Production of biomass feedstock crops could produce substantial environmental benefits, but these will be sharply reduced if these crops become invasive. Switchgrass (Panicum virgatum L.) is being bred for biomass production; these selective efforts may enhance invasive traits. To inform the assessment of invasive risk, undomesticated switchgrass strains were used as a baseline for comparison with strains bred for biomass production. In a three-year field experiment, we compared juvenile plant densities and survival, persistence of established plants, and aboveground biomass between selectively bred (cultivar) and undomesticated switchgrass strains. Cultivars had modestly greater third-year biomass and first-year plant densities than commercial ecotypes but lower survival and persistence; consequently, third-year plant densities did not significantly differ between cultivars and commercial ecotypes. Higher initial establishment and subsequent self-thinning in cultivars resulted in stands that were similar to those of commercial ecotypes. Therefore, our results do not suggest that the breeding of current cultivars of switchgrass enhanced juvenile and young-stand traits associated with invasiveness. Because biomass yields were not greatly different between cultivars and commercial ecotypes, use of the latter in biomass grasslands could provide functional benefits, including an enhanced habitat for native biodiversity and reduced pathogen loads, without incurring large losses in biomass production.
Bibliographical noteFunding Information:
Funding: This work was supported by the National Science Foundation (DGE 0653827), Garden Clubs of America (Fellowship in Ecological Restoration), University of Minnesota-Twin Cities (Graduate School Fellowship, Carolyn Crosby Fund Fellowship), and Bell Museum of Natural History (Dayton Fund Fellowship) awards to SF.
This work was supported by the National Science Foundation (DGE 0653827), Garden Clubs of America (Fellowship in Ecological Restoration), University of Minnesota-Twin Cities (Graduate School Fellowship, Carolyn Crosby Fund Fellowship), and Bell Museum of Natural History (Dayton Fund Fellowship) awards to SF. We are grateful to Tom Holm, Holly Lammert, Jesse Mack, Mike McClellan, Ron Nelson, Steve Poppe, Bob Schafer, and Tom Warnke for their assistance and to D.L. Larson and N.O. Anderson for constructive comments. Arvid Boe generously provided the ?Summer? switchgrass seed used in this experiment. Assistant editor Bella Yu and two anonymous reviewers provided constructive comments that improved the quality of this manuscript. We acknowledge that the lands on which this research was conducted are in the traditional territories of the Bdewakantunwan, Wahpetunwan, and Wahpekute Dakota, and the Anishinabe, and we acknowledge with respect their cultures, histories, and contemporary lives, realized despite ongoing colonialism and oppression.
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Bioenergy risk assessment
- Native bioenergy crop
- Panicum virgatum
- Population source
- Weed risk assessment