Genetic and Morphological Diversities in Sclerotinia sclerotiorum Isolates in Northern Parts of Iran

Sclerotinia sclerotiorum is the most important causal agent of stem rot diseases on the field crops in Iran. During 2006-2007, totally 65 isolates of the fungus were obtained from infected rapeseed, lettuce, bean, tomato, cucumber and wild sinapsis plants in various fields of North provinces in Iran. Genetically diversities between the isolates were investigated by PCR, using five microsatellite primer pairs and those divided to 9 groups with 25 clear polymorphic alleles. A high level of genetic diversity was observed about 67%, between the some isolates. By mycelial compatibility grouping tests, the isolates were settled into 39 groups that 26 MCGs were individual. Molecular and phenotypic analyses results of the most of isolates were similar; however the isolates in MCG1, MCG4 and MCG23 groups, with variable microsatellite haplotypes, were morphologically dissimilar. The results shown that there were possibly high rates of out crossing as well as evolutionary potential within population of the pathogen in different collecting locations. This is the first study in genetical variations of S. sclerotiorum populations in Iran.