Citrus breeding program in Chile

Mandarin production and exports from Chile have shown a huge growth in the last ten years. During the 90'sthe most important cultivar was 'Clemenules' and since 2005 mandarin hybrids are being planted to supplylate season markets. This has resulted in the production of fruit with seeds due to cross pollination causingbig losses to Chilean producers. In 2007 citrus breeding program was initiated in the Pontificia UniversidadCatólica de Chile with the support of CIRAD (France) and University of California Riverside. The aim of thisprogram was to obtain seedless mandarin and lemon cultivars. Strategies used are induced mutation by gammairradiation, in vitro triploid rescue obtained from diploid crosses, production of auto-tetraploid plants andthe establishment of a protoplast fusion protocol. Irradiation technique has resulted in the establishment of5700 mandarins and 2500 lemons in a field trial located in Pomaire, Chile (33°39'S, 71°10'W). Field evaluationresulted in the selection of 164 lemon and 14 mandarin seedless selections, 4 lemon thornless selection, and2 ornamental types. Our methodology allowed an early selection of seedless genotypes and quickly reducedthe number of plants under evaluation. 118 triploids were obtained through in vitro rescue from diploidmandarins cross pollinations. These genotypes are currently under agricultural practices to induce floweringand are prone to be planted in commercial trials. 9 tetraploid of reduced juvenility were obtained with theuse of colchicine in axillary buds. They will be used in cross pollinations in 2012 spring. Finally a protoplastfusion protocol has been developed under our conditions. The results of this program have a high impactfor the Chilean citrus industry and the academy, since they have allowed creating varieties adapted to localconditions, a new line of research and training for new professionals.