| high genetic diversity in french invasive populations of common ragweed, ambrosia artemisiifolia, as a result of multiple sources of introduction. | ambrosia artemisiifolia is an aggressive north american annual weed, found particularly in sunflower and corn fields. besides its economic impact on crop yield, it represents a major health problem because of its strongly allergenic pollen. ragweed was imported inadvertently to europe in the 18th century and has become invasive in several countries, notably in the rhône valley of france. it has recently expanded in both the provence-alpes-côte-d'azur and bourgogne regions. as first steps towards ... | 2005 | 16313592 |