مجید آقاعلیخانی

In order to investigate the response of the growth and seed yield of the holy thistle (Cnicus benedictus L.) to the plant density and nitrogen rate, an experiment was conducted in the research farm of the Faculty of Agriculture of Tarbiat Modares University. Experimental treatments were arranged in split plots based on randomized complete block design with three replications. The investigated factors in this experiment included four nitrogen rates (0, 50, 100 and 150 kg. ha-1) as the main factor and four plant densities (100, 150, 200 and 250 thousand plants per hectare) as sub factor. At the time of physiological ripening, fresh and dry weight of stem, leaf, seed yield and yield components and harvest index were determined. The results showed that density × nitrogen interaction effect was significant for all measured quantitative traits except the number of sub-branches per plant and the seed number per plant. Nitrogen fertilizer had a significant effect on the disk number per plant and seed number per disk. In total, the density treatment of 10 plants per square meter caused the highest seed yield and yield components in most nitrogen rates. Based on this, for the seed production of holy thistle in order to develop the cultivated area of this valuable medicinal plant, it is suggested to avoid dense cultivations, which are usually recommended to produce the maximum vegetative body of the plant, because according to the findings of this research, the intensification of inter-species competition in density higher than 10 plants per square meter will cause a significant decrease in seed yield.

In order to study the effect of different sources of nitrogen fertilization on forage and grain yield of three millet cultivars, an experiment was done at Agricultural Research Station of Tarbiat Modarres University during the spring and summer 2019. Experimental treatments were arranged in split plots based in randomized complete blocks design with three replications. In this experiment four nutrition systems including: 100% chemical nitrogen (urea), 100% organic (vermicompost), integrative nutrition-1 (50% vermicompost + 50% urea) and integrative nutrition-2 (50%vermicompost + 50% urea) were located in the main plots and three millet cultivars (Pishahang, KCM2 and Bastan) in sub plots. Different traits such as grain yield, yield components, biomass, harvest index, grain and forage quality indices were investigated. Results indicated to significant effect of nutritional systems on harvest index, thousand grain weight, grain yield and biological yield. Regarding to the means comparison of fertilizer × cultivar interaction the highest grain yield (2830 kg/ ha) and the lowest one (1217.75 kg per hectare) were obtained from the Bastan and KCM2 cultivars respectively. Pishahang and KCM2 cultivar (both common millet) for important traits such as grain and forage yield and quality were in the same statistical group with the superior treatment (urea) under vermicompost and integrated (vermicompost + urea) treatment. While Bastan cultivar (foxtail millet) produced superior grain and forage yield under integrative (nitroxin + urea) treatment. Therefore, using this treatment in small grain millet production, alternating the 50% of chemical nitrogen fertilizer with the biological fertilizer, nitroxin, the acceptable grain and forage yield will produce and we will one step closer to the goals of sustainable agriculture.

This experiment was conducted to investigate the effect of applying different levels of vermicompost and nitrogen fertilizer and their combination on seed yield, seed protein, oil content, and fatty acids profile of the Blessed thistle. The experiment was arranged as a complete block design with three replications in 2018 and 2019 in the experimental field of the faculty of agriculture of Tarbiat Modares University, Tehran, Iran. Treatments consisted of (control (no fertilizer), 100% nitrogen fertilizer requirement, 75% nitrogen fertilizer requirement + 25% vermicompost, 50% nitrogen fertilizer requirement + 50% vermicompost, 25% nitrogen fertilizer requirement + 75% vermicompost and 100% vermicompost). The results showed that the highest biomass (10.32 ton ha-1) and plant height (100.2 cm) was obtained in the combination of 50% nitrogen requirement and vermicompost. The highest 1,000-seed weight (30.9 g), seed yield (1708.3 kg/ha), seed oil percentage (18.9%), and oil yield (323.52 kg/ha) were observed in 100% vermicompost treatment. The highest percentage of linoleic acid (66.7) and oleic acid (25.8) were observed respectively in the treatment of 100% vermicompost and 100% nitrogen fertilizer requirement, and the lowest in the treatment of 100% nitrogen (61.01% linoleic acid) and without Fertilizer consumption (control) (23.09% oleic acid). The results indicated that the vermicompost fertilizer treatments had a positive effect on the quantity and fatty acid composition of the blessed thistle seeds, the treatment required 50% nitrogen fertilizer + 50% vermicompost and for seed production, 100% vermicompost treatment is more suitable in the climatic conditions of the experimental site.

