hamid reza sasanfar

The development of herbicide-resistant weed species is a threat to the agricultural industry in Iran and the world. The first step in managing this issue is the identification of herbicide-resistant populations. In this study, 124 and 45 grass weed accessions, including winter wild oat, annual ryegrass, and littleseed canarygrass, were collected from wheat and canola fields, respectively, in different provinces of Iran. The accessions were screened using commonly used herbicides at the three- to four-leaf stage. The weed accessions collected from wheat fields were exposed to the recommended field dose of clodinafop-propargyl, pinoxaden, mesosulfuron-methyl+iodosulfuron-methyl-Na, and mesosulfuron-methyl+iodosulfuron-methyl-Na+diflufenican. Similarly, the canola grass weeds were treated with haloxyfop-R-methyl, sethoxydim, cycloxydim, and clethodim. The experiment was carried out based on a completely randomized design with four replications under controlled greenhouse conditions. Four weeks after spraying, the fresh weight of the populations was measured. The results showed that 52, 9, 19, and 17% of grass weeds in wheat fields were resistant to clodinafop-propargyl, pinoxaden, mesosulfuron-methyl+iodosulfuron-methyl-Na, and mesosulfuron-methyl+iodosulfuron-methyl-Na+diflufenican, respectively. Morover, 47, 47, and 22% of the canola grass weeds showed resistance to haloxyfop-R-methyl, sethoxydim, and clethodim, respectively; while they were susceptible to cycloxydim. Cross-resistance to selective herbicides in canola was observed in 36% of the tested grass weed species. Additionally, multiple resistance to both ACCase and ALS inhibitors in wheat fields was identified in 13% of winter wild oat and 82% of annual ryegrass populations, respectively. It is recommended to avoid the use of herbicides with the same mechanism of action for controlling grass weeds in areas where the wheat and canola rotation system is prevalent

To evaluate the application of the image processing method (RGB and Lab methods) compared to the visual evaluation method for determining the seed viability or stainability of wheat (Triticum aestivum) and hairy vetch (Vicia villosa) using tetrazolium test, a factorial experiment based on a completely randomized design with three replications was conducted in the laboratory of Department of Mechanical and Biosystems Engineering of the Faculty of Agriculture, Tarbiat Modares University in 2019. The experimental factors included methods for determining seed stainability (visual assessment, RGB, and Lab methods), two plant species (wheat and winter vetch), physical stratification (cross cutting, longitudinal cutting, sanding, needling, and control), and duration of exposure to tetrazolium (10 and 24 hours). The results showed that the stainability of seeds exposed to tetrazolium for 24 hours was higher than those exposed for 10 hours. The highest stainability of seeds was observed in the longitudinal cutting treatment for both wheat and hairy vetch species in the all three determining seed stainability methods. The RGB and Lab methods showed the highest stainability percentage for wheat and hairy vetch seeds, respectively, where the seeds were cut longitudinally. Therefore, the RGB and Lab image processing technique can be used as a fast, precise, and new method for determining the seed viability of crops and weeds through the tetrazolium test.

Forty-six suspected herbicide-resistant winter wild oat populations collected from wheat fields of Khuzestan province were screened in a whole plant bioassay using the recommended field dose of mesosulfuron methyl+idosulfuron methyl (Atlantis %1.2 OD) and mesosulfuron methyl+idosulfuron methyl+diflofenican (Othello %6 OD). The resistance index of two populations, with the highest percentage of herbicide resistance recorded at the screening tests, to the mentioned herbicides was tested in a dose-response experiment. Thirteen and six populations showed resistance to Atlantis based on Adkins and Moss methods, respectively. Also, 18 and three populations were classified as Othello resistant populations based on Adkins and Moss methods, respectively. This is the first report of resistance to Othello in winter wild oat populations collected from Khuzestan province. A distribution map of winter wild oat populations resistant and susceptible to herbicides was prepared based on the results of the screening test. Herbicide resistance index to Atlantis in two dose-response experiments for the studied populations was ranged between 8.9 and 15.1. Herbicide resistance index to Othello was ranged between 3.3 and 15.0. Due to an increase in herbicide-resistant populations to ALS inhibitors in Khuzestan province, herbicide-resistant winter wild oat management programs should be pursued more seriously.

