| In order to charify 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 race 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 Ⅳgroup, all race 4 isolates or the rest of race 1 isolates were not formed one group alone. Ⅰ,Ⅱ and Ⅲgroups 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 wealth 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 variety and integrated control of banana fusarium wilt.