Research Progress on Chinese Silkworm Germplasm Resources and Variety Breeding

As the birthplace of the world’s sericulture and the original center of silkworms, China has a long history of silkworm breeding and widely distributed sericultural areas. After long- term artificial selection and natural elimination, silkworm varieties have been differentiated and multiplied, making China abundant in silkworm germplasm resources. We have summarized the research actualities of Chinese silkworm germplasm resources as follows: at present, there are more than 4,500 silkworm germplasm resources, which are stored in 32 scientific research and teaching institutions in 27 provinces and cities of China. The resources fall into several major categories, under which are local varieties, improved varieties, imported varieties, multivoltine varieties, germplasm innovation materials and basic materials, gene mutation systems, tester strains and near-isogenic lines. By use of various germplasm resources, the People’s Republic of China had bred 204 new silkworm varieties by 2010 since its founding. According to usage, these resources are divided into 103 varieties for spring rearing and spring-autumn rearing, 85 varieties for summer-autumn rearing and 16 varieties for specialpurpose rearing. Some of these varieties were as transient as a fleeting cloud, whereas some others have become classics and made outstanding contributions to the development of China’s sericulture.