asieh siahmarguee

The use of medicinal plants has been done since ancient times and may even be considered the origin of modern medicine. Medicinal plants are a source of biomolecules with therapeutic potential and as a lead to develop new drugs. Black cumin (*Nigella sativa* L.), often referred to as a "miracle herb," is a medicinal plant that has been used worldwide for centuries in the treatment and prevention of diseases such as cancer and diabetes. Additionally, it has been valued as a spice and flavoring agent in products like bread and sweets. Various factors influence the growth and yield of black cumin per unit area, with planting date being particularly significant. The timing of planting affects environmental conditions during the plant's growth stages, influencing the rates of vegetative and reproductive growth, and ultimately impacting yield. Therefore, selecting the appropriate planting time is crucial for the successful cultivation of any crop, including black cumin. The aim of this research is to determine the most suitable planting date of black cumin for this plant and the response of different ecotypes of this medicinal plant to the planting date in the weather conditions of Gorgan city.

In order to evaluate different ecotypes of black cumin in response to planting date in Gorgan, a field experiment with four planting dates was carried out in the cropping year of 2020-2021 at the research farm of Gorgan University of Agricultural Sciences and Natural Resources, Iran. The experiment was carried out in the form of split plots based on completely randomized block statistical design with three replication, in which four planting dates were 18th December, 17th January, 16th February and 18th March as the main plot and thirteen ecotypes (Such as Tafaresh, Gardmiran, Razan, Hamedan, Arak, Esfahan, Semirom, Eqlid, Ashkazar, Zabol, Bajestan, Sarayan and Khaf) with 3 replication were considered as sub-plot. In this research, the attributes of plant height, number of branches per plant, number of follicles per plant, number of grain per follicle, weight of 1000 grains and grain yield were measured. After harvesting, measurements were taken and then the data were analyzed with SAS 9.4 statistical software and means comparison was done with LSD’s test in significance at 5% probability level. Graphs were prepared using Excel software.

The results showed that the interaction effects of planting date and ecotype on plant height, number of branches per plant, number of capsules per plant, number of grains per capsule and 1000- grain weight were significant. However, the main effects of planting date and ecotype on grain yield were significant, and the interaction effects were not significant. With the delay in planting, all measured traits decreased. The highest grain yield was obtained from the first planting date (December 18) with 1245 kg per ha. The highest grain yield was obtained from Khaf (1245 kg.ha-1), Sarayan (1179 kg.ha-1), Bajestan (1156 kg.ha-1), Zabol (1141 kg.ha-1) and Esfahan (1117 kg.ha-1) ecotypes. In contrast, the lowest grain yield was obtained from the fourth (March 18) planting date with 694 kg.ha-1. The lowest grain yield was obtained from Arak and Gardmiran ecotypes with 903 and 890 kg.ha, respectively. With the delay in planting, the grain yield of high-yield ecotypes decreased linearly (8-9 kg.ha for each day of delay in planting), with the difference that the decrease in grain yield in the Bajestan ecotype (5.8 kg.ha for each day of delay in planting) was less than other ecotypes, which indicates the high adaptability of this ecotype to the planting date and environmental conditions of Gorgan. Also, there is a positive and significant correlation between grain yield and traits of plant height (0.73**), number of branches per plant (0.56**), number of follicles per plant (0.83**), number of grains per follicle (0.84**) and 1000- grain weight (0.55**).

In general, the results of this research showed that planting date and ecotype have a significant effect on black cumin yield, and it is recommended to plant high-yield ecotypes in December to obtain higher grain yield in Gorgan and additional tests should be done in this area for final confirmation.

White morning glory (Ipomoea lacunose L.) is one of the weeds that have recently spread in the fields of Golestan province and has become a serious challenge for farmers. In this study, the effect of different environmental conditions, including constant temperature, alternating temperature, water stress, salinity, high temperature, and burial depth on the germination and emergence of three seed populations of this plant collected in 2018, 2019, and 2020 (at the time of the experiment, these seeds were after-ripped 15, 3, and 0 months, respectively) were investigated. All experiments were conducted based on a completely randomized design with three replications. The results showed that the response of germination to the studied environmental factors was different in seed populations. Germination percentage started at 10°C and increased with increasing temperature. Although the germination percentage was significant at 40°C, it was completely stopped at 45°C. Alternating temperature compared to constant temperature increased the germination in the range of low temperatures; however, there was no difference with the constant temperature in the high-temperature range. The water potential required to reduce 50% of germination in the seeds of 2018, 2019, and 2020 was -0.83, -0.82, and -0.43 MPa, respectively. The tolerance of this species to salt stress was much higher than to water stress, and the increase of salinity up to the potential of -1.1 to -1.4 MPa reduced its maximum germination by 50%. Increasing the high temperature to 80 and 100 °C stimulated the germination, and no seeds survived at 120°C. In the populations of 2018 and 2020, the emergence percentage of seeds increased with the increase of burial depth; so that it reached its maximum value at a depth of 3 cm. By increasing the burial depth, the percentage of seedlings emergence of these populations decreased and stopped at a depth of 9 cm. The seedlings emergence of 2019 population also happened with the same process (but in smaller numbers), but no seedlings emergence occurred at a depth of 5 cm. In general, the results of this study showed that the reaction of white morning glory germination to environmental factors is different. Knowing the germination response of this species against the mentioned factors can help predict the germination and emergence of this plant to design suitable management strategies.

This study was performed to investigate the effect of nitrogen fertilizer levels and pre-planting of cover crops on some vegetative traits and yield of rice plants.

This was conducted over 2017-2018 and 2018-2019, at the research farm of Sari University of Agricultural Sciences and Natural Resources. The experimental design employed a three-replicated split-plot arrangement within a randomized complete block design. The main plots involved five nitrogen consumption levels (0, 120, 240, 320, and 400 kg ha-1). The sub-plots included four types of pre-planted cover crops (no cover crop, canola, bersim clover, and rye).

Based on the findings, employing berseem clover as a cover crop in pre-sowing resulted in a significantly more favorable rice yield than others. Nitrogen fertilizer at rates of 320- 400 kg ha-1 led to enhanced vegetative traits, yield, and various yield components, including leaf area index and tiller number, ultimately resulting in increased overall yield. Results revealed that planting bersim clover cover crop before planting rice, along with 320 kg ha-1 of urea fertilizer, leads to 41.5% higher yield compared to no fertilizer).).

Bersim clover stood out among the pre-planting cover crops, significantly enhancing many rice traits. Additionally, no significant difference was observed between urea fertilizer levels of 320 and 400 kg ha-1 in several measured traits. Thus, the integrated treatment of bersim clover cover crop and 320 kg ha-1 of urea fertilizer is recommended before planting rice.

Wild rye (Secale cereale) is considered one of the most important winter cereal weeds in the world. The damage resulting from the interference of this weed with wheat is more than other species of weed. This species is known as the most important wheat weed in the southern highlands of Golestan province (Shahkouh region). Since the area under wheat cultivation in the southern highlands of Golestan province (Shahkoh region) is much lower compared to the plains and low-altitude areas, no attention has been paid to the problems of wheat production, including the presence of Wild rye in the mentioned region.

This experiment was designed and carried out as a survey method in 30 wheat fields at Alvand and Omid cultivars in Shahkoh region of Golestan province. Sampling was done from each field in the wheat harvest stage at ten points in quadrats measuring 1 x 1 square meter. All wheat and wild rye plants were harvested at each point and transferred to the Plant Physiology Laboratory of Gorgan University of Agricultural Sciences and Natural Resources to determine plant density, yield and yield components.

The results showed that the number of wild rye plants in the fields varied from 0 to 9 plants per square meter. The number of spikes. m-2, grain yield and biomass yield of wild rye in all densities were higher in interference with Alvand cultivar than Omid cultivar. With increasing the density of rye, the studied traits decreased in wheat cultivars. With the introduce of each rye plant, the number of spikes.m-2, number of seeds per spike, 1000-seed weight, seed yield, biological yield and harvest index were 6.64%, 3.50%, 2.47%, 9.28%, 5.38% and 9.43% in Omid cultivar and 4.74%, 4.19%, 2.93%, 7.30%, 3.77% and 7.15% in Alvand cultivar, respectively. A lower decrease in the number of spikes.m-2 and 1000-seed weight in the Alvand cultivar can indicate its higher competitive power compared to the Omid. On the other hand, the seed yield of these cultivars in terms of non-interference with wild rye in fields under self-consumption seeds was almost similar to fields under certified seeds (without contamination with rye).

These findings showed that wild rye has an important role in reducing the yield of wheat cultivars in Shahkooh region; Alvand cultivar is considered as a more suitable cultivar due to its higher yield potential in both interference and non-interference conditions; The use of certified seeds may be the main strategy to control wild rye in Shahkuh region.

The different species of Amaranthus species are among the most important damaging weeds in the world. Due to the importance of studying the effect of management factors on seed dynamics of different weed species, this experiment aimed to investigate the effect of burial depth and high temperatures on the seed dynamic of different species of Amaranthus in Golestan province including white pigweed (A. albus), prostrate pigweed (A. belitoides), hybrid Amaranthus (A. chlorostachys), redroot pigweed (A. retrofelexus) and green Amaranthus (A. viridis) were performed.

This research was conducted on five amaranthus species of white pigweed, prostrate pigweed, hybrid Amaranthus, redroot pigweed, and green Amaranthus at the seed laboratory and greenhouse of Gorgan University of Agricultural Sciences and Natural Resources. In the first experiment, seed emergence of different species of Amaranthus was studied in eight burial depths including 0, 1, 2, 3, 4, 5, 7, and 10 cm. In the second experiment, seeds were exposed to 50, 60, 70, 80, 90, 100, and 110 °C temperatures for 5, 10, and 15 minutes

All seeds of A. blitoides and A. viridis germinated in the topsoil (zero depth); But, in A. albus, A. retroflexus, A. chlorostachys, 93%, 83%, and 3% of the seeds were emergence at the soil surface, respectively. By increasing the burial depth to one centimeter, the percentage of seeds emergence in different species of Amaranthus decreased significantly and was negligible at ≥ 2 cm depth. Germination test performed on retrieved seeds showed that zero to 16% of the seeds were able to germinate in petri dish, and most of the non-germinated seeds were viable. In all species except for A. chlorostachys high temperatures reduced the germination percentage.

Due to the reduction of seed germination percentage of different species of Amaranthus from a depth of more than one centimeter of soil, it seems that the use of conservation and conventional tillage methods has a good potential to reduce infestation of fields by these weeds. Also, although high temperatures reduce weed infestation in fields, they do not have a significant effect on depleting the seed bank of these species.

Highlights:

1- Seed dynamics of different species of Amaranthus were affected by burial depth and high temperature
2- Deep burial of seeds of different species of Amaranthus causes the stability of their seeds in the soil seed bank.

Reports indicate the invasion of two species of Ivy-leaved morning-glory (Ipomoea hederaceae Jacq) and Asian spider flower (Cleome viscosa L.) to summer crops fields such as soybeans in Golestan province. Considering the importance of knowing the cardinal temperatures of germination in the models for predicting the presence of weeds and consequently designing correct management strategies on these plants, this experiment was conducted to study the germination behavior and to compare the cardinal temperatures of germination for two species of Ivy-leaved morning-glory and Asian spider flower under two conditions of constant and alternating temperatures.

In order to study the effects of constant and alternating temperature on the percent, rate and estimating cardinal temperature of germination for Ivy-leaved morning glory and Asian spider flower, two separate experiments as a Completely Randomized Design with four replications were carried out at the seed laboratory of Gorgan University of Agricultural Sciences and Natural Resources. Studied temperature treatments on Ivy-leaved morning glory included the constant temperatures of 10,15,17,20,25,30,35 and 40 oC and alternating temperatures of 12.5:7.5,10:15, 12.5:20, 15:25, 20:30, 25:37.5, 30:42.5 and 35:45 oC. Temperature treatments on Asian spider flower included the constant temperatures of 15, 20, 23, 25, 28, 30, 35, 40, 45 and 50 o C and alternating temperatures of 15:20, 20:25, 20:30, 25:30, 25:35, 30:40, 30:45, 30:50 and 40:50 oC.

Results indicated that alternating temperatures had a positive effect on the germination of Ivy-leaved morning glory, which increased from 78% at constant temperatures to 94% at alternative temperatures. However, the maximum germination percentage of Asian spiderflower at the alternative temperature of 20:30 was 79%, which had no significant difference with a constant temperature of 30 with 84% germination. The base temperature for seed germination of Ivy-leaved morning glory at alternating temperatures (10.09 oC) was a little lower than that of constant temperatures (11.25 oC). But in Asian spider flower, the base temperature at alternating temperatures (17.57 oC) was more than that of constant temperatures (15.43 o C).

The most important factor in the occurrence of such different responses to constant and alternating temperatures in Ivy-leaved morning glory and Asian spider flower is their adaptation to environmental conditions and their survival in highly degraded agricultural environments. These two weeds are warm-season plants and their seeds enter the soil seed bank in autumn. The presence of dormancy (regardless of its type) in the seeds of these two plants prevents the germination of their seeds in winter; and the experience of alternating temperatures at this time prepares the seeds for germination in the spring. The base temperature of Ivy-leaved morning glory was not much different under the constant and alternating temperature conditions. But the base temperature of Asian spider flower was higher under alternating temperatures compared with constant temperatures.

Common morning-glory (Ipomoea purpurea L.) is one of the most important harmful weeds in summer crops in Golestan province. Germination is one of the most important stages of plant life and the study of environmental factors affecting the germination of weeds is necessary for their proper management.

In order to investigate the effect of some environmental and management factors on seed germination and emergence of common morning-glory, experiments were conducted in the laboratovar and research greenhouses of the Gorgan University of Agricultural Sciences and Natural Resources in 2017. In this study, common morning-glory response to constant temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 ° C), alternating temperature (5:15, 10:20, 15:25, 20:30) , 25:35), high temperature (temperatures of 50, 80 and 100 ° C for 5 and 10 minutes), drought (0, -0.2, -0.4, -0.6, -0.8, -1 MPa), salinity (0, -0.2, -0.4, -0.6, -0.8, -1, -1.2 and -1.4 MPa), pH (4, 5, 6, 7, 8, 9), burial depth (0, 1, 2, 3, 5, 7, 9, 11, 13, 15 and 17 cm) and flooding duration (0, 3, 5 and 7 days) were examined.

Constant and alternating temperatures had a significant effect on the germination percentage of common morning-glory. The highest germination percentage were observed at constant temperatures of 30 and 35 °C and at alternating temperatures of 15: 25 and 20: 30 °C (day / night). Based on the Dent model, Cardinal temperatures of seed germination of this plant including base, optimum upper and lower and ceiling temperatures were 7, 30, 35 and 44 °C, respectively. Germination of of common morning-glory seeds decreased with increasing salinity and drought. The concentrations of sodium chloride and polyethylene glycol, which reduced the germination of this plant by 50%, were equal to -1.06 and -0.45 MPa, respectively. This indicates that this plant is resistant to salinity and there is a possibility of its development in saline lands of the country. Germination of this plant in pHs of neutral and alkaline were significantly higher than acidic pHs. At high temperatures, the percentage of germination and seed viability decreased significantly. The percentage of common morning-glory seed emergence at burial depths of 1 to 7cm were not significantly different (92 to 100%). With increasing depth from 9 to 13 cm, the percentage of emergence decreased significantly and no seeds emerged from a depth of 15 cm. Therefore, the use of non-tillage and low tillage methods can not have much effect on the management of this weed; Unless deeper plowing is used. Results showed that seed germination of this plant is very sensitive to flooding stress.

The results of the present study showed that environmental factors have a significant effect on the germination and emergence of common morning-glory and they can be used in designing effective management scenarios to control of this weed.

