UTILITY OF RAPD MARKERS IN IDENTIFYING GENETIC LINKAGES TO GENES OF ECONOMIC INTEREST IN PEACH

The identification of molecular markers linked to economically importa nt traits for use in crop improvement is very important in long-lived perennial species. Three-hundred-and-sixty RAPD primers were used with bulked segregant analysis to identify markers linked to loci of speci fic interest in peach [(Prunus persica) L. Batch] and peach x almond [ (Prunus dulcis) Batch] crosses. The traits analyzed included flesh col or, adhesion, and texture; pollen fertility; plant stature; and three isozyme loci. The Mendelian behavior of the RAPD loci was established, and RAPD markers were mapped relative to the loci controlling flesh c olor, adhesion, and texture, and the isozyme loci Mdh-1, 6Pgd-2 and Aa t-1, as well as the existing RFLP genetic linkage map constructed prev iously using a peach x almond F-2 population. This technique has facil itated rapid identification of RAPD and RFLP markers that are linked t o the traits under study. Loci controlling these traits mapped predomi nantly to linkage groups 2 and 3 of the peach genetic linkage map. Lin kages to genes with both dominant and co-dominant alleles were identif ied, but linkages to dominant genes were more difficult to find. In se veral. crosses, RAPD marker bands proved to be allelic. One co-dominan t RAPD formed a heteroduplex band in heterozygous individuals and in m ixtures of alternate homozygotes. The Mendelian behavior of the RAPD l oci studied was established and the results suggest that RAPD markers will be useful for plant improvement in peach.