Environmental Impact on the Combining Ability of Fiber Traits and Seed-Cotton Yield in Cotton

Abstract

Hybrids are widely accepted in all crops to improve yield, but genotype × environment interaction plays an important role in achieving high yield and superior quality traits. Three cytoplasmic genetic male sterile lines and seven testers of Gossypium hirsutum L. varying in seed cotton yield and fiber traits were assessed for hybrid vigor using a line × tester system across three different locations. The objectives of this study were to estimate 1) level of heterosis and specific combining ability (SCA) for fiber traits and seed‐cotton yield; 2) correlation between general combining ability (GCA) and line per se, as well as correlation between genetic distance and SCA; and 3) influence of environmental factors on combining ability estimates and trait correlations in parents and hybrids. The level of heterosis was acceptable for seed-cotton yield (32.46%) and fiber traits except uniformity ratio and fiber elongation. Combining-ability analysis across environments showed significant (P < 0.01) effects for genotypes, GCA, SCA, genotype × environment, GCA × environment, and SCA × environment interactions. Combining-ability variance revealed predominance of non-additive gene effects for seed-cotton yield, gin turnout, and micronaire, and additive gene effects for bundle strength and fiber elongation. A positive relationship was found between GCA effects and mean performance of parents, midparent value, and hybrid performance, with emphasis on the dominant gene effect for most of the traits studied. Positive correlation was found between GD and SCA effect. Environmental factors significantly affected the expression of fiber traits and seed‐cotton yield. The correlations among fiber traits and seed-cotton yield emphasized the possibility for improving both yield and fiber properties.