The Study On Germination Infection And Genetic Differentiation Of Plasmopara Viticola In Xinjiang

Grape downy mildew is a kind of disease which has strict requirements on environmental conditions,and it is an important disease threatening grape production.In recent years,due to the growing area of susceptible varieties in Xinjiang,so that the disease is increasing.Grape downy mildew resistance breeding is the most effective means of controlling the disease,not only can reduce the yield loss,but also reduce the use of chemical pesticides,reduce environmental pollution.This research mainly includes 3 aspects:firstly,study the climate factor effecton the germination and survival of sporangia,in order to reveal the disease more stringent climate conditions;secondly,grape downy mildew resistant and susceptible varieties were observed in the infection process of the organization,in order to reveal the infection after infection of resistant and susceptible varieties,similarities and differences process;thirdly,analysis of different regions of Xinjiang grape downy mildew Pathogenic Differentiation and genetic diversity,in order to reveal the main Xinjiang grape downy mildew interspecific diffe-rence in pathogenicity and genetic diversity,provide the basis for prevention and control of varieties and breeding.The results are as follows:1.Sporangia could germinate and release zoospores only in water,the optimal germination temperature is 18-22 ℃.The sporangium survival with temperature,humidity,light has close relationship,inoculated with leaf discs,withered sporangia still disease,can not be used as a marker of dry sporangium sporangium death.2.The grape downy mildew(Plasmopara viticola)in the process of infection of susceptible varieties and the resistant cultivar ’Red Globe’ ’BEIMEI’,found two varieties from inoculation to symptom are basically the same,but the time out of the sporangium stomata,extending sporangiophore stomatal ratio than the ’Red Globe’ ’BEIMEI’;’BEIMEI’ on the mycelial growth speed is slow,the late hypha growth rate is relatively small.Bacteria in the ’Red Globe’ on the latent period of 4 d,and in the ’BEIMEI’ 5 d.There are the frequency difference between the two varieties produced haustoria in primary hyphae and long mycelial stage.3.The results of the pathogenicity test showed: From different regions of Xinjiang were within the species of pathogenic differentiation phenomenon,on the basis of the pathogenic differential host capacity of different isolates can be divided into 3 classes: strong,medium and weak,which strongly pathogenic isolates were the dominant strains,and interspecific pathogenicity differentiationand geographic origin of isolates tested are independent.4.The results of SSR markers showed: The phenomenon of genetic variation between strains,and genetic relationship between strains are close,the similarity coefficient was 0.93,the 48 strains were clustered into 4 categories,and the genetic differentiation and geographic distribution has a certain relevance.