جستجوی مقالات مرتبط با کلیدواژه « خردل وحشی » در نشریات گروه « کشاورزی »

In the national standard for canola seed production, wild mustard is considered an illegal weed. Although canola and wild mustard can be distinguished by the morphological traits, it is not possible to distinguish the seeds of two species, especially the coated seeds. The present study was conducted to optimize the identification and detection of wild mustard seeds in rapeseed lots by morphological, chemical and molecular methods. The other seed count test was performed according to the rules of international seed test in rapeseed sampling. Chemical test design was performed under KOH treatment. The results of the chemical test were presented in five different status. Three specific markers of DA, DC and 5S rDNA were used, respectively. The Cruc marker is thought to be an internal control. Multiple polymerase chain reaction show amplification patterns of wild-mustard seed-specific markers with 5S rDNA amplified 190 bp that did not amplify in canola seeds. DA and DC markers in canola seeds amplified 239 and 625 bp, respectively, which did not amplify in wild mustard. According to molecular specific Profile and comparison with different status of rapeseed. Morphological limitation features and similarity of expression states of seed-related traits in wild mustard and rapeseed and factors such as seed coverage and chemical treatment restriction of wild mustard from rapeseed masses according International seed testing will not be possible, in which case DNA-based molecular tools will provide reliable results.

Knowledge on germination ecology of weeds in response to salinity and drought stresses can help to predict weeds population dynamics in the future. Among the family of weeds, the weeds of Brassicaceae family include many important species that contaminate crops and orchards. In addition to the presence of weeds, salinity and drought are also considered as limiting factors in agricultural production. Due to the increase in salinity and drought stresses in agricultural fields, it can be significant expansion and contamination of Brassicaceae weeds, because Physiological dormancy, abundant seed production and emergence at different time, leads to be persistent for long-term in soil. Therefore, the aim of this research was to compare the characteristics of seed germination of four weeds Brassicaceae family to salinity and drought stresses.

In order to investigate the effects of salinity (0, 50, 100, 150, 200, 250, 300, 350 and 400 Mm) and drought stress (0, -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa) on seed germination four Brassicaceae family weeds (Rocket (Eruca sativa), Hoary Mustard (Hirschfeldia incana), Wild Mustard (Sinapis arvensis) and Treacle Mustard (Erysimum repandum), two experiments as factorial based on completely randomized design (CRD) were conducted at agricultural sciences and natural resources university of Khuzestan in 2019 with three replications. Optimum Temperature for germination were selected 25°C for Rocket, Hoary Mustard, Wild Mustard and 15°C for Treacle Mustard. Duration of test for two experiments was considered 15 days. Criterion for germination was length radicle 2-3 mm.

By increasing drought stress, germination, vigour index and germination rate were decreased and no germination was observed in drought stress of -1.2 MPa. 50% reduction for germination in four weeds Rocket, Hoary Mustard, Wild Mustard and Treacle Mustard were estimated in -1, -0.49, -0.76 and – 0.41 MPa of drought stress respectively. Drought stress required to reduce 50% of germination rate for Rocket, Hoary Mustard, Wild Mustard and Treacle Mustard were estimated -0.85, -0.35, -0.28 and 0.22 MPa respectively.The vigour index of Wild Mustard in conditions without drought stress treatment was more than other weeds. Rocket and Hoary Mustard were introduced as resistant and Wild Mustard was introduced as sensitive to salinity. The salinity required to reduce 50% of germination for Rocket, Hoary Mustard, Wild Mustard and Treacle Mustard were predicted 267, 162, 39 and 46 mM, while 50% reduction for germination rate were 174, 142, 27, 44 Mm respectively. By increasing salinity and drought stresses, mean germination time was increased and maximum mean germination time belonged to Treacle Mustard and the reason for this increase was the lag phase of germination. Germination rate in four weeds was more affected by salinity and drought stresses than germination percentage. Generally the germination rate of Treacle Mustard was much less than other weeds. So that the maximum germination rate of Treacle Mustard was 5 seed/day in control treatment while in Rocket Hoary Mustard, Wild Mustard were more than 30 seed /day.

