Identifying resistance to Verticillium wilt in local Spanish olive cultivars

The resistance of 42 Spanish olive cultivars to Verticillium dahliae was evaluated in two experiments carried out in two consecutive years, conducted under greenhouse conditions. In both experiments, bare root systems of 5-month-old plants were inoculated with a semisolid mass of a mixture of culture medium and conidia and mycelium of the fungus. The cultivars Frantoio and Picual were used, respectively, as resistant and susceptible reference cultivars. All cultivars were evaluated on the basis of final values of the area under the disease progress curve, mean severity of symptoms and percentage of dead plants. Most of the tested cultivars were susceptible to Verticilium wilt. However, eight genotypes (‘Cornezuelo de Jaén’, ‘Verdial de Badajoz’, ‘Jaropo’, ‘Negrillo de Estepa’, ‘Jabaluna’, ‘Ocal de Alburquerque’, ‘Asnal’ and ‘Racimal’) exhibited resistance to the disease