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

CIALDELLA, A.; ROMASCHENKO, K.; SEDE, S.; PETERSON P.; SORENG, R.; ZULOAGA, F.; MORRONE, O.

La Serena, Chile

Congreso; X Congreso Latinoamericano de Botánica; 2010

Asociación Latinoamericana de Botánica

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. Phylogenetic relationships of some genera of the Stipeae were previously analyzed using cpDNA and morphology; in these studies the sampling of Nassella species was scarce. The aim of this work 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. As a result, the 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, severalwell-supported small clades were recovered. These results are supported by several morphological characters, mainly related with anthecia structures. These results provide good support for re-evaluating the taxonomic status of Nassella, Amelichloa and Jarava p.p. within the tribe Stipeae.