1.1 and cv. Granola had a
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
35
decreased leaf area index at 75 DAP (Figure 2). The decrease in the leaf area
indices was possibly due to the falling down of leaves. The falling of leaves
during the study was due to the leaf miner infestation and senescence. Amer and
Hatfield, (2004) reported that leaf area decreased at maturity stage because of
senescing leaves in the lower part of the canopy. However in the case of cv.
Granola decrease in leaf area index at 75 DAP was observe to be caused by leaf
miner infestation and late blight infection.
Significant variability of leaf area index among the genotypes evaluated
may be attributed to their genetic characteristics as influenced by these factors and
other factors such as insect and disease infection.
5
a
a
4.5
a
ab
4
13.1.1
b
3.5
96-06
a
bc
3
bc
573275
cd
2.5
b
ab
5.19.2.2
2
abc
de
676089
1.5
c
Ganza
Leaf Area Index
ef
bcd
1
bcd
Granola
cd
0.5
f
d
0
d
45
60
75
Days After Planting
Figure 2. Leaf area index of seven potato genotypes grown at La
Trinidad under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
36
Net Assimilation Rate (NAR)
Net assimilation rate or the dry matter accumulation rate per unit leaf area
is one of the useful parameters on growth analysis, which influence the increase in
plant weight per unit area of assimilatory tissue (usually leaf area: AL) per unit of
time (Fitter and Hay, 1981).
Net assimilation rate of the seven genotypes at 45, 60 and 75 DAP are
presented in Figure 3. On the other hand, results showed no significant
differences among the genotypes on their net assimilation rate at 45 and 75 DAP.
Also, statistical analyses showed significant differences on the net assimilation
rates of all the genotypes tested at 60 DAP.
All the genotypes showed an increasing net assimilation rate at 60 DAP
except for cultivar Granola. Genotype 5.19.2.2 significantly had the highest net
assimilation rate at 45 up to 75 DAP. Genotypes 676089 had the second highest
net assimilation rate at 60 DAP followed by genotypes 96-06 and cv. Ganza. At
75 DAP, it was observed that genotypes 676089, 96-06, 573275 and 13.1.1
increased in their net assimilation rate except for cultivars Ganza and Granola.
Results showed that genotypes 676089, 96-06, 573275 and 13.1.1 had an
increased dry weight accumulation per unit area of assimilatory per unit of time.
The increase in the net assimilates may be due to the biological dry biomass or
economic dry biomass of genotypes. The increased or decreased net assimilation
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
37
rate among the genotypes tested may have been affected mainly by their inherent
characteristic.
16.00
14.00
a
12.00
13.1.1
96-06
10.00
b
573275
8.00
b
5.19.2.2
b
676089
6.00
bc
Ganza
bc
4.00
Net Assimilation Rate
Granola
2.00
c
0.00
45
60
75
Days After Planting
Figure 3. Net assimilation rate of seven potato genotypes grown at La
Trinidad under organic production.
Crop Growth Rate
The crop growth rates of different genotypes evaluated during the study
are shown in Figure 4. Crop growth rate is the dry matter accumulation percent of
land area per unit of time (Gardner et. al. 1985).
Figure 4 showed an increasing crop growth rates from all the genotypes at
60 DAP except in cv. Granola. Genotype 5.19.2.2 significantly had the highest
crop growth rate at 45 to 65 DAP while cv. Granola was the lowest. At 75 DAP
genotype 676089 significantly increased in its growth rate while genotypes
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
38
573275 and cv. Ganza had little increase. On the other hand, Genotypes 5.19.2.2,
96-06 and 13.1.1 showed decreasing growth rates, which indicate that these
genotypes had attained their maturity period. On the other hand, genotypes
676089 and 573275 were still accumulating dry matter, which indicate that these
genotypes had longer period of maturity.
70.00
60.00
a
13.1.1
50.00
a
96-06
573275
40.00
ab
5.19.2.2
a
30.00
676089
b
bc
bc
20.00
Ganza
Crop Growth Rate
bc
b
bc
Granola
bc bc
c
10.00
bc bc
c
c
c
c
0.00
c
c
45
60
75
Days After Planting
Figure 4. Crop growth rate of seven potato genotypes grown at
La Trinidad under organic production.
Yield Components
At harvest, the yield was classified according to sizes as prescribed. The
classified tubers were counted, weighed and recorded. Extra large tubers had an
average weight of 100 to 150 g, large tubers had an average weight of 50 to 99 g,
medium tubers had an average weight of 26 to 49 g, small tuber had an average
weight of 10 to 25 g and marble tubers had an average weight of 3 to 9 g. Non-
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
39
marketable tubers are the smallest size, rotten, and had more than 10% damage
and greening.
Number of Marketable Tubers According to Size/Plot
Extra Large Tubers. Table 5 shows the number of marketable tubers
according to size per plot of the seven genotypes evaluated. Significant
differences were observed among the treatments on the number of extra large
tubers. Genotype 13.1.1 significantly produced the most tubers while cv. Granola
produced no extra large tubers. The rest of the extra large tubers ranged from 4 to
7.
Large Tubers. The genotypes significantly differed in their mean number
of large tubers (Table 5). Genotype 13.1.1 significantly produced the most tubers
32. Cultivars Ganza and Granola, produced 6 and 0 tubers, respectively. The rest
of the genotypes produced 11 to 14 large tubers.
Medium Tubers. No significant differences were observed among the
treatment means on the number of medium tubers (Table 5). Genotype 13.1.1
produced the highest number of medium tubers with 41 while cv. Granola had no
medium tubers (Table 5).
Small Tubers. The number of small tubers was significantly different
among the seven genotypes evaluated (Table 5). Genotype 13.1.1 significantly
produced the highest number of small tubers (26) while cultivar Granola had the
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
40
least (5). The rest of the entries produced numbers of small tubers ranging from 8
to 17.
Non-marketable Tubers
Table 5 shows the number of non-marketable tubers of the different
genotypes evaluated. Among the genotypes evaluated, no significant differences
were noted on the number of non-marketable tubers.
Table 5. Number of marketable (extra large, large, medium, small and marble)
and non Marketable tubers of seven potato genotypes grown at La
Trinidad under organic production.
NUMBER OF
GENOTYPE
NUMBER OF MARKETABLE TUBERS
NON-
Extra- Large Medium Small Marble
MARKETABLE
large
TUBERS
13.1.1
10a
32a
41
26a
26
19
96-06
7ab
14b
29
17ab
19
31
573275
4bc
11bc
25
8b
7
18
5.19.2.2
7ab
14b
30
14b
23
17
676089
4bc
11bc
28
11b
12
22
GANZA
6ab
12bc
17
14b
15
21
GRANOLA
0c
0c
0
5b
4
11
CV (%)
26.32 20.95
27.28
17.07
25.66
28.45
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
41
Weight of Marketable Tubers According to Size/Plot
Extra Large Tubers. Table 6 shows the weight of tubers. The genotypes
evaluated significantly differed in their mean weights of extra large tubers.
Genotype 5.19.2.2 significantly outranked the cultivars Ganza and Granola with
weights of 0.83, 0.47 and 0 kg, respectively. The rest of the genotypes produced
weights ranging from 0.32 to 0.65 kg.
Large Tubers. Significant differences among treatment means of the
genotypes evaluated produced large tuber weights (Table 6). Genotype 13.1.1
significantly had the highest tuber weight of 1.52 kg followed by genotype
5.19.2.2 (1.05 kg). The cultivar Granola had no large tuber. The rest of the
genotypes had weights ranging from 0.63 to 0.84 kg.
Medium Tubers. Statistical analysis showed significant differences among
the medium mean weights of the seven genotypes (Table 6). Genotype 5.19.2.2
significantly had the highest mean weight of 1.39 followed by 96-06, 676089 and
13.1.1 with mean weights of 1.29, 1.27 and 1.22 kg, respectively. The least was
produced by genotype 573275 with mean weight of 0.59 kg while cv. Granola had
no medium tubers.
Small Tubers. Table 6 showed no significant differences among the treatment
means of small weight tubers. The tubers weighed from 0.04 to 1.04 kg.
Marble Tubers. Mean weights of marble tubers revealed no significant
differences among treatment means of the genotypes evaluated (Table 6).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
42
Non-marketable Tubers
Table 6 shows the weight of non-marketable tubers of the different
genotypes evaluated. Among the genotypes evaluated, no significant differences
were noted on the weight of non-marketable tubers.
Table 6. Weight of marketable (extra large, large, medium, small and marble)
and non-marketable tubers of seven potato genotypes grown at
La Trinidad under organic production.
