Systematics/Phytogeography / Taxonomie/ Section
Achigan-Dako, Enoch G. , Blattner, Frank R. .
Phylogenetic evaluation of Cucurbitaceae by nrDNA ITS sequences with special emphasis on the tribe Benincaseae.
The Cucurbitaceae are divided in two subfamilies: Zanonioideae and Cucurbitoideae. In a recent classification eleven tribes were recognized for both subfamilies based on seed-coat anatomy. Benincaseae, with 40 genera in two subtribes (Benincasinae and Cucumerinae) is the largest tribe of Cucurbitaceae. The tribe, abundantly present in tropical West Africa, includes many worldwide economically important species. Despite the economical and numerical importance of this tribe few studies focused on the analysis of phylogenetic relationships within the tribe. Up to now there is no conclusive evidence whether molecular data support the seed-coat based classification. To elucidate evolutionary trends within the tribe we report the phylogeny of most West African cucurbit taxa, including 122 nrDNA internal transcribed spacer region (ITS) sequences of 65 species and subspecies covering most species of Benincaseae. Taxa used include Benincaseae (40), Joliffeae (6), Coniandreae (3), Cucurbitaea (6), Cycyaea (4), Luffaea (2), and one taxon of Trichosantheae as outgroup. Phenetic, cladistic, and model-based analyses revealed the monophyly of the Benincaseae. However, the subdivision of the tribe into Cucumerinae and Benincasinea is not supported, as most species of Cucumerinae occur throughout the clade. Moreover, the genus Cucumis appeared paraphyletic, embedding all accessions of Mukia medaraspatens. Oreocyse africana, however, felt outside Cucumis in contrast to previous results. Our data support the elevation of Luffinae to tribal rank, which did not show any sister relationship with the Benincaseae. From our data we argue that a revision of the classification of Benincaseae is needed including all members.
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1 - Institute of Plant Genetics and Crop Research (IPK), Taxonomy & Evol. Biology, Gatersleben, D-06466, Germany
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM