Efficacy of Current Breeding Programs to Improve North American Native Grass Species for Forage and Conservation Use in the South Eastern United States

Efficacy of Current Breeding Programs to Improve North American Native Grass Species for Forage and Conservation Use in the South Eastern United States

North American native warm-season grasses (NWSG) have received much attention over the last 25 years for their ability to persist under hot, dry conditions and thrive in marginal soils. Native warm season grasses are believed to have been growing on the central and south eastern plains of the United States since the Holocene era (between 11,500 and 2,000 years BP) thus the Southeast is the centre of diversity for these grasses (Casler, 2012). Modern production of many species has been slow to evolve due to inherent dormancy characteristics that hinder germination and establishment. With increased research, many species have shown promise for use as forage and hay crops, pasture, wildlife habitat and in land reclamation sites.

Native warm-season perennial grasses are slow to establish, making the seedlings poor competitors with weeds, especially weedy annual grasses. This establishment lag is due largely to seed dormancy, an important obstacle to the domestic cultivation of these grasses. Seed dormancy is present in all native grass species and provides a selective advantage under varying environmental conditions. The advantage of seed dormancy insures that some seed will remain viable, but not germinate under environmentally favourable conditions. All NWSG do not exhibit the same types or levels of dormancy, nor do they maintain their dormancies with the same severity (Chancellor, 1984).