In intraspecific F₁ diallel hybrids of Gossypium barbadense L., the inheritance study of traits plant height, boll weight, plant productivity, and 1000-seed weight, with combining ability analysis took place in 2020–2022 at the Institute of Genetics and Plant Experimental Biology, Academy of Sciences, Uzbekistan. These polygenic traits’ inheritance showed different ways in the fine-fiber cotton F₁ hybrids. The plant height trait’s inheritance with overdominance and intermediate level of the high/low-performance cultivars. The boll weight trait was mainly in negative overdominance with incomplete dominance of the low-performance cultivar. The inheritance of seed cotton yield had the positive overdominance main control, while the 1000-seed weight had negative and positive overdominance. According to combining ability analysis, the highest positive general combining ability effects resulted in fine-fiber cotton cultivars Surkhan-14 (ĝi = 8.71) and Bo’ston (ĝi =1.86) for plant height, Guzor (ĝi = 0.12) for boll weight, in genotypes Marvarid (ĝi = 2.44) and Surkhan-14 (ĝi = 2.95) for plant productivity, and in cultivars Marvarid (ĝi = 2.3) and Guzor (ĝi = 2.8) for 1000-seed weight. The F₁ hybrids Guzor × Surkhan-14, Marvarid × Bo’ston, and Bo’ston × Surkhan-14 showed the highest positive and desirable specific combining ability effects for 1000-seed weight and seed cotton yield. Results concluded that fine-fiber cotton cultivars Marvarid, Surkhan-14, and Guzor can benefit as initial breeding material in selecting high-yielding cotton cultivars.

Keywords: G. barbadense L., cotton cultivars, F₁ diallel hybrids, inheritance, heterosis, combining ability, yield traits, cotton productivity

Key findings: Results authenticated that it is feasible to use fine-fiber cotton cultivars Marvarid, Surkhan-14, and Guzor as initial genetic material in selecting high-yielding cotton cultivars.