Hydar Flayyih; Jafar Nabati; Ahmad Nezami; Mohammad Kafi; Mohammad Javad Ahmadi
Abstract
Introduction
The growth of chickpea plants is severely affected by salt stress, leading to a significant reduction in their performance. Therefore, identifying salt-tolerant genotypes of chickpea can greatly help improve plant resilience and enhance productivity under stressful conditions.
Materials ...
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Introduction
The growth of chickpea plants is severely affected by salt stress, leading to a significant reduction in their performance. Therefore, identifying salt-tolerant genotypes of chickpea can greatly help improve plant resilience and enhance productivity under stressful conditions.
Materials and methods
This research was conducted with the aim of studying the salt tolerance of Kabuli chickpea genotypes under field conditions in 2021-2022. Salt stress was applied at two levels: 6 and 9 dS.m-1, along with a control level of 0.5 dS.m-1. The genotypes were evaluated based on their response to these salt stress levels. The irrigation treatments were applied uniformly and complementarily in three stages for 12 genotypes: before flowering, during flowering, and pod filling. Sodium chloride was used to induce salt stress levels. The volume of irrigation water given to each plot was measured using a water counter, and the same amount of water was considered for all treatments.
Results and discussion
The investigation demonstrated changes in the levels of secondary metabolites and leaf chlorophyll content under salt stress conditions, depending on the plant genotype. In genotypes MCC52, MCC65, MCC77, and MCC92, salt stress reduced the content of plant pigments. The reduction in chlorophyll content in plants under the influence of salt stress is associated with an increase in the activity of chlorophyll-degrading enzymes, alterations in nitrogen metabolism, and the utilization of glutamate due to its involvement in the proline synthesis pathway. Increased scavenging activity of the free radical DPPH was observed in genotypes MCC12, MCC27, MCC28, MCC72, MCC92, and MCC108 under salt stress of 9 dS.m-1. The activity of the enzyme catalase increased in most studied genotypes under 6 dS.m-1 salt stress, but decreased with the increase in stress level to 9 dS.m-1. The highest activity of the enzyme ascorbate peroxidase was observed in genotype MCC29 under 6 dS.m-1 salt stress. The decrease in the osmotic potential in plants is a consequence of cellular water conservation under stress conditions. This is because, under salt stress, the plant needs to maintain a more negative water potential in order to absorb water. Therefore, there is a greater need to increase the concentration of compatible osmolytes. Plants with higher antioxidant capacity demonstrate better resistance to oxidative stress due to their ability to detoxify free radicals. The application of salt stress at a level of 9 dS.m-1 led to a significant increase in sodium content in all genotypes compared to the control treatment. In over 65% of the studied chickpea genotypes, applying 6 dS.m-1 salt stress resulted in an increase in potassium content in the plant, while 9 dS.m-1 salt stress reduced leaf potassium content. The reduction in potassium content in plants is due to the substitution of sodium in place of potassium and calcium. The competition between potassium and sodium ions for uptake sites in the roots is one of the factors that increases sodium content and decreases potassium content. Plant dry weight increased by 25% in genotype MCC72 and more than three times in genotype MCC108 under the highest level of stress compared to the control treatment. In genotype MCC108, the application of the highest level of stress also increased seed weight in the plant by approximately 73% compared to the control treatment. With the imposition of salt stress and the decrease in water potential within the plant, the weight of the plant is affected and decreases. Additionally, due to the disruption of nutrient balance and the effects of osmotic stress, growth is reduced, and the dry weight of the aerial parts also decreases.
Conclusion
In general, the results showed that the imposition of salt stress affected the growth and physiological traits of chickpea genotypes. Seed weight and plant dry weight decreased in all genotypes under salt stress conditions of 6 dS.m-1 compared to the control treatment. The studied genotypes were able to maintain their survival and growth under salt stress conditions through various mechanisms such as increasing antioxidant compounds, preserving relative leaf water content, increasing leaf chlorophyll content, enhancing the activity of antioxidant enzymes, and increasing the content of metabolites. Generally, there was a high diversity among the studied chickpea genotypes, suggesting that their use in improving salt tolerance in chickpea plants could be beneficial.
Hossein Hammami; Meisam Mirzaei Nasab
Abstract
IntroductionDrought as abiotic stress and weeds as biotic stress are the major factors that limit crop growth and production in the worldwide, especially in arid and semi-arid regions (Farooq et al., 2012; Abdolahi Norouzi et al., 2024). Drought is also considered the single most devastating environmental ...
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IntroductionDrought as abiotic stress and weeds as biotic stress are the major factors that limit crop growth and production in the worldwide, especially in arid and semi-arid regions (Farooq et al., 2012; Abdolahi Norouzi et al., 2024). Drought is also considered the single most devastating environmental stress, which reduces crop growth and productivity more than any other environmental stress (Farooq et al., 2012; Abdolahi Norouzi et al., 2024). The process of dehydration of plants in drought causes fundamental changes in water relations, biochemical and physiological processes, the structure of the membrane cells of the plant. Weeds decrease the growth and productivity of crops by competation for access to radiation, nutrients, and water. Under drought conditions, weeds have a high ability to compete with crops for resources. Moreover, weed management under drought conditions is harder than in normal conditions. Exposer of plant to drought conditions led to morphological, physiological, and biochemical changes in weeds that may affect herbicide performance (Ziska and Dukes, 2011; Alizadeh et al., 2021; Alizadeh et al., 2020; Benedetti et al., 2020). Alizade et al. (2020) concluded that drought restricts photosynthesis and stomatal conductance, reduces absorption, and the effectiveness of the herbicide benzoylpropethyl. Drought increased quinclorac resistance in Echinochloa crusgalli by inducing the metabolic activity of glutathione S-transferases (Wu et al., 2019). Therefore, this experiment was conducted to investigate the performance of clothodim in the control of littleseed canarygrass.Materials and methodsThe experiments of this study were conducted at the research greenhouse of the College of Agricultural, University of Birjand. To obtain maximum seed germination, seeds of littleseed canarygrass were soaked in potassium nitrate solution (2 g.L- 1) under dark conditions at 4 0C for one week. Then the seedlings were sown in 5 L plastic pots. According to Monaco et al. (2002) environmental factors one to two weeks before and after the use of herbicides can affect the absorption of herbicides. Therefore, the plants were grown under field capacity conditions until two weeks after sowing (at the 2-leaf stage). Then, pots were irrigated under three regimes every two days: 100% field capacity, 75% field capacity, and 50% field capacity. The irrigation treatments were conducted two weeks before and after herbicide application. Clethodim at seven levels (zero, 6.25, 12.5, 25, 50, 75, and 100 percent recommended per hectare (120 g.ai. ha-1)) was applied at four leaf stages. Four weeks after spraying herbicide, the shoots of plants were harvested and immediately weighted. Then, the samples were dried in the oven at 75 °C for 48 hours and reweighted. The roots were washed and separated from the soil by tap water three times. After surface drying, samples were