In order to study the effect of nitrogen rate and cutting numbers on forage quantitative and qualitative characters of field amaranth (Amaranthus hypocondriacus L.) a field experiment was conducted at Tarbiat Modares University, Iran, on 2019 growing season. Nitrogen fertilizer was applied in five rates (0, 100, 200, 300 and 400 kg.ha-1) and cutting has two strategies: single harvest (at the beginning of grain filling) and double-cutting (at the beginning of flowering and the beginning of the grain filling). Forage yield and qualitative traits (crude protein, acid detergent fiber, crude fiber and cell wall) were measured at both cutting strategy. The results showed that nitrogen rate had significant effect on quantitative traits and crude protein, and also the effect of cutting on all traits was significant except for LAI and cell wall. Cutting×nitrogen interaction was not significant for any traits, except for dry leaf/stem ratio. Mean comparison showed that 200 kg.ha-1 nitrogen treatment and single-cutting harvest had the highest dry forage yield of 27490 and 27120 kg.ha-1, respectively. Although the highest crude protein percentage was obtained in 400 kg.N.ha-1 treatment and were in same statistical group with 200 kg N.ha-1. Also two- cutting harvest with 15% crude protein was better than single-cutting harvest.

Weeds compete with crop for growth resources and more competitive species will receive more resources.

In order to investigate the effect of tribenuron methyl on growth, physiological and biochemical characteristics of two forage corn cultivars and characteristics of field weeds, a factorial experiment was conducted in a randomized complete block design with three replications at the Research Farm, Faculty of Agriculture, Tarbiat Modares University in 2017. The factors consisted of four doses of tribenuron methyl in soil (0, 20, 40 and 60 g ha-1) and two corn cultivars (N.S 640 and SC 704). Each block included 10 plots and each plot consisted of eight rows and one row without plant between plots. To evaluate the characteristics of weeds, a weed free (hand weeding) plot (alone corn), and a plot without corn were also considered in each replication.

The results showed that over time, weed leaf area index increased and total weed density increased until the middle of the growth period and then decreased. Common purslane (Portulaca oleracea) and red-root pigweed (Amaranthus retroflexus) were the dominant weeds in the fields. The main effect of cultivar and interaction between herbicide concentration and cultivar was not significant in all traits and only the main effect of herbicide concentration was significant.

In general, the results showed that in all forage corn cultivars, the use of 60 g tribenuron methyl ha-1 caused better weed control and reduced competition, increased chlorophyll content, pigment activity and plant photosynthetic rate,

Effect of potassium-silicate, calcium chloride and nano-silicate spray was investigated on yield, yield components and some physiological properties of sweet corn under irrigation regimes in a split plot experiment based on a complete block design with three replications in 2017. Experimental treatments were irrigation regimes as optimal irrigation, moderate and severe water deficit stresses, irrigation after 35%, 55% and 75% depletion of available water in the root zone as the main factor and foliar applications of 1000 and 2000 ppm potassium silicate and calcium chloride , 1000 ppm  nano-silica, pure water and without foliar application as sub plots. The highest grain (6588 kg ha-1), biomass (36050 kg ha-1) and dry forage (30417 kg ha-1) yields were obtained from the main effect of foliar application of 1000 ppm potassium silicate. In water deficit conditions, application of potassium silicate significantly increased grain yield, so that potassium silicate in optimal irrigation conditions, moderate and severe irrigation increased grain yield 7, 25 and 49% compared to non-foliar application, respectively. In intensive irrigation regime the conditions, these increases were -9.29 and 9.82%, for calcium chloride and nano-silica, compared to the control (without foliar). Therefore, according to the results of this study, it can be stated that foliar application of potassium silicate was more efficient in deficit irrigation conditions in sweet corn.

