人工模拟“庇护所”和“非庇护所”条件下棉铃虫对Bt棉的抗性演变

 人工饲料中添加转Bt基因杂交棉品种中棉所29棉仁粉,建立杂交和自交品系分别模拟“庇护所”和“非庇护所”条件,连续多代进行棉铃虫对Bt棉的抗性筛选。结果表明：经11代筛选,棉铃虫自交品系和杂交品系的幼虫死亡率下降,体重和体长增加,幼虫历期缩短,化蛹率和羽化率增加。依据幼虫死亡率、体重、体长、幼虫历期以及化蛹率、羽化率等生命参数的演变,相较杂交品系,自交品系对Bt棉能更快地产生适应性。11代筛选后,利用不同抗性品系棉铃虫进行转基因棉抗虫性评估,结果表明：相比敏感品系,杂交品系测定4个转基因棉品种的抗虫性等级未发生变化,而中棉所29等3个转基因棉品种对棉铃虫自交品系的抗性下降了1个等级。对Bt制剂的抗性测定结果表明,杂交品系的抗性倍数为2.5215,自交品系的抗性倍数为9.3876。据本研究初步结果,利用“庇护所”策略延缓棉铃虫对转Bt基因棉的抗性产生是可行的。

Studies on Resistance Evolution of Cotton Bollworm to Bt Transgenic Cotton in Artificial Simulating "Refuges" and "Non-refuges" Conditions

n order to find out the resistance evolution of Helicoverpa armigera(Hübner) to Bt cotton, "refuges" and "non-refuges" conditions were simulated. Laboratory screening was conducted for obtaining the resistant strains of inbred and hybrid line feeding on the artificial diet which contained cotton seeds powder from Bt hybrid CCRI 29. The results showed that: screening for 11 generations, the mortality rates of inbred strain and hybrid strain of H. armigera larva decreased, larval weight and larval length increased, the larval duration shortened, pupation rate and emergence rate increased. Contrast with the hybrid strain, the inbred strain adapted faster to Bt transgenic cotton. Screening for 11 generations, using different resistant strains of cotton bollworm for transgenic insect-resistance assessment, results indicated that the resistance grade of phase-sensitive strains determination of four insect-resistant transgenic cotton cultivars did not change, and resistance grade of three transgenic varieties to self-bred lines from CCRI 29, Nankang-3, and Kemian-1 decreased by one. The resistance ratio of self-strain and hybrid strain to Bt preparations was 9.3876 and 2.5215, respectively. According to the preliminary results of this study, the policy of "refuges" to delay the resistance of cotton bollworm to Bt transgenic cotton is feasible.