Evolution of herbicide resistance in Senecio vulgaris: variation in susceptibility to simazine between and within populations.
Intraspecific variation in susceptibility to simazine was examined in 46 different populations of Senecio vulgaris collected from various fruit growing areas in England. Significant differences were found between populations indicating a genetic basis for simazine susceptibility. A positive, linear relationship existed between % survival of a population and the number of consecutive years of simazine application, suggesting that selection had occurred. The genetic and environmental components of variance were examined in a single population from an apple orchard in Suffolk. Broad sense heritability was found to be low. From summary.