2010 Annual Report 1a.Objectives (from AD-416) 1. Identification of PD resistance genes in Vitis species. 2. Molecular determination PD resistance mechanisms. 1b.Approach (from AD-416) 1. Identify candidate R genes from microarray global gene expression analyses. 2. Cloning and molecular characterization of target genes using in vitro expression system. 3. Develop R gene molecular markers for marker-assisted selection. 3.Progress Report The agreement was established in support of Objective 2 of the in-house project to enhance molecular marker developments for biotic stress, resistance breeding and germplasm evaluation in grapes through the identification and characterization of biotic stress resistance (R) genes and their analogs. The research strategy is based on bioinformatic and molecular approaches to identify candidate R gene loci and develop biomarkers that are linked to the phenotypes. Ten parental lines, three breeding populations and twenty-four Vitis species were provided by collaborators for evaluating the utility of these primers. During the report period, ARS scientists visited the collaborator three times. Both parties actively engaged in research discussions through email and phone. These efforts resulted in the development of 24 molecular markers that were confirmed to detect polymorphic patterns in resistant and susceptible parental lines as well as their segregating/recombination patterns in a number of segregating populations. These R gene-based markers will facilitate the saturation of current SSR-based marker mapping populations and provide a quick identification of trait-associated markers for target breeding. Research activities were monitored by the ADODR through email and telephone communication with the cooperator. Research results were distributed in both grower and professional meetings.