WEIGHT OF
GENOTYPE
WEIGHT OF MARKETABLE TUBERS
NON-
Extra-
Large Medium Small Marble
MARKETABLE
large
TUBERS
13.1.1
0.65ab
1.52a
1.22a
0.42
0.35
0.09
96-06
0.65ab
0.84b
1.29a
1.04
0.27
0.12
573275
0.33b
0.59bc
0.29b
0.20
0.07
0.123
5.19.2.2
0.83a
1.05ab
1.39a
0.79
0.4
0.05
676089
0.32b
0.63b
1.27a
0.7
0.1
0.07
GANZA
0.47b
0.69b
0.61ab
0.7
0.16
0.08
GRANOLA
0c
0c
0b
0.04
0.03
0.03
CV (%)
8.93
12.97
16.56
22.17
16.32
4.95
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Total Yield
The mean total yield of the seven genotypes evaluated at La Trinidad,
Benguet under organic production are shown in Table 7, while Plate number 3
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
43
shows tubers harvested from the different genotypes and cultivars. Significant
differences were observed among the genotypes evaluated. Genotype 5.19.2.2
significantly produced the highest total mean yield of 4.57 kg followed by
genotypes 96-06 and 13.1.1 with respective mean total weights of 4.21 and 4.13
kg. The rest of the genotypes produced yield ranging from 0.067 to 2.67 kg.
Results showed low mean yields. This may be attributed to the growth
performance of the genotypes affected by environmental factors. Ivins and
Bremner, (1964) pointed out that to attain high yield in the tropics, a fast
bulking rate and longer bulking period are necessary. Earlier results showed that
the leaf area indices of the genotypes evaluated were lower and higher than the
desired leaf area index of potato, which ranged from 3 to 3.5 at the tuber bulking
stage. According to Kleinkopt, et al (2007) canopies with leaf area indices
greater than 3 to 3.5 are limited by sunlight duration and will not have greater
bulking rates than crops with normal range of leaf area index. Cultivar Granola
was the lowest yielder among the genotypes. This may be attributed to its slow
growth as shown by its low canopy cover, leaf area index, net assimilation rate
and crop growth rate. The same genotype was also attacked with leaf miner and
with late blight as early as 60 DAP which increased rapidly causing early senesce.
This shows that cultivar Granola may not be adapted for organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
44
A
B
C
D
E
F
G
Plate 3. Tubers harvested from the potato genotypes and cultivars.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
45
Computed Marketable Yield
The computed yield in t/ha (Table 7) of the seven genotypes evaluated at
La Trinidad under organic production. Significant variations on the computed
mean yield among the genotypes evaluated were observed.
Genotype 5.19.2.2 significantly had the highest computed marketable
mean yield of 6.33 tons/ha followed by genotypes 13.1.1 and 96-06 with
computed marketable mean yields of 5.72 and 5.46 tons/ha, respectively. The
three genotypes significantly outyielded the check cultivars Ganza and Granola.
The high yielding genotypes were observed to have developed wider canopies as
early as 30 DAP and this continued to increase at 60 DAP but slightly decreased
at 75 DAP. The low yielding genotypes had low canopy covers at 30 DAP which
slowly developed at 75 DAP. Cultivar Granola produced few small leaves and
thin stems, thus, solar radiation was limited resulting to decreased photosynthesis,
thus, lesser assimilates diverted into the tubers. This genotype was also infected
by leaf miner as early as 45 DAP and by late blight at 60 DAP which resulted to
its early senesce. As reported by Dwelle and Love (2006), larger canopy intercept
higher solar radiation, which increased photosynthesis diverting more assimilates
into the tubers during bulking stage resulting to higher yield.
Results showed that genotypes 5.19.2.2, 96-06, and 13.1.1 significantly
produced the highest yield of 6.33, 5.92 and 5.46 tons/ha, respectively. Though
the yield was low, these genotypes were the most adapted under organic
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
46
production at La Trinidad condition. According to Molitas (2005) the usual yield
of potato per hectare in the highlands ranged from 20 - 25 t/ha under conventional
production. The low yield obtained under organic production may be attributed
with the slow growth of the plants as shown by low canopy, leaf area index, net
assimilation rate and crop growth rate. As reported by Burton (1979),
assimilation rates of crops may reach an optimal of 100% if the total soil surface
is covered with green leaves. Likewise, Monteith (1979) stressed that crop
growth rates should be proportional to the rate of photosynthesis, which depends
on the amount of intercepted solar radiation by foliage. The low yield may also
be attributed to the transitional state of the farm used in the study. According to
Anon (2003), the establishment of an organic management system and building of
soil fertility requires an interim period, the conversion period. The same report
put forward that general rule indicates that the first two complete years of
cultivation under control will be considered in transition or in conversion. During
this stage, a decrease in yield is expected.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
47
Table 7. Total yield and computed yield of seven potato genotypes grown at
La Trinidad under organic production.
GENOTYPE TOTAL
YIELD/PLOT
COMPUTED YIELD
(kg)
(tons/ha)
13.1.1
4.13a
5.92a
96-06
4.21a
5.46ab
573275
1.54b
2.72c
5.19.2.2
4.57a
6.33a
676089
2.67b
4.28abc
GANZA
2.47b
3.42bc
GRANOLA
0.067c
0.11d
CV (%)
26.70
29.13
For each column, treatment means with different letter are significantly different
at 5% probability levels (DMRT).
Dry Matter Contents of Leaves, Stems, Root, stolons and Tubers of the Seven
Potato Genotypes at 45, 60, 75 and 90DAP
Dry matter partitioning in leaves, stems, roots, stolons and tubers of seven
genotypes at 45, DAP is presented in Figure 5.
At 45 DAP, the roots and stolons had the highest dry matter partitioned in
genotypes 5.19.2.2, 13.1.1, 676089 and 96-06 (Figure 5). The tubers partitioned
the second highest dry matter in genotypes 5.19.2.2, 96-06 and 13.1.1. The stems
partitioned had the lowest in genotypes 573275 and 96-06 followed by the dry
matter partitioned into the leaves in genotypes 573275 and 676089.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
48
At 60 DAP, the same trend was exhibited from all the genotypes (Fig. 6).
The dry matter partitioned into the different organs varied among the genotypes.
Dry matter accumulation into the different organs of the potato plants may be
attributed to the genetic characteristics of the genotypes. According to Devlin and
Witham (1983), the leaves nearest the root translocated metabolites primarily to
the roots. Photosynthate moving out of the leaves maybe translocated in the
direction of the roots. This may be one possible reason why dry matter content of
the roots and stolons were high in some genotypes.
30
25
13.1.1
20
96-06
573275
15
5.19.2.2
676089
10
Ganza
Dry matter content
Granola
5
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 5. Dry matter content at 45 DAP of seven potato genotypes grown
at La Trinidad under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
49
30
25
13.1.1
20
96-06
573275
15
5.19.2.2
676089
10
Ganza
Dry matter content
5
Granola
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 6. Dry matter content at 60 DAP of seven potato genotypes grown
at La Trinidad under organic production.
At 75 DAP, the dry matter partitioned into the tubers had increased in all
the genotypes. The dry matter partitioned into the leaves, roots and stolons had
decreased diverting assimilates into the tubers (Figure 7).
The roots and stolons had the highest dry matter partitioned in genotype
5.19.2.2. The highest dry matter partitioned into the tubers was in genotypes
5.19.2.2, 96-06 and 13.1.1. The lowest dry matter was partitioned in the stems in
genotypes 96-06 and 13.1.1 followed by 5.19.2.2, cv. Ganza, 573275 and 676089.
The dry matter partitioned into the roots and stolons in genotypes 13.1.1, 96-06
and 676089 had decreased and the dry matter partitioned into the leaves increased
in genotypes 13.1.1, 96-06 and 5.19.2.2 (Figure 7).
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
50
At 90 DAP the dry matter partitioned in the leaves, roots and stolons
increased while dry matter partitioned in the tubers decreased except in genotypes
5.19.2.2 and 96-06. The dry matter partitioned in the stems was lowest in
genotype 573275 followed by 5.19.2.2, 96-06 and cv. Ganza (Figure 7). Results
showed that 5.19.2.2 and 96-06 were of the early maturing genotypes. The stems
were observed to have the lowest dry matter content from 45 to 90 DAP. The
low dry matter in the stem may be due to the fact that the stems are not the storage
organs but merely serve as vehicle for the translocation of assimilates within the
plant.
30
a
a
a
25
a a
a a
13.1.1
ab ab
20
96-06
b
b
a a
a
a
573275
ab ab
a a
a
a
b
15
a
5.19.2.2
a a
676089
10
Ganza
0
Dry matter content
Granola
5
c
b
b
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 7. Dry matter content at 75 DAP of seven potato genotypes grown at La
Trinidad under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
51
40
35
13.1.1
30
96-06
25
573275
20
5.19.2.2
15
676089
Ganza
Dry matter content 10
Granola
5
0
leaves
Stems
Roots and
Tubers
Stolons
Plant organ
Figure 8. Dry matter content at 90 DAP of seven potato genotypes grown
at La Trinidad under organic production.
