Evaluation of resistance in different grape cultivars against Uncinula necator in Meshkinshahr region, Iran

Powdery mildew is one of the most serious diseases of grapevine in all over the world including Iran. It can impose remarkable losses to grapvien orchards in favorable condition. In this experiment, 14 cultivars of grapes including Shahani, Kishmishi, Rasmi, Tokolgan, Garashilig, Seyrakpousteh, Khalili, Tabarzeh, Koupakbogan, Aldarag, Sahibi, Agshilig, Yagothi and Tabriz-kishmishi were evaluated under natural infection and artificial inoculation during 2007- 2008 in Meshkinshahr region. Disease severity on leaf and fruit cluster was evaluated by Wang and Voytovich scales in which 0: immune, 1: very resistant, 2: resistant, 3: tolerant, 4: susceptible and 5: very susaptable. Shahani, Yagothi and Tabriz-kishmishi cultivars were Immune, Sahibi was highly resistant, Agshilig and Tokoulgan were resistant, Kishmishi, Khalili and Tabarzeh were tolerant, Aldarag and Koupakbogan were susceptible and Garashilig, Seyrakpousteh and Rasmi were highly susceptible to powdery mildew. In general, in highly infected areas, using Shahani, Yaghuti, Tabriz-kishmishi would be more recommendable for new grapevine orchard establishment.