| Fusarium wilt of watermelon caused by Fusarium oxysporum f. sp. Niveum(Fon) is one of the most serious obstacles to reduce the yield and quality of watermelon. Four races of fusarium wilt of watermelon had been reported in the world. Race 1 was the predominant race type reported in China. Climate, soil type and the watermelon varieties are different in different watermelom planting provinces of China, which may result in the complex population diversity and different pathogenicity of fusarium wilt of watermelon pathogen in China.Biological characteristics, physiological races, genetic diversity and carbendazim resistance of fusarium wilt of watermelon pathogens from multiple regions of Chian were conducted in the study. The aim was to help to develop more effective prevention strategies for watermelon wilt disease control. The influence of different Environent conditions on the growth rate and sporulation of watermelon Fusarium wilt pathogens isolated from Hebei, Hainan and Shanghai were determined. The results show that:(1)29 strains isolated from infected watermelon plant were identified by host identification method. Among fusarium wilt of watermelon races, race 0, accounted for 10.34%; race 1, accounted for 58.62%, was the main physiological race; race 2, accounted for 10.34%.(2)To sequence and analyze 32 Fusarium oxysporum and two alien species by translation elongation factor EF-1α gene. The results showed that the Fusarium proliferatum〠Fusarium moniliforme and Fusarium oxysporum were divided into two groups with EF-1 alpha gene. The strain Fusarium oxysporum f. sp. cubense Fo-cubense and strain Fusarium oxysporum f. sp. lupinus Fo-Ha N-28 were separated to two branches, but they couldn’t be separated from the Fusarium oxysporum f. sp. niveum. The strong pathogenicity races of race 1 of small and race 2 clustered into one group and the weak pathogenicity races of race 0 and strains which could not be identified its physiological race clustered into one group in the remaining 32 isolates of watermelon specialization.(3)By tested effect of sugar and nitrogen on the mycelial growth and spore germination of fusarium wilt of watermelon, which their pathogenicity were different. It was found that the carbon sources had no significant effect on the rate of mycelial growth, the fungal mycelium grew better with peptone as nitrogen sources, glucose, starch, and lactose as carbon source could significantly increased the amount of sporulation of Fusarium oxysporum, sodium nitrate, yeast powder and peptone were significantly increased sporulation of fusarium wilt of watermelon pathogen. By inoculated spore suspension 1 x 105 spores / g soil of fusarium wilt of watermelon on the susceptible watermelon Jingyu 2, we found that the fusarium wilt of watermelon pathogen pathogenicity was significantly enhanced by glucose as carbon source culture and yeast powder and peptone as nitrogen sources.(4)The sensitivity of 146 watermelon wilt to carbendazim(MBC) were monitored. The results showed that the EC50 value of tested strains to MBC was 0.099mg/L-1.2384mg/L, the sensitivity of the frequency distribution of all strains were normally distributed, raised the average EC50 values(0.6002 ± 0.2586) mg/L as fusarium wilt of watermelon pathogen sensitive baseline to MBC. Compared the sensitivity of fusarium wilt of watermelon pathogen to MBC in the different regions, we found that there was no significant difference between the sensitivity of the strains to MBC and regions. Cluster analysis of sensitivity of watermelon fusarium wilt of watermelon pathogen to MBC in different regions showed that the sensitivity distribution of the strains to MBC was not relevant with region. Compared the sensitivity to MBC of the strains from Hebeiã€Henan and Fujian provincein, it was found that there was no significant difference between the sensitivity to MBC and year when strains collected. |
