Resistance of Winter Wild oat (Avena ludoviciana Durieu.) to Aryloxyphenoxy Propionate Herbicides in Wheat Fields of Khuzestan Province: First Screening Test

Abstract

To study resistance of winter wild oat (Avena ludoviciana) to clodinafop propargyl<br><br>(Topik), diclofop methyl (Illoxan), and fenoxaprop p ethyl (Puma super) herbicides<br><br>in wheat fields of Khuzestan province, seedlings of 46 wild oat population were<br><br>collected from farmers' fields at seven sites of the province including Ahvaz,<br><br>Andimeshk, Shush, Shushtar, Ramhormoz, Susangerd (Dashte Azadegan), and<br><br>Dezful. The seed samples were screened in the greenhouse College of Agriculture,<br><br>Ferdowsi University of Mashhad, in 2005. Clodinafop propargyl, diclofop methyl,<br><br>and fenoxaprop p ethyl, were applied at recommended rates of 64, 900, and 75 g ai<br><br>ha-1, respectively. Each experiment was laid out in a completely randomized design<br><br>with 3 replications. Visual phytotoxicity rating, the percentage of survived plants,<br><br>and relative dry weight (percentage of control) were used to evaluate seed<br><br>population response to herbicide treatment. Results showed that moderate but<br><br>statistically significant variation in winter wild oat resistance existed amongpopulations from different sites and among populations in wheat field of the same.<br><br>Seed populations collected from Shushtar and Ramhormoz showed higher<br><br>resistance to all three herbicides. It could be concluded that some winter wild oat<br><br>seed populations collected from Khuzestan wheat fields are suspected to herbicide<br><br>resistance.