Genetic architecture of some yield and biochemical traits of tomato Solanum lycopersicum L

The present study was carried out to determine fruit yield related traits by crossing 8 diverse tomato lines/varieties in partial diallel manner. Eight parents, 28 F₁ and 28 F₂ were evaluated in RBD with three replications. Analysis of variance showed that genotypes and both generations differed significantly among each other for all the traits studied. The estimate of component of genetic variation revealed that additive components (D) of variance, dominant genetic variance (H1 and H2) and dominance effect were found significant for plant height and fruits plant-1 in both generations. The estimates and dominance component (H)were greater than additive component(D) of variance indicating preponderance of dominant gene action for the expression of all the characters under the study. The ratio of dominant and recessive gene(KD/KR) in the parents showed their asymmetric distribution among the arrays. The H2/4H1 ratio showed an excess of dominant alleles among the patents and dominance was unidirectional in both F₁ and F₂ generations. Environment factor E significantly influenced harvest span. The estimates of mean degree of dominance revealed over dominance for all the characters in both generations. All the characters except fruit yield in F₁ were appeared to be controlled by at least one gene group. High heritability estimates were noticed for fruit acidity content in F₁ generation suggesting preponderance of additive gene effects. Low to high heritability estimates in narrow sense were observed for all the traits, controlled predominantly by dominant genes. Fruit yield showed low heritability (7.52 in F₁ and 8.19 in F₂ generation)indicated non additive gene action suggesting exploitation of heterosis breeding in F₁ and selection of desirable segregants infurthergenerations.