Evaluation of resistance and enzyme production of faba bean cultivars against Alternaria leaf spot

Faba Bean (Vicia faba) is an important legume among cultivated plants and Alternaria leaf spot is a serious disease that causes broad damages and yield loss in Golestan and Mazandaran provinces. In current research, sampling was carried out from Mazandaran and Golestan provinces. Morphological and molecular surveys of the obtained isolates showed that they belong to A. alternata species. In order to evaluate resistance of nine Faba Bean cultivars against Alternaria leaf spot, area under disease progress curve (AUDPC) were calculated in greenhouse condition. In addition, variation of some resistance related enzymes between resistant and susceptible lines were tested at different time intervals after inoculation. Statistical analysis showed significant difference between cultivars (P≤ 0.05). The Otono cultivar with the highest AUDPC and Zereshki cultivar with the least AUDPC were suggested as susceptible and resistance cultivars, respectively. The ANOVA of antioxidant enzymes showed positive effects on CAT, APX and GPX levels after inoculation (P≤ 0.01). Increasing in the amount of enzymes in incompatible interaction (Zereshki resistant cultivar) was greater than that of compatible interaction (Otono susceptible cultivar), indicates the role of these enzymes in activating plant defense responses in Faba Bean to interact with the pathogen and induce resistance. In general, the results showed that Zereshki cultivar with low level of AUDPC and high expression of antioxidant enzymes has high potential to be used in breeding programs for resistance to Alternaria leaf spot.