The current study assessed the effects of common herbicides produced by different companies on broadleaved and grass weed control and quantitative traits of irrigated wheat. A two-year experiment (2013-2014 and 2014-2015) was designed as an RCBD with three replications. Experimental treatments included two control treatments (weedy and weed-free) and 15 herbicides produced by three Iranian companies (Ghazal, Golsam-Gorgan, and Gyah) and three international companies (BASF, Nufarm, and Syngenta). The results showed that H13 (bromoxynil + MCPA from BASF tank-mixed with clodinafop propargyl from Golsam Gorgan) and H14 (bromoxynil + MCPA from BASF tank mixed with clodinafop propargyl from Ghazal) treatments in 2014 and H5 (tribenuron methyl from Gyah) and H9 (clodinafop propargyl tank-mixed with tribenuron methyl from Golsam Gorgan) in 2015 almost completely controlled broadleaved and grass weeds. In 2014, H4 (2,4-D + MCPA from Nufarm) and H13 treatments with the averages of 7505 and 7338 kg ha-1 ranked first and second in grain yield, while H9 and H12 (bromoxynil + MCPA from BASF tank-mixed with clodinafop propargyl from Gyah) with the averages of 7966 and 7917 kg ha-1 were known as superior treatments in 2015. Averaged by years, the grain yield was 3185 kg ha-1 at weedy treatment (H17). Although there were no significant differences between herbicides, the grain yield (averaged by years and herbicides) was boosted by 88% compared with the weedy treatment. It was concluded that more rainfall and desirable air temperature positively affected the efficacy of the herbicides.

Sweet corn, Zea mays Var. Saccharata is the youngest form of corn that arose after an accidental mutation in the common corn, and the Native Americans and Indian tribes began to cultivate it after becoming aware of the differences. The first registered variety of sweet corn was named Black Iroquois by European settlers in 1779. In the 19th century, white OP (open pollination) cultivars became popular in the United States. Two varieties of this type that are still cultivated and consumed are the Country Gentleman variety (with elongated and small seeds and irregular rows, also called Shoepeg corn) and the 'Stowell's Evergreen' variety. Scientific developments in the field of plant breeding, including the hybridization technology by inducing traits such as ripening at the same time and improving the quality of cobs and resistance to diseases, created tremendous changes in the production of sweet corn in the 20th century. This article with an overview of the successes achieved in creating new cultivars and improving the quality and marketability traits of sweet corn, its genetic differences from common corn, and the role of hybridization as one of the common tools of classical breeding to achieve superior genotype qualities are emphasized in sweet corn. Classification of sweet corn hybrid cultivars based on factors such as genes affecting carbohydrate metabolism and endosperm sugar percentage, planting time until harvest, seed color (yellow, white, pink, purple, and black), cob shape, and type of consumption (freshly eaten, Freezing, canning and exporting) forms another part of this article. Examining sweet corn breeding methods shows that despite the use of a number of specific techniques and theories, due to the different results of each method, the effect of external pollination, and the high perishability of the final product, Sweet corn breeding is very different in practice. The most important methods in sweet corn breeding have been reviewed in another part of this article. These methods include pedigree breeding, production of synthetic and composite masses, backcrossing and breeding with the help of molecular markers, as well as selection for some special traits such as edible quality, seed production, improved germination in Sh2 seeds, and resistance to pests and pathogens. In the final part, all kinds of sweet corn varieties, including commercial hybrids for fresh consumption and hybrids suitable for processing, have been introduced according to the genetic changes that have taken place in sweet corn cultivars since long ago.

Application of medicinal plants ecotypes from natural habitats in agronomic and genetic research requires field and laboratory investigations to select the best chemotypes. The present study was conducted to investigate the effect of habitat altitude on the amount of essential oil and active ingredient of German chamomile (Matricaria chamomilla L.) in Bushehr province. The chamomile population of natural habitats in three altitude ranges, zero -100, 100-350 and 350-750 meters above sea level with four replications (regions) investigated in a randomized complete blocks design. In all 12 studied habitats, in addition to harvesting plant samples in the full flowering stage, soil samples were also examined. The yield of essential oil of dried flowers was determined according to the herbal pharmacopoeia of Iran by water distillation method. The amount of Chamazulen in the alcoholic essential oil was measured through spectrophotometry, and the amount of Apigenine 7-glucoside was measured according to American Pharmacopoeia (USP-20) through HPLC. The results showed that the difference in altitude of the habitat did not make a significant difference in amount of essential oil and effective substance of chamomile. Despite this, the highest amount of essential oil (0.742%) was found in flowers grown at higher altitudes, and the ecotypes grown in lower areas had more secondary metabolites (4.25% Chamazulene and 0.50% Apigenin 7-glucoside). Therefore, it can be stated that the maximum production of essential oil depends on the soil fertility, and to obtain more effective substances, it is recommended to collect chamomile seeds from the lower habitats.

