Impact of genotype x environment interaction on the heterosis and stability for seed-cotton yield on heterozygous and homozygous genotypes in cotton (Gossypium hirsutum L.)

Abstract

Heterozygosity and homozygosity in interaction with environment shows differential response in achieving yield stability. Widely diverse seven lines and nine testers of Gossypium hirsutum L. and their resultant crosses were assessed by observing twenty three characters using a line × tester system across three different locations to estimate comparative stability of heterozygous and homozygous genotypes for seed cotton yield plant–1. Comparisons were made using difference in heterobeltiosis, combining ability and stability parameters over environments and level of interaction with environment. An obvious increase in yield heterobeltiosis observed as environmental quality decreased indicating more stable nature of heterozygous hybrids aroused out of individual buffering than homozygous parents in low yielding environments. There was also a significant increase in SCA effects at low yielding environment. The stability parameters showed significant genotype x environment interaction. Genotype x environment interaction was linear for most of the characters indicating preponderance of linear component in these traits and hence prediction appeared possible. This stability was attributed to the hybrids out-yielding the homozygous parents in low yielding environment. Hence this research inferred the potential use of selected heterozygous hybrids which would allow to utilise more diverse environments or to mitigate losses during environmentally stressful years than homozygotes.