Description:
Derived from A. hybridus seed collected from a soybean field in Edgar County, Illinois. The original population was evaluated for ALS-inhibitor resistance at the seedling stage with an imazethapyr (BASF Corporation) application of 900 g/ha (>10 times the normal field rate). Resistant individuals were selfed to obtain several S1 populations. A subset of the progeny from each S1 population were screened for herbicide resistance (as indicated above), and a uniformly resistant population (S1) was selected for this study. The control A. hybridus population used was obtained from selfing herbicide-susceptible parents grown from seed collected in an Illinois field.