西瓜枯萎病菌遗传分化研究

Study on Genetic Differentiation of Fusarium oxysporum f.sp. niveum

本试验利用21个RAPD随机引物对50个西瓜枯萎病菌系进行了RAPD扩增，研究了病菌遗传多样性。结果表明，对供试菌系扩增出134条带，其中多态性带113条，占总带数的84．3％。菌系间的遗传相似系数变化在0．45-0．93之间，多数菌系间的同源程度较低。基于RAPD标记聚类分析表明，50个菌系划分为6个RAPD群（RAPD groups，简称RGs），即RGⅠ，RGⅡ，RGⅢ，RGⅣ，RGV和RGⅥ。其中RGⅠ和RGⅡ各含有一个菌系，分别来自秦皇岛和新疆；RCⅢ和RGⅤ包括2个菌系，分别来自秦皇岛、承德和廊坊、沧州；RGⅣ包括唐山、石家庄、邯郸和新疆菌系；其余的菌系属于RGⅥ。分类结果进一步说明西瓜枯萎病菌间存在着较大的遗传分化。

Fifty isolates of Fusarium oxysporum f. sp niveum were RAPD analyzed by using 21 random primers. The result showed that 134 RAPD bands were amplified, among them, 113 （ 84.3 % ） bands were polymorphic. Genetic similarity coefficients within the isolates were among 0.45 - 0.93, there existed a low degree of homogeneity between most of them. When all of polymorphic bands were analyzed by cluster analysis, 50 isolates were classified into 6 groups： Both RG Ⅰ and RG Ⅱ included 1 isolate, respectively, from Qinhuangdao and Xinjiang; RGⅢ and RGⅤ existed 2 isolates, respectively, from Qinghuangdao, Chengde and Langfang, Cangzhou; RGⅣ, It concluded 5 isolates which came from Tangshan, Shijiazhuang, Handan and Xinjiang areas; the others isolates belonged to RGVⅥ The result further demonstrated that there existed greater genetic differentiation among watermelon wilt isolates.