BIBLIOGRAPHY

ABES, DAISY A. APRIL 2008. Evaluation of Sweetpotato Varieties for Leaf
Tip Production Grown Under Organic System. Benguet State University, La Trinidad,
Benguet.
Adviser: Dr. Macario D. Cadatal
ABSTRACT

Seven sweetpotato varieties namely Comiles, Bengueta, Haponita, Tres Flores,
Kalbo-oy, Kuneing and PSBSP 17 were evaluated for leaf tips production.

All of the varieties evaluated showed no significant differences in terms of
percentage survival. Haponita and Kalbo-oy were observed to be the most vigorous
among the varieties evaluated. Varieties Comiles, Haponita and Kuneing were observed
to be moderately resistant to leaf scab infection. Comiles, Haponita, Tres Flores and
PSBSP 17 were moderately resistant to cutworm infestation.

In terms of number of leaf tips, Kalbo-oy had the most number of leaf tips
produced. Kalbo-oy was the most preferred among the varieties for general and market
acceptability.

In terms of profitability Kalbo-oy gave the highest return on cash expense
(ROCE).

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TABLE OF CONTENTS


Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ii

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
Varietal Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
Importance of Variety Evaluation in
Organic Farming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4

Nutritional Content of Sweetpotato Tops . . . . . . . . . . . . . . . . . . . . . . . . . .
4

Importance of Sweetpotato Tops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5

Importance of Chicken Manure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6

What is Organic Farming? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7

Use of Organic Fertilizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7

MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Plant Survival . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14

Plant Vigor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14

Reaction to Cutworm Infestation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15

Reaction to Leaf Scab Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15

Reaction to Stem Scab Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15

Average Number and Weight of
Leaf Tips of Sweetpotato . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
ii

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Sensory Evaluation/ Acceptability
of Leaf Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17

Market Acceptability of Leaf Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17

Cost and Return Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18

Soil Chemical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18

SUMMARY, CONCLUSION AND RECOMMENDATION . . . . . . . . . . . . . . . .
20
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21

Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21

LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24

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1
INTRODUCTION


Sweetpotato is a major subsistence crop in the Philippines. It is locally known as
“camote” and traditionally used as staple food by many mountain tribes especially in
areas where rice supply is low or not available. Every part of the sweetpotato is
consumed. The storage roots are eaten as food. The tender tops are eaten as vegetable
while mature vines are used as planting materials or animal feeds. It is considered as
“survival crop” restored by many Filipinos during calamities and food shortage. The
herbage are used as feeds for live stocks (NPRCRTC, 1990).
Sweetpotato is being grown for its storage roots and its tops or leaves that are also
nutritious. As human food the tender stems and leaves are used regularly as vegetables.
The leaves or the tops are excellent source of Vitamins A, B and C which may give a fuel
value of 1230 calories. The tops or leaves are excellent source of pro-vitamins A and
there by contributes in the prevention of Vitamin A deficiency (Yap, 1982).
It is also rich in carbohydrates and therefore contributes in the prevention of
vitamin deficiency. The tops can also address the problem of food nutrient deficiency
among people. The tops of sweetpotato can also be used as medicine like for example
the juice of purple leaves can be a remedy for diabetes and roasted roots for diarrhea
(Yap, 1982).
Sweetpotato leaf tips were used for many years as vegetables in rural and urban
areas. Planting these varieties could increase production if leaf tips as vegetables even in
a limited area. If these leaf tips will be brought to the market, it would mean an
additional increase for the growers. These leaf tips provide nutritious food for the
household.
Evaluation of Sweetpotato Varieties for Leaf Tip Production
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A primary importance of sweetpotato is through consumption, utilization and
nutrition. A salient question through Asia centers on why per capita sweetpotato
consumption is declining. Among people, the major nutritional problems could be
partially alleviated, through sweetpotato consumption. The major food problems center
in protein energy malnutrition, iron deficiency anemia, vitamin A deficiency and goiter or
iodine deficiency. Nutritional studies indicate that sweetpotato is a source to fight these
nutritional problems. So 100 g of sweetpotato tops (leaves) meets the daily requirements
for vitamin A and about one-third of daily iron requirements. There is a great potential of
sweetpotato farming in contributing food requirement of the people because it is
nutritious, palatable, easy to grown and has the ability to supply leaf tips for vegetables
within three weeks after planting (Trougn et al., 1988).
The economic potential of sweetpotato farming is now widely recognized not
only its storage roots but also for leaf tips which is also important in human diet. At
present, our farmers still adhere to subsistence agronomic practices. Therefore, the
present production of sweetpotato is very low. They should be made to explore cultural
techniques to increase production through the use of organic fertilizer. It is believed that
using the right kind and amount of organic fertilizer will increase the yield. Growing
sweetpotato organically might not be profitable but contribute to enhancing the quality
and conserving resources in the environment. Selection of suitable sweetpotato varieties
for organic production must be done. The importance of sweetpotato production is
viewed from the fact that it provides livelihood opportunities for 3-4 million people.
Evaluation of Sweetpotato Varieties for Leaf Tip Production
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The objectives of the study were to determine the performance of sweetpotato
varieties for leaf tip production and to identify the best sweetpotato variety for leaf tip
production grown under organic system.
The study was conducted at Benguet State University experimental area at Balili,
La Trinidad, Benguet from October 2007 to March 2008.


