Evaluation of Verticillium wilt resistance in selections from olive breeding crosses

Verticillium wilt (VW) resistance was evaluated in genotypes from olive crosses including resistant cultivars as parents. Thirty-eight genotypes from three crosses were evaluated: 'Changlot Real' 9 'Dolce Agogia' (16), 'Frantoio' 9 'Arbosana' (13) and 'Koroneiki' 9 'Empeltre' (9). These genotypes were previously selected for several agronomic traits from wider initial progenies populations. Several disease severity and plant colonization parameters were evaluated in inoculation experiments under controlled conditions by dipping roots cutting in a conidial suspension of a highly virulent defoliating isolate of Verticillium dahliae. Significant differences among the evaluated genotypes, including parents and selections from crosses, were obtained for all the disease parameters assessed. A wide variability in disease parameters was observed in the three cross combinations tested. Genotypes with lower relative susceptible index values than both parents were found in the three progenies tested and 10 out of 38 genotypes (26 %) were finally classified as resistant. The level of resistance of these genotypes will be confirmed in future studies under field conditions.