Evaluation of chickpea resistance against some isolates of Ascochyta rabiei, the causal agent of ascochyta blight.

Ascochyta blight, incited by Ascochyta rabiei (Pass.) Lab., is one of the most important fungal diseases that has been shown to cause significant yield losses on chickpeas in Kermanshah province, Iran. One of the most effective and reliable methods of controlling the disease has been the use of resistant cultivars worldwide. This requires the identification of the physiological races of the fungus in the region in advance. In this regard, pathogenicity of 30 isolates of A. rabiei was determined using 10 differential chickpea varieties (mean of 1-9 degree of disease in three replications) under greenhouse conditions. In this respect, isolates fell into four groups, whereas based on infection type three groups were identified using cluster analysis. Disease resistance of four chickpea cultivars, Hashem, Jam, ILC-482 and Bivanij, were evaluated against isolates from each of three groups separately and in combination in the greenhouse and field conditions (with 4 replications). The experiment was repeated twice with three replications in greenhouse. Chickpea cultivars were sprayed with fungal spore suspension (2x10(5) spores/ml). Results showed that Jam and Bivanij cultivars were susceptible under greenhouse as well as field conditions. Hashem was tolerant to group I and susceptible to groups II and III and in the field. ILC-482 was tolerant to groups II and I and susceptible to group III and the combination of groups under greenhouse condition.