Heterosis and inbreeding depression in racial derivatives of Gossypium hirsutum L. for bollworm (Helicoverpa armigera Hubner) resistance

Heterosis over mid parent and better parent in F₁ and inbreeding depression in the F₂s were studied for number of sympodia per plant, number of bolls per plant, seed cotton yield per plant, ginning outturn, boll damage and locule damage. The relative heterosis and heterobeltiosis were significant for seed cotton yield in all the six crosses. The relative heterosis was negatively significant for boll damage and locule damage confirming bollworm damage in the F₁, but compared to the better parent the bollworm damage was high in F₁. The inbreeding depression was positive for boll damage and locule damage in all the six crosses showing less bollworm damage in F₂ generation and it will be because of the segregation of resistant genes.