author(s)
Kritika Sharma and Kamlesh Bali

abstract
The investigation was carried out during spring 2018, to rear six parents and thirty-one hybrid combinations including control by involving full diallel set of bivoltine breeds in a complete randomized design (CRD) to identify the high yielding bivoltine silkworm hybrids. Thirty-one treatments including control were replicated thrice with 200 worms per replicate post III^. Moult. For all the thirty hybrids, estimates for heterosis were worked out as per cent deviation from mid parent value. Different hybrids combinations exhibited significant and desirable heterotic estimate at egg, larval, cocoon and post cocoon stages when compared to check hybrid. Six hybrids viz. ND₂ × NSP, ND₂ x U₁, ND₂ ×JD₆, ND₃ × ND₂, ND₃×JD₆ and NSP ×JD₆ recorded positive heterosis for egg traits. For larval traits, eight hybrids viz., ND₂ × CSR₂, ND₃ × NSP, ND₃ × CSR₂, ND₃ × JD₆, U₁ × JD₆, CSR₂ × ND₂, CSR₂ × ND₃ and JD₆ × ND₂ were found to be heterotic. For commercially important cocoon parameters like coon yield by weight, by number, good cocoon and pupation percentage, significant heterosis was observed in twenty-three hybrids. Only one hybrid i.e. CSR₂ ×ND₃ exhibited heterosis above than control for single cocoon weight, single shell weight and shell ratio percentage. At post cocoon stage, only three hybrids viz. NSP × ND₃, NSP × U₁ and CSR₂ × ND₂ were significantly heterotic. The perusal of data on the basis of cumulative positive heterosis value of different traits revealed that, hybrid ND₂ × NSP (353.36) ranked at 1^st position followed by CSR₂ × ND₂ (333.17) and NSP × ND₃ (333.15) at number 2^nd position and 3^rd position respectively and were shortlisted and found promising for exploitation at commercial level after validation by having multi location trial before releasing in the field.