According to the results, in saline lands, the spread of two weeds Rocket and Hoary Mustard is more expected and in the conditions of drought stress and in rainfed agriculture, presence of Rocket is more evident than Wild Mustard.

Weeds such as wild mustard are a serious problem in crop production. Herbicide resistance in weeds and wild mustard has become a common threat in agriculture and endangers global food security. In this experiment, the ALS gene of wild weed suspected of weeding due to field screening and PCR-based methods from Kermanshah provincechr('39')s wheat fields was investigated. The ALS gene was then identified, isolated and cloned. For this purpose, primers were designed according to the information available in the NCBI database and ALS gene was amplified using RT-PCR. The gene ALS cloned in pTZ57R / T vector within E. coli bacteria, DH5α strain and sequenced. Based on PCR-based molecular results, six biotypes showed mutations in the target site. PCR-based sequencing results confirm the nucleotide mutations of Asp376-Gly (GAC to GGC), Pro197-Ser (CCT to TCT), Trp574-Leu (TGG to TTG), and Ala122-Thr (GCA to ACA) in six biotypes. These mutation sites were confirmed by sequencing. According to the study, herbicide resistance in wild mustard could be related to resistance in the target site due to the mentioned nucleotide mutations in the active site of the enzyme, the binding site of ALS inhibitors and its family, or due to the resistance of the target site that can cause conformational changes. Changes in the level of the protein reaction site with herbicides and as a result changes in activity and enzyme-herbicide binding. This means that the molecular levels of the mutant enzyme are less likely to come into contact with herbicides, and the herbicide cannot stop the enzyme from working and cause herbicide resistance.

Sugar beet competes with weeds for light, nutrients and water resources and is so sensitive especially at the early stages of growth. Weeds are the most important factors limiting sugar beet production in Iran. Although, about 20 herbicides were registered to control weeds, but their effectiveness would be high only if farmers use them properly. Due to sensitivity of weeds to herbicides at certain times, determination of the best herbicide application time is very important. Cloridazon is one of the selective herbicides registered for broadleaf weeds control of sugar beet. Both pre and post-emergence applications of this herbicide were recommended but the effectiveness of treatment should be evaluated. 

In order to determine the best application time of Cloridazon (Pyramin, WP 65%) to control broad leaf weeds in sugar beet field, an experiment was conducted in two locations i.e. Golestan province (Gonbad station) and Khozestan province (Safiabad, Dezful station), Iran, during 2018. Experiments were arranged as randomized complete block design with 4 replications. Treatments were: application of Cloridazon at 3, 4 & 5 kg/ha, and two different application times (i.e. pre-emerge and post-emerge at 4 leaf stages), application of Phenmedipham+Desmedipham+ Ethofumesate (Betanal Progress O.F. at 3 lit/ha at 2-4 leaf stages), and weed free as the check. Each experimental plots were divided into two parts including: uncontrolled part (as weedy control) and treatment part. Efficacy of the treatments on weed population and control was evaluated based on the percent of reduction in weeds density and dry weight and EWEC scoring system at 30 days after herbicides application. Root yield of sugar beet was also measured at the end of the growing season. The weed spectrum was not similar in both locations. Polygonum aviculare and Sonchus arvensis were dominant in Gonbad and Malva sylvestris and Sinapis arvensis were dominant in Dezful. Experimental data were analyzed by SAS (version 9.1) program and means were compared with the Duncan's multiple range test.

