Resistance of various biotypes of Canary grass (phalaris. Spp) to acetyl-CoA carboxylase-inhibiting herbicides

Little seed canary grass (Phalaris minor L.) is a major weed in wheat fields in some parts of Iran. To evaluate the efficacy of molecular and greenhouse methods in detecting the resistance of 49 biotypes of canary grass(Phalaris. Spp) to acetyl-CoA carboxylase-inhibiting herbicides, two methods including whole plant screening and PCR-based molecular methods were applied. Results showed that there were resistant biotypes (ile-1781-Leu) among the studied weed populationand the similarity between greenhouse and molecular methods was 67%. According to the molecular method, an isoleucine (ile) 1781 to leucine (leu) mutation in plastidicACCase enzyme of 30 biotypes (67% of biotypes) was identifiedas a mutation endowing to the clodinafop-propargyl resistance. The partial differences of about 33% between greenhouse and molecular methods can be explained by mutation in another location or through another metabolism –based mechanism.