转双价基因棉对高抗Bt棉棉铃虫的抗虫性

采用喂饲法，测定了转双价基因棉(中棉41、SGK321)、转单价基因棉(中棉29)及常规棉(苏棉12)对抗性和敏感棉铃虫的抗虫性。结果表明：转双价基因棉主茎叶片对抗性和敏感棉铃虫初孵幼虫的抗虫性明显高于或稍高于转单价基因棉，且随棉花生长发育期的推移抗虫性下降速度较慢，如第8叶后中棉41(ZM41)对抗性和敏感初孵幼虫的平均死亡率分别为80．0％～40．0％和100％～85．6％，而中棉29(ZM29)分别为30．0％～15．6％和84．0％～71．1％。转单、双价基因棉生长中后期主要受害部位对抗、感棉铃虫的抗性高低次序均为：嫩蕾、顶部嫩头、侧枝嫩叶，其中转双价基因棉嫩蕾对敏感棉铃虫和顶部嫩头对抗性棉铃虫的抗虫性显高于转单价基因棉。转单、双价基因棉对抗性棉铃虫的抗虫性低于敏感棉铃虫。

Resistance of dual-toxin transgenic cotton to high level resistant strain of Helicoverpa armigera(Hübner)to Bt cotton

The resistance of dual-toxin transgenic cotton ZM41,SGK321 and single-toxin transgenic cotton ZM29,non-transgenic cotton SM12 to neonates of susceptible and resistant Helicoverpa armigera were determined using feeding bioassay.The results showed that the resistance of the dual-toxin transgenic cotton to both resistant and susceptible neonates were obvious or slightly higher than those of the single-toxin transgenic cotton,and the resistance of dual-toxin decreased slower than those of the single-toxin with increase of the cotton growing stage.The mean mortality of the 8th15th leaf on the main stem of ZM41 to resistant and susceptible neonates were 80.0%40.0% and 100%85.6%,respectively,and those of ZM29 were 30.0%15.6% and 84.0%71.1%,respectively.The order(from high to low)of insect resistance of the important organs to the resistant and susceptible H.armigera in the mid-late growing stage were:tender square,terminal leaf on the main stem,tender leaf on the lateral branch.And the insect resistance of tender square to susceptible neonates and the terminal leaf on the main stem to resistant neonates of dual-toxin transgenic cottons was higher than that of single-toxin transgenic cotton in the mid-late growing stage.The mean mortality of single- and dual-toxin transgenic cotton to the resistant neonates were lower than those to the susceptible neonates.