Evaluation of selected bivoltine breeds of silkworm (Bombyx mori L.) for economic characters under sub-tropical conditions of Jammu

Abstract

The experiment was carried out to assess ten selected bivoltine breeds of silkworm viz., CSR-2, CSR-4, CSR-26, CSR-27, RSJ-1, RSJ-3, SH6, NB4D2, JAM-1 and JAM-2 for economic characters under sub-tropical conditions at Regional Sericultural Research Station (RSRS), Central Silk Board, CSB Complex, Miran Sahib, Jammu during Spring, 2024. Based on the analysis of larval and cocoon parameters viz., maximum fecundity was recorded in NB4D2 (583), hatching percentage in RSJ-1 (95.67%), total larval duration in CSR-27 (25:09), matured larval weight in JAM-2 (52.89 g), effective rate of rearing (by number) in SH-6 (9589.00), effective rate of rearing (by weight) in CSR-26 (16.80 kg), single cocoon weight in CSR-26 (1.84 g), single shell weight in CSR-2 (0.39 g), shell ratio in CSR-2 (21.90%) and pupation percentage in RSJ-1 (97.44%) breeds of silkworm. Whereas, based on the analysis of post-cocoon parameters viz., maximum average filament length was recorded in SH-6 (1016.00 m), average non-breakable filament length in SH-6 (896.00 m), denier in CSR-26 (2.77), raw silk percentage in NB4D2 (34.06%), renditta in RSJ-1 (7.47) and reelability percentage in CSR-26 (90.82%) breeds of silkworm. The overall average evaluation index values calculated by considering all the economic parameters (cocoon and post-cocoon parameters) ranged from 45.69 to 56.25. Four silkworm breeds viz., CSR-2 (56.25), CSR-26 (54.19), SH-6 (52.96) and CSR-27 (50.60) recorded >50 average EI values. The silkworm breeds viz., CSR-2, CSR-26, SH-6 and CSR-27 can be utilized for further breeding programme for development of superior hybrids under sub-tropical climatic conditions of Northern India.