Evaluation of nutritional indices and conversion efficiency in multivoltine, cross-breeds and popular bivoltine double hybrid of mulberry silkworm Bombyx mori

Abstract

In sericulture, the nutritional ability of mulberry varieties and conversional traits of silkworm breeds have an important role in the improvement of silk yield. The present study aims to evaluate silk conversion efficiency in a few breeds and hybrids. The silkworm Bombyx mori breeds and hybrids viz., MVI, PMxCSR2, MV1xS8 and FC1xFC2 were assessed during the fifth instar, with PM as control during the years 2019 and 2020. The study focused on the nutritional indices and conversion traits of silkworms by feeding V1 mulberry leaves, reared under the same environmental conditions. Significant variations were observed among silkworm breeds and hybrids. The test breed and hybrids were found superior to the control PM, which recorded an ingestion of 2.33g and a conversion ability of 8.65%. The bivoltine double hybrid FC1xFC2 showed high food ingestion (3.25g) and conversion (18.18%), followed by the cross breed MV1xS8 with moderate ingestion (3.17g) and conversion (16.63%). The values for ingesta and conversion in PMxCSR2 were 3.43 g and 8.92%, respectively. Further, in respect of Efficiency Conversion of Ingesta (ECI) of shell, the highest conversion of shell is shown by FC1xFC2 (13.56%) followed by MV1xS8 (10.14%), MV1 (9.73%) and PMxCSR2 (9.36%), having a percentage difference of 63.27%, 36.08%, 32.11% and 28.30% respectively over PM. The silk conversion efficiency of bivoltine double hybrid FC1xFC2 was found to be profoundly high, followed by multivoltine cross-breeds and pure line (PM) tested.