Saeid Yarahmadi; Ghorban Ali Nematzadeh; Hossein Sabouri; Hamid Najafi Zarrini
Abstract
Introduction Drought is the most common abiotic stress in crops. The study of agro-morphological traits and their relation to grain yield can be helpful in determining the most important agro-morphological traits affecting grain yield and their use in indirect selection. As the water resources available ...
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Introduction Drought is the most common abiotic stress in crops. The study of agro-morphological traits and their relation to grain yield can be helpful in determining the most important agro-morphological traits affecting grain yield and their use in indirect selection. As the water resources available for agriculture become more limited, developing drought tolerant lines is significantly important. The purpose of this study was to identify the most important traits affecting grain yield in rainfed conditions and to use these traits in clustering to identify the best genotypes for introducing or conducting crosses to create new breeding populations.Materials and methodsThis research was carried out to investigate the relationship between agronomic traits and yield using 132 spring wheat genotypes in alpha-lattice design with two replications at the Agricultural Research Station of Gonbad-e-Kavos. Pedigree information is available on the CIMMYT Web site (http://orderseed.cimmyt.org/iwin/iwin-fb-table.php). Each replicate contained 12 blocks, and in each incomplete block, 11 genotypes were placed. Each variety was cultivated in four lines with a length of 1 meter and 0.2 meter lines spacing. Each plot was planted based on seed rate of 140 kg ha-1. Cultivation was carried out in rainfed condition. Characteristics of grain yield (g/m2), biomass (g), harvest index, number of spikes, height (cm), days to heading, days to maturity, grain filling duration, seed filling rate (g/m2/day), Flag leaf area (cm2), flag leaf specific area (cm2/g), leaf dry weight (g), 1000 grain weight (g), spike length (cm), spike weight (g) and grain weight per spike (g) were evaluated for all genotypes.Results and discussion The highest correlation was observed respectively between yield with seed filling rate (0.839), harvest index (0.838), biomass (0.858), 1000 grain weight (0.579), grain weight per spike (0.437), and weight of the spike (0.409). Yield had a negative and significant correlation with days to maturity (-0.566) and days to heading (-0.446). The negative and significant correlations between yield under rainfed conditions and days to maturity are a mechanism for avoiding drought stress at the end of the season. The genotypes that earlier complete their physiological maturity could run away from drought stress at the end of the season and do not face stress. Seed filling rate and days to heading were introduced into the model as important traits affecting grain yield. These traits account for 78.1% of the variation in yield. Path analysis indicated that seed filling rate had the most direct effect on yield (0.773). Also, the days to heading had a direct effect of -0.285 on performance. Cluster analysis in this study was conducted with the aim of grouping the studied genotypes in terms of performance related traits. Group 5 and 7 were superior to other groups in terms of traits. The yield of genotypes No. 38, 39 and 52 was 572.5, 578.3 and 535.8 g/m2, respectively. Genotype No. 20 earlier heading than other genotypes. This genotype ranked second among the other genotypes for days to maturity. Therefore, this genotype has the ability to escape from the end-season stresses. Genotype No. 39 had the highest 1000 grain weight and the highest grain weight per spike. Conclusions None of the genotypes in Group 5 or 7 were superior to all performance related attributes. Therefore, in order to aggregate the characteristics associated with performance in a genotype, crossing of several genotypes and the production of breeding populations using these crosses should be used. Genotypes No. 20, with the least days to heading and the least days to maturity, genotypes No 12, 38, 39, 52, 67 and 85 with high seed filling rate and genotypes No. 103, 85, 39 and 20 with the highest thousand seed weight for Crossings and production of breeding populations can be used. It is suggested that a research be carried out in a few years using genotypes in groups 5 and 7 to select the best genotypes among them more confidently.
Leila Akbari; Sohbat Bahraminejad; Kianoosh Cheghamirza
Abstract
IntroductionWheat is the main source of nutrition for about 85% people of the world. On the other hand, drought is one of the most damaging abiotic stresses leading limitation to food supply in the worldwide and decreases crops yield more than any other environmental factor especially in Iran. Study ...
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IntroductionWheat is the main source of nutrition for about 85% people of the world. On the other hand, drought is one of the most damaging abiotic stresses leading limitation to food supply in the worldwide and decreases crops yield more than any other environmental factor especially in Iran. Study of physiological reactions and traits in wheat could be useful in identifying effective mechanisms to increase resistance to undesirable environmental conditions and to promote yield performance under drought stress condition. The purpose of the present study was to investigate the genetic inheritance and type of gene action in the control of physiological traits in bread wheat to progress breeding programs in order to increase the yield under both normal and drought stress conditions. Materials and methodsGene action could be studied using the generation means analysis (GMA). Generation mean analysis was performed using Mather and Jinks method (1982). The seeds of six populations (P1, P2, F1, F2, BC1:1 and BC1:2) for each cross (totally 11 treatments) were planted in a randomized complete block design with three replications. The parental genotypes used in this study were: “Winter B. C. of Roshan”, “Parsi”, “Sistan”. The crosses, “Parsi × Winter B. C. of Roshan” and “Sistan × Winter B. C. of Roshan” were made in 2014-2015. The experiment was conducted under two normal and water-deficit stress conditions in 2015-2016. Different traits including, grain yield, total chlorophyll content, chlorophyll a, chlorophyll b, leaf area index, leaf temperature, relative water content, stomatal conductance, persistence indicator and photosystem II maximum efficiency were measured. Broad-sense inheritability was calculated according to following formulas; h_b^2 = [V_(F_2 ) – (V_(P_1 ) × V_(P_2 ))1/2] / V_(F_2 ) h_b^2 = (V_(F_2 ) – V_(F_1 )) / V_(F_2 ) h_b^2 = [V_(F_2 ) – (V_(P_1 ) × V_(P_2 )×V_(F_1 ))1/3] / V_(F_2 ) h_b^2 = (V_(F_2 ) – VE) / V_(F_2 )VE = [V_(P_1 )+ V_(P_2 )+ (2V_(F_1 ))] / 4 Narrow-sense inheritability was calculated according to Warner (Warner, 1952) as follows:h2n=[2 VF2- (VBC2 + VBC1)/ F2Analysis of variance and mean comparison of the characters were performed using SAS Software. Generation mean analysis was carried out only for those traits that showed significant differences among generations. Results and discussionThe results showed that grain yield decreased in both of crosses due to water-deficit stress. In general, “Parsi” showed a higher reduction in grain yield when compared to the “Winter B. C. of Roshan”. In normal condition of both crosses (“Parsi × Winter B. C. of Roshan” and “Sistan × Winter B. C. of Roshan”), the highest amount of narrow-sense heritability (h_n^2 ) belonged to chlorophyll b content (52% -53%), leaf area index (50-58%) and total chlorophyll content (45-63%), respectively. In water-deficit stress condition for the first population, the highest amount of narrow-sense heritability (h_n^2 )belonged to the content of chlorophyll b (61%), leaf area index (54%) and total chlorophyll content (68%), and in the second cross it belonged to content of chlorophyll a (78%) and leaf area (56%). The differences among generation was not significant for grain yield in both crosses in different conditions except for the cross “Sistan× Winter B. C. of Roshan” in normal condition. The genetic analysis for this trait showed that the additive component was not significant but dominant component was highly significant which indicating that conventional selection may not be effective for the improvement of the trait and therefore for the selection for this trait suggested to be postponed to the later generation. ConclusionsThe high amount of narrow-sense heritability for chlorophyll b content, leaf area index and total chlorophyll content illustrates that additive effects play a big role to control them. Therefore, selection method could be effective method to improve the mentioned traits in breeding programs.
Hajar Hosseini; Omidali Akbarpour; payam pezeshkpour
Abstract
Introduction The main objective in breeding programs is mainly based on evaluation experiments to select superior genotypes and accurate estimates of the mean of varieties of different varieties. Soil fertility, soil water-holding capacity, soil physical and mineral characteristics, wind direction and ...
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Introduction The main objective in breeding programs is mainly based on evaluation experiments to select superior genotypes and accurate estimates of the mean of varieties of different varieties. Soil fertility, soil water-holding capacity, soil physical and mineral characteristics, wind direction and other unknown agents are often varied across an experimental site. This means that that the residuals of conventional models such as RCB are not independent of their near plots or spatial locations. So, this is an inherent issue which spatial adjustment of errors necessarily improves the precision of estimated treatment. The main objectives of this paper were to (1) explore the characterization of spatial dependence of traits using linear mixed models in large field chickpea trials in normal and drought conditions, (2) compare the efficiency of statistical analysis of spatial model to RCB model, (3) estimation of genetic parameters based on spatial models. Materials and methods This research was carried out in order to evaluate the yield and yield components of 64 chickpea genotypes in normal and rainfed conditions in Khorramabad Province, Iran. Experiments were conducted in an 8 × 8 Lattice square design framework in two replications for each condition during the 2018 season. Due to seasonal precipitation, there was no significant statistical difference between rainfed and normal conditions as well genotype by environment interaction in most of the traits. Therefore, rainfed data were considered as replications for the normal environment in all traits and all replications were subjected as one condition. To analyze the data for removing heterogeneity of farm condition in Lattices square design, Federer's spatial models were used to optimize the Lattice square linear model. Finally, the nearest neighbor model was selected as the best model based on the relative advantage and also the statistic -2RLL. Results and discussion The results of the combined analysis of variance of chickpea genotypes in two normal and dry conditions were shown in Table 2. These results showed that there was no significant difference between two normal and dry conditions in all traits except for pod weight and root dry weight. These results indicated that the two environments provided the same conditions for the genotypes on average. Also, the interaction of genotype in the environment was not statistically significant in all traits. After integrating the normal and dry data, the analysis of variance was carried out using randomized block design and lattice approach on data. The results showed that the spatial model (4), the nearest neighbor model, is the best linear model for analyzing and comparing the mean of genotypes. This model had the lowest -2RLL (-2 Res Log Likelihood). The lower the value of this statistic, the better the adequacy of the model to justify the response variable. Analysis of variance by the nearest neighbor method for different traits was shown in Table 4. The significant differences existed among genotypes in all traits except for pod weight and root dry weight at the 0.01probability level. Estimation of heritability of different traits showed that most of the studied traits had a heritability ranged from 0.39 to 0.75. For the grain yield traits with 10% intensity selection, the predicted genetic gain was 14% relative to the trait average. Therefore, this genetic gain can be used to advance the development of this trait. Also, genotypes G59, G09, G12, G30, and G41, respectively, in the nearest neighbor model, had the highest ranked estimated grain yields. Conclusions The results of the analysis of the nearest neighbor model showed that there was a significant difference between all genotypes for all traits, as well as high genetic variance and acceptable heritability. Therefore, the variation in the genotypes studied could be used and introduced superior genotypes for breeding programs and even introductions to farmers.
Seyed Poriya Darbani; Ali Ashraf Mehrabi; Seyyed Saeid Pourdad; Abbas Maleki; Mohsen Farshadfar
Abstract
Introduction Sunflower is known as the world's second largest hybrid plant and it is the fifth important oil plant in the world. Having of high percentage of unsaturated fatty acids along with a significant amount of protein (about 07-27%) increase the nutritional value of this oil seed. Drought stress ...
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Introduction Sunflower is known as the world's second largest hybrid plant and it is the fifth important oil plant in the world. Having of high percentage of unsaturated fatty acids along with a significant amount of protein (about 07-27%) increase the nutritional value of this oil seed. Drought stress is one of the main challenges for global crop production. So that about 40% of the world's land is located in arid and semi-arid regions and in these areas, water is the main limiting factor for production. In Iran, the limitation of water resources and the shortage of precipitation is a major challenge for crop cultivation. Thus, evaluation of response of different genotypes of a crop to deficit irrigation conditions and selection of more tolerant genotypes as well as improving advanced and resistant cultivars for arid and semi-arid regions, can achieve higher yields and more crop productions. In sunflower, despite there are deep and wide roots, the intense moisture stress significantly reduces the diameter of head, the number of seeds per head and the seed yield. Therefore, the aim of this study was to investigate the responses of sunflower genotypes under water stress conditions in order to select the superior genotypes under this stress. Materials and methods The present study was carried out to identify sunflower tolerant genotypes at Research Station of Dryland Agricultural Research Institute (Sararood) in Kermanshah. The experiment was carried out in the form of a lattice square design. In this study, 64 sunflower genotypes with 8 x 8 arrangement were compared in two conditions of non-stress and applying water stress (irrigation cut off at flowering stage). At the end of growing season, five plants per plot were harvested and after transferring them to the laboratory, traits of head diameter, number of seeds per head and weight of 1000 seeds were measured. In the bottom half of each plot that was dedicated to yield evaluation, the plants were harvested after removing the margin and counting the number of heads per m2 and then, after separation of seeds, seed yield of genotypes were measured, separately.Results and discussion The results showed that between genotypes as well as water stress treatment levels, there was no significant difference in number of heads per area. For head diameter in water stress conditions, in 27 genotypes head diameter was more than 11.4 cm and in 16 genotypes, head diameter did not reach even 10 cm. In non-stress conditions, Sil-96 genotype was shown the highest number of seeds per head by producing more than 842 seeds per head. However, 12 other genotypes were placed in a statistical group with this genotype. By applying water stress in 11 genotypes (including the Sil-96), the number of seeds per head was more than 630 and in 16 genotypes, the number of seeds per head was less than 400. In terms of weight of 1000 seeds, there was no significant difference between sunflower genotypes in both conditions of non-stress and water stress application. But by comparing two conditions of stress and non-stress, it was found that water stress caused a significant reduction in the weight of 1000 seeds in amount of 8.62%. Sil-96 genotype showed the highest seed yield in both stress and non-stress conditions. Although in each of the conditions of the water treatment, were placed into a statistical group with four other genotypes. Also, Sil-96 genotype had the highest stress tolerance index. Conclusions It seems that this genotype is recommended for cultivation in both conditions of stress and non-stress.
Mohammad-Reza Raeisi; Ehsan Shahbazi; Alireza Shafeinia
Abstract
IntroductionRapeseed (Brassica napus) as one of the most important oilseed crops is of great significance due to high amounts of unsaturated fatty acids and low amounts of saturated fatty acids. Among environmental stresses, drought stress is one of the most important factors limiting the growth and ...
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IntroductionRapeseed (Brassica napus) as one of the most important oilseed crops is of great significance due to high amounts of unsaturated fatty acids and low amounts of saturated fatty acids. Among environmental stresses, drought stress is one of the most important factors limiting the growth and yield of crops, which reduces the yield and yield components. However, the yield trait is controlled by several genes, other traits such as yield components can be used to improve drought stress tolerance. Introduction of drought resistant cultivars and stress management strategies are required considering the cultivation of rapeseed cultivars in many areas of Iran dealing with water shortages. Accordingly, several rapeseed doubled haploid lines were evaluated in two conditions of non-stress and water stress through this study. Materials and methodsA research was conducted at Ramin University of Agriculture and Natural Resources in Khuzestan under two water conditions (normal irrigation, post-flowering irrigation stop) in the form of augmented design with three control (Hyola 401, Hyola 420, and RGS003) in six replications during the period of 2014-2015 crop year in order to evaluate yield and yield components of 99 rapeseed doubled haploid lines. Under non-stress conditions, irrigation was performed when 50% of soil water was drained from field capacity, but for stress conditions, irrigation was performed when 70% of soil water was reduced from field capacity. To calculate the number of siliques per plant and the number of seeds per silique, 15 plants were selected from each line and the average were recorded for each treatment. Plants from each plot were dried in an oven at 70 °C for 72 h after drying outside. A seed counter device was then used to calculate 1000-seed weight. So that 1000 seeds were counted from each line and then weighed with a sensitive scale balance. Total seeds collected from each plot were weighed after separating seeds from straw to calculate the grain yield. Finally, yield was calculated per hectare using the proportion. Statistical analysis and computation of the results were performed using SAS and SPSS software. Mean comparison was conducted by using LSD method at 0.05 probability level. Results and discussionThe results of analysis of variance showed that there are significant differences between the genotypes for number of siliques per plant, number of seeds per silique and grain yield in both environments. The results of this study showed that there is a great variety of rapeseed doubled haploid lines in terms of yield and yield components, which can be used to improve the rapeseed yield. According to the results of stepwise regression in non-stress conditions, it is possible to use the number of siliques per plant as a criterion for selection and improvement of superior lines, but in conditions under stress, the 1000-seed weight should be considered as a criterion of selection. Lines 87, 7, 53, 23 and control Hyola 401 in non-stress conditions and lines 53 and 87, 84 had the highest yield in stress conditions. Based on sensitivity and tolerance indices, G53, G87, and G84 showed highest level of STI and lowest level of STI, therefore, these genotypes were found to be drought tolerant. ConclusionsLines 87, 7, 53, 84, and control Hyola 401 could be used in future plant breeding programs. As well as, lines 85 and 53 showed the least yield loss among lines with high yield under drought stress conditions and were introduced as adaptable lines with high yield under stress conditions.
Drought stress
Yousef Joshan; Behzad Sani; Hamid Jabbari; Hamid Mozafari; Payam Moaveni
Abstract
Introduction The importance of oil crops such as safflower has increased in recent years. Due to that safflower, can resistance in drought condition without reduction in yield, it can be a promising alternate crop in dryland agro-ecosystems. Plant have developed a wide variety of drought tolerance mechanisms ...
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Introduction The importance of oil crops such as safflower has increased in recent years. Due to that safflower, can resistance in drought condition without reduction in yield, it can be a promising alternate crop in dryland agro-ecosystems. Plant have developed a wide variety of drought tolerance mechanisms in morphological and physiological levels. There are wide variations among the safflower genotypes with respect to seed and oil yields at drought stress condition. Materials and methodsIn order to investigate the effects of late-season drought stress on some morphophysiological characteristics of Iranian safflower varieties, an experiment was conducted in the research field of Karaj Seed and Plant Improvement Research Institute. This study included two irrigation levels; normal irrigation (control) and drought stress from grain filling stage (main plot), and five Iranian safflower varieties including Sofeh, Goldasht, Golmehr, Padideh and Parnian (sub-plot), which conducted as a split-plot experiment in a randomized complete block design with three replications during the 2016-17. Results and discussion The results showed that drought stress had a significant effect on morphophysiological traits and seed yield of safflower varieties and decreased plant height, heads per plant, head diameter, seeds per head, 1000-seed weight and seed yield. Moreover, drought stress reduced relative water content, leaf area index and increased canopy temperature of safflower varieties. Late season drought stress reduced the growth duration of safflower varieties by 6-days compared with normal irrigation (control). Plant height of safflower varieties decreased under drought stress by an average of 8.2 cm. The highest plant height was observed in Parian variety (140.6 cm) in normal irrigation treatment. In contrast, under drought stress conditions, the highest plant height was observed in Golmehr (128.3 cm). In the present study, late season drought stress increased three degrees Celsius at safflower canopy temperature. The highest and lowest canopy temperatures were observed in Goldasht and Parian varieties (34.1 and 30.6 °C, respectively). Also, late season drought stress reduced leaf area index (LAI) by 34% in safflower varieties. The highest and lowest leaf area index were observed in Parnian and Goldasht varieties (2.4 and 0.7, respectively). Under non-stress conditions, the highest relative leaf water content (RWC) was observed in Parnian variety. In addition, in drought stress treatment, Parnian and Padide varieties had the highest RWC (67.4% and 66.1%, respectively). Drought stress reduced seed yield and seed oil content by 14.9 and 2.7%, respectively. Due to the number of heads and 1000-seed weight, Parnian variety had the highest seed yield at both control and drought stress conditions by 2150 and 1773 kg.ha-1, respectively. The highest seed yield loss due to drought stress was observed in Sofeh variety by 24.8%. Conclusion Overall results of this study showed that Parnian variety was significantly superior to other varieties in terms of morphophysiological characteristics such as LAI, RWC and seed yield under late season drought stress. According to this, in terms of morphophysiological traits affecting drought tolerance, this variety performed better than other varieties.
Niazali Ebrahimipak; Aslan Egdernezhad; Safoora Asadi Kapourchal; Davoud Khodadadi Dehkordi
Abstract
Introduction Climate conditions in Iran and high water consumption in agriculture have led to some solutions including deficit irrigation and the use of soil amendments such as superabsorbent polymers. However, application of such methods in long term is time consuming and expensive. For this reason, ...
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Introduction Climate conditions in Iran and high water consumption in agriculture have led to some solutions including deficit irrigation and the use of soil amendments such as superabsorbent polymers. However, application of such methods in long term is time consuming and expensive. For this reason, various plant models such as AquaCrop and SALTMED have been developed to overcome these problems. AquaCrop is the crop growth model developed by FAO and it is superior to other plant models because of its simplicity, the need for less data, user-friendliness and acceptable accuracy. AquaCrop simulates the yield response of crops to water and is particularly well suited to conditions in which water is a key limiting factor in crop production (Raes et al., 2012). The SALTMED model is a physically based model and can be used to simulate crop growth with an integrated approach considering water, crop, soil and field management. This model also is capable to simulate evapotranspiration processes, water flow and solute transport in soil and crop yield (Hirich et al., 2014; Ragab et al., 2010). A review of past studies has shown that so far few studies have been carried out using the SALTMED and AquaCrop models to simulate maize yield under irrigated and superabsorbent applications. Regarding this issue, the objective of this study was to evaluate SALTMED and AquaCrop models for simulating sweet maize yield under both deficit irrigation and superabsorbent applications. Materials and methodsThis research was carried out in the experimental farm in Ahwaz with Longitude of 48°32ʹ05ʺ and latitude of 31°15ʹ20ʺ and a height of 11m above sea level, in two spring and summer crop seasons in 2016. The experiments were carried out in a split plot design based on randomized complete block design with 12 treatments and three replicates. The designed treatments consisted of irrigation water quantity (at three levels of I1: 100%, I2: 75%, I3: 50% plant water requirement) and different levels of superabsorbent A300 (at four levels of S0: 0, S1: 0.3, S2: 0.6 and S3: 0.8 gr/kg of soil). In order to simulate the yield of Sweet maize, the spring crop dataset was used for calibration and the summer crop dataset was used for verification. Before the experiment, sampling of soil (at 0-30 and 30-60 cm depths) and irrigation water were performed and their physicochemical characteristics were measured. The seeds were then seeded in the amount of 78430 seeds per hectare. Up to four or five leaves stage, irrigation was performed based on 100% water requirement of the plant. From this stage, irrigation treatments were applied for each treatment. At the end of the growing season, to remove the marginal effect, plants were harvested in two square meters of the middle of each plot, and then grain yield and biomass of each treatment was measured. To evaluate the simulated yield of SALTMED and AquaCrop models with actual yield, the normalized root mean square error (NRMSE), root mean square error (RMSE), mean basin error (MBE), modeling efficiency (EF) and d-index (d) statistics were used. Results and discussionThe minimum difference between simulated values with SALTMED model and actual yield was obtained in I3S2 and I2S2 treatments with 3.5 and 3.9 percents, respectively. The maximum difference between these values was observed in I2S0 and I1S2 treatments with 16 and 15 percents, respectively. Nasrollahi et al. (2016) reported the maximum difference of 4.8% between simulated values by SALTMED model and actual values. The average of simulation error in this study was 9%, which is acceptable according to the results published by other researchers. Similar results for the AquaCrop model showed that the maximum and minimum differences between the simulated and measured values belongs to I2S2 and I1S0 treatments, respectively, with 23 and 1.3 percents, respectively. Results of NRMSE, RMSE, MBE, EF and D statistics for SALTMED model were 0.126, 0.587, 0.061, 0.92 and 0.91, respectively and for AquaCrop model were 0.155, 0.721 ton/ha, -0.090, 0.88 and 0.91 respectively. NRMSE for the AquaCrop model was equal to 0.155, which showed a higher value than the SALTMED model and this result is consistent with the results of Hassanli, Afrasiab and Ebrahimian (2015). The R2 statistic for the SALTMED and AquaCrop models was 0.93 and 0.91, respectively. These results further showed that the SALTMED and AquaCrop models were, respectively, overestimated and underestimated the real conditions. ConclusionsIn this study, SALTMED and AquaCrop models were evaluated for simulating Sweet maize yield under deficit irrigation and superabsorbent applications. The results showed that although SALTMED model performed a better accuracy than AquaCrop model, but the efficiency of both models was fairly acceptable in simulating sweet maize yield under the two applied experimental treatments.
