Genetic evaluation of yield and fibre quality traits in Bt cotton (Gossypium hirsutum L.) using line × tester mating design

Abstract

The present study was carried out at the Cotton Research Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, to assess heterosis and combining ability for yield and fibre quality traits in Bt cotton. A total of 10 F1 hybrids, developed through a line × tester mating design involving two female lines and five male testers during kharif 2023, were evaluated along with 7 parents and four standard checks in a randomized block design with two replications during kharif 2024. Significant variation was observed among genotypes for all traits studied, indicating substantial genetic diversity. Among the hybrids, AKBt-6 X AKBt-206 exhibited the highest standard heterosis for seed cotton yield over the best check (Rasi Swift). In terms of fibre quality traits, here also AKBt-6 X AKBt-206 showed superior performance for upper half mean length and fibre strength. AKBt-96 X AKBt-14 demonstrated the most desirable negative heterosis for fibre fineness. General combining ability (GCA) analysis revealed AKBt-6 as strong general combiner among female for yield and quality traits, while AKBt-206 showed favorable GCA effects for most of the yield and fibre quality traits. Specific combining ability (SCA) analysis identified AKBt-96 X AKBt-14, AKBt-6 X AKBt-212 and AKBt-6 X AKBt-206 as promising crosses for yield and fibre attributes. These findings provide valuable insights for selecting superior hybrids and parents for cotton improvement programms.