Breeding plants for stress conditions
Amir Gholizadeh; Mostafa Khodadadi
Abstract
IntroductionCoriander is an annual herb of the umbel family and is belonged from North Africa to south-western of Asia. Coriander is one of the important medicinal plant that used in the pharmaceutical industry and it mainly cultivated and widely distributed for the fruits. The dried fruits are widely ...
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IntroductionCoriander is an annual herb of the umbel family and is belonged from North Africa to south-western of Asia. Coriander is one of the important medicinal plant that used in the pharmaceutical industry and it mainly cultivated and widely distributed for the fruits. The dried fruits are widely employed as a condiment, especially for flavoring of sauces, meat products and bakery and confectionery items. Also, coriander fruits are as a source of essential oils and fatty oil. Water deficit stress is one of the most important factors limiting the growth and survival of plants in arid and semi-arid regions of the world. Water is a major component of the fresh produce and significantly effects on weight and quality of plants. Also, water deficit may cause significant changes in the yield and composition of essential oils in aromatic and medicine plants. So that, was reported that water deficit increased essential oil percentage in coriander but decreased essential oil yield. Iran with an average annual rainfall of 240 mm is included among arid and semi-arid regions of the world. Of the million hectares of cultivated region, only five millions are under irrigation because of intense water limitations. However, Iran is one of the world’s commercial coriander producers. Coriander has been cultivated for many years in different parts of Iran. Therefore, development of drought-tolerant cultivars with high essential oil yield is important in coriander. This research was conducted in order to evaluate the effect of drought stress on morphological, physiological and phytochemical characteristics of endemic coriander genotypes.Materials and MethodsF2 generations derived from half-diallel crosses of six endemic coriander genotypes including Isfahan, Hamedan, Bushehr, Mazandaran, Markazi and Alborz, together with their parents were evaluated in randomized complete block design with three replications in each experiment during growing season of 2016 in the research field of Tarbiat Modares University. Plants were treated with different levels of water treatment: well watered (WW), moderate water stress (MWS) and severe water stress (SWS). Data were collected on fruit yield, oil content and oil yield. GGE biplot statistical method (genotype effect + genotype × environment interaction) was used to study stability of genotypes in the studied environments.Results and DiscussionResults of Combined analysis of variance indicated that the effects of environments, genotypes and genotype × environment interaction were significant, suggesting that the genotypes responded differently in the studied environment conditions. So, there was the possibility of stability analysis. Results of stability analysis using GGE biplot method indicated that the two first and second principal components of the GGE biplot explained 71.9% of the total essential oil yield variation. Based on the hypothetical ideal genotype biplot, the genotypes G17 (Mazandaran Hamadan) and G4 (Alborz Mazandaran) were better than the other genotypes across environments for essential oil yield and stability and had the high general adaptation to all environments. Furthermore, the genotype G18 (Mazandaran Bushehr) in E2 and E3 environments and genotype G9 (Markazi Mazandaran) in E1 environment were superior genotypes with the high specific adaptation. Comparison of the studied environments showed that the E2 and E3 environments were quite similar in ranking, grouping and assessing stability of the genotypes, whereas the E1 environment was different from the other environments. Overall, the results showed that all environments had high discriminating ability so that could able to show differences between genotypes. The moderate stress environment was the nearest environment to ideal environment that had the highest discriminating ability and representativeness.ConclusionGenerally, the results indicated that all environments had high discriminating ability so that could able to show differences between genotypes. Also, the genotypes G17 and G4 as stable and drought tolerant genotype can be considered as donor parent which contains drought tolerance genes and could be used to improve coriander high essential oil yield in drought condition.AcknowledgementsThe authors thank from the Gene bank of the Seed and Plant Improvement Institute of Karaj, Iran for making available plant materials.
Salinity stress
Jafar Nabati; Morteza Goldani; Mohammad Mohammadi; Syadeh Mahbobe Mirmiran; Ali Asadi
Abstract
IntroductionSalinity stress is one of the most important abiotic stresses which results in significant damages to agricultural production, which has affected about 20% of the world's agricultural lands, and its constantly increases. Plant responses to salinity stress have been depending on the severity, ...
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IntroductionSalinity stress is one of the most important abiotic stresses which results in significant damages to agricultural production, which has affected about 20% of the world's agricultural lands, and its constantly increases. Plant responses to salinity stress have been depending on the severity, species, and even genotype. Different accessions of a species may also use different mechanisms to cope with salinity stress and complete their life cycle. Therefore, the identification mechanism of salt-tolerant plants is necessary to select plants for high salinity conditions. With the development of the cultivation of tolerance plants in saline soils, it is possible to use the soil more efficiently; but salt tolerance is controlled by complex physiological and genetic processes, and understanding these mechanisms is essential to improving yield in saline soils. Different strategies can be used to prevent a decrease in yield in these areas. Plant adaptation to salinity stress in low or medium salinity stress has been suggested as a way to increase plant yield in saline soils. Considering the importance of salinity stress and also the beneficial environmental effects of legumes on crop rotation as well as the role of physiological and antioxidant characteristics in salinity tolerance and genetic diversity between lentil genotypes, this study was conducted to select lentil genotypes under salinity in a controlled environment.Materials and methodsThis study was carried out in hydroponic conditions in the greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad Iran in 2019. The experiment was performed as split plots in a randomized complete block design with three replications. The 24 lentil genotypes were selected in the pretest and two salinity stress levels 12 and 16 dS.m-1 and 0.5 (control) were investigated. Seeds of lentil genotypes were prepared from the seed bank of the Research Center for Plant Sciences, Ferdowsi University of Mashhad. Seeds were sown in the hydroponic environment in the greenhouse with light and dark periods according to natural day length, day and night temperatures of 25 and 18 °C respectively with ±5 °C variations and natural light conditions. One week after planting, salinity stress was applied. Four weeks after applying salinity stress, traits including photosynthetic pigments, DPPH radical activity, malondialdehyde, total phenol, soluble carbohydrates, catalase, peroxidase, ascorbate peroxidase, osmotic potential, and proline were measured. To calculate the percentage of survival before salinity stress, the number of plants was recorded and before harvest, the number of live plants was recorded and the percentage of survival was calculated.Results and discussionThe results showed that at the salinity of 12dSm-1 MLC6, MLC12, MLC26, MLC120 and MLC178 had a survival of over 60%. Under 16dSm-1 salinity except for MLC57, MLC73, MLC94, MLC104, and MLC108 genotypes, other genotypes survived and MLC178 and MLC26 genotypes had the highest survival with 30% and 25%, respectively. With increasing salinity stress levels, the content of chlorophyll a, total photosynthetic pigments, and total phenol in all genotypes had a decreasing trend. Chlorophyll a content increase with an increase salinity from controll (0.724 mg.g-1 Fw) to 16 dSm-1 (0.220724 mg.g-1 Fw). Osmotic potential with increasing salinity was a more negative state of values at 16dSm-1 of MLC178 (-3.91 MPa) and MLC26 (-5.62 MPa). Increasing salinity stress from 0.5 to 16 dS.m-1 increased inhibition of the free radical activity of DPPH, activity of catalase, peroxidase, and ascorbate peroxidase in MLC117 and MLC178 genotypes. Also, except for two genotypes, MLC5 and MLC14, the other remaining genotypes had a good ability to reduce the osmotic potential at the salinity of 16dSm-1. Principal component analysis (PCA) showed that the first component explained 50.14% of the changes and properties related to photosynthetic pigments and osmotic potential and the second component explained the antioxidant properties, metabolites, and survival percentage with 12.66%.ConclusionGenerally, results showed the superiority in most of the studied traits of the MLC6, MLC12, MLC26, MLC117, MLC120, and MLC178 compared to the total average. Due to the relative superiority of this genotypes of genotypes, it is recommended that perform additional studies to evaluate their salinity tolerance in field conditions.
Drought stress
Meysam Miri; Mohammad Reza Amerian; Mohsen Edalat; Mehdi Baradaran Firouzabadi; Hasan Makarian
Abstract
IntroductionDrought stress is one of the affecting factors on physiological traits in arid and semi-arid regions, especially in Iran. Recently, the role of polyamines has been considered to increasing plant tolerance to stresses, including drought. Polyamines are a new group of growth regulators and ...