Evaluation of Sweetpotato Varieties for Leaf Tip Production
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4
REVIEW OF LITERATURE

Varietal Evaluation
Varietal evaluation is a process on crop breeding program which provides
comparison of promising lines with the local check in order to establish the superiority of
the lines developed by a breeder. It is only through varietal evaluation that developed
lines in terms of yield, quality, adaptation, stress, insect pest and diseases (Rasco and
Amante, 1994).
Evaluation is the first stage of a systemic variety evaluation process. It refers to
the assessment of the sustainability of potential cultivars to a given farming environment.
The work is normally done by a breeder who aims to determine if a new variety is better
than the local variety (Vergara, 1992).

Importance of Variety Evaluation in Organic Farming
Bautista and Mabesa (1997) cited that selecting the right variety would minimize
problem associated with water and fertilizer management. Varieties should be high
yielding, pest and disease resistant and early maturing so that production would entail
less expense and ensure more profit. HARRDEC (1996) stated that variety evaluation is
important in order to observe performance character such as yield, earliness, vigor
maturity and keeping quality.

Nutritional Content of Sweetpotato Tops
Yudelman (1985) revealed that this crop can be a good source of Vitamin A, C,
and iron (from the leaves) apart carbohydrates (from the roots). Consumption of
sweetpotato roots and of tops averages 0.80 kg and 410 g per week, respectively. The
Evaluation of Sweetpotato Varieties for Leaf Tip Production
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5
sweetpotato tops is good substitute for leafy vegetables which are good source of
vitamins and minerals.

Importance of Sweetpotato Tops
Most Filipino families particularly those leaving in the rural areas maintain a
garden where they get most of their vegetable needs. Sweetpotato is probably the only
vegetable that can be eaten by humans and animals. It is nutritious so man who eats 100
grams of tops a day gets his Vitamin A for about two days, one-quarter of his Vitamin B2
requirement, more than half of his Vitamin C and iron needs and some quantities of
calcium, ash and fiber.
Sweetpotato top production is ideal for undertaking in the urban or per urban
areas. It is often undertaken in a relatively large scale, say one hectare or bigger so that it
could really be profitable (AVRDC, 2007).
A survey made in Tacloban, Philippines showed that vegetable consumed 75 %
choose sweetpotato tops as the number one preferred vegetable primarily because it is
affordable and nutritious, 65 % of consumed sweetpotato tops two to five times a week
(Villamor, 1991).
Shading and fertilization significant affect shoot tip production but not the
pruning frequency. In general, more shoot tips produced with 50 % shading (Villamor,
1991).
According to (Villamor et al., 1979) for a particular characteristics, they could not
give a specific reason and said that actually any variety would do whether green or red,
degitate or heart-shaped. In terms of special desired characteristics method tenderness as
a preferred quality. He stated that acceptability of sweet potato tops should be tender,
Evaluation of Sweetpotato Varieties for Leaf Tip Production
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6
glabrous (not hairy) and purplish. However direct observation of camote tops in the
Tacloban market shows, that there are more purple than green varieties being sold.
Sweetpotato tips are also used for food. Cultivars that yield good tips are limited
and produce tips which have green and tender leaves. The tops or leaves are an excellent
source of nutrient as well as the tubers (AVRDC, 2007).
Wolfe (1992) stated that home gardens selection criteria in sweet potato are the
cultivar's herbage yield. Most farmers’ preference are the entries purposely because of
food consumption, livestock and young leaves as vegetables.

Importance of Chicken Manure

Sung-ag (1997) found that plants fertilized with chicken manure significantly
increased the number of productive tillers, length of panicles, plant height at maturity and
harvest index. He furthers that chicken manure seems to be the best among the organic
materials as source of organic fertilizer to effect increase in yield of high yielding
varieties of rice (HYV).

Daoines (1994) found that in applying organic matter like chicken manure
improve soil structure. This may due to the presence of nutrient in the organic matter.
He also mentioned that C:N ratio might indicate the availability of N in organic matter
since the lower the C:N the better is the availability of nitrogen.

Watts (1972) stated that chicken manure is the most valuable for garden purposes.
It contains a large percentage of phosphoric acid and it is especially rich in nitrogen. It
has been regarded as the best fertilizer as for other garden crops requiring a large amount
of nitrogen.

Evaluation of Sweetpotato Varieties for Leaf Tip Production
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What is Organic Farming?
Organic farming system avoids the use of the synthetic fertilizers, pesticides and
growth regulators. Instead they rely on crop rotations, crop residues, animal manures, off
farm wastes, mechanical cultivation, mineral bearing rocks and biological pest control to
maintain soil health, supply plant nutrients and minimize insects, weed and other pest
(Sullivan, 2003).
Organic farming as a modem, sustainable fanning system which maintains the
long-term fertility of soil and use less of the Earth's finite resources to produce high
quality and nutritious food. It advocates the critical connections between health of the
soil, health of people and health of society (Kristiansen et al., 2006).

