Long-term Persistence of Synthetic Populations of a Lowland Switchgrass Ecotype and the Cultivar Cave-in-Rock

Abstract

Upland cultivars of switchgrass (Panicum virgatum L.), such as ‘Cave-in-Rock,’ often are recommended for the northeastern USA. Lowland ecotypes typically originate from more southerly locations than upland ecotypes. Long-term data on the persistence and yield of lowland ecotypes are limited for the northeastern USA. Here, I report the yields, plant heights, and tiller densities of synthetic populations of lowland germplasm compared with Cave-in-Rock after 20 years of management. In 1989, as part of an evaluation trial, six synthetic switchgrass populations (NCI-16, NCII-16, NCIII-16, NCII-4, NCIII-4, and NCII-8 − progenitors of the cultivars BoMaster and Peformer) along with Cave-in-Rock were planted in replicated plots at Rock Spring, PA. After the germplasm evaluation in 1994, the plots were maintained with limited management until 2008. In May 2008, the plots were reactivated and N fertilizer was applied at 90 lb/acre. Plant height, tiller density, and biomass yield were determined in November of 2008 and 2009. Cave-in-Rock did not differ from the synthetic populations in 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.