mohammadhasan rashedmohassel

In order to manage narrow-leaved weeds in wheat fields, an experiment was to investigate the effect of five adjuvants on the efficiency of different doses of Pinoxaden herbicide (EC 5%) in controlled of avena ludoviciana and Lolium rigidum accessions. experiment as a factorial experiment in a completely randomized design with four replications in greenhouse of Plant Protection Institute in 2020. Factors consists of five adjuvants (Ino Alg NPK, Ino Alg NPK (NG), Torpedo and amino acid leucine), 2-included different doses of pinoxaden (including doses of 37. 2, 46.2, 56.7 and 72 g.a.h-1 (Pinoxaden) 3- included of Avena ludoviciana and Lolium rigidum accessions (susceptible and resistant). Weed results showed that adjuvants used in this experiment with Pinoxaden did not show a negative effect on wet and dry weight loss of wheat. Also, with increasing dose of Pinoxaden , control of weed populations increased. Among Adjuvants the use of Ino AlgNPK (NG) adjuvants with fresh weight loss of 93.69 and 87.39% ( populations of Avena ludoviciana, respectively) and amino acid leucine with fresh weight loss of 96.48 and 80.78% (Lolium rigidum, respectively) with a dose of 72 g.a.h-1 had highest reduction in fresh weight loss compared to control. in terms of EWRC index and dry weight loss percentage, no significant difference was observed between doses and adjuvants used in control of these two weeds. results showed amino acid adjuvants leucine and Ino AlgNPK (NG) is recommended to increase effectiveness of Pinoxaden in controlling the weeds of Lolium rigidum and Avena ludoviciana, respectively.

A few herbicides have been registered to control broadleaf weeds in Iran. Sulfonylureas are dual purpose herbicides to control narrow and broadleaf weeds, but these herbicides control narrow-leaf weeds better than broadleaf weeds. Hence, it is better to mix these herbicides with other broadleaf herbicides by different site of action to control broadleaf weeds effectively. Although the most of herbicide mixtures have been antagonism, but studies have shown that phenoxy herbicides have supplementary effects on broadleaf weeds in mixture with sulfonylureas.
In order to study the effect of nicosulfuron rimsulfuron (Ultima) in mixture with 2,4-D MCPA (U46 Combi Fluid) on redroot pigweed (Amaranthus retroflexus L.) at the four-to six-true leaf stage, an experiment was done in 2012 at the greenhouse of Agricultural Faculty of Ferdowsi University of Mashhad, Mashhad-Iran. Experiment was performed as a randomized complete block design with seven rates of herbicide mixtures and four replicates. The plants were sprayed using a greenhouse bench sprayer equipped by 8002 single nozzle with an even spray pattern delivering 200 L ha-1 at 300 kPa and boom height of 50 cm. Herbicides doses in mixture were considered based on effective dose required for 50% reduction in aboveground dry matter of redroot pigweed in pre-test experiments and joint action model calculations. ED50 doses of nicosulfuron rimsulfuron and 2,4-D MCPA applied alone were 22.33 and 55.98 g a.i. ha-1, respectively. The ratio of the herbicides in binary mixtures were 100:0, 87.5:12.5, 75:25, 50:50, 25:75, 12.5:87.5 and 0:100. The dose-response curves in binary fixed-ratio mixture were fitted simultaneously within each treatment using a three-parameter Gompertz model (with the lower limit equal to zero) available in the drc add-on package to the R programme. A Box-Cox transform-both-sides approach was performed to achieve variance homogeneity. The goodness-of-fit was assessed by graphical analyses of residuals and F-test for lack-of-fit. The results of dose-response curves of herbicides in mixture by 50 and 90 percent reduction in aboveground dry matter of redroot pigweed were plotted on the graph and compared to the ADM isobole. Points above the isoboles indicate that the joint action of a mixture is lower than predicted by ADM, while points below the isoboles indicate a joint action higher than predicted by ADM. In the present study, we examined whether the predicted ED50 and ED90 doses of the herbicide mixture was contained in the 95% confidence interval of the estimated ED50 and ED90 doses. This approach inevitably overestimates the number of significant deviations, because it does not incorporate a variation around the isobole. Significant deviations were termed antagonism if higher and synergism if lower than the corresponding estimated ED50 and ED90 doses. As the results with the herbicide mixtures originate from this experiment, it was necessary to standardize the x- and y-axes so that the ED50 and ED90 doses of the herbicides applied separately were always fixed to 1.
Results revealed that 2,4-D MCPA in mixture with nicosulfuron rimsulfuron has lower effect on redroot pigweed in comparison with where herbicides applied alone. So that all of observations were located outside of isobole line, irrespective of response level and strong antagonism was observed in mixture of two herbicides. Interference was observed more especially in mixtures that nicosulfuron rimsulfuron ratios was higher than or equal with 2,4-D MCPA. In these mixture ratios, observations were located far from isobole line at ED50 and ED90 response levels in comparison with higher mixture ratios of 2,4-D MCPA. There may be interference between two herbicides in mixture for absorption into and translocation to site of action. Herbicides formulation and adjuvants may be led to increase or decrease in efficiency of herbicides in mixture according to ADM. Studies have shown that formulation of one herbicide in mixture has important effect on active ingredient absorption of herbicides into the plants. Therefore, it is possible plants have had a chance to detoxify herbicide molecules in mixture at the same rates that herbicides applied alone. Hence, it was required higher rates in mixture to reach an effective dose at the site of action by 50 or 90 percent reduction in aboveground dry matter of redroot pigweed. Therefore, the efficiency of herbicides has been reduced in mixture compared to applied herbicides alone.
Mixture of 2,4-D MCPA with nicosulfuron rimsulfuron does not recommend to control of this weed, because impose more herbicides rates to environment. Therefore, other binary mixtures must be evaluated using nicosulfuron rimsulfuron in mixture with synthetic phenoxy herbicides or other broadleaf herbicides.

