Developing Improved Legume Cover Crops.

Cover crops are used in cropping systems to conserve soil and water resources; to suppress weeds; and to aid in plant nutrient management.  Legume cover crops have the added ability to supply nitrogen to the cropping system through symbiotic nitrogen fixation. Breeding programs are in progress at Overton, TX to improve cover crop traits in berseem clover (T. alexandrinum L.), crimson clover (T. incarnatum L.), forage cowpea (Vigna unguiculata Walp.), and lablab bean (Lablab purpureus [L.] Sweet).  In the annual clovers, experimental lines are under development with improved winter growth, increased cold tolerance and low hard seed.  In the forage cowpea and lablab bean programs, the objectives are drought tolerance; full season growth and seed production.  Winter survival and biomass production are critical traits for any winter cover crop and these will be core traits for new winter pea (Pisum spp.) cultivars developed at Pullman, WA and for new hairy vetch (Vicia villosa Roth) cultivars developed at Madison, WI.