نوع مقاله : پژوهشی
نویسندگان
1 گروه مهندسی تولید و ژنتیک گیاهی، دانشکده علوم و مهندسی کشاورزی، دانشگاه رازی
2 گروه مهندسی تولید و ژنتیک گیاهی، دانشکده علوم و مهندسی کشاورزی، دانشگاه رازی'
3 دانشکده کشاورزی، دانشگاه ایوانینا، یونان
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Catchweed bedstraw (Galium aparine L.) and wild mustard (Sinapis arvensis L.) are among the most problematic broadleaf weeds of winter cereals in western Iran. Reports indicate these weeds have developed resistance to the commonly used herbicides 2,4-D and 2,4-D + MCPA in western Kermanshah province. The primary resistance mechanism to 2,4-D is reduced translocation from treated leaves to other plant parts. However, other off-target resistance mechanisms have not been sufficiently investigated. Therefore, the main goal of this research, besides confirming resistance to these herbicides, is to reveal increased 2,4-D metabolism in resistant populations of weeds like Catchweed bedstraw and wild mustard to synthetic auxins.
Materials and methods: Seeds of Catchweed bedstraw and wild mustard weeds were collected from 10 diverse fields in Kermanshah province in spring and summer 2017, including Sarpol-e-Zahab, Gilan-e-Gharb, Islamabad, Kozran, Ravansar, and Mahidasht. The populations had received two-way herbicides (2,4-D and 2,4-D + MCPA) at least three times in the past five years. A sample of the susceptible population was also collected from a field with no history of herbicide use. The experiments were conducted in the research greenhouse of Razi University. In the screening experiment, the suspected populations were sprayed with the recommended dose of two-way herbicide, and their resistance was evaluated based on biomass estimation on a scale of 0 to 10. The dose-response experiment was conducted with doses of 0 to 17280 g active ingredient per hectare with three replications. The leaf 2,4-D metabolism test was also performed at several time points after treatment with doses of 0, 600, and 2400 g of active ingredient per hectare. High-performance liquid chromatography (HPLC) was used to investigate the metabolism of 2,4-D.
Results: Among 23 Catchweed bedstraw biotypes and 15 wild mustard biotypes, two biotypes of each species showed resistance to herbicide application by maintaining 50% survival and seed production. The dose-response experiment showed that the effective dose for 50% dry weight reduction (X50) in resistant Catchweed bedstraw biotypes was 2028 and 973 g ha-1 under 2,4-D and 2,4-D + MCPA treatments, respectively, which was significantly higher than the doses of sensitive biotypes (291 and 326 g ha-1). For resistant wild mustard biotypes, X50 was 1411 and 864 g ha-1, respectively. The resistance index for resistant Catchweed bedstraw biotypes to 2,4-D herbicide was 6.95 and 2.98 for the 2,4-D + MCPA combination. The dry weight loss curves were sigmoid in shape, and the effect of 2,4-D + MCPA was stronger than 2,4-D alone. The metabolism of 2,4-D in the plant cell resulted in the hydroxy metabolites 2,3-D and 2,5-D, which were significantly increased in the resistant biotypes of Catchweed bedstraw and wild mustard. These metabolites were detected at higher concentrations (up to 4320 g ha-1) in the resistant biotypes of wild mustard, while they were observed at lower doses (405 g ha-1) in the susceptible biotypes. High resistance and resistance indices greater than six indicate a decrease in the efficacy of 2,4-D in these areas, and continuous use of this herbicide may limit effective weed control.
Conclusion: The findings indicate the existence of significant resistance to the herbicide 2,4-D in the biotypes of Catchweed bedstraw and wild mustard weeds, which has dramatically reduced the effectiveness of this herbicide. The use of the combination of 2,4-D + MCPA can slow down the resistance process, but the relative resistance is still a challenge. The metabolism of 2,4-D to hydroxy metabolites in resistant biotypes indicates a detoxification and resistance mechanism. Therefore, the combination of management and intelligent planning is essential for the control of resistant weeds.
کلیدواژه‌ها [English]
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