Weedy wheat fields can produce 40 to 50 percent less grain than uninfested fields. The grass weeds can become almost completely resistant to diclofop in as little as three years. Understanding the biological mechanism of resistance would help scientists develop better controls for this and other grass weeds. The ARS scientists have already showed that ryegrass' chemical resistance is controlled by only one or two genes. Studying how resistance developed has been difficult because researchers have lacked populations of resistant and susceptible plants that were otherwise identical.
Researchers can now make comparisons using the new lines.
ARS scientists developed them from selections from Gulf and Marshall ryegrass varieties.