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.