Analysis Of Population Diversity Of Blumeria Graminis F.sp. Tritici And Resistance Genes Of Wheat Cultivars Of Lines To Wheat Powdery Mildew

Powdery mildew samples of wheat were collected from Guizhou province in April 2004.The pathogens from different samples were studied by conventional morphologyical test and RAPD molecular analysis.The relationship between the two methods was initially explored.The resistanc -e of wheat cultivars to powdery mildew was analysised.1. Physiologic race and population virulence of Blumeria graminis f.sp. tritici at Guizhou Province were tested on detached wheat leaves.(1) 63 isolates of Blumeria graminis f.sp. tritici were collected and 26 physiologic races were obtained, race 315 was dominant race with frequency of 17.4% ,while race 311 was subdominant race.(2) Isolates V1,VEra,V3b,V4b,V4+8,V4+2x,V5, V7,V8,V1+2+9,V11 showed the virulence frequency above 50%,while V2,V6 between 25%~50 %;V2+4,V2+6,V2+6+?,V2+6+1,VXBD,V17,V18,V19,V21 under 25%;V12 showed it indicated 0%.Blumeria graminis f.sp. tritici from Guizhou province has a high gene virulence frequency and Pm2+4,Pm2+6+?,Pm21,Pm2+6+l,Pml2,Pm17,Pm18,Pm19,provided applicable value in breedin-g-2. Analyses of resistance genes of wheat cultivars or lines to powdery mildew:Forty wheat cultivars or lines were inoculated with twenty-one different isolates of powdery mildew,and resistant spectra of the isolated were compared.The results showed that Guinong-5,Guinong-7 carry Pm21,Qianyu-6 carry Pm4+8,etl.The spectra of 20 cultivars or lines are different from those of all with unknown genes.and seven cultivars or lines are susceptible to all twenty-one isolates of wheat powdery mildew.3. 24 isolates were tested in RAPD analysis.(l)56 random primers were used to amplify and 30 primers were initial selected. 39 loci were obtained through amplication with 5 primers,71.8% with 28 polymorphic loci were polymorphic frequence,Loci focused on 300~2500bp,RAPD showed similarity among the isolates but also difference,which showed the genetic diversity in the population of Blumeria graminis f.sp. tritici. (2)Clustering analysis showed that the same field collected together.24 isolates were tested with the genetic distance from 0.1719~0.8044.(3) Clustering analysis showed that the same physiologic race collected untogether, uncorresponding relation between virulence and RAPD markers was presented of isolates of Blumeria graminis f.sp. tritici. Compared with traditional morphological and molecular marker classification,there was a little dissimilar.