The results from the experiments outlined in this proposal will provide for the first-time information about the inheritance of 2,4-D and dicamba resistance in Palmer amaranth. An important aspect in predicting the evolutionary track of an herbicide-resistance trait is to understand the genetic basis of herbicide resistance. Evolution of herbicide resistance in weeds is a consequence of the intense selection pressure applied primarily by using herbicides as the main weed control strategy. Despite the inevitable selection for herbicide-resistant weed biotypes, we must constantly investigate possible strategies to delay the evolution of resistance that results from using herbicides.