PHYLOGENY OF POACEAE SUBFAMILY POOIDEAE BASED ON CHLOROPLAST NDHF GENE-SEQUENCES

Forty-eight representatives of 12 tribes attributed to the subfamily P ooideae s.l, of grasses (Monocots) have been studied by sequencing the more variable 3' end of the chloroplast ndhF gene. Six representative s from 5 different tribes of Poaceae (Oryzeae, Streptogyneae, Bambusea e, Arundineae, Phareae) and from Joinvilleaceae were used as outgroups . Phylogenetic analyses of the data render a monophyletic Pooideae cla de and provide an evolutionary hypothesis for all its tribes (Poeae, A veneae, Bromeae, Triticeae, Brachypodieae, Meliceae, Stipeae, Lygeae, Nardeae, Diarrheneae, Brachyelytreae, Phaenospermatae). The subfamily is composed of two subsets of tribes, a basal group that includes six old lineages or satellite tribes, in which Brachyelytreae is the first diverging branch followed by the Lygeae/Nardeae clade, and a group of six more recently evolved tribes (Pooideae s.s.), in which the diverg ence of Diarrheneae antedates that of Brachypodieae, sister group to t he ''core pooids.'' The character changes found within the sequenced n ucleotide positions of the ndhF gene also have proven to be informativ e at lower hierarchical levels (genus and species) for some tribes. (C ) 1997 Academic Press.