中文摘要：

为了明确我国香蕉主要种植区香蕉枯萎病菌（n“甜iMmoxysporumf．sp．cubense，FOC）的致病力及其遗传多态性，本研究采用对寄主鉴定和RAPD技术分析来自海南、广西、广东、福建、云南的FOC生理小种、致病力分化及遗传多态性。结合巴西蕉和粉蕉鉴定与RAPD技术，与香蕉枯萎病菌l号（FOCl）和4号生理小种（FOC4）对比．55个FOC菌株中．有28个菌株属于1号生理小种，海南10个、广西8个、广东4个、福建4个、云南2个；27个菌株属于4号生理小种，海南20个、广西4个、广东1个、福建1个、云南1个。强致病力菌株有23个菌株，中致病力菌株有15个．弱致病力菌株有17个；通过遗传多态性分析，9条引物PCR扩增供试菌株，共扩增出136条谱带，其中多态性的条带有126条．多态性位点频率为93．4％，在遗传阈值为0．68时，55个供试菌株与FOCl和FOC4划分为4个RAPD菌群，除1号生理小种BF26菌株单独形成Ⅳ菌群外，4号生理小种和其余1号生理小种均末单独形成菌群，Ⅰ、Ⅱ、Ⅲ菌群同时含有1号和4号生理小种。因此，我国香蕉种植区香蕉枯萎病菌仍以1号和4号生理小种为主．但是生理小种的遗传分化在分子水平上趋于复杂化，香蕉枯萎病菌群体具有丰富的多态性．其致病力的强弱和菌株遗传关系无直接的相关性，跟地理分布也没有相关性，香蕉枯萎病菌的遗传多态性可能更多依赖其寄主。这些结果为香蕉的抗病育种、品种的合理布局以及香蕉枯萎病的综合防治提供理论依据。

英文摘要：

In order to charily the pathogenicity and genetic polymorphisms of Fusarium oxysporum f. sp. cubene （FOC）,which caused banana fusarium wilt, in the main banana growing areas of China, the race type,pathogenicity differentiation and genetic polymorphism of 55 FOC isolates from Hainan,Guangxi, Guangdong ,Fujian and Yunnan provinces, were analyzed by Identification host and Random Amplified Polymorphic DNA （RAPD） methods.According to the results of Brazil banana and Fenjiao banana identification, and RAPD analysis, compared with the identified FOC race 1 （FOC1） and FOC race 4 （FOC4）,28 of 55 FOC isolates were trice 1, such as 10 from Hainan, 8 from Guangxi, 4 from Guangdong, 4 from Fujian, and 2 from Yunnan; 27 of 55 FOC isolates were race 4, such as 20 from Hainan, 4 from Guangxi, 1 from Guangdong, 1 from Fujian, and 1 from Yunnan. In 55 FOC isolates, there was 23 strong pathogenicity isolates,15 moderate pathogenicity isolates, and 17 weak pathogenicity isolates. DNA of the tested isolates were amplified with 9 candidated primers by PCR, and produced 136 bands, including 126 plolymorphic bands, and polymorphic loci frequency of 93.4%. Based RAPD result, in the genetic threshold of 0.68, 55 FOC isolates, FOC1 and FOC4 were divided into 4 RAPD groups. In addition to race 1 BF26 isolate separately formed 1V group, all race 4 isolates or the rest of race 1 isolates were not formed one group alone. I , 1I and Ill groups contain both race 1 and race 4 respectively. Therefore, race type of FOC in China banana plantation still is race 1 and race 4. However, the genetic differentiation of FOC races tends to be complex at the molecular level, the group of FOC has a wea｜th of polymorphism, the pathogenicity of FOC isolates is no direct correlation with its genetic relationship, and no correlation with its geographical distribution, genetic polymorphisms of FOC may be more dependent on their host. These results may provide the theoretic foundation for disease-resistance breeding, rational distribution of var