Genetic Diversity and Differentiation of Silkworm (Bombyx mori) Local Germplasm Resources in China and Uzbekistan

Silkworm (<i>Bombyx mori</i>) is an economically significant insect that produces silk and makes important contributions to the development of silk-producing countries. The genetic diversity and unique adaptive traits of silkworm germplasm resources form the foundation for breeding efforts. In various geographical regions, silkworm have developed distinct traits through long-term adaptive selection. In this study, we focused on identifying and evaluating representative silkworm germplasm resources from both China and Uzbekistan. We discovered notable differences in the morphology and production traits of local silkworm strains, likely influenced by differing geographical environments. It is also possible that China has a long history of silkworm rearing and after a long time of breeding selection, the diversity of silkworm morphology is less than that of Uzbekistan, but the production characteristics are more suitable for silk utilization. Phylogenetic analysis based on genomic comparisons revealed that Uzbekistan's local silkworm strains are positioned between China's local and improved strains. This suggests that Uzbekistan silkworms primarily originated from China. The further analysis of genetic diversity and strain differentiation highlights the unique differences of each country's silkworms, especially in terms of genetic diversity on chromosome 1 (sex chromosome). By identifying and evaluating these germplasm resources and linking them to unique advantageous traits, it provides a scientific basis for improving cocoon silk quality and optimizing sericulture productivity.