An integrated genetic linkage map of peach by SSR, STS, AFLP and RAPD

An integrated genetic linkage map, based on an intraspecific peach F-2 population, was constructed to include 94 simple sequence repeat (SSR) loci, 14 sequence tagged sites (STSs), 34 AFLPs, 24 RAPDs, 3 ISSRs, and 9 phenotypic traits. This map contains 178 markers placed in 8 linkage groups that correspond to the basic chromosome number of the species (n=8) with a map distance of 571 cM with an average distance of 3.2 cM between each pair of loci. Our peach genetic linkage map was completely aligned with the European Prunus reference map by using 42 common DNA markers as anchor loci and linkages; the order of all loci were conserved between the 2 maps. It also appears that this peach map covers almost the whole genome in comparison with the Prunus reference map. Nine phenotypic traits were identified in 4 linkage groups. Two kinds of root-knot nematode resistance loci Mia and Mja located on the top of linkage group 2 were very close. Two loci corresponding to flower color (Fc) and flesh color around the stone (Cs), were mapped on the linkage group 3. Flesh adhesion (F), one of the more important characteristics of stone fruits, was mapped at the bottom of linkage group 4. The positions these phenotypic traits were compared with those from other Prunus maps and their relationships were examined.