Winter wild oat is one of the most problematic weeds in many crops, especially wheat; however, the widespread and continuous application of herbicides has led to its resistance to herbicides in different parts of the country. This study was conducted to compare the proteome between susceptible and resistant biotypes of wild oats to ACCase and ALS inhibitors using Tandem Mass Spectrometry (MS/MS) and the iTRAQ techniques. The results of this study in terms of comparing the differential proteins identified 138 Proteins with Differential Expression (DEPs) in resistant biotypes and 93 DEPs in susceptible biotypes. Also, based on the results of Gene Ontology analysis (GO), proteins with differential expression under herbicide treatments in susceptible and resistant biotypes were classified in three main categories including molecular functions (MF), biological processes (BP) and cellular components (CC). Analysis of differential protein enrichment pathways using KEGG showed that the richest pathways included metabolic pathways, carbohydrate metabolism, and secondary metabolites. Among the proteins responsible for the defense response, superoxide dismutase (Q0DRV6) and among the proteins responsible for herbicide detoxification, cytochrome P450 (Q6YSB4) had up-regulation in resistant biotype. The major proteins involved in photosynthesis including petA, psaA, large RuBisCo subunit (rbcL), chlorophyll a and b and cytochrome b6 (petB) in the resistant biotype had down-regulated, while in the susceptible biotype, psaB, psaA, psbD, psbB and petB proteins had up-regulated. In addition, a salinity-related protein, such as Q6K4S7 protein, was up-regulated in resistant biotypes, and it appears that these proteins may play a role in herbicide resistance.

This study was conducted to investigate the resistance of problematic grass weeds including winter wild oat (Avena ludoviciana), annual ryegrass (Lolium rigidum) and canary grass (Phalari minor) to commonly used herbicides in canola fields at Iranian Research Institute of Plant Protection in 2019 in a completely randomized design with four repetitions. For this purpose, 29 accessions of wild oat, 15 accessions of ryegrass and 8 accessions of canary grass were collected from canola fields located in Fars, Mazandaran, and Ardabil provinces. Seedlings of the weed species, after growing under controlled conditions, were exposed to the recommended doses of haloxyfop-R-methyl, sethoxydim, cycloxydim and clethodim herbicides at 2-3 leaf stage. Fresh weight, dry weight, and survival percentage of plants were measured four weeks after treatment. Based on fresh weight reduction, 86.7%, 66.7% and 60% of annual ryegrass accessions were resistant to haloxyfop-R-methyl, sethoxydim and cycloxydim, respectively. Also, 25% of canary grass accessions were resistant to haloxyfop-R-methyl, based on fresh weight loss, while 12.5% of accessions were classified as suspected resistant to sethoxydim. Of 29 wild oat accessions, 31% were resistant to halloxypop-R-methyl based on fresh weight reduction. Only one wild oat accession was resistant to clethodim. The occurrence of definite resistance in other wild oat accessions to the three dim herbicides was not confirmed. Generally, resistance of narrow-leaved weeds to some commonly used graminicides in broadleaf crops such as canola has been developed. Therefore, it is recommended to restrict application of herbicides with the same mechanism of action, while following crop rotation.

