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