ABSTRACT--Four
molecular data sets are available for the diploid intersterile genera
of
the cereal grain tribe Triticeae, and there are numerous differences
among
the four published trees. All six pairwise combinations of data sets
were
examined using tree comparisons, the incongruence length difference
test,
the Wilcoxon signed ranks test, and a permutation test. We describe
some
advantages, disadvantages and properties of the different comparison
methods.
Test results provide no evidence for significant differences in the
phylogenetic
signal among the three nuclear data sets, with the exception of the
placement
of a single taxon. The chloroplast DNA restriction site data, on the
other
hand, support a significantly different tree, and the differences
probably
reflect a separate evolutionary history of the chloroplast genome.