Resistance Evaluation Of Potato Germplasm Against To Phytophthora Infestans And Development Of SSR Primers Of Phytophthora Infestans

Potato is the fourth food crop in the world, which is behind rice, wheat and corn."International Year of the Potato(IYP)"was declared by the United Nations in 2008. and it has high-lighted the important position of potato in the global food system. The potato late blight was the most important diseases in potato production。In a variety of control methods, Planting resistant varieties was the most economical and effective way to control the disease. In this research, All of five aspects were study on the pathogen and host. which will provide a theoretical basis for resistant breeding and appropriate distribution of resistant varieties.1.Fifty-seven isolates of P. infestans collected from six provinces including Heilongjiang, Hebei, Fujian, Inner Mongolia, Yunnan and Sichuan were tested with a set of 11 potato clones of differential hosts containing single dominant resistant gene (R1 to R11). Total of 30 races were identified from 57 collected isolates, all of them were complex-races possessing at least two virulence genes and the majority showed five or more, with the frequence of 83%. In addition, there were three isolates called as"super virulence race"were found, one comes from Yunan, the other two comes from Sichuan which can overcome all known 11 resistant genes (R1 to R11).2.Total of 22 cultivated potatoes were tested by detached leaflets inoculation for identification and evaluation of different potato cultivars resiatance to P. infestans, The result show that both of cultivies kexin18 and kexin19 showed highly resistance to P.infestans, and the remaining 18 cultivars have different levels of resistance to the pathogen. Light, medium and high susceptible varieties were 27%, 55% and 9%, respectively.3.In total of 338 potato germplasm were introducted from the United States. 10 different physiological races of P.infestans were inoculated detached leaflets in vitro for resistance identification and evaluation.The result showed that 58 materials were resistant to the isolate of P. infestans. 54 materials in which were immune to all races of P. infestans and 4 wild germplasm showed high resistant, the remaining 280 materials were showed susceptible to the isolates of P.infestans, the germplasm materials which express light, medium and high were 14, 48 and 218,which account for 23.7%,1.8%,6.1%和95.6%, respectively. 4. The potato group of nine lines of 12 wild species of potato material used for sequenced, total of 53 ETS gene sequence used for constructed phylogenetic trees. The result showed that different species ETS sequence heterogeneity among clones, and suggest that there were different wild potato species of hybrid frequent events. We also found that the ETS gene phylogenetic tree was not related with the disease resistance.5. Based on the released genome sequence data of P. infestans, 10 SSR primers were designed for fliter primers of P. infestans, one good pair of specific SSR primers was got.