A survey was conducted to study the effects of soil and climatic factors on distribution of weeds in 48 parks in 22 districts of Tehranin 2014. 52 weed species from 21 plant families were identified. Multivariate analyses with canonical correspondence analysis (CCA) showed that changes in the weed species distribution were due to soil traits (pH, Phosphorus, Nitrogen, Potassium, %Carbon, %Organic matter, EC) and environmental conditions during previous years. Green foxtail (Setaria viridis), hairy crabgrass (Digitaria sanguinalis), ragweed (Kochia scoparia) and knotweed (Polygonum patulum) had a wide distribution in the areas with high temperature. Where the soil nitrogen were high, Green foxtail (Setaria viridis), Ragweed (Kochia scoparia), Ladino clover (Trifolium repense), Knotweed (Polygonum patulum) and Sow thistle (Sonchus oleraceus ) density was found frequently. Besides, there was a correlation between soil potassium and the density of Broad leaf plantain (Plantago major L.), Little hogweed (Portulaca oleracea), Watter grass (Echinochloa crus-galli), Procumbent yellow-sorrel (Oxalis corniculata) and Common dandelion (Taraxacum officinale) in turfgrasses. Based on the results of this study, it would be possible to overcome these problems to some extent by predicting future problems of weeds and changing management plans.

