Identification and Selection of Brown Rot Resistance Genes in Peach

Brown rot caused by Monilinia spp., is the most important disease of stone fruits worldwide. In the U.S, Monilinia fructicola and Monilinia laxa cause blossom blight and fruit rot, with consequent yield losses, in peach (Prunus persica [L.] Batsch) and in all Prunus crop species. Brown rot is a serious problem for peach growers both before and after harvest. Fruit susceptibility changes during the course of development; mature fruit are highly vulnerable to new infections and to quiescent infections that emerge just prior to and following harvest. Pop-DF a population derived from crosses between ‘Dr. Davis’בF8,1-42’, a peach introgression line derived from an initial almond × peach interspecific hybrid, was evaluated for brown rot blossom blight and fruit rot resistance during three years. Using the previous published SNP linkage map of Pop-DF and the phenotypic data collected, a QTL analysis for brown rot resistance was carried out. Several markers have been associated a QTLs for brown rot, the results show a QTL for brown rot on linkage group 1 and an additional QTL appears to be located on linkage group 5. This information, combined with our recent SNP effects analysis of the Pop-DF sequence data provides tree fruit breeders with additional tools for developing brown rot resistant cultivars.