Impact of Seasonal Variations on Filament Length and Non-Broken Filament Length in Relation to Silk Reeling Performance

Mulberry silk production in West Bengal and northeastern India, primarily involving bivoltine and multi-bi hybrid silkworm varieties, is a cornerstone of the sericulture industry. However, seasonal climatic variations, characterized by elevated temperatures and humidity, significantly affect cocoon quality, posing challenges to silk reeling efficiency and productivity. This study examines the influence of seasonal variations on the quality and reeling performance of bivoltine and multi-bi hybrid silk cocoons in these regions. Key parameters, including filament length (FL), non-broken filament length (NBFL), and shell ratio, were analyzed over five seasons. Results indicate a marked decline in cocoon quality during unfavorable seasons (June–July, August–September), with bivoltine cocoons exhibiting greater sensitivity through reductions in FL, NBFL, and reelability compared to the more resilient multi-bi hybrids. These seasonal impacts undermine reeling efficiency and silk yarn quality. Reeling speed varies across different seasons, ranging from 80 to 104 mpm for bivoltine cocoons and from 73 to 87 mpm for multi-bi cocoons. The findings emphasize the importance of adaptive rearing practices and technological innovations, such as multi-end reeling machines with enhanced speed and evenness control, to bolster productivity and address climatic challenges. This research provides critical insights for improving the sustainability and economic viability of sericulture in West Bengal and northeastern India.