|| Cassida, K. A., Muir, J. P., Hussey, M. A., Read, J. C., Venuto, B. C., Ocumpaugh, W. R.
||Optimizing biofuel production and quality from switchgrass (Panicum virgatum L.) may require matching of ecotype and morphological type to environments, particularly in southern regions. Nine genotypes from four combinations of ecotype and morphological switchgrass type were harvested from 1998 to 2000 in five sites across Texas, Arkansas, and Louisiana that varied in latitude and precipitation. An additive main effects and multiplicative interaction (AMMI) method was used to evaluate genotype X environment interaction (G x E) patterns for traits important to biofuel production. Compared with upland genotypes across all site-years, lowland genotypes had greater lignocellulose yields (3.26 vs. 7.40 Mg ha(-1)), greater removal rates of soil N (41 vs. 83 kg ha(-1)) and P (6 vs. 12 kg ha(-1)), greater concentrations of moisture (394 vs. 452 g kg(-1)) and cellulose (388 vs. 394 g kg(-1)), and lower concentrations of N (6.3 vs. 5.7 g kg(-1)) and ash (48 vs. 40 g kg(-1)). Compared with northern ecotypes, southern ecotypes had greater lignocellulose yields (4.95 vs. 6.85 Mg ha(-1)), greater removal rates of soil N (60 vs. 76 kg ha(-1)) and P (8 vs. 11 kg ha(-1)), greater moisture concentrations (417 vs. 445 g kg(-1)), and lower ash concentrations (45 vs. 40 g kg(-1)). Lignocellulose yield paralleled dry matter yield (DMY) patterns. Switchgrass biofuel production efforts in the south-central USA should focus on improving DMY of southern lowland genotypes to maximize lignocellulose yields, but management factors may be more effective in optimizing moisture, ash, and mineral concentrations for combustion.