STUDY OF THE GENETIC DIVERSITY OF Monosporascuse cannonballus ISOLATES CAUSAL AGENT OF ROOT ROT AND VINE DECLINE OF MUSKMELON IN IRAN USING REP-PCR MARKER

Root rot and vine decline of cantaloupe and muskmelon plants is an economically important disease in Iran caused by Monosporascus cannonballus. Regarding the recent detection of the disease in Iran, genetic diversity of the causal agent need further research. In this study, isolates of M. cannonballus were collected from Esfahan, Yazd, Tehran, Fars, Semnan, Markazi, Ghazvin, SistanBaluchestan and Khorasan Razavi provinces. Genetic diversity between 50 isolates of the pathogen was studied using Rep-PCR markers; Box and ERIC. Reproducible fragments were between 100 and 1500bp and the genetic diversity amongst the isolates calculated 0.32. There was a correlation between genetic diversity, host and geographic origin of the isolates. M. cannonballus isolates were placed in two groups based on their host plant. Cluster analysis using UPGMA method and Dice's coefficient revealed 100% similarity between some isolates collected from different regions. There was a correlation between colony morphology in the culture media and genetic diversity where at %80 similarity level the isolates were placed in three different groups. The discriminatory power of rep-PCR was high, indicating that rep-PCR is a rapid, effective marker for genotyping M. cannonballus isolates.