GENETIC VARIABILITY, HETEROSIS AND COMBINING ABILITY STUDIES FOR YIELD AND QUALITY TRAITS IN TOMATO (Solanum lycopersicum L.)
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Date
2018-07
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UNIVERSITY OF HORTICULTURAL SCIENCES, BAGALKOT (COLLEGE OF HORTICULTURE, Bengaluru).
Abstract
Investigations were conducted to assess the “Genetic variability, heterosis and combining ability for yield and quality traits in tomato (Solanum lycopersicum L.)” between 2015-2017 at College of Horticulture, Bengaluru. Two hundred genotypes collected from different institutes were evaluated for genetic variability. Significant differences were observed among the genotypes for all the characters studied. The estimates of GCV and PCV were moderate to high for all 13 characters. High heritability with high GAM was recorded for most of the growth, yield and quality characters indicating the predominance of additive gene components in governing these traits. Genetic divergence studies categorised these 200 genotypes into 80 distinct clusters. The cluster-II showed maximum intra cluster diversity (D2=2965.87) followed by cluster-I (D2=2384.00). Inter cluster distance revealed the maximum divergence between clusters-VII and cluster-VIII (D2=37547.80) followed by between Cluster-V and cluster-VIII (D2=25781.20). The characters like number of fruits per plant (54.76%), plant height (25.62%) and average fruit weight (18.26%) contributed maximum towards expression of genetic divergence. Fruit yield per plant had a positive and highly significant association with number of branches per plant, fruit width, pericarp thickness, number of fruits per plant, average fruit weight0and firmness indicating the possibility of simultaneous improvement of these traits in improving fruit yield per plant. Analysis of variance for general combining ability and specific combining ability revealed the predominance of both additive and non-additive gene action for the characters under the study. Parents viz., ARTD-6, EC-620446, IIHR-2195, IIHR-2199, Punjab Ratta and Kashi Sharad were good general combiners (GCA) for yield per plant and quality parameters. The maximum specific combining ability (SCA) effects was observed in the crosses viz., IIHR-2199 x PTR-6, ARTD-6 x Punjab Ratta, EC-620446 x Punjab Ratta for yield per plant, number of fruits per plant, average fruit weight and fruit quality traits like pericarp thickness, TSS and firmness. Sixty six hybrids were developed by using eleven lines and six testers. The crosses, EC-620446 x Punjab Ratta followed by ARTD-6 x Punjab Ratta, H-86 x Kashi Sharad, IIHR-2199 x PTR-6, EC-620446 x Kashi Sharad, ARTD-6 x Kashi Sharad and IIHR-2195 x Kashi Sharad expressed significant heterosis over commercial check (Abhilash) for economic characters like yield and its attributing traits.