Fenoxaprop resistance in sterile wild oat (Avena sterilis) in wheat fields in Turkey

Wheat has been traditionally an important crop in Turkey. Wild oat species (Avena spp.) have high occurrence and intensity in most regions of Turkey. Chemical control of wild oat has been used since the 1970s. Surviving sterile wild oat (Avena sterilis) plants after an ACCase herbicide application were first detected in the late 1990s. Seven (AKR1; AKR2; DZC; GKY1; GKY3; KMP; KMT) of 20 populations examined, were regarded as resistant to fenoxaprop with a range of R/S ratios of 2.41 and >8.0. All these populations were also cross resistant to clodinafop. AKR2 population showed cross-resistance to all ACCase herbicides examined. KMT population was resistant to all APPs but not CHDs, excluding partial resistance to tralkoxydim. GKY1 population exhibited resistant only to fenoxaprop but not resistant to other APP or CHD herbicides. No multiple resistance was detected to imazamethabenz, iodosulfuron+mesosulfuron or trifluralin except GKY1, which had multiple resistance to flamprop.