The phenomenon of seed dormancy in weeds not only lead to management difficulties over time but also can disrupt the biological, morphological and ecological studies carried out on these species. This study was conducted to investigate the effect of ultrasound on seed dormancy breaking of Datura stramonium and Convolvulus arvensis in laboratory conditions. Two separate experiments were conducted as a completely randomized design with four replications for each species. The ultrasonic waves were applied at five powers including 0, 80, 150, 250 and 350 watts for four and eight minutes, where the applied ultrasonic frequency was 20 kHz and the temperature of water was remained constant at 25°C. In addition to the ultrasound treatments, the common dormancy-breaking treatments including chilling (natural chilling, moist chilling and dry chilling) and mechanical scarification were applied on D. stramonium and C. arvensis, respectively. All sonication treatments decreased accumulated maximum germination (Gmax) of both weed species. Also, the ultrasound treatments increased time to 50% of maximum germination (G50) of D. stramonium. The ultrasonic effect on G50 of C. arvensis was depended on ultrasonic power, where at low ultrasound powers the G50 of D. stramonium was similar to untreated seeds, while it was decreased at high ultrasound powers. Accordingly, ultrasound was not a suitable method to break seed dormancy of D. stramonium and C. arvensis. As the best treatments, the natural chilling and mechanical scarification increased Gmax of D. stramonium and C. arvensis up to 49% and 38%, respectively.

Oxidation of vegetable oils is a major challenge in the food industry. Canola oil is prone to oxidation because of high unsaturated fatty acids. An effective way to prevent oxidation of oils and fats is addition of antioxidants. However using synthetic antioxidant due to the possibility of toxic and carcinogenic effects is limited. Thus, todays essential oils from aromatic plants have been qualified as natural antioxidants and proposed as potential substitutes of synthetic antioxidants in food products. Marigold (Calendula officinalis L.) from Asteraceae family with significant applications in food and pharmaceutical industries. The main objective of this study was to identifythe chemical composition of flowers essential oil and comparison of antioxidant effects of marigold essential oil with butyl hydroxytoluene in canola oil stability.

This experimental study was conducted in 2019 at Nahavand University. Flowers essential oil was extracted by hydro-distillation technique using clevenger apparatus. The oil was analyzed by capillary GC and GC/MS. The total phenolic content of the essential oil was measured by Folin-ciocalteau method. Antioxidant activity of essential oil was assessed by using diphenyl picrylhydrazyl (DPPH) method and β-carotene/linoleic acid system and compared with synthetic antioxidant butylated hydroxy toluene (BHT). Then the effect of marigold essential oil was added to the non containing antioxidant canola oil at four concentrations (100, 200, 400 and 800 ppm) to determine antioxidant activity. Also an oil sample without antioxidant and two oil samples containing 100 and 200 ppm BHT were prepared.The oils were kept at 60 °C for 35 days and peroxide, thiobarbitoric acid, acid and carbonyl values were measured every 7 day. Experimental data were analyzed using ANOVA by the SPSS version 20 software and mean comparison were done using Duncanchr(chr('39')39chr('39'))s multiple range test.

The major components of flower essential oil were -cadinol (49.52%), -cadinene (15.35%) and Δ-cadinene (8.36%), respectively. The concentration of phenolic compounds in the essential oil was determined and found to be 32.74±0.63 mg as gallic acid per gram of essential oil. The half maximal inhibitory concentration (IC50) of marigold essential oil was 10.36±0.21 μg/ml, while this parameter for BHT 9.14±0.19 μg/ml. Flower essential oil of marigold at the concentration of 800 ppm had better antioxidant activity than the other essential oil concentrations. In addition, it was shown that antioxidant activity was directly correlated with the increase of the essential oil concentration. In the study of antioxidant properties of different concentrations of flower essential oil in canola oil showed that the highest antioxidant activity belonged to the oil sample contained 800 ppm of essential oil, which did not show significant difference with BHT at concentration 100 ppm (p> 0.05).

Marigold essential oil at the concentration of 800 ppm has antioxidant acivity in canola oil, it can be concluded that this plant can be a suitable natural antioxidant as an alternative to synthetic antioxidants in the oil industry.

