2007 Annual Report 1a.Objectives (from AD-416) The objective of the cooperative research between the University of Georgia Research Foundation, Inc. and the USDA Agricultural Research Service is to evaluate and identify sources of resistance to wheat stripe rust and incorporate and identify sources of resistance to wheat stem rust. 1b.Approach (from AD-416) The University of Georgia will obtain, plant, manage, evaluate, and harvest (if needed) uniform nurseries and other germplasm sources of wheat for evaluation to the wheat stripe rust pathogen, Puccinia striiformis. The wheat germplasm will be evaluated for resistance by Georgia Experiment Station personnel using standard evaluation rating scales at one or more locations in the State of Georgia, where stripe rust is known to occur. Data will be put into a standard electronic format and given to the ARS project coordinator. 3.Progress Report This report serves to document research conducted under a specific cooperative agreement between ARS and the University of Georgia. Additional details of research may be found in the report for the parent CRIS 6645-22000-015-00D. The Uniform Eastern Stripe Rust Nursery and nurseries with elite wheat germplasm from the University of Georgia and other breeding programs in the southeast were grown in 2006-2007 at Griffin and Plains, GA for evaluation to wheat stripe rust. The nursery was planted on November 3 and November 12, 2005 at two locations, Griffin and Plains, respectively and inoculated with stripe rust from current races of stripe rust collected in Georgia during the spring of 2006. The races were identified and designated as PST 101 and 102 by Dr. X. M. Chen, USDA-ARS, Pullman, Washington. Twelve inoculated spreader pots of AGS 2000 were randomly transplanted in the nursery within the rows. The site was irrigated as needed during the growing season. In early February, infection was detected within the nursery. By mid March the infection was an epidemic. Natural infection was also observed in other nursery plots. Rapid and complete spread of the disease was observed throughout the nursery. Infection types were assessed on the stripe rust expanded 1-to-9 scale where 1-3=resistant, 4-6=intermediate, and 7-9=susceptible. Within the nursery, approximately 25% of the lines were rated as resistant. Both adult and seedling resistance were detected within the germplasm in the nursery. The data was collected, analyzed, and reported to Dr. David Marshall. Several lines resistant to stripe rust have the Lr37Yr17 complex. Additional sources of resistance, PIO26R61 and GA951395-3A31, were identified. Crosses have been made to determine the genetics of these additional sources of resistance to stripe rust. ADODR (D. Marshall) confers with the cooperator by phone after planting to assess progress, in late winter to assess nursery inoculation, and in spring to assess disease progress. Dr. Marshall visits both nursery locations in the spring to assist in disease severity assessments.