Response of Commercial Poato Cultivars to Common Scab Disease in Isfahan and Freydan

Responses of some potato cultivars to scab disease (Streptomyces scabies) were evaluated in the field conditions of Isfahan and Freydan in 2007 using a randomized complete block design. Response of cultivars was assessed based on seven infection classes of potato tubers according to NIAB descriptor diagram. For disease assessment, perCentage of infected tubers, disease severity and disease index of tubers were determined. The means were compared according to Duncan`s multiple range test. The results showed significant differences among the cultivars for all assessed criteria. In Isfahan cultivars Milova and Sante had the lowest and Maradona and Granula had the highest infection. In Freydan, cultivars Cosima and Sonate had the lowest and Arinda and Diamont had the highest disease index and disease severity. Combined analysis of the data showed also the similar results.