The results indicated that the effects of treatments on weeds were significant. Application of Cloridazon at 3 kg/ha controlled sinapis arvensis by 95 to 100% and Sonchus arvensis by 86 to 93%. In both locations, the difference between this treatment and Phenmedipham+ desmedipham+ ethofumesate (Betanal Progress OF) was not significant. Chloridazon (as pre-emergence treatment) performed better in controlling broad leaf weeds compared with post treatment. The pre-emergence application of Chloridazon (at 3 , kg/ha) was the best treatment (with more than 85% weed population control) in both studied areas. In addition, this treatment had no significant difference with Phenmedipham+ desmedipham+ ethofumesate (Betanal Progress OF). The results show the low efficacy of Pyramin on weeds when it was applied late (after 2 leaf stages). However, due to different germination time of weeds, single application of Pyramin is not enough to achieve the desired results. Application of post-treatments (like Betanal Progress OF) is necessary as complementary treatments. However, using 3 kg/ha of Pyramin, cannot control Malva sylvestris if this weed is dominant in the field, and the Pyramin dose should be increased to 4 kg/ha. Anyway, application of Chloridazon at more than 4 kg/ha is not recommended as it would have negative effects on sugar beet seed germination. It should be noted that both cultivars (Roza Gold and Silvetta) used in Gonbad and Dezful were monogrm and more sensitive to herbicides with respect to polygerms. The probability of seed damage on monogrm cultivars will be higher by pre emerge herbicide application. Based on our results, application of Chloridazon (at 3 kg/ha as pre-emerge treatment) was the best treatment for sugar beet root yield and showed no significant difference with the application of Phenmedipham+desmedipham+ ethofumesate (Betanal Progress OF).

Oilseed rape (Brassica napus L.) is one of the valuable oilseed crops which has been attracting attention in recent years (Arvin et al., 2011). Several factors such as water shortage, low relative humidity, heat and salinity can make drought stress. Radiation use efficiency and yield components are the effective factors of yield formation in oilseed rape. Drought tolerance in oilseed rape depends on other factors except radiation use efficiency. Studies have indicated that plant growth promoting rhizobacterias (PGPRs) has a direct effect on growth and they can cause resistance to the abiotic stress as well. Hence, considering the drought climate in Iran and the effects of PGPRs on increasing resistance to abiotic stress and relief of drought effects and the importance of the cultivation of oilseed rape in Iran, the present research was done with the goal of study of drought and some plant growth promoting rhizobacteria (PGPR) on radiation use efficiency and dry matter partitioning into pod in different cultivars of oilseed rape.
The current study was done on the basis of two simultaneous experiments (under stress and non-stress experiments) during 2010- 2011 growing season at Agriculture and Natural Resources Research Station of Torogh, Mashhad is in East-North of Iran (36° N, 59° E, 1003 as).Two research sites (under stress and non-stress fields) were beside each other. This region has a semi-arid climate (annual rainfall 286 mm). The experimental design was factorial based on randomized compeletly block design with three replications in each experiment. The first treatment was plant growth promoting rizobactria, including B0: no inoculation (control), B1:co-inoculation (Pseudomonas flourescens 169. putida 108), B2: inoculation with P. flourescens 169 and B3: inoculation with P. putida 108. Second treatment was cultivar, including Hayola401 and Hayola330 cultivars belong to Brassica napus, Parkland and Goldrush cultivars belong to B. rapa and BP18 and landrace cultivars belong to B.juncea . Radiation use efficiency and the allocation coefficient of materials to pods were measured in the present study as well. In addition, analysis of variance (ANOVA) was performed using SAS ver. 9.1 software.
Radiation use efficiency There were significant differences between stress and non-stress conditions in levels of bacteria, cultivar and bacteria × cultivar regarding radiation use efficiency. The outcomes showed that the coefficients of radiation use efficiency in each level (bacteria, cultivar and bacteria × cultivar) under non-stress condition was comparatively higher under stress condition. The interaction effects of bacteria × cultivar showed that P. flourescens× Goldrush under non-stress condition with 0.62±0.08 dm.mg-1 had the most and two strains of bacteria× Landrace with 0.1±0.017 dm.mg-1 had the least radiation use efficiency. Regarding bacteria level, Pseudomonas flourescens under non-stress condition with the average of 0.39±0.071 dm.mg-1 had the highest radiation use efficiency. Hayola330 cultivar with 0.45±0.047 and Hayola401 cultivar with 0.39±0.038 dm.mg-1 obtained the greatest RUE under non-stress condition and BP18 cultivar with 0.11±0.06 dm.mg-1 revealed the lowest RUE under stress condition. Both drought stress and simultaneous application with two strains of bacteria had negative effects on RUE.
Dry matter partitioning into pod In this trial, considerable difference regarding pod partitioning coefficient revealed in the level of cultivar and bacteria × cultivar. The value of the pod partitioning coefficient under this investigation ranged from 0.9393± 0.084 under non-stress condition to 0.1634± 0.0210 under stress condition. Although inoculation treatment of bacteria had the synergy effect, co-inoculation treatment had the antagonistic effect of pod partitioning coefficient. Moreover, the rate of the pod partitioning coefficient lessened under drought condition. Berry & Spink (2006) and Arvin et al. (2014) stated that there were positive correlation between HI and partitioning photoasimilate in to economic organs. The results of the present study showed that dry matter partitioning into the pod with a final yield had a 91% positive correlation under non-stress and 74% under stress condition.
In conclusion, negative effects of drought and positive effects of application of bacteria on RUE and pod dry matter partitioning were obtained in this trail. The results illustrated that separate application of bacteria had synergy effect and conflation of two strains of bacteria had an antagonistic effect on both studied traits.