Seyed Hamzeh Hosseinian; Mehri Saeedinia; Farhad Beiranvand
Abstract
IntroductionIn order to better management of plant performance under conditions of drought stress and study of the condition of plant growth, transpiration, plant stomatal conductance, plant photosynthesis (main determinant of plant growth), photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid), ...
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IntroductionIn order to better management of plant performance under conditions of drought stress and study of the condition of plant growth, transpiration, plant stomatal conductance, plant photosynthesis (main determinant of plant growth), photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid), a completely randomized block design with three replications was conducted in the Faculty of Agriculture of Lorestan University in 2017. The water stress treatments including 100, 80, 60 and 40 Percent of water requirement were applied. Irrigation was performed based on weighing method. Gas exchange measurements and morphological harvesting were done 80 and 90 days after stress. Results showed that water stress treatment has a significant reduction of stomatal conductance, transpiration rate, photosynthesis rate, intercellular CO2 concentration, photosynthetic water use efficiency and carboxylation efficiency. The highest values of the above parameters were related to control treatment and the lowest values were observed in treatment of 40% of water requirement. these values were decreased 68.08%, 59.99%, 61.42%, 37.96%, 20.79% and 37.5%, respectively, compared to the control treatment. As the result showed, the amount of stomatal conductance, transpiration rate, photosynthesis rate are affected by drought stress more than other parameters. Photosynthetic pigments were decreased significantly by increasing drought stress. The highest and lowest of chlorophyll a and b and carotenoid observed in control and heavy drought stress. Finally, drought stress significantly reduced the growth parameters such as plant height, stem diameter, dry weight of the plant. Material and methodsThe experiment was conducted in the research field of Faculty of Agriculture, Lorestan University, Khorramabad, Iran, through June to October 2017. The experimental site was located at 33029'N latitude, 48022'E longitude and 1125 m altitude above mean sea level. The experimental design was a randomized complete block with three replications. The seeds of summer Savory were sown in December with a density of 150 plants per square meter in plastic pots as micro lysimeters. Plastic pots with a diameter of 0.25 m and a height of 0.3 m were filled with a mixture, containing soil of the research field (near the greenhouse) and animal manure(4(soil):1(animal manure)). The soil texture was SCL. Weighing moisture at the field capacity point (θ_FC) and wilting point (θ_PWP) were obtained 32% and 16% using pressure plate. The treatments were 4 combinations of 4 irrigation water supply including: T1:100% of water requirement (control treatment), T2: 80% of water requirement, T3: 60% of water requirement, and T4: 40% of water requirement. Plants were harvested at flowering stage (95 days after planting). In control treatment, Irrigation was performed, when the soil moisture reached the low level of the readily available water (θ_m). These parameters were obtained from the following formulas (Allen et al., 1998).θ_m=|θ_fc-MAD(θ_fc-θ_PWP)|Where MAD is the maximum allowable depletion that was supposed to be 0.5; θ_FC is the percentage of moisture at the field capacity point; θ_PWP is the percentage of moisture at the wilting point. The water stress treatments were initiated 40 days after germination and continued until the end of the excrement (at flowering stage). After applying stress, considering water requirement in control treatment (T100), Irrigation requirement in T80, T60 and, T40 treatments were 0.8 (T100), 0.6(T100) and 0.4(T100). Photosynthetic parameters including photosynthesis rate, transpiration, stomatal conductance, Co2 sub stomatal were measured by Photosynthesis measurement device (Model LCA4) and chlorophyll content were measured by spectrophotometer based on Arnon's method. For statistical analysis, analysis of variance (ANOVA) and Dunkan’s test were performed using SAS software. Result and discussionResults showed that water stress treatment has a significant reduction on stomatal limiting factors such as stomatal conductance, transpiration rate, photosynthesis rate, inter cellular CO2 concentration, photosynthetic water use efficiency and carboxylation efficiency. Under this kind of condition, Satureja hortensis L. decreased stomatal factors in order to conserve water. Inter cellular CO2 concentration and finally photosynthetic rate decreased. The highest values of the above parameters were related to control treatment and the lowest values for 40% water requirement treatment, which were decreased 68.08%, 59.99%, 61.42%, 37.96%, 20.79% and 37.5%, respectively, compared to the control treatment. As the result showed, the amount of stomatal conductance, transpiration rate, photosynthesis rate are affected by drought stress more than other parameters. ConclusionResults of this research indicated that stomatal conductance, transpiration rate, photosynthesis rate, inter cellular CO2 concentration, photosynthetic water use efficiency and carboxylation efficiency were influenced by drought stress. These parameters decreased significantly as drought stress increased. The highest values of the above parameters observed in control treatment and the lowest values observed in 40% water requirement treatment.
Jahad Soorni; Javad Roustakhiz; Khaled Salimi; Mohsen Noori
Abstract
IntroductionCumin (Cuminum cyminum L.) as an annual herbaceous plant belonging to the Apiaceae family, is one of the most important medicinal plants in Iran, which needs a lower irrigation to complete the growth stages. Therefore, cumin is one of the most valuable plants for cultivation in arid and semi-arid ...
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IntroductionCumin (Cuminum cyminum L.) as an annual herbaceous plant belonging to the Apiaceae family, is one of the most important medicinal plants in Iran, which needs a lower irrigation to complete the growth stages. Therefore, cumin is one of the most valuable plants for cultivation in arid and semi-arid regions of the world, especially in drought conditions. Drought is one of the most important factors limiting the growth of plants around the world and the most common environmental stress. For this purpose, the present study was conducted to evaluate the key morphological and physiological parameters as well as the factors involved in oxidative stress and essential oil content in some ecotypes under drought stress and normal conditions. Materials and methodsThe experiment was arranged as factorial based on a completely randomized design with three replications and conducted in Saravan University's research greenhouse. Experimental factors included drought stress (stress and non-stress) and different ecotypes (eight ecotypes). The measured traits were plant height, number of secondary branches per plant, number of umbel per plant, number of umbellate per umbel, number of seeds per umbel, 1000-seed weight and seed yield per plant, chlorophyll a, b and carotenoid content, and activity of biochemical factors (catalase, superoxide dismutase, peroxidase, malondialdehyde) and also seed essence. Finally, analysis of variance and mean comparisons of the data were analyzed using SAS ver. 9.1 and R ver. 3.5.1 software. Results and discussionThe results showed that drought stress reduced yield, yield components and photosynthetic pigments content. In general, Birjand ecotype had the highest grain yield per plant (1.37 g). The activity of antioxidant enzymes in this medicinal plant was found to be valuable in which drought stress increased the activity of antioxidant enzymes and malondialdehyde levels. Birjand ecotype had the highest percentage of seed essence (3.25%) among the studied ecotypes, though had no significant difference with the Isfahan ecotype (3.8%). In non-stress conditions, the amount of biochemical factors was low. Under drought stress, the amount of these factors and essence content were significantly increased in the studied ecotypes. Ecotype Yazd in drought stress conditions produced catalase and superoxide dismutase content more than other ecotypes. Regarding the Birjand ecotype, which was one of the top ecotypes in this experiment, although the antioxidant activity of catalase and superoxide dismutase was not the highest, the level of malondialdehyde, which is a sign of damage to the plant, was also not high, and it is likely that the other mechanisms help to consistent the yield. Sabzevar ecotype had the highest (83.5%) and Birjand ecotype had the lowest (52.99%) increase in essential oil under drought stress condition. Finally, according to the measured indexes, the tolerance of the ecotypes studied to drought stress was identified and Birjand ecotype was identified as superior ecotype. ConclusionsIn this study, the effect of drought stress on flowering stage on functional, physiological, biochemical and essential aspects of native sub-cluster ecotypes was studied. The results showed that there was a good variation among different ecotypes for different traits and drought tolerance. In the meanwhile, Birjand ecotype had a certain superiority in terms of drought tolerance, grain yield and essential oil content than other ecotypes studied.
Safoora Kiani; Mani Mojaddam; Shahram Lak; Mojtaba Alavi Fazel; Alireza Shokuhfar
Abstract
IntroductionCorn scientific name (zea mays L) and annual monocot plants are poaceaae family. The corn is C4 and is native to the tropical region. The breadth of its degree of adaptation and adaptation makes it possible to cultivate it in temperate and cold regions. The corn is the third highest cereal ...
