Ali Nakhzari Moghaddam; Nadia Parsa; Hossein Sabouri; Saeed Bakhtiari
Abstract
Legumes are from important food and feed resources with rich of protein for human and animals. Pulse seeds by having 18-32% protein have important role in human food regim specially in low input human feeding (Majnoun Hosseini, 2008). Nayyar et al (2006) have believed that flowering and pod setting stages ...
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Legumes are from important food and feed resources with rich of protein for human and animals. Pulse seeds by having 18-32% protein have important role in human food regim specially in low input human feeding (Majnoun Hosseini, 2008). Nayyar et al (2006) have believed that flowering and pod setting stages are the sensitive stages of chickpea to drought and water stress at flowering stage with reducing of flowers fertility will reduce number of seeds per plant. Gad et al. (2012) reported that spraying of humic acid increased seed yield, 1000-seed weight and protein percent of peas. The aim of this study was to determine effect of density, supplementary irrigation and humic acid on quantity and quality of local chickpea )Cicer arietinum L. (of Neishabur. Materials and methods In order to study the effect of humic acid, density and supplemental irrigation on yield, yield components, protein percent and yield of local chickpea (Cicer arietinum L.) of Neishabur, an experiment carried out in factorial based on Randomized Complete Block Design with three replications in field research of Islamic Azad university of Neishabur during 2012-2013. The factors was humic acid in two levels of application and non application of humic acid, plant density was in three levels of 20, 30 and 40 plants m-2 and supplemental irrigation in three levels of non irrigation, irrigation at flowering stage and irrigation at pod setting stage. In this study seeds were plated by hand. Each plot included five rows with four meters legth, row spacing 25 cm, plant distance on row based on density 20, 13.3 and 10 cm (20, 30 and 40 plants/m2, respectively). 10 plants were selected randomizedly from each plot and pods/plant, seeds/plant, 100-seed weight, plant yield and protein percent were measured. For determining of seed yield, two border rows and 0.5 m from two ends of middle rows were removed and remains were harvested and were put in oven for 48 hours in 70 °C and then were measured. For analysis variance of data software of SAS Ver.9.1.3 were used and treatment mean differences were separated by the least significant difference (LSD) test at the 0.05 probability level. Results and discussion The effect of humic acid and density on all traits except 100- seed weight and protein percent was significant. All traits were affected by supplemental irrigation. Interaction of acid humic × supplemental irrigation on pods/plant, seeds/plant, plant yield, seed yield and protein yield ha-1 and interaction of density × supplemental irrigation on seeds/plant and plant yield was significant. Consumption of humic acid increased all traits. Seed yield in cosumption and non cosumption of humic acid was 2234 and 1752 kg ha-1, respectively. Increasing of density reduced yield components but seed yield and protein yield ha-1 were increased. Seed and protein yield in density of 40 plants m-2 was 2264 and 521.4 kg ha-1 respevtively. Irrigation increased all traits except protein percent. Seed yield in treatments of irrigation in flowering and pod setting stages was 2417 and 2330 and protein yield was 561 and 531.9 kg ha-1, respectively. In this study, maximum seed and protein yield were obtained by consumption of humic acid and supplemental irrigation at flowering stage with 2697 and 638.2 kg ha-1 that have not differences with cosumption of humic acid and irrigation at pod setting stage with 2648 and 615.3 kg ha-1. Maximum seed and protein yield with 2264 and 521.4 kg ha-1 belonged to treatment of 40 plants m-2. Conclusion Humic acid and spacially density and supplemental irrigation affected chickpea seed and protein yield. Although by increasing of density yield components were decreased but, seed yield were increased. Irrigation at flowering stage had the highest effect on traits. Non irrigation increased protein percent but, protein yield in this treatment because of lower yield of chickpea was less than other treatments.
Shams-oldin Skandarnejad; Manoochehr Gholipoor; Hasan Makarian
Abstract
Introduction Water shortage is one of the most important abiotic stresses which impose deleterious effect of growth and yield of crops including mung bean. Part of this effect comes from over production of reactive oxygen species (ROS) including OH·, O2·-, and H2O2. Crops try to scavenge ...
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Introduction Water shortage is one of the most important abiotic stresses which impose deleterious effect of growth and yield of crops including mung bean. Part of this effect comes from over production of reactive oxygen species (ROS) including OH·, O2·-, and H2O2. Crops try to scavenge these ROS using antioxidant enzymes like superoxide dismutase, guaiacol proxidase and catalase. This experiment was aimed to study the sensitivity of some traits of Mung Bean to water shortage and to see whether the activity of catalase, superoxide dismutase and guaiacol proxidase antioxidant enzymes is the same under different water shortage intensities or not. Materials and methods An experiment was conducted using pots with 5 kg capacity in which 5 seeds of mung bean were planted. The pots were put in an open filed to increase the possibility of generalizing the results to field results. At 4-leaf stage, 2 seedlings were removed, and left 3 ones. Treatment levels were control, weak water shortage [irrigation at 65% field capacity (FC)], moderate water shortage (irrigation at 50% FC), and severe water shortage (irrigation at 35% FC) which arranged as on completely randomized block design with 3 replications. At maturity stage, some attributes including biological yield, plant height, number of seed per pod, number of pod per plant, grain yield, and length of pod were measured. The sensitivity index of these attributes to water shortage was calculated using appropriate functions to test whether these attributed differ in terms of value of response to drought or not. For measuring the activity of 3 antioxidant enzymes, the plant samples were taken at flowering stage. Then the activity of catalase, superoxide dismutase, and guaiacol proxidase enzymes were measured as it has been presented in report of Havir and McHale (1987), Van Rossun et al. (1997), and Cavalcanti et al. (2004), respectively. Results and discussion Results indicated that all measured attributes were significantly affected by water shortage. It was found a low-sloped decreasing trend with increasing water shortage intensity in pod length. The value of plant height for plants experienced weak water shortage was statistically similar to those grown in no water shortage conditions (control). But it decreased sharply for plants treated with medium and severe water shortages. The sensitivity threshold of number of seed per pod was relatively high; because over the field capacities equal to 50% and greater than that, its quantity was similar to control. The sensitivity index of this attribute and number of pod per plant was 0.050182 and 0.038788, respectively. Considering the standard errors of these indices, the difference between number of seed per pod and number of pod per plant for quantitative response to water shortage is statistically negligible. The quantity of both biological yield (straw + grain) and grain yield appeared to be not changed in weak water shortage as compared to no water shortage conditions. Then after, they were negatively affected. Under severe water shortage condition, the percent of decrease in grain yield was higher than in biological yield. The sensitivity index of them was 0.120727 and 0.031512, respectively. The grain weight accumulation is dependent on current photosynthesis and non-structural carbohydrates stored in vegetative organs like stem before flowering. The activity of hydrolytic enzymes including alpha amylase is crucial. The higher decrease in grain yield than in biological yield may imply that the activity of these enzymes has also been negatively affected. Under weak and medium water shortage conditions it was found no change in activity of catalase as compared to control. But under severe water shortage condition, its activity was considerably (3 times) increased. The activity of superoxide dismutase was constant over control and weak water shortage situations; but it doubled under medium water shortage conditions. The guaiacol peroxidase activity did not respond to weak water shortage; subsequently, it showed an upward trend. Conclusion Grain yield and plant height were the most sensitive traits. Number of seed per pod, number of pod per plant and biological yield with statistically similar values of sensitivity were in 2nd order. The length of pod was the most tolerant trait as it tended to have the lowest sensitivity index. The increase in activity of superoxide dismutase was being witnessed in moderate water shortage. For catalase, it was true only for severe water shortage. The activity of guaiacol porxidase was statistically the same under control and weak water shortage conditions. But its activity increased proportionally with increasing water shortage intensity.
