Diversity Heterosis and Combining Ability for Yield and Quality Traits and Genetics of Bacterial Wilt Resistance in Tomato Solanum lycopersicum L

Abstract

The present study was conducted to assess the amount of variability and newlinediversity present in the germplasm comprising of 60 genotypes of tomato using RCBD newlinedesign with three replications. The analysis of variance revealed significant genetic newlinedifferences among 60 tomato genotypes for all the studied traits. Based on variability, newlineassociation and path analysis we can conclude that, while choosing parents for newlinehybridization along with yield, other characters such as average fruit weight, number of newlineclusters per plant and number of fruits per plant are essential to be considered. With the newlinehelp of Mahalanobis D2 statistics, the genotypes were grouped into five clusters. The newlinecluster IV had the maximum number of genotypes (21). The maximum inter-cluster newlinedistance was observed between cluster II and IV. The genotypes PKM-1 and AVTO- newline1429 (12.17) exhibited maximum inter cluster distance distance. Screening was done in newlinesick plot against bacterial wilt resistance using 60 genotypes and six genotypes were newlinefound to be highly resistant and 23 genotypes were found to be resistant to bacterial newlinewilt. newlineHeterosis and combining ability analysis for yield and its component traits was newlinedone using 6 × 6 full diallel. Predominance of non-additive gene action was observed newlinefor all studied traits. For fruit yield per hectare, the cross STH-2031 recorded significant newlinestandard heterosis over three checks. To understand the nature and magnitude of gene newlineeffects of different yield related characters generation mean analysis was done. Using newlinetwo crosses DMT-2 × Line-38 and Line-33-1 × LA-1. Epistasis was confirmed by newlinescaling test and joint scaling tests for yield and yield components. Dominant and newlinedominant × dominant interaction was found for studied traits. In F2 population of both newlinecrosses, segregation ratio of 3 resistant: 1 susceptible was obtained indicating single newlinedominant gene governing the bacterial wilt resistance.