2010 Annual Report 1a.Objectives (from AD-416) Identify molecular markers specific to Aphanomyces eiteiches Race 1 and 2. 1b.Approach (from AD-416) Collect fungal isolates from various geographical regions. Extract DNA from each and combine from each respective race (bulked DNA). Use RAPD, SRAP, or other primers to screen for polymorphisms specific to each race. Develop SCAR markers from sequence derived from the latter markers. Documents SCA with WSU. 3.Progress Report Isolates of Aphanomyces euteiches Race 1 (R1) and Race 2 (R2) were obtained from alfalfa fields in Illinois, North Carolina, Washington, and Wisconsin. A single sequence related amplified polymorphism (SRAP) marker was identified across five R2 isolates that did not occur in DNAs of four R1 isolates. No polymorphisms were detected in R1 or R2 using RAPD primers so far. Additional SRAP and RAPD markers are being screened to identify markers specific to R1 and to obtain additional markers specific to R2. More isolates of both races are being collected to increase the screening panel size in order to better evaluate the robustness of the markers. The goal of this project is to identify molecular DNA markers to distinguish between the two races of Aphanomyces euteiches that cause root rot on alfalfa. This contributes directly to Objective 1 of the in-house project. This project was monitored by monthly communications with the cooperator.