عنوان مقاله [English]
Chickpea is the third most important food legume in the world. Ascochyta blight is the most destructive disease of chickpea caused by the fungus Didymella rabiei. Identification of resistance sources in germplasm of chickpea is essential for breeding programs and management of disease. In order to investigate the effects of spore concentration and virulence severity of isolate on intensity of ascochyta blight in chickpea genotypes, a factorial experiment was conducted based on completely randomized design with three replications. Effect of two isolates (A3: moderately virulent & A6: highly virulent) and different spore concentrations (105, 2 × 105, 5 × 105 spores ml-1) were investigated on disease rate of 20 genotypes. Results showed that disease scale and its severity were affected by spore concentration, virulence severity of isolates and chickpea genotypes and there was significant difference between genotypes, isolates and spore concentrations. The disease severity increased with spore concentration from 2 × 105 to 5 × 105 spores ml-1 for resistant lines including, ILC 202, ILC72, ILC3279, ICC3996 and ICC12004, while the susceptible lines were affected by all of the conidial concentrations. The chickpea differential lines including ILC202, ILC72, ILC3279, ICC3996 and ICC12004 were resistant to all of the conidial concentrations of A3 (moderately virulent) while were susceptible to 2 × 105 spores ml-1 of A6 (highly virulent). The spore concentration of 2 × 105 spores ml-1 with A3 isolate developed the most discrimination between chickpea genotypes on the basis of mean disease scale. The obtained information can be used in breeding programs of chickpea and pathogenic diversity studies.