Resistance of olive cultivars to Verticillium dahliae.

Seventeen important olive cultivars have been evaluated for resistance to Verticillium dahliae under controlled conditions. One-year-old nursery olive plants were inoculated with cotton defoliating (D) (Mn 16) isolate (VCG1) of V. dahliae. Resistance was evaluated by assessing symptom severity using a 0- 4 rating scale and estimating the area under disease progress curves. Besides, additional parameters for including cultivars into a defined category were used such as the percentage of plants killed and those which recovered from the disease. All cultivars were susceptible to isolate of V. dahliae at different levels. ‘Wild 6 ’ and ‘Gemlik 2 ’ were moderately susceptible to isolate of V. dahliae. Their resistance was evident by the plant ability to recover from infection with isolate.