Combining ability and heterosis studies for seed cotton yield and fibre quality traits in hirsutum cotton

To study the combining ability, gene action and heterosis, eighteen intra-hirsutum cotton hybrids were developed by crossing three lines (females) and six testers (mlaes) in line × tester design during Kharif 2021 at Regional Agricultural Research Station, ANGRAU, Lam, Guntur. The analysis of variance revealed significant variability among the experimental material for seed cotton yield, lint yield, and fibre quality traits. The non-additive gene action was observed for traits namely, ginning out turn, seed cotton yield, lint yield, and fibre quality traits while the upper half mean length and uniformity index exhibited preponderance of additive gene action. Among the parents, TCH 1837 (Line) and Lam GPC 274 (Tester) were identified as the best general combiners for the traits, bundle strength and elongation while the lines, SCS 1207, GISV 298, and tester Lam GPC 235 were identified as the best combiner for ginning out turn, seed cotton yield, and lint yield. The F1 hybrids viz., TCH 1837 / Lam GPC 117, GISV 298 / Lam GPC 274, and GISV 298 / Lam GPC 51 were identified as the best hybrids and these could be used for exploitation through heterosis breeding as these hybrids exhibited significant per se performance, high positive SCA effects and better parental heterosis for the said characters. The cross combinations namely, GISV 298 / Lam GPC 235 and SCS 1207 / Lam GPC 355 possessed significantly high GCA effects for the parents and non-significant SCA effects for the corresponding hybrids for important yield components and fibre quality traits. Hence, these could be exploited in recombination breeding for improvement of yield and other fibre quality traits in cotton.