Dry Matter Accumulation in the Different Plant Organs
Dry matter content of leaves at 45, 60, 75 and 90 DAP is presented in
Figure 9. The dry matter partitioned in the leaves was high at 60 to 75 DAP in
genotype 13.1.1 followed by genotypes 96-06 and 5.19.2.2. Dry matter partitioned
in the leaves at 90 DAP decreased in genotypes 13.1.1 but increased in genotypes
96-06 and 5.19.2.2. Results indicate that most assimilates in the leaves were
translocated to the tubers in genotype 13.1.1 while a three fourth fraction of
assimilates may be translocated to the tubers in genotypes 96-06 and 5.19.2.2.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
52
30
a
a
a
25
a a
13.1.1
ab ab
a
20
a
96-06
abab
573275
15
5.19.2.2
b
676089
10
Ganza
Dry matter content
Granola
5
0
c
b
45
60
75
90
Date after planting
Figure 9. Dry matter content of leaves of seven potato genotypes grown
at La Trinidad under organic production.
The dry matter content of stems among the genotypes evaluated at 45, 60,
75 and 90 DAP is presented in Figure 10. Dry matter partitioned in the stems was
high at 45 DAP in genotypes 96-06 and 13.1.1. Increased dry matter assimilates
in the stem at 60 DAP was shown in cultivar Granola. At 75 DAP genotype
676089 had the highest dry matter assimilates in the stems and continuously
increased at 90 DAP. The dry matter partitioned in the stems of all the genotypes
differed at 45, 60, 75 and 90 DAP. Some genotypes decreased in dry matter
accumulation in the stems at 60 DAP, increased at 75 DAP but decreased at 90
DAP. The fluctuation on dry matter accumulation in the stems may have been
affected by the genetic characteristics of the different genotypes, tested.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
53
35
30
13.1.1
25
96-06
20
573275
a
5.19.2.2
15
a
676089
a
a
Ganza
10
Granola
Dry Matter Content of Stem
5
0
b
45
60
75
90
Days after planting
Figure 10. Dry matter content of stems at 45, 60, 75 and 90 DAP
of seven potato genotypes grown at La Trinidad under organic
production.
Figure 11 shows the dry matter content of roots and stolons at 45, 60, 75
and 90 DAP. The highest dry matter assimilates partitioned in the roots and
stolons were noted at 45 and 75 DAP in genotype 5.19.2.2. . At 90 DAP, dry
matter assimilates partitioned in the roots and stolons increased in most of the
genotypes while this decreased in genotype 5.19.2.2. Results showed that roots
and stolons attained higher dry matter accumulation from 45, 75 and 90 DAP.
According to Devlin and Witham (1983), the leaves nearest the root translocated
metabolites primarily to the roots. Photosynthates moving out of the leaves
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
54
maybe translocated in the direction of the roots. This may be a possible reason
why dry matter content in the roots and stolons were high at 45, 75 and 90 DAP.
40
35
13.1.1
30
a
96-06
25
573275
20
5.19.2.2
a
a
Stolons 15
a
a
676089
Ganza
10
Granola
5
Dry Matter Content of Roots and
0
b
45
60
75
90
Days after planting
Figure 11. Dry matter content of roots and stolons of seven potato genotypes
grown at La Trinidad under organic production.
Dry matter content of tubers at 45, 60, 75 and 90 DAP is presented in
Figure 12. All the genotypes and cultivars tested were observed to have an
increased dry matter content at 60 to 75 DAP. Results showed that dry matter
partitioned into the tubers was high at 45 DAP in genotypes 5.19.2.2 and 13.1.1
while this very low in genotypes 573275 and 676089. Dry matter partitioned in
the tubers increased at 60 to 75 DAP in genotypes 5.19.2.2, 13.1.1 and 96-06.
The high dry matter at 75 DAP indicates early maturity of the genotypes. An
increasing dry matter in genotypes 96-06 and 5.19.2.2 was observed at 90 DAP.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
55
This indicates that maturity in genotypes 96-06 and 5.19.2.2 was at 90 DAP.
Genotype 13.1.1 showed a decrease in dry matter at 75 DAP. The decrease may
indicate maturity of the genotype at 75 DAP.
35
30
13.1.1
a
25
96-06
a
a a
a
20
573275
b
b
5.19.2.2
15
676089
10
Ganza
Granola
5
Dry Matter Content (%) of Tubers
0
45
60
75
90
Days after planting
Figure 12. Dry matter content of tubers of seven potato genotypes grown at La
Trinidad under organic production.
Harvest Index at 45, 60, 75, and 90 DAP
Harvest index of the seven genotypes and cultivars at 45, 60, 75 and 90
DAP is presented in Figure 13. No significant differences among genotypes and
cultivars evaluated were observed at 45 and 60 DAP.
Harvest index differed significantly among the genotypes evaluated at 75
and 90 DAP (Figure 13). At 45 DAP cultivar Granola had the highest harvest
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
56
index followed by cultivar Ganza. The harvest index of cultivar Granola
decreased at 60 DAP while cultivar Ganza had increased harvest index. At 75
DAP genotypes 96-06, 5.19.2.2, cv.Ganza, 676089 and 13.1.1 increased in their
harvest indices. At 90 DAP all the harvest indices of the genotypes and cultivars
decreased except for genotype 96-06 which had an increased harvest index.
Results showed that the harvest indices in most of the genotypes increased which
conforms with the earlier result of an increase in dry matter content in tubers at 75
DAP in all the genotypes. This implies that increase in economic yield may result
on the increase in harvest index. At 90 DAP a decrease in the harvest index was
observed hence dry matter content of tubers at 90 DAP decreased while the dry
matter in the leaves, stolons and tubers increased. Results showed that a decrease
in economic yield would mean low harvest index.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
57
0.6
a
a
0.5
a
13.1.1
a
a a
96-06
0.4
a
573275
b b
0.3
5.19.2.2
bc
bc
676089
0.2
Harvest Index
Ganza
cd
0.1
Granola
0
b
d
45
60
75
90
Days after planting
Figure 13. Harvest index of seven potato genotypes grown at La Trinidad under
organic production.
Leaf Miner Incidence at 45, 60, and 75 DAP
Visual rating for leaf miner incidence was done at the potato vegetative
stage. Observation showed that most of the genotypes were highly resistant at 45
DAP except for cultivar Granola (Figure 14). At 60 DAP most of the genotypes
had intermediate resistant ratings except for genotype 573275 which is highly
resistant. The infestation by leaf miner at 75 DAP slightly increased in genotypes
13.1.1, 96-06, 5.19.2.2, and 676089 while this increased rapidly in cv. Granola.
Based on the results the genotypes evaluated and cultivar Ganza were moderately
resistant to leaf miner while cultivar Granola showed susceptibility to leaf miner
in conformity with the results of Simongo, et al. (2004). The moderate infection
by leaf miner to the genotypes tested showed their resistance to the pest attributed
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
58
to the crop production diversity practiced in the study area and the set-up of
yellow traps.
6
5
13.1.1
4
96-06
573275
3
5.19.2.2
676089
Leaf miner 2
Ganza
Granola
1
0
45
60
75
Days After Planting
Figure 14. Leaf miner ratings of seven potato genotypes grown at La
Trinidad under organic production.
Late Blight Infection at 60 and 75 DAP
Late
blight
infection
at 65 and 75 is presented in Figure 15. Results
showed that the prevailing weather during the evaluation period did not favor the
occurrence of the disease. At 60 to 75 DAP genotypes 5.19.2.2, 573275, 96-06
and 13.1.1 showed zero infections (Figure 15). The genotype 13.1.1 and cultivar
Ganza showed the least infection at 60 and 75 DAP while infection from cultivar
Granola increased at 75 DAP. Results indicate, infection was moderate as
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
59
exhibited by the susceptible cultivar Granola. The low late blight incidence may
be attributed to the low relative humidity that was recorded during the conduct of
the study associated with their genetic characteristics. Horton (1987) reported
that the average relative humidity required for potato production is 86%
confirming that the relative humidity within the evaluation period of the study
did not favor the development of the disease. However, some of the genotypes
tested showed resistance to late blight.
4.5
4
3.5
13.1.1
3
96-06
573275
2.5
5.19.2.2
2
676089
1.5
Ganza
Late Blight Rating
1
Granola
0.5
0
60
75
Days after planting
Figure 15. Late blight rating of seven potato genotypes grown at La Trinidad
under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
60
Correlation Analysis
Correlation Between Meteorological Data and Plant Vigor of the Seven Potato
Genotypes
No significant correlation of plant vigor with minimum temperature,
maximum temperature, relative humidity, rainfall and sunshine duration in all the
genotypes evaluated was noted (Table 8).
In the case of light intensity, significant positive correlation was found on
the plant vigor rating of 96-06, 573275 and cultivar Ganza. This result reveals
that these three genotypes exhibited highly vigorous growth as light intensity
increased. This implies that genotype 96-06, 573275 and cultivar Ganza are
suitable for dry season planting. This finding contradicts the report of Gardner et
al., (1985) that if the light level continues to increase, there is less increase in
carbon exchange rate (CER) for each unit increase in light level until the light
saturation level is reached.
As shown by this results, any increase in light level after this level will not
significantly increase CER; therefore leaves are more efficient at utilizing light
energy at low irradiance levels.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
61
Table 8. Correlation between meteorological data and plant vigor of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza
Granola
Min. Temperature
-
-0.649
-0.649
-
-0.983
-0.649
0.983
Max. Temperature
-
-0.693
-0.693
-
-0.971 -0.6933
0.971
Relative Humidity
-
-0.991
-0.991
-
-0.381
-0.991
0.381
Rainfall
-
0.447
0.470
-
-0.530
0.470
0.530
Sunshine Duration
-
0.872
0.872
-
0.860
0.872
-0.860
Light Intensity
-
0.996*
0.996*
-
0.572
0.996*
0.572
* = significant at 5% level of significance
Correlation Between Meteorological Data and Canopy Cover of the Seven Potato
Genotypes
Canopy cover of the genotypes and cultivars showed no significant
correlation with minimum temperature, RH, rainfall and light intensity.
Maximum temperature had a significant negative correlation (R = -0.949) with
canopy cover while sunshine duration showed a positive significant correlation
(R = 0.983) with canopy cover in genotype 96-06 (Table 9). As results indicate, as
the temperature increases, canopy development decreases confirming the report of
Periera and Shock (2006), that potato is best adapted to cool climates such as
tropical highlands with mean daily temperatures favoring foliar development and
retard in tuberization. Based on the result canopy cover increases as sunshine
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
62
duration increases. This finding corroborates with the report of Anon, (2007)
that long bright days favor photosynthesis and development of top growth. As
this result showed, genotype 96-06 was responsive to increased sunshine duration.
Although correlation was not significant in most of the genotypes,
negative correlation between temperature and canopy was noted. The increase in
temperature may enhance a decrease in canopy cover. Ewing (1981) pointed out
that at high temperature, changes in plant morphology and a significant reduction
in tuber yield. Solar radiation is positively correlated with canopy cover in all the
genotypes tested. The increase in solar radiation may contribute for the
development of greater canopy cover and the long bright days may enhance
development of top growth.
Table 9. Correlation between meteorological data and canopy cover of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275
5.19.2.2
676089
Ganza
Granola
Min. Temperature -0.868 -0.659
-0.970
-0.916
-0.886
-0.960
-0.104
Max. Temperature -0.895 -0.949*
-0.751
-0.910
-0.802
-0.791
-0.764
Relative Humidity -0.221
0.065
-0.450
-0.182
-0.390
-0.400
0.576
Rainfall
0.064
0.264
-0.143
-0.088
0.085
-0.115
0.477
Sunshine Duration 0.874
0.983*
0.677
0.852
0.783
0.724
0.871
Light Intensity
0.294
-0.012
0.534
0.269
0.455
0.483
-0.566
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
63
Correlation Between Meteorological Data and Leaf Area Index of the Seven
Potato Genotypes
Genotype 96-06 (Table 10) showed significant negative correlation
between minimum temperature and leaf area index that as minimum temperature
increases leaf area indices decreased. No significant correlation was shown
among the leaf area indices of the other genotypes with any of the meteorological
data. This implies that the leaf indices of the other genotypes were not affected
by temperature, relative humidity, rainfall, sunshine duration and light intensity.
The result further implies that leaf area index is attributed to the inherent
characteristics of the genotypes.
Table 10. Correlation between meteorological data and leaf area index
of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089
Ganza Granola
Min. Temperature
-0.817 -0.999*
-0.272
-0.631
-0.471
-0.321
-0.280
Max. Temperature -0.983 -0.727
0.496
0.113
0.299
0.451
-0.882
Relative Humidity
0.773
0.302
-0.854
-0.581
-0.725
-0.827
0.792
Rainfall
-0.292
-0.766
-0.805
-0.974
-0.913
-0.835
0.367
Sunshine Duration
0.904
0.526
-0.702
-0.364
-0.534
-0.665
0.973
Light Intensity
-0.615
-0.087
0.748
0.744
0.857
0.930
-0.972
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
64
Correlation Between Meteorological Data and Net Assimilation Rate of the
Seven Potato Genotypes
Except for rainfall with genotype 5.19.2.2, no significant correlation was
shown between meteorological data and net assimilation rate of the genotypes
(Table 11). Rainfall has significant negative correlation with the net assimilation
rate of genotype 5.19.2.2. This indicates that as rainfall increases, the net
assimilation rate of genotype 5.19.2.2 decreases. This implies that 5.19.2.2 is
not suitable for planting during the wet season but rather during the dry season.
During rainy months is genotype produces higher haulm growth with less yield.
Table 11. Correlation between meteorological data and net assimilation rate
of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06 573275
5.19.2.2
676089
Ganza
Granola
Min. Temperature
-0.442 -0.309
-0.280
-0.784
-0.562
-0.789
0.478
Max. Temperature
0.331
0.462
0.489
-0.105
0.196
-0.991
-0.293
Relative Humidity -0.747 -0.834 -0.851
-0.390
-0.647
0.802
0.720
Rainfall
-0.899 -0.828
-0.810
-0.999*
-0.951
-0.247
0.916
Sunshine Duration -0.562 -0.674 -0.697
-0.153
-0.441
0.923
0.529
Light Intensity
0.874
0.735
0.745
0.581
0.798
-0.551
0.854
** = Highly significant at 1% level of significance
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
65
Correlation Between Meteorological Data and Crop Growth Rate of the Seven
Potato Genotypes
Correlation between meteorological data and crop growth rate is presented
in Table 12. Significant negative correlation between rainfall and crop growth
rate was noted in genotypes 13.1.1 and 5.19.2.2. It was observed that, as rainfall
increase the crop growth rates of genotypes 13.1.1 and 5.19.2.2 decreases. This
implies that genotypes 13.1.1 and 5.19.2.2 are best adapted under dry season
cropping. The crop growth rates of the other genotypes and cultivars were not
affected by any of the meteorological data.
Table 12. Correlation between meteorological data and crop growth rate of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICENT
DATA
13.1.1
96-06 573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.799
-0.895
-0.031
-0.831
-0.049
-0.550
0.693
Max. Temperature
-0.130
-0.307
0.692
-0.183
0.679
0.212
-0.029
Relative Humidity
-0.367
-0.193
-0.955
-0.316
-0.949
-0.659
0.510
Rainfall
-0.999**
-0.981
-0.638
-0.998*
-0.651
-0.946
0.790
Sunshine Duration
-0.128
0.052
-0.854
-0.075
-0.845
-0.455
0.284
Light Intensity
0.561
0.403
0.797
0.516
0.795
0.807
-0.686
* = Significant at 5% level of significance
** = Highly significant at 1% level of significance
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
66
Correlation Between Meteorological Data and Dry Matter Content of Leaves of
the Seven Potato Genotypes
There is significant effect of the environmental factors on dry matter
contents of the leaves of genotypes 13.1.1, 573275 and cultivar Granola (Table
13). Significant positive correlation was exhibited between 13.1.1 and rainfall.
Significant negative correlation (R = 0.979) between dry matter content of leaves
and minimum temperature was shown in genotype 573275. This indicates that dry
matter content of the leaves decreases as temperature increases. Significant
positive correlation was also observed between sunshine duration and dry matter
content of the leaves of cultivar Granola. Hence, as sunshine duration increases
dry matter content of the leaves increases. This implies that cultivar Granola is
best grown under long bright days.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
67
Table 13. Correlation between meteorological data and dry matter content of
leaves of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.436
-0.754 -0.979*
-0.669
-0.922
-0.777
-0.314
Max. Temperature -0.009
0.051
0.098
-0.087
-0.150
-0.429
-0.768
Relative Humidity -0.425 -0.366
-0.023
-0.270
0.040
0.283
0.864
Rainfall
-0.947*
-0.824
-0.171
-0.899
-0.537
-0.602
-0.059
Sunshine Duration -0.259 -0.135
0.217
-0.050
0.297
0.518
0.962*
Light Intensity
0.700
0.432
-0.334
0.443
-0.133
-0.213
-0.773
* = Significant at 5% level of significance
Correlation Between Meteorological Data and Dry Matter Content of Stems of the
Seven Potato Genotypes
Correlation between meteorological data and dry matter content of stems
is presented in Table 14. Significant positive correlation between rainfall and dry
matter content of the stems was exhibited by genotype 96-06. This indicates that
the dry matter content of the stems in genotype 96-06 increases as rainfall
increases. Thus, this implies that genotype 96-06 is best adapted under wet season
cropping..
Genotype 573275 showed significant positive correlations between
maximum temperature and dry matter content of the stems. As results show dry
matter content of the stems of genotype 573275 increased as temperature
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
68
increased. Negative significant correlation (R = -0.976) between sunshine
duration and dry matter content in the stems was also shown by genotype 573275.
