A genetic linkage map constructed by using an intraspecific cross between peach cultivars grown in Japan

A linkage map of the peach (Prunus persica (L.) Batsch), was constructed by using 133 F-2 plants from the intraspecific cross between the rootstock cu ltivar, 'Akame', and the flowering ornamental peach, 'Juseitou'. This map c ontains 83 markers, including 3 morphological trait loci, brachytic dwarf ( dw), red leaf (Gr) and narrow leaf (nl), 41 RAPD markers, 30 AFLP markers, and Inter-SSR, PCR-RFLP markers. Ten linkage groups were found, ranging fro m 17 to 244 cM in genetic distance; among these, the 6 major groups had gen etic distances of more than 60 cM. The map covers more than 960 cM with an average density of 12 cM between markers. A newly designated morphological characteristic, narrow leaf character (designated nl) was found to cosegreg ate with the dw locus. We found that 3 morphological traits, dw (nl) were l ocated on the same linkage group as the Gr locus at a distance of 65 cM. Se veral DNA markers were linked to Gr and dw loci, which could be utilized no t only for selecting morphological traits but also for evaluating homozygos ity or heterozygosity. For example, the 95 bp AFLP fragment produced from t he E-AGT/M-CAA primer combination, is tightly linked to the Gr locus at a d istance of 5.0 cM. The DNA markers obtained are horticulturally very import ant and will be utilized for peach breeding.