A molecular genetic assessment of herbicide-resistant Sinapis arvensis

The acquisition of resistance to both the auxinic herbicide dicamba and the sulfonylurea herbicide chlorsulfuron has been recorded in Canadian populat ions of the weed species Sinapis arvensis L, (charlock, wild mustard) To st udy the effect of this selection for herbicide resistance on levels of gene tic variation, polymerase chain reaction-based DNA fingerprinting technique s were used to characterize two herbicide-resistant and one susceptible pop ulation of S. arvensis. Analysis of the resultant DNA marker profiles revea led extensive polymorphism between individuals. However, segregation of the three biotypes was detectable despite high levels of intrabiotype polymorp hism. No reduction in the levels of heterozygosity within the resistant pop ulations were found compared with the susceptible population.