weighted, dried, and reweighted. The experiment data were fitted using the three-parameter logistic equation, and the effective doses of 20, 50, 80, and 90% were calculated. Data analysis was done using SAS 9.4 and R software (drc package). Sigmaplot software was also used to draw the figures.Results and discussionThe three-parameter logistic regression model provided a reasonable description of the variation in fresh and dry shoots and roots weight for littleseed canarygrass as the applied clethodim doses increased. With increasing clethodim dose, the fresh and dry weight of shoot and root of littleseed canarygrass decreased in three irrigation regimes. However, the decreasing slopes among the irrigation treatments differed. Under 50% field capacity treatments, the effective dose of 90% inhibitor (ED90) on fresh and dry weight of shoots and roots was increased by 86.24%, 17.04%, 85.35%, and 32.51%, respectively. The higher ED90 under 50% field capacity compared to 100% field capacity showed decreased clethodim performance in littleseed canarygrass control. Drought is believed to reduce herbicide efficacy by reducing herbicide absorption, translocation and metabolism in plants. Increasing cuticle layer thickness and reducing the transfer rate of vascular sap, limit the absorption and translocation of herbicides in water-stressed plants (Ziska and Dukes, 2011; Alizadeh et al., 2021; Alizadeh et al., 2020; Benedetti et al., 2020). The degree of adverse effect of water stress on herbicide performance depends on the type of herbicide and weed population (Alizade et al., 2021).ConclusionIn general, the results of this experiment showed that the application of clethodim under drought conditions, led to decrease clethodim performance on littleseed canarygrass control. By severity of drought stress, performance decreases were higher than control (non stress treatment). The results of this experiment suggested adjusting the herbicide application with the irrigation time to maximize the effectiveness of the herbicide and decrease its consumption. However, further studies are needed in field conditions to prove these results and adjust herbicide doses in drought affected areas.
sedighe sedaghati; Reza Amiri Fahliani; Asad Masoumiasl; Moslem Bahmankar
Abstract
Introduction
Maize (Zea mays L.) is considered a strategic and essential product for global food security and is used in human food and animal feed. Recent droughts and, in some cases, the ban on planting maize as a water-consuming crop have caused the yield and cultivated area of this valuable crop ...
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Introduction
Maize (Zea mays L.) is considered a strategic and essential product for global food security and is used in human food and animal feed. Recent droughts and, in some cases, the ban on planting maize as a water-consuming crop have caused the yield and cultivated area of this valuable crop to decrease. Therefore, planning based on adaptation to drought is necessary for the sustainability of maize production. Water stress is one of the most critical environmental stresses in agriculture, so many efforts have been made to maintain plant yield under drought conditions. Water deficit stress negatively affects the growth and productivity of crop plants in various ways. Different crop plants have complex mechanisms that respond to water deficits. Drought resistance in these plants is influenced by several factors, including environmental humidity, the intensity of the stress, the phenological stage in which the stress occurs, and plant nutrition. The use of stress tolerance indices, which are calculated based on yield under stress and non-stress conditions, is effective in selecting high-yielding and stress-tolerant genotypes.
Materials and methods
The present experiment was carried out in the research farm of Yasouj University located in the Dashtrom region (51º E and 30º N, 1734 m altitude), Yasouj, Iran in 2023. To investigate the effect of drought stress on the yield and yield components of some maize hybrids to identify tolerant cultivars, the number of ten maize hybrids was evaluated in two separate experiments under normal and drought stress conditions in a randomized complete block design with three replications at the research farm of Yasouj University. The number of kernels per ear, the kernels per row, 200-kernel weight, grain yield, harvest index, stress susceptibility index (SSI), tolerance index (TOL), stress tolerance index (STI), geometrical mean productivity (GMP) and mean productivity (MP) were calculated. To check the homogeneity of variance in two experiments, Bartlett's test was performed for the evaluated traits. Analysis of variance based on combined analysis, mean comparison and principal components analysis was done using R software version 4.2.1, and some graphs were drawn using Excel software.
Results and discussion
The results of the combined analysis variance of the data showed that the interaction of Irrigation and genotype on the traits of kernel per ear, kernel per row, and 200-kernel weight was significant. In the same way, the results showed that the main effects of irrigation and genotype on grain yield, biological yield, and harvest index were significant. The results of mean comparisons showed that yield and yield components in all the studied genotypes decreased under stress conditions. Moreover, slicing the interaction effect of genotype at two irrigation levels indicated that genotype 1 was superior in terms of the number of kernels per ear and the 200-kernel weight compared with other genotypes and had more grain yield and biological yield. The results of principal components analysis based on tolerance indices located the studied genotypes in four regions and the first and second two components explained about 100% of the data variation. Considering that genotypes 1, 3, and 400 are located in region A, and give higher grain yield and yield components, it is recommended to plant in the region under normal and stress conditions. In addition, if there are no limitations on water resources, hybrids 4 and 410 may also be suitable.
Conclusion
Considering that genotype 1 had higher grain yield and yield components, and its performance stability, based on the biplot graphic representation, it was located in region A along with 3 and 400 hybrids. Therefore, it is recommended for planting in the region under stress-free and stressful conditions. In addition, if there are no restrictions on water resources in the region, in addition to this hybrid, hybrid 4 as well as 410 could be recommended.
Meysam Khavari; Mahmood Ramroudi; Ahmad Ghanbari
Abstract
Introduction
Plantago ovata is classified in the Plantaginaceae family. Water and nutrients are crucial determinants of plant growth. Multiple studies indicate that the optimal effectiveness of fertilization occurs when plants are not experiencing water stress, while irrigation is most effective when ...
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Introduction
Plantago ovata is classified in the Plantaginaceae family. Water and nutrients are crucial determinants of plant growth. Multiple studies indicate that the optimal effectiveness of fertilization occurs when plants are not experiencing water stress, while irrigation is most effective when nutrients are not limited. Drought stress is a complex form of stress that leads to alterations in the physiological, morphological, biochemical, and molecular characteristics of plants. Phosphorus is a vital nutrient necessary for the growth of plants. It facilitates plant maturation and promotes seed development. Intensive agriculture carries the potential for over-fertilization. Microorganisms play a crucial role in agriculture by facilitating the movement of plant nutrients and minimizing reliance on chemical fertilizers. Enhanced sowing techniques not only ensure the ideal number of plants by promoting better germination, but also allow for uniform and efficient utilization of land, light, and other input resources by the plants. Therefore, it is crucial to establish a planting arrangement that can prevent overcrowding and allow plants to optimize resource utilization with greater effectiveness and efficiency.
Materials and methods
The experiment was carried out as a split-factorial design with a randomized complete blocks arrangement. It was conducted at the research farm of Zabol University in Chah Nimeh, with three replications. The experimental treatments consisted of three levels of drought stress: irrigation after 60 mm (non-stress), 120 mm, and 180 mm evaporation from a class A evaporator (severe drought stress) as main factor. The sub-factor was the combination of seed planting method (flat or ridge planting) and phosphorus fertilizer types, which included 100% chemical phosphorus fertilizer, Phosphate Barvar2, and a combination of 50% chemical phosphorus fertilizer and Phosphate Barvar2. The following characteristics were analyzed: spike length, spike weight, spike density per square meter, grain yield per plant, individual plant dry weight, harvest index, grain protein content, mucilage percentage, seed husk percentage, and husk yield. The data analysis was conducted using SAS software version 9.1. To compare the means of treatments, Duncan's Multiple Range Test was employed with a significance level of 5%.
Results and discussion
The findings indicated that the non-stress irrigation treatment combined with the application of phosphorus fertilizers resulted in the highest values for spike length, weight of spike, number of spike per m-2, grain yield per plant, single plant dry weight, and husk yield. The comparison results of the means of the interaction effects of irrigation and phosphorus fertilizers showed that the highest grain yield per plant (2.271 gr) was observed with the non-stress irrigation treatment and the combined use of phosphorus fertilizers. On the other hand, the lowest grain yield (0.741 gr) was associated with the treatment of severe drought stress and non-application of phosphorus fertilizers. Additionally, the highest seed protein (2.305 mg.g-1 seed weight) and mucilage percentage (15.04) were obtained from the irrigation treatment after severs drought stress with the combined application of phosphorus fertilizers. The husk percentage, was influenced by phosphorus fertilizers and planting methods with different irrigation levels. Applying phosphorus fertilizers and utilizing a ridge planting technique, along with irrigation triggered after 180 mm of evaporation from the evaporation pan, resulted in a 32% increase when compared to the standard irrigation treatment and absence of fertilizer.
Conclusion
The utilization of phosphorus fertilizers resulted in a beneficial impact on both the quantity and quality attributes of grain yield per plant. The combined treatments had a more pronounced positive effect compared to applying phosphorus fertilizers individually. The primary factor contributing to the superiority of the flat planting method was the accelerated germination of seeds, which facilitated faster plant establishment. The research findings indicate that the most significant quantitative attributes of Plantago ovata were achieved through the irrigation treatment of 60 mm evaporation from the evaporation pan, coupled with the combined use of biological and chemical phosphorus fertilizers using the flat planting method.
Zohreh Falahati; Reza Amiri Fahliani; Masoud Dehdari; Hamid Reza KhademHamzeh
Abstract
Introduction
With the increasing population, ensuring food security is one of the most important challenges for humans. Oilseeds are considered strategic crops, and due to the role they play in providing fats, proteins, and vitamins, they are among the most important food sources. Water deficit and ...
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Introduction
With the increasing population, ensuring food security is one of the most important challenges for humans. Oilseeds are considered strategic crops, and due to the role they play in providing fats, proteins, and vitamins, they are among the most important food sources. Water deficit and drought stress severely reduce crop production and are the most significant abiotic stress worldwide, posing a crisis in Iran. Seed production and the sustainability of sunflower (Helianthus annuus) under drought stress are limited especially in arid and semi-arid regions. To understand the effects of stress on crops, it is essential to consider drought stress conditions in breeding programs to identify tolerant genetic materials. The response of sunflowers to drought stress depends on genotype, stress intensity, and the time of occurrence. Due to the annual damage caused by drought stress and the lack of sufficient information regarding the tolerance levels of different sunflower genotypes, the present study aimed to evaluate some common genotypes of sunflower under drought stress.
Materials and methods
This research was conducted in 1401 in the Dasht-e Roum region of Boyer-Ahmad County, Kohgiluyeh and Boyer-Ahmad Province, with geographical coordinates of 30° 34ʹ north latitude and 51° 31ʹ east longitude, at an altitude of 2095 m. Two separate experiments were performed in a randomized complete block design with three replications. The first experiment was conducted under non-stress conditions (providing 100% of the water requirement), and the second experiment was conducted under stress conditions (providing 50% of the water requirement). The experimental treatments included 10 genotypes, including oilseed sunflowers (Lakomka, Progress, Shams, Qasim, Golsa, Biotech, and Zarrin) and nut sunflowers (Shamshiri, Kalleh Ghoochi, and Pakan Bazaar). In April 1401, plowing operations were carried out, followed by the creation of furrows at a distance of 50 centimeters. Plots with dimensions of 4x3 meters were considered, and oilseed sunflowers were planted with a spacing of 20 centimeters between rows, while nut sunflowers were planted with a spacing of 25 centimeters. The planting depth was 5 centimeters in the last of June. Irrigation regimes were applied after the plants reached the 4 to 6-leaf stage.
Results and discussion
Based on the analysis of variance, the effect of genotype on the head diameter was not significant under stress conditions, but it was significant at the 1% level of probability under non-stress conditions. Under non-stress conditions, nut genotypes including Shamsiri, Local Pakan Bazar, and Kallegouchi did not show any significant difference in head diameter. Among the oilseed genotypes, Shams had the highest head diameter, although it did not show a significant difference compared to other genotypes except for the Zarrin genotype. Based on the combined analysis of variance, the main effect of genotype and irrigation regime was significant at a 1% level of probability on the number of filled grains per head. The comparison of the mean effect of the irrigation regime showed that with the application of drought stress, the number of filled grains per haed decreased by 20.03%. Among the oilseed genotypes, Ghassem had the highest and Biotech had the lowest number of filled grains per head. Among the nut genotypes, the local Pakan Bazar genotype had the highest number of filled grains per head, while the Kalleh Qouchi genotype had the lowest. The combined analysis of variance showed that the percentage of seed oil, hundred-seed weight, seed yield, and biological yield of sunflower were significantly influenced by genotype-by-irrigation regime interaction with 99% confidence. The comparison of mean oil percentage for genotypes at different levels of irrigation regime showed that under non-stress conditions, the Ghassem genotype had the highest oil percentage among the oilseed genotypes. Among the nut genotypes, the local Pakan Bazar genotype had a higher oil percentage compared to the Shamsiri and Kalleh Qouchi genotypes. Under stress conditions, the Golsa genotype showed the highest oil percentage. Among the nut genotypes, the Kalleh Qouchi and local Pakan Bazar genotypes had a higher oil percentage compared to the Shamsiri genotype. Under non-stress conditions, the Biotech genotype had the highest hundred-seed weight. Additionally, among the nut genotypes, the Shamsiri genotypes had the highest hundred-seed weight under this irrigation condition. Under stress conditions, among the oilseed genotypes, the Biotech genotype showed the highest hundred-seed weight. Similarly, among the nut genotypes, the Shamsiri genotype had the highest hundred-seed weight. The results of comparing the mean of genotypes at different levels of irrigation regime indicated a decrease in seed yield with the occurrence of stress. Under non-stress and stress conditions, among the nut genotypes, the Shamsiri genotype had the highest seed yield, while among the oilseed genotypes, the Shams genotype had the highest seed yield. Under non-stress conditions, the Shams genotype had the highest biological yield, although the local Pakan Bazar genotype did not show a significant statistical difference compared to the Shamsiri genotype. Under stress conditions, among the oilseed genotypes, the Shams and Golsa genotypes had the highest biological yield. Among the nut genotypes, the Shamsiri genotype also had the highest biological yield.
Conclusion
Based on the obtained results and the response of different sunflower genotypes in the present study, the Shams genotype among the oilseed types and the Shamsiri genotype among the nut types can be considered tolerant genotypes to water deficit for cultivation.
Sajad Saedi; Seyed Ali Mohammad Modarres-Sanavy; Ali Heidarzadeh
Abstract
Introduction
Drought is one of the most significant abiotic stresses that negatively affects agricultural productivity worldwide. More than 60% of global agricultural production is directly or indirectly impacted by drought stress. Water deficiency during any stage of plant growth, especially during ...
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Introduction
Drought is one of the most significant abiotic stresses that negatively affects agricultural productivity worldwide. More than 60% of global agricultural production is directly or indirectly impacted by drought stress. Water deficiency during any stage of plant growth, especially during critical periods such as flowering or seed filling, can result in substantial and often irreversible yield losses. The severity of drought's impact varies depending on the plant species and cultivar, ranging from high sensitivity to moderate or high levels of tolerance. In this context, adopting strategies that can enhance drought tolerance in crops is of paramount importance. Among such strategies, foliar application of essential nutrients—including iron (Fe), urea, and amino acids—can play a critical role by improving nutrient use efficiency and enhancing plant stress tolerance. Foliar feeding, due to its rapid absorption compared to soil-based nutrient application, is particularly important under water-deficit conditions. Urea, owing to its small molecular size, non-ionic nature, and high solubility, is readily absorbed through the leaf surface and plays a significant role in plant metabolism and growth. Iron is a vital micronutrient involved in key physiological processes, especially chlorophyll synthesis and photosynthesis. Its deficiency, particularly in calcareous soils, can cause chlorosis and decreased productivity. Foliar application of iron in the form of iron chelate (Fe-EDTA) is a widely used method to correct iron deficiencies in field crops. Moreover, amino acids are increasingly recognized as biostimulants that enhance plant physiological functions, improve growth parameters, and increase tolerance to environmental stresses such as drought. They contribute to improved antioxidant activity, membrane stability, and nutrient uptake, which are essential during stress conditions. Safflower (Carthamus tinctorius L.) is an annual oilseed crop that has gained attention due to its wide adaptability and multi-purpose use in the food, pharmaceutical, dye, and oil industries. Owing to its deep root system and moderate drought tolerance, safflower is a suitable candidate for evaluating the effectiveness of foliar nutrient applications under water-deficit conditions.
Materials and methods
This experiment was carried out as a split-plot design based on randomized complete blocks in the research farm of the Faculty of Agriculture of Tarbiat Modares University, during the 2022-23 growing season. The treatments were include three levels of irrigation regimes [no interruption of irrigation (full irrigation), withholding irrigation from the flowering stage, withholding irrigation from the seed filling stage] in the main plots and nine levels of Foliar spraying (no foliar spraying, distilled water, iron chelate 6% (Fe), urea 1% (U), amino acids 1 g.lit-1 (AA), Fe+U, Fe+AA, U+AA, Fe+U+AA) were placed in sub-plots. Analysis of variance (ANOVA) and also mean comparisons were accomplished using the general linear model (GLM) procedure. LSD procedure at a probability level of 0.05 was used to determine statistically significant differences among treatment means.
Results and discussion
The results showed that the highest oil content with 15.92% was obtained from Fe foliar application in the condition of withholding irrigation from the seed filling stage. Also, the interaction of foliar application and irrigation regimes had a significant effect on safflower seed yield, and foliar application of Fe+AA+U increased safflower yield. The highest amount of oil yield was produced from the Fe+AA+U in the condition of withholding irrigation from the seed-filling stage with 359.08 kg.ha-1. The highest amount of seed yield in the condition of full irrigation was obtained from the AA+U with 2333.33 kg.ha-1.
Conclusion
The results of this study highlight the positive impact of foliar application of iron chelate, urea, and amino acids—particularly when applied in combination—on the growth, seed yield, and oil content of safflower under both normal and drought-stressed conditions. The combined foliar treatment of iron, urea, and amino acids (Fe+U+AA) proved to be the most effective in enhancing oil yield and overall crop performance, especially under irrigation withholding from the seed filling stage. Additionally, the amino acids and urea combination (AA+U) performed best under full irrigation, suggesting a role in promoting productivity even in the absence of stress. These findings support the use of targeted foliar nutrition as an efficient strategy to mitigate the adverse effects of water stress in safflower cultivation. The synergistic effect of micronutrients and biostimulants can not only improve plant tolerance to drought but also sustain economic yield levels under limited water availability. Therefore, it is recommended that safflower farmers, particularly in semi-arid and arid regions, consider integrating foliar application of iron, urea, and amino acids into their agronomic practices. Moreover, moderate irrigation management, such as withholding water from the flowering stage along with foliar feeding, may optimize resource use and yield outcomes in water-limited environments.
Mohadeseh Shamsaddin Saeid; Rozita Kabiri
Abstract
Introduction
Several environmental factors affect growth, development, and finally crop yield. Water scarcity is one of the environmental stresses that has destructive and harmful effects on the growth stages of plants, their organ structure and activity, eventually causing oxidative stress by disturbing ...
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Introduction
Several environmental factors affect growth, development, and finally crop yield. Water scarcity is one of the environmental stresses that has destructive and harmful effects on the growth stages of plants, their organ structure and activity, eventually causing oxidative stress by disturbing the balance between the production of reactive oxygen species and the plant’s antioxidant defense system. In this regard, the induction of drought tolerance in plants is prominent from both theoretical and practical points of view. The application of plant growth regulators for survival, production of biomass, and yield in plants could be a promising approach that allows the farming of plants in the extension of cultivation fields and the increase of species diversity in natural and agricultural ecosystems. Methyl jasmonate (MeJA) is one of the compounds that is effective in causing tolerance and resistance to water scarcity in plants. Due to the role of jasmonic acid in drought tolerance induction in plants under stress conditions and considering the importance of Lepidium sativum in human nutrition, the main purpose of the present study was to investigate the effects of water scarcity and the foliar application of MeJA on the enzymatic antioxidant defense system, membrane stability and osmotic regulators. The mechanisms underlying drought tolerance are crucial for enhancing plant resilience and agricultural sustainability.
Materials and methods
To evaluate the effect of MeJA foliar spraying on some physiological indices and antioxidant enzymes activity of Lepidium sativum under water scarcity conditions, an experiment was conducted in a factorial arrangement based on a complete block design with three replications in the research greenhouse of the Bardsir Faculty of Agriculture, Shahid Bahonar University of Kerman, in 2022. The experimental treatments included the exogenous application of MeJA (0 (control), 50, and 100 μM) and irrigation level (100 and 50% of field capacity). Spraying distilled water and foliar application of MeJA concentrations on the leaves of the garden cress plant were applied based on the design plan, two times a week, and approximately 30 ml of MeJA was sprayed on each plant. Plant water depletions were determined by weighing the pots.
Results and discussion
The results showed that water scarcity caused a significant decrease in the amount of protein and an increase in the peroxidation content of membrane lipids, accompanied by the leakage of electrolytes. Although under water scarcity, the activity of antioxidant enzymes including superoxide dismutase(SOD), catalase (CAT), glutathione peroxidase (GPX), and ascorbate peroxidase (APX), as well as osmotic regulators consisting of proline content and soluble sugars increased by approximately 59.2, 74.3, 62.8, 62.7, 77.5, and 40.3%, respectively, as compared to the control plants, it was determined that the inhibition of ROS was beyond the tolerance of garden cress. Therefore, reducing the content of MDA (36.2%) and ion leakage (26.7%) and increasing the protein content by 23.5% through the induction of plant defense mechanisms, including amelioration of antioxidant enzyme activity and osmolytes, has been effective only by spraying the concentration of 100 µmol MeJA in garden cress under water scarcity conditions. MeJA exogenous application markedly ameliorated the water scarcity tolerance by increasing the activities of antioxidant enzymes and compatible osmolytes.
Conclusion
Based on the obtained results, it can be concluded that MeJA as a messenger molecule by increasing the activities of enzymatic antioxidants (SOD, CAT, GPX and APX) and increment osmotic regulators (proline and soluble sugars) in the cell led to decrease in lipids peroxidation and reduce in MDA content, which caused cell membrane stability, decline in ion leakage, and raising dry weight under water scarcity conditions. Therefore, it seems that the application of methyl jasmonate in modern agriculture can be a crucial step towards achieving agricultural sustainability in the country.
Amir Mohammad Abedi; Seyed Ali Mohammad Modarres-Sanavy; Ali Heidarzadeh
Abstract
IntroductionDue to the water crisis, the import of oil and oilseeds and the outflow of foreign currency, the need to cultivate oilseeds with low input consumption is felt. Camelina (Camelina sativa L.) is considered as a superior option as an oilseed crop with high growth capacity under stress conditions, ...
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IntroductionDue to the water crisis, the import of oil and oilseeds and the outflow of foreign currency, the need to cultivate oilseeds with low input consumption is felt. Camelina (Camelina sativa L.) is considered as a superior option as an oilseed crop with high growth capacity under stress conditions, in infertile soils and in temperate climate. This plant, with a short life cycle between 85 and 100 days, is suitable for cultivation in different agricultural and environmental conditions.Camelina seeds are rich in oil and protein. Camelina oil contains essential fatty acids such as omega-3 and omega-6, tocopherols, phytosterols, and phenolic compounds. Its applications include human nutrition, livestock and poultry feed, biodiesel production, and use in the biopolymer industry. Zeolites are three-dimensional aluminosilicate minerals that contain cations necessary to balance the electrostatic charge of the framework’s tetrahedral aluminum and silicon units. They can effectively combat soil pollution, water contamination, and heavy metal pollution. Additionally, zeolites can enhance water use efficiency and prevent food wastage in dryland areas, leading to increased crop yield. Wood vinegar, also known as pyroligneous acid, is a raw liquid with a reddish-brown hue produced through the biochar pyrolysis process. It mainly contains compounds such as acetic acid, butyric acid, catechol, and phenol. Wood vinegar has properties similar to plant growth regulators and is environmentally friendly. It can also enhance crop resistance to biological and abiotic stress factors.Materials and methodsThis design was implemented in the form of factorial split plots in the form of a randomized complete block design in three replications. The investigated factors include irrigation regimes at four levels (optimum irrigation, mild water deficit, moderate water deficit and severe water deficit) as main plots, natural zeolite (clinoptilolite) factorial at two levels (zero and eight tons per hectare) and wood vinegar at four levels (0, 5000, 10000, and 15000 ppm) were as sub-plots.Results and discussionThe results of the experiment indicate that irrigation regimes, the application of zeolite, and wood vinegar foliar spray have a significant impact on the morphological, physiological, and yield-related traits of the Camelina plant. The highest leaf area index was achieved in the treatment combining mild water deficit, zeolite application, and wood vinegar foliar spray with a concentration of 5,000 ppm. Additionally, the treatment involving wood vinegar foliar spray of 15,000 ppm and zeolite under optimal irrigation conditions resulted in the highest oil yield. The maximum water use efficiency based on seed and oil yield was observed in the treatment with severe water deficit, no zeolite application, and wood vinegar foliar spray at a concentration of 10,000 ppm. Furthermore, the photosynthetic rate was also higher in the treatment with optimal irrigation, zeolite application, and wood vinegar foliar spray of 15,000 ppm compared to other treatments. Based on the findings of this study, the use of zeolite and wood vinegar foliar spray at 15,000 ppm is recommended as the best treatment due to increased performance. Additionally, under mild and moderate water deficit conditions, the application of zeolite and wood vinegar foliar spray of 15,000 ppm is advised, while severe water deficit conditions do not warrant the use of zeolite and wood vinegar foliar spray of 10,000 ppm.ConclusionAccording to the results of this research, the use of zeolite and foliar spraying of 15000 ppm of wood vinegar is introduced as the best treatment due to the increase in seed and oil yield. Also, in mild and medium low water conditions, the use of zeolite and foliar spraying of 15000 ppm of wood vinegar is recommended, and in severe water deficit stress conditions, it is recommended not to use zeolite and foliar spraying of 10000 ppm.
Hamed Aflatooni; Omid Sofalian; Hassan Zali; Ali Asghari
Abstract
Introduction
Temperature is a major abiotic factor for regulating both growth and development of crop. But heat stress due to high ambient temperature is a serious threat to crop production worldwide. Heat stress is one of the major challenges in barley cultivation because it coincides with the flowering ...
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Introduction
Temperature is a major abiotic factor for regulating both growth and development of crop. But heat stress due to high ambient temperature is a serious threat to crop production worldwide. Heat stress is one of the major challenges in barley cultivation because it coincides with the flowering period and limits the crop productivity.
Materials and methods
To identify heat-tolerant genotypes, 17 promising genotypes of hull-less barley with three check genotypes were evaluated at the Darab Agricultural Research Station. The evaluation was conducted in a randomized complete block design with three replications at cropping year (2022-2023), under conditions non-stress and heat stress. The studied genotypes were planted in six lines along 6 m at a distance of 15 cm from each other. Seed consumption was determined by 400 seeds per square meter and thousand kernel weight for each genotype. Seeds were sown using an experimental plot planter (Wintersteiger, Ried, Austria). The fertilizer composition was 150 kg ha-1 nitrogen (twice), and di-ammonium phosphate and potassium sulfate were 100 and 50 kg ha-1, respectively (before planting). After the removal of perimeter plants, all experimental plots were harvested with an experimental grain harvester (Wintersteiger, Ried, Austria). The indices of stress tolerance studied were Yp: yield under non-stress condition; Ys: yield under stress condition; TOL: tolerance index; SSI: stress susceptibility index; MP: mean productivity; GMP: geometric mean productivity; STI: stress tolerance index; HM: harmonic mean; YI: yield index; YSI: yield stability index; RSI: relative stress index. Indices of FAI-BLUP (Factor analysis and ideotype-design), SIIG (selection index of ideal genotype), CSI (combination of significant indices) and MGIDI (multi-trait genotype-ideotype distance index) were used in order to integrate different indices of heat tolerance and better selection of genotypes in terms of heat tolerance.
Results and discussion
The results of the variance analysis for grain yield indicate a significant difference among genotypes at a 1% probability level in both heat stress and non-stress conditions. Heat stress led to a 24.8% decrease in grain yield in the examined genotypes. The results showed that based on the MP, GMP, HM and STI indices, genotypes 10, 16, 9 and 11 with the highest values of these indices were stress tolerant genotypes. Genotypes 6, 5, 3 and 18 with the highest values of RSI and YSI, respectively, were among the best genotypes. Based on the YI index, genotypes 10, 16, 5 and 6 with the highest YI value were introduced as stress-tolerant genotypes. The results of TOL and SSI indices showed that genotypes 6, 5 and 3 with the lowest values of these indices were tolerant genotypes. Positive and significant correlations were observed between the SIIG, FAI-BLUP, and CSI indices with Yp and Ys, while the MGIDI index showed negative significant correlations with Yp and Ys. The principal component analysis, capturing 99.8% of the variance in the relationships between the indices, grouped stress tolerance indices into three categories and genotypes into four groups. Genotypes 10, 16, and 9, with the highest values of SIIG, FAI-BLUP, and CSI indices and the lowest MGIDI values, were classified as heat tolerant genotypes.
Conclusions
In total, the results showed that by selecting indicators that have a significant correlation with grain yield in both stressed and non-stressed conditions and integrating them using combined indicators, the efficiency of selection increases. On the other hand, the results of FAI-BLUP, SIIG, MGIDI and CSI combined indices were completely similar in selecting the best genotypes and did not have any superiority over each other. Also, based on the results of the combined indices, genotypes 10, 16 and 9 were the superior barley genotypes in terms of tolerance to heat stress at the end of the season.
Zahra Zamani; Reza Tamartash; Mehdi Ghajar Sepanlu; Zeinab Jafarian Jelodar
Abstract
Introduction
Drought stress is always one of the main agricultural problems in Iran and the world and is considered an important factor in reducing plant yield, which is defined as a deviation from optimal conditions in plants. Zeolites are porous water-holding aluminosilicate minerals that contain ...
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Introduction
Drought stress is always one of the main agricultural problems in Iran and the world and is considered an important factor in reducing plant yield, which is defined as a deviation from optimal conditions in plants. Zeolites are porous water-holding aluminosilicate minerals that contain many beneficial elements and have high ion exchange capacity. So that their use in plant growth media with the aim of improving soil structure by increasing water retention capacity in the soil can moderate the harmful effects of drought stress on plants. The aim of the present study is to investigate the effect of different amounts of zeolite on the performance of Sanguisorba minor rangeland plants at different levels of drought stress. Assuming that using zeolite superabsorbent can reduce the negative effects of drought stress on plants and provide the best amount of zeolite use in optimal growth conditions combined with stress.
Materials and methods
For this purpose, an experiment was conducted in the greenhouse of the Faculty of Natural Resources of Sari in a completely randomized design with 3 replications. The first factor included zeolite at three levels of 0, 2 and 4% by weight per kilogram of soil and the second factor was the irrigation regime at three levels (20 (as control), 40 and 60% field drainage) applied to Sanguisorba minor seedlings. To create each level of drought stress, the method of daily weighing of pots and irrigation according to field capacity was used. For seed cultivation, 20 Sanguisorba minor seeds were sown in plastic pots at a depth of one centimeter and each pot was considered as an experimental plot. The pots containing zeolite treatments were regularly irrigated with ordinary water until the establishment stage of Sanguisorba minor seedlings (two-leaf stage) and after this stage they were irrigated until the end of harvest to apply drought stress. Number of seedlings The greened plants were reduced to three plants after the adverse factors were eliminated. The experiment continued until the control treatment had normal growth in the greenhouse. Finally, the analysis of variance of the data and comparison of the means were performed based on Duncan's test at a probability level of 5% (P<0.05) in SPSSvar22 software. The graphs were also drawn using Excell software.
Results and discussion
The results of the analysis of variance of vegetative characteristics of Sanguisorba minor plant under drought and zeolite stress indicated that drought and zeolite alone and their interaction effects were significant on all investigated variables except the dry weight of aerial parts. Also, the results of comparing the average vegetative characteristics showed that at each level of field capacity depletion, with increasing amount of zeolite, the desired traits increased and showed more favorable growth.The results of the correlation coefficient between the traits measured in the Sanguisorba minor plant under drought stress and zeolite also showed that there is a high correlation (r≥0.8) among all the traits at the level of 1%.
Conclusion
According to the obtained results, it can be said that Sanguisorba minor is a relatively resistant plant to drought stress, and adding zeolite to the cultivation medium of this plant in water deficit conditions can moderate the drought stress on the plant, so that the plant in the condition of 40% depletion of field capacity with 4% weight of zeolite, it continues to grow optimally. Also, from the results of the present study, it can be concluded that the use of zeolite can prevent water loss in the condition of dehydration and provide it to the plant, and due to the compatibility of this mineral with nature and its affordable price, its use in the condition Dehydration is recommended. Therefore, it is suggested that by conducting studies on different plant species, drought-tolerant plants can be more accurately identified and introduced in order to use them to create drought-resistant vegetation in agricultural fields and rangelands.
Maryam Harati Rad; Nafiseh Mahdinezhad; Reza Darvishzadeh; Baratali Fakheri; Mitra Jabari; Sorour Arzangh
Abstract
Introduction
Maize, like other plants, faces various environmental constraints during its growth period, such as the lack of nutrients. In calcareous soils, zinc deficiency reduces growth and yields. One of the important methods for improving tolerance to environmental stresses is the study of plant ...
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Introduction
Maize, like other plants, faces various environmental constraints during its growth period, such as the lack of nutrients. In calcareous soils, zinc deficiency reduces growth and yields. One of the important methods for improving tolerance to environmental stresses is the study of plant genotypes under stress conditions. In order to distinguish genotypes tolerant to stressful conditions, several tolerance indices are used. Genotypes are divided into 4 groups based on their reactions to normal and stressful environmental conditions. Group A includes genotypes that show good performance in both stress and normal conditions. Group B includes genotypes that show good performance only in stress-free environment. Group C includes genotypes that show good performance only in stressful environment and group D includes genotypes that show low performance in both stress and normal conditions. This experiment was carried out with the aim of evaluating the tolerance of maize genotypes to zinc deficiency by using stress tolerance indices.
Materials and methods
Ninety-three maize genotypes were evaluated morphologically under optimal and zinc deficiency conditions using alpha lattice design with two replications in field conditions at Zabol Agriculture and Natural Resources Research Center, during 2 successive crop years (2020 and 2021). Based on the grain yield of maize genotypes under optimal and zinc deficiency conditions, 10 stress tolerance indices including tolerance index (TOL), mean productivity index (MP), geometric mean productivity index (GMP), stress tolerance index (STI) , abiotic tolerance index (ATI), stress sensitivity index (SSI), drought stress resistance index (DI), harmonic mean (HM), modified stress tolerance index (MPSTI), and modified stress tolerance index in moderate and severe stress (MSSTI) were calculated. Pearson's and partial correlations between indices were calculated using corrplot package in R and SPSS version 26 softwares. A three-dimensional diagram was drawn to identify genotypes tolerant to zinc deficiency with high yield in both normal and zinc deficiency conditions using Statistica version 10 software, in which the grain yield under stress conditions was considered on the X axis, grain yield in optimal conditions was considered on the Y axis and one of the selected indices was considered on the Z axis. Principal components analysis and hierarchical clustering using Ward's method on standardized data were done using the factoextra and Cluster packages in R software, respectively.
Results and discussion
Based on the results of analysis of variance, statistically significant difference was observed among the studied maize genotypes in terms of grain yield under optimal and zinc deficiency conditions, as well as all calculated stress tolerance indices. The t-test showed statistically significant difference between the average seed yield of the genotypes in optimal (77.85 g pl-1) and zinc deficiency onditions (61.86 g pl-1). Grain yield in optimal conditions showed a positive and significant correlation with all indices except DI index. The highest correlation was related to MP, MpSTI, GMP, STI, ATI and HM indices. Grain yield under zinc deficiency conditions showed a negative and significant correlation with SSI (-0.45), TOL (-0.41) and ATI (-0.28) indices. Other indices showed a positive and significant correlation with grain yield under zinc deficiency conditions. The positive and significant correlation of GMP, MP, STI and HM indices with grain yield in both optimal and zinc deficiency conditions indicates that these indices are the best and most appropriate indices to identify and select maize genotypes tolerant to deficiency stress. Principal component analysis showed that the first two components explained about 95.42% of total variations. Cluster analysis classified maize genotypes into 5 groups comprising 27, 9, 23, 17 and 17 genotypes per each group, respectively. The genotypes classified in group 4, 2 and 1 were identified as highly tolerant (stable), tolerant and sensitive to Zn deficiency stress, respectively.
Conclusion
High genetic diversity was obtained between the studied genotypes in terms of grain yield and stress tolerance indices. Using the three-dimensional diagram, the genotypes tolerant to zinc deficiency with high yield in both optimal and zinc deficiency conditions were separated from each other. Also, the use of multivariate analyses was not only able to differentiate high-performance genotypes in both optimal and stress conditions, but also distinguished stable genotypes in stress conditions from unstable genotypes. So, Ma004, Ma027, Ma028, Ma038, Ma045, Ma083, Ma091, Ma105, Ma115 genotypes can be introduced as tolerant to zinc deficiency with stable performance for use in breeding programs.
Fatemeh Pirmoradi; Abdelmehdi Bakhshandeh; SeyedAmir Moosavi; Mohammad Hossain Gharineh; Ali Moshatati
Abstract
Introduction
Seeds play a crucial role in the reproduction and dispersal of plants. Ziziphus nummularia is a valuable plant species suitable for cultivation in arid and semi-arid regions of Iran. This plant can provide ground cover, increase biodiversity, and produce raw materials for the pharmaceutical ...
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Introduction
Seeds play a crucial role in the reproduction and dispersal of plants. Ziziphus nummularia is a valuable plant species suitable for cultivation in arid and semi-arid regions of Iran. This plant can provide ground cover, increase biodiversity, and produce raw materials for the pharmaceutical industry Z. nummularia is well-adapted to dry and low-rainfall areas and can be cultivated and utilized as a multipurpose plant for forest restoration and the production of valuable medicinal materials. Successful planting and establishment of a plant species by humans depend on the availability of high-quality seeds and the necessary knowledge of its response to environmental stresses. Water resource limitations and changes in precipitation patterns and distribution due to climate change are among the most serious challenges facing most regions of the world. For the propagation of valuable plants such Z. nummularia, it is necessary to investigate and study the role of these stresses, particularly during the germination stage, which is one of the most sensitive stages of plant life. The present study was conducted to investigate the simultaneous effect of temperature and salinity stress on the germination of Z. nummularia seeds.
Materials and methods
The present study was conducted to investigate the simultaneous effect of temperature and drought stress on the germination of sandy ziziphus seeds. The experiment was carried out as a factorial based on a completely randomized design with three replications. The experimental treatments included germination temperatures (5, 10, 15, 20, 25, 30, 35 and 40 degrees Celsius) and water stress levels (-0.2, -0.4, -0.6, -0.8, -1, -1.2, -1.4 MPa) that were created using polyethylene glycol 6000. Each experimental unit consisted of a petri dish with a diameter of 10 cm and 5 ml of osmotic solution was poured into each container. There were 25 sandy ziziphus seeds in each petri dish and they were transferred to germinators with a specified temperature setting for germination test. Each experimental treatment was repeated three times. The germination characteristics of the seeds included: final germination percentage, germination speed coefficient, mean germination time and germination index, which were calculated based on counting the germinated seeds 24 hours after the start of the experiment and every day at the same fixed time. Seeds with a radicle length of 2 mm or more were considered germinated. Also, the length of the root and stem, as well as the seed vigor, were measured and reported.
Results and discussion
The results of this experiment showed that under non-water stress conditions, seed germination began at 15°C up to a water potential of -0.4 MPa. With increasing water stress to -0.6 MPa, seeds were no longer able to germinate. Under non-water stress conditions, maximum germination was observed at 25°C (66.54%), which showed no significant difference from germination at 20 (52%), 30 (33.53%), and 35 °C (66.52%). At a water stress level of -0.2 MPa, Z. nummularia seed germination at 20, 25, 30, and 35°C was 66.28%, 66.48%, 66.44%, and 33.41%, respectively. The results showed that non-water stress conditions and 25°C resulted in the highest germination rate (24.42 seeds per day). With increasing water stress intensity to -0.2 MPa, the germination rate index significantly decreased at all temperature levels from 15 to 40°C, with a significant decrease at 25°C. The germination rate index was minimized at a water stress level of -0.8 MPa. The highest vigor index of Z. nummularia seeds was observed under non-water stress conditions and at 25°C (8.172). Increasing water stress level to -0.2 MPa resulted in a significant decrease in the vigor index, especially at 25°C (9.142).
Conclusion
Z. nummularia seed germination exhibits differential sensitivity to water stress under fluctuating temperature conditions. Z. nummularia was unable to germinate at temperatures below 10°C, and with increasing temperatures to 15 and 20°C, germination showed a significant increase in both percentage and germination index. Water stress beyond -0.2 MPa caused a significant decrease in most germination indices, including germination percentage, germination rate index, germination index, radicle length, hypocotyl length, and seedling vigor index (length), reaching a minimum at -0.8 MPa and resulting in germination inhibition.
Kimia Momeni-Shijani; Seyed Ali Mohammad Modarres-Sanavy; Ali Heidarzadeh; Amir Mohammad Abedi
Abstract
Introduction
One of the challenges facing the world today, despite the considerable growth in food production over the past half century, is how to address the issue of providing food for a population of approximately nine billion in the twenty-first century. In Iran, due to population growth and changes ...
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Introduction
One of the challenges facing the world today, despite the considerable growth in food production over the past half century, is how to address the issue of providing food for a population of approximately nine billion in the twenty-first century. In Iran, due to population growth and changes in dietary habits, the consumption of vegetable oils has significantly increased over the past four decades. Considering the shortage of edible oil in the country and the high level of oil imports threatening the food security of the society, the necessity of assessing the resources and comprehensive planning for the development of oilseed cultivation and attention to new oil sources is more emphasized than ever.
Materials and methods
This experiment was conducted in a randomized complete block design with split-split plot arrangements in three replications. The main factor consisted of different irrigation regimes at the plant flowering stage at four levels (severe water scarcity: cessation of irrigation until the plant-available moisture in the root zone reaches 20%, then irrigation to the agricultural capacity limit. Moderate water scarcity: cessation of irrigation when the plant-available moisture in the root zone reaches 40%, then irrigation to the agricultural capacity limit. Mild water scarcity: cessation of irrigation when the plant-available moisture in the root zone reaches 60%, then irrigation to the agricultural capacity limit. Optimal irrigation (without stress): cessation of irrigation when the plant-available moisture in the root zone reaches 80%, then irrigation to the agricultural capacity limit). The subsidiary factor included the application of nitrogen fertilizer from urea source as foliar spray at six levels (1%, 2%, 3%, 4%, distilled water foliar spray, and no foliar spray).
Results and discussion
Based on the results obtained, it can be concluded that plant height and straw yield showed the highest values under optimal irrigation conditions, while these values decreased under mild and moderate water scarcity conditions. The highest leaf area was observed in urea fertilizer foliar spray treatments at 2%, 3%, and 4% concentrations under optimal irrigation conditions, and in the 4% urea fertilizer foliar spray treatment under mild water scarcity conditions. The highest yield was observed in the optimal irrigation treatment. However, under mild water scarcity conditions, a reduction in seed yield compared to optimal irrigation was observed. The use of urea fertilizer foliar spray also increased seed yield compared to the control (no foliar spray), especially at 2% and 3% concentrations. The total chlorophyll content of leaves was highest under optimal irrigation conditions. According to the results, under mild, moderate, and severe water stress, total chlorophyll content decreased by 10.19%, 21.40%, and 52.71%, respectively, compared to the control with optimal irrigation. Additionally, urea foliar spray resulted in increased plant height, straw yield, seed yield, biological yield, harvest index, and total chlorophyll content, with the 2% concentration showing the highest increase in some traits. Drought stress leads to disrupted flowering, incomplete grain filling, and ultimately reduced crop yield. Water deficit conditions during the flowering stage increase pollen abortion. Additionally, during pollen fertilization, reduced photosynthesis intensity, increased abscisic acid hormone levels, and decreased loading of photosynthetic materials occur, ultimately causing flower and pod shedding and reduced yield. These results indicate that urea foliar spray can lead to significant improvements in physiological and yield traits of camelina plants under drought stress conditions. Therefore, based on the results of this experiment, optimal irrigation treatment and 2% urea fertilizer foliar spray are recommended as the best treatments. Additionally, mild water scarcity and urea fertilizer foliar spray at a concentration of 2% are recommended due to their desirable yield.
Conclusion
Based on the results obtained from this experiment, the treatment of adequate irrigation and 2% urea foliar spray is introduced as the best treatment. Additionally, mild deficit irrigation and urea foliar spray with a concentration of 2% are recommended due to their desirable yield.
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