Current Status of Herbicide Resistance of Wild Oats (Avena spp) in Wheat Fields in Mardin and Şanlıufa Provinces of Türkiye

Abstract

Wheat is a strategic crop with its role in human nutrition. In Türkiye, it has importance in agriculture and economy as well as being a staple crop. Mardin and Şanlıurfa provinces of Türkiye approximately produces 1.6 million tons of wheat on 600 thousand ha fields. One of the important factors limiting wheat production is weeds. Weeds compete with the wheat plant and cause significant yield and quality loss. Wild oat (Avena spp.) species are an important problem in wheat fields in both provinces. Herbicide applications are widely used to control wild oats due to their ease of use, short duration of action and low cost. Wheat fields were surveyed to supply data for strategies to be followed via determining the current situation of herbicide resistance in these provinces where herbicide resistant wild oats had been reported. Out of 95 fields visited, 65 fields had significant wild oat populations of which 61 A. sterilis and four A. fatua. Then these populations were tested to find out herbicide resistance levels against clodinafop-propargyl (ACCase inhibitor) and formulated mix of mesosulfuron-methyl and iodosulfuron-methyl sodium (ALS inhibitors). Only two populations, one low level and the other medium level were found to be resistant to the formulated mix of mesosulfuron and iodosulfuron while 11 populations were resistant to clodinafop, one high level, three medium level and the remaining low level. It was assumed that longer use history and wider use of clodinafop as well as herbicides used in winter rotational crops might cause more clodinafop resistant populations. It was concluded that a strategy to prevent or delay herbicide resistance in these provinces should be prepared because herbicide resistance has continued evolving.