抗杀虫双和抗杀螟丹小菜蛾近等基因系的培育

Selection of near isogenic line strains ofdimehyporesistance and cartapresistance indiamondback moth, Plutella xylostella L.

将小菜蛾抗性品系与敏感品系杂交，Ｆ１代用能杀死全部敏感个体和部分杂合个体的剂量进行选择；存活个体与敏感品系回交，其后代再用上述适量药剂进行选择；存活个体与敏感品系回交。通过１２代回交，建立了抗杀虫双和抗杀螟丹近等基因系，并对其多功能氧化酶环氧化活性和生物学特性进行了比较研究。结果显示：（１）抗杀虫双和抗杀螟丹小菜蛾近等基因系的艾氏剂环氧化活性均高于敏感品系，分别为１．５６倍和１．９７倍；（２）在回交后代中，抗性水平逐代降低。小菜蛾对杀虫双和杀螟丹的抗性并未付出明显的生物学代价。

F1 cross was made by mating between resistant and susceptible strains.F1 progeny was selected by the dose that kills essentially all susceptible homozygotes(SS)but it causes relatively little mortality of heterozygotes(RS).The surviors were backcrossed to susceptible individuals.A near isogenic line strain(NILs)was selected by repeated back crossing.Two NILs of dimehyporesistance(Rd)and cartapresistance(Rp)were selected by 12 generations back crossing.The epoxide activities and biological characteristics of NILs were compared with those of susceptible strain,and Rd and Rp strain.The results indicated that the epoxide activities of NILs of Rd and Rp increased by 156fold and 197fold respectively.The resistant level was declined with increasing of backcross generations.The resistance to dimehypo and cartap did not decrease the biological characteristics in diamondback moth