Segovia, Claudia , Quijia, Paulina , Soltis, Douglas , Soltis, Pamela .
Cytogeography of Four Species of Polylepis (Rosaceae) in Ecuador and its Relevance to Conservation of Andean Forests.
Polylepis (Rosaceae) comprises28 species from the Andean Highland Ecosystems, with species distributed from Venezuela to northern Argentina. Interspecific relationships have been unclear due to presumed hybridization and polyploidy. As part of a larger project to understand evolutionary patterns and processes in Polylepis, ploidy has been analyzed to determine species boundaries,detect evidence of hybridization, and ascertain whether geographical patterns are associated with differences in ploidy in four species from Ecuador. We summarized 202 chromosome counts for four species of Polylepis throughout most of their ranges. Polyploids based on x = 7 are widely distributed in these species. Multiple cytotypes exist in the four species analyzed, mostly as hexaploids, nonaploids, and decaploids. Ploidy variation was evident in the Sericeae group species [P. pauta (2n = 62, 70, 80) and P.sericea (2n = 42, 62, 80)], along with occasional aneuploidy, where nonaploids and decaploids of both species have similar geographical distributions. Our data also suggest that a hybrid swarm between P. pauta and P. sericea could exist in the northern area, and a careful review of the taxonomy of these species in Ecuador is needed. Widespread polyploids of these two species are likely derivatives following secondary contact among translocated and natural populations during the last decade. The species belonging to the Incana complex have ploidy variation between hexaploids and dodecaploids. Polylepis incana shows a constant hexaploid chromosome number (2n=42 ).On the other hand, the presence of at least three cytotypes (2n=62, 70, 82), along with low-frequency aneuploid variants of these numbers, in P. racemosa populations, an exotic species from Peru, provides evidence of possibly more than one introduction into Ecuador since the initial event in the 1980s. This information is fundamental for conservation and reforestation policy of Andean Forests in Ecuador.[These results suggest that polyploidy played an important role in this group and are consistent with the confusing history of this genus, with hybridization,polyploidy, and aneuploidy blurring species boundaries.
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1 - University Of Florida, Florida Museum Of Natural History, Dickinson Hall, Gainesville, FL, 32611, USA
2 - Escuela Politecnica del Ejercito, Ciencias de la Vida, Av. General ruminahui s/n, Sangolqui, Ecuador
3 - University Of Florida, Department Of Botany, 220 BARTRAM HALL, Gainesville, FL, 32611, USA
4 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964
Presentation Type: Poster:Posters for Topics
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM