BIBLIOGRAPHY LABENIO, LENY ROSE LIBUATAN,...
BIBLIOGRAPHY
LABENIO, LENY ROSE LIBUATAN, MAY 2013. Varietal Screening of Potato
(
Solanum tuberosum) against late blight (
Phytophthora infestans) in Minac, Ballay,
Kabayan,Benguet. Benguet State University, La Trinidad, Benguet.
Adviser: Jocelyn C. Perez, MSc.
ABSTRACT
Eleven potato cultivars, two resistant check varieties and one susceptible variety
were evaluated at Minac, Ballay, Kabayan, Benguet.
The study aimed to screen cultivars for resistance to late blight during dry season
and to evaluate cultivars for yield and chipping qualities. Laboratory work was done at the
Plant Pathology Laboratory and at the Northern Philippines Roots Crops Research and
Training Center in Benguet State University (NPRCRTC-BSU).
Among the cultivars evaluated, MEVA, TPS-7 and Granola were observed to have
a fair or normal crop stand while other entries had plant vigor ranging from good and
vigorous to excellent and extra vigorous.
Based on the late blight infection ratings, varieties Granola and MS 35.9 were
observed to be the most susceptible to potato late blight and were categorized as moderately
susceptible to susceptible. Tubira, Baseko, TPS-7, Muziranzara, MEVA, Solibao, and
Igorota were classified as moderately resistant varieties whereas Precodepa and Gikungo
were highly resistant. The highest marketable yield was obtained from Gikungo while the
highest non-marketable was obtained from Muziranzara.
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
The lowest dry matter content was obtained from variety Tubira while
Muziranzara had the highest dry matter content.
In the sensory evaluation, chips from Solibao and Igorota varieties were liked very much
because chips were crunchy, and were moderately oily to oily.
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
RESULTS AND DISCUSSION
Plant vigor / Crop stand
The crop stand or plant vigor was evaluated 45 days after planting. Results
indicated that among the entries, Granola had a fair, normal crop stand which was not
significantly different from the crop stand of TPS-7 and MEVA. The cultivars
Muziranzara, Precodepa, MS 35.9 and Solibao were categorized as fair, normal to good
vigor which was not significantly different from the crop stand of Baseko, (Table 1).
Further, crop stand of Tubira, Igorota, and Gikungo were categorized as vigorous or good
vigor to excellent or extra vigorous were not significantly different.
Table 1. Plant vigor at 45days after planting
VARIETY/CLONES
MEAN
MS 35.9
2.7bc
Tubira
2cd
Baseko
2.3bcd
TPS-7
3ab
Gikungo
1.7d
MEVA
3ab
Muziranzara
2.7bc
Precodepa
2.7bc
Igorota
2cd
Solibao
2.7bc
Granola
3.7a
C.V. (%)
8.77%
Means with the same letter are not significantly different at 5% level of DMRT.
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Vigor is affected primarily by the inherent characteristics, secondly by the environment
including irrigation or moisture where the crop is grown (OSU, 1997).
Weekly Assessment of Late blight Infection
Recording of weekly late blight infection ratings was started 42 days after planting. In the
first assessment, (42 DAP), all the plants were infected with late blight but with minimal
spots except for MS 35.9, Precodepa and Granola which had more than ten spots per plant.
At the second week of infection ratings, most of the plant had 1% infection or about 10
spots per plant. Only the variety Granola and MS 35.9 had 25% infection or 50 spots of
blight.
Table 2. Mean weekly late blight infection and computed AUDPC
Days after
42
49
56
63
70
77
AUDPC
planting
1.00
5.00
11.00
33.33
98.33 100.00
1,387.12
MS 35.9
0.40
1.00
2.33
18.33
95.00 100.00
1,168.02
Tubira
0.40
1.00
1.00
18.33
98.33 100.00
1,182.02
Baseko
0.40
1.00
1.00
43.33
98.33 100.00
1,357.02
TPS-7
0.10
0.10
0.10
5.00
75.00 100.00
911.75
Gikungo
0.40
2.03
8.70
33.33
90.00 100.00
1,289.82
MEVA
0.40
1.00
1.00
5.00
58.33
98.33
802.87
Muziranzara
1.00
1.00
2.33
5.00
66.67 100.00
878.50
Precodepa
0.70
1.00
2.33
5.00
66.67
98.33
871.61
Igorota
0.70
1.00
0.70
11.67
75.00
98.33
965.20
Solibao
9.17
18.33
35.00
81.67
98.33 100.00
2,015.02
Granola
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
At 56, 63 until 70 DAP, the infection continued to increase as shown in Figure 3-13. This
was caused by the long rainy days which enhanced the multiplication of spores. Computed
of the Area under the Disease Progress Curve (AUDPC) showed that Granola had the
highest AUDPC at 2,015.02 and the lowest from Muziranzara (802.87), Igorota (871.61),
Precodepa (878.50), Gikungo (911.75) and Solibao (965.20).The higher the AUDPC, the
more susceptible the variety. In the last week of rating (77 DAP), almost all of the plants
were 100% infected by blight, where all of the leaves and stems were dead.
