2007 Annual Report 1a.Objectives (from AD-416) Evaluate 7,300 National Small Grains Collection (NSGC) Iranian wheat accessions and additional selected NSGC wheat germplasm for reaction to biotype B of the Russian wheat aphid (Diuraphis Noxia). Germplasm found resistant in this evaluation will be further screened to biotype A. 1b.Approach (from AD-416) Evaluations will begin with a group of 7,300 Iranian landrace selections that were recently added to the NSGC. These accessions have been evaluated by other researchers (CIMMYT, UNIV. CALIFORNIA-DAVIS) for Russian wheat aphid (RWA) and other agronomic characteristics but have not been evaluated for resistance to the new RWA biotype B present in Colorado and adjacent states. As many of the resistant accessions for the original screenings by the USDA-ARS (Stillwater, OK, 1988-1995) originated from Iran, there is expectation that this new collection will contain very promising accessions. A second set of materials, numbering approximately 5,000, will also be evaluated. These are materials from various origins that have never been evaluated for resistance to RWA biotype. From this group of approximately 12,000 accessions, sources identified as resistant will be evaluated in separate experiments for resistance to the RWA Biotype A. As each cycle is completed, data collected will be added to the germplasm resources evaluation network (GRIN).Documents SCA with University of Colorado, Ft. Collins, CO. 3.Progress Report This report serves to document research conducted under a specific cooperative agreement between ARS and Colorado State University – Scott Haley. Additional details of research can be found in the report for the parent project, 5366-21000-022-00D, “Small Grains Genetic Resource Management”. In the 2006-2007 RWA screening, evaluations were focused on a group of accessions that were previously evaluated with RWA biotype 1 by the group at Stillwater in the 1990s, but had not yet been evaluated with RWA biotype 2. These accessions originate from countries where resistance was identified in previous screenings (e.g., Iran, Afghanistan, Uzbekistan, Tajikistan, Turkmenistan, Uzbekistan, Kazakhstan, and Kyrgyzstan) though these accessions were chosen because they all were scored as susceptible (chlorosis score > 5, rolled leaf) in the Stillwater screenings. As shown previously with the Iranian landrace screening, independence of RWA biotype 1 and biotype 2 resistance is common and we thus expected to find useful biotype 2 resistance among the accessions in this collection. Of the total group of 1,987 accessions, we completed the screening on 1,584 accessions. About 122 of these accessions either did not germinate at all or yielded too few viable plants for reliable screening (four plants is considered to be a minimum). Of the remaining 1,462 accessions, effective resistance was identified with 57 accessions showing a chlorosis score = 2 or 3 and 11 of these showing a "Flat" leaf rolling score. Many other accessions were identified with moderate levels of resistance (chlorosis score = 4 or. 5)and these may be useful in future studies targeted at identifying "durable" resistance. Monitoring of activities in this agreement were accomplished by telephone and e-mail.