Phylogenetic analysis of the cultivated and wild species of Phaseolus (Fabaceae)

The species of Phaseolus were exhaustively sampled for both ITS/5.8S DNA se quence and non-molecular data. With all related New World genera designated as outgroups, a phylogenetic analysis of combined data reveals a strongly supported monophyletic Phaseolus. Other well supported relationships includ e nine monophyletic species clades within Phaseolus, designated as the P. v ulgaris, P. filiformis, P. lunatus,P! polystachios, I! leptostachyus P! pau ciflorus, I! tuerckheimii, and I! pedicellatus groups, and I! microcarpus. Only the last of these is monotypic and consistently resolved in a sensitiv ity analysis as the earliest branch in the Phaseolus dade, though with poor bootstrap support. The five most commonly domesticated species in the genu s arise from within the I! vulgaris and P! lunatus groups. The "gene pools" traditionally recognized for the domesticated species I! vulgaris and P! l unatus are not detected with ITS sequence variation. This is in spite of a very high degree of inter- and intra-specific ITS sequence divergence in Ph aseolus.