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IntroductionCorn scientific name (zea mays L) and annual monocot plants are poaceaae family. The corn is C4 and is native to the tropical region. The breadth of its degree of adaptation and adaptation makes it possible to cultivate it in temperate and cold regions. The corn is the third highest cereal after wheat and rice production, but its production is equal to the production volume of each of the world's two grains. The agricultural sector and its systems, with more than 90 percent of the country's water consumption, are the largest water consumer, wasting 80 percent of its traditional irrigation systems. Therefore, by reducing water resources, the reform of consumption patterns is the only way to overcome the depleted crisis. About 70% of the Earth's surface is covered by water, but unfortunately, the water crisis in many countries of the world, including the countries of the dry belt of the earth, such as Iran, is a concern. The use of natural fertilizers, including humic acid, with no harmful environmental effects can be effective in raising the yield and amount of plant biomass, especially in environmental conditions, henum humic acid is referred to as natural fertilizer of nature. Plant density, determined by number of plants per unit of land, is important in relation to the amount of crop production. Therefore, the purpose of this study was to investigate the effect of condensation and acidiferous application on quantitative yield and absorption of corn elements under drought stress conditions in Dehloran climate. Materials and methodsThis research was carried out in two years between 2015-2016 and 2016-2017 in a farm located in Dehloran with a longitude 47 degrees and 16 minutes east and a latitude 32 degrees and 41 minutes north and a height of 215 meters from the sea level. The experiment was carried out as split split plot in a randomized complete block design with three replications. The main factor was drought stress with three levels (optimal irrigation, irrigation cut off stage 6 to 8 leaf and irrigation cut off at crown stage). Subplots with three levels of foliar application of humic acid (control treatment (no humic acid), 2 and 4 liters per hectare humic acid) and sub-subplots including three plant densities (60, 75 and 90 thousand plants per hectare). ResultsThe results of combined analysis of variance showed that the effect of drought stress and humic acid on grain yield, 1000 seed weight, number of seeds per ear, zinc concentration, iron concentration and protein content were significant. In drought stress conditions, grain yield and nutrient uptake, such as iron, zinc and phosphorus, decreased but the protein content increased. The highest grain yield (9580 kg.ha-1) was related to irrigation. Humic acid spraying increased seed yield, zinc concentration and grain iron content. With increasing water deficit in soil, the effect of humic acid application on seed yield significantly decreased. Grain yield and protein percentage had a positive correlation with increasing plant density. ConclusionIn general, the results showed that irrigation, in addition to higher reliability and higher levels of yield, also makes it more efficient to use valuable inputs such as humic acid fertilizer. Under favorable moisture conditions, the increase of humic acid levels was associated with a significant increase in yield, and increasing the density to the average level (75 thousand plants) had a very positive effect on grain yield. In drought stress conditions at crownflower stage, decrease in adsorption and increase of moisture content of humic acid due to water deficit in soil reduced the positive effect of increasing of humic acid on increasing grain yield. Under these conditions, the use of high density did not only increase yield but also reduced all l traits. Therefore, the approach of organic and natural fertilizers such as the humic acid foliar application, in addition to increasing yield, it can play a positive role in reducing the use of chemical fertilizers and environmental pollution, so as a natural source material, it can be used to sustain and increase crop production. Regarding the lack of observation of the negative effects of humic acid on plants and increasing quantitative yield and absorb the elements, it seems better if the plant's encounter with limited irrigation conditions during the growth period is possible, humic acid could be applied on this plant in order to increase the yield of corn.
Saleh Jahanbkhsh; Gholamreza Khajoei-Nejad; Rohollah Moradi; Mahdi Naghizadeh
Abstract
Introduction Quinoa (Chenopodium quinoa willd.) is an annual herbaceous plant belongs to Amaranthaceae family, but formerly placed in Chenopodiaceae family that originated in the Pacific slopes of the Andes in South America. It is cultivated in the world with an area of 126 thousand hectares with a production ...
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Introduction Quinoa (Chenopodium quinoa willd.) is an annual herbaceous plant belongs to Amaranthaceae family, but formerly placed in Chenopodiaceae family that originated in the Pacific slopes of the Andes in South America. It is cultivated in the world with an area of 126 thousand hectares with a production of 103 thousand tonnes. Determining the most suitable planting date means determining when plant growth and development are most consistent with climatic factors and the plant is less exposed to unfavorable environmental conditions. The management of planting date has the greatest impact on the phenological and growth characteristics of the plants compared to other treatments. Hirich et al. (2014) reported that 1st December (7.89 t ha-1) and 15th November (7.01 t ha-1) were found to record significantly higher dry matter production of quinoa than 15th March date of sowing among ten dates of sowing at an interval of 15 days from 1st November to 15th March. Reducing water resources for agricultural production is one of the main concerns of planners in most countries, especially in dry and semi-arid regions. Quinoa has been introduced as a drought tolerant and salinity resistant plant. One of the most important drought-tolerant mechanisms of the plant is the flexibility of the phenology and plant growth cycle when exposed to drought stress. Salicylic acid (SA) is a phenolic compound involved in the regulation of growth and development of plants, and their responses to biotic and abiotic stress factors. The objectives of this research were to determine the most suitable planting date of Quinoa in Bardsir, determine the optimal irrigation requirement, and investigate the role of salicylic acid in Quinoa resistance to drought stress. Materials and methods This study was conducted as split-split-plot based on randomized complete block design with three replications at experiment station of the Agricultural Faculty of Bardsir, Shahid Bahonar University of Kerman at 2018. The experimental treatments were planting date (5 April, 5 May and 5 June) assigned to main plot, irrigation levels (90%, 60% and 30% of filed capacity) as subplot and foliar application (salicylic acid 1 mM and water) as sub-subplot. Data were subjected to two-way analysis of variance (ANOVA) and the difference between treatment means was separated using LSD test. A significance level of 95% was applied by SAS 9.2. Results and discussionThe results showed that the delay in planting date shortened the Quinoa growth period. GDD and growth period were decreased by drought stress. May planting date has significantly higher root length (31.81 cm) and dry weight (9.09 g plant-1) than two other planting dates. The highest root length for April (28.27 cm) and May (35.92) planting dates was assigned at 60% of FC, while for June (21.27 cm) was related to no-stress condition. Averagely, seed yield for May (653.91 kg ha-1) planting date was significantly higher than April (578.7 kg ha-1) and June (460.8 kg ha-1). Decrease in consumed water to 60% of FC had no significant effect on seed yield, but the trait value in 30% of FC was significantly lower than other irrigation levels. Justly at severe drought level, seed yield was significantly increased by foliar application of salicylic acid than water application. Relationship of seed yield was positive with seed oil percentage (r = 0.82) and was negative with protein percentage (r = -0.78). Water use efficiency (WUE) was significantly higher in May planting date than in April and June planting date. WUE increased significantly with water consumption decreasing. Conclusion Generally, the results illustrated that May planting date is the most suitable planting date for Quinoa in Bardsir regions and same climates. Results showed that the plant has a considerable tolerate in water stress condition. Salicylic acid could mitigate the negative impacts of drought stress in limited irrigation levels.
Hossein Azadvari; Naeemi Masoumeh; Abdollatif Gholizadeh; Ali Nakhzari Moghaddam
Abstract
Introduction Drought stress has different effects on morphological, physiological and biochemical processes of plants. Growth regulators play a crucial role during plant growth and development and utilizing of them can a possible approach to improving plants economic grain yield. Salicylic acid plays ...
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Introduction Drought stress has different effects on morphological, physiological and biochemical processes of plants. Growth regulators play a crucial role during plant growth and development and utilizing of them can a possible approach to improving plants economic grain yield. Salicylic acid plays an essential role in regulating various physiological processes such as growth, plant development, ion absorption, photosynthesis and germination. The aim of this study was to determine the most suitable method for the application of salicylic acid as a drought tolerant inducer and to investigate the effect of salicylic acid on physiological traits and herb yield of black cumin under different irrigation regimes. Materials and Methods This study was conducted based on randomized complete design with factorial arrangement of treatment and three replications at Gonbad Kavous university research field in 2018 growing season. Different irrigation regimes at four levels including no irrigation (dry farm), once irrigation at flowering stage, once irrigation at grain filling stage and double irrigation at flowering and grain filling stages and salicylic acid factor at three levels including non- application (control), seed priming (0.5 mM -1), foliar spraying (0.5 mM -1) were studied. In this study, some traits such as amount of chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, electrolyte leakage, proline, soluble sugars and grain yield were evaluated. Statistical calculations were performed using SAS software version 9.1 and the obtained measurements were compared using LSD test and probability level five. Results and discussion The results showed that the effects of simple irrigation and salicylic acid and their interactions on all studied traits were significant.Salicylic acid spraying increased the content of proline and soluble sugars in all irrigation conditions. The lowest amount of membrane degradation was observed from salicylic acid priming treatment (39.67%) under irrigated conditions and the highest amount of membrane degradation was observed in salicylic acid (72.33%) absence in dry farm conditions. Salicylic acid spraying led to an increase in photosynthetic pigmentation at all levels of irrigation. Also, the highest grain yield was obtained from spray application (1329.66 kg/ ha-1) under irrigated conditions and the least grain yield belonged to non-salicylic acid treatment (817.33 kg/ ha-1) under dry farm conditions. It seems that spillage of silicic acid has been shown to be a retrograde process and, by increasing the antioxidant capacity of the cell, decreases the amount of peroxidation of the lipids and further protects cell membranes and photosynthesis and photosynthetic pigments and prevents chlorophyll catabolism. Reducing membrane damage due to the use of salicylic acid, known as the main way to increase drought resistance in the plant, may be associated with the production of antioxidants that the production of antioxidants is a response from the plant to reduce the oxidation damage. In other words, salicylic acid increases the membrane stability against oxidative stresses. Salicylic acid leads to proline accumulation in the plant by induction of protective interactions with aqueous humor hormones. According to the results, it is observed that the soluble sugars in sprayed plants were more than primed seeds and did not consume salicylic acid. In addition, drought stress increased the amount of soluble sugars, but the increase caused by spraying was higher than that in stress Is significantly higher. It seems that salicylic acid increases the amount of sugars in plants by increasing the amount of photosynthetic pigments, reducing oxidative stress and protecting chloroplast and cell membranes. Application of salicylic acid improved seed yield through positive effects on photosynthesis, photosynthetic material transfer, inoculation of flowers, preventing severe abortion of flowers and increasing grain filling time. The results also showed that salicylic acid could have a positive effect on grain yield in dry farm condition, so that the application of salicylic acid as spraying and priming increased the yield of 23.08 and 14.39 percent, respectively, than salicylic acid. Conclusions According to the results of this study, it can be concluded that the application of salicylic acid as foliar spraying is a suitable strategy for increasing the resistance of black cumin to drought stress.
Fereshteh Darabi; Nosratollah Abbasi; Mohammad Javad Zarea
Abstract
Introduction Polyamines include spermidine, spermine and putrescine, are the polyacetyl compounds with low molecular weight, which play a role as osmotic regulators. They also contribute to the regulation of some of the essential cellular processes such as DNA replication, transcription, translocation, ...
