ln the Redher classification, the most widely adopted classification of Prunus L., there are more than 200 species divided into five subgenera with three for the stone fruits: Amygdalus, Prunophora and Cerasus. The major peach rootstocks are included in the subgenera Amygdalus (peach and almond species), mainly because there are no or very few problems of incompatibility grafting. Currently, the peach seedlings that are easy to produce and productive, are often used as peach rootstock, except in the calcareous soils where peachxalmond hybrids are preferred. Prunophora species are chosen for a better adaptability to heavy soils, or for introducing resistance genes to nematodes, to fungus or bacterial soil-diseases. The grafting of Prunophora species induces lower vigor for Amygdalus species and can initiate more problems of grafting incompatibility. So, a breeding program which integrates Prunophora species will be longer in time than one using only Amygdalus species. The main selected traits in the world peach rootstock breeding programs worldwide are still nematode resistance, waterlogging, vigor control, calcareous soils, and drought. For each trait, several Prunus genotypes may fit the requested characteristics, and it is important to choose the best crossing strategy which aIlows the breeder to obtain the best performance for aIl traits in order to replace an existing rootstock