The Chilean nectarine breeding program toward development of chilling injury-resistant cultivars

Chile has a long tradition in exporting nectarines to international markets. Its production goes mainly to Northern hemisphere countries, needing up to 30 days of ship journey before arriving to the final consumer. Till 2015 the only nectarines exported provided from cultivars developed by foreign breeding programs, mainly Californian ('August Red', 'Flamekist', 'Firebright' and 'Venus', among others). In general terms, few cultivars exported by Chile fitted the required phenotype, most of them after two weeks in cold storage were prone to develop flesh's internal disorders. In 2000, the University of Chile initiated a breeding program aimed in creating cultivars that could stand for long postharvest periods maintaining a high sensory quality, thus generating the base for a globalized market for fresh nectarines. At the same time a research program was carried out, focused in developing novel approaches for measuring the targeted traits. The objective determination of the flesh's mealiness and browning was setup through in-house created methods. The actual physiological ripeness of seedling's fruits has been determined non-destructively through the chlorophyll absorption of the skin. The fruit sensory evaluation has been determined through consumer tests and with trained panels as well. A genomic platform was developed, activating tight collaborations with other research groups, aimed to define the genetic diversity of the used germplasm and the implementation of some molecular markers associated to valuable traits.