小菜蛾对Bt毒素Cry1Ac和Bt制剂抗性的选育及其抗性种群的生物学适应性

用Bt制剂和Bt毒素Cry1Ac分别对源自深圳田间的小菜蛾Plutella xylostella在室内进行抗性种群选育，获得相对抗性倍数分别为24.36、38.16倍的抗性种群DBM.1Ac-R30和DBM.Bt-R46。对这2个抗性种群及其敏感种群（DBM.Bt-S）的生长发育、存活及繁殖特征进行了详细地观察与比较，并以甘蓝为饲喂材料构建了2个抗性实验种群的生命表。结果表明，DBM.1Ac-R30和DBM.Bt-R46种群较DBM.Bt-S种群的产卵量和孵化率下降，幼虫发育历期延长，雌雄比显著降低，雌成虫数量、寿命减少。DBM.1Ac-R30和DBM.Bt-R46种群相对于DBM.Bt-S种群的相对适合度分别为0.75和0.65，抗性种群在繁殖能力上存在明显的生存劣势。

Resistance selection of Plutella xylostella by Cry1Ac toxin and Bt formulation and biological fitness of the resistant populations

Two diamondback moth populations, DBM.1Ac-R30 and DBM.Bt-R46, with resistant ratios of 24.36 to Cry1Ac and 38.16 to Bt were obtained after 30 and 46 generations of selection with Cry1Ac toxin and Bt formulation respectively in the laboratory. The basic biological properties, such as developmental, reproductive and  survival characteristics, of the above two resistant populations and their unselected parent population DBM.Bt-S were studied. The results showed the DBM.1Ac-R30 and DBM.Bt-R46 had a fitness value of 0.75 and 0.65 relative to the susceptible DBM.Bt-S population, respectively. These resistant populations showed reproductive disadvantages, including lower number of eggs laid and hatching rate, prolonged larval period, lower sex ratio （♀∶♂）, and shorter life-span and less number of female adults compared with the susceptible population.