The introduction of chemical means of eradicating pest species intensified agricultural production, but at the cost of rapid evolution of resistant organisms. Our observation of the evolution of novel tolerance to the herbicide RoundUp. In the common morning glory, Ipomoea purpurea, provides an excellent example of human-mediated evolution. We have evidence from a preliminary greenhouse study that there is genetic variation among maternal lines of Ipomoea purpurea for tolerance to RoundUp. We will further investigate the evolution of this trait by studying the genetic control of herbicide tolerance and the potential constraints on its evolution. The experiments will examine how tolerance is inherited by performing greenhouse crosses and subsequent progeny analyses. The potential for constraints on the evolution of tolerance will be investigated by comparing relative fitness of herbicide tolerant and susceptible individuals in the absence of herbicide in the field. The broader impacts of this study are manifest to U.S. agriculture. Since use of RoundUp is increasing markedly, it is critical that evolutionary analyses of its use be completed. An understanding of the genetic basis and fitness costs of tolerance to this herbicide will be of broad importance.
