Drought stress
Raouf Seyed Sharifi; Reza Seyed Sharifi; Razieh Khalilzadeh
Abstract
IntroductionDrought stress is the most influential factors affecting crop yield particularly in irrigated agriculture in arid and semiarid regions. This stress induces various biochemical and physiological responses in plants as a survival mechanism (Tas and Tas, 2007). Drought stress have a direct impact ...
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IntroductionDrought stress is the most influential factors affecting crop yield particularly in irrigated agriculture in arid and semiarid regions. This stress induces various biochemical and physiological responses in plants as a survival mechanism (Tas and Tas, 2007). Drought stress have a direct impact on the photosynthetic apparatus, essentially by disrupting all major components of photosynthesis including the thylakoid electron transport, the carbon reduction cycle and the stomatal control of the CO2 supply, together with an increased accumulation of carbohydrates, peroxidative destruction of lipids and disturbance of water balance (Allen and Ort, 2001). It breaks down the balance between the productions of reactive oxygen species (ROS) and the antioxidant defense system causing the accumulation of ROS which induces oxidative stress to protein, membrane lipids and disruption of DNA strands (El Tayeb, 2006). Several strategies have been developed in order to decrease the toxic effects caused by severe water limitation on plant growth. Among them the use of vermicompost and nano silicon play a key role in yield improvement. The aim of this study was to investigate the effects of vermicompost and nano silicon application on yield and some physiological and biochemical traits of safflower under irrigation withholding conditon.Materials and methodsIn order to study the effect of vermicompost and nano silicon on yield and some physiological and biochemical traits of safflower (Carthamus tinctories L.) under irrigation withholding conditon, an experiment was conducted as factorial based on randomized complete block design with three replications in research farm of University of Mohaghegh Ardabili during 2019-2020. Factors experiment were included irrigation levels (full irrigation as control, irrigation withholding in 50% of heading bud and flowering stages as severe and moderate water limitation respectively) according with 55 and 65 BBCH code, foliar application nano silicon (foliar application with water as control, application of 25 and 50 mg.l-1 nano silicon) and application of vermicompost (no application of vermicompost as control, application of 4 and 8 t.ha-1). Vermicompost was purchased from the Gilda corporation. The safflower cultivar "Padideh" was used in the experiment with plant density of 40 seeds m-2. Chlorophyll and carotenoids were obtained based on method of Arnon (1967). The quantum yield was measured by the uppermost fool expanded leaf using a fluorometer (chlorophyll fluorometer; Optic Science-OS-30 USA). For this purpose, the plants adapted to darkness for 20 minutes by using one special clamp then the fluorescence amounts were measured in 1000 (µM photon m2s), and calculation was performed using following formula (Arnon, 1967):ØPSII = (Fm-F0)/Fm ØPSII; quantum yield amount of photosystem II, Fm or maximum fluorescence after a saturated light pulse on plants adapted to darkness and F0, the minimal fluorescence in the light adapted, which was determined by illumination with far-red light. To measure the enzyme activity, 0.2 g of fresh tissue was crushed by using liquid nitrogen and then one ml of buffer Tris-HCl (0.05 M, pH=7.5) was added. Obtained mixture centrifuged for 20 min (13000 rpm and 4 ºC), then supernatant was used for enzyme activity measurements. Catalase, Peroxidase and Polyphenol Oxidase activity was assayed according to Karo and Mishra (1976). Also, the evaluation of protein carried out by Bradford (1976) method, 0.2 g of plant tissue was squashed with 0.6 ml extraction buffer and was centrifuged at 11500 rpm for 20 minutes at 4 °C. The supernatant was transferred to the new tubes and centrifuged for 20 minutes at 4000 rpm. To measure the protein amount, 10 µl of obtained extract was added to 5 µl Bradford solution and 290 µl extraction buffer and the absorbance rate was read at 595 nm.Statistical analysis: Analysis of variance and mean comparisons were performed using SAS ver 9.1 computer software packages. The main effects and interactions were tested using the least significant difference (LSD) test at the 0.05 probability level.Results and discussionThe results showed that application of the highest nano silicon level under full irrigation increased chlorophyll a and chlorophyll b (74 and 145% respectively) in comparison with no application of nano silicon under irrigation withholding in heading bud stage. Means comparison showed that irrigation withholding in booting bud at the highest vermicompost level increased proline and soluble sugars content (149 and 99% respectively) and antioxidant enzymes activity such as catalase, peroxidase and polyphenol Oxidase (103, 82 and 94% respectively) in comparison with no application of vermicompost under full irrigation. Also, the highest vermicompost level under full irrigation increased chlorophyll a, quantum yield and grain yield (61, 62 and 119% respectively) in comparison with no application of vemicompost under irrigation withholding in heading bud stage.ConclusionIt seems that the application of vermicompost and nano silicon can increase grain yield of safflower under water limitation conditions due to improving physiological and biochemical traits.
Drought stress
Mohamad Forouzandeh; Soheil Parsa; Sohrab Mahmoodi; Ali Izanloo
Abstract
IntroductionThe use of new agricultural technologies such as bio-elicitors is a valuable approach to reduce effects of drought stress. The present study investigated the prospects of enhancing yield and some physiological properties in quinoa under different levels of plant water requirement using elicitors, ...
