Breeding Oil and Table Olives for Mechanical Harvesting

The olive and table olive industries in the world are almost entirely supported by local cultivars empirically selected by farmers through centuries. New early and high bearing plantation systems adapted to mechanical harvesting have being designed and developed during the last fifty years. Intensive rainfed (150- 200 trees/ha) and irrigated (250-400 trees/ha), high density irrigated large hedgerows (400-800 trees/ha) and very high density hedgerows (superintensive) rainfed (800-1000 trees/ha) and irrigated (>1,500 trees/ha) orchards are being progressively planted to be harvested by different mechanical systems. However, these orchards depend on traditional cultivars in most cases. In Spain a long term effort on exploration, conservation and sustainable use of olive genetic resources starting in 1970 has been followed by breeding programs developed since early 1990’s by the Universities of Córdoba and Seville and the IFAPA to obtain new cultivars adapted to mechanical harvesting by cross breeding. Methodological (shortening the Juvenile Period (JP) and developing early tests of selection), agronomical (earliness of bearing, high cropping, tolerance to abiotic stresses and resistance to main diseases, particularly to Verticillium wilt, and low chilling requirements) and industrial suitability (high oil content and diversity olive oil composition for oil cultivars and fruit size and shape for table olives) objectives are being pursued. Specific criteria for adaptation of oil olive and table olive cultivars to mechanical harvesting such as low vigor trees with compact habit of growth, fruit removal force, natural fruit abscission, resistance to bruising and enlarging ripening time among cultivars of compressed maturity period are evaluated in progenies.  Up to date many progenies have been already evaluated and more than 400 preselections are on intermediate field trials. More than 30 advanced selections are being established in a network of field trials open to private and international cooperation. A new protected cultivar ‘Sikitita’ (‘Chiquitita’ in the USA), selected for very high density narrow hedgerows, was released in 2008 and it is currently authorized for propagation in 12 countries. Recently a first project on olive genomics heralds the use of MAS in the midterm.  Cultivars adapted to the new mechanical harvest systems will be progressively released in the future.