Germination is the most vital period in the plant life cycle that is influenced by various environmental and genetic factors. Among environmental factors, drought stress can greatly affect the germination and emergence of seedlings. The tolerance to this stress in the early stages of plant development is very important and seeds that can germinate in these conditions will have a successful establishment, proper density and high yield. Therefore, knowing the drought tolerance threshold in different genotypes of a plant can be very useful in recommending their cultivation in different regions. The hydrotime model is one of the common experimental models in studying the effects of drought stress on seed germination. This model has three parameters including base water potential, hydrotime coefficient and sigma, which indicate drought tolerance, germination rate and germination uniformity, respectively. These coefficients, especially the base water potential, can be used to introduce genotypes for cultivation in areas with different drought levels. Therefore, this study was conducted to investigate the response of different quinoa genotypes to drought stress at the germination stage with the help of hydrotime model coefficients.

To investigate the effect of drought stress on seed germination of different quinoa (Chenopodium quinoa Willd) genotypes, a factorial experiment was designed and conducted in a completely randomized design with four replications in the seed laboratory of Gorgan University of Agricultural Sciences and Natural Resources in 2019. For the germination test, 4 replicates of 25 seeds of each genotype were placed in a petri dish with a diameter of 8 cm on a layer of filter paper which added 3 ml of solutions prepared in different water potentials (0, -0.4, -0.8, -1.2 and -1.6 MPa) in an incubator at 25 °C. Depending on the germination rate, in the first days after the onset of germination, the number of germinated seeds was counted three to five times per day; with decreasing the germination rate, the number of counts was reduced to two times per day. The germination criterion was the radicle existence of one millimeter or more. The hydrotime model was used to investigate the germination response of quinoa genotypes to drought stress.

The results showed that all genotypes had high germination up to -0.4 MPa and their average germination percentage was above 90%; But as the water potential became more negative, the difference between the germination percentage of genotypes increased. According to the hydrotime model, there was a significant difference between different quinoa genotypes in terms of base water potential for 50% germination (ψb50), hydrotime coefficient (θH) and germination uniformity (σψb). The value of the ψb50 parameter ranged from -1.58 in genotype2 to -1.95 in genotype3. This indicates that quinoa is drought tolerant at the germination stage compared to sunflower, barley, wheat, safflower and canola. The lowest and highest hydrotime coefficients were observed in genotypes2 and 3 with 16.83 and 26.08 MPa/h, respectively (with an average of 20.93 MPa/h). Quinoa hydrotime coefficient is lower than rapeseed, wheat and safflower; In other words, the germination rate of the seeds of this plant is higher compared to the mentioned crops. The reason for this may be related to the size of the seed. The lowest germination uniformity was in genotype 3 (0.68 MPa) and the highest value observed in genotype 7 (0.46 MPa). The hydrotime and sigma coefficients are considered as indicators of germination rate and uniformity. The lower values of these coefficients are indicated the higher the germination rate and uniformity of the genotype, the faster the canopy closure and the higher yield.

In general, the results of this study show that the seeds have a high germination rate and with a high tolerance to drought stress at the germination stage; This increases the chances of faster establishment in the water shortage conditions. Also, the ability to tolerate drought in the germination stage of quinoa reduces the need for water consumption in this stage, which can be very useful and practical in developing management plans that lead to increased water use efficiency.

Dodder is a one of the major parasitic weeds in the world. Dodder infestations reduce crop yield and increase harvesting costs. Different methods have been suggested to control of dodder, but none of them have been able to control these plants reliably. It seems that using resistant varieties is the best option to achieve this goal. In this study, resistance of 15 varieties of tomato to dodder infection (Cuscuta campestris Yunck.) were investigated under greenhouse conditions. Among these varieties, two susceptible and resistant varieties (Supra Urbana and Super Chef, respectively) were selected and catalase, guaiacol peroxidase, ascorbate peroxidase, total phenolic compound, proline, flavonoid and soluble sugars was evaluated at different times after infection (0, 24, 48, 72, 96, 120 and 240 Hours). The results showed that dodder infection increased the enzymes concentration (catalase, guaiacol peroxidase, ascorbate peroxidase) compared to the non- infection treatment. Also, the amount of these enzymes in resistant cultivar were higher than susceptible cultivar. Variety and sampling time affected on total phenol content, proline, flavonoids and soluble sugars. Total phenolic compound and flavonoid levels increased after attaching the dodder to the tomato and reached its highest level at 240 h after attachment. This results indicates the induction antioxidant defence system in tomato under dodder infection. The results of this study show that contamination of tomato with dodder induces the immune system in this plant. Given that it is not possible to perfect control of parasitic weeds without crop damage, it can be very useful to know the defence mechanisms by which cultivars resistant to parasitic plants stand.

The present experiment was conducted to study the resistance of winter wild oat biotypes in wheat fields and mapping the distribution of its biotypes resistant to clodinafop propargyl, diclofop methyl and fenoxaprop P ethyl in Kalaleh township. Samples included 105 suspected resistance winter wild oat accessions were collected in June of 2014 from 150 wheat fields of Kalaleh township. The coordinates of the sampling points were recorded by a GPS. A susceptible sample was also collected from a region with no spraying history. Screening of accessions was done with discriminating concentration of three herbicides. The results showed that among the suspected resistant accessions, 27.60, 24.76 and 23.81% were resistant to clodinafop propargyl, diclofop methyl, and fenoxaprop P ethyl, respectively. Among the suspected resistant accessions 4, 7 and 11 biotypes were resistant only to clodinafop propargyl, diclofop methyl, and fenoxaprop P ethyl, respectively 3.81, 6.67 and 11.47% out of 105 suspected resistant accessions. Eight biotypes showed cross-resistance to both clodinafop propargyl and diclofop methyl which was equal to 7.62% of suspected resistant accessions. Eleven biotypes equal to 11.47% of total accessions showed cross-resistance to diclofop methyl and fenoxaprop P ethyl, 12 biotypes equal to 11.43% of suspected resistant accessions showed cross-resistance to all three herbicides, and only one biotype was cross-resistant to clodinafop propargyl and fenoxaprop P ethyl which was equal to 0.96% of total accessions. Finally, the distribution map of resistant weed-infested fields was generated using geographic information systems.