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Introduction Polyamines include spermidine, spermine and putrescine, are the polyacetyl compounds with low molecular weight, which play a role as osmotic regulators. They also contribute to the regulation of some of the essential cellular processes such as DNA replication, transcription, translocation, cell division, regulation of enzymes activity, maintaining membrane stability, sweeping active radicals, and tolerance to various stresses. Brassinosteroids have increased the tolerance in a wide range of environmental stresses such as drought, salinity, cold and heat. This increase is generally dependent on production and increase of transcription of genes responsible for stress response and in order to increase the tolerance of plants treated with brassinosteroids. In this regard, a trial was conducted to clarify the role of growth regulators (putrescine and brassinosteroid) on controlling oxidative stress and physiological changes during tolerance to water deficit in basil plant. Materials and methodsThis experiment was conducted as split plot factorial in a randomized complete block design with three replications at Research Farm, Faculty of Agriculture, Ilam University. Experimental treatments consisted of drought stress at three levels (I1: 40, I2: 80 and I3: 120 mm evaporation from the evaporation pan) as the main factor, putrescine spray at three levels (Put0:0, Put1: 0.5 and Put2: 2 milli molar) and brassinosteroid spray in three levels (Br0: 0, Br1: 0.5 and Br2: 2MM) as sub plots. Seeds of the Afghani cultivar were planted on May 20th. To prevent the lateral movement of the water, stacks 1 meter width were placed around each plot. To ensure greater on the lateral water movement, the spacing between the plots for different irrigation treatments was considered as 2 m. No herbicide was used to control weeds in this experiment. Instead, weeding was done to control them. Due to the absence of pests and diseases in experimental plots, pesticides were not used. In this research, changes in the content of photosynthetic pigments of leaves, flavonoids, leaf relative water content, photosynthesis rate, co2 concentration, proline and ion leakage were investigated on basil. Variance analysis of data was performed using SAS 9.1 software and comparison of meanings was made with a minimum difference of 5% probability level and drawing the shapes was carried out in Excel software environment. Results and discussionAccording to the results of analysis of variance, the traits of leaf relative water content, ion leakage, flavonoids, photosynthetic pigments, photosynthesis velocity, sub-stomatal CO2 concentration and basal significantly affected by the triple interaction (Wetting treatment × putrescine × brassinosteroid). According to the results of this study, the amount of chlorophyll a and b, flavonoids and the concentration of Co2 under the stomata in Br2× Put2 treatment under non-stress conditions (I1) were increased as 74.77, 64, 68/45 and 19.5%, in medium stress (I2) were increased as 61.4, 33.9, 6.3 and 10.3%, and in severe drought stress (I3) were increased as 62.1, 68.6, 33.1 and 15.7, compared to control treatment (Br0 Put0 ×), respectively. The rates of photosynthesis was reduced under drought stress. However, under Put2 × Br1 in moderate (I2) and severe (I3) drought stress (I3), they were increased as 76.59% and 83.33% as well as 10% and 16% in compare with Br0 Put0 treatment, respectively. Put2 × Br1 treatment reduced the level of ion leakage under all drought stress levels. ConclusionsSince polyamines are considered as effective molecules in the signaling pathway for drought stress, the spraying of these substances will lead to the induction of plant defense responses. Most likely, these responses led to increased tolerance of basil plant to drought stress and increased photosynthetic pigments as well as physiological characteristics. In general, it seems that high consumption of putrescine and brassinosteroid (Put2 and Br2) in drought stress can improve the physiological parameters in basil plant.
Norollah Kheyri; Maryam Abbasalipour
Abstract
Introduction Rice is the main food for more than half of the world population (Reis et al., 2018), which is one of the most sensitive plants to water stress (Yang et al., 2008). Among the various environmental stresses, drought stress is one of the most damaging due to a significant reduction in crop ...
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Introduction Rice is the main food for more than half of the world population (Reis et al., 2018), which is one of the most sensitive plants to water stress (Yang et al., 2008). Among the various environmental stresses, drought stress is one of the most damaging due to a significant reduction in crop yield, which can reach billions of dollars annually worldwide (Tardieu et al., 2014). Water stress in different growth stages of plant decreases the growth and grain and straw yields of rice (Venkatesan et al., 2005). Water deficit stress after flowering stage has little effect on yield and yield components of rice (Wu et al., 2011).Zinc as a cofactor of antioxidant enzymes such as peroxidase and superoxide dismutase plays an important role in plant resistance to drought stress (Welch, 2001). Application of nutrients in the form of nanoparticles improves resistance of plants to biotic and abiotic stresses and increases the nutrient utilization efficiency (Alharby et al., 2016). Foliar application of nano-ZnO can be effective in improving the performance of total biomass and leaf area index under water stress (Kheirizadeh Arough et al., 2015). Therefore, the purpose of this study was to investigate the effects of doses of nano-ZnO in different stages of water stress on yield components, yield, Zn concentration and uptake in plant tissue, as well as Zn efficiency indices in rice (cv. Tarom Hashemi).Materials and methods The experiment was conducted as split plot in a randomized complete block design with three replications in Amol in 2016. Irrigation in four levels (I1: control or flood irrigation, I2: water stress at tillering stage for 15 days, I3: water stress at flowering stage for 15 days, and I4: water stress at grain filling stage for 15 days) were considered as main plots and foliar application of ZnO nanoparticles in four levels (Zn1: 0, Zn2: 25, Zn3: 50 and Zn4: 75 mg ZnO l-1) as sub-plots. Zn foliar application was performed at four stages of plant growth including early tillering, mid-tillering, booting stage and full heading stage. At the end of the season, some agronomic and physiological traits, as well as Zn efficiency indices in rice were determined. Data analysis was done by using MSTAT-C software and means were compared using the LSD test at the probability level of 5%. Results and discussion The results showed that the effect of irrigation levels was significant on all the yield components, yield and Zn concentration and uptake in grain and straw of rice. The effect of different doses of Nano-ZnO was significant on all the measured traits except for the 1000-grain weight. Also, the interaction effect of the experimental factors was not found to be significant on the studied traits. The yield, yield components, as well as the Zn concentration and uptake in grain and straw of rice were significantly reduced under water stress, especially at flowering stage. So, when irrigation was stopped at flowering stage, the grain yield decreased by 30.2% compared with flood irrigation condition, while the yield did not significantly decreased by water stress at grain filling stage. Water stress at flowering stage due to reduced the panicle length and number of filled grains per panicle led to a significant decrease in grain yield compared with flood irrigation conditions. The use of 50 and 75 mg.l-1 Nano-ZnO resulted in improved the panicle length, number of fertile tillers per hill, number of filled grains per panicle, Zn concentration and uptake in plant tissue, and finally the grain yield compared with control. There was a significant positive correlation between Nano-ZnO and grain yield at a probability level of 1%. The increase of grain yield by nano-ZnO foliar application have been reported in other crops such as wheat (Karimi, 2014), triticale (Kheirizadeh Arough et al., 2015), mungbean (Shojaei and Makarian, 2014) and foxtail millet (Davoodi et al., 2013). By increasing the application of ZnO nanoparticles at higher doses, especially in rate of 75 mg.l-1, decreased the Zn efficiency indices in rice.Conclusions The highest grain yield was obtained under flood irrigation, but water stress at flowering stage caused a significant decrease in yield and Zn uptake of rice plant tissue, which indicates the plant's high sensitivity to water deficit in this growth stage. Although by application of different doses of Nano-ZnO improved the yield components, yield and Zn uptake in grain and straw of rice compared with control, but application of 50 and 75 mg.l-1 Nano-ZnO produced the maximum yield and Zn uptake in plant tissue. Therefore, the flood irrigation during the plant growth period with application of 50 mg.l-1 ZnO nanoparticles is appropriate for improving the yield and Zn uptake in rice grains.
Hossein Hammami; Farhad Azarmiatajan; Mostafa Yaghoobzadeh
Abstract
Introduction As a major constraint limiting crop production worldwide, water deficit during plant growth period results inhibition effects on growth and yield of crops. Under drought stress, growth of crops inhibited by decline in water uptake, disturb photosynthetic path, growth retardation, metabolic ...
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Introduction As a major constraint limiting crop production worldwide, water deficit during plant growth period results inhibition effects on growth and yield of crops. Under drought stress, growth of crops inhibited by decline in water uptake, disturb photosynthetic path, growth retardation, metabolic disturbances oxidative damage and. Therefore, it is urgent to alleviate the adverse effects of drought stress for achieving high crop yields. Among various strategies to alleviate deleterious effects of drought stress, seed priming is thought to be an easily applied, low-cost and effective approach (Ashraf and Foolad, 2005). Seed priming include Hydropriming by water, osmopriming by ascorbic acid, potassium salts, poly ethylene glycol improved the drought resistance of different crops such as wheat (Farooq et al., 2013), lentil (Saglam et al., 2010), sunflower (Kaya et al., 2006), barley (Tabatabaei, 2013), and rice (Sun et al., 2010). Since, this study was conducted for determination growth and yield response of wheat to seed priming and different irrigation levels. Materials and mthods In order to evaluate the response of wheat to seed priming and irrigation levels, a factorial experiment based on a completely randomized block design with three replications was conducted at Research field of agriculture, University of Birjand, in 2017-2018. The treatments consisted of three levels of irrigation (I1, I2 and I3, 100, 75 and 50% of the plant water requirement, respectively) and four levels of seed priming (P1, P2, P3 and P4, 0 (control), -0.3, -0.6 and -0.9 MPa induced by PEG 6000, respectively). At the end of season growth period, plant height, tiller number, spike number, spike length, grain number per spike, 1000 seed weight, biological yield, and grain yield were measured and harvest index calculated. The traits were measured from 1 m2 of the center of each plot. Plant height, tiller number, spike number, spike length, and grain number per spike were average of ten plants. Results and discussion The results of this experiment showed that irrigation levels had a significant effect on measured traits including plant height, tiller number, spike number, spike length, grain number per spike, 1000 seed weight, biological yield, grain yield (P <0.01). However, no significant effect was observed on harvest index. Seed priming had significant effect on plant height and spike length (P <0.01), number of tillers, number of seeds per spike, biological yield, grain yield (P <0.05). Interaction effects showed a significant effect on all of the traits except harvest index. The results of this study showed that the application of osmotic priming seeds -0.3, -0.6, -0.9 MPa resulted in 2.13, 2.62 and 2.15 times of seed yield at 50% water requirement treatment compared to without seed priming treatment. The results of means comparison showed that osmotic seed priming by polyethylene glycol, resulting in a pressure of -0.6 MPa, under 50% of the water requirement treatment showed the highest grain yield compensate ability. However, in 75% of water requirement treatment, pre-treatment had no significant and positive effect on grain yield, even in -0.9 MPa treatment, had a negative and significant effect on seed yield. Therefore, the application of osmotic seed priming somewhat compensated the damage caused by water shortage on grain yield under stress conditions of 50% of water requirement. While in non-stress conditions, osmotic seed priming had no positive effect on grain yield.
Omid Reza Saali; Ehsan Zeidali; Mohammad Reza Ardakani; Zahra Tahmasebi; Hamid Reza Dorri; Mehrshad Barary
Abstract
Introduction Among the inhibitory factors affecting the growth and yield of crops, drought is the most important factor in reducing production, especially in arid and semi-arid regions. Since agriculture in Iran, with more than 90% of water resources being used as the main water user in agriculture, ...
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Introduction Among the inhibitory factors affecting the growth and yield of crops, drought is the most important factor in reducing production, especially in arid and semi-arid regions. Since agriculture in Iran, with more than 90% of water resources being used as the main water user in agriculture, any saving in this sector will be an effective contribution to the conservation of water resources. Biocahr is used in cases such as drought stress, salinity, weeds, soil degradation by various factors, carbon sequestration, coping with the spread of greenhouse gases. In order to study evaluation the effects of biochar and mycorrhizal symbiosis application on reduction water stress in corn a field experiment.Materials and methodsIn order to investigate the effect of drought stress on the row number per ear, seed number per row, seed number per ear , 1000-seed weight, seed yield, chlorophyll a and b and harvest index of corn, a split split plot arranged in complete randomized blocks design with three replications in Agricultural Research Center of Markazi Province in 2014-2015 crop season. main plots consisted of two level of irrigation, water stress and irrigation (control, sub mplots consisted of four level of biochar, non-application of biochar (control), application of 7 ton biochar per hectare, 14 ton biochar per hectare, 21 ton biochar per hectare and sub-sub-plot consist of two level of mycorrhiza fungus,(non application of mycorrhiza fungus (control), application of mycorrhiza fungus. In the case of the main factor where two levels of irrigation and limited irrigation (stress), according to available facilities, using a class A evaporation pan (for irrigation after 60 mm evaporation and for stress; irrigation after 110 mm evaporation) Was considered. It should be noted that the time of application of water stress from the 8-leaf stage of corn was considered.Results and discussionResults showed that stress treatment seed number per row, 1000-seed weight and chlorophyll a had significant effect on this traits and in addition stress reduced the traits evaluated. Biochar application of 1000 seed weight and content of chlorophyll a and b did not have a significant effect, but had significant effect on other traits and at application of biochar (14 ton/ha), the yield increased 1.31 ton/ha compared to control. Mycorrhiza fungus treatment had significant effect on seed number per row, 1000-seed weight, seed yield and harvest index And increased by 8.3, 9.3, 7 and 11.8% respectively. In stress condition and application of biochar (7 tons per hectare), an increase of 10.8 percent of the weight of the 1000-thousandth weight was observed compared to the control. Interaction effects of stress and biochar had significant effects on the seed number per ear and 1000-seed weight. So intraction effects of stress and fungus had a significant effects on seed number per row, seed number per ear, seed yield and harvest index and the interaction effects of biochar and fungus had not significant effect on the traits evaluated. Finally the triple interaction effects had significant effects on seed number per ear, 1000-seed weight and seed yield. In stress condition, the highest grain yield was obtained with an average of 13.87 t / ha with biochar application of 14 t / ha.ConclusionsThe overall results of the experiment showed that under stress conditions, biochar had a significant effect on the final yield of corn grain, so that the grain yield was obtained with a mean of 13.87 ton/ha and in the absence of using the fungus and application level of 14 ton/ha (third level) which indicates a 12% increase in grain yield under stress conditions, compared to non-application of biohazard in stress conditions. Regarding the remaining traits, it was also observed that under stress conditions and using of biochar levels, especially at the level of 14 ton/ha, it had the highest efficiency due to the climate, ecological conditions of the study area and increased the traits.
Seyed Hamid Reza Hashemi-Petroudi; Hamid Reza Ghorbani
Abstract
IntroductionAbiotic stress has always affected the plants growth and development through morphological and physiological, biochemical and anatomical alterations, leading to reduce yield and limit the crop area. Development is a completed process that depends on a cell to cell communication to regulate ...
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IntroductionAbiotic stress has always affected the plants growth and development through morphological and physiological, biochemical and anatomical alterations, leading to reduce yield and limit the crop area. Development is a completed process that depends on a cell to cell communication to regulate growth and differentiation. In the past, phytohormones were considered the important players of cell signaling. High-throughput techniques have led to finding many new plant peptides over the last years. DEVILS are small peptides that play an important role in plant growth and development and are effective in controlling plant responses to environmental changes caused by stress. These small peptides act in the growth process of plants similar to phytohormones and are called peptide hormones that play a role in plants as molecular messengers. Aeluropus littoralis, belongs to Poaceae that can tolerate NaCl up to 600 mM and grows in marshes, salty and drought lands. Because of C4 photosynthesis system and proper physiological properties, A. littoralis as a halophyte plant could be known as a great source of genes related to salt tolerance. Materials and methods In this research, the changes of expression of four genes namaly AlDVL1, AlDVL2, AlDVL3, and AlDVL6 were investigated under salinity stress (600 mM) in Aeluropus littoralis as a halophyte plant at five time-points of 0, 3, 6, 48 and 168 hours post stress (hps). Leaves and roots were sampled and grounded in liquid nitrogen, and total RNA was extracted using Threezol reagent (Riragene). First strand cDNA synthesis and RT-qPCR were performed according to kit instructions. PCR amplification was performed in C1000™ Thermal Cycler (Bio-Rad, USA) according to the company’s suggestions. The 2-ΔΔct method was applied for the relative expression analysis. Results and discussionThe results showed that the expression pattern of AlDVL genes was affected by salinity stress and had a significant change in root and leaf tissues. In all of genes except AlDVL6, expression changes in the leaf were higher than the root. The highest value of expression in the leaf and root tissue was observed at 48 hps (12.12) and 168 hps (14.83) for AlDVL2, respectively. Expression pattern of AlDVL genes was tissue-specific, and different pattern was observed in root and leaf tissues, while in each tissue, all genes had similar pattern. For example, in all of the studied genes in leaf tissue, the amount of expression of genes was first reduced in the initial time-point, and then the expression increased to 48 hours after the stress and eventually decreased over 168 hps. This trend of change was observed among different genes with a slight difference in leaf tissue. In the root tissue, the trend of gene expression was similar except for the AlDVL3 gene. From the first hours to 48 hps, gene expression value was declined, but was peaked at 168 hps. According to the results, it can be stated that the genes act specifically in each tissue. The results of correlation analysis in different tissues showed that AlDVL6 and AlDVL3 expression correlation in both leaf and root tissues had a negative and significant relation (-0.6) with inverse effects. ConclusionsHalophyte plants by regulating their gene expression can respond to different various abiotic stresses. Expression pattern of phytohormones -related genes in leaf and root tissue can be taken as an indication of their functional relevance at different time-points of salt stress.
Elham Younesi-Melerdi; Ghorbanali Nematzadeh; Ali Pakdin-Parizi
Abstract
Introduction Salt stress is one of the most important environmental stresses which severely affect agricultural economy in the world. Improving the salt-tolerance ability of crops and comprehending the complex mechanisms behind the salinity tolerance are two main fields of study in agricultural sciences. ...
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Introduction Salt stress is one of the most important environmental stresses which severely affect agricultural economy in the world. Improving the salt-tolerance ability of crops and comprehending the complex mechanisms behind the salinity tolerance are two main fields of study in agricultural sciences. Plants respond to the destructive effects of salinity through changes in physiological and molecular processes. Materials and methods In the present study the activity of SOD and APX antioxidant enzymes were measured. In addition to, changes in the expression of G-types-LecRLK, CIPK20, HSFA1a and C3H-ZF genes, involved in signaling and regulatory networks of Aeluropus littoralis, under salt stress has been investigated. The plant cuttings were cultured hydroponically under controlled conditions. The experimental design was consisted of a control (Hoagland’s solution with no NaCl added) and two treatments (200 and 400 mM NaCl). After 72 h of salt treatment, leaf samples were harvested and H2O2 content, SOD and APX enzymes activity were investigated. Then, total RNA was extracted using RNeasy Plant Mini Kit from leaf samples of control and treated plants. The integrity and quantity of RNA was determined by agarose gel electrophoresis and spectrophotometry, respectively. RNA was treated with RNase free DNase I and1 µg of total RNA used as template for first strand cDNA synthesis by Revert Aid Reverse Transcriptase kit according to manufacturer’s protocol. Three individual plants were taken for each treatment under each biological replicate and the final results represents the data obtained from three biological replicates. Data were statistically analyzed for the ANOVA and the significance of the differences between mean values of control and salinity-treated plants was determined using Tukey test. For qRT-PCR analysis, three independent RNA samples were used for each sample, and each reaction was run in triplicate for both control and salt-treated samples. Results and discussion The results showed that the activity of antioxidant enzymes in both concentration 200 and 400 mM was significantly increased (p < 0.05). The lecRLK gene expression was not significantly changed among different treatments. The expression of CIPK20 gene were decreased 7 and 16 folds lower than control at 200 and 400 Mm of NaCl treatments, respectively. The obtained results revealed that expression of HSFA1a gene was positively associated with salt concentration (p < 0.05). So that, 11 and 13 fold HSFA1a gene expression more than control was observed. The expression of ZF30 gene was decreased significantly in both 200 and 400 mM NaCl treatments (p < 0.05). The results showed that the expression pattern of studied genes is different under salt stress conditions that can be related to the role of each gene, salt concentration and duration of stress. Conclusion Generally, a large number of genes in plants are induced after exposure to various abiotic stresses and function in different ways to confer stress tolerance to plants. Expression of genes involved in the transduction of salt stress signals is induced during early phases of stress response. Our study revealed not only the similar data to other published studies, but also some new information, such as the role of salt stress intensity and exposure time on signaling and regulatory mechanisms of response to salt stress. These results will benefit our understanding of the molecular mechanisms underlying resistance to salinity in A. littoralis.
Fahimeh Hosseinirad; Eisa Jorjani; Hossein Sabouri; Ebrahim Gholamalipor Alamdari
Abstract
Introduction Rice (Oryza sativa L.) is one of the most important crops in the world, especially in Asian countries that provides energy for more than 2.7 billion people worldwide daily, and is planted on approximately one-tenth of the earth's arable land. Rice is one of the most important cereal and ...
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Introduction Rice (Oryza sativa L.) is one of the most important crops in the world, especially in Asian countries that provides energy for more than 2.7 billion people worldwide daily, and is planted on approximately one-tenth of the earth's arable land. Rice is one of the most important cereal and salinity is a major limitation in the development of rice cultivation. Genetically improving salt tolerance of rice is a highly important objective of rice breeding programs. Traits such as salt tolerance are quantitatively inherited. Therefore, mapping quantitative trait loci (QTL) with molecular markers can be very helpful to plant breeders in the field of agricultural genomics. Therefore, the present study was conducted to mapping of genotype code, starch, phenol, proline and chlorophyll content. Materials and methods A F8 RILs population, derived from a cross between a salt tolerance Ahlemi Tarom (ATM) and salt sensitive Neda (NAD) which were used in this study. The genetic material involved 96 lines were used to evaluate the salt tolerance. This experiment was conducted at the Gonbad Kavous University at 2014 under hydroponics condition. The seeds were placed 50 ˚C for 3 days to break dormancy, and then germinated at 25 ˚C for four days. Finally, the germinated seeds were sown in holes of the Styrofoam board with a nylon net bottom and roots were placed in water. which floated on water for 3 days, and after were transferred to float on Yoshida's nutrient solution for 11 days. Two weeks after sowing, the seedlings were transferred to nutrient solution with electrical conductivity 6 dSm-1 for 7 days, then NaCl concentration was increased to 12 dSm-1 for further 7 days. This experiment was conducted in a controlled condition with 16-hours photoperiod, temperature of 29/21 ˚C, and minimum relative humidity of 70%. The culture solution was renewed weekly and pH solution was controlled three times a and was fixed constant by adding either NaOH or HCL. Chlorophyll content was measured using a SPAD device. The polymerase chain reaction was performed in a volume of 10 µL for each reaction. Polymerase chain reaction products were then separated using a 6% polyacrylamide gel and stained with fast nitrate of silver. The 96 lines Genetic linkage maps was prepared using 30 SSR markers and 15 ISSR markers covering 1411.3 cM of the rice genome. The average distance between two adjacent markers was 15.34 cM. Results and discussion For genotyping code, a QTL was detected on chromosome 7, explained 9.3% of phenotypic variation in the trait. For starch content, a gene locus was identified on chromosome 4, which had a LOD of 2.799. The additive effect for this QTL was 6.756 and explained 12.6% of the phenotypic variation in the trait. For the phenol content, a gene location was detected on chromosome 7, which explained 15.2% of the phenotypic variance of the trait, and had LOD and additive effect of 2.728 and 3.4338, respectively. The allels of the parents of Ahlemi Tarom increased this trait. For a chlorophyll content, a QTL was detected on chromosome 5, with an LOD of 2.2. This QTL had an additive effect and a R2 of 0.097 and 9.2, respectively. Conclusion A total of four genetic locations were identified for four traits genotype code, starch, phenol, proline and chlorophyll content, respectively, on chromosomes 7, 4, 7 and 5, and explained 9.3, 12.6, 15.2 and 9.2 % of phenotypic variation of the traits. These locus had a LOD were 2.038, 2.799, 3.438 and 2.02, respectively. No QTL was detected for proline. The results of this study can identify the better genotypes in term of traits checked for marker selection programs.
Somayyeh Sanchouli; Mahmoud Ghorbanzadeh Neghab; Hossein Sabouri; Mohammad , Zare Mehrjerdi
Abstract
Introduction Rice (Oryza sativa L.) is one of the most important crops in the world, providing food to more than 3 billion people in the world, and is grown in about one-third of the world's agricultural land. Osmotic stress (such as drought stress) is a serious limiting factor to rice production and ...
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Introduction Rice (Oryza sativa L.) is one of the most important crops in the world, providing food to more than 3 billion people in the world, and is grown in about one-third of the world's agricultural land. Osmotic stress (such as drought stress) is a serious limiting factor to rice production and yield stability, worldwide. Therefore, this study was conducted to locate QTLs associated with germination stress and determine the contribution of each QTL to phenotypic variation of traits. Materials and method The plant material used in the present study was 74 lines from the F8 recombinant inbred lines of Neda × Ahlami Tarom cultivars that investigated at University of Gonbad Kavous in 2017. Factorial experiment was conducted in a completely randomized design with 9 cm diameter petri dishes with 2 replications. 100 healthy seeds were selected from 74 populations of F8, which were the result of the collision between Ahlami Tarom and Neda. The seeds were washed with 2% sodium hypochlorite solution for 10 minutes and then washed with distilled water three times. The seeds were applied to sterilized sterile filter paper and mannitol, NaCl and polyethylene glycol treatments were applied. Petri dishes were placed inside the germinator at 25 ° C and 70% moisture and darkness for one week. The number of germinated seeds for each of the lines was counted in 24, 48, 72, 96, 120, 144, 168 hours after being placed in Petri Dish, and 14 days after the culturing, the root length, The length of the stalk and the length of the coleoptile were measured using caliper and millimeters. The linkage map was based on 40 SSR markers, 16 ISSR markers (with 76 polymorph alleles), two IRAP markers (7 polymorph alleles) and an iPBS marker (with 3 polymorph alleles) on 74 F8 population attributed the markers to 12 groups with a map length of 1491 cM and a distance between flanked markers of 13.07 cM. Results and discussion Under normal conditions, nine genetic locations were detected. For the root length of five genetic locations, three, five (two cases), six and seven chromosomes were identified and four gene locations were identified for stem length, located on chromosomes 1, 5 (two cases) and 7 . qPLNO-1 and qPLNO-5b were able to justify 11.46% and 12.25% of the phenotypic variance, respectively. Two genetic locations were detected in mannitol for cholectile length on chromosome 6. For the root length of the seven QTLs, they were located on chromosomes 3, 4, 6 and 7. For stem length, four gene locations were detected on chromosomes 4 and 6, which justified 8 to 11 percent of the phenotypic variation of the trait. Two genetic locations for the root length were detected on chromosomes 5 and 8, while qRASA-8 was able to justify 14.9% of phenotypic changes in the trait. Six stroke locations were detected for stem length, which were located on chromosomes 5 (three cases), 7 (two cases) and 8, respectively 8.8, 9.5, 11.25, 9.8, 13.6% and 15.7% of the phenotypic changes justify the attribute. In the drought stress condition of polyethylene glycol, a gene site was detected for germination percentage on chromosome 2 and at 78 centimeters from the beginning of the chromosome, which justifies 10.3% of the phenotypic variation of the trait. Conclusion Under normal conditions, five gene locations were detected for root length and four gene locations for stem length. For the root length, nine genetic locations were detected and for 11 stroke locations for stem length. Under stress conditions, mannitol was detected 13 gene locations, two QTLs for coleoptile, seven QTL for root length, and four QTL for stem length. Under salinity stress conditions, two genetic locations were detected for root length-six and six gene locations for stem length. Under stress conditions from polyethylene glycol, a gene site was detected for germination percentage on chromosome 2. qCLMA-6a, aRAMA-6b and qPLMA-6b on chromosome 6 and at 52 centimeters. In normal conditions qRANO-5a for root length and qPLNO-5a for stem length at 52 cm from the beginning of chromosome 5 and had common positions among RM49 and RM39 markers. These QTLs, after determining the credibility of a suitable candidate for selection programs, help markers in the population of Iranian recombinant lines of rice.
Ahmad Majidi-Mehr; Reza Amiri-Fahliani
Abstract
Introduction Rice (Oryza sativa L.) is the main staple food for more than half the world's population, and its world consumption has reached about 505.80 million tons in 2017 (IRRI, 2018). Rice cultivation has a special importance in Iran and its harvest area is estimated about 859100 hectares (Agricultural ...
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Introduction Rice (Oryza sativa L.) is the main staple food for more than half the world's population, and its world consumption has reached about 505.80 million tons in 2017 (IRRI, 2018). Rice cultivation has a special importance in Iran and its harvest area is estimated about 859100 hectares (Agricultural Statistics, 2017). Salinity is one of the environmental stressors that threaten not only the growth of plants, but also the extent of the distribution and diversity of plants in different ecosystems (Ismail and Horie, 2017). Currently, half of the arable lands of Iran (9.59 million hectares) are affected by salinity, which has a major impact on culturing area, and amount of the crop production, (Nabiollahi et al., 2017). Thus, the aim of this study was to evaluate the genetic variation, Heritability and Genetic Advance of among rice genotypes in terms of physiological characteristics and selection of the best parents for use in rice hybridization programs. Material and Method In order to study of diversity among 11 rice genotypes under salt stress condition plotted in an experiment as a split-plot based on randomized complete block design with three replications in summer 2012, at the farm of college of Agriculture, Yasouj University. The main plots were considered for 4 levels of salinity (0, 44, 88 and 132 mM), and the subplots for 11 rice genotypes including Gharib, Local Yasouj, Champa and Shahri Loudab, 304, Lenjan- Askari, Kamfirooze, Domsiah mamasani, Mossa-Tarom, Hassan-Serayi. The physiological parameters (F0, Fm, Fv, Fv/Fm, chlorophyll, soluble carbohydrates, protein and proline leaves) were evaluated one month after salinity stress application. Characteristics of chlorophyll fluorescence (F0, Fm, Fv, Fv/Fm) and chlorophyll leaves were recorded using a Flow cytometry Model (OS1-FL). Irigoyen et al (Irigoyen et al., 1992) method used for measurement of leaf soluble carbohydrates, Paquine and Lechasseur, (Paquine and Lechasseur, 1979) method for leaf proline, and Liu and Zhang (2000) method for leaf protein. At maturity stage, 2 plants of each pot were selected, and then plant grain yield was measured as the number of grains per spike. Results and DiscussionStudy of the genetic and phenotypic variation coefficients in salinity stress conditions showed that the maximum and minimum of these coefficients were belonged to grain yield and fluorescence characteristics, respectively. Grain yield under stress conditions showed a positive and significant correlation with Fv, chlorophyll and Fv / Fm, indicating that with increasing leaf chlorophyll content and Fv / Fm leaves, more photosynthesis is carried out,and thus the grain yield increases., leaf protein content had the highest, and F0 the lowest broad sense heritability, under stress conditions. Based on the results of cluster analysis, using the minimum variance method based on the 12 Euclidean distance, the genotypes under both stress and stress conditions were classified into 4 separate groups. In salinity stress conditions, a cross between the genotypes of the first and the fourth groups, which have the highest genetic distance in terms of the studied physiological traits, can be used for hybridization programs, transgressive segregation, and other breeding programs for finding tolerant genotypes to salinity. Conclusion In general, due to the results of cluster analysis in salinity stress conditions, in order to create dwarf, early and high yielding genotypes, the genotypes in the first and the fourth clusters can be considered as suitable and parents in the necessary and targeted crosses between them for improvement the important Physiological characteristics, and to access to the superior salinity tolerant and high product genotypes.
Hamideh Zare; Kazem Poustini; Reza Abbasi
Abstract
Introduction Salinity is a major abiotic stress limiting growth and productivity of plants in many areas of the world due to increasing use of poor quality of water for irrigation and soil salinization. The over increasing salinity of land and water resources is one of the most important problems in ...
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Introduction Salinity is a major abiotic stress limiting growth and productivity of plants in many areas of the world due to increasing use of poor quality of water for irrigation and soil salinization. The over increasing salinity of land and water resources is one of the most important problems in Iran’s agriculture. A key characteristic of plant development is its plasticity in response to various changing environmental conditions. Roots are important to plants for a wide variety of processes, including nutrient and water uptake, anchoring and mechanical support, storage functions, and as the major interface between the plant and various biotic and abiotic factors in the soil environment. Congregated information on wheat root system as influenced by saline condition is meager. Materials and methodsIn order to investigate the effect of salinity on some root characteristics and ion distribution, a research was carried out in a three-replicate split factorial with two salinity levels 2dsm-1 (control) and 16dsm-1 (salinity) on six wheat cultivars (Atrak , Pishtaz, Chamran, Roshan, Ghods and Shiraz) and in two levels of harvest (two weeks and three weeks after planting) in greenhouse. The traits of root dry weight, shoot dry weight, shoot dry weight/root dry weight ratio, root length, total volume, sodium, potassium and potassium / sodium ratio in root and shoot, number of main root and number of first and second- order lateral roots were measured. Results and discussion The results showed that salinity in the second and third week reduced the dry weight of root, shoot, length, root volume and root number in all cultivars. Regarding the reduction and amount of root and shoot dry weight, Qods cultivar is susceptible and Roshan cultivar is tolerant. Also, Chamran and Roshan cultivar had a high ability to produce root and shoot in the control treatment, respectively. Qods cultivar under salt stress in the second and third week showed the highest reduction in total root length compared to control treatment and also, it had the least root length in salinity treatment compared to other cultivars. In the second and third weeks, Qods for root production (main, first and second-order lateral root) produced a high root count in the control treatment. However, as a result of salinity, the number of first and second-order lateral roots was significantly reduced, and in this trait it was the most sensitive cultivar. Under salinity Shiraz cultivar maintained in the third week of rooting process and showed the lowest reduction in the number of first and second-order lateral roots. In Roshan and Qods cultivar, there was no significant difference in the level of sodium ion in root in control and salinity treatments in the second and third weeks. This indicates that the accumulation of sodium ion in the root is not affected by salinity. The Roshan cultivar in saline treatment was able to maintain potassium ion in roots and shoots every two weeks. Shiraz and Pishtaz cultivars at the beginning of stress are able to avoid its negative effects by not absorbing sodium, although they are affected by ionic effects by continuity of tension and sodium absorption.
bahare eskandari; Goudarz Ahmadvand; Mohammad Ali Abutalebian
Abstract
Introduction Seed germination is first critical and the most sensitive step in the life cycle of plants. Germination of weeds has an important role in its establishment in an agricultural and seed germination and seedling establishment are critical and important stages in plant life cycle caused by environmental ...
