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• Polyphenol, Caffeic and chlorogenic yield were increased by plant density. • Drought resulted in a decrease in polyphenol, caffeic and chlorogenic yields. • Caffeic and chlorogenic yields were completely influenced by dry matter yield. To study the effects of water stress and plant density on the qualitative and quantitative characteristics of artichoke (Cynara cardunculus var. scolymus), a two-year field experiment was carried out in a semi-arid region in 2016 and 2017. The experimental treatments were arranged as split-plot in a randomized complete block design with three replications. The main plots were three irrigation treatments of 40, 60 and 80% field capacity and sub-plots consisted of four planting densities of 2, 4, 6 and 8 plant m−2. The results showed leaf area, dry matter, and chlorophyll (a, b, and total) concentration decreased by water deficit stress, whereas proline concentration was increased by water deficit stress. Dry matter and LAI were significantly affected by plant density, so that the highest dry matter and LAI in all irrigation treatments were observed at the populations of 6 plants m−2. An increase of plant density decreased concentrations of chlorophyll a and b and total chlorophyll in artichoke leaves. The various irrigation treatments and plant densities influenced total polyphenol and yields of caffeic and chlorogenic acids. Among irrigation treatments, the highest yield of caffeic acid, chlorogenic acid and total polyphenol (5.14, 8.24, and 5.01 g m−2, respectively) belonged to the non-stressed control. In addition, the highest yield of caffeic acid, chlorogenic acids and total polyphenol (5.90, 9.38, and 5.60 g m−2, respectively) were observed at the population of 6 plants m−2. For both of these factors, the yields of these compounds were completely affected by dry matter yield. [ABSTRACT FROM AUTHOR]

Aerial parts of blessed thistle ( Cnicus benedictus L.) contain high amounts of phytochemicals and would be improved through varying agronomic management practices such as N rate and plant density. The objective of this study was to investigate the effect of different N fertilizer rates and plant densities on agronomic performance, photosynthetic capacity, leaf area index, carbon to N ratio (C/N), cnicin content, total phenol and flavonoids, and antioxidant activity in blessed thistle. A two-year field experiment was conducted in a semi-arid region in Iran in 2013 and 2014. The experiment was arranged as a randomized complete block design with a factorial arrangement and three replicates. Treatments consisted of four N rates (0, 50, 100 and 150 kg N ha −1 ) combined with five plant densities (5, 10, 15, 20 and 25 plants m -2 ). Total chlorophyll and straw N contents as well as photosynthesis rate significantly increased by either 50 or 100 kg N ha −1 . The significant reductions of straw N in 2013 and photosynthesis rate in both years were found with increasing plant density. Total phenol, flavonoid contents, C/N ratio and antioxidant activity were decreased as a result of increased N rate. The highest cnicin contents and yields were obtained from high plant densities under low N rates. This response may be attributed to N and plant density compensation effect. The enhancement in secondary metabolites and antioxidant activity were associated with high C/N ratio and low N contents, and accompanied by a decrease in chlorophyll content that showed a positive correlation with photosynthesis and biomass yield. The study demonstrates that increasing plant density (>15 plants m −2 ) with a low N rate (50 kg N ha −1 ) could be suitable for both biomass and phythochemichal production of blessed thistle. Furthermore, this study suggests that blessed thistle has the ability to achieve higher biomass and yield of cnicin in poor soils and unfavorable conditions. [ABSTRACT FROM AUTHOR]

The Iranian energy sector has recently discovered a great interest in the concept of renewable and clean energy. The interest is motivated primarily by concerns about greenhouse gas (GHG) emissions and global climate change, as well as the desire to find alternative and sustainable energy sources and create potential job opportunities related to these new technologies for future generations of Iranians. This study supports the search for alternative, sustainable energy sources by assessing okra's usability as a biofuel. Okra is an annual, warm season crop that provides a rich source of industrial oil and protein. According to our investigation, the seeds of Iranian okra ecotypes that have an oil content of 20% could produce up to 325 kg/ha oil yield. Our study on Iranian okra seed oil showed that, the most dominant fatty acids of are linoleic acid (C18:2) (38–40%), Palmitic acid (C16:0) (29–30%), and Oleic acid (C18:1) (19–22%). The biodiesel derived from okra via a transesterification reaction using an ultrasonic system could meet ASTM D6751 standards with satisfactory results in methyl ester content (more than 96%), viscosity (2.3–2.4 mm −2 /S, and flash point (155–158 °C)). Because of its high oil yield, quality, and large ecological adaptation window, okra is a strong contender to provide a new source of non-edible oil for biodiesel production in bioenergy farms. [ABSTRACT FROM AUTHOR]

Highlights: [•] Weeds can be a friend of the agroecosystem rather than a foe. [•] First report of corn–pigweed mixture response to different water regimes and N rates. [•] The corn–pigweed mixture was superior to the corn in terms of input use efficiency. [•] The N leaching intensity decreased in the presence of weeds and in response to N. [•] Corn and weed cooperation to produce high quantity and quality forage. [Copyright &y& Elsevier]

• Water deficit stress mitigated by synergistic effect of boron and epibrasinolid. • Boron and 24-epibrasinolid spray improved the oil %. • Polyunsaturated fatty acid content improved by foliar spray. The high oil content and quality of camelina [ Camelina sativa (L.) Crantz] seed oil for various uses, including human nutrition and industry, has encouraged many countries to increase the cultivation of this oilseed crop. Due to the coincidence of initial irrigations of summer crops with the final stages of camelina growth, production of this crop in arid and semi-arid regions depends on tolerance to the late-season water deficit stress. Therefore this two years field experiment focused on boron (B) and 24-epibrassinolide (EBL) foliar spray effect on seed yield, oil content, oil yield and fatty acids profile (FAs) of camelina in a semi-arid area (Iran) during 2018−19 and 2019−20 growing season. Experimental treatments were arranged in a split-plot design based on randomized complete blocks with three replicates. Irrigation regimes based on withholding irrigation (WI): [full irrigation (FI) at 50 % of available soil water (ASW); withholding irrigation with 20 % of ASW from full flowering to silicle formation (WI 1); withholding irrigation with 20 % of ASW from silicle formation to harvesting (WI 2)] were considered as the main plots and ten levels of foliar spray (FS) consisted of control (non foliar spray), distilled water, B (0.5 and 1%) and EBL (0.5 and 1 μM) and their concomitant use (B 0.5 % + EBL 0.5μm , B 0.5 % + EBL 1μm , B 1% + EBL 0.5μm , and B 1% + EBL 1μm) were randomized to the subplot units. Seed and oil yield decreased by 6.7–8.4 % and 10–12 %, respectively in response to the water deficit during the flowering and silicle formation stages. The negative effect of drought stress on the quality of camelina oil was recorded as 3.3–5.3 % increment in erucic acid and significant decrease in the unsaturated fatty acids (UFAs) content, oleic acid (by 4.6–8.5 %), linoleic acid (by 3.5 %), linolenic acid (by 2.5 %) and 1.2–2.8 % for monounsaturated fatty acids (ΣMUFAs) content compared with the control treatment. While foliar spary of B and EBL increased oil content by ranged from 2 to 4% under-withholding irrigation treatments. Also ecosanoic acid and polyunsaturated fatty acids (ΣPUFAs) content significantly increased under combined application of B 0.5 + EBL (0.5 and 1). [ABSTRACT FROM AUTHOR]

Abstract: Descurainia sophia (flixweed) is an annual weed widely distributed in cultivated crops, forage and rangelands throughout the world. This weed, in particular its seed, is used for food, medicinal and industrial purposes. The objective of this study was to investigate the effects of irrigation management and different application rates of nitrogen on morphological traits and yield components of this weed as a means of enhancing production and economic returns. A two-year field experiment was conducted in a semi-arid region in Iran during the 2009–2010 and 2010–2011 growing seasons. The experiment was a split plot in a randomized complete block design with three replicates, with irrigation treatments as main plots and nitrogen rates as sub plots. The three irrigation regimes consisted of 0.1 maximum allowable depletion or deficiency (MAD) of available soil water (ASW), 0.2 MAD of ASW, 0.4 MAD of ASW in 2010 and 0.2 MAD of ASW, 0.4 MAD of ASW and 0.8 MAD of ASW in 2011. The plants were grown at three nitrogen rates of 0, 200, and 300kgNha−1. Generally there were significant increases in seed yield, biomass, straw yield, harvest index, number of siliques (pods) per plant, seed weight, plant height, time to maturity, water use efficiency, protein concentration in seed, straw N concentration, nitrogen uptakes and nitrogen harvest index each growing season by applying nitrogen at all irrigation treatments. There was a decreasing trend in number of plants per m2, nitrogen utilization efficiency and oil concentration with increasing nitrogen application under all the irrigation treatments. Seed yield response to irrigation treatments and N rates seemed to be more related to number of plants per m2 and number of siliques per plant. The highest seed yield was obtained at the plant population of 686plantsperm2. The results obtained here suggest that nitrogen application can improve the seed yield and seed quality of D. sophia grown under different irrigation regimes. Averaged over both years, the application of 300kgNha−1 under 0.2 MAD of ASW resulted in the highest revenue; 200kgNha−1 was not significantly different to 300kgNha−1. [Copyright &y& Elsevier]

Abstract: A cohort-based population model was developed to simulate the population dynamics and management of Bromus diandrus. Model parameters were derived from our experiments and from published sources. Individual and integrated management strategies were simulated. More than 85% of B. diandrus seeds emerged within the first cohort. In the absence of any control the seed-bank population grew until reaching an equilibrium at density of 17,324 seeds m−2. Results pointed to the difficulty in controlling this weed with individual control tactics. All integrated programmes simulated resulted in long-term reductions in the seed bank. Simulations showed that the combination of pre-emergence and post-emergence herbicides or combination of autumn shallow cultivation and post-emergence herbicides are the best techniques to employ in integrated weed management (IWM) programmes in cereal. A sensitivity analysis indicated that B. diandrus is particularly vulnerable to small changes in the fecundity of the first cohort. Consequently, it is important to find strategies which can reduce the effect of the first cohort, because this is a clue to the control of this weed. [Copyright &y& Elsevier]