Correlation between dry matter content of stems and sunshine duration showed
that dry matter content of stems increases as sunshine duration decreases. This
implies that genotype 573275 is best adapted under short bright days.
Table 14. Correlation between meteorological data and dry matter content of
stems of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICEINT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.200
0.797
0.728
0.221
-0.435
-0.400
-0.599
Max. Temperature -0.487
0.318
0.984*
0.125
-0.282
0.135
-0.716
Relative Humidity
0.563
0.125
0.912
-0.020
0.092
-0.497
0.612
Rainfall
0.142
0.943*
0.191
0.225
-0.409
-0.757
-0.247
Sunshine Duration
0.539
-0.104
-0.976*
-0.076
0.194
-0.321
0.684
Light Intensity
-0.554
-0.342
0.796
-0.035
0.013
0.642
-0.506
* = Significant at 5% level of significance
Correlation Between Meteorological Data and Dry Matter Content of Roots and
Stolons of the Seven Potato Genotypes.
The correlations between metrological data and dry matter content of roots
and stolons are presented in Table 15. No significant correlation was shown
among meteorological data and dry matter content of roots and stolons in all the
genotypes and cultivars evaluated. This may imply that dry matter content of the
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
69
roots and stolons was not much affected by the temperature, relative humidity,
rainfall, sunshine duration and light intensity. As the result implies dry matter
contents of roots and stolons may be affected by the inherent characteristics of
the genotypes.
Table 15. Correlation among meteorological data and dry matter content of roots
and stolons of the seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
0.195
0.331
0.105
0.858
0.113
-0.360
-0.531
Max. Temperature -0.444 -0.299
-0.106
0.708
-0.518
-0.341
-0.702
Relative Humidity
0.802
0.689
0.235
-0.407
0.850
0.236
0.641
Rainfall
0.735
0.808
0.267
0.661
0.677
-0.234
-0.155
Sunshine Duration
0.637
0.504
0.174
-0.577
0.700
0.298
0.692
Light Intensity
-0.917
-0.830
-0.281
0.217
-0.948
-0.162
-0.555
Correlation Between Meteorological Data and Dry Matter Content of Tubers of
the Seven Potato Genotypes.
Table 16 shows the correlation between meteorological data and dry
matter content of tubers. No significant correlation was observed between the
meteorological data and dry matter content of tubers in all the genotypes and
cultivars evaluated. Tuber dry matter content of all the genotypes, as the results
show was not affected by temperature, relative humidity, rainfall, sunshine
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
70
duration and light intensity. This indicates that dry matter content of tubers is
attributed to their genetic characteristics and not affected by environmental
factors. As Peet (2006) reported, dry matter content varies between varieties and
is a strongly inherited characteristic.
Table 16. Correlation between meteorological data and dry matter content of
tubers of seven genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
-0.223
-0.677
-0.767
0.105
-0.351
-0.566
-0.513
Max. Temperature
0.391
-0.292
-0.308
0.562
0.257
0.034
0.045
Relative Humidity -0.743 -0.073
-0.117
-0.752
-0.641
-0.472
-0.449
Rainfall
-0.726
-0.779
-0.906
-0.377
-0.798
-0.919
-0.849
Sunshine Duration -0.580
0.117
0.103
-0.674
-0.458
-0.256
-0.250
Light Intensity
0.862
0.255
0.326
0.785
0.784
0.658
0.619
Correlation Between Meteorological Data and Harvest Index of the Seven Potato
Genotypes
The correlation between meteorological data and harvest index of all the
genotypes and cultivars evaluated shown in Table 17. No significant correlation
between meteorological data and harvest index was noted. As the result implies,
the harvest indices of all the genotypes and cultivars evaluated were not affected
by the temperature, rainfall, relative humidity, sunshine duration and light
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
71
intensity. This therefore implies that harvest index was solely attributed to the
genetic characteristics of the genotypes and cultivars studied.
Table 17. Correlation between meteorological data and harvest index of the
seven potato genotypes.
METEOROLOGICAL
CORRELATION COEFFICIENT
DATA
13.1.1
96-06
573275 5.19.2.2 676089 Ganza Granola
Min. Temperature
0.212
-0.729
-0.737
0.058
0.035
0.276
0.078
Max. Temperature
0.597
-0.228
-0.249
0.615
0.375
0.546
-0.413
Relative Humidity -0.724 -0.207
-0.181
-0.866
-0.527
-0.600
0.669
Rainfall
-0.244
-0.923
-0.915
-0.503
-0.306
-0.093
0.521
Sunshine Duration -0.678
0.015
0.040
-0.759
-0.462
-0.589
0.554
Light Intensity
0.728
0.412
0.389
0.821
0.561
0.577
-0.743
Correlation Among Characters
Meyer and Anderson (1952) reported that the development of every organ
in growing plant is attributed to some degree by physiological processes of
physico- chemical conditions prevailing in some other organ or organs. Such
relationship existing among the organs of a plant are termed growth correlations
or simply correlations. Growth correlations are not only exerted by one organ on
another but also occur among tissues and even among cells.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
72
Table 18 shows the summary of the correlation coefficient of seven potato
genotypes characters studied. Canopy cover showed no significant correlation
with the other plant characters except on the harvest index.
Canopy cover showed significant positive correlation (R = 0.665) with
harvest index. Thus, as canopy cover increases harvest index increases which
contradicts the statement of Belanger, et al., ( 2000), that any factor resulting in a
decrease in total biomass will indirectly decrease the harvest index . No
significant correlation was observed in leaf area index with other plant characters.
This result indicates that leaf area index was not affected by plant character.
Significant positive correlation between net assimilation rate and crop
growth rate was noted. It was noted that net assimilation rate increased as the
crop growth rate increased which is conclusive since crop growth rate is the
product of net assimilation rate when multiplied with leaf area index as cited by
Gardner et al. (1985).
Significant positive correlation (R = 0.652) between net assimilation rate
and extra large tuber weight was observed. This indicates that extra large tuber
weight increase as net assimilation rate increases.
Correlation in crop growth rate with other characters was not significant.
This implies that crop growth rate was not affected by other plant characters.
For the yield components, no significant correlations were noted, thus,
none of the plant characters studied affected the yield.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
73
Dry matter content of leaves, stems, roots and stolons and tubers showed
no significant correlation among all the characters studied.
No significant correlation between harvest index and among other plant
characters, which implies that harvest index, was not affected by any of the
characters. As results showed, dry matter content of leaves, stems, roots, stolons
and tubers were not affected by any other plant character.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
74
Table 18. Correlation among growth and yield parameters of the seven genotypes evaluated
CC
LAI
NAR
CGR
XLWT.
LWT.
MWT.
SWT.
MAR WT.
NMWT
TOT.YLD.
LDMC
SDMC
RSDMC
TDMC
HI
CC
1.000
-0.379
-0.126
-0.279
0.127
-0.191
0.055
0.189
0.261
0.121
0.314
0.030
-0.186
-0.246
0.407
0.665*
LAI
1.000
0.323
0.548
0.201
-0.463
-0.283
-0.291
0.040
-0.419
-0.286
0.085
-0.371
-0.092
-0.064
0.197
NAR
1.000
0.840**
0.652*
0.033
-0.155
-0.159
-0.079
-0.525
0.062
0.061
-0.087
0.535
-0.076
-0.508
CGR
1.000
0.322
0.696*
0.418
-0.224
-0.099
-0.529
-0.050
0.080
-0.240
0.463
-0.008
-0.367
XLWT
1.000
-0.445
0.226
0.106
0.414
-0.017
0.390
0.056
0.285
0.224
-0.361
-0.019
LWT.
1.000
-0.061
-0.119
-0.742
-0.293
-0.147
-0.283
0.108
0.193
0.253
-0.259
MWT.
1.000
0.007
0.194
0.476
0.714
-0.282
0.072
-0.236
-0.011
-0.098
SWT.
1.000
0.038
0.169
0.578
-0.072
-0.180
-0.411
-0.260
0.039
MRWT.
1.000
0.279
0.408
0.117
0.047
-0.199
-0.144
0.083
NMWT.
1.000
0.234
0.098
0.198
-0.121
-0.162
-0.095
Tot. yld.
1.000
-0.255
-0.183
-0.330
-0.101
-0.097
LDMC
1.000
0.329
0.405
-0.080
-0.148
SDMC
1.000
0.542
-0.271
-0.257
RSDMC
1.000
0.217
-0.379
TDMC
1.000
0.433
HI
1.000
** = Highly significant at 5% level of significance
XLWT = extra large tuber weight
TOT YLD = total yield
* = Significant at 5% level of significance LWT = large tuber weight LDMC = leaves dry matter content
CC = canopy cover
MWT = medium tuber weight
SDMC = stem dry matter content
LAI = leaf area index
SWT -= small tuber weight
RSDMC = root & stolons dry matter content
NAR = net assimilation rate
MRWT = marble tuber we
TDMC = tuber dry matter content
CGR = crop growth rate
NMWT = non-marketable tuber weight
HI = harvest index
Growth, yield and dry matter partitioning of potato genotypes under organic production at La Trinidad, Benguet / Donita K. Simongo. 2007
75
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted to determine assimilates partitioning in the
leaves, stems, roots, stolons and tubers during the different stages of the potato
plant development; compare the efficiency of potato genotypes in terms of dry
matter partitioning under organic production, and determine the best time of
harvesting for optimum dry matter accumulation.
