Masomeh Ganji; Serolah Galeshi; Hamid Jabbari; Forough Sanjarian; Benjamin Torabi
Abstract
Objective: Water stress affects the crucial processes and yield of crops. This study aimed to investigate the effect of water stress on physiological and biochemical traits of safflower genotypes.Methods: A factorial experiment was carried out as randomized complete block design in Seed and Plant Improvement ...
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Objective: Water stress affects the crucial processes and yield of crops. This study aimed to investigate the effect of water stress on physiological and biochemical traits of safflower genotypes.Methods: A factorial experiment was carried out as randomized complete block design in Seed and Plant Improvement Research Institute during 2017-19. The treatments included two irrigation levels (40 and 80% depletion of available water) and Parnian, Goldasht and Kazak genotypes. Plants were sown in soil columns with a height of 150 and a diameter of 23 cm, and irrigated by a drip system. Antioxidant enzymes, malondialdehyde, proline, relative water content, chlorophyll, seed yield and fatty acid composition were measured at the end.Results: Water stress significantly increased the accumulation of hydrogen peroxide and malondialdehyde in safflower genotypes which led to increased catalase and peroxidase enzyme activity by 1 and 2.5 U, respectively. The proline content increased about 16 times under water stress conditions. In contrast, the relative water content showed a significant decrease, which resulted in increased canopy temperature and decreased seed yield by 70%. The Kazak genotype had the lowest increase in canopy temperature under stress conditions and showed higher yield stability. Moreover, the fatty acid composition of seed oil changed and the amount of linoleic acid decreased by 1.8% under water stress conditions.Conclusion: The results showed that in addition to drought-related physiological traits, no increase in saturated/unsaturated fatty acid ratio is also an important indicator in screening superior genotypes for cultivation in water shortage.
Hosna Fayazi; Ebrahim Zeinali; Afshin Soltani; Benyamin Torabi
Abstract
Global climate change is among the most important agricultural and food security challenges. This study tries to investigate the effect of climate change on potential yield and water productivity of forage maize (Zea mays L.) in Iran. Two scenarios of RCP4.5 and RCP8.5 are used to predict the future ...
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Global climate change is among the most important agricultural and food security challenges. This study tries to investigate the effect of climate change on potential yield and water productivity of forage maize (Zea mays L.) in Iran. Two scenarios of RCP4.5 and RCP8.5 are used to predict the future climate (2050s) and climate data of 2001-2015 have been used as the base period. Potential yield is estimated using SSM-iCrop2 model according to the GYGA protocol and the climate changes for both scenarios are applied in the model. The results show that the climate change will not have a considerable effect on forage maize yield compared to the current conditions (85.6 ton ha-1) and will only lead to an increase of 0.9% and 1.6% in on both scenarios, respectively. This may be attributed to maize being a C4 plant and thus non-effectiveness of CO2 increase on its growth. Also, the temperature will remain in optimum range for maize in most of the main regions for forage maize cultivation areas in Iran. Water productivity in both scenarios will increase by 0.4% and 1.6%, compared to current conditions (10.4 kg m-3), respectively, which may be due to increased CO2 concentration and more closure of stomata. Also, improved water productivity in forage maize may be attributed to increase yield potential due to the fact that no considerable changes are observed in terms of the required water, evapotranspiration and irrigation times.
samaneh rahban; Benjamin Torabi; afshin soltani; Ebrahim Zeinali
Abstract
The present study tries to estimate the yield gap of irrigated canola in Iran as the first step for planning sustainable improvement of production. It has been performed in the modeling laboratory of Gorgan University of Agricultural Sciences and Natural Resources in 2017-2019. The protocol provided ...
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The present study tries to estimate the yield gap of irrigated canola in Iran as the first step for planning sustainable improvement of production. It has been performed in the modeling laboratory of Gorgan University of Agricultural Sciences and Natural Resources in 2017-2019. The protocol provided by the GYGA project is used for detection of climatic zones as well as major weather stations in canola production regions to estimate the yield gap. The actual yield of the irrigated canola in its major production regions is between 1184 to 2358 kg ha-1. The range of potential yield is estimated between and 3823 and 6520 kg ha-1. The highest potential yields belongs to Hamedan and Lorestan provinces and the lowest value to Khuzestan Plain. The range of the yield gap in its major production regions in the country is 2480 to 4365 kg ha-1, i.e. 53% to 77% of gap and with an average, 3276 kg ha-1 equal to 65% of the gap. With respect to the exploitable yield as the target yield, the exploitable yield is between 1544 and 3208 kg ha-1, with an average of 2261 kg ha-1. The magnitude of this gap indicates that the potentials of canola production in Iran are not exploited properly. Analyzing the reasons and methods of amendment the present yield gap and adoption of efficient management methods to achieve higher yields is crucial with regard to food security and economic.
Benjamin Torabi; Najebullah Ebrahimi; Afshin Soltani; Ebrahim Zeinali
Abstract
The present study was conducted to parameterize the SSM_iCrop model and evaluate the prediction of growth and development of faba bean in Gorgan climate condition. This study was carried out on faba bean cv."Barkat" as split-plot in randomized complete block design with four replications at Gorgan University ...
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The present study was conducted to parameterize the SSM_iCrop model and evaluate the prediction of growth and development of faba bean in Gorgan climate condition. This study was carried out on faba bean cv."Barkat" as split-plot in randomized complete block design with four replications at Gorgan University of Agricultural Sciences and Natural Resources in 2015-2016. The experimental factors consisted of planting date (27 November, 25 December and 31 January) and plant density (5, 15, 25 and 35 plants/m2). The parameters of phonological stages, leaf expansion and senescence, production and distribution of dry matter and water balance were estimated using the present data experiment and other data. The results of model evaluation showed that, it can well predict, days to flowering (RMSE = 3.8 and CV =4.1), days to maturity (RMSE = 11.9 and CV= 8.1), node number on main stem (RMSE = 1.7 and CV = 10.0), leaf area index (RMSE =0.8 CV =28.8), biological yield (RMSE = 158.5 and CV =21.6) and seed yield (RMSE = 118.6 and CV = 24.7). Therefore, the SSM_iCrop model can be used to evaluate the agronomic management and analyze the growth and yield of faba bean in Gorgan conditions.
Yonus Mohammad Nezhad; Majid Basirat; Hossein HajiAbaee; Benjamin Torabi
Abstract
In the fields around Golestan dam, crop rotation is not performed, putting the soil fertility at risk. This experiment aims at evaluating the nutritional status of the region’s soils and determining the need for fertilizer with emphasis on macronutrients. The fertilizer requirement of these soils ...
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In the fields around Golestan dam, crop rotation is not performed, putting the soil fertility at risk. This experiment aims at evaluating the nutritional status of the region’s soils and determining the need for fertilizer with emphasis on macronutrients. The fertilizer requirement of these soils in 2017-2018 has been determined, using the QUEFTS model. At first, 30 fields in the Golestan dam region, irrigated by the dam itself, have been chosen. In each field, a small section has been selected as a non-fertilized one. All agronomic practices have been done in accordance with conventional farmers' method. From each field (fertilized and non-fertilized), five one-meter squared quadrats have been used to cut off the crop and the grain yield and non-grain yield, and measure its N, P, and K concentration. Results reveal that the mean value of N, P, and K uptake by shoots have been 54, 19.5, and 98 kg/ha, respectively, with the average grain yield being 4150 kg/ha in farmers' field. For 1000 kg of grain production per hectare, one requires 13, 4.5, and 22 kg of N, P, and K, respectively. Therefore, according to the proper validation results of the QUEFTS model, it is recommended to apply 325 kg/ha urea fertilizer, 195 kg/ha triple super phosphate fertilizer, and 60 kg/ha potassium sulfate fertilizer to produce about 5000 kg/ha wheat grain in this area.
mohsen malek; Farshid Ghaderi-Far; Benjamin Torabi; HamidReza sadeghipour
Abstract
To investigate the effects of drying methods (desiccation treatment), heat shock and osmotic stress treatments on the viability of primed seeds from different rapeseed cultivars, an experiment was conducted in 2017-2018 at the Seed Research Laboratory of Gorgan University of Agricultural Sciences and ...