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IntroductionThe use of new agricultural technologies such as bio-elicitors is a valuable approach to reduce effects of drought stress. The present study investigated the prospects of enhancing yield and some physiological properties in quinoa under different levels of plant water requirement using elicitors, such as methyl jasmonate (MeJA) and salicylic acid (SA) elicitors. Materials and methodsThe aim of this study was to evaluate comparative effect of elicitors MeJA and SA foliar application on the yield and yield component of quinoa under drought stress. This experiment was conducted during 2020-21 cropping season as split plots in a randomized complete block design with three replications at research farm of Zabol University, Iran. The main plots was irrigation regimes at three levels: 100, 75, and 50 percent of crop water requirement and sub-plots of foliar spraying in six levels including: Control (sprayed with distilled water), 70% ethanol, 0.5 mM SA, 0.5 mM MeJA, 1 mM SA and 1 mM MeJA. In this study fertile branches per plant, sterile branches per plant, panicle numbers per m2, seed numbers per panicle, 1000 seeds weight, leaf relative water content, chlorophyll index (SPAD) and seed yield were measured. Determination of irrigation cycle and crop water requirement was based on CROPWAT 8.0 software and Penman-Mantis equation. For plant coefficients used FAO default data. Irrigation planning was determined with 85% efficiency and water volume of each plot calculated using a digital water meter. Results and discussionThe physiological response of the plants in terms of relative water content (RWC) was improved by 100 and 75 percent of crop water requirement conditions. The relative water content of the leaves decreased significantly under the influence of drought stress, although there was no significant difference between the control treatment and the supply of 75% of the water requirement of the plant, by increasing the stress intensity to 50% of the water requirement of the plant, a decrease of 31.6% in the relative water content of the leaves was observed. Additionally, doubling the elicitors concentration increased the yield and non-yield traits. Foliar application of MeJA and SA significantly increased the seed yield and fertile branches and sterile branches per plant, panicle number per m2, seed number per panicle and chlorophyll index treats. The use of 1 mM SA gave the best response after MeJA. Despite providing 50% of the plant's water needs, plants treated with 1 mM methyl jasmonate produced 45% more fertile shoots than plants sprayed with distilled water. Drought stress increased the number of infertile shoots by 77% compared to control plants. Increasing the intensity of drought stress and decreasing water availability decreased the filling rate and ultimately the seed weight. The application of 1 mM concentration of methyl jasmonate and salicylic acid increased the chlorophyll index compared to the control. Based on the results of comparing the averages, the highest level of this trait (46.84) was observed in the concentration of 1 mM methyl jasmonate. The positive effect of methyl jasmonate on the chlorophyll concentration of leaves may be due to the increase in the number and size of chloroplasts. The results showed that the interaction of irrigation and foliar application had a significant effect on all traits except 1000 seeds weight, RWC and chlorophyll index. The highest seed yield (2929.3 kg ha-1) was obtained from 100 percent of crop water requirement (4662 m3 ha-1) with 1 mM MeJA treatment.ConclusionsOur results showed that impaired water supply of quinoa with significant loss of relative water content endangers cellular health and reduced yield. In general, it can be said that, to achieve maximum yield of quinoa it is possible to use 100% of crop water requirement with 1 mM MeJA foliar application.
Drought stress
Younes Mir; Hamed Khosravi; Mashalah Daneshvar; Ahmad Ismaili
Abstract
Introductioncanola (Brassica napus L.) is one of the most important oilseed plants that has been ranked third in the oil production after soybeans and oil palm. Drought is seriously the most important factor limiting the growth and production of canola in Iran. By foliar application of micronutrients, ...
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Introductioncanola (Brassica napus L.) is one of the most important oilseed plants that has been ranked third in the oil production after soybeans and oil palm. Drought is seriously the most important factor limiting the growth and production of canola in Iran. By foliar application of micronutrients, plant growth condition can be improved under stress. Salicylic acid (SA) plays an important role in abiotic stress tolerance, and more interests have been focused on SA due to its ability to induce a protective effect on plants under adverse environmental conditions. It is necessary to know the traits related to drought tolerance and their relationship with Seed yield. Due to the important role of roots in the absorption and conduction of water and nutrients, accurate knowledge of the root system and how it is distributed in the soil is of particular importance. therefore, the purpose of the present study was to investigate the Effect of foliar application of micronutrients and salicylic acid to improve some quality traits and yield of canola (Brassica napus L.) under water deficit stress.Materials and methodsthe experiment was conducted as split factorial in a randomized complete block design with three replications at Lorestan University College of Agriculture, Iran during 2017-2018. Water deficit was considered as the main factor in levels irrigation at 80 (control) and 30% of field capacity, and in the subplots subtractive treatment of the two factors of foliar application of micronutrient elements (non-consumption and spraying at a concentration of 0.2%) and salicylic acid concentration of 0, 0.5, 1 and 1.5 mM). The time of water deficit stress coincided with the stage of the beginning of regrowth (BBCH32). foliar application of micronutrient fertilizer in rosette stage (BBCH29) and foliar application of salicylic acid in two stage of flowering beginning (BBCH60) and pod filling (BBCH72). the measured traits included Chlorophyll Total, Carotenoids, Photosynthesis rate, Transpiration rate, seed yield, oil percentage, and Protein percentage. the data was analyzed by statistical analysis system (SAS version: 9.1). the means were analyzed using the Duncan test at P=0.05.Results and discussionThe results of analysis of variance showed that the triple interaction of stress in micronutrient fertilizer and salicylic acid on all traits studied in this experiment were significant.The results of comparing the mean of the data showed that water deficit stress significantly reduced total chlorophyll (14%), carotenoids (21%), photosynthesis rate (19%), transpiration rate (53%), grain yield (27%), oil percentage (11%) and significantly increased protein content Seeds (22%). the combination (no stress + 1.5 mM salicylic acid spraying and concentration of 2 per thousand fertilizers Micronutrients) was obtained. produced the highest total chlorophyll (2.23 mg g-1 wet weight), transpiration rate (3.12 mmol H2O2 m-2 s-1), seed yield (4955.7 kg ha-1) and oil percentage (45.7). foliar application of micronutrient fertilizer and 1.5 mM of salicylic acid significantly increased total chlorophyll (34%), carotenoids (29%), photosynthesis rate (27%) and Seed yield (36%) compared to the control treatment (without application of micronutrient fertilizer and Salicylic acid).ConclusionA triple micronutrient fertilizer (iron+zinc+ manganese) with a concentration of 0.2% is recommended along with a concentration of 1.5 mM of salicylic acid to reduce the negative effects of water deficit stress and achieving acceptable seed yield.
Biotechnology and environmental stresses
Masoud Fakhrfeshani; Farajollah Shahriari Ahmadi; Mohammad Zare Mehrjerdi; Fatemeh Keykha Akhar
Abstract
IntroductionAmong abiotic stresses, Salinity has been increasing over the time for many reasons like using of chemical fertilizers, global warming and rising sea levels. In deed salinity stress and high concentration of ions are of the most determinative factors that simultaneously affect genetical, ...
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IntroductionAmong abiotic stresses, Salinity has been increasing over the time for many reasons like using of chemical fertilizers, global warming and rising sea levels. In deed salinity stress and high concentration of ions are of the most determinative factors that simultaneously affect genetical, biochemical and physiological processes of a plant. Some of plants known as halophytes have developed mechanisms that help them to avoid or tolerate the saline conditions. With the aim of understanding the probable mechanisms of saline tolerance in Aeluropus littoralis (as a halophyte) and the saline susceptibility of Oriza sativa var. IR64 (as a glycophyte), In the present study, the similarity of Cu/Zn Superoxide Dismutase (Cu/Zn SOD) gene sequences, the differential biochemical indexes such as aromatic and instability indices of them were evaluated in silico, based on amino acid composition of their Cu/Zn SOD. the gene expression pattern and fluctuation of Cu/Zn SOD as a ROS scavenger (in root and shoot) was also assessed and compared in a span of exposer time to stress and different salt concentratioMaterials and methodsThe seeds of A. littoralis and O. sativa var IR64 were prepared from Center for Research of Agricultural Science and Natural Resources (CRASN) which were sown in sand as a primary culture medium, after surface sterilization. After 21 days, the seedlings that had grown uniformly were transferred to continuously aerated hydroponic pots containing Yoshida nutrient solution. we established a stress span containing short term (6 hours), mid-term (24 and 48 hours) and long term (6 and 11 days) exposure to salinity stress. the gene expression pattern and fluctuation of Cu/Zn SOD as a ROS scavenger in Aeluropus, was evaluated at the sampling points of 6 h/100 mM, 6 h/200 mM, 6 h/300 mM, 48 h/300 mM, 144 h/300 mM and 264 h/300 mM. the elite sampling timepoint of rice, were also 6 h/30 mM, 6 h/60 mM, 6 h/100 mM, 48 hours/100mM, 144 hours/100 mM and 264 hours/100 mM. To study the structure of genes, genomic DNAs of A. littoralis and Oryza sativa L. Var IR64 were isolated from their leaf. Amplification of Cu/Zn SOD genes was performed with specific primers designed based on NCBI sequences. Amplification of their the maximum length fragments was carried out using a hot start, high fidelity DNA polymerase. The extracted fragments were cloned using pTZ57R vector in Escherichia coli (DH5α strain) and sequenced paired-end. The results were analyzed using NCBI database, and the biochemical features related to their proteins, such as isoelectric points, calculated weight, instability and aromatic indices, were analyzed Insilco using CLC Genomics Workbench 12 and Geneious Prime 2019.Results and discussionComparison of the real time quantitative PCR of Cu/Zn SOD transcriptome in roots showed that Aeluropus increase the expression of these genes faster and keeps their expression in long-term while rice loses them significantly. The increased expression of Cu/Zn SOD in the roots of Aeluropus maintained but its expression in rice down regulated. rice did not show any statistically significant changes in compare to control samples and persisted in this manner until the end of investigation. But in Aeluropus, the expression showed another increase after 264 hours of being in 300mM. In the shoots of Aeluropus, the level of Cu/Zn SOD expression increased gradually and reached its highest level after 48 hours commencement of 300 mM salinity stress. While shoots of IR64 Rice did not show any statistically different expression except a very late response at 144th hour of being in 100 mM salinity stress that was only about 40 percent higher than its counterpart control samples. Analysis of amino acid sequences' indices showed that Cu/Zn SOD of Aeluropus would have a superior stability and higher aromatic value in contrast to IR64 counterpart. These indices originate from the arrangement of amino acids which they themselves are the result of nucleotide arrangement in genome.ConclusionThe early and highly expression of Aeluropus Cu/Zn SOD gene studied in our experiment and their permanency and lasting of their activity in high concentration of salinity makes the sequence of it and its regulatory elements as a prospective candidate for future applied studies and transforming and improving salinity tolerance in many Poacea crops.
Biotechnology and environmental stresses
Abbas Saidi; Zahra Hajibarat
Abstract
IntroductionPotato is the one of the important crop in the world. This plant in terms of consumption rate in the world levels is after rice and wheat. Thus, this crop is considered the maintain food security. However, potato influences the abiotic stress particularly drought and cold. The C-repeat binding ...
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IntroductionPotato is the one of the important crop in the world. This plant in terms of consumption rate in the world levels is after rice and wheat. Thus, this crop is considered the maintain food security. However, potato influences the abiotic stress particularly drought and cold. The C-repeat binding factors (CBFs), also termed dehydration-responsive element-binding protein 1 (DREB1) family members, play crucial roles in the acquisition of stress tolerance, but in potato, the underlying mechanisms of stress tolerance remain elusive. The cold and drought stresses are the most abiotic stresses across the world causing to decrease of the crop yield. To gain insight into these mechanisms, CBF1 gene was selected from four potato and was assessed their expression under drought and cold stress conditions.Materials and methodsIn order to investigate the effect of cold and drought on growth and development on potato, a experiment was conducted at the the Seed and Plant Improvement Institute located at Karaj, Iran. The experimental design used was randomized complete block design with three replications under drought and cold stress (normal and stressed). Gene expression of CBF1 gene was performed in different tissues (root, stem, leaves, and tuber) under control condiotin. Further, analysis of expression in root and leaves under stress condition. After 3 weeks after cultivated in Karaj, the water stress was induced by irrigation suppression in 2 weeks. sampling was performed 5 weeks after sprouting under drought. Under cold stress, analysis of expression in root and leaves was performed at the 24h and 48h after 3 weeks of sprouting. CBF1 gene was selected as one of important gene in the investigation of molecular mechanism under cold and heat stress in potato.Results and discussionAverage induced expression in response to cold suggested a correlation between potato CBF1 expression and the acquisition of cold tolerance in root. Whereas, the expression of this gene was decreased in leaves. Under drought stress, the expression of CBF1 gene was up-regulated in root. However, the expression rate of CBF1 decreased under stress. Responses that varied between sections may reflect tissue-specific stress tolerance mechanisms, suggesting an effect of ecological context on the development of CBF1 mediated stress tolerance in potato. In this study, the investigation of transcription factor binding sites, co-expressed genes, and gene ontology of CBF1 in potato was performed. This gene is involved in multiple biological processes and pathways. The analysis of promoter showed that CBF1 gene had the highest and the lowest number of the TFBS in MYB and WRKY, respectively. The present study revealed that the CBF1 gene expression in root was the higher than leaves.ConclusionOverall, it can be concluded that CBF1 gene can contribute to cold and drought tolerance in potato and can be used for genetic and breeding manipulation to improve tolerance to stress.
Hawre Kiami; Shiva Khalesro; Zahed Sharifi; Ali Mokhtassi-Bidgoli
Abstract
IntroductionClimate change accelerated the negative effects on plant production; Therefore, agricultural researchers are focused on identifying strategies that minimize the effects of climate change on crop production. Black cumin (Nigella sativa L.) is an annual herbal plant belonging to the Ranunculaceae ...
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IntroductionClimate change accelerated the negative effects on plant production; Therefore, agricultural researchers are focused on identifying strategies that minimize the effects of climate change on crop production. Black cumin (Nigella sativa L.) is an annual herbal plant belonging to the Ranunculaceae family. It has been used in traditional medicine in the past. Black cumin has a lot of industrial and medicinal uses. Nowadays, regarding the importance of medicinal and aromatic plants, such as black cumin, different strategies should be applied to improve their traits in different conditions. Drought stress is an effective climatic factor. Biochar as an ecological input is introduced in recent years. It was hypothesized that biochar may alleviate drought effects. Accordingly, the aim of this study was to investigate the effect of biochar on morphological characteristics, physiological parameters activity, and yield of black cumin affected by drought stress.Materials and methodsTo evaluate the effect of biochar and different irrigation levels on the morpho-physiological traits of black cumin an experiment was carried out in the greenhouse of the University of Kurdistan in 2018. The experimental factors included three irrigation levels (100%, 70%, and 40% of the field capacity of the soil) and two biochar consumption levels (0, and 15 t ha-1). The experimental design was a factorial based on a completely randomized with three replications. The amounts of field capacity and permanent wilting point were separately calculated for two different levels of biochar. Fourteen seeds of black cumin were sown in each pot. All of the pots were irrigated after sowing. The morpho-physiological traits included relative water content, total chlorophyll, photosystem II efficiency, plant height, flowering and secondary branches number per plant, capsule and seed number per plant, and biological and grain yield were measured. The statistical SAS software (version 9.3; SAS Institute; USA) was used for ANOVA. The mean of treatments was compared with the LSD test.Results and discussionThe results showed that irrigation and biochar interaction had a significant effect on the morpho-physiological characteristics and yield of black cumin. Biochar application decreased the negative effects of drought stress. The greatest RWC (86.13) belonged to 100% irrigation and biochar application. Given the increased weights of pots containing biochar and increasing the leaf water potential, it can be concluded that biochar application ultimately increased RWC due to increasing water holding capacity. At the 40, 70, and 100% irrigation levels, biochar increased total chlorophyll by 1.43, 13.64, and 5.31% compared with non-application of biochar, respectively. The maximum (83.2%) and minimum (70.72%) photosystem II efficiency were observed in 100% irrigation with biochar and 40% irrigation and non-application of biochar, respectively. Biochar application enhances chlorophyll content consequently increasing photosynthesis compared with no biochar application under drought stress. The highest number of flowering and secondary branches per plant was obtained from 100% irrigation and biochar application and the lowest number of mentioned traits belonged to 40% irrigation and non-application of biochar. Drought stress reduced capsule number per plant. The minimum number of capsules was obtained from 40% irrigation level. Biochar increased capsule number per plant and seed number per plant at 70% and 100% of irrigation levels and 40% and 70% of irrigation levels, respectively. The greatest biological yield belonged to 100% irrigation and biochar application. This treatment increased biological yield due to enhancing morphological traits and yield components. At the 40, 70, and 100% irrigation levels, biochar increased grain yield by 33.51, 34.12, and 10.72% compared with non-application of biochar, respectively.ConclusionThe usage of biochar improved the relative leaf water content, total chlorophyll content, photosystem II efficiency, morphological traits, biological and grain yield of black cumin under drought stress. Overall it can be said that biochar not only can reduce the negative impacts of drought stress but only improve the growth of black cumin. Therefore, biochar can be used as a useful input in sustainable agricultural systems under drought stress.
Salinity stress
Mostafa Zangoie; Soheil Parsa; Majid Jami Al-Ahmadi; Ali Izanloo
Abstract
IntroductionCamelthorn is a perennial plant belonging to fabaceae family. Camelthorn tolerance to salinity is very high and it’s a halophyte plant. By using halophyte plants as species with potential for production in saline lands, many outturns can be produced in these areas, one of these products ...
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IntroductionCamelthorn is a perennial plant belonging to fabaceae family. Camelthorn tolerance to salinity is very high and it’s a halophyte plant. By using halophyte plants as species with potential for production in saline lands, many outturns can be produced in these areas, one of these products is fodder needed by livestock. Salinity and plant density are factors affecting forage quality. Increased salinity created by sodium chloride leads to an increase in sodium ions in the plant and affects the balance of sodium to potassium ratio and forage quality. Different plant ecotypes and genotypes absorb different amounts of elements in their culture medium. Considering that one of the most important areas for the development of cultivation of this plant is saline lands, which have been excluded from cultivation due to irrigation with saline water for many years with increasing soil salinity, It is necessary to study the nutrients changes in plant organs, which is one of the factors affecting forage quality in field conditions with irrigation with salt water. This study investigates the effect of irrigation water salinity in two ecotypes and different densities on the forage yield accumulation of nutrients in shoot and roots in field conditions in two locations.Materials and methodsThe experiment was conducted as a split factorial in a randomized complete block design with three replications. The experiment was analyzed in two separate locations. Experimental sites included the farm of the Faculty of Agriculture of Birjand University and the Hojjatabad farm of Peyvande Khavaran agro-industry located in Sarbishe. The experiment was conducted in 1399. Experimental Factors include ecotypes at two levels: Krond and Voshmgir, Irrigation water salinity at 3 levels of 3.5, 7.5 and 12 dS.m-1 and plant density at two levels were 10 and 20 plants per square meter. The main plots were considered as salinity levels and the sub-plots were considered as a combination of density and ecotype levels. Sampling was performed to measurement the nutrients of shoots and roots of camelthorn in mid-October. Shoot sodium, potassium, calcium and magnesium were measured at the end of the growing season.Results and discussionThe results showed that there is a negative relationship between the salinity and the forage yield. Application of maximum salinity level compare to the control reduced the forage fresh yield from 2825 to 1868 in Birjand and from 2425 to 1931 kg.ha-1 in Sarbishe. The increase salinity caused a significant increase in shoot sodium in Sarbishe from 1.39 to 2.68 percentages and root sodium in Birjand from 0.126 to 0.159 percentages and a significant decrease in root potassium in Sarbishe from 3.94 to 1.78 percentage of the plant dry matter. With the increase of plant density, the magnesium of aerial parts decreased from 0.023 to 0.016 percentages in Birjand and from 0.028 to 0.02 percentages of the plant dry matter in Sarbishe. Also, root magnesium decreased significantly in Birjand (from 0.015 to 0.011%) and root potassium decreased from 5.6 to 4.8 percentages in Sarbishe, but Shoot sodium increased significantly in both places. The effect of ecotype was significant on shoot sodium and magnesium in Birjand, shoot and root potassium and root magnesium in Sarbishe.The Krond ecotype had less potassium in Sarbishe than the Voshmgir ecotype statistically significant, so it had higher forage quality. Forage produced in Sarbishe had less potassium than Birjand, so it was of higher quality.ConclusionAlthough the increase in salinity caused a decrease in the camelthorn forage yield. However, this plant had an acceptable yield in high soil salinity at the end of the season. Therefore, it is possible to produce forage in very salty lands through the cultivation of this plant. Magnesium levels of camelthorn shoot were less than the required level of livestock and supplementary feeding should be considered to meet the need for magnesium and prevent complications of magnesium deficiency in long-term feeding of camelthorn forage. The shoot potassium is higher than the critical level for livestock and in case of long-term feeding; it should be consumed in combination with low-potassium fodder. Also, due to the higher shoot potassium of Voshmgir ecotype in Sarbishe, the use of Krond ecotype is recommended because of the lower potassium level. Shoot potassium level in Sarbishe was lower than Birjand (9 in Sarbishe and 12% in Birjand), so forage produced in Sarbishe was more desirable. The shoot sodium and calcium levels are optimal and there is no need to supplementary nutrition the livestock to provide these elements. Although increased salinity increased shoot sodium, it had no effect on potassium (only root potassium in Sarbishe decreased with increasing salinity), therefore, in salinity conditions, camelthorn can maintain the potassium level of its shoots and this feature is one of the factors affecting the plant's tolerance to salinity. Increasing sodium concentration was associated with decreasing root potassium concentration, indicating competition of sodium with potassium for uptake. Also, higher sodium concentration of shoots than roots can be considered as an effective factor in salinity tolerance by increasing the gradient of osmotic potential from roots to shoots.AcknowledgmentsThe authors consider it necessary for the sincere cooperation of Peyvande Khavaran agro-industry, especially the then formerly managing director of Sina Sarhadi, the production manager of Yahaghi and the manager of Hojjatabad farm, Abdollahi, as well as the laboratories of Animal Nutrition and Soil Science laboratories of Ms. Khairiyeh. Ms. Parsa and the farm officials of the Faculty of Agriculture, University of Birjand, who helped us in this research, would be very grateful.
Salinity stress
Samar Khayamim; Hamid Noshad; Mohsen Aghaeezadeh
Abstract
IntroductionGreen house studying especially for salinity stress needs suitable medium. It is necessary to determine suitable medium in greenhouse studies for screening germplasm, which is easily available, stable in terms of electrical conductivity and cost-effective. Soil, and Perlite are common mediums ...
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IntroductionGreen house studying especially for salinity stress needs suitable medium. It is necessary to determine suitable medium in greenhouse studies for screening germplasm, which is easily available, stable in terms of electrical conductivity and cost-effective. Soil, and Perlite are common mediums which are used in green house researches generally, but there weren’t enough reports for study hydroponic system for screening sugar beet germplasm. Drought and salinity stress happens at the same time in most regions of Iran and because of similar tolerance mechanisms for these stresses, drought tolerant germplasm could be used in screening for salinity.so the goal of this project was to evaluate different medium especially hydroponic to screening sugar beet drought tolerance genotype in salinity stress.Materials and methodsThe project was conducted in two experiments: (a) A factorial experiment based on completely randomized design with four replications was conducted in SBSI research greenhouse. The first factor was three planting media in combination with nutrition solution as follows: 1) loamy soil with about 5% organic matter, 2) perlite with Hoagland solution, 3) hydroponic environment with Hoagland solution. The second factor consisted of two levels of salinity including normal and salinity (16 dS m-1) treatments and the third factor consisted of two sensitive and tolerant genotypes. (b) 17 selected genotypes were investigated in greenhouse with perlite medium under control and salinity 16 dS m-1 in factorial experiment based on completely randomized design with four replications. Different quantitative and qualitative traits such as root. Shoot and total dry weights, K/Na, Soluble carbohydrates, glycine betaine were measured in both experiments and statistical analysis were done by MSTATC and SPSS and mean were compared in Duncan multiple range test at (α=0.05).Results and discussionCross effects of medium and salinity were significant on total and shoot dry weights, P, K/Na. Cross effects of medium, salinity and genotypes were significant on most of the traits. Crop yields under salinity stress were less in soil in comparison to other mediums, also salinity had significant effect on soil EC and Na (P≤0.01), soil and perlite were salinized respectively 6 and 2 times in comparison to normal condition. Which shows that soil is not stable medium for salinity study in green house. The highest yield (3.31 g p-1) was obtained from hydroponic. Yields achieved from hydroponic and perlite mediums were similar under salinity, but water consumption was more in hydroponic than perlite. In establishment stage, the total dry weight, soluble carbohydrates, glycine betaine and K/Na ratio were suitable for selection of sugar beet genotypes under salinity stress. According to all measurements, the clustering in establishment stages and Stress Tolerance Index (STI), HSF-91018, HSF-91040, HSF-92870, HSF-92881, HSF-92884, genotypes were selected as tolerant genotypes as controls.ConclusionSensitive and tolerant genotypes were not distinguished well in hydroponic medium, which related to its potential and was mentioned in other reports. Hydroponic and perlite were in the same group for different traits especially they became less salty than soil but hydroponic system is not useful for root beet but it would be suitable for forage beet because biomass production is more in this condition. Also, soil is not suitable medium for study salinity researches because it became seven times more salty than normal condition. As a result perlite is the best medium for salinity studies in sugar beet because it becomes less salty, it has low weight and cost and has less side effects on environment. According to all measurements, the clustering in germination and establishment stages and Stress Tolerance Index (STI), HSF-91018, HSF-91040, HSF-92870, HSF-92881, HSF-92884, genotypes were selected as tolerant genotypes as controls.AcknowledgmentsThe Authors’ thanks Sugar Beet Seed Research Institute, Agricultural Research, Education and Extension organization, Karaj, Iran for supporting this research.
Breeding plants for stress conditions
Nasim Fathizadeh; Saadollah Houshmand; Shahram Mohamadi; Payam Pezeshkpour
Abstract
IntroductionLentil is a rich source of protein, fiber, minerals, antioxidants, folate, zinc, selenium, iron, and low amounts of fat and carbohydrates. Increasing water shortage and drought stress will be a major threat to global lentil production. The present study was conducted to determine the morphophysiological ...
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IntroductionLentil is a rich source of protein, fiber, minerals, antioxidants, folate, zinc, selenium, iron, and low amounts of fat and carbohydrates. Increasing water shortage and drought stress will be a major threat to global lentil production. The present study was conducted to determine the morphophysiological traits and grain of yield under normal and drought stress conditions, investigate tolerance indices and identify drought tolerance in some lentil genotypes. Materials and methodsIn this experiment, twenty - four lentil genotypes were evaluated in the research farm of Shahrekord Faculty of Agriculture in two drought-stress environments and the normal conditions of the region in two separate randomized complete block designs with three replications experiments. In the 50% flowering stage, drought stress was done by completely stopping irrigation for the genotypes. Sampling was done at the end of the growing season. In this experiment, morphophysiological and yield traits were measured. Results and discussionThe results of composite data analysis showed that the effect of environment, genotype and the interaction effect of genotype × environment were significant on most traits. The share of these sources of variation in diversity of triats was different and environment placed on the most role in the diversity of seed yield (55.27%), genotype in the diversity of 100 seed weight (64.6%) and the number of single seed pods (53.9%). Seed yield in normal agricultural conditions has a positive correlation with most of the traits. In addition, under stress conditions, more traits had a significant correlation with grain yield. STI and GMP indices were highly correlated with yield in both environments and these indices can be used to select the superior genotype. Examining the main components of the indicators showed that the first component and two components justify 97.66% of the changes, the first component was introduced as a semi-tolerant component and the second component as a tolerant component. The results of the cluster analysis put the genotypes in three general groups. The results of cluster analysis based on STI and GMP indices put the genotypes in three separate groups. ConclusionOne of the main goals of production programs in arid and semi-arid regions is the screening of germplasm in different stages of plant growth. The results of the present research showed that drought stress in the reproductive stage reduces the morphophysiological traits and yield of lentil genotypes. Based on the results of seed yield, Kimia genotype with the lowest yield loss is known as the tolerant variety and C113 variety with the highest yield loss is known as the sensitive variety. Based on the results of seed yield, Kimia genotype with the lowest yield loss is known as the tolerant variety and C113 variety with the highest yield loss is known as the sensitive variety.
Drought stress
Sajjad Nasiri; Babak Andalibi; Afshin Tavakoli; Mohammad Amir Delavar; Lukas Van Zwieten
Abstract
IntroductionBarley (Hordeum vulgare L.) is among the most influential cereals, and a wide range of populations in several regions of the world (Sallam et al., 2019). However, there are some restrictions for accomplishment to the potential production, which the most consequential one among them, water ...
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IntroductionBarley (Hordeum vulgare L.) is among the most influential cereals, and a wide range of populations in several regions of the world (Sallam et al., 2019). However, there are some restrictions for accomplishment to the potential production, which the most consequential one among them, water shortage, a drastic obstacle in many regions of the world, in particular in arid and semi-arid areas. Water scarcity, results in plenty of disturbances in plant functions like cell division and elongation, water and nutrients relations, photosynthesis, enzymes activity, stomata movement, assimilate partitioning, respiration, oxidative damage, growth, and productivity, as several types of researches show that water shortage in the soil cause many disorders in plant tissues, which in turn leads to a punctual diminish in the photosynthesis rate (Todorova et al., 2022). Under circumstances of water shortage, the electron transport through PSII is prohibited, and the oxygen-evolving complex of PSII is damaged (Georgieva et al., 2005). In repercussion, depends on the times, duration of facing, and stress intensity, developmental stage, and kind of tissue, plant defenses against it differently.Materials and methodsAn experiment as a factorial in a completely randomized block design in five replications at the experimental greenhouse of the University of Zanjan was carried out in two years 2021 and 2022. In this study two regimes of irrigation (D0, regular irrigation as the control, D1, Water Deficit for two weeks immediately after flowering), four levels of biochar (zero% as the control treatment, 0.25, 0.5 and 1 percent of soil weight) and three levels of spraying Methyl Jasmonate (zero μmol as the control treatment, 50 and 100 μmol) at the same time with flowering stage and starting withholding water, were executed.Results and discussionResults demonstrated that utilized treatments had significant effects on studied parameters. Results illustrated that, despite the fact that proline content, carbohydrate and quantity of electrolyte leakage were elevated as a result of drought stress, and accumulation of photosynthetic pigments were dwindled, however, application of biochar in the soil and foliar spraying of methyl Jasmonate caused modulating the effects of drought stress. Lack of water can reduce the concentration of photosynthetic pigments, mainly chlorophylls and carotenoids, as it causes oxidation which leads to diminishing the biosynthesis of pigments (Pandey et al., 2012). It is claimed that using biochar ameliorates the reduction of pigments in stressed plants as a result of better surface area, higher water holding capacity, more cation exchange capacity, and useful absorptive features of biochar (Ibrahim et al., 2020). Moreover, the drought stress resulted in a substantial elevation in the concentration of proline (PC) which might be as a result of devastating impacts of drought on the performance of plasma membrane as well as the process which leads to dehydration of cytoplasm, which in turn results in boosting proline concentration in Barley plants under drought situation (Hafez et al., 2020). It is said that biochar reduces proline content, because of its impact on maintenance of plasma membrane in a stable situation, modulating the pressure of water in cell, and enhancing the ability of plants in conserving relative water content (Ahmed et al., 2016). Furthermore, methyl Jasmonate (MJ) may facilitate the strengthening of cell walls and effectively neutralize excessive increase in the level of ROS during further exposure to the stress factor, thereby preventing the damage of cellular membrane structures and changes in their permeability under stress conditions (Hayat and Ahmad., 2007).ConclusionThe current study represents that Barley can tolerate drought stress through several mechanisms such as modulating some biochemical compounds. In this study drought was shown to have negative impacts on some of the studied physiological and biochemical parameters. Results demonstrated that the use of biochar and Methyl Jasmonate can improve the adaptation ability of Barley plants to water shortage, associated with enhancement in morpho-physiological and biochemical traits. Soil content of biochar at 0.25% w/w and Methyl Jasmonate leaf applies at 50 micro moles protected plants against drought stress. Importantly higher doses of biochar and Methyl Jasmonate had negative impacts, highlighting the need to better understand optimal doses, and mechanisms of action of these amendments.
Drought stress
Samaneh Ghorbi; Ali Ebadi; Saeid Khomari; Masoud Hashemi
Abstract
IntroductionDrought is known as the most important factor limiting corn production in the world. Depending on the growth stage and severity of drought stress, it can decrease corn yield by 76%. In addition, the increase in drought stress can decrease the efficiency of elements such as nitrogen in this ...
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IntroductionDrought is known as the most important factor limiting corn production in the world. Depending on the growth stage and severity of drought stress, it can decrease corn yield by 76%. In addition, the increase in drought stress can decrease the efficiency of elements such as nitrogen in this crop. Therefore, many ways have been studied to decrease the effects of drought stress on crops. The results show that the use of cover crops can be an important approach for agriculture to protect crops against climate changes. These crops improve crop yields and soil nutrients by reducing runoff and soil erosion. The use of legumes as cover crops can decrease the need for chemical nitrogen fertilizer by biological N fixation in these crops.Materials and methodsIn 2019, a pot experiment was conducted in the greenhouse of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran. The experimental treatments were faba bean cultivation (cultivated, non-cultivated), the different rates of nitrogen based on urea (0, 50, 100% of the recommended amount) and water deficit stress (40, 60, 80, 100% FC). In this experiment, 72 pots of 10 kg were used. First, the field capacity of the soil was determined, then the pots were filled with the air-dried soil. Ten grains of faba bean were planted in each pot, 5 of which were removed after germination. Shoots of faba bean were cut at the 50% flowering stage and mixed with the soil to the depth of 10 cm. Four corn grains were planted in each pot, two of which were removed after germination. In this experiment, the variety Shadan of faba bean and the corn hybrid 201 (single cross) were used. Different levels of nitrogen were applied at the V5 stage of corn, drought stress was applied ten days later and continued until the harvest stage of corn. Pots were weighed regularly for the application of drought stress. Corn was harvested at the pasty stage. Experimental characteristics included grain and shoot fresh and dry weights, grain and shoot protein content, nitrogen agronomic efficiency, nitrogen productivity, nitrogen recovery efficiency, and shoot and grain partial factor productivity. Statistical analysis of data was performed using SPSS software (version 26), and significant differences between treatment means were tested using Duncan's Multiple Range Test at P < 0.05.Results and discussionOur results showed that all traits were influenced by interactions between faba bean cultivation × N fertilizer × water deficit stress. The highest grain yield was obtained of treatment the faba bean cultivation+100% of the recommended nitrogen rate+no application of water deficit stress, while no grains were observed in the treatment of non-cultivation of faba bean+100% of the recommended rate of nitrogen+application of severe water deficit stress, non-cultivation of faba bean+no nitrogen application+application of moderate water deficit stress and non-cultivation of faba bean+no nitrogen application+application of severe water deficit stress. The higher rate of nitrogen in the soil under severe water deficit stress can be considered as the limiting factor for crop growth, and therefore we observed lower yields in these treatments. Addition, our results showed that faba bean cultivation as cover crop increased some traits such as fresh and dry weight of shoot, agronomic efficiency and nitrogen recovery of nitrogen compared to non-cultivation of faba bean. The highest fresh dry shoot weight was obtained from the treatments of faba bean cultivation+100% of the recommended nitrogen rate+no application of water deficit stress and non-cultivation of faba bean cultivation+100% of the recommended nitrogen rate+no application of water deficit stress. Also, the highest shoot and grain agronomic efficiency was observed from the faba bean cultivation+100% of the recommended nitrogen rate+ no nitrogen application+application of moderate water deficit stress.ConclusionOverall, our results showed that the use of faba bean as cover crop can decrease the effects of water deficit stress and improve the growth status of corn, although the increase at higher water deficit stress level is lower than the other levels. Based on the results, it can be concluded that the use of faba bean as cover crop and and 50% of the recommended rate of nitrogen can be recommended under the same conditions (under water deficit stress).
Breeding plants for stress conditions
Zohreh Hajibarat; Abbas Saidi; Ahmad Mousapour Gorji
Abstract
IntroductionThe interaction of genotype with the environment provides the possibility of selecting stable genotypes for a wide range of environments. Evaluation of the interaction of genotype with the environment is necessary to increase the efficiency of selecting varieties with high and stable performance ...