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Introduction Seed germination is first critical and the most sensitive step in the life cycle of plants. Germination of weeds has an important role in its establishment in an agricultural and seed germination and seedling establishment are critical and important stages in plant life cycle caused by environmental factors such as salinity, humidity, temperature, light and pH soil is regulated. If a plant that can show greater resistance to environmental stresses in the germination stage will be able to make its first course more successful. Usually, the most susceptibility to stress in the plant life cycle occurs during germination and at the beginning of seedling. Material and method Datura innoxia L. seeds were prepared from Agricultural Research Bahar University, Hamedan, Iran. Seeds were sterilized with 5% sodium hypochlorite solution for 5 min. Followed by washing with distilled water. Therefore, they were transferred to 9 cm diameter sterilized petri plate containing single layer of filter paper. Salinity stress was induced by using sodium chloride (NaCl) and drought stress by using Polyethylene Glycol (PEG-6000). Five ml NaCl solution and PEG-6000 (-0.2, -0.4, -0.6, -0.8, -1 MPa) were added in different petri plates. The control or (0) contained five ml of sterile distilled water. Each treatment was maintained in six replicas along with control. To study the effect of pH on germination, pH solutions with acidity of 4 to 9, and depth effect on seeds cultivated at depths of 0, 2, 4, 6, 8 and 10 cm. Germination was carried out in a germination chamber with a regime of 24 h dark at 25 °C. Results and discussion Analysis of variance of the effects of salinity and drought stress on seed germination of D. innoxia suggested that these treatments made significant changes at (p < 0.05). The reduction in seed germination was proportional to the increasing concentration of NaCl and PEG. Maximum retardation was noted at highest NaCl concentration and PEG 6000 (-1 MPa). With the increasing intensity of drought and salinity from 0 to -1 MPa D. innoxia germination percentage of 100 percent respectively compared to control was reduced. Fitting of three-parameter logistic model, provided a successful estimation of the relationship between salt and drought stress levels and germination percentage of D. innoxia as well as germination speed. This model showed that salinity and drought stress at -0.39 and –0.27 MPa, respectively caused 50% reduction in maximum germination percentage of D. innoxia. In addition 50% decrease in germination speed caused by salinity and drought stress, were observed in -0.33 and -0.28 MPa, respectively. The optimum pH for germination was 7 and the pH increased by decreasing the germination percentage. The highest percentage of emergence of in surface soil seeds was 73.33% and with increasing soil depth the percentage of seedling emergence decreased. Only 3% of the seeds are able to germinate from a depth of 8 cm. Conclusion This research revealed that D. innoxia differed significantly in its response to salt and drought stress. D. innoxia is more sensitive to drought stress at germination stage. However, at early growth stage both salt induced osmotic stress and Na toxicity reduced growth. For better management of this weed in farms and gardens, we can use tillage operations so that seeds are transmitted at a depth of more than 8 cm and can prevent the emergence of this weed. In alkaline environments, germination of the plant decreases.
Somaye Asadi; Mohammad Moghaddam; Abdollah Ghasemi Pirbaloti; Amir Fotovat
Abstract
Introduction The presence of heavy metals in the environment of plants is a stressful agent that causes physiological changes and can reduce plant growth potential and, in a more severe condition, cause it to disappear. Lead is one of the toxic metals for humans, as well as unnecessary for plants. Due ...
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Introduction The presence of heavy metals in the environment of plants is a stressful agent that causes physiological changes and can reduce plant growth potential and, in a more severe condition, cause it to disappear. Lead is one of the toxic metals for humans, as well as unnecessary for plants. Due to the solubility of this element in water, it is easily absorbed by the root system of the plant. In this way, the growth and metabolism of the plants are affected by the increase of these metals in the environment. This metal disrupts plant growth, root growth, seed germination, seedling development, transpiration, and cell division. Lead toxicity reduces the growth and yield of the product, jaundice of young leaves, decreases the absorption of certain essential elements, such as iron and reduces photosynthesis. The use of plant growth regulators to reduce the absorption and accumulation of heavy metals in plants can be a suitable method for reducing the related damages. Jasmonates play a regulative role in the development and response to environmental stresses and reduce the damage caused by these stresses in the plant.Basil (Ocimum basilicum L.) belongs to the family Lamiaceae and is one of the medicinal plants and valuable herbs that are cultivated throughout the world. This plant is widely used in medicine and industry. The purpose of this study was to investigate the effect of lead toxicity on growth characteristics and its absorption in aerial parts and roots and the effect of methyl iasmonate as a growth regulator on these characteristics. Material and methods This research was carried out in greenhouse of Faculty of Agriculture, Ferdowsi University of Mashhad during spring and summer of 2015, as a pot factorial experiment in a completely randomized design with three replications. The treatments consisted of three levels of lead nitrate (Pb(NO3)2) (0 (control), 200 and 400 mg/kg soil) and three levels of methyl jasmonate (zero (control), 0.5 and 1 mM ) which was applied as spraying. The evaluated traits included plant height, inflorescence length, number of branches, number of nodes, internode length, leaf length and width, stem diameter, fresh and dry weight of aerial parts and root fresh and dry weight, as well as lead accumulation in aerial parts and roots were measured at flowering stage. Results and discussion The results of analysis of variance showed that the interaction of treatments on the length of flowering, number of branches, fresh and dry weight of aerial part and root fresh weight at 5% probability level, and on root dry weight and lead absorption in aerial part and root of the plant was significant at 1% probability level. Whereas the interaction of treatments on plant height, leaf length and width, stem diameter, number of nodes and internode length was not significant. In plants treated with lead, number of branches per plant, inflorescence length, fresh and dry weight of aerial part and root showed a significant decrease compared to control plants and application of 0.5 mM methyl jasmonate in lead stress conditions improved these traits. Growth of plants in the medium containing lead was caused accumulation this element in the aerial part and root, so that the lead concentration in the aerial part was higher than the root, and methyl jasmonate in both concentrations reduced the accumulation of lead in the root and aerial parts of basil. Khudsar et al. (2000) reported that the interaction of heavy metals with sulfidryl groups and the inactivation of plant proteins prevents growth of aerial part and root. Disruption of hormone activity, such as auxin, in heavy metals treatment can also reduce plant growth (Potters et al., 2007). Lead contributes to water stress and thus reduces leaf area, photosynthesis, plant dry weight and plant height, and the number of nodes (Azmat et al., 2006). Regarding the role of methyl jasmonate in reducing lead accumulation, it can be said that this growth regulator activates as a signal molecule the expression of the genes involved in plant defense mechanisms, including the biosynthesis pathway of phytolatin, which connections to toxic ions and convert them to non-toxic ions. Based on the results of this study, it seems that the basil is susceptible to the storage of heavy metals such as lead in its leaves, which can be reduced by using appropriate concentrations of methyl jasmonate.
Mehdi Karimi; Majid Nikkhah
Abstract
IntroductionAs a micronutrient, zinc is essential for protein and carbohydrate metabolism, auxin synthesis, membrance integrity and reproduction. Plant growth under calcareous and saline soils, charactetrized by high soil pH, is usually negatively affected due to zinc deficiency as a result of low micronutrient ...
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IntroductionAs a micronutrient, zinc is essential for protein and carbohydrate metabolism, auxin synthesis, membrance integrity and reproduction. Plant growth under calcareous and saline soils, charactetrized by high soil pH, is usually negatively affected due to zinc deficiency as a result of low micronutrient avalilability. It is reported that 56 percent of agricultural lands suffer from zinc defficiency (Shahbazi and Besharati, 2013). It is well documented that zinc fertilizers improves plants quality as well as human health (Malakouti et al., 2010). Saline soils usually result in osmotic pressur and nutrient disorders in plants and leads to plants growth decline. As a worldwide abiotic stress responsible for reduced crop production, it is estimated that annual losses of yield due to salt induced land degradation is US$ 27.3 billion globally (Qadir et al., 2014). Social and economic dimentions of salinity stress can be employment losses as well as environmental degradation (Butcher et al., 2016). While application of chemical fertilizers at arid and semiarid soils usually improves plant performance, the efficiacy of fertilizers application may be affected by salinity stress. While there is little evidence of yield benefits due to application of fertilizers in salinized fields at rates beyond optimal in non-saline conditions, there is enough evidence indicating that soil salinity does not affect or decrease plant fertilizer needs (Hanson, 2006). It is reported that zinc fertilizer improves salinity tolerance (Saedinejad et al., 2016; Ahmadi et al., 2005) and alleviates the negative effectd of salinity stress and this is due to the Na concentration reduction in wheat plants (Ahmadi et al., 2005). However, contradictory results have been reported. These contradictory results can be attributed to the types of experiments (field, greenhouse or laboratory), composition of the saline substrate, studies conducted over the short term vs. the long term and many other differences in experimental conditions (Grattan and Grieve, 1999).Thus zinc fertilizer management under arid and semiarid conditions of Yazd peovince with wide range of irrigation water qualities may need to be modified. Accordingly, the objectives of this field study were to (a) elucidate the interactions between zinc nutrition and the salinity of irrigation water and their effects on wheat growth and (b) test the possibility of wheat improvement at saline conditions by applying higher levels of zinc fertilizer. Materials and methodsA field experiment was conducted on wheat at Sadooq Salinity Research Station, Ashkezar, Yazd, Iran. The soil at the experimental site was calcareous with 30.92% total neutralizing value, sandy loam texture, pH 8.06 and 0.22 % organic carbon. Mean annual temperatue is 18°C and precipitation is 70 mm. The treatments, four zinc sulphate application rates (0, 20, 40 and 80 kg ha-1) and three irrigation water qualities (1.88, 7.22 , 14.16 dS/m), arranged in a compelet randomized block, split plot design with three repelications. Consisting 12 rows of wheat, each field plot was 3*5 m. All plots received common agricultural practices including tillage and fertilizer application. Rgarding typical recommendations and guidelines for this region and soil type (Balali et al., 2000: Moshiri et al., 2015), all fertilizers, except urea that applied in 4 splits, were soil-applied before plnating and included 100 kg ha-1 triple superphosphate, 40 kg ha-1 FeSO4,, 40 kg ha-1 MnSO4 and 20 kg ha-1 CuSO4. For modeling the relationship between plant properties and irrigation water salinity, the data were subjected to different regression models at the probability level of 0.01 and 0.05 with the help of the Sigmaplot software. The analysis of variance for different parameters was done following ANOVA technique. When F was significant at p ≤ 0.05 level, treatment means were separated using DMRT. Results and discussionThe maximum grain yield for plants irrigated with both irrigatin water salinity of 1.88 and 16.14dS/m was found at zinc sulphate application rate of 25kgha-1. In addition, wheat grain yield response to salinity stress at zinc sulphate rates of 0, 20 and 40kgha-1 were similar and followed linear regression model. Indicating the increasing salinity tolerance, the decline per unit slope decreased with increasing Zn application rates. Interestingly, wheat grain yield response to salinity stress at highest Zn application rate of 80kgha-1 followed the quadratic regression model. This observasion, also, proves that wheat response to salinity stress depends on soil fertility level. The results of this experiment showed that wheat response to salinity stress depends on soil fertility level (Zn application rate). In additions, the results showed that with increasing irrigation water salinity from 1.88 to 16.14dS/m the grain yield decreased from 6.5 to 3.5 tonnes/ha but ZnSO4 requirement was not changed. ConclusionIt was concluded that wheat response to salinity stress depends on soil fertility (zinc sulphate application rate) and salt tolerance increased by increasing zinc application rate. While salinity stress decreased wheat yiled from 6.5 to 3.5 ton ha-1, application of zinc sulphate at a rate of 20 kg ha-1 is needed for all salinity levels.
