Sanitary selection of olive (Olea europaea L.) cultivars for worldwide distribution

Background: Olive growing is an important agriculture branch worldwide and especially in Italy, where to avoid spread of the most dangerous olive pathogens several decrees regulate the certification program of plant propagating materials. Specifically, Verticillium dahliae, Pseudomonas savastanoi, phytoplasmas and viruses, due to their biological (systemic pathogens) and pathological (they induce severe diseases or are latent in olive but dangerous for other crops) characteristics are considered regulated pathogens. In order to divulge this positive experience this study described the way of adding new olive varieties to the certification program in Italy. Materials and Methods: Seventy two of the main olive cultivars grown in various Italian regions (Central and Southern Italy) were selected, observed and analyzed for the presence of Verticillium dahliae, Pseudomonas savastanoi, phytoplasmas and viruses. Specifically, all olive trees were analyzed by visual inspection for the presence of characteristic symptoms of verticillium wilt, olive knot, bumpy fruit and vegetative disorder in general, isolation for the fungus and molecular amplification for phytoplasmas and viruses, in different seasons through 2 years of activity. Results: The conducted survey allowed 10 cultivars from Calabria, 18 from Campania, 8 from Lazio and 10 from Umbria to be included in the Italian certification program. Conclusion: The use of these certified materials reduces risks of pathogen dissemination, ensure the commercialization of high quality olive plants and it is strongly recommended in the introduction of olive plants in a new area. The Italian certification program, validated also for other European countries can be easily adopted to any areas suited to the olive growing in order to avoid the risk of spreading dangerous pathogens and to improve olive oil production.