Abstract Detail

Ericaceae: Systematics, Ecology and Evolution

Gillespie, Emily [1], Kron, Kathleen [2].

Evidence for Rapid Diversification within the Azaleas (Rhododendron section Pentanthera).

The azaleas (Rhododendron subgenus Pentanthera section Pentanthera) are a group of 17 mostly North American deciduous shrubs. Azaleas are collectively important horticultural and hybridization targets whose evolutionary history is unclear. Fourteen of these species are extremely closely related based on overall morphology, and are concentrated in the southeastern United States. Three other species appear to be slightly more distantly related and occur in the Pacific Northwest United States, the Caucasus, and in eastern Asia. Historically, groups of species were recognized on the basis of corolla color (orange, pink or white groups) or particular features such as the presence or absence of a corolla blotch. Attempts over the past decade to use molecular datasets of up to five gene regions have failed to demonstrate that those groupings are monophyletic, but many nodes exhibited low statistical support. Here, we report on progress toward estimating the phylogenetic relationships of the Pentanthera azaleas using a dataset comprised of 11 chloroplast genes ranging from coding regions to intergenic spacers and 4 nuclear genes. Every azalea species from section Pentanthera is sampled, along with 10 Rhododendron outgroup taxa representing all subgenera and four outgroup representatives from other Ericoidean tribes. All major modes of analyses are employed (Maximum Parsimony, Maximum Likelihood, and Bayesian Inference) as well as specific efforts to maximize signal and minimize noise. Maximizing the phylogenetic utility of the current dataset of 15 markers permits the best estimation of the phylogeny while also potentially informing the necessary next steps using other technologies and platforms.

1 - Marshall University, Biological Sciences, One John Marshall Drive, Huntington, WV, 25755, United States
2 - Wake Forest University, Biology, Box 7325 Reynolda Station, Winston-Salem, NC, 27109, USA

Keywords:
Ericaceae
Rhododendron
Azalea
Pentanthera
Rapid radiation.

Presentation Type: Colloquium Presentations
Session: C07b, Ericaceae: Systematics, Ecology, and Evolution Part 2
Location: 114/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 4:00 PM
Number: C07b010
Abstract ID:507
Candidate for Awards:None