The majority of the country's oil consumption comes from foreign sources. Therefore, the development of oilseed crops is critical. Safflower has a special status among oilseed grains adapted to the country's conditions, and it is ecologically compatible with many agricultural lands in the country. Research has shown that planting date and plant density significantly affect the yield and yield components of crops. Over the past few years and in different Iran regions, several cultivars have been isolated from safflower, which may vary in response to planting date and plant density. Therefore, this study was conducted to study and determine the most suitable planting date and plant density for the advanced safflower cultivars and their effect on grain yield, forage, oil, and yield components in the Gonbad-e Kavus area.

This study was conducted with two separate factorial experiments (the first experiment on 30th of November and the second on 20th of December) in a randomized complete block design with four replications at the Agricultural and Natural Resources Research Station of Gonbad-e-Kavus in two seasons of 2013-14 and 2014-15. In each experiment, two sowing densities of 20 and 40 plants per square meter (10 and 20 cm plant distance on the row) and four advanced safflower cultivars included: Golmehr, Soffeh, Padideh, and Goldasht, were combined as factorial and formed eight treatments. Seeds of the mentioned cultivars were prepared from the Golestan Agricultural and Natural Resources Research and Education Center. The row spacing was fixed at 25 cm for all treatments. SAS software was used to analyze the data, and the mean comparison of the data with SPSS software was performed as the least significant difference (LSD) test.

The results showed that the effects of planting date on the branch number plant-1, grain yield, oil percentage, forage ash, and the dry matter intake were significant. The influences of sowing density on branch number plant-1, 1000-seed weight, and oil percentage were significant. There were significant differences among the cultivars according to the branch number plant-1, and safflower seed oil percentage. The mean comparison of data showed that the highest branch number plant-1, grain yield, forage ash, and the dry matter intake were observed in the first planting date, and the delayed sowing decreased these traits significantly, while oil percentage showed a significant increase. Increasing the sowing density induced the branch number plant-1, 1000-seed weight, and oil percentage significantly. The forage yield showed a positive significant with grain yield and crude protein.

In terms of safflower planting date, it was observed that the first planting, due to suitable climatic conditions and longer growing period, had better results in the branch number plant-1, boll number plant-1, oil content, forage ash, and dry matter intake traits. With increasing plant density, branch number plant-1, 100-seed weight, and oil percentage decreased significantly, so due to the importance of oil content, 20 plants per square meter is recommended. According to this study's results, the Soffeh cultivar could be used for the earlier sowings, but there was no significant difference in grain yield among the cultivars with delayed sowing. So, four studied cultivars Golmehr, Soffeh, Padideh, and Goldasht, could be cultivated under the delayed planting date conditions, and it is suggested that selection of safflower cultivar should be made according to the purposes of safflower planting (forage, oil, or seed breeding).

In order to investigate the soybean competitive ability (DPX cultivar) under interference condition different densities of Asian spider flower (0, 3, 5, 10, 15, 20, 30, 45 plant/m-2); an experiment was conducted based on randomized complete blocks design with three replications in 2015–2016 growing season in Kalaleh, Golestan province. Different densities of Asian spider flower had a significant effect on biological yield, economic yield, 100 grain weight and pods per plant of soybean. The highest grain and biological yields of soybean were 374.9 and 734.30 g/m2, respectively which observed in weed-free treatment. However, these traits declined nonlinearly as weed density increased, so that in 45 plant/m-2interference treatment, economic and biological yields reached 172 and 344.38 g/m2, respectively.

Contamination of wheat seeds in southern Golestan province (Shahkooh village) with rye has rendered it a weed in wheat fields. Due to the lack of suitable herbicides, it is very difficult for farmers to control weed-rye. According to observations, many farmers use rye-infected self-consumed wheat seeds for cultivation. Separation of rye seeds from wheat seeds is very difficult due to their similarity in appearance, and farmers are not aware of the possibility of seed separation. Therefore, this study was conducted to compare the physical properties of rye and wheat seeds to improve seed separation.

Rye seeds were collected from wheat fields in Shahkooh village. The seeds of Alvand wheat cultivar, which is a common cultivar in Shahkooh region, were also obtained from Shahkooh Rural. The studied physical properties included seed size (seed length, width and thickness), seed surface area, seed weight, spherical percentage, bulk density, true density, porosity percentage, angle of repose and coefficient of friction. Physical properties of the seeds were studied at five seed moisture levels including 10, 15, 20, 25 and 30%.

