利用黑色斑蚕作亲本、选育日系普斑限性品系

根据家蚕Bombyx moli斑纹互作原理,利用2032限性品种的雌,与自然突变体雄杂交。F2代出现分离,于是淘汰所有黑色斑蚕,只留下普斑蚕和素斑蚕,即得到新限性普斑系。新限性品系得到后,做连续3代的系统选育,其中F3代为蛾区混合育,F4～F5代采用单蛾育。蛾区混合育着重个体选择,单蛾育以蛾区选择为主,个体选择为辅。性状基本稳定后,即初步对其作主要经济性状的测定。结果显示:新限性品系在5龄经过、全龄经过上比两亲本略短。在全茧量、茧层量、茧层率几项指标上较两亲本为优,分别比两亲本平均值提高31%、38%、5%。

Selection and breeding of sex-limited silkworm strain of normal marldng of Japanese strain using black marking silkworm as parent

Based on sex-inheritance of the striped Bombyx moli the females of sex-limited strain 2032 were used to hybridize with the males of natural mutants. As there was separation from F2 generation, all black marking silkworms were discarded, and the normal and the plain marking silkworms were reserved, so as to obtain the new sex-limited normal marking strain. Then systematic selection and breeding were conducted for three generations, in which F3 was mixed rearing and F4 - F5 was individual rearing. It was emphasized individual selection for mixed rearing and it was mainly interbatch selection and subsequently individual selection in individual rearing. After the traits became stabilized, the economic traits were measured. The results showed that the duration of the 5th instar and all instars of new sex-limited strain was slightly shorter than those of the parents. The weight of whole cocoon, amount of cocoon shell, and rate of cocoon shell of new sex-limited strain was improved 31% , 38% , and 5 % , respectively, than those of the parents.