For determination of economic damage threshold of four wheat (Triticum aestivum L.) cultivars in different densities of wild mustard (Sinapis arvensis L.)، experiments were conducted at Agricultural Research Station Gorgan during 2010-2012. The experimental design consisted of four randomized complete blocks in a factorial arrangement. The treatments comprised of factorial combination of wild mustard densities and wheat cultivars. Five different densities of wild mustard (zero، four، eight، 16 and 32 plants. m-2) and four wheat cultivars (‘Arta’، ‘Tajan’، ‘Mogan’ and ‘Morvarid’) were considered in all the replications. Cousens hyperbolic equation was used to describe the yield reduction due to wild mustard competition. The maximum yield reduction was associated with high densities of wild mustard and among the cultivars، ‘Arta’ and ‘Morvarid’ had the maximum and minimum yield reductions، respectively. Calculated competitive indexes indicated that ‘Morvarid’ cultivar in competition with wild mustard had a high capacity to prevent yield loss (high tolerance) and on the other hand، dry weight and seed amount of weed was also greatly reduced. Using extended Cousens hyperbolic model and Odonovan formula، economic damage threshold for wheat in two years determined in densities of 4. 11، 3. 68، 2. 33 and 2. 11 plant/m2 for ‘Morvarid’، ‘Moghan’، ‘Tajan’ and ‘Arta’ cultivars in climatic conditions of Gorgan.

This research was conducted to study the relative fitness of wild mustard biotypes of Khoozestan, Golestan and Kermanshah provinces that are resistant to Acetolactate Synthase (ALS) Inhibitors. Green-house experiments were conducted in two parts. In the first part, plant dry matter, leaf area and plant height change of resistant and susceptible biotypes of each province were compared under no competition with wheat condition. In the second part, growth ability of resistant and susceptible biotypes of each province, growth ability and yield of wheat were studied under competition conditions. According to the results, resistant biotype Ker-2 had significantly higher than susceptible biotype Ker-1, but there was no significant difference between them on the point of final height and dry weight per plant. Resistant biotypes of Golestan and Khoozestan (Kh5 & G3) were lower than susceptible biotypes of these provinces (Kh3 & G9) on the point of mentioned three criteria, significantly under competition with wheat condition. Resistant biotypes of Ker-2 and susceptible biotypes of Ker-1 had no significant difference on the point of ability of competition with wheat. Relative interference index of the two biotypes of Kermanshah were not significantly, different. Finally, difference of growth and yield of wheat were not significant in competition with these two biotypes. According to the results of Golestan and Khoozestan, susceptible biotypes of them (Kh3 & G9) had significantly higher growth and interference index than resistant biotypes (Kh5 & G3) in competition with wheat. Also, wheat had higher grain growth and yield in competition with resistant biotypes rather than susceptible biotypes. Finaly, results showed that among the three resistant biotypes, only Ker-2 had the same competition and growth ability to susceptible biotypes. Therefor it, could disperse rapidly and make high interference due to its resistance to ALS inhibitors.