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IntroductionDrought stress is one of the affecting factors on physiological traits in arid and semi-arid regions, especially in Iran. Recently, the role of polyamines has been considered to increasing plant tolerance to stresses, including drought. Polyamines are a new group of growth regulators and are involved in a wide range of physiological and biochemical processes such as stress resistance, phospholipid membrane stability and osmotic regulation (zakai, khosroshahi and duodenal, 2008). The aim of this experiment was to investigate the effect of seed pretreatment and seedling foliar application with melatonin and spermidine on kodo physicochemical traits under drought stress in laboratory and greenhouse.Materials and methodsIn this study, experiments were performed in two stages. In the first stage (laboratory), the experiment was performed as a two-factor split factorial in the form of completely randomized blocks with four replications. Experimental treatments including drought stress as the main factor in seven levels of zero osmotic potential (control), -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa, pretreatment seeding with spermidine at five levels, zero, 0.5, 1, 1.5 and 2 mM and pre-seeding with melatonin at five levels, zero, 0.125, 0.250, 0.375 and 0.500 mM were sub-factors. After performing the first stage, the best experimental treatments were selected and in the next stage (greenhouse), the experiment was performed as a three-factor split factorial in the form of completely randomized blocks with three replications. Drought stress was the main factor in three levels of irrigation in 10% of field capacity depletion (optimal irrigation), irrigation in 40% of field capacity depletion (mild stress) and irrigation in 70% of field capacity depletion, seed pre-selection as a secondary factor at three levels: no pre-treatment (control), pre-treatment with spermidine, pre-treatment with melatonin and also seedling foliar application was applied as a sub-factor at three levels: no foliar application, spermidine foliar application and solution Spraying with melatonin.Results and discussionThe results showed that concentrations of 1.5 spermidine and 0.375 mM melatonin had the highest percentage and germination rate. In the greenhouse, experimental treatments showed a significant effect on increasing stomatal conductance, relative leaf moisture, and catalase enzyme and leaf soluble protein. In general, seed pretreatment as well as seedling foliar application with 0.375 mM melatonin had the greatest effect on drought stress modulation.ConclusionThe results showed that concentrations of 1.5 spermidine and 0.375 mM melatonin had the highest percentage and germination rate. In the greenhouse, experimental treatments showed a significant effect on increasing stomatal conductance, relative leaf moisture, and catalase enzyme and leaf soluble protein. In general, seed pretreatment as well as seedling foliar application with 0.375 mM melatonin had the greatest effect on drought stress modulation.
Drought stress
Morteza Ghorbany; Hamid-Reza Fallahi; Mahsa Aghhavani-Shajari; Sohrab Mahmoodi; Hamidreza Ramazani
Abstract
IntroductionAbiotic environmental stresses such as drought and salinity are important factors in reducing crop yield in many parts of the world (Muscolo et al., 2016). Water scarcity is the most important factor in reducing the production of crops in arid areas. Therefore, it is necessary to pay attention ...
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IntroductionAbiotic environmental stresses such as drought and salinity are important factors in reducing crop yield in many parts of the world (Muscolo et al., 2016). Water scarcity is the most important factor in reducing the production of crops in arid areas. Therefore, it is necessary to pay attention to the sustainable use of water resources, especially in arid and semi-arid regions (Dabhi et al., 2013; Samadzadeh et al., 2020). Introducing new drought-tolerant crops is the main strategy for sustainable crop production in arid regions (Samadzadeh et al., 2020). Besides, deficit irrigation and foliar application of osmolyte compounds such as glycine betaine can be considered to reduce the effect of drought stress on plant growth and yield (Fallahi et al., 2015; Tian et al., 2017).Materials and methodsIn this experiment, the effects of water availability and foliar application of glycine betaine (GB) were studied on the growth and yield of quinoa. The experiment was carried out as factorial based on a complete randomized block design with three replicates in Sarayan, south Khorasan province, Iran. Experimental factors were (1) irrigation management regimes (irrigation after 70, 140, and 210 mm pan evaporation) and (2) GB foliar application (0 zero or distilled water and 150 mg. l-1).Results and discussionThere were no significant differences between irrigation levels in terms of many vegetative and reproductive parameters such as plant height, plant dry weight, number of panicles per plant, panicle length, and its dry weight. An increase in water stress severity caused a reduction in biological yield and 1000-grain weight, but seed yield did not decrease. GB application increased the values of plant dry weight, biological yield, chlorophyll index (SPAD), and the number of panicles per plant, while reduced reducing seed yield. Interaction results of experimental factors revealed that the highest biological yield (2533.3 kg ha-1) was obtained by GB and irrigation after 70 mm pan evaporation, while the lowest value (1433.3 kg ha-1) was gained by the no-GB and 210 mm pan evaporation. The highest seed yield values were obtained by 70 and 210 mm pan evaporation (250.7 and 245.4 kg ha-1, respectively) combined with the no-GB application. In general, due to the scarcity of water resources in arid areas, quinoa irrigation after 210 mm pan evaporation can be recommended.ConclusionQuinoa had an acceptable resistance to drought stress. Seed yield in this experiment was much lower than the plant's genetic potential, which could be due to improper planting date and density. Therefore, research on other quinoa cultivars, other planting dates, and foliar application of glycine-betaine at other concentrations and times can complement the results of the present experiment.
Drought stress
Mitra Rostami Hir; Parisa Sheikhzadeh; Saeed Khomari; Nasser Zare
Abstract
IntroductionOilseed rape (Brassica napus L.) is one of the most critical oilseed plants ranked third in oil production after soybeans and palm. Drought stress, especially at the end of the growing season, is the most critical environmental stress affecting the growth, development, and production of crop ...
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IntroductionOilseed rape (Brassica napus L.) is one of the most critical oilseed plants ranked third in oil production after soybeans and palm. Drought stress, especially at the end of the growing season, is the most critical environmental stress affecting the growth, development, and production of crop plants. The development of practical strategies for increasing drought tolerance is crucial to sustaining crop production, particularly in arid and semi-arid regions. The utilization of micronutrients such as molybdenum is one of the best strategies to increase drought stress tolerance in plants. This micronutrient is one of the most valuable and practical approaches for improving plant growth and plant adaptation under drought-stress conditions. The present study aimed to investigate the effect of foliar application of molybdenum oxide nanoparticles on the photosynthetic indices and biochemical traits in oilseed rape under end-season drought stress conditions.Materials and methodsTo investigate the effect of molybdenum oxide nanoparticles on the photosynthetic indices, some biochemical traits, and grain yield of winter oilseed rape under the end-season drought stress, a split-plot experiment based on randomized complete block design (RCBD) was conducted with three replications at a research farm station of the University of Mohaghegh Ardabili in 2018-2019. The experimental treatments included irrigation (regular irrigation until the end of the season (control) and omitting irrigation from the flowering stage) as the main plots and molybdenum oxide nanoparticles foliar application (0 (control), 25, and 50 mg.L-1) as sub-plots. Drought stress was applied through irrigation stopping at the flowering stage (50% flowering). One week after the second spraying, the chlorophyll fluorescence including minimum fluorescence (F0), maximum fluorescence (Fm), variable fluorescence (Fv), and maximum quantum efficiency of photosystem II (Fv/Fm) was measured. Furthermore, chlorophyll pigments (chlorophyll a, chlorophyll b, and total chlorophyll), carotenoid, and proline content, and the activity of antioxidant enzymes (peroxidase and catalase) were measured in the leaf samples of treated and control plants. Analysis of variance and comparison of means was carried out using SAS 9.1 software. The means were compared using Duncan’s Multiple Range (DMRT) tests at the 5% probability level.Results and discussionThe results showed that irrigation and foliar application of molybdenum oxide nanoparticles treatment significantly influenced the photosynthetic and biochemical properties of winter oilseed rape. Furthermore, F0, Fv/Fm, proline content, and grain yield were significantly influenced by irrigation × molybdenum oxide nanoparticles interaction. The end-season drought stress significantly decreased the chlorophyll a, b, and total chlorophyll, carotenoid, Fm, Fv, Fv/Fm, and grain yield and increased F0, the activity of peroxidase and catalase enzymes, and the proline content in winter oilseed rape leave. Chlorophyll pigments, Fm, Fv, Fv/Fm, proline content, and peroxidase and catalase enzyme activity in oilseed rape leaves were increased with the application of different concentrations of molybdenum oxide nanoparticles. Foliar spraying with 25 mg.L-1 molybdenum oxide nanoparticles caused a significant increase in the content of the photosynthetic pigment, including chlorophyll a, b, total chlorophyll, and carotenoid content (about 25.81, 24.88, 25.57, and 17.78 present, respectively) as compared to the control treatment. Under regular irrigation and drought stress conditions, molybdenum oxide nanoparticles improved the maximum quantum efficiency of photosystem II and grain yield by decreasing the F0 (about 11.37%) and increasing the Fv (about 7.22%). The highest activity of the catalase and peroxidase enzymes was obtained with the application of 25 mg.L-1 molybdenum oxide nanoparticles, which was significantly higher than that of the control. Under drought stress conditions, proline content in the foliar sprayed plants with 25 and 50 mg.L-1 of molybdenum oxide nanoparticles was significantly higher than that of the control plants.ConclusionThe results of the present study showed that end-season drought stress significantly reduced the photosynthetic pigments and chlorophyll fluorescence including Fm, Fv, and Fm/Fv, and increased F0 in oilseed rape plants. Molybdenum oxide nanoparticle reduces oxidative damage of drought stress, by improving the enzymatic (activity of catalase and peroxidase enzymes) and non-enzymatic (metabolites) antioxidant systems. Furthermore, molybdenum oxide nanoparticles increased the content of the photosynthetic pigment and decreased the minimum fluorescence (F0) of chlorophyll under drought stress, which ultimately significantly increase the maximum quantum efficiency of photosystem II. Generally, although the foliar application of different concentrations of molybdenum oxide nanoparticles reduced the damage caused by the end-season drought stress oilseed rape, the highest increase in the photosynthetic and biochemical traits was obtained with 25 mg.L-1 molybdenum oxide nanoparticles. Therefore, the application of 25 mg.L-1 molybdenum oxide nanoparticles on oilseed rape plants can be used for reducing the destructive effects of drought stress and increasing crop tolerance to end-season drought stress.
Drought stress
Sadegh Nasirpour; Mohammadreza Jahansouz; Ali Ahmadi; Esmaeil Afshoon
Abstract
IntroductionMaize (Zea mays L.) is ranked fourth among cereals in terms of area under cultivation and grain yield after wheat, barley and rice. Water scarcity or water stress is one of the most limiting factors in crop growth and crop yield, which reduces the average yield by 50% and even higher values. ...
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IntroductionMaize (Zea mays L.) is ranked fourth among cereals in terms of area under cultivation and grain yield after wheat, barley and rice. Water scarcity or water stress is one of the most limiting factors in crop growth and crop yield, which reduces the average yield by 50% and even higher values. Water stress in corn through adverse effects on inoculation and grain filling, reduced plant photosynthesis, reduced amount of material grown and as a result of grain shrinkage, reduced leaf area and disrupting physiological processes, reduces the number of grains per ear, weight Thousands of seeds, bio-yield and grain yield. Conservation tillage is one of the inevitable methods of conservation agriculture by which the effect of water stress on plant growth and yield can be reduced. In agro-ecosystems, conservation tillage, while preserving and improving water resources and the environment, improves crop production and makes it sustainable. Since Iran is located in the arid and semi-arid region of the world and drought has a negative impact on the yield of its products, the study of water stress and strategies to deal with it is of particular importance; Therefore, the purpose of this study was to investigate the yield response and yield components of maize to tillage systems and irrigation regimes in Karaj. Materials and methodsIn order to evaluate the effect of different tillage systems and irrigation regimes on corn yield, an experiment was conducted as split-plot in the form of randomized complete blocks with three replications in the research farm of the University of Tehran (longitude 35 degrees East, latitude 35 degrees and 48 Minute North) in 2016. The main factor in this experiment was tillage with two levels (no-tillage and conventional tillage) and the second factor was irrigation with three levels (without water stress, moderate water stress and severe water stress based on 75, 110 and 150 mm evaporation from Evaporation pan surface, respectively). Irrigation was done using plastic tapes (type) and the irrigation volume was controlled by the meter. Irrigation treatments were applied from the 4-leaf stage. The distance between the main, sub-factors and blocks (replicates) was 10, 2 and 10 meters, respectively, and there were six 10-meter planting lines within each experimental plot. Also, the distance between rows of corn in the plots was 75 cm and the distance between plants per row was 15.5 cm (density of 86,000 plants per hectare). To determine the water requirement, the Class A evaporation pan method was used and using daily meteorological data, Equations 1 and 2 were used:ETC = KC × ET0 (Eq. 1)ET0 = K p × E pan (Eq. 2)in them, ETc = Evapotranspiration of the desired crop (mm.day-1), KC= Plant coefficient, ET0= Reference evapotranspiration (mm.day-1), Kp= Plate coefficient (without unit), E pan= Evaporation of the pan (mm.day-1)ResultsThe results showed that the effect of tillage and tillage interaction at irrigation levels on any of the traits was not significant, but the effect of irrigation regimes on plant height, number of seeds per ear, 1000-seed weight, ear weight, grain yield, Biological yield, harvest index and water use efficiency were significant. The highest plant height was obtained in conditions without water stress (217 cm). Also, the highest number of seeds per ear was obtained under normal irrigation conditions, so that the application of severe stress reduced the number of seeds per ear by 26%. Severe water stress reduced the weight of 1000 seeds by 12%. Also, the weight of ear decreased by 38% compared to normal irrigation in severe stress and reached 151 g. The highest grain yield in normal irrigation was 12471 kg.ha-1, which severe stress reduced grain yield by almost 40%. A similar trend was observed in biological yield, with severe water stress reducing by 29%. In terms of water use efficiency, severe water stress increased it to 2.21 kg.m-3, which showed a growth of 31% compared to normal irrigation.ConclusionThe results of this study showed that the tillage system had no significant effect on any of the traits, but water stress had a negative effect on all traits except water use efficiency, so that plant height, 1000-seed weight, Number of seeds per ear, ear weight, grain yield, biological yield and harvest index decreased sharply but water use efficiency increased compared to treatment without water stress. Based on the results of this study, corn irrigation based on 75 mm of evaporation from the evaporation pan surface in similar climatic conditions is recommended.
Salinity stress
Hamed Narimani; Raouf Seyed Sharifi
Abstract
IntroductionSoil salinity is one of the most important abiotic stresses that can limit plant growth and yield. The response of plants to soil salinity has been evaluated based on genetic, biochemical and morpho-physiological traits. Several strategies have been developed in order to decrease the toxic ...
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IntroductionSoil salinity is one of the most important abiotic stresses that can limit plant growth and yield. The response of plants to soil salinity has been evaluated based on genetic, biochemical and morpho-physiological traits. Several strategies have been developed in order to decrease the toxic effects caused by soil salinity on plant growth. Among them the use of bio fertilizers (such as Mycorrhiza) and application of methanol play a key role in yield improvement. The mechanisms that AMF employ to enhance the salt tolerance of plants to grow and develop in saline environments include facilitating water and nutrient absorption through hyphae, maintaining more favorable K+/Na+ ratios to alleviate toxic ions effects. Also, foliar application of methanol is a method which increases crop CO2 fixation. In most cases, 25% of the carbon in C3 plants is used for photorespiration, and the amount of photorespiration can be minimized by the foliar application of methanol because methanol is rapidly metabolized to CO2 in plant tissue. So, the aim of this study was to investigate the effects of methanol and Mycorrhiza application on dry matter remobilization, grain filling components and yield of barley under soil salinity.Materials and methodsAn experiment was conducted as factorial based on randomized complete block design with three replications in greenhouse research of Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili during 2020. Factors experiment were included salinity in three levels (no application of salinity as control, salinity 35 and 70 mM by NaCl), application of mycorrhiza (no application of mycorrhiza as control, application of mycorrhiza mosseae, mycorrhiza intraradices and both application mycorrhiza mosseae and intraradices) and methanol foliar application in three levels (foliar application with water as control, foliar application 15 and 30% volume of methanol). Foliar application with methanol was done in two stage of period growth (Stem elongation and Flag leaf development). The barley cultivar "Khorram" was used in the experiment with plant density of 400 seeds m-2.To study the grain filling parameters in each sampling, two plants in each vase were taken. The first sampling was taken on day 16 after heading, and other samplings were taken in 4-days intervals to determine the accumulation of grain weight. At each sampling, grains were removed from spikes manually and were dried at 130°C for 2 h. We applied grain dry weight and number to estimate the mean grain weight per sample. Following Borrás and Otegui (2001), we calculated total duration of grain filling for each treatment combination through fitting a bilinear model: GW = a+ bt0 t<t0 = a +bt t>t0Where GW is the grain dry weight; a, the GW-intercept; gfr, the slope of grain weight indicating grain filling rate; daa, the days after earring; and pm, physiological maturity. Borrás et al. (2004) determined grain filling using a bilinear model. Effective grain filling period (EGFD) was calculated from the following equation: EGFD = HGW/GFRWhere EGFD, HGW and RGF are effective grain filling period, maximum of grain weight (g) and grain filling rate (g.day-1), respectively.Conversely, an increase in grain weight in filling period was calculated using the above-cited equation in statistical software SAS 9.1 via Proc NLIN DUD method. At plant maturity, grain yield in each pot were harvested five plants per pot. 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 (Duncan) test at the 0.05 probability level.Results and discussionThe results showed that both application of mycorrhiza mosseae and intraradices and foliar application of 30% volume of methanol increased the leaf protein content, current photosynthesis and contribution of current photosynthesis in grain yield. But decreased dry matter remobilization from stem, shoot and contribution of dry matter remobilization in grain yield. Also, both application of mycorrhiza mosseae with intraradices and foliar application of 30% volume of methanol under no application of salinity increased root weight and volume (65.12 and 84.14% respectively), plant height (53.15%), spike length (63.63%), 100-seed weight (84.76%), maximum of grain weight (74.32%), grain filling period and effective grain filling period (31.78 and 73.9%, respectively), grain yield (38.52%) in compared to no application of mycorrhiza and methanol under 70 mM soil salinity.ConclusionBased on the results, it seems that the application of mycorrhiza and methanol can increase the grain yield of barley under soil salinity by improving photosynthesis and grain filling components.
Drought stress
Massih Tavakkol Afshari; Ahmad Nezami; Mohammad Javad Ahmadi-Lahijani; Jafar Nabati; Hedayat-allah Karimzadeh Soureshjani
Abstract
IntroductionThe proper planting date is known as one of the most important agronomic programs to achieve the optimal yield in crops through increasing adaption of plants to environmental conditions and improving resource use efficiency. The synchronization of growth stages with climatic parameters in ...
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IntroductionThe proper planting date is known as one of the most important agronomic programs to achieve the optimal yield in crops through increasing adaption of plants to environmental conditions and improving resource use efficiency. The synchronization of growth stages with climatic parameters in terms of rainfall, temperature, and humidity is considered as the main consequence of proper planting dates. One of the most basic methods for improving water consumption patterns in the agriculture sector is the accurate management of cropping and breeding methods, so the implementation of policies to change the pattern of cultivation based on comparative advantage, efforts to reduce the level of crop cultivation requiring high water consumption and developing drought-resistant plants. In this regard, water scarcity is a well-known factor in reducing quinoa yield under arid and semi-arid areas, which can seriously affect crop profitability. Thus, the present study aimed to evaluate the different planting dates and irrigation rounds on physiological traits and growth yield and component yields of quinoa under Mashhad climate.Materials and methodsThe current study was conducted at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in 2020. The experiment was designed as a split-plot arrangement based on randomized complete block design with three replications: planting date (July 6th, July 23th, and August 6th) as main plots and water deficit regimes (7, 14, and 21-d intervals) as subplots. The experimental data were analyzed using SAS 9.4. The mean values were statistically compared according to the least significant difference (LSD) test at the level of 5%.Results and discussionAccording to the results, decreasing water availability significantly caused an increase in chlorophyll a, chlorophyll b, and carotenoid contents. Also, leaf osmotic potential at the planting date of August 6th significantly decreased up to 39%, compared with the planting date of July 6th. It seems that in the case of increasing temperature, with increasing leaf osmotic potential, the plant resistance to environmental conditions would be improved. The content of soluble carbohydrates as well as the activity of ascorbate peroxidase and peroxidase enzymes were significantly affected by the interaction between planting date and irrigation. The highest amount of ascorbate peroxidase enzyme was observed in the 21-d irrigation cycle and planting date of August 6th. Ascorbate activity increased with increasing drought stress. The highest content of soluble carbohydrates was found on the date of planting on July 23th and the 14-d irrigation cycle. In addition, grain yield at the 21-d irrigation cycle decreased by 25% compared to the 7-d irrigation cycle. Moreover, the highest grain yield was obtained from the planting date of august 6th (544 g.m-2). Water shortage during the root development stage is a limiting factor against the optimal yield of quinoaConclusionBased on the results, a planting date on August 6th with a 14-d irrigation cycle can be recommended to achieve the desired yield of quinoa along with reducing water consumption in the Mashhad region.
Drought stress
Hassan Nouriyani; Seyed Hojjatollah Jafarinia
Abstract
IntroductionWater stress is one of the most important threatening factors for the production of crop plants in the arid and semi-arid regions of the world. Understanding plant responses to drought is of great importance and also a fundamental part of making crops stress tolerant. Water stress reduces ...
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IntroductionWater stress is one of the most important threatening factors for the production of crop plants in the arid and semi-arid regions of the world. Understanding plant responses to drought is of great importance and also a fundamental part of making crops stress tolerant. Water stress reduces plant growth and manifests several morphological, physiological and biochemical alterations leading to massive loss in yield of major crops including Rye. Drought susceptibility of a genotype is often measured as a function of the reduction in yield under drought stress, while the values are confounded with differential yield potential of genotypes. The aim of this study was to evaluate the effect of water deficit stress on some physiological, biochemical traits and yield of three Rye cultivars.Materials and methodsThis experiment was carried out as split plot based on randomized complete block design with three replications in Dezful region during 2014-2015 growing season. Treatments included water deficit stress (irrigation after 75, 1000 and 150 mm evaporation from Class A evaporation pan) in main plots and three rye cultivars (Stratoskaya, Danko, Montanum) were in subplots. The evaluated traits included chlorophyll a, chlorophyll b, carotenoids, soluble proteins, quantum yield of photosystem II, soluble sugars, proline content and grain yield. Analysis of variance was performed using statistical analysis system (SAS version: 9.3). The means were analyzed using the Duncan's test at 5% probability level.Results and discussionThe results showed that water deficit stress reduced the content of chlorophyll a (27%), chlorophyll b (32%), carotenoids (19%), soluble proteins (71%), quantum yield of photosystem II (28%), grain yield (33%) and in contrast, it increased the amount of soluble sugars (83%) and proline content (145%) compared to the control treatment. The slicing intersections of water deficit stress and cultivar showed that in terms of grain yield, Danko cultivar under irrigation conditions after 75 mm evaporation and Stratoskaya cultivar under irrigation conditions after 150 mm evaporation from the evaporation pan of Class A evaporation had the highest and lowest grain yields with 2414 and 1147 kg per hectare, respectively.ConclusionIn general, it can be said that under irrigation conditions after 150 mm evaporation Montanum cultivar because of more photosynthetic durability and better osmotic regulation than the other two cultivars had more tolerance to water deficit stress and it had higher grain yield.
Heavy metals
Faezeh Zaefarian; Maryam Sadegh; Roghayeh Hasanpour
Abstract
IntroductionCadmium (Cd) is the most mobile heavy element in the soil. This element in plants has a negative effect on the main function of the plant such as photosynthesis, cell proliferation, and water uptake by plant roots. Resistance adaptation of some plants allows them to store high concentrations ...
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IntroductionCadmium (Cd) is the most mobile heavy element in the soil. This element in plants has a negative effect on the main function of the plant such as photosynthesis, cell proliferation, and water uptake by plant roots. Resistance adaptation of some plants allows them to store high concentrations of heavy metals in their tissues without symptoms of poisoning, which eliminates them and revitalizes the environment. Corn (Zea mays L.) is able to continuously extract metals from contaminated soils by transferring them from roots to shoots. Corn was also a promising crop for phytoremediation due to its extensive root system, high biomass, and compatibility with cadmium soils. Also, legumes such as soybeans (Glycine max L.) can accumulate heavy metals in their tissue, and their interaction with B. japonicum is an important aspect influencing the behavior of soybeans under heavy metal stress. Mixed culture is a common cropping method that increases biomass. The use of this method in plants intended for plant extraction is of great importance because in contaminated soils it affects the uptake of heavy elements by plants. Therefore, due to the importance of soil contamination with heavy elements, this study was designed to investigate the effect of mono and mixed corn and soybean culture on cadmium contaminated soil.Materials and methodsThis experiment was performed in the greenhouse of Sari Agricultural Sciences and Natural Resources University as a factorial in a completely randomized design with four replications. The first factor of cadmium concentrations was 0, 50, 100, 150 and 200 mg kg-1. The second factor was corn and soybean cultivation ratios (maize in pure cultivation, soybean in pure cultivation, corn in mixed cultivation and soybean in mixed cultivation with a ratio of 50: 50). The seeds were planted in 5 kg pots. The density was four plants in the pot was considered. Two months after sowing, the plants were harvested. Pre-harvest measurement traits included plant height and stem diameter and post-harvest measurement traits included shoot dry weight, root dry weight, cadmium concentration of shoot and root, and cadmium concentration in soil.Results and discussionThe results showed that the concentration of cadmium in maize shoots in both mono-culture and mixed culture systems was higher than soybean and mixed cultivation, especially at high levels, increased the concentration of cadmium in maize and soybean shoots. Also, with increasing the levels of heavy metal, the concentrations of cadmium in the roots increased linearly in all culture systems. Maize had more ability to uptake and concentrate metals in its roots than soybeans, and mixed cultivation of maize and soybeans increased the concentration of cadmium in the roots of maize and soybeans. In this experiment. The highest concentrations of root cadmium in mixed maize and soybean crops were recorded 105.97 and 60.46 mg kg-1, respectively.ConclusionDry weight of maize and soybeans was lower in mixed than pure cultivation, which seems to be the main cause of the higher uptake of cadmium in plant organs under mixed culture conditions. In general, the ability of maize to phytoextraction is higher than soybeans due to its higher biomass.
Breeding plants for stress conditions
Hossein Sabouri; Mohammad Reza Jafarzadeh; Mahnaz Katouzi; Mohammad Reza Karim; Mohammad Javad Behrozbeh; Mohsen Rezaei; Ahmad Reza Dadras; Somayyeh Sanchouli
Abstract
IntroductionRice is one of the most important crops in Asian countries, which is cultivated in more than half of the continent's agricultural lands. Environmental conditions are different and uncontrollable even in different parts of an area, so the response of rice cultivars to these conditions will ...
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IntroductionRice is one of the most important crops in Asian countries, which is cultivated in more than half of the continent's agricultural lands. Environmental conditions are different and uncontrollable even in different parts of an area, so the response of rice cultivars to these conditions will be different. Therefore, it is necessary to perform performance comparison experiments to achieve high quality, quantity, consistency and stability in different regions. More than 50 percent of human food is supplied from cereals, and rice is a cereal that has a high crop after wheat, but more than wheat and others in terms of energy production per hectare Cereals are important. By using the GGE biplot method, by using multivariate methods, in addition to proper data analysis, the work facilitates the interpretation of the results. The aim of this study was to evaluate the stability of the lakes by using GGE biplot analysis and selecting and introducing superior lanes for stability and response in underwater stress conditions and flooding.Materials and methodsIn this experiment, the eight lines with the control cultivar of the region and IR29 cultivar during 2014 and 2015 with the desirable qualitative and qualitative characteristics and suitable growth period in a completely randomized block design with three replications in two regions of Gonbad Kavous and Ali-Abad were cultivated. Ten plants of 15 cultivated plants were randomly selected and separated from the soil at a depth of 50 cm. After removing the bushes from the soil using the shovelomics method, the plants were first immersed in water for seven days. Then the root and part of the air organs were separated. To record the root characteristics, each root of the plant is separated and the number of roots is less than 5 cm, the number of roots is 7-6 cm, the number of roots between 20-8 cm, the number of roots 21-30 cm and the number of roots greater than 30 cm, root volume and root dry weight were measured. Using the aerial parts, related traits such as panicle number, plant height, stem weight, straw weight, panicle length, number of filled grains, weight of grains and cluster number were recorded.Results and discussionThe results of analysis of variance showed that the difference between locations for days to days of traits, number of roots, total length of roots, root number between 7 to 20 cm, stem weight, panicle weight, root dry weight, straw weight and seed number Poke was significant, and the difference between years was significant for number of pancakes, root number was significant. Comparison of mean of studied sites and years showed that grain yield per hectare had no significant difference, but the mean comparison of this trait in terms of waterlogging and stress conditions indicated that flooding conditions had a higher yield than tension. Separation of the interaction of location × planting time × irrigation conditions with different cultivars by biplot method showed that the cultivar 87.5.103 in all states related to Aliabad city had the highest yield. In irrigation stress conditions, IR55411, IR70360, 87.5.21, IR66424 and 87.110 lines had lower yields, but in terms of flooding, IR55411, IR70360, 87.5.21, IR66424 and 87.110 lines had the highest yield, respectively. In both cases, all of the cultivars had a higher yield than IR-29ConclusionSeparation of the interaction of location × planting time × irrigation conditions with different cultivars by biplot showed that cultivar 87.5.103 in all states related to Aliabad city has the highest performance. In general, the cultivar 87.5.103 among all cultivars and the floodplain dome in the first year was the best environment for all the environments in terms of day.
Drought stress
Abdoulkarim Negari; Majid Jami Al-Ahmadi; Gholamreza Zamani
Abstract
IntroductionMedicinal plants contain rich storages of secondary metabolites or active compounds which are strongly affected by environmental factors, especially drought stress, and also by hormones and their derivatives. Thyme genus has more than 215 species in the world, of which 18 species have been ...
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IntroductionMedicinal plants contain rich storages of secondary metabolites or active compounds which are strongly affected by environmental factors, especially drought stress, and also by hormones and their derivatives. Thyme genus has more than 215 species in the world, of which 18 species have been identified in Iran. Thymus vulgaris is one of the main medicinal plants that is cultivated in the most countries. Its main components include Thymol and Carvacrol which have antibacterial, antifungal and antioxidant activity and these compounds can be effective in reducing the symptoms of COVID-19. The levels of moisture supply and elicitors like Coronatine (COR), Methyl Jasmonate (MJ) and Cyclodextrin (CYC) can be effective on the quantitative and qualitative yield.Materials and methodsThis investigation was conducted as split plot based on a randomized complete block design (RCBD) with three replications in the farm of Research Station of Khorasan Razavi Agricultural and Natural Resources Education and Research Center which is placed at 5th km Southeast of Mashhad in Iran. The main plots included three levels of moisture supply (at 40%, 65% and 90% field capacity (FC)) and the sub plots were elicitor levels included (1) control without elicitor, (2) 150 µM cyclodextrin (CYC) (3) 75 nM coronatine (COR) + 150 µM CYC (4) 150 nM COR + 150 µM CYC (5) 150 µM methyl jasmonate (MJ) + 150 µM CYC (6) 300 µM MJ + 150 µM CYC. The seeds were sowed in pro-trays which were filled from peat moss on 24 March 2019. After the germination, two seedlings were held in each cell of portray for transplanting to the field. The seedlings were transplanted to each point of cultivation on 24 May 2019. The treatments of the moisture supply were applied 45 days after transplanting the seedlings. In order to apply moisture treatments, at the first, FC was determined by farm and pressure plate method. With sampling the soil of plots (mean of two sample 0-15 cm and 15-30 cm) for several times, was determined the irrigation date. Elicitor treatments were applied two times; the first was 45 days after transplanting and the second was two months later. The plants were harvested two weeks after the last elicitor spraying.Results and discussionThe largest crown diameter was observed in interaction of elicitor treatments and the levels of moisture supply at 90% FC.The highest leaf proline content (from 5.5 to 5.8 µmol g-1 fresh leaves) was observed in interaction of 4 levels with elicitor treatment (levels 3, 4, 5 and 6) at the level of moisture supply 40% FC that placed in one group. The highest and lowest electrolyte leakage (47.6% and 22.1%, respectively) were related to interaction of the control treatment at the level of moisture supply of 40% FC and the treatment of 150 μM MJ + 150 μM CYC at the level of moisture supply 90% FC. The highest yield of dry herb and leaves and essential oil (5.64 and 3.2 t ha-1 and 65.9 kg ha-1 respectively) was obtained under moisture supply at 90% FC. Except the percentage of essential oil, there was a significant correlation between all measured traits including crown diameter, height, electrolyte leakage, proline content, relative water content of leaf, fresh and dry yield of herb, dry leaf and stem yield and essential oil yield. Although the interaction of the treatments affected some physiological traits, but the quantitative and qualitative yield of the plants were affected by moisture levels.ConclusionAs a result, drought stress and elicitors can effect on plant performance; morphological, physiological and chemical dynamics. In this study, suppling moisture levels had an impotent effect on biological yield and this indicator caused to increase essential oil yield. Elicitors and interaction of treatments had a significant effect on some physiological characteristics.
Drought stress
Vafa Torfi; Abdolrazagh Danesh Shahraki; Mahdi Ghobadinia; Keramatollah Saeidi
Abstract
IntroductionLemon balm (Melissa officinalis L.) is one of the most important plants in family Lamiaceae that is involved in the treatment of diseases such as insomnia, anxiety, depression, neurological diseases, migraine, nervous disorders of the stomach. The most antioxidant activity of the plant was ...
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IntroductionLemon balm (Melissa officinalis L.) is one of the most important plants in family Lamiaceae that is involved in the treatment of diseases such as insomnia, anxiety, depression, neurological diseases, migraine, nervous disorders of the stomach. The most antioxidant activity of the plant was related to leaves, stems and flowers, respectively. The essential oil of lemongrass leaves had more antioxidant activity than stem and flower essential oils. Nowadays, drought stress is considered as the most important factor in reducing production, especially in arid and semi-arid regions. Given the importance and role of medicinal plants in various industries, a significant point in the production of these plants is to increase their biomass production without the use of chemical inputs, especially in drought stress. It seems that application of plant growth promoting bacteria has positive effect on the yield and quality of medicinal plants under biological and non-biological stress conditions. Therefore, the present study was designed and conducted to investigate the effect of some plant growth-promoting bacteria on agromorphological traits of Lemon balm (Melissa officinalis L.) in water deficit conditions.Materials and methodsThe factorial pot experiment was performed in a randomized complete block design with three replications in the open area of the research greenhouse of Shahrekord University, Faculty of Agriculture during 2009-2010 growing season. The experimental factors were water deficit stress at three levels (full irrigation, 75% and 50% of full irrigation) and bacterial inoculation treatments at eight levels (non-bacterial inoculation as control treatment, separate inoculation of Bacillus licheniformis, Bacillus megaterium and Pseudomonas putida, bacterial inoculation of B. licheniformis * B. megaterium, P. putida * B. megaterium and B. licheniformis * P. putida as dual inoculation and bacterial inoculation of P. putida * B. licheniformis * B. megaterium as triple inoculation). After harvest, plant height, leaf dry weight, stem dry weight, biological yield, root dry weight and root volume were measured. Leaf area was also measured using Digimizer software. Analysis of variance using SAS software, comparison of means by LSD test at 5% probability level and drawing graphs with Excel software were performed.Results and discussionThe results showed that the main effects of different levels of water deficit stress on all studied traits except plant height were significant at the level of 1% probability. So that water stress at the level of 100% full irrigation increased plant height, leaf dry weight, stem dry weight, root dry weight, biological yield, leaf area and water use efficiency compared to 50% of full irrigation by 17.6%, 124.5%, 79.1%, 65.6%, 102%, 384.4% and 43% respectively. The main effects of bacterial inoculation treatments on plant height, leaf dry weight, biological yield, leaf area, root dry weight, proline content and water use efficiency were significant at 1% probability level and on root volume at 5% probability level, while on dry stem weight trait no significant effect. Interaction effects of bacterial inoculation treatments and different levels of water deficit stress on leaf area, root dry weight, root volume and proline content at 1% probability level, on leaf dry weight, biological yield and water use efficiency at 5% probability level were significant and on plant height and stem dry weight had no significant effect.ConclusionAccording to the results, all bacterial inoculation treatments in non-stress conditions were able to improve the studied traits, effectively while in stress conditions, bacterial inoculation treatments at 75% stress and 50% irrigation levels, except in plant height and water use efficiency and proline content at 50% irrigation level had no significant effect on other traits.
Salinity stress
Alireza Mohseni Mohammadjanlou; Raouf Seyed Sharifi; Saeid Khomari
Abstract
IntroductionSalinity is one of the important and adverse environmental constraints restricting growth and development of plant particularly in arid and semiarid regions. Soil salinity induces water stress, nutritional imbalance, hormonal imbalance and generation of reactive oxygen species (ROS) which ...
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IntroductionSalinity is one of the important and adverse environmental constraints restricting growth and development of plant particularly in arid and semiarid regions. Soil salinity induces water stress, nutritional imbalance, hormonal imbalance and generation of reactive oxygen species (ROS) which may cause membrane destabilization. Moreover, it decreases the yield of many crops by inhibiting plant photosynthesis, photosystem II efficiency (Netondo et al., 2004), protein synthesis and lipid metabolism. One approach to solve the salt stress problem is the use of plant growth promoting rhizobacteria (PGPR) and mycorrhiza. Seyed sharifi et al, (2016) reported that inoculation with PGPR enhanced proline content, relative water content, and photochemical efficiency of PSII and the activity of antioxidant enzymes of wheat under salinity stress. Large number of plant species are capable of forming symbiotic associations with arbuscular mycorrhizal fungi (Glassop et al., 2005). They also impart other benefits to them, including production/accumulation of secondary metabolites, osmotic adjustment under osmotic stress, enhanced photosynthesis rate and increased resistance against biotic and abiotic stresses. In recent years, the use of growth regulators such as polyamines has been proposed to reduce the effect of biotic and abiotic environmental stresses (Kusano et al., 2008). Therefore, the aim of this study was to evaluate the effects of bio-fertilizers and putrescine on some physiological and biochemical responses of wheat under salinity stress conditions.Materials and methodsA factorial experiment based on randomized complete block design with three replications was conducted under greenhouse condition in 2018. Experimental factors were included soil salinity in f0ur levels [no-salt (S1) or control, salinity 40 (S2), 80 (S3) and 120 (S4) Mm NaCl], bio fertilizers at four levels [no bio fertilizer (B1), both application Psedomunas Putida Strain 186 and Flavobacterim Spp (B2), both application of mycorrhiza with Psedomunas and Flavobacterim (B3), application of mycorrhiza (Glomus Intraradices) (B4)] and putrescine foliar application in three levels (without putrescine as control (P1), foliar application of 0.5 (P2) and 1 (P3) mM). Air temperature ranged from 22°C to 27°C during the day and 18–21°C during the night. Humidity ranged from 60-65%. The wheat cultivar Gascogen was used in the experiment. Salt stress treatments were applied in two stages (3 - 4 leaf stage and two weeks after the application of the first salinity). Foliar application of putrescine was conducted in two stages of vegetative growth (4–6 leaves stage and before of booting stage).The trend of changes in flag leaf chlorophyll index at the stage of flag leaf emergence, in three samples of flag leaf were measured by chlorophyll meter (SPAD-502 Minolta of Japan). Chlorophyll fluorescence, also at the stage of flag leaf emergence, in three samples of flag leaves in each pot was randomly selected (in the period of 8-10 am) and by the device (chlorophyll fluorometer; Optic Science-OS- 30 USA) After 30 minutes of darkening by clips, F0, Fm and Fv/Fm indices were measured (Seyed Sharifi et al., 2016). The flag leaf was used to measure malondialdehyde (MDA) based on Stewart and Boley method (Stewart and Bewley, 1980) and method of Alexieva et al, (2001) was used to measure the hydrogen peroxide. In order to measure grain yield, 5 plants of each pot randomly were harvested. Analysis of variance and mean comparisons were performed using SAS9.1 computer software packages. The main effects and interactions were tested using LSD test at the 0.05 probability level.Results and discussionThe results showed that under soil salinity, both application of mycorrhiza with Psedomunas and Flavobacterim and foliar application of 1 mM putrescine increased maximum fluorescence, quantum yield, SPAD, yield and yield components. Also, both application of mycorrhiza with Psedomunas and Flavobacterim and foliar application of 1 mM putrescine increased about 28.57% from grain yield in comparison with no application biofertilizer and putrescine under the highest salinity level. Salinity increased malondialdehyde (MDA) and hydrogen Peroxide (H2O2), whereas application of bio fertilizers and putrescine under salinity conditions decreased (MDA) and (H2O2). both application of mycorrhiza with Psedomunas and Flavobacterim and foliar application of 1 mM putrescine under the highest salinity level decreased malondialdehyde and hydrogen peroxide 32% and 35.31% respectively, in comparison with no application biofertilizer and putrescine in same salinity level.ConclusionIt seems that bio fertilizers and putrescine application can increase grain yield of wheat due to improvement of agrophysiological and biochemical traits under soil salinity conditions.
Drought stress
Nasim Solat Petloo; Rasool Asghari Zakaria; Asghar Ebadi; Parviz Sharifi Ziveh
Abstract
IntroductionThe cow cockle (Vaccaria hispanica (Mill.) Rauschert) is an annual plant of the Caryophyllaceae family with a chromosome number of (2n=2x=30). This plant grows upright to a height of 30 to 100 cm with several branches and has great potential for producing medicinal products due to its triterpenoid ...
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IntroductionThe cow cockle (Vaccaria hispanica (Mill.) Rauschert) is an annual plant of the Caryophyllaceae family with a chromosome number of (2n=2x=30). This plant grows upright to a height of 30 to 100 cm with several branches and has great potential for producing medicinal products due to its triterpenoid saponins. In arid and semi-arid regions, plants experience periods of lack of moisture during their growth period and must be able to tolerate these periods to produce a proper yield. This experiment was aimed at investigating the drought stress responses of different V. hispanica ecotypes and evaluating their drought stress tolerance.Materials and methodsThis experiment was performed as a split-plot experiment based on a randomized complete block design with three replications in 2020-2021 at Parsabad Agricultural Station. The main plots were allocated to three treatments of non-stress, moderate and severe stress (irrigation cycles of 7, 10, and 14 days, respectively), and sub-plots were assigned to eight native cow cockle ecotypes collected from different northwestern regions of Iran. Seeds were sown directly in the soil at a rate of 5.5 to 8 kg per hectare with a depth of 1-2 cm, and a row spacing of 20 cm. Irrigation operations were performed similarly for all experimental units up to the beginning of stem elongation, after which the irrigation intervals for applying stress were increased. At maturity, seed yield, biomass, and harvest index were recorded and various tolerance and sensitivity indices were calculated using the yield of each ecotype under non-stress conditions (Yp) and stress conditions (Ys).Results and discussionThe results of the analysis of variance showed that the effects of irrigation regime, ecotype and their interaction were significant in terms of seed yield, biological yield and harvest index. Ecotype 6 had the lowest decrease in grain yield per unit area and harvest index under stress conditions. In terms of yield stability and drought tolerance indices, harmonic mean yield, geometric mean yield and mean productivity, the lowest values in moderate and severe stress conditions were related to ecotypes 7 and 1, respectively, and the highest values of these indices were related to ecotype 6 in both stress conditions. Estimation of SIIG index for different ecotypes showed that ecotype 6 had the highest amount of the SIIG in both moderate and severe stress conditions. Ecotypes 4 and 3 in moderate and severe stress conditions were in the next rank and were classified as ecotypes with relatively high drought tolerance. In moderate stress conditions, ecotypes 7 and 8 and in severe stress conditions, ecotypes 1 and 7 with the lowest SIIG showed high sensitivity to drought stress. Factor analysis based on principal component analysis (PCA) showed that the first two factors with specific values greater than one, in both moderate and severe stress conditions had 95.58% and 97.18% of the total variance, respectively. According to the MGIDI index, in moderate stress conditions, ecotype 6 had the lowest value and was considered the most tolerant ecotype to drought stress, followed by ecotypes 4 and 3. In severe stress conditions, after ecotype 6, ecotypes 3 and 4 were in the next rank.ConclusionEstimation of the ideal genotype selection index (SIIG) and the multi-trait genotype–ideotype distance index (MGIDI) for different ecotypes based on all tolerance indices showed that ecotype 6 had the highest SIIG and the lowest MGIDI in both stress conditions followed by ecotypes 4 and 3. Ecotypes 1, 7, and 8 with the lowest SIIG and the highest MGIDI showed high sensitivity to drought stress. Therefore, among the studied ecotypes, ecotype 6 can be considered as the most tolerant ecotype to drought stress. At all, it can be concluded that the studied ecotypes have sufficient genetic diversity to be used in breeding programs with the aim of obtaining lines with higher tolerance to drought stress. The use of SIIG and MGIDI indices in crop selection programs can also be considered more.
Drought stress
Zenab Ramazan por; Tooraj Mir Mahmoodi; Saman Yazdan Seta
Abstract
IntroductionDrought stress, permanent or temporary, limits the growth and the distribution of natural vegetation and the production of cultivated plants more than any other environmental factor. Water deficit stress has changed plants ‘metabolism significantly, by attenuating the growth, photosynthesis, ...
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IntroductionDrought stress, permanent or temporary, limits the growth and the distribution of natural vegetation and the production of cultivated plants more than any other environmental factor. Water deficit stress has changed plants ‘metabolism significantly, by attenuating the growth, photosynthesis, and ultimately yield of the plants. The recent global trend in production of medicinal plants is in favor of sustainable agriculture. One of the efficient practices of sustainable agriculture is the application of biological fertilizers for quantitative and qualitative yield improvement in medicinal plants, such as fennel, which is of great significance in food, pharmaceutical, and cosmetic industry. Fennel (Foeniculum vulgare Mill.) is an umbelliferous plant. Due to the high potential of West Azerbaijan province, especially Mahabad region, the present study was conducted to investigate the effect of biofertilizers on the increase of water tolerance in fennel.Materials and methodsIn order to investigate the effect of different irrigation regimes and biofertilizers on the quantitative and qualitative characteristics of fennel, an experimental experiment was conducted in 2020 in an agricultural farm in Mahabad city. In this experiment, four irrigation regimes (irrigation after 60, 90, 120 and 150 mm evaporation from Class A evaporation pan) in main plots and inoculation of seeds with biofertilizers (including control, inoculation with mycorrhiza, azotobacter and phosphate Fertile 2) were placed in subplots. In this study, plant height, number of sub-branches, number of umbrellas and umbrellas per plant, number of seeds per umbel, thousand kernel weight, biological yield, grain yield, essential oil content, phenol and flavonoid content were measured. The data obtained from the experiment were analyzed using SAS 9.2 software. The means obtained were statistically compared using Duncan's test at a level of 5% probability.Results and discussionBased on the results of the analysis of variance of the data, a significant difference was observed between the levels of the irrigation regime in terms of the effect on all the studied traits at the level of 1% probability. Effect of biofertilizer on the number of branches, number of umbrellas per plant, number of umbrellas per umbrella, on thousand kernel weight, biological yield, grain yield, percentage of essential oil, total phenol content and flavonoids at a probability level of 1% and on plant height, number of seeds per umbel and flavonoid content were significant at 5% probability level. Among of irrigation with biofertilizer interaction treatments in terms of effect on plant height, number of sub-branches, number of umbrellas per plant, number of umbrellas per umbrella, number of seeds per umbrella, grain yield, essential oil percentage and phenol content at a probability level of 1% and in terms of effect on thousand kernel weight there was a significant difference at the level of 5% probability. The results showed that the highest plant height, number of sub-branches, number of umbrellas per plant, on thousand kernel weight and grain yield were allocated to irrigation regime after 90 days and seed inoculation with mycorrhiza, Also, the highest percentage of essential oil and total phenol content in the irrigation regime was observed after 120 mm of evaporation and inoculation of seeds with mycorrhiza. The results of mean comparisons also showed that although grain yield decreased with increasing severity of water deficit stress, but in all irrigation regimes, the use of biofertilizers significantly increased grain yield compared to the control treatment. Also, the use of biofertilizers under irrigation regime stresses after 120 and 150 mm of evaporation was able to show higher grain yield than the control treatment in irrigation regimes after 60 and 90 mm of evaporation. In this study, water deficit stress increased the percentage of essential oil in fennel plant. Also, the use of mycorrhiza in irrigation regimes after 60 and 90 and the use of mycorrhiza and Azotobacter in irrigation regimes after 120 and 150 mm of evaporation significantly increased Essential oil percentage compared to control treatment.ConclusionIn this study, the most suitable quantitative and qualitative characteristics of fennel were obtained in the irrigation regime after 90 mm, so the irrigation regime is recommended to achieve the maximum quantitative and qualitative characteristics of fennel in the study area. The results also showed that the application of Mycorrhiza and Azotobacter biofertilizers in both normal irrigation and water deficit conditions can improve the quantitative and qualitative properties.
