PROGRESS AND PROSPECTS IN STONE FRUIT BREEDING

During the last decade, important progress has been achieved in the breeding of species of Prunus, known collectively as stone fruits, in order to obtain new cultivars adapted to different biotic or abiotic conditions, as well as responding to consumer demands for quality.
In most countries where stone fruits are grown both research institutions and private breeders are involved in improvement programs.
The level of knowledge has considerably increased, especially in genetics and biotechnology.
Molecular biology has permitted an understanding of genome structure and genetic diversity of Prunus, particularly for cherries and plums.
Wide genetic variability exists in most stone fruit species and remains to be exploited.
Increased knowledge of Prunus genetics is emerging from analysis of inheritance of fruit characters (color, size, firmness) and yield (limitation of juvenile phase, early and regular productions, limitation of alternate bearing). More effort is needed in respect to quality (good flavor, aroma, nutritional compounds, storage quality, and elimination of different toxins). The largest challenge concerns disease resistance, especially for the quarantine pests present in different parts of the world such as sharka disease, Xanthomonas arboricola pv pruni. A combination of genetic, pathological and epidemiological approaches is necessary.
New sources of resistance and different strategies of breeding are required including monogenic and polygenic resistance, and genetic transformation.
An increase in availability of new resistant germplasm, although not always of commercial level, is foreseeable in the short and medium term.
The capacity for combining different objectives could be greatly improved by increased knowledge of the species genomes and molecular approaches.
The strategies developed on annual crops and a better knowledge of synteny in the Rosaceae are required to increase efficiency of stone fruit breeding.
New objectives for the future development of stone fruits must be related to environmental adaptability as a consequence of climatic changes and the necessity to adapt species and cultivars to new zones of cultivation.