Objective:
1) To identify the optimum selection technique to identify the best performing switchgrass plants (with higher nitrogen use efficiency [NUE]) on marginal land and to identify germplasm of switchgrass that performs best on marginal land in each region; 2) Identify cultivars of switchgrass that perform best on marginal land in each region and identify cultivars that may have broader adaptation across several locations on marginal land; 3) Determine the biomass production of C4 grass and legume mixtures vs. C4 grass monocultures on marginal land in each adaptation region; and 4) Develop new cultivars with improved biomass production for biofuels on marginal land in each adaptation region.

Approach:
Switchgrass cultivars and half-sib families will be evaluated at Hancock and Arlington, WI. The two locations will represent prime farmland and marginal farmland for growing switchgrass as a bioenergy crop. Plots will be planted in 2008 and harvested in 2009-2011.