Monitoring the spread of ACCase inhibitor resistance among wild oat (Avena fatua) patches using AFLP analysis

The relative genetic similarity of 37 wild oat samples was determined using amplified fragment length polymorphism (AFLP) analysis. These data were compared with the herbicide-resistance characteristics of each sample to determine the importance of mutation and gene flow in the spread of Acetyl-CoA Carboxylase (ACCase) inhibitor resistance. There was a strong association between the genotypic clustering of samples, their herbicide-resistance characteristics, and their field of origin. Up to eight separate patches in a field were genetically similar, confirming that gene flow by seed movement is important in the distribution of resistant (R) wild oat seed. A greater emphasis on field scouting and treatment of wild oat patches could reduce the spread of resistance within fields. Samples collected from different fields were also found to be genetically similar, indicating that R wild oat was spread between fields. Improved sanitation of tillage and harvesting equipment and the use of certified seed could limit such seed movement.