There is ample evidence to illustrate the role of triazoles and silicon in mitigating the effects of abiotic stresses. However, the potential of nano-silicon and tebuconazole and their possible interactions in ameliorating the effects of drought stress and related mechanisms in sugar beet have not been investigated so far. Therefore, a split-plot factorial experiment based on randomized complete block design with four replications was carried out at Motahari Research Station of Sugar Beet Seed Institute (SBSI), Karaj, Iran over two seasons, 2016 and 2017. Three irrigation treatments including 100, 75, and 50% of plant evapotranspiration (normal, mild stress, and severe stress, respectively) were assigned to the main plots. Subplots were composed of a factorial combination of three nano-silicon doses of 0, 1 and 2 mM and two tebuconazole doses of 0 and 25 mg l-1. The results showed that under severe drought stress, the effect of nano-silicon on the studied traits was dose-dependent, so that the application of nano-silicon with 1mM concentration improved growth parameters as well as physiological traits and increased white sugar yield and the maximum dry matter by 20 % and 17%, respectively compared with severe drought stress treatment. Under severe drought stress condition (irrigation at 50% of plant evapotranspiration), the highest leaf area index, chlorophyll and relative water content were observed in 1 mM nano-silicon treatment. Under severe drought stress, foliar application of 2 mM nano silicon had an adverse effect on sugar yield. The combined application of nano-silicon and tebuconazole improved dry matter production and sugar yield by maintaining plant greenness and preventing leaf aging which may indicate an interaction between these two compounds. These results indicate that nano-silicon and tebuconazole can be used as a suitable tool to mitigate the effects of drought stress on sugar beet.

To investigate the effect of delayed sowing on seed and oil yields of rapeseed (Brassica napus L.) genotypes, a field experiment was carried out at the research field station of Seed and Plant Improvement Institute, Karaj, Iran in 2015-2016 and 2016-2017 cropping seasons. The experimental design was split plot arrangements in randomized complete block design with three replications. Optimal sowing dates (02 October) and delayed sowing date (01 November) were assigned to the main plots, and 17 rapeseed genotypes [French (eight), Iranian (five), Hungarian (two) and German (two)] were randomized in sub-plots. Combined analysis of variance showed that all main and interactions effects were significant on all studied traits (except the main effect of year on seed oil content). Plant developmental stages experienced different environmental conditions due to delayed sowing and led to decreases in seed yield and yield components, seed oil yield and biological yield. The highest seed yield in optimal sowing date belonged to Garou (in the first year) and HL2012 (in the second year) genotypes with an average of 5240 and 5805 kg ha-1, respectively. However, Okapi (in the first year) and Garou (in the second year) had the lowest seed yield in delayed sowing date with an average of 3624 and 2702 kg ha-1, respectively. Lauren (in the first year) and Darko genotypes (in the second year) had the lowest grain yield reduction (%) in delayed sowing date which accounted for 21.5% and 35.9%, respectively.

To evaluate the effect of different nutrition systems (such as organic, chemical and biologic) on quantitative and qualitative traits of three selected lines of grasspea (Lathyrus sativus L.), a field experiment was conducted at College of Agriculture, Tarbiat Modares University during 2012-2013 growing season. The Experimental treatments were arranged as factorial layout based on a randomized complete block design with three replications. The first factor was three grasspea lines (L1 (Sel.B/222), L2 (Sel.B/111) and L3 (Sel.290)) and the second factor was four nutrition system (no fertilizer (F0), 100% chemical fertilizer (F1), 100% manure (F2) and integrated fertilizer (75% manure + 25% Nitroxin (F3)), respectively. Results showed that L1 (Sel.B/222) receiving 100% chemical fertilizer produced maximum forage yield (20145.8 kg.ha-1), whereas the integrated nutrition system (75% manure + 25% Nitroxin) produced the highest dry forage yield (3005.3 kg.ha-1). Integrated nutrition system (75% manure + 25% Nitroxin) having the highest percentage of dry matter digestibility, the highest protein percentage and the lowest ADF was the superior treatment in forage quality. L1 (Sel.B/222) grasspea treatment was superior in maximizing the percentage of dry matter digestibility and minimizing the percentage of ADF. The grasspea line L3 (Sel.290) produced the highest percentage of protein. The lowest crude fiber content of grasspea forage was achieved in L3 (Sel.290) under integrated nutritional system. Thus, the combined system of L1 (Sel.B/222) and F3 (75% manure + 25% Nitroxin) is a good alternative or chemical fertilizers and could be suggested for qualified and higher forage yield of grasspea.

Summer savory (Satureja hortensis L.) is an aromatic plant, belonging to Lamiaceae family. The essential oil of this plant is used in medicinal and food industries. The essential oil of summer savory has antioxidant, anti-inflammatory and analgesic properties. The main objective of this study was to identify the chemical composition of aerial parts and evaluate the antioxidant and antimicrobial activities of summer savory essential oil against a few microorganisms including gram positive, gram negative bacteria, filamentous fungi and yeast.

