Barrier to Gene Flow Between Eastern and Western Populations of Cronartium ribicola in North America

Hamelin, R. C., Hunt, R. S., Geils, B. W., Jensen, G. D., Jacobi, V., and Lecours, N. 2000. Barrier to gene flow between eastern and western populations of Cronartium ribicola in North America. Phytopathology 90:1073-1078. The population structure of Cronartium ribicola from eastern and western North America was studied to test the null hypothesis that populations are panmictic across the continent. Random amplified polymorphic DNA markers previously characterized in eastern populations were mostly fixed in western populations, yielding high levels of genetic differentiation between eastern and western populations ( φst = 0.55; θ = 0.36; P 1) between New Mexico and British Columbia populations, but were smaller than one migrant per generation between eastern and western populations. These results suggest the presence of a barrier to gene flow between C. ribicola populations from eastern and western North America.