Abstract: Experiments were conducted in 2006–2007 at six research stations of the Iranian Plant Protection Research Institute to study the efficacy of different herbicides to control weeds in wheat. Treatments included mesosulfuron-methyl plus iodosulfuron-methyl-sodium plus mefenpyr-diethyl (WG) at 45+45+135ga.i./ha, respectively, sulfosulfuron at 21, 31.5, 42 and 51ga.i./ha, chlorsulfuron at 15ga.i./ha, bromoxynil plus MCPA at 600ga.i./ha with clodinafop propargyl at 64ga.i./ha, sulfosulfuron plus metsulfuron-methyl at 36ga.i./ha, mesosulfuron-methyl plus iodosulfuron-methyl-sodium plus mefenpyr-diethyl (OD) at 15+3+45ga.i./ha, respectively, and a full season weed-free control. Herbicides were applied at wheat tillering. Results showed that sulfosulfuron plus metsulfuron-methyl, and bromoxynil plus MCPA with clodinafop propargyl resulted in satisfactory weed control and wheat grain yield at most locations. Weed control efficacy of both formulations of mesosulfuron-methyl plus iodosulfuron-methyl-sodium was variable across locations. Efficacy of the OD formulation appears to depend upon location, so that application of this herbicide at Shiraz and Gorgan resulted in better weed control compared to use of the WG. Satisfactory performance of the OD formulation at Gorgan and Shiraz could be attributed in part to the even pattern of rainfall distribution during the growing season and wheat cultivar used, respectively. With respect to grain yield, however, the OD formulation was better than WG formulation at most of the locations. [ABSTRACT FROM AUTHOR]

Water deficit is the main reason for sugar yield losses in semi-arid areas. Triazole derivatives may mitigate the harmful impacts of water stress. Therefore, this study aimed to assess the effect of tebuconazole (TEB) application on antioxidants, root quality traits, and sugar yield under drought stress conditions. The treatments included three levels of irrigation set according to crop evapotranspiration (ET C): 100%, 75%, and 50% ET C , as well as three levels of TEB (0, 25, and 50 mg L−1). While significantly increasing antioxidant and alpha-amino-nitrogen (α-amino-N) contents, limited irrigation decreased total chlorophyll content, net photosynthesis rate, leaf relative water content, the weight of roots, and sugar yield. In contrast, TEB treatment resulted in a marked rise in all biological and physiological traits as well as enzymatic antioxidants. Our findings indicated that the decline in α-amino-N content might be linked to increased NR activity in response to the TEB application. Our results also showed that the stress-ameliorating role of TEB cannot be associated with the increase of flavonols (quercetin and rutin). Overall, the results demonstrated that TEB has a high potential for ameliorating the negative impacts of limited irrigation. [Display omitted] • TEB-treated plants exhibited an improved activity of antioxidant enzymes under limited irrigation. • The stress-ameliorating role of TEB cannot be associated with the increase of flavonols in TEB-treated plants. • Improved nitrate reductase activity may be responsible for increasing white sugar yield under severe water stress. • Spraying of TEB substantially decreased alpha-amino-N in sugar beet taproot under limited irrigation. [ABSTRACT FROM AUTHOR]

Screening new alternative vegetable oil sources as biodiesel feedstocks has attracted worldwide attention as world oil reserves decline and environmental concerns increase. Blessed thistle (Cnicus benedictus L.) has recently been identified as a multipurpose crop with optimal economic yield in poor soils. Blessed thistle was seeded into three different site soil conditions (site 1: silt clay loam, site 2: sandy loam, site 3: saline sandy loam) in eastern North Dakota, USA to evaluate agronomic performance and seed properties as well as biodiesel potential. The highest biomass and plant heights were obtained from the sandy loam soil, while plants grown in saline sandy loam soil had similar seed and oil yield, and similar oil content as plants grown in other site soil conditions. Biodiesel obtained from blessed thistle oil in the saline site was an excellent substitute for fossil fuels. The saline soil did not influence the blessed thistle oil yield; however, the saline soil did affect the fatty acid composition and biodiesel properties with some improvement in biodiesel quality. Results showed that blessed thistle was a promising species for biodiesel feedstock, especially for marginal soils such as the saline soil conditions in North Dakota. • Site soil conditions caused a slight variation in blessed thistle productivity. • Blessed thistle is a salt-tolerant promising plant to grow in marginal lands. • Blessed thistle is a potential feedstock for biofuels production. • Saline soil induced lipids are suitable for biodiesel production. [ABSTRACT FROM AUTHOR]