Submitted to: Forage and Grazinglands
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/1/2010
Publication Date: 4/27/2010
Publication URL: http://www.plantmanagementnetwork.org/sub/fg/research/2010/switchgrass/
Citation: Sanderson, M.A. 2010. Long-term persistence of synthetic populations of a lowland switchgrass ecotype and the cultivar Cave-in-Rock. Forage and Grazinglands. Available: http://www.plantmanagementnetwork.org/sub/fg/research/2010/switchgrass/. Interpretive Summary: Switchgrass, a warm-season perennial grass native to much of North America, has received extraordinary attention as a candidate cellulosic bioenergy crop. Long-term data on the persistence and yield of alternative varieties and ecotypes of switchgrass are limited for the northeastern USA. An existing field-plot study provided an opportunity to evaluate the long-term persistence (20 years) of a standard switchgrass variety (Cave-in-Rock) compared with germplasm (six synthetic switchgrass populations) used in the development of recently released varieties (‘BoMaster’ and ‘Performer’) specifically developed for biomass energy production. The field-plot experiment was established in 1989 and continued through 2009. After 20 years of management there were no significant differences among switchgrass entries for plant height, tiller density, or biomass yield. The results from this long-term evaluation of the yield and persistence of these switchgrass populations indicate that southerly adapted lowland cultivars could provide diversity in cultivar choices for switchgrass bioenergy production in the northeastern USA.
Technical Abstract: Upland cultivars of switchgrass (Panicum virgatum L.), such as ‘Cave-in-Rock’, are most frequently recommended for the northeastern USA. Lowland ecotypes typically originate from more southerly locations and have coarser stems than upland ecotypes. Long-term data on the persistence and yield of lowland ecotypes are limited for the northeastern USA. In this study, I report the yields and tiller densities of synthetic populations of lowland germplasm compared with Cave-in-Rock after 20 years of management. In 1989, as part of a germplasm evaluation trial, six synthetic switchgrass populations (NCI-16, NCII-16, NCIII-16, NCII-4, NCIII-4, and NCII-8; progenitors of the recently released cultivars BoMaster and Peformer) along with Cave-in-Rock were established in replicated small-plots at Rock Spring, PA. At the end of the germplasm evaluation in 1994, the plots were maintained with reduced management until 2008. In May 2008, the plots were reactivated and N fertilizer was applied at 100 kg ha**-1. Plant height, tiller density, and biomass yield were determined in November of 2008 and 2009. There were no significant differences among switchgrass populations and Cave-in-Rock for plant height, tiller density, or biomass yield. Although the synthetic populations are mainly adapted to the southeastern USA, these data suggest that under bioenergy crop management (one harvest annually) plant material developed from these populations should persist as far north as central Pennsylvania.