【目的】为了明确南繁区稻瘟病菌(Magnaporthe oryzae)的遗传分化情况,【方法】采用AFLP分子标记技术对南繁核心区(三亚、乐东和保亭)和非核心区(琼中、屯昌和定安)共60个稻瘟病菌菌株的遗传多样性和群体遗传结构进行了比较分析。【结果】聚类分析表明,几乎所有菌株都聚在同一个谱系里,并且该谱系没有明显的亚群;群体遗传结构分析表明,核心区群体的多态性位点百分率、Shannon信息指数和基因流分别为 87.89%、0.2738和4.2897,高于非核心区群体的 81.37%、0.2703和3.5892;然而,核心区群体的Nei基因多样性指数和基因分化系数分别为 0.1657和0.1044,低于非核心区群体的 0.1662和0.1223。【结论】这些结果表明核心区和非核心区菌株都存在丰富的遗传多样性,不同群体间均存在较多的基因交流,但遗传变异均主要来自群体内;相比之下,核心区菌株的遗传多样性和遗传分化程度较高。

【Objective】 In order to clarify the genetic differentiation of Magnaporthe oryzae in South China Crop Breeding Area in Hainan Province, 【Method】the genetic diversity and population genetic structure of 60 Magnaporthe oryzae isolates collected from the core region (Sanya, Ledong and Baoting) and non-core region (Qiongzhong, Tunchang and Ding’an) of South China Crop Breeding Area were comparatively analyzed using amplified fragment length polymorphism(AFLP) technique. 【Result】The cluster analysis showed that almost all isolates were clustered in one group, and there was no obvious subgroup. The analysis of population genetic structure showed that the percentage of polymorphic loci(PPL), Shannon’s information index(I) and gene flow(N_m) in the core population were 87.89%, 0.2738 and 4.2897, respectively, higher than those of non-core population whose PPL, I and Nm were 81.37%, 0.2703 and 3.5892, respectively. However, Nei’s gene diversity index(H) and genetic differentiation coefficient(G_st) in the core population were 0.1657 and 0.1044, lower than those of non-core population whose H and G_st was 0.1662 and 0.1223. 【Conclusion】 These results showed that there were rich genetic diversity in both isolates of core and non-core regions and wide gene flow existed among these populations, but the genetic variation was mainly within the population. In contrast, the genetic diversity and the degree of genetic differentiation in the isolates of core region were relatively larger.