Cocoon filament size deviation in bivoltine breeds/ hybrids of silkworm Bombyx mori

Silk, revered as the "Queen of Textiles," continues to command global attention due to its superior luster, softness, and resilience.In sericulture, filament uniformity and quality are directly influenced by the genetic traits of silkworm breeds and their hybrids.The present study evaluates the filament size variation among eight bivoltine parental breeds and their 12 hybrid combinations (both direct and reciprocal crosses) of Bombyx mori L. The findings indicate significant variation in filament length and denier across breeds and hybrids.CSR2 CSR4 exhibited the longest filament (1104 m), while FC1 FC2 recorded the highest average filament size (3.06 denier).Among parental breeds, CSR2 had the most uniform filament with the lowest average size (2.34 denier).Denier distribution patterns varied, with some hybrids showing consistent decrease from outer to inner layers, while others displayed fluctuations.These observations emphasize the importance of selecting specific hybrid combinations to optimize silk quality for commercial exploitation.