Seven potato genotypes and cultivars grown and selected from previous
studies under organic production were evaluated from November 2006 to
February 2007 at La Trinidad, Benguet under organic production. Treatments
were laid out following the Randomized Complete Block Design with 40 tubers
per replication. Destructive sampling was done at 45 DAP and every 15 days
thereafter until harvest. The data gathered were: meteorological data, soil
analysis, growth parameters, yield components, dry matter parameters and other
data. The data was analyzed through ANOVA using the single factorial in RCBD
except for leaf miner and late blight ratings. Correlation between meteorological
data and growth characters and in among plant characters were analyzed using
Pearson correlation movement correlation coefficient (R), which characterizes the
independence of X and Y.
The minimum and maximum air temperature during the study period
ranged from 12.6 to 15.6 oC and 23.5 to 24.2 oC, respectively while relative
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
76
humidity ranged from 77 to 80 %. A very low rainfall about 2.5, 2.4 and 0.05 mm
was noted in November, December and January. Sunshine duration ranged from
381.4 to 521.6 mm. Light intensity ranged from 45.1 to 76.4 Klux. Soil pH is
6.72 before and 6.31 after harvest. Organic matter, phosphorus, potassium and
nitrogen in the soil increased.
Genotype 13.1.1 significantly had high plant survival of 98 % followed by
genotypes 5.19.2.2 and 13.1.1 with plant survival of 97 and 85%, respectively.
Genotypes 13.1.1 and 5.19.2.2 significantly had highly vigorous growth at 30, 45
and 60 DAP. Cultivar Granola had moderate vigor at 30 and 45 DAP and less
vigor at 60 DAP.
Canopy cover was significantly high in genotype 96-06 followed by
5.19.2.2 and 13.1.1. On leaf area index genotype 5.19.2.2 had the highest leaf
area index at 45 DAP followed by genotypes 96-06 and 13.1.1. Genotype
5.19.2.2 had the highest leaf area index at 45 DAP followed by genotypes 96-06
and 13.1.1 while 573275 and cultivar Granola had the lowest leaf area index. At
60 DAP, all the genotypes increased in their leaf area indices with genotype
5.19.2.2 having the highest followed by 96-06 and 676089. Genotypes 5.19.2.2,
96-06, 13.1.1 and cultivar Ganza showed an increasing leaf area indices at 75
DAP while genotypes 676089, 573275 and cultivar Granola decreased.
No significant differences were observed among genotypes on their net
assimilation rates at 45 and 75 DAP. At 60 DAP genotype 5.19.2.2 significantly
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
77
had the highest net assimilation rate. On the crop growth rate, genotype 5.19.2.2
had the highest at 45 to 65 DAP followed by 676089 at 45 DAP and 96-06 at 60
DAP followed by 676089. Genotype 676089 increased in crop growth rate
attaining the highest among the genotypes at 75 DAP. Genotype 573275 and
cultivar Ganza increased at 75 DAP but not significantly comparable with
676089.
Genotypes 5.19.2.2, 13.1.1 and 96-06 had the highest total yield of 4.57,
4.21 and 4.13 kg, respectively and computed marketable yields with respective
means of 6.33, 5.46 and 5.92 tons/ha. Genotype 13.1.1 had produced the most
marketable tubers and the highest weight of tubers. Genotype 5.19.2.2 produced
the heaviest weights of large, medium, small and marble tubers.
On the partitioning of assimilates in different plant organs of the seven
potato genotypes and cultivars, the highest assimilate was partitioned into the
roots and stolons of genotype 5.19.2.2 at 45, 60 and 75DAP and in cultivar Ganza
at 90 DAP. The least assimilate was partitioned into the stems in genotypes
573275, 676089 and 96-06 at 45 to 60 DAP; in genotypes 13.1.1 and 96-06 at
75DAP and in genotype 573275 at 90 DAP.
As to assimilate partitioning in the leaves, highest dry matter content in
the leaves in genotype 13.1.1 was noted at 75 DAP. The dry matter content in the
stems was high at 90 DAP in genotype 676089. In the roots and stolons, the
highest assimilates was partitioned at 90 DAP in cultivar Ganza. The highest
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
78
assimilates partitioned in tubers was noted at 90 DAP in genotypes 96-06 and
5.19.2.2 but at 75 DAP high assimilate was partitioned in all the genotypes.
Harvest index differed significantly among the genotypes evaluated at 75
and 90 DAP but did not differ at 45 and 60 DAP. Cultivar Granola had the
highest harvest index at 45 DAP but decreased at 60 DAP with cultivar Ganza
having the highest harvest index followed by genotypes 96-06 and 573275. At 75
DAP, genotypes 96-06, 5.19.2.2, cultivar Ganza, 676089 and 13.1.1 increased in
their harvest indices while 573275 decreased. At 90 DAP, all the harvest indices
of the genotypes decreased except for genotype 96-06 which had an increased in
harvest index.
Data on leaf miner and late blight incidence was recorded during the
conduct of the study. Genotypes 5.19.2.2, 573275, 96-06 and 13.1.1 had zero late
blight infection at 60 to 75 DAP. The genotype 13.1.1 and cultivar Ganza showed
the least infection but was moderately infected at 75 DAP. At 60 DAP most of
the genotypes were of intermediate resistance except for genotype 573275 which
is highly resistant. The infestation of leaf miner at 75 DAP slightly increased from
genotypes 13.1.1, 96-06, 5.19.2.2, and 676089 while this increased rapidly with
cultivar Granola. Infection of late blight was moderate as showed by the
susceptible check cultivar Granola with late blight rating of 4 with only 25%
infection at 75 DAP while the rest showed minimal infection with ratings of 2
(2.5%) to zero infection at 75 DAP.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
79
Correlation analysis revealed significant positive correlations in: plant
vigor with light intensity in genotypes 96-06, 573275, and cultivar Ganza; dry
matter content of leaves with sunshine duration in cultivar Granola; dry matter
content of stems with rainfall in genotype 96-06 and with maximum temperature
in genotype 573275. Significant negative correlations was observed in: canopy
cover with maximum temperature in genotype 96-06; crop growth rate with
rainfall in genotypes 13.1.1 and 5.19.2.2; leaf area index with minimum
temperature. No significant correlation was observed in temperature, relative
humidity, rainfall, sunshine duration and light intensity with dry matter content of
roots, stolons, tubers and harvest indices in all the genotypes and cultivars tested.
On the correlation among plant characters, canopy cover is positively
correlated significantly with harvest index, net assimilation rate and extra large
tubers and between net assimilation rate and crop growth rate.
Conclusions
Based on the results of the study the following conclusions are drawn:
1) Among the genotypes and cultivars evaluated 96-06, 13.1.1 and 5.19.2.2 were
best performers based on survival, vigor, canopy cover, leaf area index, net
assimilation rate and crop growth rate.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
80
2) Genotypes 5.19.2.2, 96-06 and 13.1.1 had the highest total yield per plot and
computed marketable yield indicating that these genotypes may be the most
adapted under organic production at La Trinidad.
3) On the dry matter partitioning of assimilates, the roots and stolons had the
highest assimilates partitioned in genotype 5.19.2.2 at 45, 60 and 75 DAP.
4) Assimilates were partitioned in the tubers at 75 DAP in most of the
genotypes except for 96-06 and 5.19.2.2 which had partitioned assimilates in
the tubers at 90 DAP.
5) Dry matter content of roots, stolons, tubers and harvest index were not
affected by temperature, rainfall, sunshine duration and light intensity in any
of the genotypes. This shows that dry matter content is attributed to the
inherent characteristics of the genotypes, tested.
6) The significant positive correlation of dry matter content of some organs
with sunshine duration indicates the importance of longer expressure of the
genotypes to bright sunshine.
7) The negative correlation of crop growth rate with rainfall in 13.1.1 and
5.19.2.2 shows the suitability of these genotypes to dry season planting.
8) Among the genotypes evaluated 573275 was highly resistant to leaf miner,
cultivar Ganza was intermediate and 13.1.1, 5.19.2.2, 676089 and 96-06
were moderately resistant. Genotypes 5.19.2.2, 573275, 96-06 and 13.1.1
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
81
were resistant to late blight. The resistance of these genotypes to leaf miner
and late blight indicates their adaptability to organic production.
