Assessment of Resistance in Potato Cultivars to Verticillium Wilt Caused by and .

Verticillium wilt caused by spp., also called potato early dying disease, is one of the most serious soilborne diseases affecting potato production in China. The disease has been expanding into most potato production areas over the past few years. Information on host resistance against Verticillium wilt among the potato cultivars in China is scarce, but it is critical for sustainable management of the disease. This study, therefore, evaluated 30 commercially popular potato cultivars against strain Vdp83 and strain Vnp24, two well-characterized strains causing Verticillium wilt of potato in China. Both strains were isolated from diseased potato plants, and they were previously proven to be highly virulent. Ten plants of each cultivar were inoculated with the strain and incubated on greenhouse benches. Symptoms were rated at weekly intervals, and the relative area under the disease progress curve was calculated. The experiment was repeated once, and nonparametric analysis was used to calculate the relative marginal effects and the corresponding confidence intervals. Five resistant cultivars and four susceptible cultivars identified from the analyses were then challenged with the strain. Cultivar responses to were like those exhibited against , except for one cultivar. This study showed that resistance among potato cultivars exists in China against spp. and that the resistance to identified in potato is also effective against the other species that cause Verticillium wilt with a few exceptions. Cultivars identified as resistant to Verticillium wilt can be deployed to manage the disease until the breeding programs develop new cultivars with resistance from the sources identified in this study.