Study On Identification Of Pathogen In Potato Fusarium Wilt And Genetic Diversity Of Fusarium Oxysporum

In recent years, potato Fusarium wilt occured in many potato planting areas of the China and became more and more serious, which was an important factor induced yield loss in potato production. Potato wilt was a disease caused by Fusarium spp., in different regions there were different pathogenic species. It was difficult to control. In this paper, the potato wilt plants were collected from all over the country and isolated. The isolates identification, pathogenicity, biological characteristics and genetic diversity were studied. The results were as following:The isolates were identified by morphological and molecular characteristics. In results, the pathogen of potato wilt were identified as F. oxysporum, F. tricinctum and F. solani in Inner Mongolia, Shanxi, Ningxia, Guangdong. Ganshu and other region. The F. tricinctum was founded only in Inner Mongolia. The largest proportion was F. oxysporum, and it was the main specie.The pathogenicity of pathogen was tested and showed F. oxysporum was the strongest, F. solani was the second, and F. tricinctum was weak. The pathogenicity of pathogen was not related with geographic origin.The biological characteristics were tested. In results, for F. oxysporum the optimal temperature was 25℃, pH was 7, media were PDA, PSA and Bilais. carbon source were starch, maltose and nitrogen source was peptone; For F. tricinctum the optimal temperature was 20℃, pH was 7, media were cornmeal agar and oatmeal medium, carbon source and nitrogen source were starch and carbamide; For F. solani the optimal temperature was 30℃, pH was 7, medium was PSA, carbon source were glucose, sucrose and nitrogen source was nitre.The genetic diversity was analied and showed:A total of 126 bands were amplified with 17 selected ISSR primers,117 of which were polymorphic and accounted for 92.9% among the amplified fragments. The analysis of dendrograms showed that genetic similarity coefficient of 21 isolates was 0.61 to 0.89, and all the strains could be distinguished at 0.89, which showed certain relation between the Fusarium differentiation and the geographic origin.