Genetic analysis in different cotton (Gossypium hirsutum L.) hybrid populations and generations

Objective: It was aimed to determine the intergenerational and intra-generational performance of hybrid cotton combinations, inbreeding depression, standard heterosis and broad sense heritability. Materials and Methods: F3 seeds of 13 double cross populations constituted the initial material of the study. In 2022, the F3 and F4 populations and in 2023, the F4 and F5 populations were evaluated according to the Randomized Complete Block Design with 3 replications. Results: Significant genotypic differences were found in F3/F4 and F4/F5 generations for boll number, boll weight, single plant seed cotton yield, ginning out-turn, fiber length, fiber fineness and fiber strength. In both years, inbreeding depression was generally favorable positive for single plant yield, boll number, boll weight, earliness traits and hundred seed weight, but generally unfavorable for plant height, ginning out-turn and fiber quality traits. Broad sense heritability was moderate for boll number, boll weight, single plant seed cotton yield and hundred seed weight, but high for ginning out-turn and fiber quality traits. When compared with the check cultivar May-455, F5 populations exhibited negative standard heterosis for single plant yield, boll number, boll weight, number of sympodial branches, ginning out-turn, but positive standard heterosis for fiber length and fineness. Conclusion: It was concluded that Julia / ST-468 // Carmen / Carisma, Carisma / Carmen // Gloria / Carisma, Julia / ST-468 // Gloria / Flash) and ST-468 / Claudia // Gloria /Flash F5 hybrid combinations should be transferred to the next generations for high yield, ginning yield above 40%, fiber fineness, fiber strength and fiber length within commercial limits. Keywords: Bulk, heterosis, inbreeding depression, heritability, yield