Gene Action Studies in the Inheritance of Yield and Quality Attributing Traits in Diallel Cross of Cotton (Gossypium hirsutum L.)

A field experiment was conducted to evaluate the 45 F1 hybrids derived from 10×10 half diallel fashion along with ten parents and one standard check GN.Cot.Hy-14 were sown in randomized block design with three replications during kharif -2017 at Cotton Research Station, Junagadh Agricultural University, Junagadh. The genetic components of variation were determined for 12 characters viz., days to 50% flowering, days to 50% boll opening, plant height (cm), number of monopodia per plant, number of sympodia per plant, number of bolls per plant, boll weight (g), seed cotton yield per plant (g), ginning percentage (%), seed index (g), lint index (g) and oil percentage (%).The estimate of the components of variation revealed significant results for both additive (D) as well as dominance effects (H1 and H2) for all the characters except plant height non-significant H2 component, but in majority of traits (except plant height, lint index) H1 was higher than D indicating dominance components were important in the inheritance of seed cotton yield and its components. The average degree of dominance (H1/D)1/2 was found to be more than unity for all the traits (except plant height, number of monopodia per plant and lint index indicating partial dominance) indicating over dominance. Asymmetrical distribution of positive and negative genes in the parents was observed for all the traits. High estimates of heritability in narrow sense was observed for days to 50% flowering, days to 50 % boll bursting, number of monopodia per plant, ginning percentage (%), lint index (g) and oil content (%) suggesting that selection based on these attribute would lead to rapid improvement. Due to preponderance of non-additive gene effects of seed cotton yield per plant and most of its component traits, heterosis breeding would also be practically feasible in cotton.