小菜蛾对丁烯氟虫腈的抗性遗传力及风险评估

Realized heritability of resistance to butene-fipronil in diamondback moth,Plutella xylostella

采用丁烯氟虫腈对小菜蛾敏感品系进行室内抗性筛选,饲养15代,汰选13代,平均成活率为35.12%,获得抗性品系(R),与敏感品系(S)比较,抗性指数为90.27倍。应用域性状分析法,研究小菜蛾对丁烯氟虫腈的抗性现实遗传力,并对不同杀死率下抗性发展速率进行预测。结果表明,连续筛选前7代(F0～F6),小菜蛾对丁烯氟虫腈的抗性现实遗传力为0.2332;不连续筛选后6代(F7～F14,8代中有2代未筛选),现实遗传力为0.0203。整个13代筛选期间,现实遗传力为0.2206。假设遗传力为室内筛选估算值的一半、死亡率为50%～90%,预计小菜蛾对丁烯氟虫腈抗性增长10倍,需要约22.8～10.3代。

The resistance of fourth instar larvae to the insecticide increased 90.27-folds under the new insecticide, butene-fipronil pressure which used to diamondback moth, Plutella xylostella （ L. ） for 13 generations. Estimation of realized heritability （h2） of resistance was studied based on the Tabashnik＇ s method. The results suggested that the realized heritability estimated from early selection stage was significandy higher than that from later stage, the realized heritability was 0. 2332 for F0 - F6, consecutive selection for 7 generations and 0. 0203 for F7 - E14, during which there a total of 2 generations without selection, h2 for the entire selection experiment was 0. 2206. Assuming that the h2 of field Plutella xylostella population was half that of indoor populations, it required 22.8 - 10.3 generations for butene-fipronil to obtain 10-fold increase in LD50 under selective pressure of 50% -90% mortality for each selective generation.