120
100
MS 35.9
Tubira
80
Baseko
TPS-7
Gikungo
60
MEVA
Muziranzara
Precodepa
40
Igorota
Solibao
Granola
20
0
42
49
56
63
70
77
Figure 2. Weekly assessment of Late blight Infection
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Varietal Reaction
At 30 DAP, most of the varieties were observed to be moderately resistant except
for the Gikungo and Precodepa which were rated as highly resistant. However, Granola
was observed to be moderately susceptible and MS 35.9 was susceptible, (Table 3).
Table 3. Varietal reaction of potato cultivars against late blight (
Phytophthora infestans)
TREATMENT
DESCRIPTION
% INFECTION
SCALE
MS 35.9
Susceptible
41-60%
3
Tubira
Moderately Resistant
20-40%
2
Baseko
Moderately Resistant
20-40%
2
TPS-7
Moderately Resistant
20-40%
2
Gikungo
Highly Resistant
1-20%
1
MEVA
Moderately Resistant
20-40%
2
Muziranzara
Moderately Resistant
20-40%
2
Precodepa
Highly Resistant
1-20%
1
Igorota
Moderately Resistant
20-40%
2
Solibao
Moderately Resistant
20-40%
2
Granola
Moderately Susceptible
61-80%
4
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Figure 3. Symptoms of late blight infection on clone MS 35.9 (56, 63, 70 DAP)
Figure 4. Symptoms of leaf blight infection on clone Tubira (56, 63, 70 DAP)
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Figure 5. Symptoms of leaf blight infection on clone Baseko (56, 63, 70 DAP)
Figure 6. Symptoms of leaf blight infection on clone TPS-7 (56, 63, 70 DAP)
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Figure 7. Symptoms of leaf blight infection on clone Gikungo (56 DAP)
Figure 8. Symptoms of leaf blight infection on clone MEVA (56, 63, 70 DAP)
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Figure 9. Symptoms of late blight infection on clone Muziranzara (56, 63, 70 DAP)
Figure 10. Symptoms of leaf blight infection on clone Precodepa (56, 63, 70 DAP)
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Figure 11. Symptoms of leaf blight infection on clone Igorota (56, 63, 70 DAP)
Figure 12. Symptoms of leaf blight infection on clone Solibao (56, 63, 70 DAP)
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Figure 13. Symptoms of leaf blight infection on clone Granola (56, 63, 70 DAP)
Yield Parameters of Marketable
According to Size, Non-marketable
There were significant differences on the weight of the marketable and non-marketable
tubers. The data revealed that there were more non-marketable tubers than the marketable
tubers, (Table 4& 5).The low marketable yield was due to the high mortality at an early
stage (77 DAP) which was due to early the infection of late blight which appeared at the
early tuber bulking stage affecting the size of harvested tubers. In addition, tubers were
infected by soilborne diseases like bacterial wilt and scab. In the extra large and small size
weight, only few of the potato had produced it. However, in terms of big size weight almost
all of the entries had produced it except for the Granola primarily because it was the first
one which was infected by the blight and it has the highest rating of blight. Late blight
remains a serious threat to potato production causing significant yield and economic losses
to farmers (Lungaho et. al, 1998). Gikungo and Igorota had the heaviest weight followed
by Precodepa, Solibao, Tubira, Baseko, TPS-7, MS 35.9 Muziranzara, MEVA and Granola
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
which had no yield. Moreover, in the non-marketable yield, the Muziranzara and Baseko
had the heaviest weight following Gikungo, MEVA, Igorota, Precodepa, Tubira MS 35.9,
Solibao, and TPS-7.
Table 4.Marketable yield tons per hectare
MARKETABLE YIELD
TREATMENT
tons/ha
Extra large
Big
Small
MS 35.9
0.00b
266.70c
53.33a
0.57cd
Tubira
0.00b
808.33bc
0.00a
1.50cd
Baseko
0.00b
700.00bc
26.70a
1.30cd
TPS-7
66.67b
350.00c
53.33a
0.84cd
Gikungo
133.33b
1,983.33a
120.00a
3.99a
MEVA
0.00b
156.70c
0.00a
0.27d
Muziranzara
0.00b
116.70c
150.00a
0.48cd
Precodepa
116.67b
950.00bc
170.00a
2.20bc
Igorota
353.33a
1,566.70ab
175.00a
3.74ab
Solibao
66.67b
416.70c
326.70a
1.43cd
Granola
0.00b
0.00c
0.00a
0.00d
CV (%)
8.53
10.99
97.73
17.42
Means with the same letter are not significantly different at 5% level of DMRT.
