Pathogenicity and phenotypic characteristics of the strains causing potato wilt in Hamedan province

Potato bacterial wilt disease caused by Ralstonia solanacearum is one of the important diseases in Hamedan province. The objective of this study was determination of phenotypic characteristics and diversity of pathogencity of the causal agent bacterial wilt. In this study، potato samples were collected from different fields in Hamedan province during the spring and summer of 2011. A total of 78 strains of R. solanacearum were isolated on NA mediu، containing triphenyl tetrazolium chloride (TTC) and finally 65 representatives were selected for further investigation. Bacterial colony morphology showed a wide range of variation and they were identified as R. solanacearum race3 bivar 2. The pathogenicity variation pattern of the strains was investigated on tomato plants in a randomized design with three replicates. Symptoms، including wilting number of yellow leaves، epinasty rate، were recorded and analyzed. Results showed significant differences among the tested strains.