Registration of ‘Empire’ big bluestem

Abstract

Empire' (Reg. no. CV-18, PI 700112) big bluestem (Andropogon gerardii Vitman) is a 54-clone synthetic selected for high biomass yield. Empire is broadly adapted to USDA hardiness zones 3-7, ranging from the Great Plains to the eastern United States. Although Empire was developed as a high-biomass cultivar for use in establishing perennial biomass production for conversion to bioenergy, it has a heading date similar to many other big bluestem cultivars, suggesting that it could be used as a forage crop as well for either hay or pasture production. Under an optimal singleharvest biomass production management, Empire ranked 1st in biomass yield for 8 of 12 locations in multiple-year trials averaged over a total of 40 environments (locationtrial-years). Biomass yield of Empire, averaged over 12 locations, was 30% higher than 'Goldmine', 46% higher than 'Champ', and 52% higher than 'Bonanza'. Ground cover of Empire was slightly higher than for most check cultivars, averaging 80% across all 12 locations. Empire is broadly adapted to USDA hardiness zones 3-6, extending from the Great Plains to the eastern United States and was released to the public by the USDA Agricultural Research Service in 2021.