Evaluation of different grape varieties for resistance to powdery mildew caused by uncinula necator

Abstract

Powdery mildew is one of the most serious and destructive diseases of grapes around the world including Iran. Although the application of chemical pesticides is the most common control method, the use of resistant varieties may be the most effective and environmentally sound strategy for managing the disease. Fourteen grape varieties were evaluated for testing powdery mildew (Uncinula necator) resistance under natural infection conditions and artificial inoculation methods were used during 2007-2008 in Ardabil province of Iran. Disease severity on leaves and fruit (cluster) were evaluated using Voytovich (1987) procedure. Results of the experiments showed that Shahani, Yagothi and Tabrizkishmishi cultivars were immune, Sahibi cultivar was highly resistant, Agshilig and Tokoulgan were resistant, Kishmishi, Khalili and Tabarzeh cultivars were tolerant, Aldarag and Koupakbogan were susceptible and Garashilig, Seyrakpousteh and Rasmi cultivars were highly susceptible to the disease. In general, results of this study were promising and some immune, highly resistant and resistant cultivars to U. necator were identified and they may be used as a resistance genetic source for management of the disease in national and international programs.