Mining of Fire Blight and Apple Scab Resistant Alleles in Malus Germplasm: Apple production contributes $14 billion/yr to the US economy. Emergence of new pathogen strains and changing environment continually threaten sustainability of this long-lived perennial crop and require development of new cultivars with increased stress tolerance and enhanced traits. This effort is hindered by a lack of access to functional alleles within a vastly diverse collection of unrelated accessions and crop wild relatives. We are using a targeted strategy to select donor stocks carrying favorable alleles for disease resistance within the world’s largest and most diverse collection of apples: the USDA-ARS Plant Genetic Resources Unit at Geneva, NY. We will employ a novel strategy for focused selection of germplasm and to characterize host resistance by combining historical disease evaluations, phylogenetic relationships, eco-geographical information, and co-occurrence of pathogen strains. This effort will be strengthened by development and implementation of molecular marker system to tag haplotypes of allele donors for known resistance and to identify novel alleles.