Genetic effects of combining ability studies for quantitative traits in intraand interspecific crosses of diploid cotton (G. arboreum and G. herbaceum)

Forty-five intra-and interspecific diploid or desi cotton hybrids (G. arboreum x G. herbaceum) derived from half diallel mating design, by involving ten diverse parents of G. herbaceum and G. arboreum were evaluated to study combining ability for seed cotton yield and its component traits. Mean squares due to GCA and SCA variance were highly significant for all the 11 agro-morphological characters studied. The variance due to GCA and SCA for mean squares was highly significant, which suggested that additive and non-additive gene action is involved for controlling all the characters. Combining ability analysis suggested the preponderance of non-additive type of gene action for all the traits except days to 50% flowering and no. of monopodia per plant. Based on per se performance, parent GAM-165 and cross GBhv-282 x G27 was superior for seed cotton yield and lint yield per plant. The parent G-27 and GBhv-287 was found to be the best general combiner for majority of the traits. Based on sca effects, GBhv-282 x G 27 exhibited significant sca effects for seed cotton yield per plant, lint yield per plant, number of bolls per plant, boll weight and no. of sympodia per plant. Heterosis breeding will be useful for diploid cotton improvement due to presence of non-additive type of gene action.