2012 Annual Report 1a.Objectives (from AD-416): We will conduct fine mapping of the Rag2, Rag3, Rag4 genes for soybean aphid resistance with SNP markers. Also identify candidate genes and proteins for the Rag2 gene identified earlier by ARS. 1b.Approach (from AD-416): To develop SNP markers for soybean aphid resistance genes for marker assisted breeding for Rag2, Rag3, and Rag4 genes: SNP markers will be identified in the genomic regions of the aphid resistance genes using appropriate RIL mapping populations (already in hand) and near isogenic lines. The Solexa sequencing and Illumina genotyping platforms will be used for this objective/strategy. 3.Progress Report: Research developed the 4th 5th and 6th generations of back cross (BC) (BC4, BC5 and BC6) near-isogenic lines (NILs) of the Rag2 gene, conducted phenotypic characterization of more than 5000 NILs. The fine mapping of the Rag2 gene from PI 243540 will be completed by September 2012. Over the life time of the project, near-isogenic lines and recombinant inbred lines were developed. Researcher conducted phenotypic screenings of lines with the soybean aphids, designed experiments of aphid treatments and tissue collections for proteomic and Rag2 mapping studies. Please associated SCAs (3607-21000-05S, 06S and 07S). This project enhances/expands on objective 2B (Characterize and map aphid resistance genes in three soybean plant introductions) of the parent project by furthering fine mapping of the Rag2 gene from one of the three plant introductions.