Genetics and Partitioning for Biomass of Prairie Cordgrass Compared to Switchgrass on Marginal Cropland

Prairie cordgrass (Spartina pectinata Link) has potential as a bioenergy crop in poorly drained cropland in much of temperate North America. Our objectives were (1) describe morphological differences between two prairie cordgrass populations and switchgrass for biomass production and pattern of biomass accumulation in leaf and stem tissue, (2) estimate genetic variation for biomass production and other agronomic traits in a population of prairie cordgrass from South Dakota, and (3) increase knowledge of the impact of insects on biomass production of prairie cordgrass. On poorly drained cropland in South Dakota, a natural population of prairie cordgrass (SD CG) from South Dakota produced 75% more biomass than a natural population from North Dakota, and a selected population of prairie cordgrass produced >2 times the biomass of switchgrass. However, when prairie cordgrass was fed on by larvae of the four-lined borer [(Resapamea stipata (Morr.)], yield of the two species was similar. Prairie cordgrass had a lower frequency of reproductive tillers (RTRs) and larger leaves than switchgrass. SD CG had high genetic variation for disease resistance, moderate genetic variation for biomass yield, and low genetic variation for inflorescences m⁻². Seven out of 57 half-sib families from SD CG produced more biomass than “summer” switchgrass during a year with normal precipitation, whereas only one family did so during a drought year. RTR declined rapidly with stand age. The four-lined borer was identified as a serious threat to biomass production of prairie cordgrass in eastern South Dakota.