Manifestation of heterosis in interbreed crosses of high, medium, low and control lines selected for pupal weight in silkworm is reported. Significant positive heterosis over better parent in the selected and correlated traits was obtained due to the wider genetic distance noticed in Pure Mysore (multivoltine) and NBtS (Bivoltine). Whereas, the magnitude of heterosis varied among interbreed crosses which involved all three types of gene effects (additive, dominance and epistatic interactions). The present study indicated that heterosis was more pronounced in the crosses involving bivoltine which happen to be either low male or female component and is dearly demonstrated in the heterosis averaged over male and female parents. Higher pupal weight does not necessarily result in higher heterotic values so, while selecting the parents for commercial exploitation differential pupal weight should also need to be considered.
Mulberry silkworm, pupal weight, selection, heterosis