Use of Organic Fertilizers
Several studies revealed that application of organic fertilizer in proper amounts
can help meet the nutritional level requirement of the plant. Aside from that, it also
increases the plant nutrients and improves the physical condition of the soil. Continuous
use of organic fertilizer does not make the soil acidic as does the constant use of
inorganic fertilizer (Kinoshita, 1977).
Manure is an effective source of nutrients for most crops. However those crops
with relatively high nitrogen requirements such as corn, sorghum, and vegetables are
most likely to respond to its application. Application animal manure is very important
because they contain nutrients (Brady, 1985).

Evaluation of Sweetpotato Varieties for Leaf Tip Production
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MATERIALS AND METHODS


Land Preparation and Experimental Design

The materials used were sweetpotato stem cuttings from different varieties,
chicken manure was applied or incorporated to the soil.

An area of 105 sq. m was thoroughly prepared and divided into 3 blocks. Each
block was composed of seven plots each measuring 1 m x 5 m which accommodated the
different sweetpotato varieties. The organic fertilizer was applied two weeks before
planting.

Before and after planting, soil samples from the experimental area were collected
for chemical analysis to determine the initial fertility such as OM, pH, N, P and K
content.

The experiment was laid out using the randomized completely block design
(RCBD) replicated three times.

Planting Materials

Sweetpotato stem cuttings from different varieties was taken from the Northern
Philippines Root Crops Research and Training Center (NPRCRTC), BSU La Trinidad,
Benguet. The varieties taken were: Comiles, Bengueta, Haponita, Tres Flores, Kalbo-oy
and PSBSP 17. The Kuneing variety was taken at Tinongdan, Itogon, Benguet.
Sweetpotato stem cutting were secured from the matured plants measuring 35 cm.




Evaluation of Sweetpotato Varieties for Leaf Tip Production
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Planting Distance
Sweetpotato cuttings with full length of 35 cm were planted in slanting position.
Cuttings were planted in double rows at one cutting per hill with a distance of 40 cm
between hills and 40 cm between rows.

Cultural Management

All the necessary cultural practices, such as proper irrigation, weeding practices
and pest control were done to maintain the growth and yield of sweetpotato. Weeding
and cultivation were done before the vines become too long and before they cover the
space between the rows. Regular weeding was done and the crops were irrigated as
necessary.

Topping Frequency
Topping was done in one month after planting then continued monthly. One foot
long or 30 cm long was gathered every topping.

Data Gathered
A. Growth Performance
1. Percentage survival (%). The number of plants that survived were counted at
30 days after planting. Percent survival was computed using the following formula:
number of plants survived
total number of plants planted
% survival =
x 100
2. Plant vigor. The plants were rated according to the following scale. This was
recorded at 80 days after planting. The CIP rating scale, as cited by Gonzales et al.
(2004), was used:
Evaluation of Sweetpotato Varieties for Leaf Tip Production
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SCALE DESCRIPTION REMARKS
1
Plants are weak with few stems and
Poor vigor
leaves; very pale

2
Plants are weak with few thin stems
Less vigorous
and leaves; pale

3
Better than less vigorous
Moderately vigorous

4
Plants are moderately strong with
Vigorous
robust stems and leaves; leaves are
light green in color

5
Plants are strong with robust stems
Highly vigorous
and leaves; leaves are light to dark
green in color

3. Top yield (kg). This was taken monthly harvest of the sweetpotato leaf tips
from the ten sample plants from each treatment per replication were cut and weighed.
4. Pest and disease rating. Common pest and disease of sweetpotato was rated
using the one to five scales in increasing order of severity.
a. Rating scale for insect damage (cutworm) (Rasco, 1996).
SCALE DESCRIPTION REACTION
1
Light infestation
Very resistant
2
Medium light infestation
Resistant
3 Medium
infestation
Moderately
resistant
4
Medium heavy infestation
Moderately susceptible
5 Heavy
infestation
Susceptible
b. Rating scale for disease (scab). Leaf scab infestation of the ten sample
plants from each. Variety was rated one month after planting up to one month before
harvesting using the following scale (Rasco, 1996).
Evaluation of Sweetpotato Varieties for Leaf Tip Production
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SCALE DESCRIPTION REACTION
5
Lesions on leaves and stem
Susceptible
coalesced. Severe leaf deformation
and stem twisting

4
Several lesions on leaves and stems,
Moderately susceptible
lesions coalesced with slight stem
deformation

3
Several lesions on leaves and stems
Moderately resistant
no stem deformation

2
Few lesions on leaves and stems; no
Resistant
stem deformation

1
No symptom
Highly/ Very resistant

c. Stem scab
SCALE DESCRIPTION REACTION
1
No symptom
Highly resistant
2
1-25 % infection
Resistant
3
25-50 % infection
Susceptible
4
50-75 % infection
Moderately susceptible
5
75-100 % infection
Highly susceptible

B. Yield and Yield Components
1. Number and weight of leaf tips (kg). These were obtained by counting and
weighting the tops gathered from each variety per replication.
C. Cost and Return Analysis
The production cost was properly recorded. This includes the gross sales, net
return, (material inputs, labors and marketing). The return on cash expense (ROCE) was
computed using the following formula.
Evaluation of Sweetpotato Varieties for Leaf Tip Production
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Gross sales – Total expenses


Total
ROCE =
expenses x 100


D. Sensory Evaluation
After getting all the data from the leaf tips gathered from the first topping, the
tops were cooked by means of boiling in the same amount of water. The boiling of
sweetpotato tops of each variety were boiled at 10 to 15 minutes at the same time. At
least twenty of the students from the BSU ladies dormitory were the panelist. The
sweetpotato tops were evaluated according to its appearance, color, texture, flavor and
general acceptability from each variety. The following were rated using the 1-5 scale
(Gonzales and Dati, 1994).
SCALE DESCRIPTION
1 Dislike
very
much
2
Neither like nor dislike
3 Like
slightly
4 Like
moderately
5 Like
extremely

E. Market Acceptability
Consumer’s perception on the different tips was recorded. The characteristics of
the varieties selected were noted and buyers were asked the reason for selecting a
certained variety (Soliba et al., 2004). Comments of the buyers was recorded or
documented and they are free to select the variety of their choice.