The highest computed yield in tons per hectare was obtained from Gikungo (3.99)
which was not significantly different from Igorota (3.74), and Precodepa (2.20). Whereas,
the lowest computed yield in tons per hectare was obtained from Tubira (1.50), Baseko
(1.30), Solibao (1.43), MS 35.9 (0.57), TPS-7 (0.84), MEVA (0.27), Muziranzara (0.48)
and Granola (0.00) which is significantly different.
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Table 5. Non-marketable yield
VARIETY/CLONES
MEAN
MS 35.9
1,343.30bcd
Tubira
1,608.30bc
Baseko
2,281.70b
TPS-7
800.00cd
Gikungo
2,200.00b
MEVA
1,666.70bc
Muziranzara
3,683.30a
Precodepa
1,633.30bc
Igorota
1,666.70bc
Solibao
1,183.30bcd
Granola
436.670d
CV (%)
5.11
Means with the same letter are not significantly different at 5% level of DMRT
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Non- marketable
Marketable
Figure 14.Marketable and non-marketable yield MS 35.9
Non-marketable
Marketable
Figure 15.Marketable and non-marketable yield of Tubira
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Non-marketable
Marketable
Figure 16.Marketable and non-marketable yield of Baseko
Non-marketable
Marketable
Fig ure 17. Marketable and non-marketable yield of TPS-7
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Non-marketable
Marketable
Figure 18. Marketable and non-marketable yield of Gikungo
Non-marketable
Marketable
Figure 19. Marketable and non-marketable yield of MEVA
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Non-marketable
Marketable
Figure 20.Marketable and non-marketable yield of Muziranzara
Non-marketable
Marketable
Figure 21. Marketable and non-marketable yield of Precodepa
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Non-marketable
Marketable
Figure 22. Marketable and non-marketable yield of Igorota
Non-marketable
Marketable
Figure 23. Marketable and non-marketable yield of Solibao
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Non-marketable
Figure 24. Marketable and non-marketable yield of Granola
Dry Matter Content
Tubira, Baseko and TPS-7 tubers had the lowest dry matter content at 14.67, 14.83,
and 15.83 respectively. This was comparable to Gikungo (16.17), MS 35.9 (17.17), Igorota
(17.17), MEVA (17.67) and Precodepa (17.83) while Solibao and Muziranzara had the
highest dry matter content at 20.00 and 18.50 which were significantly higher compared to
all the entries. This was followed by MEVA, Precodepa, and Solibao at 17.67 and 17.83,
(Table 6).
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Table 6. Dry matter content of potato tubers
VARIETY/CLONES
MEAN
MS 35.9
17.17cd
Tubira
14.67f
Baseko
14.83f
TPS-7
15.83f
Gikungo
16.17de
MEVA
17.67bc
Muziranzara
20.00a
Precodepa
17.83bc
Igorota
17.17cd
Solibao
18.50b
Granola
0.00g
CV (%)
0.79%
Means with the same letter are not significantly different at 5% level of DMRT
The low dry matter content is caused by excess of water during the growth of the plants
which results to low dry matter content, (Kellock, 1995). It is also affected by genetic
characteristics but probably influenced by water uptake, photoperiod, diseases and other
factors, (Rastovski, 2003). Further, Feltran (2004) found the same result that dry matter
content is influenced by the conditions in the site. The typical dry matter content for potato
chips is 21.7 to 25.1% (Fernando, 2010). The variety Igorota which was earlier reported
to the dry matter ranging from 20-21% had registered to very low dry matter content at
17.17% in this trial.
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Chipping Quality
Table 7 shows the results of the sensory evaluation of the potato chips from the different
entries. In terms of color, the chips fromMS 35.9, Baseko, Gikungo, MEVA, Muziranzara,
Igorota, and Solibao were liked very much. Chips from TPS-7 were liked moderately and
the chips from Tubira were liked slightly. Chips from Tubira were similar to cooked chips
which are infected with bacterial wilt. Color is the most important factor in the evaluation
for chipping. Hence, the yellow chips were the most preferred. Other skin color may be
selected as long as it will pass certain requirements of the processors (Sabiano, 2006).When
it comes to crunchiness or crispiness, all of the varieties were rated as crunchy except for
the TPS-7 which was moderately crunchy. MS 35.9, Tubira, TPS-7, Gikungo, MEVA,
Precodepa, and Igorota were rated as oily while Baseko, Miziranzara, and Solibao were
moderately oily. As to flavor, MS 35.9 and Igorota were liked very much while Tubira,
Baseko, TPS-7, Gikungo, Muziranzara, Precodepa, and Solibao were liked moderately by
the panelists whereas MEVA was liked slightly. Moreover, MS35.9, Tubira, Baseko, TPS-
7, Gikungo, MEVA, Muziranzara and Precodepa were rated as acceptable while Igorota
and Solibao were rated as highly acceptable.
