Pathogen And Virulence Analysis Of Wheat Sharp Eyespot And Wheat Stem Base Rot

Wheat sharp eyespot is one of the most important diseases in the north latitude33°regions of China. One hundred and fifty-seven Rhizoctonia isolates were obtained from different areas of Jiangsu, Anhui, Henan and Hubei province in2008and2009. Identification results showed, among these isolates,150isolates were R. cerealis with percentage of95.54%, and7isolates were Rhizoctonia solani with percentage of4.46%. All R. cerealis isolates were in AG-D anastomosis group. Among the7isolates of R. solani, based on anastomosis and blast of their ITS sequences, one isolate was in AG5anastomosis group, and three isolates were in AG11and3isolates were in AG-1-1B, respectively. The virulence of111isolates was tested with artificial inoculation method in greenhouse. The results showed that virulence of these isolates was different significantly. The virulence of R. cerealis isolates was higher than that of R. solani isolates. No significant difference was observed between two R. cerealis AG-D groups with different anastomosis frequency. The virulence of isolates from4provinces was not significantly different. The virulence of isolates to3wheat cultivars was significantly different, and it was the highest to CI12633and the lowest to Shan229.Pathogens causing wheat stem base rot were complicated. One hundred and ten isolates were isolated from different areas of Jiangsu, Anhui, Henan, Hubei, Hebei and Sichuan province in2008and2009. Identification results showed, among these isolates,41isolates were Bipolaris sorokiniana,33isolates were Fusarium spp.,12isolates were Epicoccum spp., and24isolates were Microdochium nivale. The virulence of4pathogens was evaluated with artificial inoculation method. The results showed that virulence of4pathogens was different, the virulence of Bipolaris sorokiniana isolates was higher than that of other3pathogens.SSR primers developed in AG-1andAG-3were used in this study, but these primers were no avail in AG-D;(AC)10、(AG)10、(AT)10、(GTG)6and (GCT)5were selected to developed SSR primers by ISSR (Inter-simple Sequence Repeat)-PCR method. Twenty seven pairs primers IP1and nested primers IP2were designed based on (AG)10, then1pair of SSR primer was obtained,12R. cerealis obtained polymorphism fragment between300to500bp based on this pair of primer.