Pathogen Identification And Pathogenicity Difference Analysis Of Linseed Wilt In Shanxi Province

Linseed wilt was an important disease affecting the yield and quality of linseed.It occures seriously in the producing areas of linseed in Ningwu and Kelan,Shanxi Province,causing serious economic losses to local growers.Therefore,it is of great significance to study this disease.In this study,morphological and molecular biological identification methods were used to identify the pathogens of the diseased linseed wilt plants collected from Ningwu and Kelan,Shanxi Province.Pathogenicity of the isolated pathogens were also tested to analyze the differences in pathogenicity.Furthermore,the constitution of SIX genes in different formae speciales of Fusarium oxysporum were preliminarily analyzed.The main results were as follows:1.Morphological and molecular identification methods were applied to identify the species of linseed wilt pathogens in Ningwu and Kelan,Shanxi Province.The results showed that 28 strains of Fusarium were isolated from 40 diseased materials collected in the two places,and three types of Fusarium species had been identified including Fusarium oxysporum,Fusarium tricinctum,and Fusarium equiseti.Among them,Fusarium oxysporum had the highest isolation frequency of 92.9%,which was the dominant pathogen.Fusarium tricinctum and Fusarium equiseti had lower isolation frequencies of 3.6%,and only existed in the samples collected in Ningwu.2.The pathogenicity differences of different Fusarium oxysporum strains were tested through root-drenching method.The results showed that the pathogenicities of different strains to the resistant linseed variety Jinya No.7 and the susceptible linseed variety Shanxi 29 Huang were significantly different.There is obvious pathogenic differentiation among the tested strains.The pathogenicity of F52 strain was the weakest,and F51 was the strongest.At the same time,the pathogenicity of the strains of different geographical sources and the strains of the same geographical source were also different.The pathogenicity of Fusarium oxysporum isolated in Ningwu was higher than that in Kelan.Among Fusarium oxysporum in Ningwu,the average incidence was 54.8%,and the average incidence of Fusarium oxysporum in Kelan was 49.1%.There were also significant differences in the disease resistance among different varieties.The average disease index of the resistant variety Jinya No.7 was between 11.1 and57.8,and the average disease index of the susceptible variety Shanxi 29 Huang was between 35.6 and 91.1.3.The PCR amplification method was used to study the constitution of SIX genes in different formae specieles of Fusarium oxysporum.The results showed that the SIX6 gene exist in F.oxysporum f.sp.cucumerinum,F.oxysporum f.sp.lycopersici,F.oxysporum f.sp.niveum and F.oxysporum f.sp.vasinfectum;the SIX7 gene is exist in F.oxysporum f.sp.cucumerinum,F.oxysporum f.sp.lycopersici,F.oxysporum f.sp.fabae,F.oxysporum f.sp.niveum and F.oxysporum f.sp.melonis;SIX8 gene is exist in Fusarium oxysporum.