INHERITANCE OF DICAMBA RESISTANCE IN WILD MUSTARD (BRASSICA KABER)

The inheritance of resistance to dicamba in wild mustard was determine d by making reciprocal crosses between a resistant (R) population deri ved from a field treated repeatedly with auxin-type herbicides, and a known susceptible (S) population, The resulting F-1 hybrids were selfe d to produce F-2 populations and backcrossed to the S parent. At the t hree- to four-leaf stage, parental, F-1, F-2, and backcross population s were screened for resistance to dicamba at three dosages (50, 200, a nd 400 g al ha(-1)). F-1 progeny survived all dosages and exhibited le vels of injury similar to the R parental population, F-2 populations s egregated in a 3:1 ratio of R to S phenotypes, Progeny of backcrosses segregated in a 1:1 (R:S) ratio, Responses of the F-1, F-2, and backcr oss populations to treatment with dicamba indicate that resistance is determined by a single, completely dominant nuclear allele.