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F. Chemical Properties of the Soil

The pH, organic matter, nitrogen, phosphorous and potassium of the soil were
gathered before planting and after harvesting through soil analysis at the Bureau of Soil;
Aguila Road, San Fernando City, La Union.
G. Data Analysis
Data was statistically analyzed using analysis of variance for randomized
completely block design. Significance of difference between treatments were tested
using the Duncan’s Multiple Range Test (DMRT).






Evaluation of Sweetpotato Varieties for Leaf Tip Production
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RESULTS AND DISCUSSION


Plant Survival

Percent survival of the seven sweetpotato varieties evaluated is presented in Table
1. 100 % survival was recorded from varieties; Comiles, Bengueta, Haponita, Kuneing
and PSBSP 17. Variety Kalbo-oy and Tres Flores had 99 % plant survival.

Plant Vigor

Plant vigor of seven sweetpotato varieties evaluated ranged from moderately
vigorous to highly vigorous. Variety Haponita and Kalbo-oy were rated highly vigorous
with Tres Flores as moderately vigorous. Majority of the varieties had a vigorous plant
growth performance.

Table 1. Percentage survival (30 DAP) and plant vigor (80 DAP) of seven varieties of
sweetpotato

SURVIVAL
VARIETY
PLANT VIGOR*
(%)
Comiles 100
4
Bengueta 100
4

Haponita 100
5
Tres Flores
99
3
Kalbo-oy 99
5
Kuneing 100
4
PSBSP 17
100
4
CV (%)
0 .97

*Rating scale (1-5): 1– Poor vigor, 2 – Less vigorous, 3 – Moderately vigorous, 4
– Vigorous, 5 – Highly vigorous


Evaluation of Sweetpotato Varieties for Leaf Tip Production
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Reaction to Cutworm Infestation
The Table 2 shows the cutworm infestation rating from 3.0 to 4.0. Bengueta,
Kuneing and Kalbo-oy were moderately susceptible to cutworm infestation. Varieties
Comiles, Haponita, Tres Flores and PSBSP 17 were rated moderately resistant.

Reaction to Leaf Scab Infection

Table 2 shows the leaf scab infection ranging from 3.0 to 4.0. It was observed
that both Comiles and Haponita were moderately resistant to leaf scab infection while
varieties Bengueta, Tres Flores, Kuneing and PSBSP 17 were moderately susceptible to
leaf scab occurrence.

Reaction to Stem Scab Infection
Table 2 shows that varieties Comiles and Haponita were observed to be resistant
to stem scab. Moderately resistant reaction were observed among Bengueta, Tres Flores,
Kalbo-oy, Kuneing and PSBSP 17.

Table 2. Reaction of seven varieties of sweetpotato to cutworm infestation, leaf scab
infection and stem scab infection

CUTWORM
LEAF SCAB
STEM SCAB
VARIETY
INFESTATION
INFECTION
INFECTION
Comiles
3.0 3.0 2.0
Bengueta 4.0 4.0 3.0
Haponita 3.0 3.0 2.0
Tres
Flores 3.0 4.0 3.0
Kalbo-oy 4.0 4.0 3.0
Kuneing
4.0 4.0 3.0
PSBSP
17 3.0 4.0 3.0
*1 – Very resistant, 2 – Resistant, 3 – Moderately resistant, 4 – Moderately susceptible, 5 –
Susceptible
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Average Number and Weight of
Leaf Tips of Sweetpotato


Table 3 shows the average total number and weight of leaf tips produced from the
three times harvest. Kalbo-oy produced the most numerous leaf tips and based on the
statistical analysis it obtained the highest mean of 85 which is highly significant among
the other varieties evaluated. On the other hand, Haponita obtained the lowest number of
leaf tips (25) but comparable to Tres Flores. In terms of weight, Kalbo-oy produced the
highest mean of 0.72 kg respectively. The lowest weight of leaf tips was obtained by
Tres Flores variety but comparable to Haponita. Such highly significant differences
among the varieties could be attributed to their varietal characteristics and environmental
conditions.

Table 3. Number and weight of leaf tips of seven varieties of sweetpotato
WEIGHT
VARIETY NUMBER*
(kg)
Comiles 49
bc
0.64 ab
Bengueta 45c
0.54 b
Haponita 25d
0.36 c
Tres Flores
33d
0.35 c
Kalbo-oy 85a
0.72 a
Kuneing 61b
0.66 ab
PSBSP 17
53bc
0.60 ab
CV (%)
13.56
13.84
*Means with the same letter are not significantly different at 5 % DMRT






Evaluation of Sweetpotato Varieties for Leaf Tip Production
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Sensory Evaluation/ Acceptability
of Leaf Tips

Table 4 shows that varieties Kalbo-oy and Kuneing were both rated as like
extremely in terms of sensory acceptability. Varieties Comiles, Tres Flores, PSBSP 17
and Haponita were rated like moderately, rated as like slightly. This shows that the six
varieties were all acceptable in terms of sensory acceptability due to their green and
tender young leaves. The higher the acceptability, the better is the eating quality as
vegetables.