Recommendations
Based on the results of the study, the following are recommended:
1. Genotypes 96-06, 13.1.1 and 5.19.2.2 may be planted for organic production
at La Trinidad, Benguet.
2. Genotypes 13.1.1, 573275, 676089, cultivars Ganza and Granola may be
harvested as early as 75 DAP. Genotypes 96-06 and 5.19.2.2 could be
harvested at 90 DAP.
3. Since sunshine duration significantly affects dry matter content of leaves
cultural management practices that encourage maximum sunlight interception
should be practiced. These practices may include proper spacing and
cropping scheme.
4. Genotypes 13.1.1 and 5.19.2.2 are best planted during the dry season.
5. Since dry matter content of the tubers was not affected by any of the
environmental factors in the study, verification should be done in other
locations and seasons.
6. The strong indication that dry matter allocation in the tubers is largely genetic
encourages researchers to continuously search for genotypes with efficient dry
matter partitioning, high yield and harvest index under organic production.
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
82
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88
APPENDICES
APPENDIX TABLE 1. Analysis of variance for plant survival
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUT
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
ED F
.05 .01
Replication 2 392.667
196.333
Treatment 6
11110.286 1851.714
11.17**
3.00 4.82
Error 12
1990.000
165.833
Total 20
13492.952
** Highly significant CV% = 17.73
SX = 7.43
APPENDIX TABLE 2. Analysis of variance for plant vigor at 30 dap
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.667
8.333
Treatment 6 14.476
2.413
6.20** 3.00
4.82
Error 12
4.667
0.389
Total 20
19.810
** Highly significant CV% = 16.58
SX = 0.36
APPENDIX TABLE 3. Analysis of variance for plant vigor at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.286
0.143
Treatment 6
10.286
1.714
12.0** 3.0
4.82
Error 12
1.714
0.143
Total 20
** Highly significant CV% = 8.82
SX = 0.22
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
89
APPENDIX TABLE 4. Analysis of variance for plant vigor at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.381
0.190
Treatment 6
21.333
3.556
44.8**
3.0 4.82
Error 12
0.952
0.079
Total 20
22.667
** Highly significant CV% = 6.50
SX = 0.16
APPENDIX TABLE 5. Canopy cover at 30 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2
299.810
149.905
Treatment 6
2078.000
346.333
8.01**
3.0 4.82
Error 12
518.857
43.238
Total 20
2896.667
** Highly significant CV% = 18.76
SX = 3.80
APPENDIX TABLE 6. Analysis of variance for canopy cover at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 590.095
295.048
Treatment 6
3190.286
531.714
10.92**
3.0 4.82
Error 12
584.572
48.714
Total 20
4364.952
** Highly significant CV% = 22.48
SX = 4.03
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
90
APPENDIX TABLE 7. Analysis of variance for canopy cover at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 586.952
293.476
Treatment 6
5134.476
855.746
29.48**
3.0 4.82
Error 12
348.381
29.032
Total
20
6089.810
** Highly significant CV% = 12.76
SX = 3.11
APPENDIX TABLE 8. Analysis of variance for canopy cover at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 60.667
30.333
Treatment 6
3009.619
501.603
24.01** 3.0
4.82
Error 12
250.667
20.889
Total 20
3320.952
** Highly significant CV% = 17.32
SX = 2.64
APPENDIX TABLE 9. Analysis of variance for leaf area index at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.004
0.002
Treatment 6 0.050
0.008
7.06**
3.0 4.82
Error 12
0.014
0.001
Total 20
0.069
** Highly significant CV% = 4.30
SX = 0.02
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
91
APPENDIX TABLE 10. Leaf area index at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 111.870
55.935
Treatment 6
40293.104 6715.517
21.96**
3.0 4.82
Error 12
3669.256
305.771
Total 20
44074.230
** Highly significant CV% = 16.43
SX = 10.10
APPENDIX TABLE 11. Analysis of variance for leaf area index at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 190.062
95.031
Treatment 6
49807.532 8301.255
12.31** 3.0
4.82
Error 12
8091.235
674.270
Total
20
58088.829
** Highly significant CV% = 25.94
SX = 14.99
APPENDIX TABLE 12. Net assimilation rate at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 16.835
8.417
Treatment 6
151.713
25.285
1.67ns
3.0 4.82
Error 12
182.234
15.186
Total 20
350.782
nsnot significant CV% = 20.63
SX = 2.25
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
92
APPENDIX TABLE 13. Analysis of variance for net assimilation rate at 60
DAP (g/cm2/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 8.081
4.041
Treatment 6 0.547
8.425
1.57ns
3.0 4.82
Error 12
64.367
5.364
Total 20
72.995
nsnot significant CV% = 13.23
SX = 1.34
APPENDIX TABLE 14. Analysis of variance for net assimilation rate at
75 DAP (g/cm2/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 1.738
0.869
Treatment 6
84.838
14.140
3.63*
3.0 4.82
Error 12
46.736
3.895
Total 20
133.312
*Significant CV% = 21.95
SX = 1.14
APPENDIX TABLE 15. Analysis of variance for crop growth rate at 45 DAP
(g/cm2soil/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.244
0.122
Treatment 6
4.691
0.782
2.20ns
3.0 4.82
Error 12
4.268
0.356
Total 20
4.268
nsnot significant CV% = 19.63
SX = 0.34
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
93
APPENDIX TABLE 16. Analysis of variance for crop growth rate at 60 DAP
(g/cm2soil/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.079
0.039
Treatment 6
1.734
0.287
1.44ns
3.0 4.82
Error
12 2.387
0.199
Total 20
4.189
nsnot significant CV% = 17.77
SX = 0.26
APPENDIX TABLE 17. Analysis of variance for crop growth rate at 75 DAP
(g/cm2soil/day)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 0.066
0.033
Treatment 6 3.191
0.532
3.72*
3.0
4.82
Error 12
1.922
0.160
Total 20
5.179
*Significant CV% = 26.86
SX = 0.23
APPENDIX TABLE 18 Analysis of variance for number of marketable extra
large tubers per plot.
SOURCE OF DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 69.714
34.857
Treatment 6
182.476
30.413
3.41*
3.0
4.82
Error 12
106.952
8.913
Total 20
359.952
*Significant CV% = 26.32
SX = 1.72
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
94
APPENDIX TABLE 19. Analysis of variance for number of marketable large
tubers per plot
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 249.810
124.905
Treatment 6
1641.905
273.651
5.95**
3.0 4.82
Error 12
551.524
45.960
Total 20
2443.238
** Highly significant CV% = 20.95
SX = 3.91
APPENDIX TABLE 20 Analysis of variance for number of marketable medium
tubers per plot.
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 382.952
191.476
Treatment 6
3032.667
505.444
268ns
3.0 4.82
Error 12
2265.048
188.754
Total 20
5680.667
nsnot significant CV% = 27.28
SX = 7.93
APPENDIX TABLE 21. Analysis of variance for number of marketable small
tubers per plot
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 50.667
25.333
Treatment 6
1334.952
222.492
5.33** 3.0
4.82
Error 12
501.333
41.778
Total 20
1886.952
** Highly significant CV% = 17.07
SX = 3.73
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
95
APPENDIX TABLE 22. Analysis of variance for number of marketable marble
tubers per plot.
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 514.667
257.333
Treatment 6
1162.952
193.825
1.02ns
3.0 4.82
Error 12
2279.333
189.944
Total 20
1906.952
nsnot significant CV% = 25.66
SX = 7.96
APPENDIX TABLE 23. Analysis of variance for number of non-marketable
tubers per plot
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 256.095
128.048
Treatment 6
1761.619
293.603
1.48ns
3.0 4.82
Error 12
2379.238
198.270
Total 20
43.396.952
nsnot significant CV% = 28..45
SX = 8.13
APPENDIX TABLE 24. Analysis of variance for weight of marketable extra
large tubers per plot (kg)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.106
0.053
Treatment 6 1.361
0.227
6.96**
3.0 4.82
Error 12
0.391
0.033
Total 20
1.858
** Highly significant CV% = 8.93
SX = 0.10
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
96
APPENDIX TABLE 25. Analysis of variance for weight of marketable large
tubers per plot (kg)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 1.026
0.513
Treatment 6 3.871
0.645
5.20** 3.0
4.82
Error 12
1.487
0.124
Total 20
6.384
** Highly significant CV% = 12.97
SX = 0.20
APPENDIX TABLE 26. Analysis of variance for weight of marketable
medium tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 1.427
0.713
Treatment 6 5.123
0.854
4.11*
3.0 4.82
Error 12
2.495
0.208
Total 20
9.045
* Significant CV% = 16.56
SX = 0.26
APPENDIX TABLE 27. Analysis of variance for weight of marketable small
tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.830
0.415
Treatment 6 2.211
0.369
2.09ns
3.0 4.82
Error 12
2.117
0.176
Total 20
5.158
nsnot significant CV% = 22.17
SX = 0.24
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
97
APPENDIX TABLE 28. Analysis of variance for weight of marketable marble
tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.176
0.088
Treatment 6 0.333
0.055
0.88ns
3.0 4.82
Error 12
0.753
0.063
Total 20
1.262
nsnot significant CV% = 16.32
SX = 0.14
APPENDIX TABLE 29. Analysis of variance for weight of non-marketable
tubers per plot (kg).
