Mohammad Kafi
Ahmad Nezami; Surur Khoramdel; Mahdi Nassiri-Mahallati; Ali Asghar Mohammad-Abadi
Abstract
In order to study the effects of fall planting on yield and yield components of five cumin (Cuminum cyminum L.) landraces a field trial was arranged in a randomized complete block design as a split-plot with three replications during 2006-07 growing season at the Agricultural Research Station of Ferdowsi ...
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In order to study the effects of fall planting on yield and yield components of five cumin (Cuminum cyminum L.) landraces a field trial was arranged in a randomized complete block design as a split-plot with three replications during 2006-07 growing season at the Agricultural Research Station of Ferdowsi University of Mashhad. Three fall planting dates (17 Oct. (first), 16 Nov. (second) and 16 Dec. (third)) and five cumin landraces (Torbat Heydarieh, Khaf, Sabzevar, Ghaen and Ghoochan) were allocated to main and sub plots, respectively. Results showed that there were significant differences between planting dates, cumin landraces and their interactions for winter survival percentage, umbel per plant, seeds per umbel, 1000-seed weight, seed yield, biological yield and harvest index (HI). There was a reduction on umbel per- plant and seed per- umbel due to delay in planting date from 17 Oct. to 16 Dec. The highest winter survival percentage, seed yield and biological yield and also HI were achieved on the third planting date. Also, the maximum and minimum seed yield were observed in Ghaen in the third planting date and Khaf in the second planting date with 62.5 gm-2 and 12.1 gm-2, respectively. According to these results and for the deployment of cumin fall planting in other locations of province, further studies are recommended.
Hamid Reza Roosta; AbdolReza Sajjadinia
Abstract
Cold stress causes great yield reduction in greenhouse crops. In order to study the damage of cold stress in some greenhouse crops, a factorial experiment based on CRD was conducted with two factors including temperature in two levels (4 and 21 ºC) and plant species in four levels (green basil, ...
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Cold stress causes great yield reduction in greenhouse crops. In order to study the damage of cold stress in some greenhouse crops, a factorial experiment based on CRD was conducted with two factors including temperature in two levels (4 and 21 ºC) and plant species in four levels (green basil, violet basil, tomato and lettuce) with 3 replications. To apply the cold stress, these plants were placed under 4°C and dark condition for 12 hrs. The results showed that minimal chlorophyll fluorescence of basil plants was significantly higher in control plants compared to the cold-stressed ones, whereas in lettuce it was significantly higher in cold-stressed plants. In this experiment, it was also observed that maximal fluorescence (Fm), variable fluorescence (Fv) and maximum quantum efficiency of photosystem II (Fv/Fm) of green basil, violet basil and tomato plants were significantly lower under cold stress compared to the control. In contrast, these parameters were increased by cold stress in lettuce. These findings confirm the resistance of lettuce to cold stress and stimulating this plant to increase the maximum quantum efficiency of photosystem II under low temperature conditions.
Shamideh Shabanzadeh; Mohammad Galavi
Abstract
The application of micronutrients can improve the growth and yield of crops under stress conditions. In order to investigate the effect of micronutrient foliar application and irrigation regimes on black cumin, a field experiment carried out in Agricultural Research Center of Bojnord, Iran, in 2009. ...
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The application of micronutrients can improve the growth and yield of crops under stress conditions. In order to investigate the effect of micronutrient foliar application and irrigation regimes on black cumin, a field experiment carried out in Agricultural Research Center of Bojnord, Iran, in 2009. The experiment was conducted as split plots in a randomized complete block design with three replications. Irrigation intervals of7, 14 and 21 days were considered as main factors and five micronutrient foliar application steps including: control, B, Zn and Fe in 2, 3 and 4 PPT, respectively as well as a mixture of three above mentioned elements were considered as sub plots. Results showed that the irrigation regimes significantly affected plant height, subsidiary branches, capsule number per plant, number of seeds per plant and capsule, 1000 grain weight, grain and biological yield and harvest index, so that increasing the irrigation period decreased all of the above mentioned traits. The maximum grain yield obtained by seven-day irrigation regime. Moreover, foliar application of micronutrients significantly affected plant height, capsule number per plant, number of seeds per plant and capsule, grain and biological yield and harvest index. The differences amongst micronutrients spraying treatments and the control were significant for all above mentioned traits. Foliar application with the mixture of three micronutrients resulted in the greatest grain yield.
Hadi Pirasteh Anosheh; Yahya Emam
Abstract
Application of plant growth regulators (PGRs) could be one of the methods to compensate for the harmful effects of drought stress, as the most important factor limiting wheat yield. To examine the effect of two PGRs; cycocel (CCC) and salicylic acid (SA) on grain yield and its components of a bread (Roshan) ...
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Application of plant growth regulators (PGRs) could be one of the methods to compensate for the harmful effects of drought stress, as the most important factor limiting wheat yield. To examine the effect of two PGRs; cycocel (CCC) and salicylic acid (SA) on grain yield and its components of a bread (Roshan) and a durum (Yavarous) wheat under different water regimes [normal (as control), moderate and severe drought], field and greenhouse experiments were carried out at the Research Field and Greenhouse of College of Agriculture, Shiraz University during 2009-2010 growing season. Field and greenhouse experiments were organized as a split factorial based on randomized complete block design and completely randomized design, respectively. Results showed that drought stress caused remarkable reductions in ear length, grain number per spikelet, grain and spikelet number per ear, grain yield, biological yield and harvest index. The highest and lowest effects of drought stress were observed in biological yield and 1000- grain weight, respectively. PGRs increased ear length, grain number per spikelet, grain and spikelet number per ear, 1000- grain weight as well as the grain yield. SA and CCC application was associated with enhancement and reduction in biological yield, respectively. Harvest index was increased in CCC treated plants. Responses of Roshan cultivar yield and its components to drought stress and both PGRs application were more than Yavarous. Also it appeared that Roshan cv. had more grain yield, and Yavarous had higher resistance to drought stress. Although drought stress caused reductions in most yield components of wheat, PGRs application could alleviate a part of these harmful effects. Therefore application of these PGRs, especially CCC, is recommended under drought stress conditions.
Ali Reza Sobhani; Hasan Hamidi
Abstract
In order to study the effect of water deficit and potassium fertilizer on the yield and water use efficiency (economic and biologic) a split block experiment based on RCBD was conducted with three replications using line-source sprinkler irrigation in Khorasan Razavi Agricultural and Natural Resources ...
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In order to study the effect of water deficit and potassium fertilizer on the yield and water use efficiency (economic and biologic) a split block experiment based on RCBD was conducted with three replications using line-source sprinkler irrigation in Khorasan Razavi Agricultural and Natural Resources Research Center. Potassium levels including 0, 90, 180, and 270 kg K2O ha-1 were considered as main plots. Water deficit levels including 0.75m (control), 3.75m (very light), 6.75m (light), 9.75m (severe deficit), and 12.75m (very severe deficit) from the line source were considered as sub plots. These factors were investigated in a special line-source statistical design with three replications (in right and left of line-source), so that the right or left direction of the line source was assigned as the sub-sub plots. Results showed increased tuber yield and biological yield of potato through application of potassium, whereas increasing the distance from the line source decreased these traits. Under very severe stress conditions (12.75m from the line source), the tuber yield was 80% and 62.67% lower than the control at the first and second year of the study, respectively. The highest economical water use efficiency (EWUE), biological water use efficiency (BWUE) and tuber yield resulted from 270 kg K2O ha-1. Interaction effects of potassium and water amounts on yield, EWUE and BWUE were significant in the second year. The greatest yield was obtained from 270 kg K2O ha-1 and control treatment (sufficient water) and the highest BWUE was observed using 270 kg K2O ha-1 and severe deficit.
Maryam Golabadi; Zahra Abbasi; Ahmad Reza Golparvar
Abstract
Drought stress as the most important abiotic stress has an important role in reducing crop production in arid and semi-arid regions of the world. The physiological traits related to drought stress are of utmost importance in this regard. In order to evaluate the effect of drought stress on physiological ...
