Document Type : Research Paper
Authors
1
Agronomy and Plant breeding Dept., College of Agriculture and Natural Resources, University of Tehran
2
Agronomy and Plant Breeding Dept., Faculty of Agriculture, University of Tehran, Karaj, Iran.
3
Assistant Professor, Iranian Research Iinstitute of Plant Protection
4
Agronomy and Plant Breeding, Faculty of Agriculture, University of Tehran
10.22034/ijws.2024.133856
Abstract
Due to the spread of weed resistance to herbicides in Iran, it is necessary to monitor this phenomenon and evaluate effective factors in the occurrence of weed resistance to herbicides. Therefore, resistance to the common herbicide clodinafop-propargyl in 133 wild oat populations collected from wheat fields in Ardabil (13 populations), Kermanshah (10 populations), Khuzestan (43 populations), Fars (29 populations), and Golestan (38 populations), and the evaluation of factors affecting herbicide resistance risk in these cropping systems were investigated. The screening test was conducted as a whole-plant bioassay using a completely randomized design with four repetitions in greenhouses at the Iranian Research Institute of Plant Protection in 2019. The accessions were exposed to the recommended field dose (80 g ha-1) of clodinafop-propargyl (Topik, EC 8%) at the two- to three-leaf stages. Four weeks after spraying, the percentage reduction in fresh weight of the plants was calculated compared to the untreated control. The results showed that out of the 133 wild oat populations studied, 87.2% (116 populations) were classified as highly resistant (RRR), 4.5% (six populations) as resistant (RR), 1.5% (two populations) as suspected of resistance (R?), and 6.8% (nine populations) as susceptible (S) to clodinafop-propargyl. In the 5-year study period, in wheat fields where no crop rotation was applied and only clodinafop-propargyl was used, there was a 100% incidence of herbicide resistance in the populations (94% high resistance (RRR) and 6% resistance (RR)). Given the direct relationship between the occurrence of resistance in wild oat populations and the prevailing management methods in wheat fields, as well as the risk of further spread, it is necessary to pay serious attention to changing cropping patterns and management systems, including prevention and compliance with crop and chemical rotation.
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