Potato (Solanum tuberosum) is an annual crop that belongs to the Solanaceae family. It contains abundant starch and ranks as the world’s fourth most important food crop, after maize, wheat and rice. It is one of most important crops in Iran. The total area under potato cultivation was 186 thousand hectares during 2011 and 2012. Weeds are one of the greatest limiting factors to efficient crop production. Application of herbicides is the key method of weed control in potato fields, both in the world and Iran. Herbicides that commonly are used for weed control in potato fields of Iran are metribuzin, paraquat, rimsulfuron, pendimethalin and sulfosulfuron.
In order to study the effect of herbicides to control weeds of potato fields, field experiments were conducted at the Agricultural Research Center of Jiroft and Karaj. Plots were located on a sandy loam soil with a pH of 7.4 in Jiroft, and loamy soil with a pH of 7.7 in Karaj. The experiments were conducted during 2009-2010. Potato variety used in Jiroft was Santeh and Satina in Karaj. The experimental design was the randomized complete blocks design (RCBD), with four replications. Weed control treatments included paraquat (20% SL) at 3 lit/ha as early post- emergence, metribuzin (70% WP) at 750 gr/ha as preemergence, pendimethalin (33% EC) at 3 lit/ ha as preemergence, rimsulfuron (25% DF) at 60 gr/ha applied with adjuvant cytogate at 2.5% volume of water early post emergence, sulfosulfuron (75% DF) at 35 gr/ha (postemergence), metribuzin at 750 gr/h rimsulfuron at 60 gr/ha with adjuvant cytogate at 2.5% volume of water, , metribuzin at 750 gr/ha pendimethalin at 3 lit/ ha, metribuzin at 750 gr/ha sulfosulfuron at 35 gr/ha, paraquat at 3 lit/ha rimsulfuron at 60 gr/ha with adjuvant cytogate at 2.5% volume of water, paraquat at 3 lit/ha pendimethalin at 3 lit/ha, paraquat at 3 lit/ha sulfosulfuron at 35 gr/ha and hand weeding. Each plot was 4 m wide and 8 m long with 4 rows and 75 cm distance among rows. Density and dry weight of weeds and potato yield were recorded.
Results indicated that 6 broadleaf weeds were dominant in the fields included prostrate pigweed (Amaranthus blitoides), bindweed (Convolvulus arvensis), malva (Malva neglecta) in Jiroft, and red rooted pigweed (Amaranthus retroflexus), datura (Datura stramonium), bladder hibiscus (Hibiscus trionum) in Karaj. Visual observation confirmed that the most weeds were effectively controlled using herbicide treatments. The statistical analysis of the data revealed that the herbicides applied for weed control in potato have significantly decreased weed density and dry weight. The lowest weed density and dry weightof prostrate pigweed were observed in plots treated with paraquat rimsulfuron. This treatment reduced density and dry weight of prostrate pigweed by 70% and 69% in Jiroft. However, Red rooted pigweed was controlled better than prostrate pigweed in Karaj. All treatments of mixed herbicides reduced density and dry weight of red rooted pigweed by 100% in Karaj. Maximum control of bindweed was obtained with metribuzin rimsulfuron. This treatment reduced density and dry weight of bindweed by 35 % in Jiroft. The highest control of malva was achieved with metribuzin plus rimsulfuron in Jiroft. This treatment reduced density and biomass of malva by 61 and 56%, respectively. The best control of datura was obtained with paraquat plus rimsulfuron in Karaj. This treatment reduced datura biomass by 98%. Maximum control of bladder hibiscus was obtained with paraquat plus rimsulfuronin which dry weight was reduced by 98%. The highest potato yield (48 ton/ha) was obtained by application of metribuzin plus rimsulfuron in Jiroft. Potato yield was also increased with this treatment by 40%. The least potato yield (32 ton/ha) was obtained with pendimethalin in Jiroft. The maximum potato yield (32 ton/ha) was obtained by application of paraquat plus rimsulfuron and paraquat plus pendimethalin in Karaj, and minimum potato yields were obtained by application of sulfosulfuron and pendimethalin.
Results of both years and locations showed that application of herbicide mixture improved weed control and potato yields. Pendimethalin and rimsulfuron are suitable alternatives for herbicide rotations in potato fields and can replace metribuzin and paraquat.

