Assessment of genetic diversity in Tomato (Solanum lycopersicum L.)
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Date
2016-05
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Vegetable Science Dept., ACHF, NAU, navsari
Abstract
Assessment of genetic diversity was studied in set of twenty-five genotypes of tomato (Solanum lycopersicum L.) grown in a randomized block design with three replications during rabi 2014-15 at Regional Horticultural Research Station, NAU, Navsari. Analysis of variance revealed significant genotypic differences for all the fifteen characters indicated a wide range of variation was apparent for all the characters. The genotypic and phenotypic coefficient of variation, heritability and genetic advance were observed higher for number of branches plant-1 at final harvest followed by plant height at final harvest (cm), pericarp thickness (mm), ascorbic acid content (mg 100g-1), lycopene content (mg 100g-1), fruit yield plant-1 (kg), average fruits weight (g) and number of fruits plant-1 indicating that phenotypic selection would be effective for genetic improvement in these traits.
Association between fruit yield and other contributing characters revealed that fruit yield plant-1 had highly significant and positive correlation with number of fruits plant-1, average fruit weight (g) and lycopene content (mg 100g-1) at genotypic and phenotypic levels. The number of fruits plant-1 had highly significant and negative correlation with average fruit weight (g) at both genotypic and phenotypic levels indicated that increased in one trait decreased the other and vice-versa.
Path coefficient analysis indicated that number of fruits plant-1 having highest positive direct effect on fruit yield plant-1 (kg) followed by average fruit weight (g). Based on these findings, it can be suggested that for improving fruit yield in tomato, more emphasis should be given to days to 50% flowering, plant height, number of fruits per pant, number of branches per plant and average fruit weight.
Genetic divergence was carried out using Mahalanobis's D2 statistic for twenty-five tomato genotypes were grouped in seven clusters. The clustering pattern of the genotypes was independent of their geographical distribution. On the basis of inter cluster distances, cluster V was found to be more divergent with cluster VI and VII. Therefore, it was concluded that the genotypes belonging to these clusters should be inter-crossed in order to generate more diversity and improving fruit yield in tomato. In the present study, pericarp thickness contributed maximum towards the divergence followed by ascorbic acid, lycopene content, total sugar, fruit yield plant-1, TSS and plant height at final harvest.
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