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To investigate the effects of drying methods (desiccation treatment), heat shock and osmotic stress treatments on the viability of primed seeds from different rapeseed cultivars, an experiment was conducted in 2017-2018 at the Seed Research Laboratory of Gorgan University of Agricultural Sciences and Natural Resources. In this study, seeds of three canola cultivars i.e. Dk-xpower, Teraper and Hayola50, which had observed priming treatments, were exposed to desiccation, heat shock and osmotic stress treatments. Thereafter, to investigate the effects of different treatments, the treated seeds were subjected to controlled deterioration test. Finally, after fitting the three-parameter logistic model to germination percentage during controlled deterioration test, time for decrease of germination to 50% was Calculated and used as the criterion for comparing seed viability. Results showed that the response of rapeseed cultivars to different treatments were different. Also, priming methods and different treatments in drying phase of primed seeds, displayed different effects on seeds' lifespan. In general, heat shock treatments were found efficient in Dk-xpower and Traper cultivars as they increased seeds' lifespan. In contrast, osmotic stress treatments often had negative effects on seed viability in all canola cultivars. Even, "osmopriming" and subsequent slow drying of primed seeds had more negative effects than "hydroperiming" associated with fast drying methods.
Asieh Siahmarguee; Benjamin Torabi; Eid Mohammad Sohrabi Rad; Syed majid Alimagham
Abstract
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 ...
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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.
Najebullah Ebrahimi; Benjamin Torabi; Afshin Soltani; Ebrahim Zenali
Abstract
To analyze the growth, it is necessary to access to accurate and well-arranged data obtained from measuring leaf area and dry matter accumulation. The purpose of this study was to evaluate different nonlinear regression models to study the trend of changes in leaf area index and dry matter production ...
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To analyze the growth, it is necessary to access to accurate and well-arranged data obtained from measuring leaf area and dry matter accumulation. The purpose of this study was to evaluate different nonlinear regression models to study the trend of changes in leaf area index and dry matter production and to estimate the parameters related to the growth analysis. The experiment was conducted on faba bean "cv. Barkat" in a split-plot experiment based on randomized complete block design with three planting dates and four densities in four replications. In this study, the beta and logistic models were fitted to the leaf surface data and the beta, Gompertz and logistic models to dry matter production. AICc benchmark showed that the beta model was fitted to the leaf surface data the better than the logistic model. LAImax in different densities varied between 2.3 to 5.3, tm between 131.9 and 144.2, and te between 158.7 and 163.5 days after planting. AICc benchmark showed that the beta model was fitted to the dry matter accumulation data the better than the Gompertz and logistic models. Wmax in different densities varied between 725.1 and 1484.3 g/m2, tm between 138.3 and 146.4 and te between 162.60 and 179.0 days after planting. Grain yield varied from 231 to 2744 g/m2, and with increasing density in each planting date, grain yield showed the increased trend. The results showed that yield changes were directly affected by maximum leaf area index, maximum dry matter accumulation and crop growth rate.
Ali Mansouri rad; Ali Nakhzari Moghadam; Afshin Soltani; Ali Rahemi Karizaki; Benyamin Torabi
Abstract
One of the main problems of soybean production in the east region of Golestan, Iran is considerable difference between actual yield and attainable yield which is called yield gap. In recent years, this gap has been impressive, and therefore, identifying soybean yield-limiting factors is essentially needed. ...
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One of the main problems of soybean production in the east region of Golestan, Iran is considerable difference between actual yield and attainable yield which is called yield gap. In recent years, this gap has been impressive, and therefore, identifying soybean yield-limiting factors is essentially needed. The present study was conducted based on CPA method in 73 fields of Kalaleh )Golestan, Iran) in 2016. In this study all information related about management practices, soil characteristics and farmer socio-economic status were measured and recorded. Then, using stepwise regression, the relationship between variables and yield was considered. The results showed that there is a 2606.4 kg/ha difference (gap) between actual yield (average farmers' yield) and attainable yield (maximum farmers' yield). It was identified that farming experience, burying plant residues in the soil, planting date, Sprinkler irrigation, the amount of used water and plant density were contributed to yield gap, 30.1, 5.1, 14.7, 13.8, 13.8 and 22.5%, respectively. It could be concluded that improving these factors will increase the yield up to 1802.9 kg/ha.