virulence and molecular diversity in puccinia striiformis f.sp. tritici from iran

abstract to study virulence and molecular polymorphism variation of puccinia striiformis westend. f.sp.tritici eriks. (yellow rust disease agent) in iran, 86 isolates were collected from all around the country. race determination was carried out according to johnson et al. (1972) method. in addition, isolates were analyzed by aflp method by four primer combinations . according to the results of race determination, 35 physiological races were identified. race 178e0a- with 7 members was the most frequent followed by race 64e241a+ with 5 members. virulence was not detected on the commercial cultivars having yr1(except for 4 isolates), yr3, and yr5 genes. virulence for yr2, yr24, yr7 and yra was detected in all around the country. in average for every primer combination 78 bands were recorded that 30 percent of them were polymorphic. analysis of data by ntsys software grouped all isolates in 9 main groups as a, b, c, d, e, f, g, h and i, and 10 single isolates groups in 77% similarity coefficient. there was significant relationship between geographic origins and aflp fingerprinting groups. however there were not certain relationship between races and these groups. genetic similarity between most of populations and west/northwest population ( contain ilam, hamadan, kermanshah and ardebil provinces) was more than 65% . this similarity may be because of sudanian and mediteranian flows in transferring of spors from northwest of iran to north and southwest of iran and concluded to a gene flow.