Weed Survey of Acetolactate Inhibitors and Acetyl Coenzyme A Carboxylase Suspected Resistant Weeds of Wheat (Triticum aestivum) Fields in Khuzestan and Kermanshah Provinces

To survey herbicide resistant weeds in wheat fields an experiment was conducted on suspected biotypes collected from Khuzestan and Kermanshah provinces of Iran during 2010. Seeds of 30 and 50 suspected resistant wild oats biotypes collected from wheat fields of Khuzestan and Kermanshahprovinces، respectively. In this study، Seeds of suspected resistance to wild oat (Avena ludoviciana) were gathered and tested in a randomized complete blocks design. Management information of fields were collected and analyzed. According to the results of Khuzestan، 66% of biotypes were resistant to Clodinafop- propargyl (Topik)، 14% resistant to Iodosulfuron-methyl-sodium + Mefenpyr-diethyl (Chevalier) and about %11 resistant to both herbicides. Furthermore، 66% of fields used herbicides with different sites of action، but in 80% of the fields، crop rotation، the most important recommendations for reducing weed population resistant to the herbicide، was not observed. Kermanshah province had a better crop rotation in comparison with Khuzestan، and 75% of the crop rotation in this province was acceptable. On the other hand، herbicide rotation was not acceptable in this province. Thus، Clodinafop- propargyl was the main graminicide that was used in the wheat fields (77% of fields) and Tribenuron-methyl was used in 45% of the field. Generally، it seems that، in spite of the good recommendations that have provided for management of herbicide resistance in wheat fields، farmers do not fallow the recommendations. If this situation continues، herbicide resistance in several grass weed species will threaten the agronomic and economic sustainability of wheat production in some provinces ofIran.