Resistance evaluation of some commercial Vitis vinifera varieties to powdery mildew Erysiphe necator Schwein. in two regions of Iran

Powdery mildew, caused by Erysiphe necator is a common and severe fungal disease of grapevine all over the world including Iran. Although the application of chemical fungicides is the most common control method, the use of resistant varieties may be the most effective and environmentally sound strategy for managing the disease. Twenty two grape varieties were evaluated against powdery mildew under natural infection and artificial inoculation during 2011-2013 in Ardabil and Qazvin provinces of Iran. In this study, Perlett, Robee seedless, Flame seedless and Tompson seedless varieties were immune; Mish-Pestan, Khoshnav and Torkamanestan 8 were highly resistant; Torkamanestan 4 and Superior seedless were resistant; Shahani-e-Qazvin and Shast-e-Arous were tolerant; Ghermez-e- Bidaneh, Sefid-e-Bidaneh, Fakhri, Sahebi-e-Ghermez, Peikami, Rishbaba-e- Sefid, Siyah-e-Samarghandi and Rotabi were susceptible and Rishbaba-e- Ghermez, Asgari, and Shahroodi were highly susceptible varieties to grape powdery mildew. In general, findings of this research may be used as resistance genetic sources for management of the disease in national and international programs.