Submitted to: Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 21, 2010
Publication Date: February 7, 2010
Repository URL: http://www.orau.gov/gtl2010/postedabstracts.htm
Citation: Zalapa, J., Casler, M.D., Kaeppler, S., De Leon, N., Tobias, C.M. 2010. EST-SSR Markers Discriminate Switchgrass Ecotypes. 2010 Genomic Science Contractor-Grantee and Knowledgebase Workshop. Available: www.orau.gov/gtl2010/postedabstracts.htm Technical Abstract: Switchgrass (Panicum virgatum) is an important crop for bioenergy feedstock development. It is native to North America, ranging from Mexico to Canada east of the 100th meridian and adapted to a wide range of habitats (e.g., tallgrass prairie, savanna riparian habitats, etc.). Switchgrass has a range of ploidy from 2n=2x=18 to 2n=12x=108 and two main ecotypes: upland and lowland. Our objective was to use EST-SSR markers to discriminate upland from lowland ecotypes, using broader set of cultivars and individuals per cultivar than has been previously investigated. Longer-term goals of these studies are: (1) to use DNA markers to assist in identifying and selecting parents for development of heterotic gene pools and hybrid cultivars in switchgrass, and (2) to identify hybrid or backcross genotypes of mixed upland and lowland parentage, both in breeding programs and in natural populations.Plants classified as upland or lowland, based on origin and phenotype, were completely separated by EST-SSR markers, with only two exceptions. Those two exceptions were plants that originated in the USDA-ARS breeding program at Madison, WI. The plants had been classified as lowland based on phenotype, but their phenotypic is actually intermediate between the extreme upland and lowland phenotypes: intermediate heading date, intermediate height, intermediate color, and intermediate tiller size and density. Although these two individuals were distinct from both upland and lowland phenotypes, based on marker data these clustered with the upland ecotypes. In summary, the EST-SSR markers used in this study were extremely effective at discriminating between upland and lowland ecotypes and at identifying the genetic origin for two plants of unknown origin.