Potato early dying (Verticillium wilt), is an important disease all over the world. Both species, Verticillium dahliae and Verticilliumalbo-atrum are prevalent in potato fields of Fars province. V dahliae is more encountered regarding climatic factors. Using tolerant cultivars is an efficient way of control. In this study susceptibility of 19 potato cultivars and 32 selected clones obtained from symptomless plants in the fields, were evaluated toward V dahliae isolate no. 30 in the greenhouse and in field. In the greenhouse, single buds were transferred to the pots and inoculated with 50 ml spore mycelial suspension (the content of one Petri dish in 300 ml distilled water). For the control treatment, single buds were inoculated with sterile distilled water. In fields, whole tubers of the cultivars were inoculated with 50 ml of spore mycelial suspension. The results indicated that cv. Famosa and clone 27 which caused no reduction in the growth period and less than 20 percent yield reduction, were regarded as tolerant. Other cultivars such as Agria, Ajax, Arinda, Binela, Cardinal, Concord, Cosima, Eba, Estima, Herthea, Impala, Kondor, Marfona, Moren, Olivia, Picaso, Primier, Sandra and 31 selected clones were found to be susceptible or very susceptible. |