Screening for resistance of Turkish olive cultivars and clonal rootstocks to Verticillium wilt

Verticillium wilt resistance of 77 olive cultivars including 71 domestic and six foreign ones, and four clonal rootstocks available in the olive gene bank, were tested using a highly virulent isolate (D pathotype) of Verticillium dahliae. The pathogen was stem-inoculated into the own-rooted saplings. Most cultivars and rootstocks were found to be extremely susceptible to the disease. 'Sinop No. 1', 'Egriburun Nizip', 'Erkence', 'Egriburun Tatayn', 'Girit Zeytini' and 'Marantelli' were highly resistant, as their disease severities did not exceed 10%. Additionally, 11 domestic cultivars ('Sari Habesi', 'Yaglik Celebi', 'Zoncuk', 'Dilmit', 'Sam', 'Hurma Karaca', 'Erdek Yaglik', 'Melkabazi', 'Yun Celebi', 'Kan Celebi' and 'Siyah Salamuralik'), two foreign cultivars ('Arbequina' and 'Frantoio') and one wild clonal rootstock ('D36') were found to be resistant, with disease severities less than 30%. On the other hand, the moderately susceptible group comprised ten domestic cultivars ('Ak Zeytin', 'Yag Celebi', 'Saurani', Butko', 'Gemlik', 'Otur', 'Yag Zeytini', 'Belluti', 'Sinop No. 2' and 'Samanli'), three foreign cultivars ('Leccino', 'Chemlali' and 'Ascolana') and one wild clonal rootstock ('D9'). The number of cultivars within highly resistant and resistant groups was 17 out of the 71 domestic cultivars from all regions (four from Aegean, seven from southeastern Anatolia, two from Black Sea and three from Marmara).