Heterosis and inbreeding depression studies for Seedcotton yield and its components in upland cotton (Gossypium hirsutum L.)

Six generation (P1, P2, F1, F2, BC1 and BC2) of four crosses viz., cross I (MCB-16-1×GTHV 0/32), cross II (MCB-16-1×GTHV-17/70), cross III (GTHV-17/15×GTHV-0/35) and cross IV (MCB-9-2×GSHV-204) derived from eight genotypes and they were evaluated to study heterosis and inbreeding depression for seed cotton yield and its component traits. Out of that, for seed cotton yield and its component traits, cross IV (MCB-9-2 × GSHV-204) registered the highest estimate of relative heterosisalong with significant and desired inbreeding depression.The crosses MCB-16-1 × GTHV-17/70 and GTHV-17/15 × GTHV-0/35 demonstrated significant positive heterobeltiosis for key economic traits such as seed index, lint index and ginning outturn. Additionally, these hybrids exhibited notable inbreeding depression for traits like plant height, number of sympodia and fiber strength, indicating the involvement of non-additive gene action. The findings of the present study suggest promising opportunities for both the isolation of superior pure lines from heterotic F2 populations and the commercial exploitation of heterosis in cotton breeding programs.