The Rosaceae Family is represented by approximately 3,000 species of diverse plants, primarily con?ned to temperate climates. The family has a rich variety of architectural forms and contains herbaceous, tree and shrub species. Many family members are readily recognizable because of their edible seasonal fruits that are prized for their unique ?avors, colors and nutritious properties (e.g. apple, str- berry, raspberry, pear, cherry, plum, apricot, pear), as well as familiar ornamentals (e.g. roses) and nuts (e.g. almonds). Today's rosaceous cultivars have been derived from centuries of careful sel- tion and breeding, using a palette of some of evolution's most curious creations. The careful sculpting that has transformed the germplasm was not trivial, as several of the most coveted fruit species maintain complicated genomes-in some cases among the most complex of cultivated plants (e.g. strawberry). Other species in the family are represented by large perennial tree crops that exhibit substantial juven- ity phases, posing a barrier to standard breeding and genetic analyses.
Yet, today's superiorcultivarsfeaturerobustgrowth,substantialyieldsandresistancetocommon biotic and abiotic stresses; traits fostered by human intervention. When the hurdles to ef?cient cultivation, breeding and selection are considered, the quality and qu- tity of rosaceous plant products derived from traditional breeding techniques is little short of amazing.