不同地区甜菜夜蛾种群的遗传多样性分析

甜菜夜蛾Spodoptera exigua (Hübner)是一种重要的农业害虫，曾给我国农牧业生产造成过重大的经济损失。为了阐明甜菜夜蛾的种群动态规律，改善和提高其预测、防治水平，我们应用扩增片段长度多态性(AFLP)技术对我国7个甜菜夜蛾种群的42头雄蛾的遗传多样性进行了研究分析。结果表明，不同种群个体间遗传相似性指数分布在0.143～0.824之间，同一种群内不同个体间的遗传相似性指数分布在0.250～0.786之间，同一种群内个体间的遗传相似性指数有许多小于不同种群个体间的。江西种群的多态性条带比例最低，为80.7%； 山东种群的多态性条带比例最高，达88.6%。总体而言，北方种群内的遗传多样性高于南方种群。聚类分析结果表明，同一种群的个体并不总能聚在一起，即种群间不存在明显的遗传分化。这些结果为明确我国甜菜夜蛾的迁飞规律及各发生危害区的虫源关系提供了进一步的实验依据。

Analysis of genetic diversity in different geographic populations of the beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae ) with AFLP technique

The beet armyworm Spodoptera exigua(Hübner) is a serious insect pest and has caused serious economic losses in China in last decade. For further understanding the population dynamics and improving the forecast and control of this species, the DNA polymorphism of 7 geographic populations from various locations of mainland China was analyzed by using amplified fragment length polymorphism (AFLP) technique. The results showed that the maximum genetic similarity of S. exigua individuals between geographic populations was 0.824, and the minimum was 0.143;  the maximum genetic similarity of S. exigua individuals within geographic populations was 0.786 and the minimum was 0.250. The genetic similarity of some samples within geographic populations was lower than that of some samples between geographic populations. The genetic diversity of Jiangxi population was the lowest (the proportion of polymorphic bands was 80.7%) and that of Shandong population was the highest (the proportion of polymorphic bands was 88.6%). The genetic diversity of S. exigua from northern areas was higher than that from southern areas on the whole. The results of cluster analysis showed that 42 individuals of 7 populations did not relate to the geographic locations where they were collected, suggesting that the genetic differentiation is not obvious in all the populations studied. The northward and southward migration by the adult beet armyworm is the most possible explanation for these results, since other direct or indirect evidences has shown that it is a true migrant species in the country.