FILAMENT SIZE VARIATION IN POLYVOLTINE BREEDS OF THE SILKWORM, BOMBYX MORI L.

摘要

The size of the bave varies greatly with breeds of the silkworm. Even the size of the fibre of same cocoon varies at different parts. In the present study, filament size variation in 22 polyvoltine breeds of the silkworm Bombyx mori L. was studied. Data indicated that the size of the filament decreased from the outer to the inner layer. The decrease in filament size was sudden in some breeds whereas it was gradual in others. The slope of the denier was gradual in BL68 (-0.00268) and MY1 (-0.00295). In the case of BL43 (-0.00725) and BL24 (-0.00653), the slope was sudden in nature. In silkworm breeding programmes, breeds with gradual slope have to be selected in order to improve the fibre quality.