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.008
0.004
Treatment 6 0.022
0.004
1.02ns
3.0 4.82
Error 12
0.042
0.004
Total 20
0.072
nsnot significant CV% = 4.95
SX = 0.03
APPENDIX TABLE 30. Analysis of variance for total yield per plot (kg)
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 2.092
1.046
Treatment 6
48.632
8.105
14.19** 3.0
4.82
Error 12
6.854
0.571
Total 20
57.578
** Highly significant CV% = 26.70
SX = 0.44
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
98
APPENDIX TABLE 31. Analysis of variance for yield tons/ha
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR F
VARIATION
FREEDOM
SQUARE
SQUARE
F
.05 .01
Replication 2 21.542
10.771
Treatment 6
135.754
22.626
7.31** 3.0
4.82
Error 12
37.117
3.093
Total 20
194.413
** Highly significant CV% = 29.74
SX = 1.01
APPENDIX TABLE 32. Analysis of variance for dry matter content of leaves
at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 82.608
41.304
Treatment 6
74.864.
12.477
2.33ns 3.0
4.82
Error 12
64.284
5.357
Total 20
221.756
nsnot significant CV% = 17.16
SX = 1.34
APPENDIX TABLE 33. Analysis of variance for dry matter content of leaves
at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 266.661
133.330
Treatment 6
236.292
39.382
1.91ns
3.0 4.82
Error 12
246.938
20.578
Total 20
749.891
nsnot significant CV% = 27.09
SX = 2.62
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
99
APPENDIX TABLE 34. Analysis of variance for dry matter content of leaves
at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication
2
96.538
48.269
Treatment 6
1119.201
186.534
6.09**
3.0 4.82
Error
12
367.475 30.623
Total 20
1583.214
** Highly significant CV% = 18.89
SX = 3.19
APPENDIX TABLE 35. Analysis of variance for dry matter content of leaves
at 90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 170.217
85.108
Treatment 6
1422.506
237.084
10.57**
3.0 4.82
Error 12
269.221
22.435
Total 20
1861.221
**Highly significant CV% = 24.94
SX = 10.60
APPENDIX TABLE 36. Analysis of variance for dry matter content of stems at
45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 340.382
170.191
Treatment 6
112.389
18.731
0.48ns 3.0
4.82
Error 12
472.442
39.370
Total 20
925.213
nsnot significant CV% = 22.83
SX = 3.62
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
100
APPENDIX TABLE 37. Analysis of variance for dry matter content of stems at
60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 65.084
32.542
Treatment 6
91.710
15.285
1.08ns 3.0
4.82
Error 12
169.768
14.147
Total 20
326.562
nsnot significant CV% = 15.43
SX = 2.17
APPENDIX TABLE 38. Analysis of variance for dry matter content of stems at
75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 77.493
38.747
Treatment 6
1734.945
289.157
2.68ns 3.0
4.82
Error 12
1294.393
107.866
Total 20
3106.831
nsnot significant CV% = 16.11
SX = 2.20
APPENDIX TABLE 39. Analysis of variance for dry matter content of stems at
90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 77.493
38.747
Treatment 6
1734.945
289.157
2.68ns
3.0 4.82
Error 12
1294.393
107.866
Total 20
3106.831
ns not significant CV% = 24.44
SX = 5.99
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
101
APPENDIX TABLE 40. Analysis of variance for dry matter content of roots
and stolons at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 72.317
36.159
Treatment 6
361.091
60.182
2.14ns
3.0 4.82
Error 12
336.808
28.067
Total 20
770.216
nsnot significant CV% = 23.06
SX = 3.06
APPENDIX TABLE 41. Analysis of variance for dry matter content of roots
and stolons at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 116.721
58.361
Treatment 6
372.525
62.087
0.68ns 3.0
4.82
Error 12
1093.900
91.158
Total 20
1583.146
nsnot significant CV% = 5.94
SX = 5.51
APPENDIX TABLE 42. Analysis of variance for dry matter content of roots
and stolons at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 932.340
466.170
Treatment 6
1148.414
191.402
3.56* 3.0
4.82
Error 2
646.001
53.833
Total 20
2726.755
*Significant CV% = 22.40
SX = 4.24
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
102
APPENDIX TABLE 43. Analysis of variance for dry matter content of roots
and stolons at 90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 150.321
75.161
Treatment 6
1970.644
378.444
2.01* 3.0
4.82
Error 12
1955.978
162.998
Total 20
4076.963
ns not significant CV% = 11.70
SX = 7.37
APPENDIX TABLE 44. Analysis of variance for dry matter content of tubers
at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 139.803
69.902
Treatment 6
286.771
47.795
1.14ns
3.0 4.82
Error 12
503.002
41.917
Total 20
929.576
nsnot significant CV% = 23.39
SX = 3.74
APPENDIX TABLE 45. Analysis of variance for dry matter content of tubers
at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 6.963
3.481
Treatment 6
74.500
12.417
1.77ns 3.0
4.82
Error 12
84.226
7.019
Total 20
165.689
nsnot significant CV% = 13.52
SX = 1.53
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
103
APPENDIX TABLE 46. Analysis of variance for dry matter content of tubers at
75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.800
0.400
Treatment 6
104.373
17.395
6.26**
3.0 4.82
Error 12
33.354
2.779
Total 20
138.527
nsnot significant CV% = 7.61
SX = 0.96
APPENDIX TABLE 47. Analysis of variance for dry matter content of tubers at
90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 20.425
10.212
Treatment 6
339.351
56.558
2.89ns 3.0
4.82
Error 12
234.458
19.538
Total 20
594.234
nsnot significant CV% = 21.79
SX = 2.55
APPENDIX TABLE 48. Analysis of variance for harvest index at 45 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.010
0.005
Treatment 6 0.150
0.025
1.12ns
3.0 4.82
Error 12
0.267
0.022
Total 20
0.427
nsnot significant CV% = 9.53
SX = 0.09
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
104
APPENDIX TABLE 49. Analysis of variance for harvest index at 60 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.004
0.002
Treatment 6 0.022
0.004
0.27ns 3.0
4.82
Error 12
0.166
0.014
Total 20
0.193
nsnot significant CV% = 26.73
SX = 0.07
APPENDIX TABLE 50. Analysis of variance of harvest index at 75 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.057
0.029
Treatment 6 0.582
0.097
7.06**
3.0 4.82
Error 12
0.165
0.014
Total 20
0.803
nsnot significant CV% = 29.32
SX = 0.07
APPENDIX TABLE 51. Analysis of variance for harvest index at 90 DAP
SOURCE OF
DEGREE OF
SUM OF
MEAN
COMPUTED
TABULAR
VARIATION
FREEDOM
SQUARE
SQUARE
F
F
.05 .01
Replication 2 0.003
0.001
Treatment 6 0.543
0.090
10.8** 3.0
4.82
Error 12
0.107
0.009
Total 20
0.652
**Highly significant CV% = 5.83
SX = 0.05
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
105
BIOGRAPHICAL SKETCH
The author was born to Mr. Luis Kios Senior and Mrs. Gina Camolo Kios
on January 20, 1957 in Lubas, La Trinidad, Benguet.
She completed her elementary education at Lubas Elementary School at
La Trinidad, Benguet. She finished her secondary education at San Jose High
school. She continued her college education at Mountain State Agricultural
College (MSAC) and finished with a degree of Bachelor of Science in Forestry.
In 1985 she pursued her Master's degree major in Horticulture and minor in
Extension in the same school now Benguet State University (BSU) and was able
to finish in 1992.
She is presently working as a Researcher at the Northern Philippine Root
Crop Research and Training Center (NPRCRTC) based at Benguet State
University under the Crop Improvement Department.
She was a widow with three children in 1984: Denver, Donna and
Douglas Jr. and in 1989 she got married to Mr. Antonio Simongo and blessed
with one beautiful daughter Antonette.
DONITA K. SIMONGO
Growth, yield and dry matter partitioning of potato genotypes under organic
production at La Trinidad, Benguet / Donita K. Simongo. 2007
Document Outline
- Growth, yield and dry matter partitioning
of potato genotypes under organic production at La Trinidad, Benguet
- BIBLIOGRAPHY
- ABSTRACT
- TABLE OF CONTENTS
- INTRODUCTION
- REVIEW OF LITERATURE
- MATERIALS AND METHODS
- RESULTS AND DISCUSSION
- SUMMARY, CONCLUSION AND RECOMMENDATION
- LITERATURE CITED
- APPENDICES
- BIOGRAPHICAL SKETCH