Using the dCAPS Method to Detect the Resistance of Wild Oat (Avena ludoviciana Durieu.) to Clodinafop-propargyl in Comparison with Current Methods

In order to evaluate the resistance of 17 biotypes of wild oat to clodinafop-propargyl herbicides, four methods including: whole plant screening, whole plant bioassay, seedling bioassay and molecular method were used. There was similarity between the results of whole plant screening, whole plant bioassay, seedling bioassay, but resistance ratio (R/S) of seedling bioassay was lower than whole plant bioassay and it seems that seedling bioassay is a reliable method for identifying populations of grass species resistant to ACCase inhibiting herbicides. According to the molecular methods, an isoleucine-1781-leucine [Leu] mutation in plastidic ACCase enzyme of 8 biotypes (44% of biotypes) has been identified as the known mutation endowing clodinafop-propargyl resistance and isoleucine-2041-asparagine mutation has not been identified as a mutation endowing resistance in none of biotype. The resistance mechanism of the rest of biotypes that were resistance according to the non-molecular method, but did not identify resistant by molecular method, can be explained by mutation in another location or metabolism-based mechanism.