In this experimental study, shoot essential oil was extracted by hydro-distillation technique using clevenger apparatus. The oil was analyzed by capillary GC and GC/MS. Antioxidant activity of essential oil was assessed by diphenyl picrylhydrazyl radical-scavenging activity and compared with synthetic antioxidant Butylated Hydroxyl Toluene (BHT). Antimicrobial properties of the plant essential oil were determined using micro broth dilution and well disk diffusion methods.

The major components of essential oil were carvacrol (42.10%), thymol (19.74%) and P-cymene (8.19%), respectively. The half maximal inhibitory concentration (IC50) of summer savory essential oil was 10.63±0.15 μg/ml, while this parameter for BHT 9.45±0.09 μg/ml. Bioassay of essential oil showed that summer savory had strong antimicrobial effects. So that, aerial part essential oil showed the best antifungal activity and this effect is more than the antibacterial activity. The mean diameter of inhibitory growth zone in well disk diffusion method at 15 µl concentration was equal to 31.05±0.57 mm in the case of gram positive bacteria, 21.68±0.40 mm for gram negative ones and 42.76±0.33 mm in the case of filamentous fungi and yeast. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of summer savory essential oil ranged from 0.5 to 16 µl/ml in the case of all microorganisms.

It can be stated that summer savory essential oil on all of yeast and filamentous fungi, gram positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis) and gram negative bacteria (Shigella flexneri, Serratia marcescens, Escherichia coli and Klebsiella pneumonia) showed more antimicrobial activity than amphotericin B, vancomycin and gentamicin, respectively. Although more research is needed in this field, summer savory essential oil can be used as a new antimicrobial agent in the pharmaceutical and food industries.

In order to investigate some characteristics of three sweet maize varieties under application of various fertilizers and water deficit stress at the reproductive stage, a field experiment was conducted in Tarbiat Modares University during the 2016 growing season. The experiment was performed at three replications with the Factorial Split Plate arrangement in a completely randomized block design. Factors of irrigation regimes as irrigation after discharging 25, 40 and 55% of water used and cultivars (Basin, Passion and KSC403) in the main plot and fertilization included urea (116 kg.ha-1), azocompost (15497 kg.ha-1) and vermicompost (24223 kg.ha-1) in the subplot were studied. The results showed that the highest ear fresh weight (236.77 g.m-2) was observed in optimum irrigation conditions. Grain yield was significantly affected only by fertilization (p≤0.05). The application of urea fertilizer increased grain yield, while the use of azocompost decreased it. The highest and lowest ear fresh weight were obtained in Passion and KSC403 cultivars, respectively. Passion cultivar in severe water stress and Basin cultivar in moderate water stress and optimum irrigation was produced the highest ear fresh weight and KSCO403 cultivar showed the lowest amount in all irrigation regimes. The highest amounts of chlorophyll a and b were obtained with 1.74 and 0.47 mg.g-1 fresh weight, respectively, from optimal irrigation. Vermicompost (only 4% decrease compared to control) and urea, (about 13% more than control) respectively, under sever water stress and moderate water stress conditions, somewhat controlled the effect of water shortage in Passion cultivar and increased the ear fresh weight.

Fitness costs of herbicide resistance may be more evident and increase under stress environmental conditions. To test this hypothesis, a herbicide-resistant (R) and a herbicide-susceptible (S) phenotype with controlled and homogenized genetic background were isolated within a non–target-site resistant (NTSR) black-grass population. Accumulated maximum germination (Gmax) and time to reach the Gmax (G50) of biotypes were examined under non- and abiotic-stress conditions (salinity at 16 dSm-1, drought at -0.8 Mpa). In addition, seedling pre-emergence growth of the biotypes were evaluated at non-stress condition. There was no difference in Gmax between the R and S biotypes, whereas the Gmax of R phenotype was 28% and 49% lower than that of the S phenotype under salinity- and drought-stress conditions, respectively. The R phenotype germinated around seven to 16 hours later than the S phenotype under all non- and abiotic-stress conditions, i.e. the R phenotype had higher G50 than the other phenotype. The experiments of seedling pre-emergence growth showed that the R and S biotypes had similar root and shoot length under non-stress condition. The results clearly showed that the germinability fitness costs of NTSR black-grass increase when the plants are grown under salinity- and drought- stress conditions.