Based on the results, the length, width and surface area of both wheat and rye seeds were not affected by seed moisture. Only in wheat, seed thickness increased with increasing seed moisture content. Since these properties determine the final seed size, it can be said that the seed size remained almost constant by increasing the percentage of seed moisture in these two plants. On the other hand, in all moisture levels, the width, thickness and surface area of wheat seeds were higher than those of rye seeds. In contrast, seeds length of rye was longer than wheat seeds. In wheat seeds, the spherical percentage increased linearly by increasing seed moisture content, but its amount was constant in rye at different seed moisture content. The significant difference between the spherical percentage of wheat and rye seeds also indicates that the wheat seed is more spherical compared to rye at all moisture levels. The seed weight increased linearly with increasing seed moisture content in both wheat and rye plants, with a higher slope in wheat than rye. In addition, wheat seed weight was higher than rye seed weight in all moisture levels. The existence of these differences in the dimensions, the shape and weight of wheat and rye seeds can be considered as the basis for their separation. In wheat and rye plants, the bulk density, true density and percentage of seed porosity decreased linearly by increasing seed moisture content. Also, the bulk density and true density in wheat was higher than in rye at all moisture levels. With an increase in seed moisture from 10 to 30 percent, the porosity percentage in both wheat and rye plants decreased by about 14 percent on average, and there was no significant difference between them in terms of the percentage of porosity at different moisture levels. An increase in the percentage of seed moisture caused a linear increase in the angle of repose. In other words, the ability of seeds to move was reduced by increasing the moisture content in two wheat and rye plant. There was no significant difference in the angle of repose between wheat and rye at any of the moisture levels. In this study, the coefficient of friction in wheat and rye seeds linearly increased on different materials by increasing seed moisture content. There was no significant difference in the coefficient of friction on galvanized iron and cement surfaces at different moisture levels between wheat and rye. However, the coefficient of friction in wheat was always higher than rye on plastic, wood and rubber surfaces. Due to these differences, it is easy to remove rye seeds from wheat seed lots and prevent rye from re-entering the wheat fields during planting.

According to the results of this study, there is a significant difference between wheat and rye seeds in terms of physical characteristics. These differences facilitate separation of rye seeds and avoid entry into wheat seed lots. The difference in the length, width, thickness and density of the seeds in these plants makes it possible to use length or width based separators, air screen machines and gravity separators.

More than twenty years after registration of tribenuron methyl herbicide in Iran, there are reports on its lack of efficacy in controlling broad leaved weeds in wheat fields of Ramiyan Township. To investigate the occurrence of resistance to tribenuron methyl in wild mustard (Sinapis arvensis L.), a series of experiments were conducted at Gorgan University of Agricultural Sciences and Natural Resources in 2016. Putatively resistant wild mustard biotypes were gathered from wheat fields of the Township. A susceptible biotype was also gathered from the fields with no history of spraying. Putative biotypes were first screened with the recommended dose. Then, response of susceptible and resistant biotypes to various doses of tribenuron methyl herbicide was investigated. The results of dose-response assay implied occurrence of resistant to tribenuron methyl in some wild mustard biotypes. Resistance factors of RAM-R-14, RAM-R-27, RAM-R-25, RAM-R-30 and RAM-R-5 were obtained respectively 3.90, 4.10, 3.96, 2.66 and 2.36. Distribution map of fields infested with susceptible and resistant wild mustard biotypes was drawn using geographic information system and it was revealed that the gathered biotypes were observed in the fields which possessed unsuitable cropping pattern and weed management was based on chemical control. The results of the present study may be utilized to implement herbicide-resistant weed management practices as well as prevention of development of these plants to other regions.

Findings on mineral nutrient concentration, accumulation and allocation in different parts of crop can help to more accurate planning in order to optimize the mineral nutrition of Plant. Therefore, the present study aims to investigate the effect of phosphorus fertilizer rates (Prate) as 0. 8.4, 16.8, 25.2 and 33.6 mg phosphorous (P) per Kg of dry soil equal to 0, 20, 40, 60 and 80 Kg P.ha-1 and inoculation with P solubilizing bacteria Streptomyces sp. on concentration, accumilation and partitioning of potassium (K) in different parts of wheat and barley in stem elongation (SE), anthesis(Ant) and harvest maturity(HM). This pot experiment was conducted as a factorial experiment in a completely randomized design with four replications in the new campus of Gorgan University of Agricaltural Sciences and Natural Resources during 2014-2015 growing season. Results showed that K concentration ([K]) were significantly influenced by Prate in all plant parts and was increased linearly by increasing the Prate in all three above mentioned growth stages. Also, Inoculation with bacteria increased shoot and total plant [K] in SE and Anth Stage, significantly. There was a significant difference between the two crops for the above traits. The results indicate that increase in Prate and inoculation with bacteria resulted in a significant increase in K accumulation (KCont) in all plant parts, and that two studied crops were statistically different in terms of the leaf and grain Kcont. Also, results showed a significant effect of inoculation with bacteria on Kcont of shoot and total plant in SE, all plant parts in Anth, and all shoot organs in HM. The Kcont in shoot and total plant in SE, all plant parts except stem in Anth, and all shoot organs in HM of wheat was different with barley, statistically. Also, based on the results of this study, the potassium partitioning coefficient to different plant parts in all three stages was more stable compared to [K] and Kcont, and it was much less affected by experimental factors. Finally, there was not significant interaction between the experimental factors almost for all above mentioned traits.