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IntroductionThe interaction of genotype with the environment provides the possibility of selecting stable genotypes for a wide range of environments. Evaluation of the interaction of genotype with the environment is necessary to increase the efficiency of selecting varieties with high and stable performance in a wide range of different environments. The objectives of this paper are: (1) evaluating the stability of 60 potato genotypes for tuber yield in two years using parametric and non-parametric stability methods, (2) identifying genotypes with good and stable performance when evaluated in variable environments and (3) investigating the relationship and correlation between stability statistics of tuber performance under water deficit conditions in Iran.Materials and methodsTo evaluate the performance stability and adaptability of the 60 potato genotypes, two cultivars and 58 advanced clones, 17 parametric and non-parametric statistics were evaluated for tuber yield across eight environments during the 2018-2019 growing seasons. The genotypes were evaluated under normal and water deficit conditions in Karaj and Ardabil. In this study, the parametric analysis for yield was determined by such parameters as regression coefficient (bi), environmental variance (Si2), coefficient of variation (CVi), deviation from regression (sdi2), and Wricke’s ecovalence (Wi2), The non-parametric analysis included Nassar and Huhn's statistics (S(1) and S(2)), Huhn's equation (S(3) and S(6)), Shukla’s stability variance (σ2i), Plaisted and Peterson’s (θi), Thennarasu’s non-parametric (NP(1), NP(2), NP(3), and NP(4)), and Kang’s rank-sum (KR) parameter. Parametric and non-parametric statistics are used by agronomists and plant breeders. Currently, researchers are interested in applying several stability statistics to obtain the desired results, crucial for the selection of stable varietiesResults and discussionComposite variance analysis showed that the effect of place and year as well as the effect of genotype are significant. The interaction effect of year × location × genotype was significant at the probability level of 1%. The genotype effect was also significant at the 1% probability level. The interaction effect of genotype x location and genotype x year was not significant, which indicates that the average performance of genotypes is not different in different locations and years. Grouping of genotypes based on average performance and parametric and non-parametric stability statistics showed that genotypes are divided into four main groups. In general, based on the average rank of parametric and non-parametric stability parameters, genotypes G31, G21 and G36 had the least changes and were recognized as the most stable genotypes, and therefore they can be introduced as stable genotypes. The results of stability statistics and cluster analysis showed that G31, G21 and G36 genotypes can be introduced as stable and compatible genotypes.ConclusionOur results showed that G21, G31 and G36 genotypes contributed the least to the genetic × environment interaction (G*E) and were considered as stable genotypes under water deficit conditions. The different parametric and non-parametric stability procedures can be proposed to select drought tolerant genotypes under different environments conditions; these procedures could be useable for recognition of the best genotypes under drought stress conditions. Therefore, the analysis of yield stability could be utilized in combination with parametric and non-parametric methods to evaluate and identify drought tolerance genotypes. Dendrogram results confirmed each other with the results of parametric and non-parametric statistics. While G49, G51, G53 and G56 genotypes with the highest values were the most unstable genotypes.
Drought stress
Mansour Esmaily; Mohammad Reza Dadashi; Mohamad Taghi Fayzbakhsh; Kami Kaboosi; Fatemeh Shaikh
Abstract
IntroductionMaize cultivation is rapidly expanding in the world due to its high adaptability to different weather conditions, and it is an exceptional product that can be effectively used as feed and forage products to meet the ever-increasing needs of livestock. Low irrigation is an approach to increase ...
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IntroductionMaize cultivation is rapidly expanding in the world due to its high adaptability to different weather conditions, and it is an exceptional product that can be effectively used as feed and forage products to meet the ever-increasing needs of livestock. Low irrigation is an approach to increase water productivity with the view of increasing production per unit of water consumption. The research results show that water stress has a significant effect on the quantity and quality of forage. Lack of water is one of the important factors in reducing the level of corn, so this experiment was conducted in order to check the possibility of saving water consumption by using low irrigation method and choosing the best hybrid in low irrigation conditions.Materials and methodsIn order to investigate the effects of low irrigation and different maize hybrids on the quantitative and qualitative traits of maize forage in the Gorgan region, an experiment was conducted in split plots arranged in a randomized complete block design with three replications in the Iraqi station of the Gorgan. Low irrigation was implemented in four levels in the main plots (100, 75, 50% and 25% of water requirement) and subplots in four levels (including hybrids SC703, SC704, ZP548 and BK50). To determine the amount of water consumption three days after each irrigation, the amount of moisture was determined by sampling the soil and immediately after reaching 40 to 60% usable moisture, irrigation was done. Irrigation was done as a drip using tapes, the distance between the nozzles was 20 cm and the amount of water output per nozzle was 2 liters per hour. Harvesting was done from the two middle lines by removing half a meter at the beginning of the row and weighed separately (leaf, stem, cob) in a separate laboratory, and their fresh weight was recorded and then placed in an oven with a temperature of 65 degrees Celsius for 72 hours, Then the dry weight was calculated. The samples of dry forage were sent to the laboratory of Forests and Ranges Organization (Tehran) and the amount of protein, fiber and other quality attributes of forage were measured by infrared spectrometry with PertenInformatic 8620. The data were analyzed using SAS 9.1.3 statistical software and the means were compared with the LSD test at the 5% probability level.Results and discussionThe results of analysis of variance showed that low irrigation effect was significant on all studied traits. Also, the effect of the studied hybrids on all the traits was significant except for insoluble fibers in acidic detergent and water-soluble carbohydrates. Also, the interaction effect of hybrid × low irrigation was significant only on forage yield (Total biomass, ear fresh weight, stem and leaf fresh weight, and total dry weight). The results of means comparison showed that the highest biomass yield was observed in the 100% water demand treatment, which was 7.2, 49, and 79.7% higher than the 75, 50, and 25% irrigation treatments, respectively. However, the highest water consumption efficiency with a significant difference compared to other levels was observed in the treatment of 75% water requirement (5.99 kg m-3). Also, with the increase of irrigation levels, the amount of crude protein, crude fiber, water-soluble carbohydrates and insoluble fibers in the neutral environment increased significantly, and among the studied hybrids, the SC703 hybrid had the highest forage yield (43692.4 kg ha-1).ConclusionConsidering the shortage and high economic value of water, the reduction in rainfall and the occurrence of successive droughts in recent years, optimum use of water can allocate more land to irrigated cultivation in addition to achieving appropriate and economic performance. The results showed that the lack of water reduces all quantitative traits. Among the studied hybrids, SC703 had the highest forage yield per unit area. On the other hand, low irrigation treatment at the level of 75% of the total water requirement is recommended to achieve the highest water consumption efficiency in Gorgan region.
