Study on Virulence Differences of Cucumber Downy Mildew in Different Areas

For the selection of resistant cucumber varieties,studied the length and width of sporangia from all eight provinces of the 18 strains of cucumber downy mildew,in order to determine the differences of cucumber downy mildew between regions.The results showed that 18 strains of cucumber downy mildew sporangia had differences,between strains from the same city was no significant difference,and from the 10 tested cucumber cultivars were screened out seven cultivars of reactive different and resistant and susceptible disease to different pathogenic strains,but preliminary screening for cucumber downy mildew physiological small differential host differentiation,by using differential host will 18 strains was divided into 12 pathogenic types.