Cotton is a valuable industrial fiber crop grown in many regions worldwide. Four cotton (Gossypium hirsutum L.) cultivars, i.e., Ishonch, Navbakhor-2, C-6524, and Tashkent-6, and their F_1-2 diallel hybrids’ cultivation comprised a randomized complete block design with a factorial arrangement and four replications during 2019–2021 in the Tashkent Region, Uzbekistan. Significant (P ≤ 0.01) differences were notable among the parental genotypes and their F₁ hybrids for boll weight and seed cotton yield. The parental cultivars Ishonch and Navbakhor-2 and their F₁ diallel hybrids showed more stability and performed better than other genotypes. Broad-sense heritability estimates were the highest for boll weight and seed cotton yield while lowest for bolls per plant. Based on this trait’s yield, heritability, and variability, the inbreeding depression was positive in the F₂ populations Ishonch × Navbakhor-2 and Navbakhor-2 × Tashkent-6. According to yield, the cultivars Ishonch, Navbakhor-2, and Tashkent-6 were outstanding as positive donors.

Keywords: Cotton (G. hirsutum L.), genetic variability, heritability, genetic gain, correlation coefficient, heterosis, inbreeding depression

Key findings: Cotton (G. hirsutum L.) cultivars Ishonch, Navbakhor-2, Tashkent-6, and their F₁ diallel hybrids performed better for bolls per plant, boll weight, and seed cotton yield per plant.