Farzaneh Golestani Far; Sohrab Mahmoodi; Gholam Reza Zamani; Mohammad Hasan Sayyari Zahan
Abstract
Introduction Weed is unwanted and harmful plant which annoyed or barrier in agricultural operations and increase the cost of the kept and reducing crop yields. Weeds often compete with crops for limited resources such as soil water and reduced water availability in crops. One of the important principles ...
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Introduction Weed is unwanted and harmful plant which annoyed or barrier in agricultural operations and increase the cost of the kept and reducing crop yields. Weeds often compete with crops for limited resources such as soil water and reduced water availability in crops. One of the important principles of integrated weeds management is the development of strategies for weed control based on recognition of the interaction between crop and weeds and quantity competition between crops and weeds is requisite for weed management decisions. One of the valid models for estimating the amount of competition between two species in mixed culture is the reciprocal method of one plant yield. Wheat in terms of production and Cultivated area is the most important of crops in Iran and world. Wheat production in world is about 728.8 million tons in 2015-2016. Weed problem in wheat is one of the most important agricultural issues in wheat growing areas of world and Plant community combination of wheat weeds are a reflection of planting season, agronomic and chemical weed control, geographical region and type of soil. In Iran many areas that under cultivated wheat faced with rye. Low expectations of rye with the ability of allelopathic and Morphology and similar life cycle with wheat, caused increasing of its area in winter wheat fields. Materials and methods In order to study the evaluation of competitive parameters of Wheat and Rye under drought stress condition by using reciprocal yield model, a pot experiment was conducted in the greenhouse of Agriculture College at University of Birjand in 2012. The experiment arranged as factorial based on completely randomized design with three replications. The factors including four wheat density: 0, 8, 16, 24 plants / pot, four rye density: 0, 2, 4, 6 plants / pot and two levels of drought stress: irrigation after depletion of 20 and 60% of field capacity moisture.Models of reciprocal yield were fitted based on biological yield of one wheat plant and rye in two moisture levels and Relation reciprocal biological yield of one wheat plant and rye was obtained with density of two plants by using multivariate linear regression. Also relative competitive ability and Nich differentiation Index calculated by the coefficients of inter and intra specific competition. Results and discussion The result of reciprocal yield model showed that wheat had greater inter-specific competition than intra-specific, but in rye intra-specific was higher. The ability index of relative competition exhibited that effect of a wheat plant in 20 and 60% depletion of soil moisture was equal to effect of 0.79 and 0.64 of a rye plant, respectively. So, effect of a rye plant at the same moisture level was equal to 1.85 and 2.43 of a wheat plant, respectively. Ecological niche differentiation index of both plants was obtained less than 1 in each of two moisture levels. So that the Nich differentiation Index in 20 and 60% of field capacity moisture was about of 1.46 and 1.55 respectively. Conclusion Relative competitive ability or rye and wheat with increasing drought stress increased and decreased, respectively. Biological yield of wheat more affected by inter-specific competition as a result rye compared to wheat was stronger competitor. Combined effects of drought stress and rye competition significantly decreased biological yield of wheat. Generally, under drought stress, intensity of intra and inter specific competition increased between rye and wheat plants and resulted to decreasing of biological yield of those plants. As a result, control of rye in drought stress condition is very important in wheat fields.
Ahmad Reza Dehghani Tafti; Hossein Shamsi; Abolfazl Morovati; Mohammad Javad Babaei Zarch; Mohammad Hasan Dehghani Tafti
Abstract
Introduction Drought stress is one of the most important abiotic stress that leads to decreasing yield of crops, particular cereals, not only in Iran but also around the world. Accessing to sufficient nutrients like potassium is one of the ways that increase crop resistance. Potassium is an essential ...
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Introduction Drought stress is one of the most important abiotic stress that leads to decreasing yield of crops, particular cereals, not only in Iran but also around the world. Accessing to sufficient nutrients like potassium is one of the ways that increase crop resistance. Potassium is an essential element to growing plants. This element is a multitasking nutrient in plants that use in activation of enzymes, osmotic control, carbohydrate production and partitioning and anion cation balance. So because of Hulless Barley importance for human, animals and birds feed, drought expansion in Iran and around the world, importance of potassium element to decrease drought stress effects, metabolic process improvement and plant photosynthesis, an experiment to find out the effects of drought stress and potassium on yield and yield components of Hulless Barley conducted. Materials and methods To find out effects of different irrigation regimes and different amounts of potassium on yield and yield components of Hulless Barley, a split plot experiment based on randomized complete block design with three replicates was conducted at the Research Farm of Islamic Azad University, Meybod Branch in 2012. Each block was consist of 3 main plots and 4 sub plots in each main plot. Main plot was consist of irrigation cycles: 7 days irrigation (control), 14 days irrigation (moderate stress) and 21 days irrigation (extreme stress). Sub plot was consist of 4 levels nutrient elements: 0, 100, 200 and 300 kg.ha-1 potassium sulphate. Different potassium levels were applied before sowing. At the end of growing season, grain yield, straw yield, biological yield measured. Also Fertile tiller number, grain number per spike and 1000 grain weight of Hulless Barley measured as yield components. Results and discussion Results showed that most yeild(3147.5 kg.h-1) and yield components achieved in 7 days irrigation cycle. Yield components decreased 12 and 43 percentage by increasing irrigation cycle to 14 and 21 days. Seed yield was 2761 and 1792 kg.h-1 at 14 and 21 irrigation cycle. Also potassium sulfate application improved agricultural characteristics and decreased negative effects of drought stress. Result showed that increase potassium sulphate application from 0 upto 300 kg.h-1 had significant effect on seed yield, but there was no significant difference between 200 and 300 kg.h-1 application. Maximum harvest index (36.1%) achieved at 200 kg.h-1 potassium sulphate applications. Minimum harvest index (32%) achieved at 0 kg.h-1 potassium sulphate applications. Maximum fertile tillers (1.2) was in 7 days irrigation cycle + 200 kg.h-1 potassium sulphate applications and minimum fertile tiller was in 21 days irrigation cycle + 200 kg.h-1 potassium sulphate applications. In 7 days irrigation cycle and 14 days irrigation cycle, 100 kg.h-1 potassium sulphate applications caused to increasing fertile tiller number. More potassium sulphate application had no significant effect on fertile tiller number. Also results showed that increase potassium sulphate application from 0 upto 100 kg.h-1 lead to increasing grain number per spike from 26.6 to 31. Among different amounts of potassium suphate application, no potassium sulphate application treatment had the lowest (30.9 gr) 1000 grain weight and 300 kg.h-1 potassium sulphate applications had highest (34 gr) 1000 grain weight. Conclusion Results showed in no water limitation condition recommended 7 days irrigation cycle for maximum yield. Results showed Hulless Barley can tolerate moderate water stress, so in water limitation condition 14 days irrigation cycle application can suggest for achievement acceptable biological yield of Hulless Barley. According to this experiment results, potassium nutrition can improve yield characteristics in water limitation. There was no significant difference between 200 or 300 kg.h-1 potassium sulphate application, so for reduce negative enviromental effects, 200 kg.h-1 potassium sulphate application can suggest for achievement acceptable yield of Hulless Barley.
