Investigating the resistance of wild oat (Avena ludoviciana Durieu.) to fenoxaprop-p-ethyl by whole plant bioassay and seed bioassay.

Greenhouse and laboratory experiments were performed to evaluate the resistant of wild oat Avena luduviciana Durieu. populations to fenoxaprop-p-ethyl. Populations of A. ludoviciana were collected from different locations in Iran, showed indications of resistance to this herbicide. Whole plant assay experiments included screening tests and dose response experiments whereas; seed bioassay experiment consisted of ID50 determination and dose response experiments. Whole plant assay experiments were conducted as a randomized complete block design in four replications. The treatments were wild oat populations included FR1, FR2, FR3, FR4 (collected from Fars province), MR1, MR2, MR3 (collected from Markazi province), KS, KR1, KR2, KR3 (collected from Khuzestan province) and S (collected from location which had never been treated previously with any graminicide). Seed bioassay experiments were conducted using a randomized design with 4 replications. On the whole plant basis, resistance was found in, KR1, KR2, KR3 and FR4 and based on a seed bioassay, these populations were also resistant to fenoxaprop-p-ethyl. Resistance ratios (R/S) of resistant populations were different. Present findings also revealed that the seed bioassay could be used as a simple, comparatively rapid, inexpensive and accurate method for identifying wild oat populations resistant to Acetyl CoA carboxylase (ACCase) inhibitors.