| dc.description.abstract | The genus Brassica comprises economically important oilseed and vegetable crops. Their
susceptibility to fungal diseases such as blackleg causes yield loss. In this study, thirty accessions
from USDA germplasm collection representing two diploid Brassica species (Brassica rapa and
Brassica oleracea var. virids) and fifteen tetraploid cultivars (Brassica napus) from the national winter
canola variety trials (NWCVT) were evaluated using 13 sets of random amplified polymorphic DNA
(RAPD) associated with blackleg resistance in Brassica nigra. 126 highly polymorphic bands with an
average of 10 per primer were detected. A UPGMA dendrogram showed B. rapa as highly diverse and
was supported from three different basal branches, while B. napus accessions were generally
monophyletic. Similarly, all of B. oleraceae accessions were supported from the same basal node.
Generally, the three species were reciprocally paraphyletic, suggesting that the RAPD markers showed
both functional relationships as well as homology, possibly due to selection at the RAPD loci
associated with blackleg resistance. Consequently, two potentially susceptible B. napus accessions
were identified. The high polymorphic information content (PIC) and number of phylogenetically
informative bands established RAPD as a useful tool for phylogenetic reconstruction, quantification of
genetic diversity for conservation, cultivar classification and molecular breeding in Brassica. | en |
