Genetic mapping of the evergrowing gene in peach [Prunus persica (L.) Batsch]

In temperate locations, terminal apices on evergrowing (also called evergreen) peach trees keep growing in winter until killed by low temperatures, while the lateral buds go into dormancy. A recessive allele of a single gene (evergrowing or evg) controls this trait in peach. The amplified fragment length polymorphism (AFLP) technique and bulked segregant analysis were applied to construct a local genetic linkage map for the evg gene from the cross Empress op op dwarf x Evergrowing (P.I. 442380). This map, comprising nine AFLP markers and the evg locus, covers a total genetic distance of 79.3 cM. Four dominant AFLP markers (EAT/MCAC, ETT/ MCCA2, EAT/MCTA, and ETT/MACC) were linked to the evg locus at distances of 1, 5.3, 6.7, and 11.7 cM, respectively. EAT/MCAC and EAT/MCTA were converted into polymorphic sequence-tagged sites. Microsatellite markers in the evg region were developed from peach bacterial artificial chromosome (BAC) clones that hybridized to the AFLP marker fragments. Using three microsatellite anchor markers (pchgms12, pchgms17, and pchgms19), the local genetic linkage map was integrated into one minor linkage group of a previously constructed peach rootstock genetic linkage map. Three AFLP markers from the rootstock genetic linkage map were found linked to the evg locus.