Increasing Legume Grazing for Higher Beef Gain on Pastures: An Improved High-Tannin Birdsfoot Trefoil Cultivar with Trans-Regional Potential.

This is a first report on a NIFA grant (Award No. 2013-67013-21408) that was funded during the 2013 funding cycle. This collaborative effort involves eight scientists from seven academic institutions. Birdsfoot trefoil (BFT), a non-bloating forage legume, has potential to improve sustainability of pasture systems in the Eastern Transition Zone (ETZ) of the USA. Tannins in BFT can improve protein utilization efficiency and reduce methane emissions and nitrogen excretion by grazing animals. This proposal combines the expertise of a plant breeder with that of forage management researchers and extension specialists. Our ultimate goal is to develop a trans-regional BFT cultivar with high condensed-tannin concentration and wide geographic adaptation with longer stand life than existing cultivars. APPROACH 1 begins with a collection of old cultivars that have not been marketed for a number of years and ends with the creation of five synthetic populations ready to undergo seed yield testing prior to release. Selection environments will include three in the ETZ, and one each in the Upper Midwest (UMW) and Intermountain West (IW). At each location, BFT will be evaluated for up to four (or 4) years in mixed stands with tall fescue. Selection criteria will be survival, plant size, and tannin content. One synthetic population will be developed at each location. APPROACH 2 will utilize approximately 25% of the USDA-NPGS germplasm accessions. Accessions will undergo two cycles of recurrent selection for survival, tannin content, growth habit, and seed mass and yield at a site in each of the regions of intended production, viz. ETZ, UMW and IW. End products will be three pre-breeding populations that may then be incorporated into future cultivar development programs.