Physiological races and vegetative compatibility groups among verticillium dahliae isolates from tomato in Israel

Three VCGs and two physiological races were defined among 76 Verticillium dahliae isolates from tomato recovered from 16 sites in Israel. Eighteen isolates were assigned to VCG2A, 55 isolates to VCG4B, two isolates were defined as VCG2B, and one isolate was self-incompatible. The physiological races were identified using two tomato differentials: cv.604 with the Ve gene for resistance to race 1, and cv. Rehovot13 susceptible to races 1 and 2. VCG2A and VCG2B isolates strongly affected only the susceptible cultivar and corresponded to the previously described race 1, whereas VCG4B isolates were virulent to both cultivars and corresponded to the previously described race 2. Cotton isolates of defoliating (D), defoliating-like (DL), and non-defoliating (ND) pathotypes induced no or only mild symptoms in tomato differentials. Likewise, race 1 and race 2 tomato isolates were mildly aggressive to cotton (Acala SJ2) and were defined as cotton ND pathotype. Races 1 and 2 represented by VCG2A and VCG4B, respectively, were similar for their pathogenicity in eggplant, okra, watermelon and sunflower, whereas two race 1 isolates belonging to VCG2B showed higher aggressiveness on eggplant, sunflower and watermelon.