Evaluation of resistance to cucurbit yellow stunting disorder virus in cucumber accessions

Yellowing diseases of field and greenhouse-grown cucurbits caused by whitefly-transmitted viruses are increasingly becoming important and cause economic losses in many cucurbits growing areas of the world. Using resistant cultivar is the best approach for plant virus control. To identify potential sources of resistance to an Iranian CYSDV isolate, (Bushehr isolate), fifty one accessions of Cucumis sativus, were evaluated under greenhouse conditions. Cucumber plants were inoculated at first true leaf-stage with viruliferous Bemisia tabaci. Three parameters were used to evaluate the reaction of cucumber accessions to CYSDV, including mean of disease severity index (10 weeks after the inoculation), time of symptoms development and virus accumulation in plant (mean ELISA value 8 weeks after inoculation). Although most accessions showed typical yellowing symptoms induced by CYSDV, However, the severity of symptoms, virus accumulation (absorption in ELISA) and the time of symptoms development were significantly different between cucumber accessions. Two accessions namely TN-94-229 and TN-94-206 showed delay in symptom development, low disease severity index and low concentration of the virus. They were therefore considered relative resistant to the CYSDV.