Study on genetic variability in tomato
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Date
2011
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Publisher
CCSHAU
Abstract
The present investigation entitled “Study on genetic variability in tomato” was carried out at Research
Farm and Laboratories of the Department of Vegetable Science, CCS Haryana Agricultural University, Hisar
during spring summer season of the year 2010. The analysis of variance exhibited highly significant genotype
differences in the material indicating a wide range of variability existing for all the fruit yield and quality
characters investigated. The genotypic and phenotypic variances were observed high for fruit yield per plant
followed by plant height, average fruit weight, number of fruits per plant and fruit diameter. Similarly, both the
coefficients of variation were recorded highest for average fruit weight followed by fruit yield per plant, plant
height, number of fruits per truss, number of fruits per plant, fruit diameter and number of flower clusters per
plant, while of medium magnitude for rest of the characters and lowest for days to 50% flowering. In general, the
higher magnitude of phenotypic variances as well as coefficients of variation then the respective genotypic
estimates suggesting good influence of environment in the expression of the traits studied. The estimates of
heritability in broad sense ranged from 53.55% for days to 50% flowering to maximum high of 99.33% for plant
height followed by fruit diameter. And for all other characters these estimates were above 90%. The estimated
values of expected genetic advance for the characters studied followed the same pattern as that of components of
variance. These were recorded high for average fruit weight (124.56) followed by fruit yield per plant (101.16),
plant height (69.69), number of fruits per truss (68.94), number of fruits per plant (62.99), fruit diameter
equatorial and number of flower clusters per plant. While these estimates were in average range for fruit diameter
(polar), number of flowers per cluster, number of branches per plant, T.S.S., acidity and ascorbic acid. Hence
simple selection appeared effective for improvement of most of these traits. The plant height was observed
positively correlated with number of branches per plant, number of flowers per cluster, and number of fruits per
truss, and negatively with fruit diameter. The number of branches per plant in turn was found positively
associated with number of flowers per cluster, number of fruits per truss, whereas branches per plant exhibited
negative association with number of flower clusters per plant, fruit diameter and fruit yield per plant. Flowers
cluster per plant exhibited positive correlation with number of fruits per plant, while its relationship besides that
with the number of branches per plant, was also found negative with number of flowers per cluster, number of
fruits per truss and average fruit weight. Days to 50% flowering were found positively correlated with fruit
diameter average fruit weight and fruit yield per plant. The flowers per cluster beside its positive correlation with
plant height and branches per plant also expressed positive correlation with number of fruits per truss and
number of fruits per plant, while it had negative relationship with flower clusters per plant, fruit diameter and
average fruit weight. Number of fruits per truss also had the same trend of relationship as observed for flowers
per cluster. The fruit diameter recorded positive correlation with average fruit weight and fruit yield per plant
whereas it had negative significant correlation with number of fruits per plant, plant height, branches per plant,
flowers per cluster and fruits per truss. The average fruit weight was found positively correlated with fruit yield
per plant fruit diameter and days to 50% flowering and its relationship was in negative direction with number of
fruits per plant, flower clusters per plant, flowers per cluster and number of fruits per truss. The number of fruits
per plant showed positive association with flower clusters per plant, flowers per cluster and fruits per truss and
on the other hand negative association with fruit diameter and average fruit weight. The path coefficient analysis
depicted that average fruit weight followed by number of fruits per truss and flower clusters per plant contributed
maximum directly to yield. Plant height, flowers per cluster and fruits per plant via fruits per truss, days to
50% flowering; fruit size via average fruit weight; flower clusters per plant via branches per plant, and fruits per
truss via flowers per cluster contributed indirectly toward yield. Hence, these traits could be considered for
improvement in tomato through selection.
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Keywords
Fruits, Biological development, Storage, Mangoes, Plant growth substances, Calcium, Acidity, Sugar, Vitamins, Reducing sugars