To investigate the factors affecting soybean yield loss in comparison to the attainable yield, an experiment was conducted in 50 fields in the township of Kalaleh in summer of 2016. Sampling of weeds were taken in early growing season of soybean based on W pattern. In this study all agronomic management information including land area, farmers experience, seed bed preparation, sowing date, cultivar and provided seed source, sowing methods, seed rate, weeds control methods, amount and time of applied herbicide and wheat harvest time were collected during growing season by preparing questionnaire and complete them with farmers. In evaluated fields, 13 weed species belonged to 11 families were observed. Among the various parameters, field area, seed rate, certified seed application, planting date, Asian spider flower (Cleome viscosa L.) and Johnson grass (Sorghum halepense L.) had the significant effects on soybean yield. The minimum and optimum predicted yields with model were 1039 and 2036 kg/ha-1, respectively. Thus there was 996 kg/ha-1 gap between minimum and optimum predicted yield in this township. Results showed certified seed (23.07 percent), delay planting date(15.04 percent), low seed rate (11.54 percent), low field area(7.62 percent), present of Johnson grass(12.47 percent) and asian spider flower(30.25 percent) weeds were the most effective factors on this yield gap. With optimizing mentioned agronomic managements could reduce yield gap and increased yield to double.

To design effective weed population control measures, the identification, characterization, and quantification of weed species within a certain area are important steps to form the basis for weed management (Kropff and Spitters 1991). Information on weed density, distribution, and species composition might also help to predict crop yield losses due to weeds and can help determine whether it is economical to control a specific weed problem. The population and seed bank of weeds is very dynamic. The population dynamics of these plants depends on climate and soil factors and farm management practices (Firehun and Tamado, 2006; Kumara et al. 2007; Derksen et al. 2002). Thus, the objectives of this study were to determine the composition and the soil seed bank of weeds in soybean fields in Kalaleh, Golestan Province, and to assess the influence of soil types and major agronomic practices on weed species and the soil seed bank.
This study was performed to assess the influence of crop management practices and soil characteristics on density and composition of weed seedling and the soil seed bank of soybean fields in Kalaleh, Golestan Province, in 2014. Data on crop management practices (rotation, manure and chemical fertilizer used, field area, kinds of herbicide and seeds) and soil characteristics (pH, EC and organic matter) were collected from 200 soybean fields. Samplings of weed populations (seedlings) and the seed bank were carried out at the beginning of soybean growth (before implementing the control) with W method in 50 cm ×50 cm quadrates at 0-10 cm and 10-20 cm depths. Finally, the effects of soil and agronomic practices were investigated on dominant weeds using a multi-variate analysis.
The survey of weed flora in Kalaleh soybean farms showed 16 plant species (belonging to 13 plant families) had infected the farms. The major observed species were Cyperussp (70.60%), Sorghumhalepense L. (45.42%), Ipomoeaspp. (37.19%), Cucumis melo (30.33%), and Cleomeviscosa L. (27.29%). Seeds of 19 species were observed in depths of 0-10 cm. and 20 species were observed in depths of 10-20 cm. The major species observed in both depths were Amaranthus sp., Portulaca oleraceae L., and Cleomea viscosa L. The results of the multi-variate analysis indicated that the effect of crop management and soil factors had different effects on seedlings and the soil seed bank of weeds. Generally, crop management practices had a greater effect than soil characteristics. In this study, herbicides (seedling and seed bank), manure (seed bank) and pH (seedlings) were the major factors that affected weed population and the seed bank.
According to the dominance of five species including Cyperus sp., Sorghum halopenseIpomoea sp.,Cucumis melo and Cleome viscosa in weed flora and the seeds of three species, Amaranthus sp., Portulaca oleraceae and Cleomeviscosa in the soil seed bank, it can be said that the above species contribute significantly to the reduction of soybean yields in this region. The results showed that farmers’ management practices have a greater impact on the weed population and the seed bank than soil factors do.

IntroductionThe food legumes are given high priority in world agriculture because they constitute 2.3 or more of protein in the diet of the inhabitants of the tropics and they are the potential source to fill the protein-gap. Mung bean belongs to plant family Fabaceae, and is the most important pulse crops of the world. It has great value as a food, fodder and green manure. Potential yield of Mung bean can be achieved through optimum use of inputs and agronomic practices. Plant density and suitable sowing time are the most important factors affecting the yield. Plant density is considered as one of the important determinative factors of yield of this plant. The purpose of proper density is more efficient use of the plant from different environmental potential such as water, nutrients, light, etc. to achieve higher yield. Too early sowing may not successfully germinate, while yield from too late sown crop may be low due to unfavorable condition for growth and development of Mung bean. The aim of this study was to determine the optimum sowing date and plant density to achieve maximum performance of the Mung bean in both irrigated and rainfed conditions.
Material & MethodsIn order to evaluate the effects of planting date, plant density and irrigation on yield and yield components of Mung bean (VC-1973A genotype) an experiment was performed in Research Station of Islamic Azad University, Gorgan Branch at 2012. In this study, a factorial experiment in a randomized complete block design with three replications was used. Three planting dates (6 July, 21 July and 6 August) and two densities (12.5 and 25 plant per square meter) were the treatments. The experiments were conducted in two separate conditions of irrigation (at the beginning to flower and pod stages) and rainfed. Dry weight of the seeds in physiological maturity was determined. Also in full maturity, after removing the effect marginal, yield and yield components were calculated. Analysis of variance was carried out using the SAS software. Comparison of means also was performed using LSD test at 5% level and corresponding graphs were plotted with Excel software.
Results & DiscussionThe results of analysis variance showed that both in irrigation and rainfed conditions, there was a significant difference between planting dates in terms of number of pods per plant, seeds per pod, seed weight, biological yield and harvest index. But there was no statistically significant difference for these factors between densities (12.5 and 25 plant/m2). The highest and lowest number of pods per plant, number of seeds per pod and seed weight observed in 6 July and 6 August planting dates, respectively. In irrigation condition, planting dates of 6 July and 6 August had the highest (6400 kg per hectare) and lowest (3614 kg per hectare) biological yield. Also, in rainfed condition, maximum and minimum of biological yield were obtained for planting date of 6 July (4276 kg) and 6 August (2673 kg per hectare), respectively. Planting date July 6th had the highest harvest index under both irrigated (45.3%) and rainfed (38.2%) conditions. Planting date July 6th also had the highest seed yield under both irrigated (2900 kg/ha) and rainfed (1636 kg/ha) conditions. Irrigation in beginning of flowering and pod stages increased seed yield and aboveground dry mater, significantly. Late planting date decreased vegetative stage, caused reducing in pod number per plant and seed number per pod, resulted in reduction of seed yield. The results showed that Mung bean crop has a high production potential under climate condition of the Gorgan.
ConclusionThe results of analysis variance showed that under both irrigation and rainfed conditions, there was significantly differences between planting dates in terms of number of pods per plant, seeds per pod, seed weight, biological yield and harvest index. But there was no statistically significant difference for these factors between densities (12.5 and 25 plant/m2). In both irrigated and rainfed conditions, date of planting 6 July, was the best planting date. The grain yield under irrigated and rainfed conditions were 2900 and1636 kg per hectare, respectively. Irrigation at early flowering and early pod stages, led to an increase in grain yield and dry matter compared to the rainfed conditions. The results showed that this plant has a high production potential in weather conditions of Gorgan. Thus, cultivation of Mung bean in Gorgan is recommended. Moreover, planting date July 6th and density of 25 plants /m2 can be a good choice for Mung bean cultivation in this region.