Market Acceptability of Leaf Tips
Table 5 shows the market acceptability of leaf tips from the varieties evaluated.
The results follow that of the sensory evaluation variety Kalbo-oy and Kuneing were
rated as liked extremely by the buyers (panelist).

Table 4. Sensory evaluation of leaf tips of seven varieties of sweetpotato
GENERAL
VARIETY APPEARANCE COLOR
FLAVOR TEXTURE ACCEPTABILITY
Comiles
Like
Like
Like
Like
Like moderately
moderately
moderately
moderately
moderately

Bengueta
Like slightly
Like
Like slightly
Like slightly Like slightly
slightly

Haponita
Like
Like
Like
Like slightly Like moderately
moderately
moderately
moderately


Tres Flores
Like
Like
Like
Like
Like moderately
moderately
moderately
moderately
moderately

Kalbo-oy
Like
Like
Like
Like slightly Like extremely
moderately
moderately
extremely


Kuneing
Like
Like
Like
Like
Like extremely
moderately
moderately
moderately
moderately

PSBSP 17
Like
Like
Like
Like slightly Like moderately
moderately
moderately
moderately

Evaluation of Sweetpotato Varieties for Leaf Tip Production
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Table 5. Market acceptability of leaf tips of seven varieties of sweetpotato
GENERAL
VARIETY
TENDERNESS COLOR
TEXTURE
APPEARANCE ACCEPTABILITY
Comiles
Like moderately Like
Like moderately Like
Like moderately
moderately
moderately

Bengueta Like slightly
Like slightly Like slightly
Like slightly
Like slightly


Haponita
Neither like nor
Like slightly Like slightly
Like
Like moderately
dislike
moderately

Tres
Like slightly
Like
Like moderately
Like
Like moderately
Flores
moderately
moderately

Kalbo-oy Like extremely
Like
Like extremely
Like
Like extremely
extremely

moderately

Kuneing
Like extremely
Like
Like moderately Like
Like extremely
moderately
moderately

PSBSP 17 Like moderately Like
Like slightly
Like
Like moderately
moderately
moderately

Cost and Return Analysis

Table 6 shows the return on cash expense (ROCE) of sweetpotato leaf tips
production. The results showed that Kalbo-oy variety had the highest return on cash
expense on leaf tips produced. The other varieties evaluated showed a negative (ROCE)
due to low yield of the varieties evaluated.

Soil Chemical Properties

The initial and final analysis of the soil taken from the experimental area are
shown in Table 7.

The initial pH of the soil was 6.3 with organic matter content of 2.5 %. The
nitrogen, phosphorous and potassium content of the soil are 0.12 %, 100 ppm and 340
ppm, respectively.


Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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19
Table 6. Cost and return analysis based on leaf tip yield

VARIABLE COST
YIELD
GROSS
TOTAL
NET
TREATMENT
LABOR FERTILIZER
TIPS
SALES
EXPENSES
ROCE
INCOME
COST
COST
(kg)
(PhP)
(PhP)
Comiles 161 71 1.95
234.00
246.00
-12.00
-4.87
Bengueta 161 71 1.65
173.25
246.00
-72.75
-29.57
Haponita 161 71 1.25
93.75
246.00
-152.25
-61.89
Tres Flores
161
71
1.21
90.00
246.00
-156.00 -63.89
Kalbo-oy 161 71 2.96
534.60
246.00
288.60
117.31
Kuneing 161 71 1.97
236.40
246.00
-9.60
-3.90
PSBSP 17
161
71
1.85
194.25
246.00
-51.75 -21.04
• The variable cost includes = (labor and fertilizer cost)
• Based at 15.00 /bundle = (per bundle composed of 250 g)
• Chicken manure = PhP 100.00 / sacks


The soil applied with chicken manure had an increased soil pH. This confirms the
findings of Watts (1972) that application of chicken manure would increased the pH level
of the soil, organic matter content of the soil and this could be due to the addition of
organic materials. The phosphorous content of the soil had increased from 100 ppm to
160 ppm. The potassium content of the soil had increased from 340 ppm to 422 ppm.

Table 7. Soil analysis before and after planting


OM
N
P
K
pH
(%)
(%)
(ppm)
(ppm)
Before planting
6.3
2.5
0.12
100
340
After planting
6.4
2.5
0.14
160
422
Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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20
SUMMARY, CONCLUSION AND RECOMMENDATION


Summary

The study was conducted to evaluate seven sweetpotato varieties for leaf tips
production grown under organic system at the Balili Experimental Station, Benguet State
University. The different varieties used were Comiles, Tres Flores, Haponita, Bengueta,
Kalbo-oy, Kuneing and PSBSP 17. Findings revealed that the different varieties shows
no significant differences in terms of percentage survival at 30 days after planting, plant
vigor, cutworm infestation, leaf scab infection and stem scab infection. Numerically,
however, variety Haponita and Kalbo-oy were both observed to be highly vigorous
among the seven varieties evaluated.

