Genetic structure of Colletotrichum gloeosporioides s.l. populations, the causal agent of citrus anthracnose in North of Iran

Citrus dieback and postbloom fruit drop caused by Colletotrichum gloeosporioides are common diseases of citrus trees in North of Iran. According to increasing of disease damage in recent years, which can be due to the genetical alteration of pathogen, genetic structure of the fungus population in North of Iran was studied. So, four citrus orchards in Rahim Abad (Guilan), Ramsar, Sari and Gorgan were surveyed and. symptomatic tissues were sampled. After identification of fungal Isolates, DNA fingerprinting for144 Isolates were done by seven ISSR markers and PCR method. Acording to cluster analyses by UPGMA method and Jacard coeficient, thirteen groups were found. The mean of gene and genotype diversities across all populations were 0.33 and 0.49 respectively. There were low genetic differentiation (0.127) among populations and high gene flow (3.437) proved the low genetic differentiation. Maximum genetic identity observed between Guilan and Gorgan and the minimum observed between Ramsar and Sari populations. Distance between Rahim Abad and Ramsar is less than between Ramsar and Sari. So, genetic distance between Guilan and Ramsar and between Ramsar and Sari populations correlated to their geographical distance, but it was irregular for Guilan and Gorgan isolates. According to this study C. gloeosporioides populations derived from citrus orchards in North of Iran have genetic diversity and low genetic differentiation and Genetic distance among populations confirm the high gene flow among them.