Peaches

Abstract

Common goals of peach breeders are: (1) extending the harvest season, (2) improving flavor and aroma, (3) lengthening self life, (4) controlling tree size, (5) broadening the adaptive range, and (6) developing resistance to sharka (PPV), powdery mildew, brown rot, leaf curl, Xanthomonas spp. and the green aphid (the vector of PPV). A number of single genes have been identified that reduce tree size and modify plant shape, and regulate firmness, mealiness, melting flesh, browning, flesh color and the freestone trait. Fruit maturity has been shown to be quantitatively regulated with a very high heritability. A growing number of molecular linkage maps have been developed of peach and its relatives; map coverage ranges from 396 to 1300 cM, with 8 to 23 linkage groups being identified. QTL have been identified for numerous horticulturally important traits including bloom and ripening time, fruit quality, storage life, freestone trait, internode length and pest resistance. Several bacterial artificial chromosome (BAC) libraries have been developed for peach and over 85,000 Prunus ESTs have been sequenced and deposited in the NCBI dbEST database. Peaches have been regenerated utilizing several systems, but there are only two reports of stable peach plant transformation.