Genetic diversity in population of Gaeumannomyces graminis var. tritici sampled from Kermanshah province

Take-all disease caused by the fungus Gaeumannomyces graminis (Sacc.) Arx & Oliver var. tritici Walker is the most devastating root disease of cereals throughout the world and it has been reported from different regions of Iran including Kermanshah province. During 2010-2011, diseased samples showing white head were collected from more than 300 wheat and barley fields visited in various parts of Kermanshah province. The pathogen were recovered from diseased samples collected from 139 fields representing prevalence of take all disease in nearly half (45 percent) of visited farms. Based on geographical distribution, ninety seven isolates of G. graminis were selected for further investigation. Two sets of primer pairs (NS5: GGT-RP and NS5: GGA-RP) were used to confirm identification and differentiation of the isolates. Eighty four out of 97 isolates produced 410 bp fragments when genomic DNAs were amplified with primer pair (NS5: GGT-RP) and 400 bp fragments with primer pair (NS5: GGA-RP) confirming the identification of the isolates as G. graminis var. tritici.But, 13 isolates did not amplify any bands. To study the genetic diversity of isolates of G. graminis var. tritici, 54 isolates were selected according to their geographical origins. Genetic diversity of selected isolates was studied using ISSR markers. Tenoutof 20 ISSR primers with high polymorphism and reproducibility were selected for further studies. Cluster analysis of DNA fingerprint profiles at the best cut off point divided the isolates into three groups; but there was no clear relationship between molecular cluster grouping and geographical distribution. The results showed that ISSR marker is an appropriate marker for genetic diversity studies in isolates of G. graminis var. tritici