施用噻虫嗪可降低B型烟粉虱群体的遗传多样性

用4个具有多态性的微卫星位点（BEM15、BEM25、BEM31和BT-b53）分析了施用化学农药噻虫嗪 （thiamethoxam）对B型烟粉虱Bemisia tabaci（Gennadius）群体遗传结构的影响。结果表明：噻虫嗪汰选18代的B型烟粉虱处理种群（抗性种群）抗药性上升到对照种群（敏感种群）的19.08倍，同时其微卫星位点不同等位基因频率分布发生了变化，等位基因数（N_a）平均值由2.750降到2.250，杂合度（h）平均值由0.459降到0.299（降低了34.8%），多态信息含量（PIC）平均值由0.393降到0.250，有效等位基因数（N_e）平均值由2.051降到1.488；抗性种群与敏感种群的标准遗传距离为0.15。结果提示，化学农药的施用可能是B型烟粉虱群体遗传结构的重要影响因素之一。

Thiamethoxam application can decrease the genetic diversity of Bemisia tabaci (Gennadius) biotype B

The effects of the application of thiamethoxam on the genetic structure of invasive Bemisia tabaci(Gennadius)biotype B were analyzed using four polymorphic microlsatellite loci.The results showed that resistance of B.tabaci biotype B selected by thiamethoxam for 18 generations was 19.08 times that of the susceptible population.Compared with the genetic structure of the control population(susceptible population),the distribution of the allele frequency also changed.Meanwhile,the average value of number of alleles(N_a)decreased from 2.750 to 2.250;gene heterozygosity(h)decreased from 0.459 to 0.299;polymorphism information content(PIC)decreased from 0.393 to 0.250;and the effective number of alleles(N_e)decreased from 2.051 to 1.488.The standard genetic distance between the susceptible and resistant populations was 0.15.The results suggested that application of insecticide might be one important factor affecting the genetic structure of B.tabaci biotype B.