Effects of Mechanical Scarification on Germination and Emergence of Switchgrass

Switchgrass, Panicum virsatum L., is a tall, perennial, warm-season, sod-forming species native to most of the United States east of the Rocky Mountains. It is an important species for livestock in the Great Plains, producine its greatest growth in the hot summer months when cool-season species are nonproductive. As it is native to the Great Plains region, it exhibits ecotypic adaptability and forage production potential over a wide range of environmental and growing conditions. Because of its rhizomatous growth habit and fibrous root system, it is also useful. for soil conservation purposes. One of the problems associated with establishing native erasses in artificial seedings is related to dormancy mechanisms in their seeds. Native species are adapted to endure environmental changes in nature by having seeds that remain dormant until specific conditions are met. As a result, artificially planting certain native species often results in poor stand establishment. Seeds that germinate and emerge shortly after planting have the benefit of better temperature and moisture conditions needed for seedling growth. Switchgrass, although easier to establish than certain other native species, often exhibits delayed and sporadic germination and emergence. The main objective of this study was to evaluate mechanical scarification (cylinder scarification) for reducing seed dormancy, and for increasing rate of germination and seedling emergence of switchgrass. Promotion of rapid and uniform germination with a dormancy breaking procedure that was simple and feasible for large lots of seed was a final goal. Age of seed, storage conditions, genetic background, and germination temperature were other factors evaluated for their influences on germination and emergence