Content area
Abstract
Genetic diversity in white pine blister rust has been previously described to reside mostly within cankers and within white pine natural stands or plantations for the dicaryotic aecidial stage, with very little genetic differentiation between populations observed in Quebec and British Columbia. The aim of the current study was to extend such comparisons to white pine blister rust populations from five Eastern and one Western Canadian provinces. The analysis of gene diversity using Lynch and Milligan's corrections for the dominance of RAPD markers, indicated a low level (5.8%) of genetic differentiation among populations including populations from Newfoundland and Ontario, which are separated by 3000 Km. An analysis of molecular variance revealed that most (94%, p $<$ 0.001) of the genetic variability was present within populations (mostly plantations) with minor levels of genetic differentiation among regions (0.02%, p = 0.475) or among populations (6%, p $<$ 0.001). By contrast, a significant (28%, p $<$ 0.001) level of genetic differentiation was found between one population from British Columbia (west) and three Quebec populations (east). These results suggest that there is probably an important gene flow between homogenized populations of C. ribicola populations of C. ribicola in eastern Canada, but that there is a barrier to gene flow between eastern and western populations.