Genetic Diversity Of Blumeria Graminis F.sp.tritici Populations In Part Of Wheat Growing Areas In China

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is a worldwide wheat disease. Analysis of genetic diversity of Blumeria graminis f. sp. tritici, based on population genetics, can reveal the population structure and virulence evolution in theory, meanwhile plays an important guiding role in practice, such as screening and appraisal of resistant resources, distribution of resistant genes, strategy making of controlling the disease and so on.Thirty-five differential lines possessing known wheat powdery mildew resistant genes were used in virulence analysis for the population consisted of 134 isolates collected from Sichuan, Beijing, Hebei and Gansu. The results showed the population had higher virulent frequencies (>50%) among resistant genes Pm1, Pm3a, Pm3b, Pm3c, Pm3d, Pm3e, Pm5, Pm6, Pm7, Pm8, Pm17, Pm19 but lower value (<30%) among Pm5(Mli), Pm12, Pm13, Pm16, Pm18, Pm21, Pm2+6, Pm2+MLD and Pm1+2+9, indicating the latter can be well used in breeding resistant wheat vairieties.Clustering result based on the unweighted pair-group method with arithmetic averages (UPGMA) by NTsys-2.10e indicated virulence similarity coefficient of 134 strains was between 0.66 and 1.00, which means small difference on virulent genes contained in Blumeria graminis f. sp. tritici. And virulence difference has some relativity with region resource.In total, 134 strains were analyzed by ISSR technology, 6 from 50 primers were effective to produce DNA polymorphic bands. A total of 93 ISSR bands were obtained, and 56 of them, covering 60.22%, showed polymorphism. Dendrogram analysis using UPGMA by NTsys-2.10e showed genetic diversity of Blumeria graminis f. sp. tritici, were correlated to groups defined by geographical origin. Parameters of genetic diversity calculated by PopGene32 indicated that the genetic diversity level of Blumeria graminis f. sp. tritici in China was not high.Clustering results of 134 isolates and population from four regions showed no obvious difference by NTsys-2.10e, Popgene32, MEGA4 and TreeView, and got the same conclusion basically, which means these soft wares can be used in genetic diversity analysis of Blumeria graminis f. sp. tritici.Through polymorphism comparison, we found some relativity between virulence polymorphism and genetic diversity, however, its relationship is more complicated than linear relation.