Stottlemyer, Amy , Snow, Allison , Sweeney, Patricia , Miriti, Maria , Heaton, Emily .
Flowering phenology, ploidy,and fitness differences between cultivated and native switchgrass (Panicum virgatum L.): implications for future biofuel crops.
Switchgrass (Panicum virgatum L.) is a warm-season, C4North American perennial that has many advantages as a potential biofuel crop and could be planted on a large scale in the near future. However, very little research has examined the potential impact that mass plantings will have on wild populations. We examined the potential for crop-to-wild gene flow and associated fitness effects by studying ploidy levels, flowering phenology, fitness components, and volunteer establishment. We determined ploidy levels of wild populations in Ohio and Illinois. Eight populations were tetraploid (4x), one was octaploid (8x), and two had mixed ploidy. In 2008 and 2009, we planted two common garden experiments at Ohio State University, with plants from three wild Ohio populations and seven cultivars: Kanlow (4x), Advanced Kanlow (4x),Summer (4x), Shawnee (8x), Trailblazer (8x), and two Advanced Octaploid strains(8x). In 2010, we compared the growth and fecundity of two- and three-year-old plants. Flowering times of native biotypes and the cultivars overlapped, but the degree of overlap varied, with Kanlow-type plants flowering much later than the rest. Kanlow-type plants were taller and produced four times as many florets as native biotypes, while Kanlow and Summer produced twice the number of filled seeds as native biotypes. All other cultivars were similar to the native plants, except one Advanced Octaploid strain, which produced more shoots. We also examined characteristics of spontaneous volunteers growing in the common gardens in 2011. Ploidy and ecotype frequencies (lowland vs. upland) were similar between common garden plants and volunteers. Many of the volunteers examined in detail were derived from cultivars rather than native plants. Hybridization was also evident, as 48% of volunteers had mixed features between Kanlow and other biotypes and two were 8x lowland ecotypes, a combination not present in the parents. Volunteer flowering overlapped with all cultivated and native biotypes. Our results show that gene flow between cultivars and wild relatives is possible due to shared ploidy and overlapping flowering times. Certain cultivars with much higher fecundity, like Kanlow, might eventually become common in Ohio if they escape widely and become feral or hybridize with wild plants. Volunteer plants also could facilitate gene flow between cultivated and wild switchgrass. Future research should focus on whether mass plantings of new switchgrass cultivars could result in the displacement or dilution of local switchgrass genetic diversity or possible weed problems resulting from feral and crop-wild hybrid populations.
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1 - Ohio State University, EEO Biology, 300 Aronoff Laboratory, 318 W 12th Ave, Columbus, OH, 43210, USA
2 - Ohio State University, EEOB DEPT, 318 W. 12th Ave., COLUMBUS, OH, 43210-1293, USA
3 - Ohio State University, EEO Biology, 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, Department of Agronomy, 1403 Agronomy Hall, Ames, IA, 50011, USA
crop-wild gene flow
Presentation Type: Oral Paper:Papers for Topics
Location: Union C/Hyatt
Date: Tuesday, July 10th, 2012
Time: 11:00 AM