When considering a broad cross section of climates and growing regions, the peach (Prunus persica (L) Batsch) is the most prevalent of the stonefruits, rivaling apple in terms of adaptation. The broad distribution reflects its extensive cultivation, as its prized fruits drove its rapid dissemination and selection for adaptation to new areas. The relatively short juvenility period and ease of making controlled crosses have made the peach the most successfully bred tree fruit crop. Today more Mendelian transmitted traits are understood in peach than in any other tree (Scorza and Sherman, 1996). These facets, in conjunction with a small genome size have made peach a desirable system for breeders and bench scientists focused on the common goal of tree fruit improvement. Peach is a member of the family Rosaceae, subfamily Prunoidae. It is a member of the subgenus Amygdalus, that contains peaches, peach relatives and almond relatives. The most closely related species to peach are P. mira Koehne, P. kansuensis Rehd., and P. davidiana (Carr.) Franch. Members of this subgenus are sexually compatible and produce viable and fertile F1 hybrids (Martinez-Gomez et al., 2003). These species have been used to extend the genetic pool in peach and serve as sources of insect, pathogen, and nematode resistance for breeding of peach scions and rootstocks (Martinez-Gomez et al., 2003). Peach evolved in a more mesic environment than the almonds and are typically characterized by a fleshy fruit that does not dehisce, in contrast to almonds (Martinez-Gomez et al., 2003). Peach is represented in the wild as P. persica subsp. ferganensis in Tajikistan, Kyrgyzstan and Uzbekistan (Okie and Rieger, 2003) and may also be represented by Mao Tao (hairy peach) type peaches of China. Clearly defined wild peach populations have not been reported in China and the Mao Tao peach is probably the most primitive (ancestral) form. Wild species have been cultivated near the Chinese center of origin for at least four thousand years (Rieger,