Amin Mohammadi; S. Gholam Reza Moosavi; Mohammad Javad Seghatoleslami
Abstract
Introduction Iran with mean annual precipitation of 240 mm is categorized in arid and semi-arid zones of the world. High evapotranspiration and limitation of water resources are important environmental parameters that caused reduction of the plants yield in Iran. Also nitrogen deficiency affects the ...
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Introduction Iran with mean annual precipitation of 240 mm is categorized in arid and semi-arid zones of the world. High evapotranspiration and limitation of water resources are important environmental parameters that caused reduction of the plants yield in Iran. Also nitrogen deficiency affects the partitioning of assimilates among vegetative and reproductive organs and can influence the growth and yield of the plants. Therefore, given the importance and different roles of water and nitrogen in vital processes of the plants, the objective of the present research was to study the effect of irrigation interval and N fertilizer application on morphological traits, yield and yield components of millet in Birjand, Iran. Materials and Methods This research was conducted as split-plots based on a Randomized Complete Block Design with three replications, at Agricultural Research Center of Birjand branch, Islamic Azad University in 2009. The main plots included irrigation interval at three levels (7, 14 and 21 days) and the sub-plots were N fertilizer application at five levels (control or 0 kg N. ha-1, 50 kg N. ha-1, 50 kg N. ha-1 + foliar application, 100 kg N. ha-1 and 100 kg N. ha-1 + foliar application kg N. ha-1). The texture of the soil in research farm was loam with the pH of 8, electrical conductivity of 4.49 mmhos cm-1 whose organic carbon, total N, P, and K content was 0.32%, 0.08%, 16.4 ppm and 501 ppm at the depth of 0-30 cm, respectively. In the end, all data were analyzed by MSTAT-C statistical software and means were compared by Duncan Multiple Range Test at 5% level. Results and Discussion The results of analysis of variance indicated that the effect of irrigation interval on plant height, panicle number per m2, 1000-seed weight, seed yield and biological yield were significant. Also, plant height, flag leaf area, panicle number per m2 and seed yield were significantly affected by nitrogen levels. Interaction of irrigation interval and N fertilizer only significantly affected1000-seed weight. Means comparison indicated that the increase in irrigation interval from 7 to 21 days decreased plant height, flag leaf area, panicle number per m2, 1000-seed weight, seed yield and biological yield, 36.8, 33.6, 32.9, 18.5, 44.4 and 40.1 percent respectively. Also, 50 kg N. ha-1 + foliar application treatment increased plant height, flag leaf area, panicle number per m2 and seed yield, 20.4, 21.9, 47.8 and 52.3 percent, respectively as comparison with non-nitrogen application treatment. It is seems that water deficit stress, due to its effect on photosynthesis, respiration, ionic absorption, nutrients and hormones metabolism processes reduced the growth of stem and leaf cells and decreased leaf area and led to a decrease in flowering and grain filling period which finally caused reduction of yield and yield components. Probably, the decrease in leaf area is a response to stress for adapting water deficit conditions and survival through decreasing transpiring area of the plant. Moreover, with the increase in N application, plant photosynthesizing area and assimilate production increased and therefore seed yield increased. Conclusions In total, the results of the current study indicated that water and nitrogen deficiency significantly decreased millet economical yield mainly by decreasing panicle number per m2. Finally, results of research showed that treatment of 7 days irrigation interval and 50 kg N. ha-1 + foliar application recommended for the cultivation of millet in Birjand region for production maximum of millet seed.
Maryam Saleminanasab; Manochehr Gholipoor; Hasan Makarian; Hasan Ariani-Mohammadi
Abstract
Introduction Ultrasound wave application is known as a novel technology. It is widely used for many purposes including industry, agriculture (e.g. plant breeding, raisin processing) and food technology. The experimental evidences regarding the irradiation of seeds with ultrasound have shown extraordinary ...
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Introduction Ultrasound wave application is known as a novel technology. It is widely used for many purposes including industry, agriculture (e.g. plant breeding, raisin processing) and food technology. The experimental evidences regarding the irradiation of seeds with ultrasound have shown extraordinary results in affecting seedling growth. For instances, it has been reported that irradiation of seeds for 50 to 60 seconds increases the germination percent, radical and plumule length by 40, 32 and 5-8%, respectively (Fariabi et al., 2008). Irradiation of Myrtus communis has resulted in breaking seed dormancy, increasing germination rate and boosting seedling dry weight (Alvandian et al., 2013). Most of irradiation- related experiments have focused on seed germination and early seedling growth. Therefore there are no published reports regarding its possible effects on the plant at rest of growth and development stages. Considering the positive effect of irradiation on radical growth, it is hypothesized that such effect sustains even in adult stages of growth and development. Therefore, due to possible deeper rooting system, an increased drought resistance is expected. This filed experiment was aimed at investigation of possible alleviating effect of irradiation on decreasing impacts of drought stress on corn. Materials and methods The variety of corn was SC740. The experiment was as factorial based on complete block design with 3 replications. Treatments were drought durations [control, long-term stress (no irrigation from flowering onward), and short-term stress (no irrigation from seed dough-stage onward)] and irradiation of seeds (control, 2, 4, 6, and 8 minutes) with ultrasound. The traits including leaf area index, relative water content (RWC), leaf carotenoid content, soluble sugar content of leaf and leaf K content were measured 10 days after seed dough stage. After maturity, seed protein content, shoot biomass and grain yield were measured. Results and discussion The results indicated that, among source of variations, say experimental factors in ANOVA table, only the effects drought and irradiation were significant on RWC. The decrease in RWC was 13 and 19% for short and long duration drought stress, respectively. Six minutes irradiation was the best level which increased RWC by 18% compared to control. Surprisingly, leaf area index was not affected by irradiation. But it significantly responded to drought stress with probability level of 1%. The drought- resulted decrease in leaf area index was 25 and 27% for short term and long term cutting of irrigation. The difference of drought levels for leaf area index was statistically negligible. Accordingly, it seems that they may differ for lead thickness (say leaf dry weight) than leaf area. The highest content of K in leaf was obtained for long-term stressed plants (299.33 mg.g-1). Irradiated plants (say seeds) by 6 minutes had 14% higher leaf K content than control. Regarding leaf content of soluble sugars, the short drought stress appeared to be most effective. Its content was the lowest for non-stressed plants. Among irradiation levels, again 6-minute irradiation was the best as it increased leaf K content by 22%. The leaf carotenoid content was only showed response to drought stress. It tended to have decreasing trend with increasing drought stress duration. It is believed that in response to drought stress, carotenoid content gets increased, but subsequently shows decrease which is kind of plant adaptation to stress (Young, 1991). Seed protein content had significant response to both main and interactive effects of factors. This proves that the effect of drought stress on the mentioned trait is not the same for plants irradiated differently. For example, under 2 and 8 minutes irradiation conditions, seed protein content was lower for stressed plants when compared to non-stressed ones. But it was vice-versa for 6 minutes irradiation. The highest seed protein content was obtained for combination of long term drought stress and 6 minutes irradiation. The decrease in biomass was 24 and 31% for short and long drought stress, respectively. For grain yield, it appeared to be 18 and 34%, respectively. The best irradiation level, i.e. 6-minute one, positively affected the biomass and grain yield by 13 and 25%, respectively. Conclusion The interactive effects of drought and irradiation were not significant on some traits including biomass and grain yield. This finding shows that the positive effect of irradiation on growth of corn did not differ statistically for stressed and non-stressed conditions. In another words, irradiation of seeds as long as 6 minutes could increase growth of both stressed and non-stressed corn. This is equivalent to alleviation of drought stress impacts on corn. This alleviation might be due to increased leaf K content (14%), and enhanced leaf concentration of soluble sugars (22%), and consequently promoted pant water status (18% increase in RWC).