To evaluate the sensitivity of different crops included some pulses to simulated metribuzin soil residues, an experiment was conducted in completely randomized design with factorial arrangement and four replications in Research Greenhouse of College of Agriculture, Ferdowsi University of Mashhad. Treatments included of 8 crops (chickpea, common bean, lentil, corn, wheat, barley, rape seed and sugar beet) and concentrations of metribuzin simulated residue in soil at 6 levels (0, 0.016, 0.032, 0.064, 0.128 and 0.160 mg a.i. kg-1 soil). Plants survival percentage and shoot and root biomass were measured 30 days after emergence. Plants response to metribuzin soil residue fitted with 3 and 4 parameters logistic equations to the shoot and root biomass data as a function of the herbicide soil residue concentrations and was used to calculate the dose for 50% of measured traits (ED50). Results showed that the survival and shoot and root growth were affected by metribuzin soil residue, significantly (pchickpea>common bean>corn.

In order to study different arrangements and weed controls effects on mung bean (Vigna radiate L. Wilczek) – black cumin (Nigella sativa L.) intercropping an experiment was conducted at the Research Station of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during growing season 2005 – 2006. Sixteen treatments comprising combinations of eight sowing patterns [A1: Sole black cumin, A2: Sole mung bean, A3: 3 rows black cumin– 2 rows mung bean, A4: 3 rows black cumin – 2 rows mung bean, A5: 2 rows black cumin – 1 rows mung bean, A6: 1 row black cumin – 2 rows mung bean, A7: 3 rows black cumin – 3 rows mung bean (Striped), A8: 1 row black cumin – 1 row mung bean (alternative rows)] and two weed controls [V1: unweeded, V2: completely hand weeding] were arranged in a factorial experiment based on randomized complete block design with three replications. Results showed that in intercropping systems leaf area index (LAI) of mung bean reduced but in the case of black cumin increased. Mung bean total dry matter in intercropping system did not differ comparing with sole crop but total dry matter in black cumin increased. All yield components in both crops affected by sowing patterns and weed control treatments. Number of branches/plant, number of pods or follicules/plant and number of seed/pods or follicules increased in A8, A4, A5 and A3 sowing patterns in mung bean and A3, A5 and A7 sowing patterns in black cumin compared with other arrangements. By increasing mung bean ratio in rows, the number of weed species, weed density, dry weight of weeds and abundance of weed species decreased. In unweeded treatment, number of branches/plant, number of pods or follicules/plant and number of seed/pods or follicules decreased in both crops. Land equivalent ratio (LER) was more than 1.00 in all sowing patterns.

During 2005 and 2006, fourteen and seven Phalaris minor populations were found in the wheat fields of Fars and Golestan Provinces, respectively, that exhibited resistance to fenoxaprop-P ethyl and diclofop methyl belonging to the aryloxyphenoxy propionate herbicides. Seed bioassay was conducted at the weed science laboratory of Ferdwosi University of Mashhad to study the resistance of the populations to the APP herbicides. Petri dish assay showed that the populations are resistant to applied herbicides with different level of resistance. Using the estimated parameters of concentration-response curves, discriminating concentration was determined for diclofop methyl at 8.04 ppm and for fenoxaprop-P-ethyl at 1.05 ppm. A study was also conducted at the agricultural biochemistry laboratory of Cordoba University to investigate the biochemical basis of resistance to ACCase–inhibiting herbicides in the resistant populations. In vitro enzyme assays revealed a herbicide-resistant ACCase enzyme in the AR, MR4 and SR3 populations. Extracted ACCase enzyme from the shoots of these populations was highly resistant to both applied herbicides compared with the susceptible population. The results suggest that the mechanism of resistance to APP herbicides in the three most resistant populations (AR, MR4 and SR3) relates to an altered ACCase. In the case of the rest of the resistant populations, other mechanisms including enhanced metabolism, lack of absorption and translocation, and other unknown mechanisms may be involved. These results also confirmed seven populations are cross-resistant to both the herbicides studied.