Cleome viscose Linn. with a common name as “Asian spiderflower”, belongs to the Capparidacea family. It is an annual, sticky herb found as a common weed all over the tropical regions of the world. It is a very competitive weed of annual crops. This plant is currently introduced as an invasive plant in soybean fields of Golestan province. There is no management recommendation to control Asian spider flower. Thus large quantities of soybean destroyed by this weed every year. Germination and emergence are the two most important stages in the life cycle of plants. Environmental factors such as temperature, light, pH, planting depth and soil moisture are known to affect seed germination and emergence of weeds. An understanding of the germination biology of Asian spider flower would facilitate the development of better management strategies for this weed. Therefore, the purposes of this research were to study the effects of temperature and water potential on Asian spider flower seed germination.
Material and To evaluate the effect of temperature and water potential on seed germination and determination of seed germination cardinal temperatures of Asian spider flower, an experiment was conducted as Factorial Experiment in Completely Randomized Design with 4 replications in Agricultural Research and Natural Resources Center of Golestan Province during 2013. Treatments were included temperatures with seven levels (15, 20, 25, 30, 35, 38 and 400C) and water potentials with six levels (0, -2, -4, -6, -8 and -10 bar). Germination was monitored daily until germination discontinued and the number of the germinated seeds was recorded. Seeds were observed twice daily and considered germinated when the radical was approximately >2mm long. To quantify the response of germination rate to temperature and to determine the cardinal temperatures for germination original beta, and modified beta, segmented and dent models were used. Water potential data showed a sigmoid trend and a three-parameter logistic model was fitted to data (Equation 1).
Y=Gmax/ [1(X/X50)b] where, G is the total germination (%) at concentration x, Gmax is the maximum germination (%), x50 is the osmotic potential required for 50% inhibition of the maximum germination and Grate indicates the slope of the curve in x50. Statistical Analysis System (SAS) was used for analyzing the data.
Results showed temperature, water potential and interaction between them significantly affected germination percentage and germination rate, the time required to reach 5% (D05), 10% (D10), 50% (D50), 90%(D90) and 95% (D95) seed germination of Asian spiderflower. The results showed that by increasing the temperature to 30 °c, seed percentage and germination rate increased and then decreased. Water potential reductions declined seed germination percentage and germination rate. Comparing different models to determine seed germination cardinal temperatures, indicated that the segmented model described germination rate changes to temperature better that the others. Based on the output of this model, germination base, optimum and ceiling temperatures of the plant were 15.46, 33.21 and 39.64 0C, respectively. The result revealed that increasing the PEG concentration, increased the base temperature and decreased optimum and ceiling temperatures. The Logistic model fitted with germination percentage of seeds in different water potentials to different temperatures. Parameters of the model showed the maximum seed germination percentage occurred in the 25 to 35 0C. Highest and lowest X50 parameter (potential required for 50% inhibition of the maximum germination) observed at 30 and 38 0C, respectively. The results showed that the germination ability of Asian spiderflower occurred at less potentials water in the optimum temperature range.
The results showed that high temperatures were required for seed germination of Asian spider flower. Although water potential has reduced the germination of the weed, we can say this is somewhat drought tolerant plants. Based on the segmented model, cardinal temperature for germination, including base, optimum and ceiling temperatures of the plant were 15.46, 33.21 and 39.64 0C, respectively. Check the seed germination, percentage changes in water potentials at different temperatures showed that the desired temperature the plant's ability to withstand in adverse environmental condition increases. Results of this experiment can be concluded that environmental factors affected the germination of Asian spider flower, and this information could help to predict the spread of Asian spider flower in new areas.

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.