Comparison of Cocoon and Post-Cocoon Parameters of Commercial Silkworm (Bombyx mori L.) Crossbreeds MV1 × S8 and PM × FC2 in Kolhapur, Maharashtra, India

Abstract

Background: Commercial silkworm performance is influenced by genetic background, nutrition, rearing environment, and post-cocoon processing conditions. Region-specific comparisons are therefore most informative when their experimental limitations are made explicit. Objective: This study compared cocoon, rearing, and post-cocoon traits of the commercial crossbreeds MV1 × S8 and PM × FC2 under the conditions of a single research facility in Kolhapur, Maharashtra. Methods: Three rearing batches were conducted in January–February, April–May, and September–October 2025. Each batch used 10,000 larvae per crossbreed, and 20 good-quality cocoons per batch were sampled for cocoon and reeling measurements. Batch-level observations were summarised as mean ± SD. Inferential testing was not retained in the revised analysis because there were only three batch-level observations per crossbreed, batches coincided with seasons, and the crossbreeds were maintained in separate rearing houses. Results: Across the three batches, PM × FC2 had higher mean single-cocoon weight (1.713 ± 0.032 g vs. 1.361 ± 0.023 g), shell weight (0.319 ± 0.008 g vs. 0.222 ± 0.004 g), shell ratio (18.66 ± 0.12% vs. 16.34 ± 0.08%), filament length (819.8 ± 12.1 m vs. 613.0 ± 8.7 m), reelability (87.1 ± 0.55% vs. 81.9 ± 0.70%), raw-silk percentage (17.65 ± 0.19% vs. 15.29 ± 0.18%), cocoon yield (70.27 ± 2.15 vs. 53.23 ± 0.91 kg/100 dfls), and effective rate of rearing (95.7 ± 0.46% vs. 92.4 ± 0.53%). Mean filament fineness was lower for PM × FC2 (2.84 ± 0.03 denier vs. 3.20 ± 0.02 denier). Renditta, recalculated directly from the reported raw-silk percentage as 100/raw-silk percentage, averaged 5.67 ± 0.06 for PM × FC2 and 6.54 ± 0.08 for MV1 × S8. Conclusion: Within these three location-specific batches, PM × FC2 showed a consistently more favourable descriptive profile for several cocoon and reeling traits. The design does not establish genetic superiority or broad regional advantage; replicated trials using independent rearing units, recorded batch-level environmental data, and multi-location testing are required before wider recommendations are made.