Recent Topics Posters
Eserman, Lauren , Brown, Alyssa , Miller, Richard E .
Reproductive isolation between two species of morning glories.
Species of Ipomoea section Pharbitis are typically morphologically distinct, exhibit reciprocal monophyly, and do not hybridize readily, making species delimitation clear. However, I. nil and I. hederacea are two closely allied members of sect. Pharbitis where species boundaries are less clear. Conflicting lines of evidence exist regarding the delimitation of these two species. Specifically, they have disjunct distributions, are morphologically similar with only a single synapomorphy (sepal curvature), and are not reciprocally monophyletic. Therefore, a controlled greenhouse crossing experiment was conducted to examine the degree of reproductive isolation between these species using two large-flowered and two medium-flowered populations of I. nil, three medium-flowered populations of I. hederacea, and one small-flowered population that can be considered either I. nil or I. hederacea based on different treatments of these species. Various measures of interfertility significantly correlate with geographic distance, style length, and corolla length but not with genetic distance, indicating an overall trend of greater interfertility with close geographic distance and similar flower size that does not necessarily depend on genetics. Furthermore, we found high crossability between populations of the same species with similar sized flowers and low crossability when crossing pairs were different species or had different-sized flowers, e.g. large-flowered I. nil populations are just as incompatible with smaller-flowered I. nil populations as they are between species. Therefore, crossability between I. nil and I. hederacea is highly dependent on both flower size and species.
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1 - Southeastern Louisiana University, Biological Sciences, 808 N. Pine Street Extension, Hammond, LA, 70402, USA
2 - Southeastern Louisiana University, Department of Biological Sciences, 808 N Pine St, Hammond, LA, 70402, USA
Presentation Type: Recent Topics Poster
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM