Breeding plants for stress conditions
Akram Abasmanesh; Arash Fazeli; Reza Haghi Darehdeh
Abstract
IntroductionCereals are among the most vital agricultural products on a global scale, with an estimated annual production of around 904 million tons. Barley (Hordeum vulgare), a species within the Gramineae family, ranks as the fourth most important grain crop worldwide based on production. It is also ...
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IntroductionCereals are among the most vital agricultural products on a global scale, with an estimated annual production of around 904 million tons. Barley (Hordeum vulgare), a species within the Gramineae family, ranks as the fourth most important grain crop worldwide based on production. It is also the second most extensively cultivated cereal, covering 18% of the total cultivation area. This plant, which is currently at risk, demonstrates a considerable tolerance to non-living stresses. Abiotic stresses influence living organisms in diverse manners. In recent years, dust has emerged as a significant environmental challenge in western and southern Iran, leading to a reduction in soil moisture retention and negatively affecting plant health. Plants, due to their immobility, are particularly vulnerable to the adverse effects of air pollution compared to other organisms. Additionally, dust diminishes soil fertility, contributing to lower agricultural productivity and economic losses. The presence of dust on leaves further complicates these issues by obstructing light penetration, disrupting photosynthesis, reducing biomass production, and ultimately decreasing crop yields. This research seeks to analyze the impact of dust on the physiological characteristics of different barley genotypes.Materials and methodsThe research was conducted during the agricultural year 2022-2023 at the Faculty of Agriculture's research greenhouse at Ilam University. A factorial design was employed within a randomized complete block structure, incorporating three replications. The experimental factors included micro-dust treatments at two levels (with and without dust) and a selection of ten barley genotypes sourced from the IPK Institute's seed bank in Germany. To simulate dust stress, soil was collected from the Mehran region, sieved through 53-micron screens, and analyzed for physicochemical properties (refer to Table 2). A plastic chamber measuring 150 x 2.20 x 3.40 meters (length x width x height) was constructed to mimic conditions of a dust storm. Dust was applied during the seedling phase, and physiological traits such as leaf chlorophyll content, leaf soluble protein concentration, leaf proline content, and leaf soluble carbohydrates were evaluated ten days after the dust application. Following the assessment of these traits, variance analysis and mean comparisons were conducted using SAS 9.4 software, while graphs were generated using the GraphPad program. Mean comparisons were performed using the LSD (least significant difference) test at a 5% probability level, and correlation comparisons along with principal component analysis were executed using JMP software.Results and discussionThe results of this research highlighted the importance of the cultivar×dust interaction in influencing the levels of chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, ion leakage, relative water content (RWC), proline, catalase, and sugars, all at a significance level of 1%. In contrast, neither dust nor dust treatment showed a significant effect on protein content. Exposure to dust resulted in decreased levels of chlorophyll, ion leakage, relative water content, and protein, while it caused increases in proline, catalase, and soluble sugars. Correlation analysis revealed a positive relationship among photosynthetic pigments, whereas their association with relative water content was negative. Furthermore, a strong positive correlation (r = 1) was identified between protein and carbohydrates. Factor analysis conducted on the examined traits identified three factors with eigenvalues exceeding one, which collectively accounted for 99.72% of the total data variation. Notably, relative water content exhibited a significant positive correlation with protein (r=0.758) at the five percent significance level.ConclusionThe findings indicate that dust stress negatively impacted photosynthesis, ion leakage, relative water content, and protein levels, while simultaneously elevating carotenoids, proline, catalase, and soluble carbohydrates. The effects of dust stress varied across different cultivars, with certain traits in specific cultivars showing increased vulnerability. Remarkably, the HOR6964 genotype demonstrated a higher level of resilience in comparison to other genotypes.
Breeding plants for stress conditions
Parvaneh Gholizadeh Sarcheshmeh; Jalal Saba; Hassan Amirioghan; Farid Shekari; Amir Gholizadeh
Abstract
IntroductionToday, lack of water is one of the most important factors limiting crop growth in arid and semi-arid regions, and the reduction in growth caused by drought stress is far more than other environmental stresses. In order to investigate the relationships between yield and agronomic and phenological ...
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IntroductionToday, lack of water is one of the most important factors limiting crop growth in arid and semi-arid regions, and the reduction in growth caused by drought stress is far more than other environmental stresses. In order to investigate the relationships between yield and agronomic and phenological traits and to determine the relationships between these traits in spring rapeseed genotypes, seven rapeseed lines were crossed with five testers under two moisture conditions in the 2019-2020.Materials and methodsThe first generations hybrids along with 12 parents were evaluated under normal irrigation conditions and drought stress at the end of the season. Under normal irrigation conditions, irrigation was carried out in the stages of cultivation, rosette, stem growth, flowering, stem formation and grain development. Manual weeding was done to control weeds. In order to apply drought stress at the end of season, irrigation is stopped after flowering. The traits evaluated in this research included days to flowering, days to end of flowering, length of flowering period, days to physiological maturity, plant height, number of pods per plant, length of pods, number of grain per pods, height of the first pods from the ground, 1000 grain weight, grain yield per hectare, oil percentage, number of pods in the sub-branches, number of pods in the main stem, number of sub-branches, diameter of pods, length of the main stem, diameter of the stem at a height of 20 cm.Results and discussionThe correlation results of traits in normal irrigation conditions showed that grain yield had a positive and significant correlation with the traits of number of pods per plant, number of pods in sub-branches, stem diameter at a height of 20 cm, number of seeds in pod and number of sub-branches. Under drought stress at the end of the season, number of pods per plant, number of seeds per pod and diameter of pod had a positive and significant correlation with grain yield and day to flowering had a negative and significant correlation with grain yield. Based on the results of the stepwise regression analysis in both conditions, the number of pods per plant under normal irrigation conditions and drought stress justified most of the changes in the regression model. Based on the results of path analysis in both experiment conditions, number of pods per plant, thousand grain weight, number of grains per pod and the height of the first pod from the ground have direct positive effects and days to physiological maturity had direct negative effect on grain yield. Also, the length of the main stem under normal irrigation conditions and the number of pods in the sub-branches under drought stress conditions at the end of the season had direct negative effects on grain yield. However, all these negative direct effects were neutralized by positive indirect effects through other traits and caused the correlation coefficients of these traits with grain yield to become insignificant. In principle component analysis, in normal irrigation conditions, the total of 6 independent factors justifed about 75.9% of the changes, the first component including the number of pods in sub-branches, the number of pods per plant and the diameter of the stem at a height of 20 cm. In the conditions of drought stress at the end of the season, a total of 7 independent factors justified about 75.2% of the changes, the first factor consisting of the number of pods in the sub-stem, the number of pods per plant, the number of sub-branches, the diameter of the stem in the height of 20 cm.ConclusionIn general, in both conditions of normal irrigation and drought stress at the end of the season conditions, the number of pods per plant and the number of grains per pod had a high share of total changes and were the most effective traits on grain yield. Therefore, since these traits are more heritable than grain yield, selection to increase them can be recommended for indirect improvement of grain yield in breeding programs.
Salinity stress
Majid Rajaie; Sirus Tahmasebi; Manouchehr Dastfal
Abstract
IntroductionEnvironmental stresses are the most important factors reducing the yield of agricultural crops in the world. Salinity stress affects 20% of the worl’s arable lands, which increases day by day due to climate change and human activities. Wheat has great genetic diversity for salt tolerance. ...
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IntroductionEnvironmental stresses are the most important factors reducing the yield of agricultural crops in the world. Salinity stress affects 20% of the worl’s arable lands, which increases day by day due to climate change and human activities. Wheat has great genetic diversity for salt tolerance. Improvement and development of salinity tolerant cultivars is a suitable solution to reduce the negative effects of salinity. This research was conducted to investigate and determine the most tolerant varieties and promising lines of wheat to different levels of irrigation water salinity.Materials and methodsIn order to evaluate the response of bread wheat cultivars and lines to different levels of salt water and to determine the salinity tolerance indices, a factorial greenhouse experiment was conducted in a completely randomized design with three replications in the Agricultural and Natural Resources Research and Education Center of Fars province in 1399-1400 years. The light condition of the greenhouse was natural and its temperature was in balance with the outside environment. The experimental factors included wheat genotypes and different degrees of salt water. Wheat genotypes including commercial cultivars and some promising lines including Sistan, Narin, Brat, Sarang, Shush, Ayeneh, Sahar, Mehrgan, Ms-90-15, Ms-92-8, Ms-93-5, Ms-93-6, Ms-93-14, Ms-93-16 and S-94-12 were investigated. The salinity treatments tested with salinities lower and higher than the tolerance limit of wheat in values of 1, 10 and 16 dS m-1. Grain yield (g pot-1) and yield components including 1000 grain weight, number of fertile spikes per pot, number of grains per spike and biological yield (g pot-1) were recorded. Also, using the grain yield data, stress tolerance indices were calculated for medium and severe salt stress. Also, selection index of ideal genotype (SIIG) technique was used in order to investigate genetic diversity and integrate different indices into one selection index. Data variance analysis for different traits was done using SAS statistical software version 9.1. and mean comparison was done using Duncan's multi-range test at 5% probability level.Results and discussionMedium salt stress caused a decrease of 30, 26, 24, 26 and 20% in grain yield, biological yield, number of spikes per pot, number of grains per spike and 1000 seed weight of genotypes compared to control respectively. These reductions for severe salt stress were 53, 50, 42, 43 and 33% respectively. Mean comparison for the average of all cultivars in salinity levels showed that Sarang, Mehrgan, Brat, Sistan, Narin and S-94-12, without significant differences, had the highest biological yield, respectively. Also, for other yield components, the same genotypes along with Shush had the highest amount without significant difference. For grain yield, Sarang, Mehrgan, S-94-12, Barat, Shush, Narin and Sistan genotypes had the highest values. In the medium saline environment, S-94-12 and MS-92-8 lines had the lowest and highest percentage of grain yield reduction, respectively, compared to the non-saline environment. For severe salinity environment, the same reductions were observed in Mehrgan variety and MS-93-6 line. Based on the obtained results, the use of saline water of 10 ds/m decreased the grain yield of Sistan, Narin, Ms-90-15, Ms-92-8, Ms-93-5, Ms-93-6, and Ms-93-14, Ms-93-16, Brat, Sarang, Shush, Ayeneh, Sahar, Mehrgan and S-94-12 by 32.6, 36.2, 24, 40.5, 29.8, 32.5, 32.3, 26, 27.3, 30.5, 36.6, 21.7, 26.8, 30.2 and 15.6% respectively compared to non-saline irrigation water. These reduction values for 16 dS m-1 were 47.3, 56.3, 47.8, 50.6, 57, 65.4, 56.2, 50.2, 51.2, 50.5, 50.6, 46.6, 50.8, 47.3, 43.4 and 48.8%. Sodium content of leaves increased significantly with increase in salinity stress. The lowest sodium content with the amount of 0.257 and 0.259 percent was observed in Mehrgan and Sarang. Leaf potassium content in Sistan, Mehrgan, Brat, Sarang and S-94-12 showed a significant increase compared to other genotypes. Mehrgan and Sarang cultivars had the lowest ion leakage with the amount of 33.04 and 34.44%, respectively. The highest ion leakage was observed MS-93-6, MS-93-14, MS-93-5 and MS-93-16 lines. In order to increase the selection efficiency of superior genotypes, in addition to stress tolerance indices, the selection index of ideal genotype (SIIG) was used to integrate all stress tolerance indices into a single index. Investigation of the relationships between genotypes using the biplot analysis method and salinity tolerance indices showed that MP, GMP, HM and STI indices had a positive and significant correlation with yield in all levels of salinity.ConclusionThe results of the biplot analysis and the relatively high correlation between yield under normal and stress conditions showed that cultivars that have high yields under normal conditions will also show high yield under salinity stress conditions. Also, based on stress tolerance indices as well as SIIG selection index, Mehrgan, Sarang and Brat cultivars as well as promising line S-94-12 in greenhouse test conditions (under natural ambient light and temperature conditions), had better yield under saline conditions. The reason for this could be the greater adaptability of these cultivars to the climatic conditions of the introduced region compared to other investigated cultivars, including the cultivars introduced for saline conditions of other regions.
Drought stress
Esmaeil Fayaz; Ali Sorooshzadeh; Ali Heidarzadeh
Abstract
IntroductionRapeseed is one of the most important oilseed plants is cultivated in most regions of the world. Drought stress hurts the growth, development, and productivity of plants. and Canola, like many crops, is affected by this stress. Amino acids are one of the most important primary metabolites ...
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IntroductionRapeseed is one of the most important oilseed plants is cultivated in most regions of the world. Drought stress hurts the growth, development, and productivity of plants. and Canola, like many crops, is affected by this stress. Amino acids are one of the most important primary metabolites in plant cells that perform structural, metabolic and transport functions in plants, and many physicochemical characteristics of plant cells, tissues and organs are affected by the presence of amino acids. Considering the importance of oilseed rape cultivation in Iran in oil production and the problems of water scarcity at the end of the growing season of this plant, this research was conducted to study the oil rapeseed biochemical traits and oil yield change under amino acid foliar spraying and drought stress at the end of the season.Materials and methodsThis experiment was carried out as a factorial design based on randomized complete blocks in the research farm of the Faculty of Agriculture of Tarbiat Modares University, during the 1401-02 growing season. The experimental treatments include irrigation regimes at three levels (full irrigation, withholding irrigation from 50% flowering stage, withholding irrigation from pod forming) and foliar spraying at five levels (no foliar spraying, zero foliar spraying (distilled water), one, two and three grams of amino acids per liter). leaf area index (by DELTA-T DEVICES made in England) and greenness index (by SPAD) were measured one week after the last foliar spraying. Total chlorophyll, anthocyanin, flavonoid, proline, and phenol were measured based on fresh plant samples in laboratory according to the protocol. At maturity, biological yield, oil content and oil yield were measured. Statistical calculations of analysis of variance and mean comparisons were performed using SAS 9.4 software.Results and discussionThe results showed that the interaction of drought stress and foliar spraying significantly affected the percentage and yield of oil, total chlorophyll, anthocyanin, flavonoid, proline, total phenol, leaf area index, SPAD and biological performance. Drought stress caused a significant decrease in traits such as leaf area index, yield and oil percentage, biological yield and total chlorophyll content. However, foliar spraying of amino acids at different levels reduced the negative effect of drought stress on the investigated traits. The results showed that the interaction of drought stress and foliar spraying significantly affected leaf area index, SPAD, biological yield, oil percentage and yield, total chlorophyll, anthocyanin, flavonoid, proline and total phenol. The highest leaf area index (3.52), biological yield (25955 kg/ha) and oil content (43.3%) were achieved by full irrigation conditions and foliar spraying of two grams of amino acids per liter. Also, the highest amount of anthocyanin (0.093 µmol g-1FW), flavonoid (1.64 µmol g-1FW) and proline (238.2 µmol g-1FW) were obtained by foliar spraying two grams of amino acids per liter under withholding irrigation from the flowering stage. Also, applying two grams of amino acid per liter produced the highest yield of oil (1924.6 kg/ha).ConclusionAccording to the results of this research, the positive effect of foliar spraying of amino acids on biochemical traits and oil yield was obtained by foliar spraying of two grams of amino acids per liter in all three irrigation regimes (full irrigation, withholding irrigation from 50% flowering stage, withholding irrigation from pod forming). Therefore, foliar spraying of two grams of amino acid per liter is recommended to increase oil yield in oilseed rap cultivation.
Drought stress
Leila Akbari; Zeinab Chaghakaboodi
Abstract
IntroductionOne of the most significant global challenges is drought stress, which leads to a reduction in agricultural and horticultural crop yields and an increase in secondary metabolites. Zinc, as a mitigating factor against drought stress, plays a crucial role in this context. Chlorophyll fluorescence ...
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IntroductionOne of the most significant global challenges is drought stress, which leads to a reduction in agricultural and horticultural crop yields and an increase in secondary metabolites. Zinc, as a mitigating factor against drought stress, plays a crucial role in this context. Chlorophyll fluorescence parameters are essential for assessing the photosynthetic capacity throughout the plant's lifecycle. This study aimed to compare resistance to varying moisture levels, evaluate physiological indicators, and assess the functionality of photosystem II using chlorophyll fluorescence parameters and biochemical characteristics. Plant adaptation to drought is examined through various physiological, morphological, biochemical, and molecular responses and adjustments. Soluble sugars help prevent protein and cell membrane dehydration by maintaining osmotic pressure in plant leaves under drought stress conditions.Materials and methodsIn a factorial experiment with a completely randomized design, the first factor comprised three levels of drought stress (75%, 50%, and 25% of field capacity), while the second factor included three concentrations of zinc nitrate (0, 5, and 10 mg.l-1) applied to the Balangue (Lallemantia iberica) plant. The uppermost leaves of the plant were selected to determine the desired indices and were covered with special clamps for fifteen minutes. Subsequently, light was shone on the leaf for two seconds using a device, and the desired indicators were recorded. The aerial parts of the plants were harvested, dried, powdered, and soaked in ethanol and methanol at room temperature for 48 hours to assess biochemical characteristics. The concentration of methanolic and ethanolic extracts was performed using a rotary evaporator, and the samples were stored in a refrigerator.Results and discussionIn the results comparing the mean with increasing levels of drought stress and application of foliar spraying with nitrate, there was no decrease in Pi and Fv/Fm at different stress levels. The greatest effect of foliar spraying was related to the amount of ten milligrams per liter of zinc nitrate in the investigated levels. Also, at different levels of drought stress, foliar spraying using zinc nitrate caused a significant change in the amount of phenol (13.50 mg.l-1), soluble sugar (94.15 mg.l-1), and flavonoid (8.49 micrograms). per liter and anthocyanin content (0.138 μg.l-1).ConclusionThe results have shown that the application of moisture stress at the investigated levels significantly increased the content of biochemical traits (soluble sugar, total phenol, flavonoid content, and anthocyanin content) and chlorophyll fluorescence indices. Increasing the level of carbohydrates, especially sugars, plays an important role in protecting and regulating osmosis. Additionally, the accumulation of soluble sugar molecules stabilizes the structure of macromolecules and ultimately prevents the deformation and destruction of biological molecules. Therefore, the use of foliar spraying at two levels of five and ten milligrams of zinc nitrate during the stress period has shown a decrease in the level of these compounds. The highest difference was related to 50% moisture stress and the use of 10 mg.l-1 of zinc nitrate. The use of zinc oxide and green zinc nanoparticles in the soil and foliar application by spray significantly increases the absorption of nitrogen, phosphorus, potassium, and zinc and reduces the adverse effects of drought stress. Therefore, under the influence of different moisture regimes at various growth stages of the plant, it is possible to improve the growth of the plant and enhance the biochemical characteristics of the balangue plant under drought stress conditions by using foliar spraying.
Drought stress
Mohammad Valipour; Afrasyab Rahnama; Payman Hassibi; Ali Monsefi
Abstract
IntroductionArid and semi-arid regions of the world are primarily characterized by water scarcity, which limits agriculture mainly to irrigated land. Presently and in the future, irrigated farming systems will have to operate under conditions of water scarcity, which significantly impacts food production ...
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IntroductionArid and semi-arid regions of the world are primarily characterized by water scarcity, which limits agriculture mainly to irrigated land. Presently and in the future, irrigated farming systems will have to operate under conditions of water scarcity, which significantly impacts food production and threatens global food security. Deficit irrigation is an important strategy involving the application of limited irrigation during drought-sensitive phenological stages of a crop. Water restriction is targeted at drought-tolerant growth stages, particularly the vegetative stages and late stages of ripening. The response of plants to deficit irrigation-induced water stress varies with growth stages and stress intensity. Deficit irrigation can maximize crop water productivity without significant yield loss, and various deficit irrigation strategies have been developed to improve crop performance under water deficit conditions. However, it is crucial to develop crop management strategies aimed at enhancing crop sustainability in stressful environmental conditions. Therefore, our study aimed to investigate the influence of different irrigation regimes at various growth stages on the morphological characteristics, and oil and grain yield of oilseed flax genotypes.Materials and methodsThis experiment was carried out during the 2022-2023 growing season, using a split-plot arrangement in a randomized complete block design with three replications. The study site was located at the research farm of Shahid Chamran University of Ahvaz, Iran. The main plots consisted of four irrigation regimes: control (irrigation at 80%, 80%, 80%, and 80% of field capacity), mild water deficit (irrigation at 60%, 70%, 70%, and 60% of field capacity), moderate water deficit (irrigation at 60%, 60%, 60%, and 60% of field capacity) and severe water deficit (irrigation at 40%, 50%, 50%, and 40% of field capacity). The sub-plots consisted of four oilseed flax genotypes: Isfahan, Kerman, Indian and Hungarian. Deficit irrigation treatments were applied at stem elongation, branching, flowering, and seed-filling stages. The control treatment was watered with sufficient water (80% field capacity) until the end of the experiment.Results and discussionThere were significant differences among genotypes and irrigation regimes in most traits. Deficit irrigation depend on plant growth stage and stress severity led to a significant reduction in the number of capsule per plant, the number of grain per capsule, grain number per plant, grain weight per plant, 1000-grain weight, plant height, branch number, biomass yield, harvest index, and grain and oil yield. The grain yield of all genotypes significantly decreased under mild, moderate and severe water-deficit stresses by 34%, 39% and 49%, respectively, compared to the control. Similarly, the oil yield reduced by 35%, 40%, and 52%, respectively, compared to the control. There was genetic variation in grain yield between genotypes in response to water deficit. Grain yield was significantly reduced for all genotypes in response to severe water-deficit stress, with larger reductions in Indian and Hungarian genotypes (56 and 62%, respectively) than Isfahan and Kerman genotypes (with 46 and 32%, respectively). The Isfahan and Kerman genotypes with higher grain yield exhibited a higher oil yield.ConclusionDifferent irrigation regimes applied at various growth stages had different effects on the morphological traits and yield of oil seed flax genotypes. The developmental stage and severity of water deficiency played an important role in the genotype responses to deficit irrigation management. The moderate deficit regime led to a 37% and 29% decrease in grain yield of Isfahan and Kerman genotypes, respectively, while saving about 35% of available water. Therefore, this deficit irrigation regime is recommended as a suitable strategy to improve water productivity. Moreover, Isfahan and Kerman genotypes are recommended for cultivation in semi-arid regions due to their greater stability in grain yield under deficit irrigation conditions.
Drought stress
Hamid Esmaili Khanbehbin; Mohammad Reza Dadashi; Mohamad Taghi Feyzbakhsh; Fatemeh Sheikh; Ali Nakhzari Moghaddam
Abstract
IntroductionFaba bean (Vicia faba L.) is a rich source of phosphorus, calcium, iron, and protein and is very effective in rotation, cropping patterns, and in maintaining the sustainability of agricultural systems and fixing atmospheric nitrogen through symbiosis. Achieving figures with high performance ...
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IntroductionFaba bean (Vicia faba L.) is a rich source of phosphorus, calcium, iron, and protein and is very effective in rotation, cropping patterns, and in maintaining the sustainability of agricultural systems and fixing atmospheric nitrogen through symbiosis. Achieving figures with high performance and a wide range of adaptation to drought stress and climatic changes is one of the most important breeding goals in Faba bean (Vicia faba L). This study was conducted to evaluate the effects of drought stress on grain yield and some biochemical traits of new Faba bean lines.Materials and methodsThis experiment was carried out in the crop year of 2022-2023 in the form of a split-plot experiment in the form of randomized complete blocks design with 3 replications at the Gorgan Agricultural Research Station. In this study, 9 low tannin lines of Vicia faba L along with two control cultivars Mehta (low tannin) and Shadan (high tannin) were compared and evaluated in two environments of drought stress (after flowering) and normal irrigation. The lines studied in this experiment were selected and cultivated from the superior lines of the preliminary faba bean experiments. Each experimental unit was in four lines with a distance of 60 cm, a length of 6 m and a plant distance on the row of 8 cm. In the normal irrigation environment (without stress), the time required for irrigation was based on weather conditions and the water requirement of the plant (sowing, before flowering, the beginning of flowering and seed filling) in four irrigation times so that the plant does not face drought stress, but in the drought stress environment, no irrigation was done from the beginning of flowering to the end of the growing season.Results and discussionThe results of composite variance analysis (mean square) showed that the interaction between drought stress and variety on chlorophyll b, total chlorophyll, proline, soluble sugar, carotenoid, number of branches per plant and number of pods at a statistical level of 1% and on chlorophyll a and weight Seed dryness in the plant was significant at the five percent level. Comparison of the average interaction between drought stress and variety showed that Shadan variety and lines BPL4104, WRB1-3, FLIP03-07FB had the highest seed yield per hectare with 5100, 4950, 4750, 4633 kg respectively. Also, in the conditions of drought stress, FLIP03-07FB, WRB1-3 and Shadan varieties had the highest production of 500, 473 and 437 kg of seed yield per hectare, respectively. In the normal environment, Shadan variety had the highest amount of chlorophyll a, chlorophyll b, total chlorophyll and carotenoid at 1.53, 0.46, 0.2 and 0.58 mg g-1 respectively, and the line FLIP03-07FB with 9.47 μmol ml-2 had the most proline and line S2008,033 with the amount of 1.16 mg per gram had the most soluble sugar. The highest number of seeds per pod (3.28) was obtained in normal environment and the lowest number of seeds per pod (0.303) was obtained in drought stress environment. Identifying drought-resistant cultivars at the end of the season is one of the strategies for developing faba bean cultivation in the country. Drought stress during flowering and pod formation reduces the transport of photosynthetic materials, resulting in grain shrinkage, reduced grain weight, and reduced grain yield, while lack of stress during the flowering stage increases the length of the grain filling period, increases grain weight, and grain yield.ConclusionAccording to the results, it can be stated that drought stress in the flowering and seed filling stage caused a decrease in seed yield and an increase in carotenoid, proline and soluble sugar levels in all cultivars. Shadan variety and lines WRB1-3 and FLIP03-07FB had the highest seed yield in both environments. Therefore, the cultivation and development of two new lines are suggested after carrying out compatibility tests in different regions of the country and achieving the stability of seed yield.
Drought stress
Parisa Sheikhzadeh; Ali Narimanzadeh; Nasser Zare
Abstract
IntroductionDrought stress is considered an important abiotic stress, one of the factors affecting the production of crops and agricultural sustainability around the world, especially in arid and semiarid regions. Pinto bean (spotted bean) (Phaseolus vulgaris L.) is one of the major pulse crops in Iran. ...
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IntroductionDrought stress is considered an important abiotic stress, one of the factors affecting the production of crops and agricultural sustainability around the world, especially in arid and semiarid regions. Pinto bean (spotted bean) (Phaseolus vulgaris L.) is one of the major pulse crops in Iran. It is widely cultivated in arid and semiarid regions. The protein content of the pinto bean varied from 21.4% to 23.6%. Drought is a major limiter of yield in pinto beans, decreasing food security for those who rely on it as an important source of protein. Protecting plants from adverse environmental conditions by using simple methods could be of great value under these conditions. Salicylic acid (SA) is one of the important growth regulators that modulate plant responses to environmental stresses including drought stress.Materials and methodsA split plot experiment was conducted based on a randomized complete block design with three replications at the research farm in the East Azerbaijan province, Sarab, during 2019-2020. Factors experiment included irrigation at two levels (full irrigation as control, irrigation withholding in 50% of flowering stage) and foliar application of salicylic acid at three levels (foliar application with water as control, 100 and 200 mg.l-1). In this study, morphological traits, plant height, the number of sub-branches, the number of pods per plant, the weight of 100 grains, grain yield, and harvest index of pinto beans were investigated. Also, the measured traits included the chlorophyll index, malondialdehyde (MDA), hydrogen peroxide (H2O2), and Electrical Conductivity (EC).Results and discussionDrought stress reduces the value of all traits (chlorophyll index, plant height, the number of sub-branches, the number of pods per plant, the weight of 100 grains, grain yield and, harvest index) except MDA, EC and H2O2. However, salicylic acid foliar application was able to mitigate the adverse effects of water stress. Drought stress decreased chlorophyll index (about 14.2%), plant height (about 8.2%), number of sub-branches (about 22.9), the number of pods per plant (about 10.5%), the weight of 100 grains (about 8.9), grain yield (about 14.1) and harvest index (3.1%) and increase in the content of the MDA, EC and H2O2 (about 61, 2.1, and 92.2 present, respectively) as compared to the control treatment. Chlorophyll index, plant height, the number of sub-branches, the number of pods per plant, the weight of 100 grains, grain yield and harvest index in pinto bean were increased with the application of different concentrations of salicylic acid. Foliar spraying with 200 mg.l-1 salicylic acid caused a significant increase in the chlorophyll index, number of sub-branches, the number of pods per plant, (about 17.9, 33.02 and 18.4 present, respectively) and decreasing the MDA (about 49.33%) as compared to the control treatment. Under full irrigation and drought conditions, foliar spraying with 200 mg.l-1 salicylic acid caused a significant increase in the plant height (15.92 and 9.8%), the weight of 100 grains (17.8 and 12.8%), grain yield (27.3 and 20.4%) and harvest index (13.5 and 10.7%) and decrease in the content of the EC (1.7 and 2.3%) and H2O2 (28.9 and 81.9%), respectively.ConclusionIn this study, by exacerbation of water stress, all agronomic traits were reduced. Foliar spray of salicylic acid improved the pinto bean plant tolerance to drought stress by regulating several physiological responses. Salicylic acid treatments with the increase of content of the MDA, EC and H2O2, mitigated the negative effects of drought stress, thereby increasing tolerance and growth of the pinto bean plant. The results also showed that the concentration of 200 mg.l-1 salicylic acid improved plant growth and drought tolerance in pinto bean plant more effectively than the concentration of 100 mg.l-1 salicylic acid.
Physiology of crops under stress conditions
Mansoureh Tashakorizadeh; Pooran Golkar; Mohammad Reza Vahabi
Abstract
IntroductionCopper (Cu2+) is an essential element for the plant's metabolic processes, which is required by the plant for many enzymatic activities and playing a vital role in various physiological processes, growth, and development in small amounts. On the other hand, high concentrations of copper ...
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IntroductionCopper (Cu2+) is an essential element for the plant's metabolic processes, which is required by the plant for many enzymatic activities and playing a vital role in various physiological processes, growth, and development in small amounts. On the other hand, high concentrations of copper can be toxic to plants and high accumulation of this element in the soil prevents the elements needed for growth from reaching the aerial organs and prevents the normal growth of the plant. Drought stress also disrupts the growth and water relations in the plant and leads to a decrease in the efficiency of water consumption in the plant and causes a variety of physiological responses along with yield reduction. Soil contamination with heavy metals adversely affects plants growth, its development and metabolism in many parts of the world including arid and semi-arid regions. Multiple stresses caused a wide range of changes in plant physiology and metabolisms in plants. Fumaria parviflora Lam (Fumariaaceae) is an annual herbaceous medicinal plant with branched stems that is cultivated in arid and semi-arid regions of Iran.Materials and methodsThis study was conducted as a factorial experiment based in a completely randomized design in greenhouse conditions with three replications. In this study, the independent and combined effects of different concentrations of copper element (control, 50, 150, 300 and 400 mg kg-1) and different levels of drought stress (control, 50% and 75% based on soil moisture percentage discharge) was investigated on seed yield, malondialdehyde, soluble carbohydrates, proline, total anthocyanin content, total phenolics content, total flavonoids content, and antioxidant activity of Fumaria Parviflora Lam. The seeds of the plant were collected from two mining areas (Askari ravar and Rabor) from four zones (Z1, Z2, Z3 and Z4) in Kerman province.Results and discussionThe results of this study showed that the lowest amount of total phenoolics (89.3 mg GAE g-1 DW) and total flavonoids (8.1 mg QE g-1 DW) content was observed in the control treatment and the highest amounts for total phenolics (123.2 mg GAE g-1 DW) and total flavonoids (14.7 mgQE g-1 DW) were observed in severe drought stress. Here, the independent and combined effects of different concentrations of copper element and drought stress showed an increasing effect the biochemichal traits. The interaction effect of 50 mg kg-1 of copper on drought stress was decreasing in grain yield, proline and anthocyanin content. At a concentration of 150 mg kg-1, the copper element had an increasing effect on the drought stress for proline content, amount of soluble carbohydrates and anthocyanin content. The interaction effects of copper and drought stress showed that in concentrations of 300 and 400 mg kg-1, copper has an increasing effect in the presence of drought stress for proline, anthocyanin, total phenolics, total flavonoids, antioxidant activity and malondialdehyde content, but had a reducing effect on soluble carbohydrates.ConclusionThis study was studied by the first time on the combined effects of a heavy metal and drought stress on F. parviflora. Under moderate drought stress, F. parviflora Lam. was able to withstand the stress up to the concentration of 150 mg kg-1 of copper by using defense mechanisms. Also, the areas with high concentration of copper (Z3 and Z4) in the studied mining areas were more tolerant to high copper stress and showed higher grain yield than the areas with lower concentration of copper (Z1 and Z2). The findings confirmed the use of F. parviflora as a suitable species for soils contaminated with low to moderate copper (50-150 mg kg-1) under moderate drought stress. Based on these findings, it can be concluded that F. parviflora can deal with copper stress due to its active antioxidant defense system. It is possible to collect the seeds of this plant from areas with high concentration of copper (300 and 400 mg kg-1) for the cultivation of F. parviflora under contaminated areas with copper stress.