Anita Yaghotipoor; Ezzat Allah Farshadfar; Mohsen Saeidi
Abstract
Introduction Selection index of ideal genotype (SIIG) technique, proposed in this paper, is one that is very simple and easy to implement. According to this technique, the best genotype would be the one that has the least deviation from the positive ideal parameter and the most deviation from the negative ...
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Introduction Selection index of ideal genotype (SIIG) technique, proposed in this paper, is one that is very simple and easy to implement. According to this technique, the best genotype would be the one that has the least deviation from the positive ideal parameter and the most deviation from the negative ideal parameter. The positive ideal parameter is a parameter with maximizes drought tolerance and minimizes drought tolerance, whereas the negative ideal parameter is a parameter with stress susceptibility. In fact, SIIG technique is derived from technique for order preference by similarity to ideal solution (TOPSIS) method (Hwang and Yoon, 1981). If for selection of drought tolerance genotypes, researchers can be used several methods simultaneously, presumably will increase the efficiency of selection (Zali, et al., 2015). SIIG technique that was proposed in this paper is a method that can select drought tolerance genotypes using different procedures. Materials and methods 20 genotypes were tested in randomized complete block design with three replications at the experimental farm of Faculty of Agriculture, Razi University of Kermanshah, Iran in 2014-2015. The SIIG technique is composed of the following steps: Step 1: Construct normalized selection matrix: The normalization of the decision matrix was done using the following transformation for each rij. r= x ∑ x i=1,…,n; j=1,…,m. Where rij is the normalized stability methods or different trait value. D=x x x x x x⋮ ⋮x x x →R =r r r r r r⋮ ⋮r r r Step 2: Determine the positive ideal parameter (maximum stability) and negative ideal parameter (minimum stability) genotypes: The positive ideal and negative ideal parameters are determined, respectively, as follows: A={r,r,…,r} A= maxrj∈Ω ,minr|j∈jΩ Where Ω is the set of maximum stability and Ω is the set of minimum instability. A={r,r,…,r} A= minrj∈Ω ,maxr|j∈jΩ Where Ω is the set of minimum stability and Ω is the set of maximum instability. Step 3: Calculate the segregation measures for each genotype: The two Euclidean distances for each genotype were calculated. The separation of each stability value from the positive ideal parameter is given as: d= (r−r) i=1,…,n Similarly, the separation from the negative ideal parameter is given as: d= (r−r) i=1,…,n Step 4: Calculate the relative closeness to the ideal parameter: The relative closeness (for selection stable genotypes) to the ideal parameters can be defined as: SIIG= d d+d i=1,2…,m, 0≤SIIG≤1. Results and discussion Twelve drought tolerance indices includingmodified stress tolerance index(MSTI), yield stability index(YSI), yield index(YI), stress susceptibility index(SSI), stress tolerance index(STI), tolerance index(TOL), geometric meanproductivity(GMP),harmonic mean(HAM), mean productivity(MP), drought resistance index(DI), relative drought index(RDI) and also selection index of ideal genotype were calculated. Using these indicators and priniciple component analysis genotypes 1, 12 and 15 were selected as tolerant genotypes. It is also 1, 12 and 15 genotypes with the highest selection index of ideal genotype values, near to one was accepted drought tolerance genotype, also 4 genotype with the lowest selection index of ideal genotype value, near to zero was accepted drought susceptible. The results were the same in different ways. Modified stress tolerance index, harmonic mean, mean productivity, stress tolerance index and geometric meanproductivity the harmonic mean and K1STI significant positive correlation with yield in stress and non-stress conditions were therefore the best indices to identify superior genotype. Conclusion The selection index of ideal genotype (SIIG) is a selective model and is used to select the most suitable genotype among genotypes in different environments. Using the SIIG method, drought tolerance indexes, different stability parameters or different traits can be determined as a single index, and the selection of superior genotypes is made more reliable and accurate.
Abdollah Youssefi
Abstract
Introduction Drought stress as the most extending abiotic stress has critical role on seed yield of canola in the dried and semidried regions of the world. Also, Climate changes affected canola production especially in Iran which had more fluctuant precipitation during spring. All growing and physiological ...
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Introduction Drought stress as the most extending abiotic stress has critical role on seed yield of canola in the dried and semidried regions of the world. Also, Climate changes affected canola production especially in Iran which had more fluctuant precipitation during spring. All growing and physiological aspects of canola plant is adversely affected by reduction of rainfall and increasing temperature milieu so that yield descend. There are many reports which announced vast genetic diversity among different species of canola in response to drought stress and results show that B. juncea had higher seed yield in drought stress condition than B. napus andB. rapa. Many traits and criteria are recommended for screening desired genotypes on the basis: 1) approved their role on drought resistance and yield, 2) comfortable measurement and suitable emergence in life cycle, 3) high heritability and 4) low time and expense for about 8 to 10 percent improvement at dried conditions. Effectiveness of used traits and criteria were investigated by many researchers and they reported that GMP, MP and STI are better than others due to their higher correlation coefficients with seed yield. Materials and Methods In order to study drought tolerance indices of 9 cultivars from 3 species of Brassica genous (B.napus, B. rapa, B. juncea), an experiment at 2 conditions including: terminal growth drought stress and control in 3 years, 2008-2009, 2009-2010 and 2010-2011, was conducted in the form of RCBD with 3 replicates in agricultural and natural research center of Khorassan-e razavi, Iran. Drought stress in terminal growth drought condition was applied by the initiation of reproductive growth after winter low temperatures on the basis of 110 mm evaporation from Class A pan in stress condition and 60 mm evaporation in control condition. Seed yield was measured on the basis of two middle rows after removing of marginal effect and drought resistance indices for each year calculated. Results and Discussion Combined analysis showed that effect of year on seed yield was significant and the highest seed yield (3025.8 kg/ha) obtained at the 1st year of experiment due to higher precipitation and lower temperature during terminal growth and prolonging of growth duration for 25 -34 days in comparing with 2nd and 3rd years. Also, means comparison of seed yield for 3 years showed that canola seed yield at non-stress condition was 2527.7kg/ha and 2049.28kg/ha at stress conditions averagely. Different cultivars showed significant dissimilar responses of seed yield at drought stress conditions with unequal precipitation in three years of experiments. Hyola401, Hyola 330 from B.napus species produced the highest seed yield either in drought stress or control conditions. Bp.18 and Landrace cultivars from B. juncea species had the lowest seed yield equal to 1469.8 and 1581.9 kg/ha, respectively. Drought resistance indices; MP, GMP, and STI showed maximum correlation with seed yield in both condition (drought stress and control). Conclusion Successful genotypes in restricted irrigation treatment had mainly higher potential yield than others and so this character is suggested for the first step of genotype screening. These genotypes will be introduced if they had also rational yield in limited water condition. This screening strategy can be authorized using STI, MP and GMP indices but using of stability indices such as YSI and YR mislead us for proper selection to have prosperous cultivars for years with high spring rainfall which happen unpredictably due to climatic variation at recent years. Totally, Hayola 401 and Hayola 303 are recommended according to their long term average yield in three years of experiment at both conditions and MP, GMP and STI criteria.
Mahmood Bahador; Mahmood Reza Tadayon; Mohammad Rafie-alhoseini; Mohammad Hasan Salehi
Abstract
Introduction Hemp is an old crop that used in oil extraction and textile. This plant has several medicinal characteristics. Drought stress is the most important environmental stresses in the world and a third of the arable land in the world is suffering from a shortage of water for agriculture. One of ...
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Introduction Hemp is an old crop that used in oil extraction and textile. This plant has several medicinal characteristics. Drought stress is the most important environmental stresses in the world and a third of the arable land in the world is suffering from a shortage of water for agriculture. One of the ways to deal with drought stress, use the tolerant plants and application of water preservative materials in the soil. Zeolite, because of having high cation exchange and the potential of resiliency, is use to improve drought stress conditions. Some researchers have shown significant effects of zeolite on physiological traits and grain yield of different crops in many experiments. Materials and methods To evaluate the effects of drought stress and zeolite on physiological characteristics and grain yield of hemp, an experiment was conducted in a randomized completely block design with three replications at the research farm of Shahrekord university in 2014. The main factor including irrigation in four levels (100, 80, 60 and 40% of water requirement) and the sub factor was zeolite at three levels (0, 5 and 10 t/ha). Density of hemp Seeds were 30 plants per square meter. The penman-monteith method by multiplying the crop coefficient (Kc) at different growth stages, was applied to calculate the plant daily evapotranspiration. Irrigation was done when the soil moisture in control treatment was reached to 50% field capacity. Also, volumetric flow meters were used to irrigation of other treatments (80, 60 and 40% of water requirement). Irrigation treatments was applied with opening the fourth of hemp leaf (1008 code in the growth stages of Cannabis sativa) and was continued until maturity and harvest. The latest of fully expanded leaf in flowering stage was used to calculate the leaf relative water content (RWC) and electrolyte leakage (EL). Analysis of data and the comparison of means was performed by SAS statistical software and the least significant difference (LSD) at 5 levels percent, respectively. Results and discussion Results indicated that the interaction between zeolite and drought stress, except canopy temperature, were significant on all of traits. Also, the results showed that 100% water requirement and 10 ton zeolite per hectare was highest in grain yield, leaf area index and relative water content, while the treatment of 40% water requirement and 0 ton zeolite per hectare, had the highest percentage of electrolyte leakage from leaf. The researchers stated that the reduction of leaf area under drought stress related to reducing in cell elongation and also, was due to aging and dropping of leaves. Leaf weight in 100% water requirement and 5 ton zeolite per hectare was 24.31% more than the treatment of severe stress. Since the initial reaction of the plant to reduce water, close the stomata to prevent water loss, plant with closing the stomata on the leaf cells, prevented of dehydration in other organs. This maybe increasing leaf temperature. It may also reflection of infrared energy from the leaves, especially during the midday, take the canopy temperature higher than while the water requirement was supplied. Also, the direct relationship between loss of canopy temperature and yield under drought conditions were reported by researchers. Considering the significant positive correlation between grain yield and leaf weight in this experiment, it can be guessed that excellence in traits such as leaf weight, especially in the oil-protein plants such as hemp, helped the plant in absorption of higher amount of light, carbon dioxide and thus reached higher yield. Severe drought stress maybe take inefficiencies in the cell membrane leaves and followed by it, increase membrane permeability and electrolyte content. Also, it’s maybe that the zeolite, due to keep the water in the hemp roots environment, by blocking the signals of lack of moisture in the root, thus reduces the destruction of cell membranes and ultimately reduce electrolyte leakage in the plant leaf cells. According to the results, the researchers also showed that the highest rate of electrolyte leakage from leaf cell membrane occurred at the lowest level of irrigation. Severe drought stress may lead to the closure of the stomata and then disrupt to absorption of carbon dioxide and dry matter production. Other studies have shown a significant positive effect on grain yield, because the ability of zeolite to hold the amount of more water in the soil. It seems that by reducing the moisture content, the role of zeolite in maintaining and easier transfer of moisture in the rhizosphere was featured. Conclusion Study of the evaluated traits showed that mineral moisture preservatives such as zeolite, had a significant role under lack of moisture condition. For example, application of zeolite under 40% moisture requirement were equals in leaf area index with no application of zeolite under 60% water requirement. In other words, with the use of zeolite, there was the possibility of producing grain yield and leaf area under use less water. Also, due to the significant positive correlation between leaf area index with leaf weight, application of zeolite under drought stress in hemp that increases yield and decreases destructive effects of drought stress such as electrolyte leakage and increasing in canopy temperature, therefore, it can be considered as a positive and reasonable result.
Arezo Mir Mozaffari Roudsari; Mehrdad Yarnia; Hadi Asadi Rahmani; Mahmood Toorchi
Abstract
Introduction This study was aimed to study effects of different bacterial strains on proline, chlorophyll and carbohydrate content under water shortage conditions in the field. Materials and methods A split plot experiment was used based on a randomized complete design in three replicates, with stress ...
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Introduction This study was aimed to study effects of different bacterial strains on proline, chlorophyll and carbohydrate content under water shortage conditions in the field. Materials and methods A split plot experiment was used based on a randomized complete design in three replicates, with stress in three levels of 40, 80 and 120 mm evaporation from pan and nine different bacterial strains as the main factor and the sub-factor, respectively. Results and Discussion The results showed that application of different bacterial strains and stress influenced the quantity of soluble carbohydrate in the leaves and proline. The highest amount of carbohydrate was obtained from seed inoculation of pseudomonas 169 along with 120 mm evaporation from the pan. Highest antioxidan properties by 89 mg/ml obtained in Azospirillium off and irrigation after 120 mm evaporation from the pan and lowest observed by 15.3 mg/ml in no bacterial treatment and irrigation after 40 mm evaporation from the pan. Also highest essential oil yield by 4 gr observed in herbasilus and 120 mm evaporation from the pan and lowest observed in Pseudomonas 168 and 40 mm evaporation from the pan by 0.85 gr. In this investigation in low and high grought stress using bacterial strains increased prolin and carbohydrate production than control. So using azeto 5 and azospirillium 21 in moderate drought and azeto 5 and herbasillus in sever drought stress can increase essential oil yield. These results provide enough evidence as to application of biological fertilizers brings about enhancements to the quality and quantity of dill. This could increase the plant oil yield under water shortage is and moderate conditions compared to the control. Conclusions The use of appropriate strains of bacteria such as Azatobacter5 and Azospirllium 21 can in condition of moderate and Azatobacter 5, pseudomonas 169 under stress condition, in medicinal plant to increase oil production.
Mahdi Ebrahimi; Gholam Reza Zamani; Zohreh Alizadeh
Abstract
Introduction Insufficient-water induced stress, causes morphological, physiological and biochemical changes in plants and has the potential to reduce leaf area, height and dry weight and cause stomatal closure, chlorophyll and photosynthesis reduction, amino acids accumulation, enzyme (Hassani and Omid ...
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Introduction Insufficient-water induced stress, causes morphological, physiological and biochemical changes in plants and has the potential to reduce leaf area, height and dry weight and cause stomatal closure, chlorophyll and photosynthesis reduction, amino acids accumulation, enzyme (Hassani and Omid Beighi, 2002) and protein destruction and changes the biosynthesis of the proteins (Jiang and Huang, 2000). Despite there are extensive studies on the effects of environmental stresses on the growth and yield of crops, there is very few information about medicinal herbs responses to these stresses (Amiri Deh Ahmadi et al., 2014). While water stress decreases growth of some medicinal plants such as Hypericum brasiliense (Nacif de Abreu and Mazzafera, 2005) and Bupleurum chinense (Zhu et al., 2009), many studies have shown that drought enhances the amount of secondary metabolites in wide veriety of plant species, such as Rehmannia glutinosa (Chung et al., 2006). Conversely drought caused a significant reduction in all growth parameters and essential oil yield and percentage in some medicinal plants such as peppermint (Mentha piperita L.) (Khorasaninejad et al., 2011).Considering the importance of the medicinal plant pot marigold (Calendula officinalis L.) in some industries such as pharmaceutical industry (Bousselsela et al., 2012), drought stress effects on flower yield and some quality-related traits of two marigold types was studied. Materials and methods Effect of drought stress on quantity and quality of harvested flowers of pot marigold was studied, using a complete block design as split plot with four replications in faculty of agriculture, Birjnand University, in 2015. Two factors including drought stress with three levels consisting of watering as 75, 50 and 25 percent of the soil field capacity (non-stressed, moderate and severe stress, respectively) and plant type (medicinal and ornamental type) were considered. Flowers were harvested and oven dried, 22 times during plant growth period. Logistic and linear models were compared using SAS software to choose the best model describing the rate of cumulative flower yield changes during growing season of pot marigold. Plant dry weight was the average dried weight of three randomized chosen plants at the end of growing season. Aluminum chloride colorimetric method with some modifications was used for flavonoid content determination (Yi et al., 2007). Essential oil of fresh flowers was extracted using Clevenger apparatus. As the essential oil content of pot marigold was very low, diethyl ether solvent was used to favor the extraction procedure. Results and discussion Evaluation of flower yield during the growth period (22 harvests) showed that this trait was significantly reduced by drought stress. The trend of cumulative flower yield was better described using non-linear logistic model compared with linear one. Comparing parameters of logistic model revealed that in non-stressed level flower yield increasing per plant was 0.059 g.day-1 that was approximately 69% higher than severe stress level (0.035 g.day-1). The highest and lowest cumulative flower yield were recorded in non-stressed (6.86 g.plant-1) and severe stress (3.46 g.plant-1) treatments, respectively. In addition, two marigold types were not significantly different in terms of flower production during the whole growth period. Under drought stress conditions, cell elongation in higher plants is inhibited by reduced turgor pressure. Reduced water uptake results in a decrease in tissue water contents and turgor is lost. Likewise, drought stress also trims down the photoassimilation and metabolites required for cell division (Farooq et al., 2009). As a consequence, impaired mitosis, cell elongation and expansion result in reduced growth (Kaya et al., 2006). In addition, reduced leaf size under drought stress leads to reduced light trapping capacity and as a result, total photosynthesis declines (Hsiao, 1973). The significant correlation between flower yield and plant dry weight (0.51**) indicates that reduced flower yield is a consequence of impaired dry weight under water deficit condition. Measured flavonoid content of flowers was primarily increased with increasing drought stress intensity from non-stressed (25.14 mg rutin equivalent.g-1 extract) to moderate stress (38.97 mg rutin equivalent.g-1 extract) level, however it was considerably decreased afterwards and reached the lowest amount (22.96 mg rutin equivalent.g-1 extract) at severe stress level. Increased flavonoid content at moderate stress level could be attributed to antioxidant function of these compounds (Franco et al., 2008). Circumstances, in which antioxidant enzymes are inactivated, stimulate biosynthesis of flavonoids. This indicates that flavonoids could act as a secondary antioxidant system for scavenging ROSs in plants under prolonged drought stress (Fini et al., 2011). Reduced flavonoid content at higher levels of drought however could be attributed to reduced activity of enzymes involved in flavonoid biosynthesis (Yang et al., 2007). Medicinal type of pot marigold showed a higher potential of flavonoid production. Flavonoid content of medicinal type of pot marigold was approximately 28% higher than ornamental type. Increasing drought stress also decreased the essential oil of flowers, so that the essential oil from 0. 120 in non-stressed level reduced to 0.062 mg. g-1 fresh flower in severe stress level. Observed decline in flower essential oil of pot marigold might be a result of disturbed photosynthesis and carbohydrate production and suppressed growth of stressed plants (Flexas and Medrano, 2002). However flowers of two marigold types had the same content of essential oil. Conclusion Cumulative flower yield of pot marigold as described by logistic model, was significantly reduced by water deficit, where the highest and lowest cumulative flower yield belonged to non-stressed and severe stress treatments, respectively. Flavonoid content was primarily increased and then decreased with increasing drought stress intensity. Increasing drought stress also decreased the essential oil of flowers, so that the essential oil in non-stressed treatment was approximately twofold higher compared with severe stress level.
khadijeh Ahmadi; Heshmat Omidi
Abstract
Introduction: With the advancement of science and the world's attention to the harmful effects of chemicals and synthetic materials, world again turned to the use of herbal products, so it is said twenty-first century, a century medicinal plants (Amanzadeh et al., 2011).Lallemantia royleana is a member ...
