Arakaki, Monica , Soltis, Douglas E. , Soltis, Pamela S. .
Use of microsatellites to examine intergeneric hybridization (Haageocereus x Espostoa), as well as population structure in Haageocereus (Cactaceae).
Haageocereus Backeb. is a shrubby columnar cactus largely restricted to the western slopes of the Peruvian Andes. As is true of the majority of genera in Tribe Trichocereeae, relationships within Haageocereus are poorly understood. Part of the taxonomic difficulty is the result of the occurrence of intermediate morphologies attributed to hybridization. Polyploidy is also suspected. These processes seem to be frequent in cacti but the relative importance of hybridization and polyploidy as speciation mechanisms in the group are not known. Although some of the species of Haageocereus cover wide geographic ranges, others are now restricted to areas as small as only one square km. The genus is considered vulnerable, and seven species as well as five subspecies have been classified under the IUCN as in danger of disappearance throughout all or a significant portion of their ranges. We are applying microsatellite markers designed for the genus to examine the amount of genetic diversity within and among populations of two rare and two widespread species of Haageocereus. We are also using these loci as a tool to validate three putative intergeneric hybrids identified by intermediacy in morphology (Haageocereus pseudomelanostele x Espostoa melanostele, H. pseudomelanostele ssp. carminiflorus x Espostoa lanata, and H. pseudomelanostele ssp. acanthocladus x Espostoa melanostele). These genetic data should contribute to the development of conservation strategies and will provide insights into the frequency of reticulate evolution in the genus.
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1 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA
2 - University of Florida, Florida Museum of Natatural History, Department Of Natatural Science, Gainesville, Florida, 32611-7800, USA
Presentation Type: Oral Paper
Date: Monday, August 15th, 2005
Time: 1:45 PM