Z. Noruzi, S. A. Moosavi, M. Darvishnia, N. Azadbakht, F. Fayazi

Abstract. The polymorphism and similarity relationships among 50 mating–type isolates of Ustilago maydis collected from Lorestan Province were determined with random amplified polymorphic DNA(RAPD). These fungal isolates were collected from 4 corn lines. Then DNA was extracted from haploid sporidiums using polymerase chains reaction (PCR) and specific primers, the genome of fungus were examined. Molecular studies of RAPD markers by using 10- primer 10 –nucleotide random primers were used. The highest multiples are established by primer opo1 with 16 bands in isolates and the lowest ones are related to opo 3 primer with 6 bands in isolates. Bands created the primers opo5 a 900 based pair band in 36 isolates and there was a separated model that isolate with other isolates were distinct. The primeres opo9 a 1000 base pairs band into clear 52 isolates as well as a 1000 base pairs band in isolates 52 and 51 can create and cause the rise of large difference between these two isolates with other isolates were. The results of analysis of data obtained by RAPD markers indicate the presence of genetic diversity in different populations of common smut of corn isolates. In this study according of the biggest amplitude slice different isolates of common smut of corn is divided into 8 groups of 52 and 51 each in a distinct cluster. The range of genetic similarity between isolates is from zero to 0.88 percent. The lowest genetic approximate amplitude was 51 with 23, 25, 26 isolates and the highest one was between isolates 33 and 32. Correlation Coefficient value of 0.83 was a good fit, which indicates the data was suitable matching to the dandrogram. Results also showed that the geographical distribution has no effect on genetic diversity