Evaluation of Thermotolerant Bivoltine Silkworm Breeds through Cocoon Yield and Filament Characteristics against Beauveria bassiana (Bals-Criv.) Vuill. Inoculation

Silkworm, Bombyx mori L. being a poikilothermic insect is susceptible to both biotic and abiotic factors. The present study was carried to assess the performance of few thermotolerant bivoltine silkworm breeds under high temperature treatment (36 ± 1⁰ C for 6 hours) and Beauveria bassiana (Bals-Criv.) Vuill. inoculation (6.86 ̕X 104 spores / ml @ 0.5 ml / silkworm). Seven thermotolerant bivoltine silkworm breeds viz., B1, B2, B4, B6, B8, APS12, and APS45 and two popular bivoltine breeds, CSR2 and CSR4 breeds and one popular multivoltine breed Pure Mysore were utilized for the study. Among the thermotolerant breeds studied, the breed B4 was found to perform better with respect to cocoon yield by number, cocoon yield by weight, average filament length, filament weight under both high temperature treatment and B. bassiana inoculation. CSR4 breed was found to be least performer for all the parameters. Therefore, the breed B4 can be a better parent for hybridization and improvement under both the stress conditions.