Identification of Pathotypes in Ascochyta rabiei (Pass.) Labr., the agent of Ascochyta blight in chickpea in provinces of Kermanshah and Ilam and resistance evaluation of chickpea cultivars and lines against disease

Ascochyta blight caused by Ascochyta rabiei Pass. (Labr.)is one of the greatest disease in chickpeathat cause total yield loss if the environmental conditions are favorable. The use of resistant cultivars is the most effective management strategy for ascochyta blight in chickpea. In our study, 24 different isolates of A. rabiei from plants infected by this disease were obtained in provinces of Kermanshah and Ilam and then isolated and purified. For evaluation of the morphological characteristics, discs of colonies of fungal isolates were sown in PDA, CDA, CSA and WA media. For pathotypes identification, the isolates were sporulated on differential chickpea cultivars by concentrations with 106 spores per ml. 41 genotypes and chickpea cultivars inoculated by three A. rabiei pathotype like pathogenicity method in greenhouse. The severity of the disease index is noted from 1 to 9, according to the scale of Jan and Wiese and 12 days later when the intensity of symptoms reached to 90 percent on susceptible cultivar. The results of our study revealed morphological and genetic diversity of the fungus. In this survey, three pathotypes identified in different districts of Kermanshah and Ilam, respectively. Pathotypes 1 of 13 of total isolates was the most widely distributed then, pathotype II with 6 isolates and pathotype III with 5 isolates were the least ones. The response of 41 cultivars against three pathotype of A. rabiei, Adel, Azad cultivar that have just been released by the Agricultural Research Institute of Dryland over the past few years together with advanced line of Flip 03-109C against the pathotype III showed moderately resistant response while other lines and cultivars were susceptible or highly susceptible. In total, lines of Flip51-87C, Flip03-119C, Flip04-13C and Flip04-10C showed resistant or moderately resistant response for pathotypes.