Study of genetic diversity of Septoria tritici isolates from wheat fields in Ilam province using SSR marker

Septoria tritici blotch (STB) caused by Septoria tritici is one of the most important wheat diseases in Ilam Province. In order to determine genetic diversity of pathogen, 44 samples were collected from wheat fields of different regions in Ilam province. Molecular test was carried out with a set of five pairs of SSR primers after purification and identification of isolates. The SSR primers amplified a total 22 alleles among isolates. The average of allele number was 4.4 per each primer. Genetic diversity of the populations ranged from 0.138 to 0.166 with an average of 0.154. Cluster analysis based on UPGMA method and Dice coefficient, divided the isolates into 18 groups at 0.54% similarity level. Result of AMOVA showed that 98% of genetic diversity was in relation to isolates and only 2% was in related to different geographical regions. Therefore there is the high genetic similarity between isolates from different geographic regions. High genetic similarity can be attributed to emigration of gene or genotype as a result of various factors.