棉铃虫对Bt杀虫剂的抗性遗传方式

随着转基因棉花种植面积的日益增加，棉铃虫Helicoverpa armigera（Hübner)对Bt的抗性已经成为一个不容忽视的问题。发展转多价基因作物是当前缓解害虫对Bt抗性的最有效措施。本研究以经室内多年筛选的、抗性倍数达2 000多倍的Bt杀虫剂（含多种蛋白）抗性品系为材料，通过生物测定和不同的杂交试验，测定棉铃虫对Bt杀虫剂的抗性遗传方式，以期为Bt生物农药的抗性治理提供一定的依据，同时为制定棉铃虫对转多基因作物的抗性治理策略提供一定的参考。对敏感亲本和抗性亲本杂交产生的F1代的研究结果表明，杂交品系的抗性倍数分别为22.2倍和24.6倍;抗性显性度D值均小于0，分别为-0.20和-0.17，抗性为常染色体不完全隐性遗传。对4种回交后代和2种自交后代F2的研究结果表明，实际死亡率与期望死亡率差异较大，说明抗性是由单基因多个位点或多基因控制。

Inheritance of resistance to Bacillus thuringiensis insecticide in Helicoverpa armigera (Hübner)(Lepidoptera :Noctuidae)

As the growing area of Bacillus thuringiensis （Bt) transgenic cotton has been extending increasingly, the development of resistance to Bt in the cotton bollworm （CBW), Helicoverpa armigera （Hübner), has become a decisive problem that should not be overlooked. To develop polygenic genetically modified plants is the most effective measure for delaying the resistance of insect pest to Bt transgenic plants and Bt insecticide. In this study, a resistant strain of CBW which had been selected for more than 100 generations and had more than 2 000-fold resistance to Bt insecticide （a product of B. thuringiensis subspecies kurstaki （Btk) including a variety of toxin proteins) was used to test the inheritance mode by bioassays and various hybridizations. The objective of this study is to provide the theoretical basis for the resistance management strategy of Bt commercial formulation, and provide the reference for establishing the resistance management strategy of CBW to the polygenic genetically modified plants. The two progenies of reciprocal parental crosses between the resistant and the susceptible strains responded alike in bioassays. The resistance ratios for FSR and FRS reached 22.2 and 24.6-fold, respectively; the degrees of dominance for FSR and FRS were less than 0 （from -0.20 to -0.17), and the resistance was autosomal and incompletely recessive inheritance. Analysis of progenies from four backcrosses of F1 with the susceptible strain and two F1 by F1 crosses showed that significant deviation occurred between the observed and the expected mortality, suggesting that the resistance is controlled by more than one locus.