Assessment of Combining Ability and Gene Action for Seed Cotton Yield and Fibre Quality in Inter and Intra Specific Cotton Hybrids

Abstract

The present research study was undertaken to assess combining ability, gene action and heterosis for seed cotton yield, yield-attributing traits and fibre quality parameters in inter- and intra-specific cotton hybrids involving Gossypium hirsutum L. and Gossypium barbadense L. Six cotton genotypes comprising four G. hirsutum lines (Adilabad kapas-1, ADB-39, ARBC-64 and CNH-115) and two G. barbadense lines (Suvin and Phule Rukhmai) were crossed in a half-diallel fashion to generate fifteen single-cross hybrids, which along with their parents were evaluated in a randomized block design with two replications at the Agricultural Research Station, Adilabad, Telangana, during Kharif 2020–2021. Observations were recorded on seed cotton yield, yield components and fibre quality traits, and combining ability analysis was performed using Griffing’s Method II, Model I, along with estimation of genetic parameters such as heritability, degree of dominance and genetic advance. Analysis of variance revealed significant differences among parents and hybrids for most traits, indicating substantial genetic variability, with both general combining ability (GCA) and specific combining ability (SCA) variances being significant for the majority of characters. Non-additive gene action predominated for most yield and fibre quality traits, whereas additive gene action was observed for days to 50 per cent flowering and ginning out-turn. The parents ADB-39 and CNH-115 were identified as good general combiners for seed cotton yield, while Suvin and Phule Rukhmai were superior general combiners for fibre quality traits, and the crosses Adilabad kapas-1 × Phule Rukhmai, ADB-39 × Phule Rukhmai and Suvin × ARBC-64 exhibited significant positive SCA effects for seed cotton yield, indicating greater scope for heterosis breeding and effective utilization of these parents and hybrids in developing high-yielding cotton cultivars with improved fibre quality.