Molecular basis for resistance to fenoxaprop-p-ethyl in American sloughgrass (Beckmannia syzigachne Steud.)

American sloughgrass is a widespread and competitive annual grass weed of wheat in Yangtze River delta of China. Whole-plant dose-response experiments were conducted with fenoxaprop-p-ethyl to confirm and characterize resistant and susceptible American sloughgrass populations. The resistant American sloughgrass population Dylj was 21.73-fold resistant to fenoxaprop-p-ethyl relative to the susceptible population Dyyh. PCR analysis was conducted to elucidate the basis of resistance to the herbicide. Molecular analysis of resistance confirmed that the Ile(1781) to Leu mutation in the resistant population conferred resistance to fenoxaprop-p-ethyl. This is the first report of a target site mutation that corresponded to resistance to fenoxaprop-p-ethyl in American sloughgrass. (C) 2013 Elsevier Inc. All rights reserved.