Determination of genetic variability of Fusarium oxysporum f.sp. melonis isolates in Khorassan Razavi province By AFLP molecular marker

Fusarium wilt of melon is one of the most common and widespread disease of this crop in the world and specially Iran. This investigation was carried out to determine genetic variation of Fusarium oxysporum f. sp. melonis in Khorassan Razavi province. For this purpose 52 samples were collected from main melon cultivation region of Khorassan Razavi. After purification and identification of isolates، molecular analysis was performed. From all sampled isolates only 35 based on their geographical origin and pathogenicity for molecular analysis were selected. After DNA extraction، genetic variation based on AFLP markers، on 6. 5%polyacryl amide gel electrophoresis and analysis by NTSYS software was done. Results showed at 63% similarity level، all isolates were placed in 6 AFLP groups A، B، C، D، E، F and two groups with just single member. Cluster analysis also showed there was significant genetic variation among F. oxysporum f. sp. melonis isolates in Khorassan Razavi. On the other hand according to cluster analysis it was determined that there was no specific correlation between geographical regions and AFLP genotypic groups. Also، no identified specific correlation was found between pathogenicity groups and isolated point of plant with AFLP groups.