Evaluation of Resistance of Cucurbit and Cucumber Cultivars to Phytophthora drechsleri in Greenhouse

Root and foot rot caused by Phytophthora drechsleri is an important disease of cucumber in field and greenhouse. One of the best control methods of the disease is use of resistant cucumber cultivars or grafting cucumber plants on resistant cucurbit rootstocks. In the present study, resistance of fourteen cucurbit and cucumber cultivars at different growth stages was evaluated in greenhouse conditions using a completely randomized design in two replications. Susceptibility of cultivars was assessed by percentage of dead plants. Cultivars showed different responses to the disease and were classified into five very susceptible, susceptible, moderately susceptible, moderately resistant and resistant groups. Cucurbit cultivars Kadu Halvaee and Kadu Khoreshti Toopor va Kootah, and cucumber cultivars Boskoo and Dastgerdi with 100, 100, 99.30 and 92.34 percentage of dead plants, respectively were very susceptible and cucurbit hybrids RS841, RS107 and RS152 and Kadu Tanbal cucurbit cultivar with 23.60, 20.12, 15.03 and 10.18 percentage of dead plants, respectively were resistant.