CAYOUETTE1, JACQUES*, PAUL M. PETERSON2, BRUCE COULMAN3, AND YASAS FERDINANDEZ3. 1Eastern Cereal and Oilseed Research Centre, Agriculture and Agrifood Canada, Ottawa, ON, K1A 0C6, Canada; 2Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0166; 3Saskatoon Research Centre, Agriculture and Agrifood Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada. - Morphological, cytological, and molecular characterization of the Bromus ciliatus complex (Poaceae: Bromeae).
The Bromus ciliatus L. complex consists of diploids and
tetraploids from throughout North America with considerable
morphological variation. To determine levels of variability we have
sampled 32 populations of this complex from eastern and western
Canada, California, and Arizona. Important morphological characters
that vary within this complex are pubescence (presence/absence and
density) on the basal sheaths, nodes, and lemmas, and glume length.
Morphological and cytological data from these populations and from
herbarium specimens suggest that at least three groups are involved.
One group (B. ciliatus sensu stricto) from throughout the range
of the complex seems to consist of diploid individuals. Another group
(B. richardsonii Link) consists of tetraploid individuals
occurring in the Rocky Mountains from Alaska to southern California
with isolated populations found in the Cypress Hills of southern
Saskatchewan and Alberta. A peculiar combination of characters seems
to distinguish a third group that is sympatric with the other two
groups in Arizona and New Mexico. A detailed molecular
characterization using RAPD markers to determine genomic relationships
and genetic diversity within this complex has yielded valuable
information. A discriminate analysis of all available characters will
Key words: Bromeae, Bromus, cytology, molecular genetics, morphology, Poaceae