There are no varieties found to be resistant to cutworm infestation. Varieties
Comiles, Haponita, Tres Flores, PSBSP 17 were moderately resistant and the other
varieties were observed to be moderately susceptible. In terms of leaf scab infection,
both Comiles and Haponita were observed to be moderately resistant while the other
varieties were moderately susceptible. However, variety Haponita and Comiles are both
resistant to stem scab infection.

In terms of number and weight of leaf tips, numerically, Kalbo-oy variety
produced the most numerous number and heaviest leaf tips (0.72 kg).

As to general acceptability of leaf tips, the panelists preferred most Kalbo-oy and
Kuneing. Varieties Comiles, Haponita, Tres Flores and PSBSP 17 were liked
moderately. Variety Bengueta was liked slightly.

In terms of profitability Kalbo-oy gave the highest ROCE of leaf tips followed by
Kuneing and comparable to Comiles, Tres Flores and PSBSP 17.
Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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21
Conclusion
Variety
Kalbo-oy proved to be good for leaf tip production. It is most preferred in
the market and is profitable to produce.

Recommendation

Under the condition of the study, variety Kalbo-oy is highly recommended for
leaf tips production.








Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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22

LITERATURE CITED

ANON, 1973. Sweet potato, easy to grow. Communication Center Nayon Pilipino, Mia
Avenue, Pasay City, P.5.

AVRDC, 2007. Sweetpotato, proceedings of the first international symposium. Manila
Bulletin. Pp. 16-17.

BALIGOD, J. 2004. Evaluation of sweet potato varities for storage yield and leaf tips as
vegetables. BS Thesis. BSU La Trinidad, Benguet. Pp. 8-9.

BAUTISTA, O. K. and R. MABESSA, 1977. Vegetable production. College Laguna
(UPLB-CA) University of the Philippines at Los Baños. College of Agriculture.
P. 28.

BRADY, T. 1985. A preliminary investigation into the effects of leaf distribution of the
yields of sweetpotato. Pp. 6-7.

GONZALES, I. C. 1983. Sweetpotato in highlands. Research and Extension Newsletter.
B.T.I. Baguio In Highland Express, HARC, BSU La Trinidad, Benguet. Vol. 1 P.
6.

KINOSHITA, S. 1977. Evaluation of Philippine Schools. 1st Ed. Alemar-Phonex
Publishing, Quezon City, Philippines. P.8.

KRISTIANSEN, P. and J. REGANOLD. 2006. Organic agriculture. A global respective.
Collingwood V.I.C., Australia. Pp. 222-223.

NPRCRTC, 1990. Rapid rural appraisal on sweetpotato areas of Benguet. NPRCRTC-
BSU La Trinidad, Benguet. Pp. 6-8.

RASCO, E. T. and V. T. AMANTE. 1994. Sweetpotato variety evaluation Southeast
Asia Program for Potato Research and Development (SAPRAD) Pp. 5-6.

SULLIVAN, E. 2003. Evaluation of sweetpotato processing of the First International
Symposium. AVRDC, Taiwan. Pp. 134-136.

SUNG-AG, R. A. 1997. Effect of different animal manures on the growth and yield of
HYV rice under Poblacion, San Gabriel, La Union conditions. BS Thesis. BSU La
Trinidad, Benguet. P. 33.

UPWARD. 1991. Sweetpotato cultures of Asia and South Pacific Asia. UPWARD.
Search Auditorium, UPLB. Campus College, Laguna, Philippines. Pp. 134-135.

Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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23
VERGARA, B. S. 1992. A farmers’ primer in growing rice. International Rice Research
Institute. Los Baños, Laguna, Philippines P. 16.

VILLAMOR, F. G. 1991. Camote tops pot of garden for the slum swelter of Tacloban.
Paper presented during the 2nd International Symposium on sweetpotato. SEAR
CA, College, Laguna. Pp. 64.

WATTS, R. C. 1972. Vegetative gardening. New York: Orange Judd Publishing Co. P.
38.

WOLFE, J. A. 1992. Sweetpotato. An untopped food resource network highlight.
PCARRD. Los Baños, Laguna. Pp. 11 - 12.

YAP, M. T. 1982. Yield evaluation of three sweetpotato cultivars using two harvesting
methods. BS Thesis. MSAC La Trinidad, Benguet. P. 1.

YUDELMAN, J. 1985. The nutrition factor of a bio-intensive garden, IMR, Silang
Cavite. Pp. 34-38.





Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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APPENDICES


APPENDIX TABLE 1. Plant survival (%)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 100
100
100
300
100
Bengueta 100
100
100
300
100
Haponita 100
100
100
300
100
Tres Flores
100
100
97
297
99
Kalbo-oy 100
97
100
297
99
Kuneing 100
100
100
300
100
PSBSP 17
100
100
100
300
100
TOTAL 700
697
697
2,
094
698


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
OF
COMPUTED F
F
VARIANCE
SQUARES
SQUARE
FREEDOM
0.05 0.01
Replication 2
0.857
0.429

Treatment 6
4.286
0.714
0.77ns 3.0 4.82
Error 12
11.143
0.929

Total 20
16.286

ns–Not significant
CV (%) =0.97

Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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25
APPENDIX TABLE 2. Plant vigor

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 5
4
3
12
4.00
Bengueta 4
4
4
12
4.00
Haponita 5
5
4
14
4.67
Tres Flores
3
4
3
10
3.33
Kalbo-oy 4
5
5
14
4.67
Kuneing 4
4
4
12
4.00
PSBSP 17
3
4
4
11
3.67
TOTAL 28
30
27
85
28.34


APPENDIX TABLE 3. Pest incidence (cutworm damage)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 3
2
3
8
2.67
Bengueta 3
4
5
12
4.00
Haponita 4
3
3
10
3.33
Tres Flores
3
3
3
9
3.00
Kalbo-oy 3
5
4
12
4.00
Kuneing 3
4
4
11
3.67
PSBSP 17
4
3
3
10
3.33
TOTAL
23
24
25
76
24.00



Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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26
APPENDIX TABLE 4. Leaf scab incidence

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 4
3
3
10
3.33
Bengueta 4
5
4
13
4.33
Haponita 3
4
3
10
3.33
Tres Flores
5
4
3
12
4.00
Kalbo-oy 4
4
5
13
4.33
Kuneing 4
4
3
11
3.67
PSBSP 17
3
4
5
12
4.00
TOTAL 27
28
25
81
26.99


APPENDIX TABLE 5. Stem scab incidence

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 3
2
2
7
2.33
Bengueta 2
3
3
8
2.67
Haponita 2
2
3
7
2.33
Tres Flores
3
3
3
9
3.00
Kalbo-oy 4
2
3
9
3.00
Kuneing 3
4
3
10
3.33
PSBSP 17
3
2
3
9
3.00
TOTAL 20
18
20
59
19.66



Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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27
APPENDIX TABLE 6. Number of leaf tips (first harvest)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 34
37
20
91
30bb
Bengueta 28
27
41
96
32bb
Haponita 4
11
20
35
12 cd
Tres Flores
7
20
5
32
11 d
Kalbo-oy 53
76
44
173
58 a
Kuneing 26
30
26
82
27 bc
PSBSP 17
22
25
23
70
23 bcd
TOTAL 174
226
179
579
28


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
COMPUTED
OF
F
VARIANCE
SQUARES
SQUARE
F
FREEDOM
0.05 0.01
Replication 2
235.143
117.571

Treatment 6
4,469.143
744.557
10.24** 3.0 4.82
Error 12
872.857
72.738

Total 20
5,577.143

**–Highly significant
CV (%) =30.93



Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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28
APPENDIX TABLE 7. Weight (kg) of leaf tips (first harvest)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 0.770
0.790
0.490
2.050
0.683bab
Bengueta 0.452
0.470
0.740
1.662
0.554bab
Haponita 0.094
0.186
0.412
0.692
0.231 c
Tres Flores
0.151
0.360
0.121
0.632
0.211 c
Kalbo-oy 0.748
0.806
0.548
2.102
0.701 a
Kuneing 0.345
0.566
0.520
1.431
0.477 b
PSBSP 17
0.475
0.584
0.540
1.599
0.533 b
TOTAL 3.035
3.762
3.371
10.259
0.488


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
COMPUTED
OF
F
VARIANCE
SQUARES
SQUARE
F
FREEDOM
0.05 0.01
Replication 2
0.030
0.019
Treatment 6
0.699
0.116
6.13** 3.0 4.82
Error 12
0.228
0.019

Total 20
0.964


**–Highly significant
CV (%) =28.46


Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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29
APPENDIX TABLE 8. Number of leaf tips (second harvest)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 77
79
63
219
73bb
Bengueta 62
64
55
181
60 b
Haponita 32
41
39
112
37 c
Tres Flores
46
58
56
160
53 bc
Kalbo-oy 103
146
89
338
113 a
Kuneing 54
62
68
184
61 b
PSBSP 17
66
66
77
209
70 b
TOTAL 440
516
447
1,403
67


ANALYSIS OF VARIANCE

TABULATED
SOURCE OF
DEGREES OF
SUM OF
MEAN
COMPUTED
F
VARIANCE
FREEDOM
SQUARES
SQUARE
F
0.05 0.01
Replication 2 504.095
252.048

Treatment 6
9,815.238 1,635.673
10.24** 3.0 4.82
Error 12
1,763.905
146.992

Total 20
12,083.238

**–Highly significant
CV (%) =18.15



Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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30
APPENDIX TABLE 9. Weight (kg) of leaf tips (second harvest)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 0.61
0.92
0.85
2.38
0.79 abc
Bengueta 0.57
0.52
0.64
1.73
0.58 bcd
Haponita 0.41
052
0.45
1.38
0.46 d
Tres Flores
0.51
0.58
0.56
1.65
0.55 cd
Kalbo-oy 0.85
1.14
0.60
2.59
0.86 a
Kuneing 0.52
0.64
0.95
2.11
0.70 abcd
PSBSP 17
0.82
0.86
0.83
2.51
0.84 ab
TOTAL 4.29
5.08
4.88
14.35
0.68


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
COMPUTED
OF
F
VARIANCE
SQUARES
SQUARE
F
FREEDOM
0.05 0.01
Replication 2
0.059
0.029
Treatment 6
0.442
0.074
3.46** 3.0 4.82
Error 12
0.256
0.021

