Abstract Detail

Ecological Section

Palik, Destiny [1], Snow, Allison [1], Stottlemyer, Amy [1], Miriti, Maria [1], Heaton, Emily [2].

Responses of Cultivated and Wild Switchgrass (Panicum virgatum) to Competition: Implications for New Biofuel Cultivars.

The ongoing breeding of perennial grasses such as switchgrass (Panicum virgatum) for use as biofuel crops has raised concerns about the potential invasiveness of new biofuel cultivars. Indeed, many attributes desired for biomass production (e.g., high biomass and increased tolerance to abiotic stress) are also typical of highly competitive invasive plants. If biofuel crops are planted on millions of acres as expected, progeny from these plants may be able to survive and hybridize with wild relatives. The goal of this research was to assess the relative growth of four switchgrass cultivars and two local wild accessions, for a total of six biotypes, under three levels of competition. From 2011-2012, we conducted factorial-design, common garden experiments in Ohio and Iowa. Very similar results were obtained from both experiments, so only the Ohio data are described below. Competition treatments included either no competition or six competitor plants spaced equidistant around a focal switchgrass plant. Two competitors were used separately: native little bluestem (Schizochyrium scoparium), which had a moderate effect on growth, or weedy brome grass (Bromus inermis), which strongly inhibited the focal plant’s growth. In 2012, the height, aboveground biomass, and onset of flowering differed significantly among biotypes and competition treatments, but interactions between these two factors were not significant. Kanlow and Advanced Kanlow cultivars consistently grew taller, produced more biomass, and flowered later than all other biotypes at each level of competition. These two biotypes produced 65-86% more biomass than wild plants when data were averaged across competition treatments. In contrast, wild biotypes were comparable in height and biomass to Blackwell and Sunburst cultivars, showing few significant differences. In terms of total shoot production, switchgrass biotypes differed in their response to competition; relatively modest differences between native biotypes and the cultivars were seen only in plots without competition. Total shoot number was highly correlated with the number of flowering shoots, and estimates of seed production per plant are in progress. In summary, Kanlow and Advanced Kanlow biotypes were much larger than native switchgrass in both states, regardless of competition treatment, and this may translate into stronger competitive effects on neighboring vegetation. Therefore these cultivars may become more abundant than wild biotypes over time, depending on local propagule pressure and opportunities for establishment. In contrast, Blackwell and Sunburst were more similar to wild biotypes in this study and may be less competitive than Kanlow or Advanced Kanlow on a per capita basis.

Broader Impacts:

1 - The Ohio State University, Evolution, Ecology and Organismal Biology, 318 W. 12th Ave, Columbus, OH, 43210, USA
2 - Iowa State University, Department of Agronomy, Ames, IA, 50011, USA

Keywords:
Switchgrass
Biofuels.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:45 PM
Number: PEC022
Abstract ID:597
Candidate for Awards:Ecological Section Best Graduate Student Poster