Breeding plants for stress conditions
Hossein Nazary; Mozaffar Rostaii; Seid Mohammad Alavi Siney
Abstract
IntroductionDrought is recognized as one of the most common and challenging environmental stresses in agriculture worldwide (Hu et al., 2020) and the production of this plant Reduces by 21%. Annual production of 13.7 million tons with a cultivated area of 5.8 million hectares in Iran shows the importance ...
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IntroductionDrought is recognized as one of the most common and challenging environmental stresses in agriculture worldwide (Hu et al., 2020) and the production of this plant Reduces by 21%. Annual production of 13.7 million tons with a cultivated area of 5.8 million hectares in Iran shows the importance of this plant. Of this level, 67% is related to rainfed cultivation and the rest to irrigated cultivation. Numerous studies have been conducted to investigate the traits and determine their relationship with wheat grain yield using multivariate methods (Alavi-Siney and Saba, 2015). In most of these studies, the relationship between traits and grain yield has been discussed, but there has been no discussion about the selection of superior genotypes. Therefore, a method is needed to be able to select the desired genotypes according to all of studied traits. The Selection Index for Ideal Genotype (SIIG) is one of the methods that in addition to selecting the ideal genotype that can determine the distance between genotypes. In this method, it is possible to identify genotypes with the desired characteristics. The aim of this study was to investigate different wheat genotypes under rainfed conditions and determine the best genotypes in terms of yield and early maturity through SIIG selective method.Materials and methodsIn this study, 24 bread wheat genotypes (21 lines and Baran, Sadra, Hashtrood cultivars) were carried out in a randomized complete blocks design with four replications at the rainfed research station of Zanjan Agricultural and Natural Resources Research Center located in Khodabandeh for three years. In this experiment, 5 morpho-phenological traits were measured as follows. Plant height (PLH), days to heading (DHE), days to maturity (DMA), 1000-seed weight (TGW) and grain yield (YLD) were measured after physiological maturation. Analysis of variance, comparison of mean traits by LSD method and matrix of phenotypic correlation coefficients were performed using SAS software (9.4). SPSS software (21) was used to group the genotypes by cluster analysis through Ward method. Multivariate analysis of variance was performed to investigate the differences between clusters and compare the mean between clusters using SPSS software (21). In order to study the genetic diversity and integration of morpho-phenological traits, SIIG method was used (Zali et al., 2015).Results and discussionThe results of analysis of variance showed a significant difference between the genotypes, indicating sufficient diversity in terms of the studied traits. The matrix of correlation coefficients showed a positive and significant relationship between1000 grain weight, grain yield and SIIG index. In addition, a negative and significant relationship was observed between days to heading with 1000 grain weight, grain yield and SIIG index. Grouping of genotypes using cluster analysis and multivariate analysis of variance showed that genotypes 4, 12, 16, 17, 18, 22 and 23 have the highest value in terms of most traits, especially grain yield. Grouping of genotypes based on SIIG index also placed 7 genotypes (6, 10, 12, 16, 17, 18 and 23) in the top group. Comparison of the two methods showed that 5 genotypes are common in the last two methods, which indicates the high efficiency of these methods in selecting the best. The advantage of SIIG method over other methods is the grouping of genotypes based on the desirability of traits; for example, the low average of genotypes in days to heading and days to maturity traits are desirable, which in this method is considered. This is not considered in multivariate analyzes such as cluster analysis. Therefore selected genotypes through the SIIG index as superior genotypes during three years of experiment are recommended for use in rainfed breeding programs.ConclusionAccording to the ranking based on SIIG index and comparison with control cultivars, genotypes No. 6, 10, 12, 16, 17, 18 and 23 can be recommended as superior genotypes for use in breeding programs under rainfed conditions.
Drought stress
Sajjad Nasiri; Babak Andalibi; Afshin Tavakoli Zaniani; Mohammad Amir Delavar
Abstract
IntroductionBarley (Hordeum vulgare L.) is among the most important cereal crops and large portions of human populations in many parts of the world depend on them as a source of food and animal feed. Drought is one of the most important environmental stresses which affects ...
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IntroductionBarley (Hordeum vulgare L.) is among the most important cereal crops and large portions of human populations in many parts of the world depend on them as a source of food and animal feed. Drought is one of the most important environmental stresses which affects yield and yield components of plants significantly which plants respond and adapt to drought stress by means of various morphological, biochemical and physiological changes. Nowadays Biochar has been employed for scientific and commercial usage as a soil amendment for improving the productivity of crops. Results of researchs showes that Biochar makes a great contribution in crop plant's growth. For instance investigations showed that drought stressed chickpea plants exhibited considerable reduction in uptake of nitrogen and phosphorous which was ameliorated by Biochar treatments. Jasmonic acid (JA) and its methyl ester, methyl jasmonate (MeJA) are important cellular regulators involved in many growth, developmental and physiological processes. It was found that exogenous application of MeJA improved tolerance to drought, salinity, chilling (Rehman et al., 2018) and heavy metal stresses in different plant species.Materials and methodsIn order to investigation of the impacts of different levels of mineral biochar and methyl Jasmonate on growth, yield and yield components of spring barley under different levels of drought stress a factorial experiment in randomized complete block design in pots in 5 replications was done in 2019-2020 at the experimental field of university of Zanjan. Reviewed factors included in three levels of drought stress (100% FC as the none stressed, 60% FC as the mild stress and 30% FC as the severe stress), biochar application before cultivation in three levels (without biochar, 1.5% and 3% of the soil weight) and foliar spraying of methyl Jasmonate in three levels (0, 75 and 150 μmol per liter Studied factors included electrolyte leakage, proline and photosynthetic pigments concentration, water use efficiency, relative water content and economical yield.Results and discussionResults showed a significant impact of used treats on most of the characteristics. All studied factors in this experiment including WUE, RWC, proline, EL, photosynthetic pigments and yield were affected by drought stress but 1.5% biochar and 75 μmole per liter methyl Jasmonate resulted in enhancement of studied factors of stressed plants both in 60% of FC and in 30% of FC in comparison to untreated plants. But increasing in usage of these materials didn’t have any positive impact on studied plants. The highest economical yield was obtained in normal irrigation circumstance with foliage application of 75 μmole per liter of methyl jasmonate and using 1.5% of biochar per soil weight and the lowest yield was obtained when we used 30% of field capacity in irrigation without using methyl jasmonate.ConclusionWe can find out from these results that as a whole drought in middle and severe levels can be disastrous for both morphological and physiological characteristics of every plant which results in reduction in economical yield. But it's necessary to mention this point that using stress moderator materials whether materials which are used in soil like Biochar or plant growth regulators like methyl Jasmonate which are known as the anti stress substances cause moderation in the catastrophic effects of drought stress which through enhancing some indexes like the relative water content and ameliorating of water use efficiency in comparison to untreated plants with these materials can diminish the severe impacts of stress and eventually through boosting economical yield can dwindle damages of drought. Nevertheless it's absolutely comprehensible from the results of the experiment that using too much of these materials not only do not have any positive effect on growth, physiological or biochemical indicators under drought stress but also can reduce these characteristics even to lower than their quantity in untreated plants.
