Temperate zone (deciduous) fruit crops are cultivated largely in areas far removed from their center of origin. Selection and breeding have improved climatic adaptation in these perennial crops. Current breeding programs are attempting to broaden this adaptation by developing cultivars with high mid-winter cold tolerance, late blooming to avoid spring freezes, and increased disease resistance. The attainment of these and other breeding objectives will recessitate the use of noncommercial exotic germplasm. The range of these fruits also is being extended to the subtropics and tropical highlands through selection and breeding. It is only through genetic manipulation that more productive and adapted plant materials are likely to be developed. Germplasm centers are needed to maintain and provide the array of genetic variability necessary for continued scion and rootstock improvement.