Identification of Genetic Diversity in the Ascochyta Blight Pathogen of Chickpea [Ascochyta rabiei (Pass.) Lab.] Using RAPD Markers

The poor information available on variation of Ascochyta blight fungus is the most important factor limiting chickpea breeding programs for resistance to blight disease. In this study, efforts were made to detect genetic variation of the pathogen in Iran. The RAPD marker was employed to evaluate 26 isolates collected from 16 provinces. Twelve random primers were used to analyze genomic DNA of the isolates. Only ten primers showed polymorphism among isolates. Primer OPK-01 defined the highest number of polymorphism and primer OPK-09 confirmed relatively low degree of polymorphism. On the basis of this molecular marker, the estimated genetic diversity index was 98% and the pair-wise genetic distance of the isolates varied from 0.16 to 0.61. The least genetic distance belonged to isolates 20 and 22 from Qazvin and Golestan while the highest distance belonged to isolates 26 and 12 from Mazandaran and Markazi. The phylogenic tree was constructed by cluster analysis and all the isolates grouped to 22 genetic clusters at the 90% similarity level. The genetic groups were named from A to V and their distribution in Iran was determined. The results revealed that genetic variation among Iranian population of the pathogen is very high, and further that RAPD is a vigorous tool for genomic analysis of Ascochyta rabiei.