Cottonseed oil and yield assessment via economic heterosis and heritability in intraspecific cotton populations

Abstract

Due to the difficulty in producing cotton F₁ hybrid seed through hand emasculation and pollination, the capture of heterosis in cotton production is limited. The purpose of this study was to evaluate the potential of 6 × 6 F₁ and F₂ intra-hirsutum diallel hybrids relative to heterosis, inbreeding depression, heritability and correlation. Average F₁ hybrids mean values were higher than those of F₂ s, while F₂ s exceeded the parents. However, in F₁ s and F₂ s, the average mean values were 22.30 and 19.48 for seeds boll^-1, 8.87 and 8.56 g for seed index, 112.36 and 87.51 g for seedcotton yield and 30.07 and 28.30% for cottonseed oil. Heterosis over better parents was more pronounced in F₁ s as compared to F₂ s. However, in F₁ s and F₂ s, the average positive heterosis was 11.54 and 4.50%; 3.40 and 2.41%; 46.30 and 28.96% and 6.04 and 1.52%, respectively, for the above traits. Even after segregation and inbreeding depression, the F₂ s expressed about 50% of F₁ s heterosis. The inbreeding depression in F₂ s was -6.51 to -16.92 with low to high heritability, and significant positive correlation of cottonseed oil with other traits. The cultivar CIM-1100 derivatives performed better and exceeded all other hybrids in both generations.

Key words: Hybrid vigor, inbreeding depression, cottonseed traits, cottonseed oil, Gossypium hirsutum.