Genetic diversity of Rhynchosporium secalis isolates causal agent of barley scald in Ilam province

One of the most important diseases of barley is scald in the world. In order to determine genetic diversity of Rhynchosporium secalis isolates، barley plants with yellowish brown spots with brown margin، especially on leaves and stems were collected from different regions of Ilam province including: Ilam، Asemanabad، Srableh، Shabab، Ivan and Sirvan. 47 isolates obtained from infected samples using potato dextrose agar for the purposes of this study. To study the genetic diversity of the isolates، microsatellite markers were used. A set of five microsatellite primer pairs revealed a total of 42 alleles in R. secalis isolates in all isolates. The number of alleles varied from 7 to 12 for each marker. The number of marker index (MI) in all primers varied from 1. 8 to 6. 7 and genetic similarity based on Dice coefficient was zero to one. Phonogram revealed 16 distinct groups in 0. 54 similarity distance، but based on neighbor joining 17 groups were determined. Knowledge of genetic diversity in R. secalis provides different levels of information which is important in the management of germplasm resources. Results from this study will be useful in breeding for barley resistant cultivars and developing necessary quarantine regulations.