Abstract Detail

Conservation Biology

Palik, Destiny [1], Snow, Allison [1], Sweeney, Patricia [2], Stottlemyer, Amy [3], Miriti, Maria [4], Heaton, Emily [5].

Relative Competitive Abilities of Cultivated vs. Wild Switchgrass (Panicum virgatum): Implications for New Biofuel Cultivars.

Native switchgrass (Panicum virgatum L.) is a leading candidate for cultivating perennial grasses for use as biofuels in the USA. To establish high-yielding monocultures requiring minimal management, the biofuel industry has focused on developing new switchgrass cultivars, including new transgenic varieties, with increased biomass production and greater tolerance of abiotic stress. However, many attributes desired for biomass production are also typical of invasive plants, so cultivating plants with these traits on very large areas may have implications for potential invasiveness. To begin to address these concerns, we assessed the competitive abilities of four current switchgrass cultivars and two local wild accessions in Ohio and Iowa, respectively, using a common garden design in each state in 2011. Plants were grown under three levels of competition: with native little bluestem (Schizachyrium scoparium), weedy brome grass (Bromus inermis), or without competition. Competition treatments involved surrounding each switchgrass plant with 6 competitors in Ohio or 3 competitors in Iowa (fewer were available due to logistical problems). At both sites, the Kanlow and Advanced Kanlow cultivars were taller than wild biotypes, which were similar in height to Blackwell and Sunburst; competition had no effect on plant height in either state. In contrast, competition typically resulted in fewer shoots per plant across biotypes in Ohio and had a smaller effect on shoot number in Iowa, where fewer competitors were used. Across all treatments at both sites, wild plants produced as many or more shoots than the cultivars. In the absence of competition, Kanlow and Advanced Kanlow generally produced similar numbers of shoots as the two wild populations at both sites, while Blackwell and Sunburst produced fewer. With competition, few differences among the six biotypes were statistically significant. Therefore, our results to date suggest that cultivars are not better competitors than wild biotypes in terms of shoot number. In 2012, we will evaluate second-year plants to test for similar patterns in growth and fecundity. Our previous research showed that Kanlow and Advanced Kanlow produced about twice as many seeds per plant as wild biotypes in Ohio. Thus, our current hypothesis is that the fecundity of cultivars that establish volunteer populations can exceed that of native switchgrass, depending on the cultivar, but clonal competition is not expected to provide an advantage relative to local genotypes. Further research by our group will focus on fitness differences between wild and cultivated switchgrass and implications for projected population growth rates.

Broader Impacts:

1 - Ohio State University, EEOB DEPT, 318 W. 12th Ave., COLUMBUS, OH, 43210-1293, USA
2 - Ohio State University, EEO Biology, 318 W 12th Ave, Columbus, OH, 43210, USA
3 - Ohio State University, EEO Biology, 300 Aronoff Laboratory, 318 W 12th Ave, Columbus, OH, 43210, USA
4 - Ohio State University, Room 300 Aronoff Laboratory, 318 W. 12th Avenue, Columbus, OH, 43210, USA
5 - Iowa State University, Dept. of Agronomy, 2101 Agronomy Hall, Iowa State University, Ames, IA, 50011, USA

Keywords:
Panicum virgatum
biofuels
tallgrass prairie
grass competition.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM
Number: PCB006
Abstract ID:640