Total 20
0.767


**– Highly significant
CV (%) =21.36



Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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31
APPENDIX TABLE 10. Number of leaf tips (third harvest)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 44
39
42
125
42 cd
Bengueta 40
47
55
142
47 bc
Haponita 31
23
26
80
27 d
Tres Flores
35
29
42
106
35 c
Kalbo-oy 98
72
87
257
86 a
Kuneing 115
89
76
280
93 a
PSBSP 17
63
51
82
196
65 b
TOTAL 426
350
410
1,186
56


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
COMPUTED
OF
F
VARIANCE
SQUARES
SQUARE
F
FREEDOM
0.05 0.01
Replication 2
450.667
229.333
Treatment 6
11,782.571 1,963.762
16.81** 3.0 4.82
Error 12
1,402.000
116.833

Total 20



**–Highly significant
CV (%) =19.14

Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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32
APPENDIX TABLE 11. Weight (kg) of leaf tips (third harvest)

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 0.52
0.41
038
1.31
0.44ccd
Bengueta 0.52
0.46
0.57
1.55
0.52 bc
Haponita 0.46
0.33
0.39
1.18
0.39 c
Tres Flores
0.30
0.21
0.41
0.92
0.31 d
Kalbo-oy 0.68
0.52
0.59
1.79
0.60 b
Kuneing 0.89
0.76
0.68
2.33
0.78 a
PSBSP 17
0.38
0.32
0.60
1.30
0.43 c
TOTAL 3.75
3.01
3.62
10.38
0.49


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
COMPUTED
OF
F
VARIANCE
SQUARES
SQUARE
F
FREEDOM
0.05 0.01
Replication 2
0.045
0.022
Treatment 6
0.429
0.072
10.78** 3.0 4.82
Error 12
0.080
0.007

Total 20



**–Highly significant
CV (%) =16.48

Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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33
APPENDIX TABLE 12. Average number of leaf tips

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 52
52
42
146
49 bc
Bengueta 43
46
50
139
46 c
Haponita 22
25
28
75
25 d
Tres Flores
29
36
34
99
33 d
Kalbo-oy 85
98
73
256
85 a
Kuneing 65
60
57
182
61 b
PSBSP 17
50
47
61
158
53 bc
TOTAL 346
317
345
1,055
352


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
COMPUTED
OF
F
VARIANCE
SQUARES
SQUARE
F
FREEDOM
0.05 0.01
Replication 2
32.667
16.333
Treatment 6
6,894.476
1,149.079
24.77** 3.0 4.82
Error 12
556.667
43.389

Total 20
7,483.810


**–Highly significant
CV (%) =13.56

Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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34
APPENDIX TABLE 13. Average weight (kg) of leaf tips

REPLICATION
VARIETY
TOTAL MEAN
I II III
Comiles 0.63
0.71
0.57
1.91
0.64 ab
Bengueta 0.51
0.48
0.65
1.64
0.55 b
Haponita 0.32
0.35
0.42
1.09
0.36 c
Tres Flores
0.32
0.38
0.36
1.06
0.35 c
Kalbo-oy 0.76
0.82
0.58
2.16
0.72 a
Kuneing 0.59
0.66
0.72
1.97
0.66 ab
PSBSP 17
0.56
0.59
0.66
1.81
0.60 ab
TOTAL 3.69
3.99
3.96
11.64
3.88


ANALYSIS OF VARIANCE

DEGREES
TABULATED
SOURCE OF
SUM OF
MEAN
COMPUTED
OF
F
VARIANCE
SQUARES
SQUARE
F
FREEDOM
0.05 0.01
Replication 2
0.008
0.004
Treatment 6
0.372
0.062
10.54** 3.0 4.82
Error 12
0.071
0.006

Total 20
0.457


**–Highly significant
CV (%) =13.84


Evaluation of Sweetpotato Varieties for Leaf Tip Production
Grown Under Organic System / Daisy A. Abes. 2008

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Document Outline

• Evaluation of Sweetpotato Varieties for Leaf Tip Production Grown Under Organic System
  • BIBLIOGRAPHY
  • ABSTRACT
  • TABLE OF CONTENTS
  • INTRODUCTION
  • REVIEW OF LITERATURE
    • Varietal Evaluation
    • Importance of Variety Evaluation in Organic Farming
    • Nutritional Content of Sweetpotato Tops
    • Importance of Sweetpotato Tops
    • Importance of Chicken Manure
    • What is Organic Farming?
    • Use of Organic Fertilizers
  • MATERIALS AND METHODS
  • RESULTS AND DISCUSSION
    • Plant Survival
    • Plant Vigor
    • Reaction to Cutworm Infestation
    • Reaction to Leaf Scab Infection
    • Reaction to Stem Scab Infection
    • Average Number and Weight ofLeaf Tips of Sweetpotato
    • Sensory Evaluation/ Acceptabilityof Leaf Tips
    • Market Acceptability of Leaf Tips
    • Cost and Return Analysis
    • Soil Chemical Properties
  • SUMMARY, CONCLUSION AND RECOMMENDATION
    • Summary
    • Conclusion
    • Recommendation
  • LITERATURE CITED
  • APPENDICES

---