Department of Plant Sciences Mail Stop 2, University of California, 1 Shields Avenue, Davis, CA 95616, USA; e-mail: dpotter@ucdavis.edu

Stone fruits-almonds, apricots, cherries, peaches and nectarines, and plums (Table 1-1)—belong to the large cosmopolitan genus Prunus L., which in turn is classifi ed, along with strawberries, raspberries, blackberries, apples, pears, and roses, in the large and diverse family Rosaceae. All of the major fruit crop species in Prunus originated in temperate regions of the Old World, in areas from eastern Europe to eastern Asia, but are now cultivated throughout the world and are of enormous economic importance. Each category of stone fruits also includes several minor crops and/or wild species, many of which have been important to some degree in the genetic improvement of the main crop species. In addition to the stone fruits, the genus includes a signifi cant number of species cultivated as ornamentals, several that are valued for their wood, and at least one wild species (P. africana) of global economic importance due to its medicinal properties, as well as others that have traditional local medicinal uses in their native regions. This chapter presents a brief description of the botany of the stone fruit species, including their morphology and systematics, an overview of their status as world crops, including their origins and histories, data on their nutritional value and current economic signifi cance, a review of topics of research interest and a summary of available germplasm for Prunus.