COMPARISON OF SWITCHGRASS (Panicum virgatum L.) GENOTYPES AS POTENTIAL ENERGY CROP

Seven genotypes of Panicum virgatum L., a perennial grass crop, were compared over two growing seasons in order to investigate potential biomass yield, its stability in time, and to assess nitrogen and ash content as characteristics detrimental to utilization in the energy chain. Crops were planted in May 2002, harvested in February 2003 for the first year; in February 2004 and in July 2003 + February 2004 for the second one. The two early, upland octaploid genotypes (Shawnee and Trailblazer) performed a lower yield associated to a lower moisture and to a higher ash content. The remaining five lowland tetraploids featured variable traits: NL 94-1, SL 93-3 and SL 94-1 had the best performances in terms of biomass yield and ash content; Alamo and Kanlow had an intermediate behaviour between them and the two octaploids. In the second year, the double harvest (summer + winter) showed a 50% yield increase with respect to the single one, associated to an undesirable peak in nitrogen and a...