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为明确棉铃虫Helicoverpa armigera(Hübner)对苏云金芽胞杆菌Bacillus thuringiensis(Bt)Cry1Ac毒蛋白抗性的稳定性及其适合度变化,利用生物测定的方法研究了Cry1Ac抗性品系棉铃虫转到正常饲料饲养后的抗性衰退及再次筛选后抗性的恢复情况,并比较了敏感、抗性和抗性衰退后各品系间的适合度差异。在失去选择压的情况下,高抗品系棉铃虫对Cry1Ac的抗性迅速衰退,经过4代后抗性水平由最初的3626.67倍下降到1436.67倍;到第12代时抗性水平已低于10倍,随后品系保持较稳定的低抗水平;当重新进行抗性再筛选时,其抗性水平可快速恢复,抗性倍数快速回升,5代后恢复到1123.33倍。与敏感品系相比,高抗棉铃虫品系的适合度明显降低,相对适合度仅为0.33,但转到正常饲料连续饲养14代后,棉铃虫适合度明显上升,相对适合度为0.87,主要表现为卵孵化率和幼虫存活率等显著提高。
In order to clarify the stability and fitness of cotton bollworm Helicoverpa armigera (Hübner) against Cry1Ac toxin of Bacillus thuringiensis (Bt), the transgenic cotton bollworm (Helicoverpa armigera) The resistance decline and the resumption of resistance after screening again. The differences of fitness between the lines after the decline of sensitivity, resistance and resistance were compared. In the absence of selective pressure, the resistance of Cry1Ac-resistant strains of H. armigera to the Cryptophila decreased rapidly from the first 3626.67 fold to 1436.67 fold after the fourth generation. The resistance level to Cry1Ac was lower than 10 at the 12th generation Afterwards, the strain maintained relatively stable and low anti-resistance level. When the rescreening was resumed, the resistance level recovered rapidly and the resistance fold increased rapidly, then returned to 1123.33 times after 5 generations. Compared with the susceptible lines, the suitability of high-resistant bollworm strains decreased obviously, the relative fitness was only 0.33, but when fed to normal feed for 14 generations, the fitness of cotton bollworm increased obviously, the relative fitness was 0.87, For egg hatchability and larvae survival significantly increased.