Abstract: 【Objective】To construct the new male silkworm hybridized combination Qiuhua×Ping30 by crossing sex-limited marking variety Qiuhua and Ping30.【Method】Using the sex-linked balanced lethal line S-14 introduced from Russia as donor and excellent commercial variety Baiyun as receptor, a new sex-linked balanced lethal line Ping30 with fine economical characters was bred out by the designed method of sex-control gene transferring. 【Result】 The identified results indicated that male silkworm rate of new variety attained 99.8% with good viability and fine quality cocoon filament, such as the raw silk percentage of fresh cocoon increased 26.11% and the comprehensive economical benefits increased 26.63% compared with the control variety. 【Conclusion】Qiuhua×Ping30 has been passed the identification of new silkworm variety in Zhejiang Province and became the first identified commercial male silkworm variety in the world. The extending results also showed that the new male silkworm variety had a warm reception in the farmers and silk factories, hinted a favorable application future.

Key words: silkworm, sex-linked balanced strain, male silkworm variety, Breeding