1Departmant of Plant Pathology, Faculty of Agriculture, University of Birjand, Birjand, Iran
2Departmant of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
3National Plant Gene-Bank, Seed and Plant Improvement Institute, Karaj, Iran
4Plant Pest and Disease Research Institute, Plant Pathology Dept, Tehran, Iran
5Agriculture University, Birjand Branch, Islamic Azad University, Birjand, Iran
Objective: The aim of this study was to estimate genetic variability and phonetic relationships of 50 isolates of P. sojae from Iran. Methods: During 2005–2007, 142 isolates of Phytophthora sojae were collected from soil samples and diseased soybean plants from Lorestan, Mazandaran, Golestan and Ardabil provinces. Races of the isolates were determined. DNA of P. sojae fifty isolates was amplified with 20 RAPD and 5 ISSR primers. Results: Five primers amplified 77 fragments, of which 20 were polymorphic, indicating low variability. RAPD and ISSR primers clustered isolates into three distinct groups at 85% similarity. Genetic diversity among isolates detected intra specific variability even among isolates of the same geographic origin. There is no correlation between races, geographical distribution, and molecular markers.