2005 Annual Report 4d.Progress report. This report documents research conducted under a specific cooperative agreement between ARS and the LSU AgCenter, Baton Rouge, LA. Additional details of the research can be found in the report of the parent project 6218-21410-002-00D, Develop and Manage Forage Resources for a Sustainable Agriculture. Legumes offer potential for forage and biomass production, but they also can provide nitrogen to forage and biomass production systems, through rhizobial fixation of atmospheric nitrogen. Legumes that are adapted to harsh conditions or that can tolerate broadleaf herbicides offer advantages for use in mixed grass-legume forage or biomass production systems. White clover plants selected for tolerance to the herbicide 'Plateau' were evaluated in Oklahoma and Louisiana and were found to lack significantly improved tolerance to this herbicide. White clover germplasm selected for tolerance to the commonly used pasture herbicide Grazon are currently being evaluated at El Reno, Oklahoma, and Winnsboro, Louisiana. Three experimental lines of alfalfa are being evaluated for long-term persistence, biomass production and nutrient characteristics in Oklahoma and Louisiana. Two of the lines were demonstrated to be somewhat more tolerant of leafhopper infestation than the control varieties.