Assessment of combining ability and gene action for seed cotton yield and fibre quality traits in Lintless-Fuzzless genotypes of upland cotton (Gossypium hirsutum. L)

Background: Knowledge of genetic diversity is the prerequisite to choose the parents for heterosis breeding aimed at the improvement of any trait in cotton as hybridization among the accessions belonging to diverse genetic background exhibited desirable recombinants in segregating generation. Understanding the genetic behaviour of lint and fuzz formation in cotton is crucial for improving cotton production and developing new cotton varieties with desired traits. Result The current study was intended to evaluate the genetic diversity among different fuzzy and fuzzless genotypes and to understand the gene action and combining ability of seed cotton yield and yield contributing characters along with fibre quality. Principal component analysis revealed that the first four principal component analyses (PCs) out of the total eleven PCs exhibited higher eigen values (> 1) and had maximum contribution to total variability (89.46%). The attributes that had maximum share to total divergence included number of bolls per plant, number of sympodia, ginning out turn, elongation percentage, uniformity index, fibre length, fibre strength, days to first boll opening and days to fifty percent flowering. Line x Tester mating design was used to develop 36 hybrids. Study of biometrical traits revealed that the dominance variance was higher than the additive variance in both the sets. Considering the per se performance and gca effects, CO 14 and CO17 were found to be elite general combiners for yield and fibre quality traits which can be further utilized as parents in breeding programme. The hybrids with high sca effects in the desired direction were TCH1646 / CO17 and MCU5 / AKH9881 which showed best performance for yield and yield contributing traits. Conclusion It is quite important to breed new genotypes that have no fuzz on the seed and higher gin turnout. Fuzzless but fibery genotypes might be utilized to reach this goal. Seed cotton yield and its contributing characters were controlled non additively and hence hybrid breeding is the best choice for crop improvement.