To investigate the effect of planting density on quantitative and qualitative characteristics of globe artichoke (Cynara cardunculus L. var. Scolymus (L.) Fiori) under weedy and weed-free conditions, a field experiment was conducted at Tarbiat Modares University, Tehran in 2016 growing season. A factorial arrangement of the experimental treatments was studied in a randomized complete block design with three replications. The factors included four crop planting densities (2, 4, 6 and 8 plants m-2) under two conditions of presence and absence of weeds. Different traits including leaf number per plant, leaf area index, total dry weight, chlorophylls a, b and total chlorophyll, caffeic acid, chlorogenic acid and total polyphenol contents were measured. The results showed that leaf number and dry weight were significantly affected by plant density and weed competition in artichoke, so that the weed competition reduced the artichoke dry weight by 22.4%. The highest leaf area index (2.29) and dry weight of artichoke (253.44 g m-2) were observed at 6 plants m-2, while the highest number of leaves per plant (16.33) belonged to the density of 2 plants m-2. Among qualitative traits chlorophylls a, b and total chlorophyll were only affected by weed presence while caffeic acid, chlorogenic acid and total polyphenol contents were only affected by plant density. The effect of crop plant density on weed leaf area and dry weight was also significant. Overall, the highest performance of the main secondary metabolites in artichoke including caffeic acid, chlorogenic acid and total polyphenol (5.99, 9.55 and 5.89 g m-2, respectively) were obtained at 6 plants m-2, completely affected by crop dry matter yield.

To evaluate the growth duration and seed yield of two different Guar ecotypes in response to planting time and plant density, a field experiment was conducted in 2016 growing season at the research field of Tarbiat Modares University, Iran. Experimantal factors were arranged as split plot-factorial in a randomized complete block design with three replications. The experimental factors included four planting dates (21 May, 4 June, 21 June and 5 July) assigned to main plots, and factorial combination of three plant densities (130, 200 and 400 thousand plants.ha-1) and two Guar ecotypes (Pakistani and Indian) as sub-plots. The results showed that maximum seed yield (3004.8 kg.ha-1) was obtained from 21 May sowing date and plant density of 130 thousand plants ha-1, while in 4 June sowing date, the highest seed yield was harvested from plant density of 200 thousand plants.ha-1 (1834.4 kg.ha-1). There was significant difference for grain yiled between ecotypes in 21 May and 5 June sowing dates. Pakistani ecotype produced highest highest seed yield (2706.1 kg.ha-1) in 21 May sowing date. In the second sowing date (4 June), the Pakistani ecotype produced 32.1% grain yield more than the Indian ecotype. Pakistani ecotype was superior for seed endosperm percentage (40.5%) as compared to the Indian ecotype (38.8%). In conclusion, sowing of Pakistani ecotype on 21 May with plant density of 130 thousand plants.ha-1 had higher seed yield, longer growing duration, taller plant height, higher 1000-seed weight, higher pod number per square meter, dry matter and harvest index. Therefore, it could be suitable for climatic conditions similar to Karaj in Iran.

In order to investigate the effect of late-season drought stress on some physiological traits, yield and yield attributes, a two-year field trial was carried out at the research field of Seed and Plant Improvement Institute, Karaj, Iran, on 2015-2017 growing seasons. Factorial arrangement of the treatments was set up as randomized complete block design with three replications. Experimental factors consisted of irrigation regimes (normal irrigation and withholding irrigation from silique setting stage until the end of the growing season) and 17 new winter genotypes of rapeseed. Several physiological traits included relative water content (RWC), total chlorophyll, proline as well as grain yield and yield attributes as dependent variables were measured. Results showed that amount of total chlorophyll under withholding irrigation was reduced (21.65 percentage) reduced compared to the normal irrigation, while leaf proline content was increased by 28.04 %. According to the findings of this study, superior genotypes were not necessarily top in terms of proline. Averaged over both years, Artist genotype produced highest grain yield (5043.25 kg.ha-1) under normal irrigation condition, while L72 and HL3721 had highest grain yield (3915.25 and 3892.45 kg.ha-1, respectively) under withholding condition. It is worth noting that this advantage was mainly revealed to increased source capacity (number of silique plant-1, silique length and number of seed silique-1) as well as the superiority of chlorophyll content and relative water content of the leaf.

