2005 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between ARS and North Dakota State University, Department of Plant Sciences. Additional details of research can be found in the report for the parent project 5442-22000-027-00D Enhancement of Sunflower Germplasm Diversity through the Use of Wild Species and Genome Characterization. Accessions of three wild annual Helianthus exilis, three H. schweinitzii, one H. verticillatus, one H. angustifolius, and one H. californicus were identified to be resistant to Sclerotinia stem rot, and were used for crosses with stem-rot tolerant line HA 410. Identified Sclerotinia resistant wild perennial Helianthus accessions of H. maximiliani and H. nutallii were established in the greenhouse, and were used for crosses with head-rot tolerant line HA 441. Successful F1 progeny for stem-rot resistance were inoculated and the surviving plants are being backcrossed with HA 410.