RAPD Analysis Of Wheat Powdery Mildew(Blumeria Graminis F.sp.tritici) And Phylogenetic Study Of Powder Y Mildews From Different Hosts

Wheat powdery mildew samples were collected from Zhangye,Wuwei,Lanzhou, Dingxi of Gansu province in July–September,2003. Conventional morphologyical test and RAPD molecular analysis were studied .The relationship between them was initially explored,too.1. Physiologic race and population virulence of Blumeria graminis f.sp tritici in the mid-west of Gansu Province were tested on detached wheat leaves .Results:(1)36 isolates of Blumeria graminis f.sp tritici were collected and 20 physiologic race were obtained, among them race 015 was dominant race with frequency of 16.7% while 077 was subdominant race.(2) Isolates V Era,V8,V1,V3c,V3f showed the highest virulence frequency above 70%,while V2,MID,V20,V21,V4b,V4 below 16.7%. It indicated Blumeria graminis f.sp tritici from mid-west of Gansu province has a high gene virulence frequency and Pm2+MID, Pm20, Pm21, Pm4b, Pm4 provided applicable value in breeding. It also indicated there was difference in population virulence structure and virulence frequence of Blumeria graminis f.sp tritici between regions.2. 16 physiologic race (20 isolates )were tested in RAPD analysis .Results:(1) 60 random primers were used to amplify and 35 primers were initinal selected. 81 loci were obtained through amplication with 9 primers ,66.7％with 54 polymorphic loci were polymorphic frequence.Loci focused on 500-2000 bp and polymorphic loci from different primers had large difference. It indicated there has heredity differentiateon in population. (2) Clustering analysis showed that populations from Wuwei had obvious diversity which collected from Tianzhu mountain and displayed light infection; Electrophoretic patterns showed that isolate 16 from Wuwei has high polymorphic, a band of about 2.8kb was obtained with primer S153, this band maybe associated with invirulence gene or with a gene determining an unknown phenotype. (3) Polymorphic frequence was 96.3% using PopGene32 and higher than result with Shanweixing(1995) method.The SPSS software was in accordance with the PopGene32 software statistics result basicly, therefore in analysis of wheat powdery mildew RAPD results, two kinds of methods are all viable. 3. Phylogeny of powdery mildews collected from different hosts were studied with RAPD, Results:(1)45 loci of 5 primers were obtained through PCR amplication, Polymorphic frequence was 84%, which was higher than different isolates of wheat powdery mildew.(2)Clustering analysis showed that there were two nodes in 12 species.Heredity relationship was compared with traditional morphological classification,but there was a little dissimilar in position of some species .It indicated morphological study is required to study phylogeny of powdery mildews with other methods except molecular marker in order to get more accurate results.