In order to evaluate the intercropping of Sweet corn and Okra affected by vermicompost and ‎urea fertilizer a field experiment was conducted at research field of Tarbiat Modares ‎University during 2015 spring and summer. In this research effect of‏ ‏five mixing ratio‏ ‏of ‎sweet corn/okra including: 100:0 (sweet corn monoculture), 75:25, 50:50, 25:75 and 0:100 ‎‎(okra monoculture) and two nutrition systems consisted of chemical (urea) and organic ‎‎(vermicompost) were investigated with factorial arrangement of treatments based on ‎randomized complete block design with three replications. The results showed that factors ‎interaction on the number of desirable ear, sweet corn yield and okra seed yield were ‎significant (P≤ 0.01). Also mixing ratio effect on sweet corn 100 kernel weight (P≤ 0.05), okra ‎‎1000 kernel weight and the number of fruits square meter (P≤ 0.01) was significant. ‎According to mean comparisons the highest sweet corn yields (9614.58 kg.ha-1) and okra ‎‎(2848.65 kg.ha-1) was obtained in their monoculture receiving the chemical fertilizer. The ‎highest LER‏ ‏‎(2.10) was obtained in 50:50 treatment under vermicompost nutrition system ‎followed by 75:25 under same nutrition system (LER=1.93). Also competition index ‎evaluation in the different treatment confirmed the rating of superior treatments.‎

Weed control in crop lands using herbicide raised several concerns for human health and environment. Decomposition of some plants residues leave special compounds in the soil which may prevent weed emergence and prohibit the use of herbicides for weed control. In order to non-chemical weed management and investigation of the sweet corn response to wheat and rye residues (low, medium and high) a field experiment was conducted using RCBD. Results showed that wheat straw was more beneficent than rye in weed control and increasing the sweet corn yield, meanwhile wheat in low residue treatment was more effective than others. Indeed this treatment produced the highest leaf area index (7) and fresh forage yield of the crop (24693 kg.ha-1). The highest (2251.3 kg/ha) and the lowest (1653.8 kg/ha) amount of kernel yield were obtained under low wheat residue and low rye residue treatments respectively with +22% and -6.2% change from control treatment. Therefore it should be stated that sweet corn planting after wheat rotation will confront to less weed (density and biomass) due to allopathic effects of low wheat residue which indirectly increased sweet corn economical yield.

Water deficit stress is one of the most important environmental stresses which affect the crop production. Genetic improvement or application of drought tolerant genotypes is recommended to increase crop production under water restricted conditions. The objective of the current study is investigating the withholding irrigation effect in terminal stages of the growing season on agronomic performance of rapeseed new genotypes in a semi-arid climate. The experiment was conducted during 2015-2016 growing season in Karaj, Iran. Experimental factors (two water irrigation regimes and 17 rapeseed genotypes) were investigated with factorial arrangement of treatments based on a randomized complete block design (RCBD) with three replications. In this study, several different traits including plant height, number of siliqueper plant, number of grain per silique, 1000-grain weight, grain yield, biomass, oil percentage and oil yield were measured. To determine the most tolerant genotypes, stress tolerance indices (SSI, TOL, STI and GMP) were calculated under stress (withholding irrigation from silique setting stage until the end of the growing season) and non-stress (normal irrigation) conditions. Also, agronomic water use efficiency (WUEagr) was calculated for both irrigation conditions. Mean comparison of the interaction between withholding irrigation and genotypes showed that the responses of genotypes were different in terms of plant height, number of siliqueper plant, number of grain per silique, 1000-grain weight, grain yield, biomass, and oil yield at irrigation different treatments. Finally under withholding irrigation treatment from silique setting stage until the end of the growing season, Lauren hybrid was identified as the superior genotype due to suitable agronomic traits such as plant height (158.9 cm), number of siliqueper plant (158.6), number of grain per silique(18.6), 1000-grain weight (3.44 g), biomass (15471 kg.ha-1), grain yield (3854.3 kg.ha-1), oil percentage (43.33%) and oil yield (1668.3 kg.ha-1). Based on the stress tolerance indices among 17 rapeseed genotypes, the most tolerant genotypes were Lauren, Zorica, Alonso and Zlanta. Finally with considering to WUEagr (Kg.ha-1.mm-1), Zorica (0.92), Artist and Lauren genotypes (0.88) had the highest WUEagr under normal irrigation conditions, while Alonso (0.86), Lauren (0.84) and KL3721 (0.82) had the highest WUEagr under withholding irrigation conditions. Generally in this study, the amount of the studied traits was decreased under conditions of withholding irrigation compared to the full irrigation. Yield components such as silique number per plant, grain number per silique and 1000-grain weight could be considered as key traits affecting rapeseed grain yield under withholding irrigation.