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Introduction: With the advancement of science and the world's attention to the harmful effects of chemicals and synthetic materials, world again turned to the use of herbal products, so it is said twenty-first century, a century medicinal plants (Amanzadeh et al., 2011).Lallemantia royleana is a member of Lamiaceae family. This family is one of the largest and most distinctive flowering plants (Zargari, 1980).Balangu seed is a good source of polysaccharides, fibre, oil and protein and has some medicinal, nutritional and human health properties (Naghibi et al. 2005; Razavi and Karazhiyan 2009). Drought is one of the major abiotic stresses that severely affect and reduce the yield and productivity of food crops worldwide up to 70% (Akram et al., 2013). The response of plants to drought stress is complex and involves changes in their morphology, physiology and metabolism (Sairam and Srivastava, 2001). Therefore, the objective of this research was to study evaluate the effect of drought stressthe quantity and quality of medicinalplant Bulangu population. Materials and methods: In the research experimental field of medicinal plants the Shahed University, during the 2014-2015 cropping season. This experiment was a split plot arrangement based on randomized complete block design (RCBD) with three replications. Three drought stress levels which include -3.5, -6.5, and -9.5 atm of soil water potential as the main factor levels, while five Bulangu population which include Esfahann3, Esfahann5, Esfahann6, Esfahann7 and Kordestan were arranged to sub plots. The site is located at latitude of 35°34´E, longitude 51°8´N, with an altitude of 1190 m above the sea level and its precipitation rate was 216 mm throughout the experimental period.Studied traits were determined according to the following protocols: Soluble sugars (Paquin and lechasseur, 1979), Mucilage percentage (Ghasemi Dehkordi, 2002), Inflation factor (Asgharpour and Rezvani Moghaddam, 2002), and Oil yield (Rasti et al., 2012). The RWC (relative water content) was determined according to Levitt 1990. All calculations were performed using the SAS software, version 9.1 and means were compared using Duncan’s range test at P=0.05. Results and discussion: Climate change is causing more frequent and intense periods of drought as overall rainfall levels decline. Dry areas cover more than 40% of the world’s land surface and are home to 2.5 billion people; one-third of the global population. Drought is currently one of the main constraints that prevent crop plants from expressing their full genetic potential. Drought had a significant effect on grain yield, biological yield, harvest index, soluble sugars, mucilage percentage, Inflation factor, RWC (relative water content) and oil yield. Drought was no significant effect on oil percentage.The results of this study demonstrate that increased drought reduced grain yield. Crop yield response to water efficiency in different stages of plant growth and water use throughout the growing season (Igbadun et al., 2006). The E3 population with the highest grain yield of (312.77 kg/ha) and oil yield of (86.7 kg/ha) in moisture potential -9.5 atm.Drought reduces the amount of soluble sugars. This results compatiblity with the results Abbaszadeh et al. (2007) in (Melissa officinalis).The effects of the interaction of E5 and E3 populations in the highest and lowest mucilage percentage mild stress into account. According to the study looks population Esfahan3, is to drought stress resistant population. Conclusions: It can be generally concluded that, drought stress atmosphere -9.5 atm decreases the quantitative and qualitative characteristics of medicinalplant Bulangu population. The Esfahan3 population has the highest grain yield and oil yield. According to the study looks population Esfahan3, is to drought stress resistant population. Results comparisons of traits in populations Balangu average suggests that most of these changes may be due to their genotype.
Mohammad Aghababaeian Najafabadi; Mojgan Sepehri
Abstract
Salt stress is the most prevalent environmental stresses limiting growth and yield of plants which has threatened crop production especially in arid and semi-arid regions of the world. Therefore, improving salinity tolerance in crop plants to grow in soils containing high amounts of soluble salts is ...
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Salt stress is the most prevalent environmental stresses limiting growth and yield of plants which has threatened crop production especially in arid and semi-arid regions of the world. Therefore, improving salinity tolerance in crop plants to grow in soils containing high amounts of soluble salts is very important regards to decrease in crop production. Soil beneficial microorganisms including bacteria and endophytic fungi have important role in improving host plants adaption to abiotic (drought, salinity, heavy metals …) and biotic (pests and plant pathogens environmental stresses. Piriformospora indica is one of the important endophytic fungi which not only promotes plant growth, but also increases plant tolerance to environmental stresses including salinity. The main purpose of this research is to investigate the effect of P. indica on increasing salinity tolerance of corn. Materials and methods A greenhouse experiment in a completely randomized design with two factors including salinity (0, 100, 300 mM NaCl) and fungal inoculation (inoculation and non-inoculation) was conducted in a 2/1 (v/v) mixture of sterile sand and perlite. Salt stress was treated after 10 days of planting and continued for 8 weeks. After the plants finish their vegetative stage, root sampling was performed and percentage root colonization by the fungus and total biomass yield, that is, root dry weight and shoot fresh and dry weights were measured. Also, the concentration of some nutrients such as sodium (Na), potassium (K) and phosphorus (P) was determined. Results and discussion Microscopic investigations of inoculated roots with P. indica indicating high potential of this fungus to colonize roots of the studied plant, so that large amount of external hyphae from germinating spore was seen at the outer surface of the roots and the root cortex. The obtained results indicate that in sever salinity stress (300 mM NaCl), the shoot dry weight of inoculated plants with P. indica was approximately 90% higher than the non-inoculated control plants. Phosphorous content of the shoot part of plants with fungal symbiosis at the levels of 0 and 100 mM of NaCl was 8.5% and 12% greater than the control plants, respectively. Sodium content in the leaf of inoculated plants with P. indica was lower than the controls. Unlike sodium, increasing salinity resulted in decrease potassium content in the root. Calculating K+/Na+ shows a decrease of this ratio in all treatments except shoot part of inoculated plants with the fungus. P. indica significantly by increasing the absorption of water by plant cells which ultimately results in increased plant water potential, significantly inhibits deleterious effects of salinity on plant. In addition, through inducing the uptake of the necessary nutrients for plant and synthesizing plant growth promoting compounds, this fungus improves the morphological characteristics of plant such as fresh and dry weights of root and shoots as well as plant yield. Excess absorption of sodium ion by plant in saline environment increases the amount of this ion in plant root and shoots which ultimately disturb cell enzymatic and plasma membrane systems. So, low sodium concentration in the leaves of inoculated plants with P. indica and high amount of this ion in the roots in compare to the control plants shows that prevention of excess sodium movement to the leaves and its accumulation in the root is probably one of the possible mechanisms for plant growth promotion of this fungus. Also, high K+/Na+ ratio in the shoot of inoculated plants with P. indica in compare to the controls at different levels of stress demonstrate the tolerance of these plants to salinity. Conclusions This research revealed the positive effects of Piriformospora indica as an endophytic fungus on promoting plant growth. In addition to beneficial effects of P. indica as a growth-promoting fungus (GPF), P. indica inoculations ultimately lead to increase barley resistance to salt stress.
