Weems, Kimberly O. , Byers, Diane .
The Effects of Inbreeding on Chamaecrista fasciculata †from a Small Prairie Fragment.
Prairie habitat today in Illinois is mostly found in small isolated patches, between corn and soybean fields. Remaining native prairie species occur in small-sized and isolated populations. Small population size is predicted by evolutionary theory to lead to lower genetic diversity, increased genetic load, and increased inbreeding compared to a large population. Furthermore, inbreeding may increase expression of genetic load, resulting in a decline in survivorship and reproduction in the small populations. Using a small population of ¬†Chamaecrista fasciculata (a native prairie species), we are experimentally testing if inbred plants have lower survivorship and fruit production compared to outcrossed individuals. Our focus for this study is a population in Weston Cemetery Prairie, a remnant small tallgrass prairie (2.02HA). We are comparing the offspring from three types of crosses: selfing, outcross within population and outcross between populations. We used a large population in a very large tallgrass prairie (Goose Lake State Park) as the pollen donors for outcross between populations. To compare their response to stress, we grew the plants in competitive and noncompetitive treatments. For the noncompetitive treatment, each plant was grown alone. For the competitive treatment, a target plant and two competitors from the same maternal plant but of the different cross types were grown in the same pot. Competition treatments will better test expression of inbreeding depression which may not be expressed without a form of stress. The plants were assessed for rate of germination, flowering phenology, growth, biomass, and seed and fruit production. Early analysis indicates the offspring from the selfed crosses are slower to germinate and grow slower than plants from either type of outcross. The inbreeding depression found in this isolated population is consistent with our expectations of genetic load in small populations.
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1 - Illinois State Univeristy, Biological Sciences, 11642 Liberty Ln, Plainfield, il, 60585, USA
2 - Illinois State University, School of Biological Sciences, Campus Box 4120, Normal, IL, 61790-4120, USA
Presentation Type: Poster:Posters for Sections
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM