نشریه دانش علفهای هرز
سال هفدهم شماره 2 (پاییز و زمستان 1400)

Due to the existence of environmental hazards and the herbicide resistance, it is necessary to investigate the integration of herbicides with other non-chemical methods such as stale seedbed (SSB) in weed control of the potato field. This experiment was conducted as a split-plot based on randomized complete block design by three replications in at the Research Farm of Agriculture and the Natural Resources University of Tehran in 2013 and 2014. The main plots were in three levels: 1- conventional seedbed preparation, 2- SSB + Paraquat, and 3- SSB + glyphosate. Sub-plots were four treatments included the application of rimsulfuron, metribuzin, pendimethalin, and rimsulfuron + nicosulfuron herbicides. The results of interaction showed that according to the total weed control, the best treatment was SSB + paraquat and application of metribuzin, reducing 95.4% of density and 83.3% dry weight of total weeds and it had a tuber yield of 31.8 T ha-1. Therefore, this treatment was the most cost-effective of weed control in potato, because, it showed a better control of weeds, and cause of less injury to potato, so it produced the higher yield.

Nicosulfuron belongs to the group of herbicides that has soil residue and its residue in the soil cause damage to sensitive crops in crop rotation.. In order to study the nicosulfuron herbicide persistence in the soil under biological and chemical degradation of nicosulfuron herbicide in soil, under controlled conditions, an experiment was carried out in a factorial randomized complete block design with three replications during 2015-2016. The first factor included conditions of sterile and non-sterile soil and fertilizer, the second factor included the application of organic and bio-fertilizers at four levels of cow manure, vermicompost, mycorrhiza (2 % w/w) and control treatment without fertilizer, the third factor also included incubating periods at eight levels 0, 4, 8, 16, 35, 50, 80, 100 days. The results showed that nicosulfuron degradation was chemical hydrolysis under sterile conditions, and was biodegradation and chemical hydrolysis under non sterile conditions. Nicosulfuron degradation rate was not significant difference in control treatment (without organic fertilizers application) under conditions of sterile, non-sterile fertilizer and soil, But increased with application of organic and bio-fertilizers and deacresed residue herbiced. The lowest residue rate was obtained from the application of cow manure under non-sterile (0.01 mg/kg/ day) and sterile 0.03 mg/kg/ day) conditions. The highest and the lowest degradation rate were obtained from the application of cow manure under non-sterile conditions and control treatment under sterile conditions. Also the lowest and the highest half-life was obtained by 15.33 and 38.5 day from the application of cow manure under non-sterile conditions respectively.

Field experiments were conducted to evaluate the efficacy of mesotrione+nicosulfuron and bentazon+MCPA, two new herbicides, in the control of broad-leaved weeds of corn in Alborz, Fars and Kermanshah provinces in 2018. The treatments consisted of mesotrione+nicosulfuron at three doses of 0.7, 1 and 1.3 L ha-1, bentazon+MCPA + weeding grass species at three doses of 1.5, 2 and 2.5 L ha-1, mesotrione+s-metolachlor+terbuthylazine at 4.5 L ha-1, nicosulfuron at 2 L ha-1, bromoxynil+MCPA at 1.5 L ha-1 + weeding grass species, rimsulfuron+nicosulfuron at 175 g ha-1, nicosulfuron at 2 L ha-1 + bromoxynil+MCPA at 0.5 L ha-1 and hand weeding control. Density and dry weight of weeds were evaluated 45 days after spraying. The results showed that mesotrione+s-metolachlor+terbuthylazine, nicosulfuron + bromoxynil+MCPA and bromoxynil+MCPA were the most effective herbicides (efficacy>85%) in control of broad-leaved weeds in all the studied provinces. Also, nicosulfuron and rimsulfuron+nicosulfuron controled broad-leaved weeds most effectively (by roughly 90% reduction in weeds dry weight) in Fars and Alborz provinces. The efficacy of 2.5 L ha-1 bentazon+MCPA in Fars and Alborz provinces were over than 85%, while this treatment led to 70% to 85% weeds control in Kermanshah province. The efficacy of none of the applied rates of mesotrione+nicosulfuron did not lead to a satisfactory control of broad-leaved weeds compared to the commonly used herbicide treatments. Moreover, bromoxynil+MCPA, nicosulfuron + bromoxynil+MCPA and manual weeding in Kermanshah and nicosulfuron in Fars resulted in the highest increase in corn grain yield by approximately 122% and 211% compared to the untreated control, respectively.

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.

In order to identify weed seeds by machine vision approach, two methods of artificial neural network (ANN) and canonical discriminant analysis (CDA) were applied. The seeds of Amaranthus retroflexus, Amaranthus blitoides, Chenopodium album, Alyssum hirsutum, and Sinapis arvensis were collected and the images of these seeds were recorded. The obtained images were processed and then characteristics related to the shape of each seed were extracted. The extracted data were in in the raw and standardized forms. In addition, main shape characteristics of the seeds were identified by stepwise regression. The results showed that the accuracy of the ANN constructed from the raw and the standard data were 84.30% and 83.39%, respectively. Identification accuracy of ANN was 84.30% and 83.39% for the raw and standard data extracted from stepwise regression. The results of CDA method showed that the identification accuracy of total raw and standard data were 84.9% and 84.7% respectively. Identification accuracy of this method was 82.6% for both raw and standard data extracted from stepwise regression. The highest identification accuracy in both methods (more than 95%) was belonged to A. retroflexus and A. hirsutum. In addition, the seed identification accuracy of C. album in both methods was higher than 87%. This suggests that the use of shape features in pattern recognition models had reliable potential in identifying the seeds of these weeds.

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.

Nicosulfuron belongs to the group of herbicides that has soil residue and its residue in the soil cause damage to sensitive crops in crop rotation.. In order to study the nicosulfuron herbicide persistence in the soil under biological and chemical degradation of nicosulfuron herbicide in soil, under controlled conditions, an experiment was carried out in a factorial randomized complete block design with three replications during 2015-2016. The first factor included conditions of sterile and non-sterile soil and fertilizer, the second factor included the application of organic and bio-fertilizers at four levels of cow manure, vermicompost, mycorrhiza (2 % w/w) and control treatment without fertilizer, the third factor also included incubating periods at eight levels 0, 4, 8, 16, 35, 50, 80, 100 days. The results showed that nicosulfuron degradation was chemical hydrolysis under sterile conditions, and was biodegradation and chemical hydrolysis under non sterile conditions. Nicosulfuron degradation rate was not significant difference in control treatment (without organic fertilizers application) under conditions of sterile, non-sterile fertilizer and soil, But increased with application of organic and bio-fertilizers and deacresed residue herbiced. The lowest residue rate was obtained from the application of cow manure under non-sterile (0.01 mg/kg/ day) and sterile 0.03 mg/kg/ day) conditions. The highest and the lowest degradation rate were obtained from the application of cow manure under non-sterile conditions and control treatment under sterile conditions. Also the lowest and the highest half-life was obtained by 15.33 and 38.5 day from the application of cow manure under non-sterile conditions respectively.

Swallow-wort (Cynanchum acutum) in recent years has aggressively infested sugarcane fields. Understanding seed germination behavior of this weed will save time to control it. In this investigation, germination of seeds was studied at five fruit cutting time with two weeks intervals at 14 to 70 days after fruiting (DAF) at five temperature levels 10, 20, 30, 40 and 50°C in Sugarcane research and training institute in 2017. The results showed that swallow-wort seeds were not able to germinate by the 14 DAF. From the 42 DAF thereafter, germination rate showed increasing trend and reached its highest value at 56 DAF, with 19.70 seeds per day. At the same time, the highest germination of swallow-wort seeds was 97% at temperature of approximately 30°C. By fitting the segmented model to the germination rate data, the minimum, optimum and maximum germination of mature seeds were 18.1, 32.6, and 57°C, respectively. Seeds from fruit at the 28 and 42 DAF required higher germination temperatures and showed decreasing trend with increasing the days from formation to complete ripened fruit. Based on the results of this study, it is necessary to plan for utilizing different methods of control such as removal the above ground organs as a management strategy and at maximum the second week after swallow-wort fruiting, to prevent production of seeds with ability of germination.

To evaluate the effects of plant density and reduced herbicide concentrations on the vertical distribution pattern of leaf area in red bean canopy profile in mixed bean cultivars, an experiment was conducted in a double-cropping plot design with 3 replications in the research farm of Tehran University in 2016. In this experiment, the reduced concentrations of herbicide at 5 levels (0%, 25%, 50%, 75% and 100% of recommended concentration with hand weeding treatment) were the main plots, bean plant density at three levels (40, 50 and 60 plants). M / s) were sub plots and pure cultivation system of standing cultivar and 50%-50% mixed cultivation in row of standing and creeping cultivars were sub-plot. The results showed that herbicide concentration increase resulted in the bean biomasses increase in different layers and the highest bean biomass (228 g/m2) was observed in the intercropping system and 60 plants/m2 density f in the hand weeding treatment in 30-40 cm layer and the lowest (123 g/m2) was obtained in pure planting system and 40 plants/m2 density at 0% of herbicide concentration in 50-40 cm layer. The interactions of herbicide application and cultivation system and also herbicide application and planting density were significant on bean yield and with increasing the herbicide concentration and plant density, bean seed yield increased. Based on the results of weed biomass analysis, imazapapir alone was able to reduce weed biomass up to 65%, and this was increased up to 75% under mixed cropping system and increase in density conditions. This suggests that increasing crop competitiveness by increasing plant density and using a mixed crop system instead of a single-crop system, can reduce weed biomass through faster and greater crop formation.

One of the negative effects of herbicide residuals is their phytotoxicity on subsequent susceptible crops in rotation. In order to study the phytotoxic residue effects of triasulfuron +dicamba (Lintur® WG70%) on 12 rotational crops, four experiments were carried out at field research stations of Khorasan razavi (Mashhad), Khuzestan (Ahwaz), Fars (Darab) and Golestan (Gonbad-Kavous) provinces in Iran. Rotational crops were planted in sprayed plots (with 170 g Lintur®) or in control plots (without spraying) immediately after wheat harvesting (as second crop) or in autumn. The rotational plants were selected from the summer crops including maize, cotton, mung bean, sesame and soybean, and fall crops including sugar beet, canola, clover, wheat, barley, faba bean and green pea. Results of t-student test showed the significant negative effect of triacsulfuron+dicambba residues on maize at Mashhad, Ahwaz and Darab in terms of root and shoot dry weight and yield (14.6 to 63% yield reduction). Damage to mung bean was significant in Ahwaz and Gonbad (5.6% -29% yield loss). Sesame yield in Ahwaz decreased 46% and soybean and green pea yields in Gonbad decreased by 12% and 16%, respectively. Rapeseed yield was damaged only in Ahwaz (31%) but in Mashhad, Darab and Gonbad the herbicide damage was not significant. Autumn planted sugar beet was significantly damaged in Ahwaz (46% yield) and in Gonbad (5%). The interval between herbicide application and emergence of summer crops was 90-146 days and for autumn crops was 222-311 days, depending on the rotational plants and experimental regions. Herbicide residue of triasulfuron + dicamba did not have significant damage on cotton, clover, wheat, barley and faba beans in related experiments.

To study the effect of herbicides on weed control in henna in south Kerman province, an experiment was carried out in randomized complete blocks design (RCBD) with 3 replications in 2014-2015 and 2015-2016. Treatments included trifluralin (Treflan, 48% EC) at 2 and 2.5 Lha-1, per-transplant, pendimethalin (Stomp, 33% EC) at 3 and 4 Lha-1 pre weed emergence and after transplanting, imazethapyr (Pursuit, 10% SL) at 0.5, 0.6, 0.7 and 0.8 Lha-1 + Cytogate at 1 Lha-1 at 2 to 4 leaf stage of broadleaf weeds + haloxyfop –R- methyl- ester (Gallant, Super 10.8% EC) at 750 ml ha-1 in the 3 leaf stage of narrow-leaf weeds, gramoxone (paraquat, 20% SL) at 3 Lha-1 and 10 -15 cm stage of weeds with protection cover over henna, hand weeding and weed free. Results of combined analysis in three-cutting henna showed that herbicide applications significantly reduced density and dry matter of amaranth (Amaranthus viridis), purslane (Portulaca oleracea) and Egyptian grass (Dactyloctenium aegypticum. The Best treatments for weeds control was the imazethapyr (0.8 ha-1), pendimethalin (4 Lha-1) and trifluralin (2.5 Lha-1) applications, respectively. Application of imazethapyr (0.8 ha-1) + haloxyfop decreased amaranth (69-76%), purslane (68-74%) and Egyptian grass (60-73%) biomass. Also, this treatment increased henna biomass in the first, second and third harvest by 90, 76 and 79 %, respectively. Therefore, this treatment is introduced as the superior treatment.

A split-factorial experiment was conducted in a randomized complete block design with three replications in a landscape of Qom in 2018. The main factor was the time of herbicide application in spring and summer and sub-factors were factorial combination of 1052.5 g ai.ha-1 2,4-D+MCPA (U46 Combi Fluid, SL 67.5%), 600 g ai.ha-1 Bromoxynil octanoate + MCPA + ethylhexyl ester, 15 g ai.ha-1 tribenuron methyl, and 1132 g ai.ha-1 bentazone + dichlorprop and 0.3% of dioctyl sulfosuccinate sodium salt and oleic acid ethoxylate adjuvants and ammonium sulfate (VI) and the control treatment. Results showed that although some treatments caused an effective loss in dandelion dry weight, they also caused severe damage to the lawn. Mixing oleic acid ethoxylate or sodium sulfosuccinate with ammonium sulfate with bentazone + dichloroprop in the spring resulted in the reduction of the dry matter of dandelion from 337 in the control treatment to 81.6 and 100 g.m-2, respectively. Also, mixing oleic acid ethoxylate and ammonium sulfate with tribenuron methyl in summer reduced dandelion dry matter from 298 in the control treatment to 113 g.m-2, which had the least damage to the grass compared to other treatments.