Kami Kaboosi; Mohammad Shamyati
Abstract
Introduction There is an increasing pressure to apply low quality brackish water for irrigation in the arid and semi- arid areas of the world. Consequently, there is a demand to identify the salt tolerant of conventional crops and varieties. Materials and methods In order to investigate the effect ...
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Introduction There is an increasing pressure to apply low quality brackish water for irrigation in the arid and semi- arid areas of the world. Consequently, there is a demand to identify the salt tolerant of conventional crops and varieties. Materials and methods In order to investigate the effect of four salinity levels of irrigation water (including 1.15, 4, 7 and 10 dS.m-1) on phonology, morphology, yield component, yield, oil and water use efficiency of different cultivar of canola (Hyola 4815, 308 and 401 and RGS 003), an experiment was designed as factorial based on complete randomized blocks with 3 replications. Pot experiment was conducted in a semi- controlled environment. In order to avoid toxic effects of some ions, different levels of salinity were prepared with equal weight ratios composition of different salts. Results and discussion The results of analysis of variance showed that the canola cultivar significantly affected days to flowering, days to maturity, plant height, height of the first secondary branch, height of the first silique, stem diameter, secondary branch number, silique length, silique number per plant, seed number per silique, 1000 seed weight and harvest index. Means comparison test indicated that the RGS cultivar had the highest value in aspect of days to flowering, plant height, height of the first secondary branch, height of the first silique and stem diameter. Given the significant positive correlation (r=0.58**) between the number of days to flowering and days to maturity, cultivars differences from the pattern of change of these traits were similar. The RGS and Hyola 401 cultivars had an average of 2.25 secondary branches less than other cultivars and this difference was significant. Significant negative correlation between number of secondary branches and days to flowering (r=-0.51**) showed that shortening the length of vegetative growth resulted to reduce the number of secondary branches. The RGS and Hyola 4815 cultivars had the highest and lowest stem diameter with 0.629 and 0.381 cm, respectively. Means comparison showed that cultivars differences of silique length and seed number per silique because of positive correlation between them(r=0.60**) were followed the same trend. Highest value of silique length, seed number per silique and 1000 seed weight were found in Hyola 401 cultivar. However, maximum values of silique number per plant, seed yield, biological yield, harvest index and seed water use efficiency have been seen in Hyola 308 cultivar. Regarding to positive correlation between seed yield with number of silique per plant and number of secondary branches on the one hand and remarkable advantage of Hyola 308 compared with other cultivars in aspect of these traits on the other hands, significant superiority of seed yield of Hyola 308 can be attributed to its more ability for production of silique and secondary branch. On the base of analysis of variance results, the salinity effect was significant on days to flowering, plant height, the height of the first secondary branch, height of the first silique and seed number per silique. Increase of salinity from 1.15 up to 10 dS.m-1 led to significant increase of days to flowering (6 days) in all cultivars and significant reduction of days to maturity in all cultivars except RGS. Results of means comparison showed that increase of irrigation water salinity from 7 up to 10 dS.m-1 led to significant reduction of plant height traits. The salinity significantly decreased number of seeds per silique, seed yield, biological yield, harvest index and oil yield. However, reduction of stem diameter and number of silique per plant and increase of 1000 seed weight and number of secondary branches were not significant. Increasing the salinity from 1.15 (control treatment) up to 10 dS.m-1 resulted in significant reduction of seed and oil water use efficiencies about 50 and 25 gr.m-3, respectively. Interaction effect between salinity and cultivar was significant on number of days to maturity, silique length, oil yield and oil water use efficiency that shows responsibility of rapeseed cultivars to different levels of salinity in terms of these traits is different. Accordingly, while increasing salinity resulted reduction in number of days to maturity in different varieties of Hyola, it was increased in the RGS cultivar. Hyola 4815 and 401 cultivars had lowest oil yield and oil water use efficiency in low (1.15 and 4 dS.m-1) and high (7 and 10 dS.m-1) water salinity levels, respectively. However, highest values of oil yield and oil water use efficiency observed in Hyola 308 cultivar in water salinity 4 dS.m-1. Conclusion Results showed that due to the lack of interaction between salinity and cultivar in respect of many traits, the tolerance of different varieties to salinity was evaluated the same. Also, among the four studied cultivars, the Hyola 308 cultivar is recommended.
Hamdollah Eskandari; Ashraf Alizadeh-Amraie
Abstract
Introduction Heavy metals, as one of the most important factors contaminating natural environments and agricultural ecosystems, are found in almost all industrial regions. Toxic effect of high concentration of heavy metals is also observed in plants. One of the specific characteristic of heavy metals ...
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Introduction Heavy metals, as one of the most important factors contaminating natural environments and agricultural ecosystems, are found in almost all industrial regions. Toxic effect of high concentration of heavy metals is also observed in plants. One of the specific characteristic of heavy metals which has high influence in occurrence of toxicity of heavy metals is their bioaccumulation. Heavy metals are not biologically inseparable and decomposable and remain in environment which finally threaten human health. Therefore, removing, or at least, reducing their concentration in agronomical systems is closely related to human health. Cadmium is a heavy metal which is an unnecessary element for plants and enter agronomical systems through pesticides usage. However, cadmium is easily absorbed by plant roots and its toxicity is 20 times more than that of other heavy metals. There are chemical, physical and biological methods for removal of heavy metals from agronomical soils. Phytoremediation is a low cost and environmental compatible method for heavy metal removal from soils. This research was aimed to compare the ability of wheat, clover and rapeseed for removal of cadmium from agronomical soils to achieve the goal of reduction of heavy metal for incoming crop in rotation. Materials and methods The current research was conductedas3×3 factorial experiment based on randomized complete block design with three replications. The first factor was plant type including wheat, clover and rapeseed and the second factor was heavy metal concentrations including 0.0, 50 and 100 mg kg-1 soil. Soil samples were contaminated with cadmium concentrations of 0.0, 50.0 and 100 mg per kg soil. Experimental plots (with height and diameter of 40 cm) were filled with 10 kg contaminated soils. Four weeks after planting, all plants parts (including root and shoot) were harvested and oven dried at 75°C for 72 hours. Finally, cadmium concentration was determined in all plants. Results and discussion The highest cadmium uptake was observed in wheat under the concentration of 50 and 100 mg kg-1 soil. Increasing cadmium concentration from 50 to 100 mg kg-1 soil had not significant effect on the ability of wheat, clover and rapeseed for cadmium uptake from soil. Plants with high biomass are capable for more heavy metals uptake which is line with the findings of this research where wheat with higher biomass removed more cadmium from soil in comparison with clover and rapeseed. However, nonsignificant difference between clover and rapeseed for cadmium uptake was not compatible with this opinion where rapeseed produced higher biomass. Although different physical, chemical and biological methods are used for removal of heavy metals from soils, phytoremediation has the highest effect for removal of cadmium from soils. Conclusion The current research confirmed the results of other experiments about the ability of phytoremediation for removal of cadmium from soil. Furthermore, the results revealed that wheat, in addition to its nutritional value, has a high ability for reduction of cadmium from contaminated soils and can be considered as a good crop in crop rotation programs.
Volume 10, Issue 2 , July 2017, Pages 349-349
