Phylogenetic analysis of Nassella and allied genera (Poaceae-Pooideae-Stipeae) based on nuclear and chloroplast markers

CIALDELLA A.M. ; ROMASCHENKOO KK ; SEDE, S.M. ; PETERSON PP ; SORENG, R. ; ZULOAGA FO ; MORRONE O

La Serena

Congreso; X Congreso Latinoamericano de Botánica; 2010

Phylogenetic analysis of Nassella and allied genera (Poaceae-Pooideae-Stipeae) based on nuclear and chloroplast markers   Cialdella AM1, Romaschenko K2, Sede SM1, Peterson P2, Soreng R2, Zuloaga FO1 & Morrone O1   1. Instituto de Botánica Darwinion. Labardén 200, CC 22, B1642HYD - San Isidro-Argentina 2. Department of Botany, MRC-166 National Museum of Natural History -Smithsonian Institution P.O. Box 37012 Washington, DC 20013-7012   mail corresponding author   Nassella is one of the largest 28 core genera of the tribe Stipeae, with nearly 115 species occurring in America together with Achnatherum, Aciachne, Amelichloa, Anatherostipa, Hesperostipa, Jarava, Ortachne, Oryzopsis, Pappostipa, Piptatherum, Piptochaetium, and Ptilagrostis. The phylogenetic relationships of a few genera within the tribe Stipeae were investigated using cpDNA and morphology, although the sampling of Nassella species was scarse in all studies. The aim of this study is to corroborate the hypothesis of polyphyly of Nassella and to elucidate the relationships with Amelichloa and Jarava p.p. Individual and combined analyses of nrDNA ETS and cpDNA trnL-T regions were conducted using parsimony. The hypothesis of monophyly of Nassella was rejected in all analysis. Both Jarava and Amelichloa were nested within Nassella, rendering the genus paraphyletic. Although basal relationships are not well resolved, several well-supported small clades were recovered. The results are supported by several morphological characters, mainly from the anthecium. These results together with morphological data provide good support for re-evaluating the taxonomic status of Nassella, Amelichloa and Jarava p.p. within the tribe Stipeae.