| Switchgrass (Panicum virgatum L.) is a warm-season perennial grass native to North America. The difference in biomass production between and within switchgrass ecotypes (upland and lowland) and populations due to genotype x environment interaction (GxE) has been documented. Breeding research for increased biomass production in switchgrass has been conducted on University research farms with prime farmland. This study aims to evaluate the agronomic performance of 14 cultivars and 45 high biomass producing clones of switchgrass in marginal vs. prime farmland. Additionally this study investigates the effects of increasing biodiversity (1 grass species, 3 grass species or 4 species-grass/legume combinations) on biomass production. The cultivars and biodiversity studies were seeded in 2008 and 2009 in six locations (Maryland, New Jersey, New York, Pennsylvania, South Dakota and Wisconsin) and three locations (New Jersey, New York, Pennsylvania), respectively, in paired fields (marginal vs. prime land). Each field had a nitrogen treatment 0 or 100 kg of N·ha -1·year-1. Stand establishment (% coverage), plant height (cm), tiller density (tillers·m-2) and dry biomass yield (Mg·ha-1) data was collected to determine agronomic performance. The clonal material was transplanted in 2009 in two locations (New Jersey and South Dakota). In addition to agronomic data collected, heading date, anthesis date (Julian date) and visual ratings for disease presence were recorded. Cultivars were shorter in marginal soils. For stand establishment and biomass yield, 50% of cultivars showed differences due to soil quality. For tiller density, 40% of the cultivars presented differences due to soil quality; some cultivars had higher tiller density in marginal soils. For the biodiversity study low diversity plots (one grass species) were not significantly different than yields of high diversity plots (four species-grass/legume). For the clone study, soil quality may have influenced a delay in flower initiation and other traits, such as plant height, etc. It was also observed that genotype may have been the most influential factor in tolerance to anthracnose ( Colletotrichum navitas) and rust (Puccinia emaculata). |
