Preliminary results of new sweet cherry (Prunus avium) breeding program in Chile

Chile is the largest sweet cherry producer and exporter of the southern hemisphere. However, most sweet cherry production comes from cultivars originated in other countries. In 2010, the Chilean Export Association, a group of companies and the Pontificia Universidad Catolica de Chile began a traditional sweet cherry breeding program to obtain new cultivars adapted to Chilean growing conditions (e.g., low chill and rainy springs) and long-distance market requirements (e.g., China). The breeding program has focused in expanding the commercial window generating early and late cultivars. Each season around 3,500 and 4,500 hybrids are established in the field with an overall plant propagation efficiency that has ranged between 42.7 and 83.4%. To date, the breeding program has established over 21,000 hybrids on their own roots. Crosses are made either by hand or using cages to enclose whole trees. Hybrids are propagated by either using embryo rescue (40 to 45% hybrids) or seed stratification. Embryo rescue and seed stratification efficiencies have varied between 19.6 and 31.0% and 14.9 and 38.7%, respectively. Seedlings are maintained in greenhouse for about 6 months until establishment in the field. In 2014, first hybrids started bearing fruit and since then more than 600 individuals have been evaluated for yield, fruit quality (i.e., size, firmness, weight, color and SSC) and harvest date, among other characteristics. In 2017, a total of 14 interesting hybrids will be grafted on a dwarfing-precocious rootstock and established in two different locations for pre-commercial evaluations.