Allelopathic phenomenon is an interference method of weed on crops that can help to know crop-weed interaction. This experiment was conducted to evaluation of Sinapis arvensis and Cirsium arvense allelopathic effects on canola germination and nutrient uptake in 2007 at greenhouse of University of Mohaghegh Ardabili. Treatments were differential concentrates (0, 2.5, 5, 10, 20 and 40%) of fresh and dry residual extract of Sinapis arvensis and Cirsium arvense. The experiment was laid out as factorial in completely randomized design. Analyses shown that fresh and dry extract of two weeds reduced germination of canola in compared with control 1.5 to 2.5 times. Also fresh and dry extract of weeds reduced canola dry aboveground mass. Nitrogen and P uptake reduced under fresh extract, while dry extract of Sinapis arvensis increased p uptake in canola more than 4 times. Fresh and dry extract of Sinapis arvensis and Cirsium arvense increased canola K concentrate. The experiment results show that in addition to competing weeds, through release of chemicals can be also inhibit on growth and physiological processes of crop.

This experiment was conducted to study the effect of salinity and drought stress on germination and growth characteristics of wild mustard seedlings collected from irrigated wheat fields on the base of a complete randomized design in Iranian Plant Protection Research Institute. Different levels of salinity and drought stress included of 0 (control), -2, -4, -6, -8 and -10 bar were created by NaCl and poly-ethylene-glycol (PEG), respectively. Measured criteria included of final germination percentage, germination speed, seedling length, plumule length, radicle length and seedling vigor index. According to the results, mentioned stresses had negative significant effect on germination rate and percentage, length of plumule, radicle and seedling and seedling vigor index. More significant effect in drought stress than salinity stress showed higher resistance of wild mustard in salinity stress rather than drought stress. Both salinity and drought stress affected length of plumule more than length of radical. It means that length of plumule is more sensitive to mentioned stresses. According to fitted model, X50 (the potential caused to 50% reduction of final germination and germination rate of wild mustard) related to salinity stress (7.33 and 5.03, respectively) was significantly higher than X50 related to drought stress (4.47 and 2.90, respectively).

To investigate the factors affecting the population density of weeds and yield loss of them in wheat, a non systematic survey experiment was conducted in 45 fields in the township of Bandar-gaz (Sarmahaleh village) in 2012. Sampling of wheat and weeds were taken in two stages (Heading and Harvest maturity) by randomized to the five points of each field using quadrate size 1m*1m. In this study all information about crop management including Land area, farmers experience, the seed bed preparation, sowing date, cultivar and site preparation of them, sowing ways, seed rate, weeds control ways, kind, amount and time of herbicide, fungicide use and wheat harvest time were collected during a growing season by preparing questionnaire and complete them with farmers. At the end of the growing season, the actual yield harvested by farmers’ recorded. Among the various parameters, Wheat plant and raceme density, farmer experience, Kind of variety and use of Tapic+Geranestar herbicide had significant effects on weed population. With increased wheat plant density, weed density decreased. Also there was less weed density in field of high experience farmer. Weed density was lesser in N8118 variety than N8019 variety and not use Tapic+granestar herbicide due to increased of weeds density. Among weed different species, Avena sp, Phalaris minor and Sinapis arvense had highest negative effect on wheat yield. Model study showed if wheat plant density was optimum and there were weeds, yield will be 2713kg/ha and if weeds remove yield will increase to 2877kg/ha (yield gap equal164kg/ha). Amaong weed, Phalaris minor (12 plant per m-2), Sinapis arvensis (3plant per m-2) and Avena sp (2 plant per m-2) with 65, 18 and 17% yield loss respectively, were the strongest competitor with wheat.

