Heterosis, Inbreeding Depression and Transgressive Segregation for Seed Yield and Component Traits in Sesame (Sesamum indicum L.)

Abstract:

Sesame is an essential oilseed crop highly valued for high-quality edible oils. However, sesame has low yields, a lack of genetic variability and is susceptible to many biotic and abiotic stresses which hinder improvements in yield. The current study was performed to estimate heterosis, inbreeding depression and transgressive segregation of seed yield and its component traits in sesame, using a half-diallel mating scheme. The study involves twelve genetically diverse sesame genotypes crossed in half-diallel fashion to generate 66 F₁ and 66 F₂ hybrids. The experiment was laid in a randomized complete block design at Junagadh Agricultural University, India. The analysis of variance (ANOVA) indicated highly significant differences (P<0.01) between the genotypes for all the studied traits, indicating a substantial amount of genetic variability. The results reported significant amounts of heterosis, hybrid vigor as well as multiple traits associated with seed yield and seed yield components. The crosses AT-591 × G. TIL-10, AT-591 × G. TIL-11, G. TIL-10 × G. TIL-11 displayed significant high levels of standard heterosis for seed yield per plant and desirably exhibited positive heterosis for many of the attributes that contribute to seed yield. Moreover, the moderate to great amount of inbreeding depression exhibited for many traits suggested the presence of greater amounts of non-additive gene action within each of the parental genotypes. The crosses AT-556 × AT-591, AT-582 × G.TIL-11, AT-591 × G.TIL-10 and G.TIL-10 × G.TIL-11 can be considered as the most promising combinations for isolating superior transgressive segregants and obtaining high yielding pure lines in sesame.