Susceptibility assessment of potato cultivars to Fusarium wilts

Fusarium wilt (Fusarium oxysporum f.sp. tuberose) is a major disease of potato, causing considerable damage and losses. The sources of genetically resistant are the best method of controlling the disease. In this study, the reactions of 18 potato cultivars were assessed to F. o f.sp. tuberosi in a factorial design with four replicates, in the greenhouse. Plants were inoculated (15 cm height) twice with three isolates of the pathogen by root inoculation (100 ml of 4×105 spore/ ml). Tento thirty days after inoculation cultivars were evaluated according to the symptoms disease index, the lengths of necrosis in vascular tissues, stem height and roots lengths There was a significant difference between parameters(P= 0.01). Necrosis lengths had maximum correlation in vascular tissues (r = 0.86), then root lengths(r = 0.75), symptom disease index scale (r = 0.73), and stem heights(r = 0.69). There was a significant difference between cultivars (P = 0.01). According to lengths of necrosis in vascular tissues cultivars divided in five groups, Gorican, Tiuva, Diamont, Marfona, Baraka, Aola and Moren were very susceptible and Olva, Folva and Alva were tolerant.