ALICE, LAWRENCE A.* AND DUSTIN K. CONOVER. Department of Biology, Biotechnology Center, and Center for Biodiversity Studies, Western Kentucky University, Bowling Green, KY 42101. - Systematics of Rubus (Rosoideae; Rosaceae) based on nuclear ribosomal ITS and chloroplast trnK intron DNA sequences.
We used DNA sequences from the nuclear ribosomal internal transcribed
spacer (ITS) region and the chloroplast trnK intron, including
the matK gene, to test monophyly and infer phylogenetic
relationships of Rubus and its subgenera. Our ITS and
trnK data sets include 17 species representing eight of the 12
Rubus subgenera, Dalibarda repens, and using
Fallugia as an outgroup. Separate and combined parsimony
analyses suggest that Rubus is paraphyletic because
Dalibarda nests within it although bootstrap support is low. A
clade including 12 of the species (excluding Dalibarda repens,
Rubus pedatus, R. chamaemorus, R. deliciosus, and
R. odoratus) is apparent in both the ITS and trnK
analyses, and gains strong support (95%) in the combined analysis.
This suggests that unarmed and primarily herbaceous, simple-leaved
species are ancestral in Rubus. Within the clade of 12
species, several relationships are well supported in both separate and
combined analyses. One includes four species of North American
blackberries (subgenus Rubus) and another is the relationship
between R. crataegifolius of subg. Idaeobatus and R.
trifidus of subg. Anoplobatus. These results indicate that
subg. Anoplobatus is polyphyletic because R. trifidus is
more closely related to R. crataegifolius than to R.
odoratus + R. deliciosus which form part of the basal
complex in Rubus.
Key words: ITS, phylogeny, Rosaceae, Rubus, systematics, trnK