The present study was conducted to investigate the effect of different water hardness levels on the efficacy of clodinafop-propargyl and mesosulfuron+iodosulfuron+mefenpyr-diethyl with and without adjuvants in control of winter wild oat (Avena ludoviciana). The experiment was conducted as a randomized complete block design in factorial arrangement with three replications at the research greenhouse of Iranian Research Institute of Plant Protection during 2017-2019. The experiment factors included herbicides doses at four levels of 25, 50, 75% and 100% of the recommended field rate of each herbicide (the recommended dose for Topik and Atlantis were 64 and 18 g a.i ha-1 , respectively), concentrations of hardness at five levels (0, 250, 500, 750 and 1000 ppm of Calcium bicarbonate) and different levels of ammonium sulfate and urea ammonium nitrate adjuvants at three levels (0, 1 and 2% v/v). The results indicated that the water hardness higher than 500 ppm led to a reduction in the efficacy of clodinafop-propargyl in control of winter wild oat. However, the efficacy of mesosulfuron+iodosulfuron+mefenpyr-diethyl was not influenced by any level of water hardness. According to the results of this experiment, the use of ammonium sulfate 2% or ammonium urea nitrate 1 to 2% reduced the negative effects of hard water containing calcium carbonate with a concentration of more than 500 ppm on the effectiveness of the herbicide clodinafop-propargyl, and reduced the recommended dose of this herbicide by 25 to 50%. Furthermore, the use of ammonium sulfate 2% or urea ammonium nitrate 1% increased the efficacy of mesosulfuron+iodosulfuron+mefenpyr-diethyl.

The spread of weed resistance to herbicides is expanding in Iran; therefore, monitoring of resistance to the most commonly used herbicides and evaluation of cross-resistance to the herbicides were carried out on 38 canarygrass accessions collected from wheat fields in five provinces (Golestan, Fars, Khuzestan, Ardabil and Tehran provinces) of Iran. The whole plant screening test was conducted with four replications in the greenhouse of Iranian Research Institute of Plant Protection in 2019. Plants at the two- to -three leaves stage were exposed to the recommended field dose of herbicides. Four weeks after spraying, the percentage of fresh and dry weights and plants survival were measured. Of the 38 accessions, 13 (34%), eight (21%), two (5%) and one (about 2.5%) accessions were classified to being high resistant and suspected resistant to mesosulfuron+iodosulfuron+mefenpyr-diethyl (Atlantis), clodinafop-propargyl (Topik), pinoxaden (Axial), and mesosulfuron+iodosulfuron+difloficane+mefenpyr- diethyl (Othello), respectively. Overall, mesosulfuron+iodosulfuron+diflufenican+mefenpyr- diethyl and pinoxaden showed higher efficiency on the accessions than the other two herbicides. Cross-resistance to clodinafop-propargyl and pinoxaden herbicides was observed in two accessions (GM1 from Golestan, PA1 from Ardabil). One accession (AL1) from Golestan province showed resistance to mesosulfuron+iodosulfuron+mefenpyr-diethyl and mesosulfuron+iodosulfuron+diflufenican+mefenpyr- diethyl. Resistance to ACCase inhibitors in the accessions collected from Khuzestan province and the cross-resistance in the accessions collected from Golestan and Ardabil provinces showed the rapid development of herbicide resistance problem in Iran, especially in the mentioned provinces. Therefore, it is necessary to pay more attention to the prevention, delay and management of canarygrass herbicide-resistant accessions.

In order to survey the resistance of wild oat populations to clodinafop propargyl herbicide, an experimental study was conducted at the Department of Weed Science, Plant Pest and Disease Research Institute greenhouse in 2008. Treatments included 12 wild oat populations suspected of being resistant to clodinafop propargyl and a susceptible biotype collected from Fars Province. A dose-response study was conducted for 13 wild oat populations. In this study, wild oat populations were sprayed during the 2–4 leaves stage using eight doses of clodinafop propargyl including 0 to 16 times the recommended dose (64 g ai ha-1). Biomass and surviving plant measurements were performed four weeks after herbicide application. Results of this study indicated that all suspected populations were resistant to clodinafop propargyl herbicide. The comparison of resistance index on the basis of biomass and surviving plants showed that the W/F-M2/85 population from Marvdasht had the highest level of resistance. This population could preserve over 50% more of both biomass and surviving plant relative to the control at 16 times (1024 g ai ha-1) the recommended dose.