不同致害性褐飞虱种群的DNA多态性研究

采用RAPD-PCR方法，对分别在水稻品种TN1、Mudgo和ASD7上纯化82代的3个不同致害性褐飞虱种群的基因组DNA多态性进行了分析。从205个RAPD引物中筛选出了具种群特异性的引物10个，结果表明： 尽管未达到统计意义上的显著差异，雌、雄两性试虫种群间的遗传多样性一般高于种群内，种群内的多样性则以未经抗性品种筛选的TN1种群最高。用相似性系数进行类平均距离法聚类，能将同一致害性种群的各个个体与其他致害种群分开，雌、雄虫均无一例外，表明不同致害性种群间存在明显的遗传分化；同时雌、雄两性试虫分别归为2组，提示褐飞虱致害性遗传可能与性染色体连锁。不同致害性种群存在特有条带，有可能用于进一步建立褐飞虱个体致害性检测的分子标记。

The DNA polymorphism of host-associated populations of Nilaparvata lugens (St(a)l) with different virulence

The DNA polymorphism of the three host_related populations of Nilaparvata lugens, which differed in virulence and had been reared on rice variety TN1, Mudgo and ASD7 for 82 generations, respectively, was studied using RAPD_PCR technique. Of 205 RAPD primers, 10 with population_specific amplified bands were selected. The results showed that the genetic diversity among populations was greater than that within populations and the TN1 population reared on susceptible rice variety showed the largest genetic variation, although the differences between different populations were not statistically significant. In the dendrogram obtained with UPGMA analysis based on the standard of similarity index (SI), every female individual of a population could be clustered into a group with no exception, and so does the male. This provided the first clear evidence confirming that significant genetic differentiation exits between host_associated N. lugens populations with different virulence. It was also found that male and female individuals were grouped into two discrete classes, which suggested that the inheritance of virulence of N. lugens may be associated with the sex chromosome. Some amplified DNA bands were population_specific, which were useful to develop a molecular marker to examine the virulence of N. lugens at the individual level.