The aim of this study was to investigate and to quantify the effect of burial depth on seedling emergence of volunteer canola and wild mustard. Seeds were buried in 12 different depths (1، 2، 3، 4، 5، 6، 8، 10، 12، 15، 20، 30 cm) in 4 replications and seedling emergence was measured daily. Results indicated that emergence percentage of volunteer canola was around 98 % from 1 to 2. 9 cm of burial depth and deeper depths decreased emergence percentage with a slope of -0. 4 and reached to zero in burial depth of 10 cm. Seedling emergence percentage of wild mustard was described using an exponential model on the response to burial depth. According to the model، wild mustard seedling emergence decreased from 66 % in 1 cm depth to 0 % in 8 cm depth. Increasing burial depth leads to reduction of seedling emergence rate that it well quantified for both species. Seeds of these two species that buried in deeper soil layers from 10 cm for volunteer canola and 8 cm for wild mustard can expand soil seed bank and will not emerge. The results of this study may provide useful information in ecological weed management and prediction seedling emergence of weeds.

In order to evaluation of relation between weed dynamic and utilization of nitrogen in weed as influence of integrated fertilizer management in different weed densities، a field experiment was carried out in experimental farm of Agricultural Faculty of Shahid Chamran university of ahvaz at 2011-2012 growing season. Experimental design was based on a split-plot with three replications. Main plot was 5 integrated fertilizer managements and sub plot was 3 weed densities. Our results showed that the treatment 75% chemical fertilizer whit Biological fertilizer in lower weed density had the highest weed density and dry weight. Narrow leaf and broad leaf weeds was dominant species in 100% chemical fertilizer and 100% biological fertilizer Treatments، respective. Also، weed diversely was reduced by reduction. So، Treatment 100% biological fertilizer had the highest weed density nitrogen fertilizer utilization efficiency was increased by reduction of nitrogen chemical fertilizer. In addition، all nitrogen useefficiency. Indices were more affected by nitrogen chemical fertilizer، than weed density. Based on our results،increasing dependence to biological fertilizer، will reduce is the compatibility of wheat plant، in early growth period، which caused increasing in density and decreasing of weed at the wheat growth period.

In four separate experiments, competition of different densities of feral rye (Secale cereale) and wild mustard (Sinapis arvensis) with wheat (Sayson cv.), also interference of Canada thistle (Cirsium arvens) and wild mustard with canola (Okapi cv.) were evaluated in 2008-2009 growing season, in Bu-Ali Sina University of Hamedan. Rectangular hyperbolic model, yield reduction of both crops than weed density and dry weight described properly. Increased dry weight of each three weed species than density per unit area was linearly. In interference with wheat, initial slope of yield loss (I) and economic threshold (ET) of wild mustard competition than feral rye were more and less, respectively. Inhibiting effect of Cirsium arvens on canola was more than wild mustard and had less economic threshold. Increasing dry weight of wild mustard per unit area instead of per plant, in competition with canola was less than wheat. Also ET of this weed in wheat was obtained more than canola. Except for experiment of Cirsium arvens interference with canola, in other cases when weed dry weight as criterion of yield loss was used, higher coefficient of determination (R2) and less residual mean square (RMS) than weed density was obtained. These results showed that weed dry weight, in comparison with density, was often better indicator of competitive ability and negative effects of weeds on crops. Also wild mustard interference with wheat was more competitive than feral rye. But its interference with canola showed less competitive ability as compared with broad leaf weed of Cirsium arvens.

In order to study the effects of wild mustard density on grain yield and yield components of canola cv. Hyola 401 under different rates of nitrogen fertilizer، a field experiment was conducted in 2011-2012. The layout was split-plot in a completely randomized block design and three replications. Main-plots included four levels of nitrogen (0، 70، 140 and 210 kg ha-1) and sub-plots consisted of different wild mustard densities (0، 6، 12، 18 and 24 plants m-2). Results showed at densities of 6، 12، 18 and 24 wild mustard. m-2، grain yield losses were 15. 5%، 36. 7%، 47. 4% and 58. 6%، respectively. Grain yield loss was due to reduction in number of grains per plant and 1000-grain weight. Agronomic N use efficiency (ANUE) of canola decreased as the weed density increased. The highest ANUE was obtained in 70 kgNha-1، without weed interference. The lowest ANUE was in 210 kgNha-1 and 24 wild mustard plant. m-2 treatment. Generally، application of 140 kgNha-1 lead to higher competitiveness and lower grain yield loss in canola compared with 0 kgNha-1، whereas، in 210 kgNha-1، the negative impact of 12 wild mustard. m-2 and above on canola grain yield، was higher than other N treatments.

