GENETIC ANALYSIS AND HETEROTIC STUDIES IN TOMATO (SOLANUM LYCOPERSICUM L.) HYBRIDS FOR FRUIT YIELD AND ITS RELATED TRAITS

Abstract

A study was conducted to determine the types of gene action of different yield-related traits in tomato and the combining ability in four advanced lines. The heterotic response in tomato hybrids was also assessed. Analysis of variance (ANOVA) revealed significant differences (P ≤ 0.05) among all the traits. General combining ability (GCA) and specific combining ability (SCA) for all chosen traits were computed using Griffing’s approach of diallel. Combining ability revealed the additive and non-additive genetic effects for all selected traits of advanced lines. T-1360 was found as a good general combiner for the number of cluster plant-1, average fruit weight, number of flowers cluster-1, fruit length, number of fruit cluster-1, and yield. The variance of the GCA to SCA ratio was found less than 0.5 for each trait, which confirmed the presence of non-additive gene action. The results revealed higher magnitudes of phenotypic coefficient of variance (PCV) than the genotypic coefficient of variance (GCV). The high magnitudes of heritability (72% to 92%) and genetic advance (36.63% to 139.72%) were found for the number of cluster plant-1, average fruit weight (g), the number of fruits cluster-1, and yield. Among all crosses, the cross ST-100 × T-1360 showed maximum positive heterosis over the mid parent (566.6%) and the better parent (455.5%). The identified tomato genotypes can be used further in different tomato breeding programs to improve fruit yield and other yield-related traits.