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
Table 7.Sensory evaluation of potato for chipping quality
SENSORY CHARACTERISTICS
TREATMENT
COLOR
CRUNCHINESS
OILINESS
FLAVOR
GENERAL
ACCEPTABILITY
Like very
Like very
MS 35.9
Crunchy
Oily
Acceptable
much
much
Like
Like
Tubira
Crunchy
Oily
Acceptable
Slightly
moderately
Like very
Moderately
Like
Baseko
Crunchy
Acceptable
much
oily
moderately
Like
Moderately
Like
TPS-7
Oily
Acceptable
moderately
crunchy
moderately
Like very
Like
Gikungo
Crunchy
Oily
Acceptable
much
moderately
Like very
Like
MEVA
Crunchy
Oily
Acceptable
much
moderately
Like very
Moderately
Like
Muziranzara
Crunchy
Acceptable
much
oily
slightly
Like
Like
Precodepa
Crunchy
Oily
Acceptable
slightly
moderately
Like very
Like very
Highly
Igorota
Crunchy
Oily
much
much
acceptable
Like very
Moderately
Like
Highly
Solibao
Crunchy
much
oily
moderately
acceptable
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The field trial was conducted at Minac, Ballay, Kabayan, Benguet, and the laboratory
works was done at the Plant Pathology Laboratory and Northern Philippines Roots Crops
Research and Training Center Benguet-State University (NPRCRT- BSU) Area at La
Trinidad, Benguet from December 2012 to April 2013. The study aimed to screen
germplasm materials for resistance to late blight during the dry season and to evaluate
materials for yield and chipping qualities.
As to crop stand, Granola was observed to be fair or normal compared to the other cultivar.
Based on the late blight infection ratings, Granola and MS 35.9 were observed to be the
most susceptible to potato late blight as compared to Tubira, Baseko, TPS-7, MEVA,
Muziranzara, Solibao, Igorota, Solibao,Precodepa and Gikungo.Area under the Disease
Progress Curve (AUDPC) confirms the result because Granola and MS 35.9 has the highest
value at 2,015.02 and 1,387.12 compared to Muziranzara (802.87), Igorota (871.61),
Precodepa (878.50), and Gikungo (911.75) which had the lowest AUDPC. The higher the
value of AUDPC, the more susceptible the variety.
Granola and MS 35.9 were categorized as moderately susceptible and susceptible to late
blight. Tubira, Baseko, TPS-7, Muziranzara, MEVA, Solibao, and Igorota were classified
as moderately resistant whereas Precodepa and Gikungo were highly resistant. As to
marketable yield, the highest marketable computed yield in tons per hectare was obtained
from Gikungo and Igorota (3.99 and 3.74) while the highest non-marketable yield was
obtained from Muziranzara (3,683.3).
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
The lowest dry matter content was obtained from Tubira (14.67) while Muziranzara
tubers gave the highest dry matter content at 20.00.
In the sensory evaluation, chips from Solibao and Igorota were liked very much because
chips were crunchy, moderately oily to oily.
Conclusion
Among the cultivars evaluated, Gikungo exhibited the least late blight infection which was
descriptively resistant whereas the resistant checks Solibao and Igorota were rated as
moderately resistant. Computed Area under the Disease Progress Curve (AUDPC) value
was almost the same (Gikungo 911.75, Solibao 965.20, Igorota 871.61). Granola had the
highest infection rating which was described as moderately susceptible. In terms of yield,
dry matter and chip qualities, Gikungo, Muziranzara, Igorota and Solibao are the best.
Recommendation
Among the cultivars evaluated, Gikungo is recommended for dry season planting.
However, because of the low performance of the entries in this site compared to the good
perform in the other sites where the same entries were tested, it is further recommended
that the trial be repeated in the same municipality at the same planting season to validate
the results.
Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013
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Varietal Screening of Potato (Solanum tuberosum) against late blight (Phytophthora
infestans) in Minac, Ballay, Kabayan,Benguet |
LABENIO, LENY ROSE LIBUATAN, MAY 2013