Gene action studies for quantitative trait of tomato in Kashmir condition

The primary objective of the present investigation was to better understand the type of gene action in tomato for diverse quantitative traits. Fourteen diverse lines of tomato were crossed in half diallel fashion and the F1’s were evaluated in two environments (E1 and E2) at SKUAST-K, Srinagar. The analysis of variance for all the fourteen quantitative traits revealed significant mean squares in both E1 and E2. The dominance variance was found higher than the additive variance for most of the traits. The gene action studies revealed greater magnitude of dominance component than its corresponding additive component indicated major role of the former in the inheritance of those traits. The net dominance effect component (h2) revealed absence of high dominance effect in heterozygote and absence of directional dominance for all such traits. However, for DuF, PH and NLPF in both E1 and E2, high dominance effect in heterozygote and presence of directional dominance was observed. The F value indicated higher frequency of dominant alleles in the parents for traits viz., DFFS, DuF, PH, FlPT, FrPT and NFPP and equal frequency of dominant and recessive alleles in DFFR, DuM, AFW, FS, FYPP, NLPF, PT and NSPF in both E1 and E2. The [(H1/D)1/2] revealed over dominance range for all the traits under study in both E1 and E2. The H2/4H1 indicated the asymmetrical distribution of alleles with positive and negative effect in the parents for all the traits. KD/KR revealed excess of dominant genes in parents as compared to the recessive genes. The h2/H2 depicted the less proportion of dominance gene groups and probably one gene group control these traits. The low narrow sense heritability [h2 (n.s.)] revealed non-additive gene action for most of the traits except FYPP in both E1 and E2. The study highlights the importance of both additive and non-additive gene action involved in the inheritance of different growth, yield and quality traits.