GENETIC DIVERGENCE AND SCREENING TOMATO (Solanum lycopersicum L.) GERMPLASM FOR YIELD, QUALITY AND RESISTANCE AGAINST ROOT-KNOT NEMATODE (Meloidogyne incognita)
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Date
2018-07-30
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College of Horticulture, Rajendranagar, HYD-30
Abstract
The present investigation entitled “Genetic divergence and screening
tomato (Solanum lycopersicum L.) germplasm for yield, quality and
resistance against root-knot nematode (Meloidogyne incognita)” was
undertaken to estimate the genetic divergence, yield component analysis through
correlation and path analysis and screening against root-knot nematode
(Meloidogyne incognita). Thirty one genotypes were evaluated in a Randomized
Block Design with three replications during rabi, 2017-2018 at College of
Horticulture, Rajendranagar, Hyderabad.
The analysis of variance (ANOVA) of RBD revealed highly significant
differences among the genotypes for all the fourteen characters. Wide range of
variability was observed for average fruit weight (4305.12) followed by plant
height (2772.80) and number of fruits per plant (1024.360) indicating the scope
for selection of initial breeding material for further improvement.
The result of mean performance of thirty one genotypes for fourteen
characters revealed that the genotype EC-620378 was the superior for yield and
yield contributing characters i.e. fruit yield per plant (2.44 kg) and yield per plot
(34.10 kg). The genotype EC-917090 was found to be early as observed from the
character days to first flowering (27.00 days) and days to 50% flowering (30.50
days).The genotype EC-163605 was found superior to number of clusters per
plant (36.33).The genotype EC-165700 was found superior to days to first fruit
set (61.33). The genotype EC-914109 was found superior to days to first fruit
harvest (36.33). The genotype EC-249504 was significantly superior for plant
height (185.00 cm). The genotype EC-164334 was significantly superior to
number of branches (20.8). The genotype EC-917090 was significantly superior
for number of fruits per plant (98.66), ascorbic acid (42.56mg/100gm) and
lycopene (6.24mg/100g). The accession EC-631364 was found to be superior for
TSS (5.62 0Brix). The check variety Laxmi was found to be superior for lycopene
content (4.95mg/100gm) followed by Marutham (4.82mg/100gm).
Mahalanobis D2 statistical analysis revealed that number of fruits per plant
contributed maximum towards divergence followed by ascorbic acid, yield per
plot, number of clusters per plant, plant height, lycopene content, average fruit
weight and TSS. The D2 analysis for fourteen characters partitioned the thirty one
genotypes into six clusters. The inter cluster D2 values of the six clusters revealed
that highest inter cluster generalized distance (819.88) was between cluster I and
VI, while the lowest (171.10) was between cluster II and cluster III. The clusters
showing high genetic divergence could be effectively utilized in heterosis
breeding programme.
High heritability coupled with high genetic advance as per cent of mean
indicates operation of additive gene action this was observed in characters viz.,
20
plant height, number of branches per plant, number of clusters per plant, number
of fruits per plant, average fruit weight, fruit yield per plant, yield per plot,
ascorbic acid content, TSS, and lycopene content. The high genetic variability
was observed for the characters viz., plant height, number of branches, number of
fruits per plant, average fruit weight, fruit yield per plant, yield per plot and
ascorbic acid, which indicates the significance so, that these characters can be
used for selecting superior genotypes.
From correlation studies, fruit yield per plant exhibited high significant
positive association with average fruit weight, number of fruits per plant, fruit
yield per plot, lycopene indicating the importance of these traits in selection for
yield. Direct selection based on these traits would result in simultaneous
improvement of afore said traits and yield per se in tomato.
The path coefficient analysis in the study revealed the improvement of
yield by improving the characters i.e days to first flower, fruits per plant and
average fruit weight. Yield per plant of tomato can also increased indirectly
through number of plant height, days to fruit set, number of fruits per plant and
average weight of fruit.
Thirty one genotypes were screened for their reaction to root-knot
nematode (Meloidogyne incognita). None of the genotypes were found resistant.
The cultivar Hisar Lalit found moderately resistant. Two genotypes (EC-631364
and EC-620395) were found susceptible while the remaining 28 genotypes were
found highly susceptible root-knot nematode.
Considering the mean performance, eleven superior genotypes viz., EC-
620378 (2.44kg), EC-917090 (2.01kg), EC-631356 (1.92kg), EC-914109
(1.87kg), EC-62389 (1.85kg), EC-164334 (1.66kg), EC-914099 (1.64kg), EC-
620395 (1.60kg), EC-249514 (1.56kg), EC-914089 (1.46kg), and EC-538156
(1.42kg) were superior for yield per plant which may be released as pureline
varieties after testing their stability over locations and years for commercial
cultivation. The genotypes with superior quality traits viz., EC-917090 for
ascorbic acid (42.56mg/100gm) and lycopene (6.24mg/100g) and EC-631364 for
TSS (5.62 0Brix) and can be included in pedigree selections for further
improvement.
Description
The analysis of variance (ANOVA) of RBD revealed highly significant
differences among the genotypes for all the fourteen characters. Wide range of
variability was observed for average fruit weight (4305.12) followed by plant
height (2772.80) and number of fruits per plant (1024.360) indicating the scope
for selection of initial breeding material for further improvement.
Keywords
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Citation
Sri Konda Laxman Telangana State Horticultural University, Rajendranagar, Hyderabad-30