Heavy metals
Fatemeh Mahmoudi; Parisa Sheikhzadeh; Nasser Zare; Behrouz Esmailpour
Abstract
IntroductionConsidering that heavy metals are one of the most important environmental stresses in today's agricultural ecosystems, which lead to a decrease in germination, seedling growth, and ultimately plant production. Therefore, it is recommended to use several compounds such as an addition to the ...
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IntroductionConsidering that heavy metals are one of the most important environmental stresses in today's agricultural ecosystems, which lead to a decrease in germination, seedling growth, and ultimately plant production. Therefore, it is recommended to use several compounds such as an addition to the culture medium or seed priming to increase the tolerance of plants to environmental stresses. Considering the role of salicylic acid in reducing the effects of heavy metal stress, including cadmium, on germination and seedling growth, this research was conducted to investigate the effect of salicylic acid application methods on seed germination and biochemical characteristics of quinoa seedlings under cadmium stress.Materials and methodsTo investigate the effect of salicylic acid application methods on seed germination and biochemical characteristics of quinoa seedlings under cadmium stress, a factorial experiment based on completely randomized design (CRD) was conducted with four replications at University of Mohaghegh Ardabili. The treatments included the application methods of salicylic acid (seed priming and adding to the culture medium) and cadmium stress at five levels (0, 50, 100, 150, and 200 mg l-1). In this study, the measured traits include the germination percentage, germination rate, germination synchronicity index, mean daily germination (MDG), seedling length, and seedling dry weight, vigor index (VI), mean germination time (MGT), D50, the activity of catalase, peroxidase and polyphenol oxidase enzymes of quinoa seedlings were investigated. All tests were performed in 3 replications and the mean comparison was based Duncan's Multiple Range test at a 5% probability level. The statistical analysis was carried out using SAS 9.4 and Excel software. Results and discussionThe results of this research showed that the germination percentage, germination rate, germination synchronicity index, mean daily germination, seedling length, seedling dry weight and, vigor index decreased, and the mean germination time, D50, the activity of catalase, peroxidase and, polyphenol oxidase enzymes increased with the increasing cadmium concentration. Among the salicylic acid application methods (priming and adding to the culture medium), seed priming method had a greater effect on improving the germination percentage, germination rate, germination simultaneity index, mean daily germination, seedling length, seedling dry weight, and increasing vigor index, activity of catalase, peroxidase and polyphenol oxidase enzymes. Also, the mean germination time and D50 were reduced by seed priming methoed. Under cadmium stress, Both methods salicylic acid application, there was a significant increase in the activity of antioxidant enzymes in seedlings. Under 200 mg l-1 of cadmium concentration, seed priming with salicylic acid caused an increase in the catalase activity (11.27%), peroxidase activity by 6.51 to 9.69%, and polyphenol oxidase activity by 68.39%. ConclusionOverall, the results of this study showed that with increasing cadmium stress concentrations, the traits of germination percentage, germination rate, seedling length, seedling dry weight, germination synchrony index, mean daily germination, and vigor index decreased, while the traits of mean germination time, time to 50% germination, and the activities of catalase, peroxidase, and polyphenol oxidase enzymes increased. Cadmium stress causes ionic imbalance that stimulates the production of reactive oxygen species (ROS), which leads to disruption of cell membranes, osmotic regulation, and the production of secondary metabolites. Considering the negative effect of this stress on germination and growth of the obtained seedlings, among the application methods (priming and adding to the culture medium), seed priming had a greater effect on improving germination, seedling growth and increasing the quinoa seed vigor index, as well as increasing the activity of antioxidant enzymes compared to the method of adding salicylic acid to the planting medium. Priming of quinoa seeds with salicylic acid by shortening the necessary germination time causes primed seeds to germinate faster than control seeds under normal and cadmium-stressed conditions, and by reducing the mean germination time and D50, it reduces cadmium damage and protects the germination process against the toxicity of this heavy metal.
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