Recent achievements and future challenges in breeding for European plum cultivars: finding the suitable genetic resources for important traits

Due to changing biotic and abiotic factors affecting the plants, certain traits become more important in European plum (Prunus domestica L.). These include resistance to winter and late frosts, the tendency to develop heat damage on the fruits, to stone cracking and to form double fruits. Resistance to Plum pox virus is available in the form of hypersensitivity resistance and will retain its important role in cultivar breeding, as will breeding for excellent fruit quality. However, it is a breeding challenge to combine the newly relevant traits in new cultivars in the best possible way. This requires precise knowledge of the degree to which the traits in question are genetically determined. It is shown that the phenotypic characterization of collections of genetic resources can make a valuable contribution to breeding.