ALIGNING MALE AND FEMALE LINKAGE MAPS OF APPLE (MALUS-PUMILA MILL.) USING MULTI-ALLELIC MARKERS

Linkage maps for the apple cultivars 'Prima' and 'Fiesta' were constru cted using RFLP, RAPD, isozyme, AFLP, SCAR and microsatellite markers in a 'Prima' x 'Fiesta' progeny of 152 individuals. Seventeen linkage groups, putatively corresponding to the seventeen haploid apple chromo somes, were obtained for each parent. These maps were aligned using 67 multi-allelic markers that were heterozygous in both parents. A large number of duplicate RFLP loci was observed and, in several instances, linked RFLP markers in one linkage group showed corresponding linkage in another linkage group. Distorted segregation was observed mainly i n two regions of the genome, especially in the male parent alleles, Ma p positions were provided for resistance genes to scab and rosy leaf c urling aphid (Vf and Sd(1), respectively) for the fruit acidity gene M a and for the self-incompatibility locus S. The high marker density an d large number of mapped codominant RFLPs and some microsatellite mark ers make this map an ideal reference map for use in other progenies al so and a valuable tool for the mapping of quantitative trait loci.