Investigation of genetic diversity of sugar beet isolates of Pythium aphanidermatum Fitzp using Inter-simple sequence repeat amplification marker(ISSR)

Root rot disease is one of the most important sugar beet disease in Iran that infected by Pythium aphanidermatum Fitzp. For studying genetic diversity of this pathogen, 10-20 samples were collected from sugar beet fields in eight provinces of Iran. After purification, isolates were identified based on morphological characteristics of sexual and asexual organs and 19 isolates were selected in order to molecular diversity studies. ISSR analysis of all isolates was performed using eight primers. Results of phylogenetic tree of primers based on UPGMA method and Jacards similarity coefficient, were categorized isolates into five groups (64% similarity). The results of analysis of growth rate in two temperatures at 26±2Cº and 29±2Cº, by MSTATC and MVSP, was categorized isolates in to two groups with low growth and high growth rate. Analysis of morphological and molecular variation were indicated that isolates of this eight geographical regions have genetic relationship but there isnt necessary relationship between growth rate of isolate and their geographical distribution.