The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Tuesday, January 29, 2008
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Genetic variation within genotypes of two native grass species after two generations of greenhouse seed source improvement
Karin E. Bergum1, Ann L. Hild1, Brian A. Mealor2, and Thomas Smith3. (1) Department of Renewable Resources, University of Wyoming, Box 3354, Laramie, WY 82071-3354, (2) The Nature Conservancy in Wyoming, 258 Main St., Suite 200, Lander, WY 82520, (3) U.S. Army Corps of Engineers, ERDC-CERL, P.O. Box 9005, Champaign, IL 61826
The capability of native grass populations to exploit patchy environments, survive disturbance events, and adjust to novel environments is partially derived from their genetic variation. However, most restoration projects do not monitor baseline native genetic diversity of native populations to document losses of genetic diversity over time. Because some native populations persist within weed invasions, their resilience provides great potential as seed sources for restoration. While greater genetic variability may increase their potential to adapt to a variety of sites, restriction in genetic variety may occur because of selection for competitive ability. This study examines the genetic variation of maternal genotypes (G0) of Sporobolus airoides and Hesperostipa comata derived from within and outside exotic invasions, after two generations (G2) of greenhouse propagation. Maternal plants were collected in 2003 from areas invaded by Acroptilon repens and adjacent noninvaded areas and were grown in greenhouse conditions. Seed collected from these accessions (G1) was grown in greenhouse conditions in 2005-2007 and subsequent seed production (G2) was germinated for genetic assessments. Leaf material from the three generations was collected to develop genetic profiles of the three generations. Genetic polymorphism, (variation in a population’s DNA) was examined using amplified fragment length polymorphism (AFLP) markers to determine heritability of genotypes, prevalence of out-crossing, and impacts of inadvertent selection. Our results suggest that differences in genetic variability occur between generations. These results reflect the importance of understanding whether specific genotypes are genetically conserved in the process of obtaining improved seed sources for restoration. Future studies should examine whether genetic differences within and among genotypes and generations correlate with increased competitiveness, long term survival and successful establishment in restoration settings. Determining a genetic baseline is a crucial first step in genetic conservation of restoration seed sources.