棉铃虫对转Bt基因棉的抗性筛选及遗传方式的研究

通过室内筛选获得了棉铃虫Helicoverpa armigera (Hübner)对转Bt基因棉的抗性种群，并在此基础上进行了抗性遗传方式的研究。试验结果表明：经16代筛选，棉铃虫对转Bt基因棉的抗性倍数上升到43.3倍。筛选过程中，棉铃虫7日龄幼虫的体重和成虫羽化率变化明显，被选为确定筛选剂量的标准。敏感与抗性棉铃虫杂交，正交、反交的显性度都小于0、杂交过程中雌雄性比基本接近1∶1、假设抗性基因为单基因时的χ²值较低，因此，初步认为棉铃虫对转Bt基因棉的抗性是常染色体单基因控制的不完全隐性遗传。

Study on screening and inheritance mode of resistance to Bt transgenic cotton in cotton bollworm

Laboratory screenings were conducted for obtaining resistant population of cotton bollworm (CBW) Helicoverpa armigera (Hübner) to Bt transgenic cotton. The mode of inheritance of resistance in this population was also studied. The results showed that after selection for 16 generations, the WLC₅₀ (mean weight loss concentration) of CBW to Bt transgenic cotton was 43.3 times as many as that of the 1st generation. Owing to that the weights of the 7-day old larvae and emergence rate of adults, when fed on diets containing Bt transgenic cotton, changed significantly, these two characters were regarded as the resistance standards for screening in this study. The degrees of dominance of cross and reciprocal-cross between the resistant and susceptible populations were less than 0 according to Stone's formula. The sex ratios of the descendants of the cross and backcross groups were 1∶1 approximately. The χ² values were low as if the resistance of CBW to Bt transgenic cotton was controlled by a single gene. It is suggested that the inheritance of resistance to Bt transgenic cotton in CBW is controlled by single autosomal incomplete recessive allele.