To find methods of breaking seed dormancy,an experiment was arranged in a factorial experiment based on a completely randomized design with three replications in laboratory ofGorgan University of Agricultural Sciences and Natural Resourcesduring 2010. The seeds were divided into three portions. Two portions of seeds within a period of two and four weeks in temperature of 4οC was remained uniformity under moist conditions (cold stratification) and one another part of seeds located in laboratory conditions and ordinary temperature. Then nine mechanical and chemical scarification treatments (using of gibberellic acid with concentration of 500, 1500 and 2000 ppm; 1, 2 and 4 minutes soaking in sulfuric acid; 1, 2 and 3 minutes of using of Emery)were applied on these seed portions and the germination percentage, rate and uniformity were investigated. Also, in order to determine the effect of treatments on permeability of seed coat to water, water adsorption trend of wild mustard (Sinapis arvensis) seed was studied after using of treatments. Results of experiment indicated that prechilling, scarification treatments and their interaction effects have significant effect on germination components. According to results, effective treatments following by 24 hours of soaking in gibberllic acid(density=2000, 1500 ppm) andmechanical scarification for 2 minutes treatment, in non-prechilling and 2 weeks prechilling. No use of prechilling treatment, germination percentage in 24 hours of soaking in gibberllic acid(density=2000, 1500 ppm) andmechanical scarification for 2 minutes treatment observed 58.5, 56 and 47.5%, respectively. Despite two weeks of moist chilling, germination percentage of these treatments with a slight increase was about 77.25, 76.5 and 53.25%, respectively, meanwhile under four weeks of moist chilling, germination percentage in above treatments decreased about 77, 65 and 66%. In the end it became clear that the best treatment for reduction of wild mustard seed dormancy and improve its germination was 24 hours of soaking in gibberllic acid(density=1500 ppm) andemery for 2 minutes treatment

In this research, seed germination modeling of wild mustard was conducted satisfactory. Beta function was used to describe seed germination rate to temperature. Base temperature was -2.9 oC and it was increased with decreasing water potential to about 2 oC in -0.6 MPa. The R2 values were 0.86 in sub-optimal temperatures, and this value for supra-optimal temperatures was 0.94. The R2 values showed a good fitness of the hydrothermal time model under both sub- and supra-optimal temperatures. The hydrothermal values were 207 and 274 MPa oC for sub- and supra-optimal temperatures, respectively. The parameters and relationships estimated here can be used in soil seed bank dynamics models or can be use to establish a new model for the environment. The results of this study will also be useful for future studies of wild mustard biology and ecology.

In this study the effects of osmotic potential of water and drought stress on seed germination and seedling emergence of wild mustard (Sinapis arvensis) ecotypes were studied. The seeds were collected from four provinces including Fars, West Azarbaijan, Khoozestan and Mazandaran. Trials were carried out to study the effects of osmotic potential of PEG-6000 solutions at seven levels (0, -0.01, -0.05, -0.25, -0.1, -0.5, -1.5 MPa) on seed germination of four populations of wild mustard. In addition, the seedling emergence pattern of the populations was investigated in response to three soil moisture regimes (field capacity (FC),FC–1/3FC–FC, FC–1/6FC–FC) on percent weed emergence in a greenhouse. Results showed the highest germination occurred at 0 MPa osmotic potential. Germination gradually decreased by reducing the osmotic potential to -1.5 MPa. The trend was different among the ecotypes. The most number of germinated seeds was observed at high soil moisture (field capacity). The seeds of all ecotypes were sensitive to drought stress. Seed undr drough stress transformed to secondary dormancy and hence returning to field capacity did not induce germination.