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Drought stress as the most important abiotic stress has an important role in reducing crop production in arid and semi-arid regions of the world. The physiological traits related to drought stress are of utmost importance in this regard. In order to evaluate the effect of drought stress on physiological indices of bread wheat flag leaf, a split plot experiment was conducted based on randomized complete block design with three replications at the Faculty of Agriculture, Azad University of Khorasgan during 2008-2009 growing season. The three different irrigation conditions including normal irrigation, irrigation cease from 50% of head emergence to harvesting as well as irrigation cease from 50% of head emergence to harvesting with 30% increase in N fertilizer were assigned as the main plots and 7 genotypes of bread wheat were consisted as sub plots. The results of ANOVA showed that the physiological traits of relative water content, leaf water content, moisture retention capacity, cut leaves water retention, water loss ratio, as well as seed yield trait had significant differences under different environmental conditions. The amount of physiological traits under drought stress with extra N fertilizer was significantly greater than under drought stress without extra N fertilizer. In fact, extra N fertilizer increased plant tolerance to drought stress conditions through increasing the vegetative growth and leaf water content. Results showed that Pishtaz and Sepahan cultivars as well as line 11 which possessed the greatest grain yield, had the highest physiological traits and the lowest amount of water loss in different environments.
Elham Kolahian Hamedanizad; Hosseinali Ramshini; Mohammad Ghader Ghaderi; Mehdi Fazel Najafabadi
Abstract
In Iran where main part of precipitation takes place during winter and spring, wheat is dependent on water conserved in the sub soil especially at dryland farming systems. In order to identify the genotypes with suitable root system development at sub soil depths, an experiment was conducted with 63 ...
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In Iran where main part of precipitation takes place during winter and spring, wheat is dependent on water conserved in the sub soil especially at dryland farming systems. In order to identify the genotypes with suitable root system development at sub soil depths, an experiment was conducted with 63 bread wheat genotypes planted in PVC tubes under non stress and drought stress conditions. Under non-stress condition irrigation was conducted regularly, while under stress condition it was delayed until soil moisture was depleted to 30 percent of field capacity. After applying stress and at the end of growth season, root related traits in four depths (0-20, 20-40, 40-60 and 60-100 cm) along with morphological traits, yield and its components were measured. The results showed great variations among genotypes for all studied traits. Highly significant correlations were observed between total root weights and yield under stress conditions (r=0.58, p=0.01). Under these conditions, a unit increase in root dry weight resulted in a 0.24 g increase in grain yield of each plant. Separate correlation analysis for each depth showed that the effect of root dry weight on yield at the deepest depth was higher than other profiles (r=0.75, p=0.01). Under stress conditions, the effect of root weight on yield at 60-100 cm depth was positive and highly significant. Genotypes of Sardari, Sholeh, Naz and Inia were the best genotypes considering root dry weight at this profile with 0.44, 0.39, 0.37 and 0.37 g.plant-1, respectively.
Hamid Reza Bagheri; Mohammad Hosein Gharineh; Abdolmehdi Bakhshandeh; Javad Taei; Abdolmohammad Mehnatkesh; Bahram Andarzian
Abstract
Introduction Potato (Solanum tuberosum L.) is one of the most important crops that plays a major role in feeding the world. The growing demand for potato, as both a fresh and processed food, along with the increase in world population, mean that yield will have to be improved through some combination ...
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Introduction Potato (Solanum tuberosum L.) is one of the most important crops that plays a major role in feeding the world. The growing demand for potato, as both a fresh and processed food, along with the increase in world population, mean that yield will have to be improved through some combination of germplasm enhancement, better crop protection and more efficient and productive management of irrigation and fertilization (Haase et al., 2007). Researches have proved potato is sensitive to drought stress at all stages of growth, especially at tuber formation stage due to reduction of leaf area and photosynthesis (Fabeiro et al., 2001; Ayas, 2013; Shock et al., 2013). Abiotic stress factors, such as drought, have severe, adverse effects on potato growth and yield. In particular, a regular water supply is necessary to achieve a high quality yield (Ierna and Mauromicale, 2006). In comparison with other species, potato is very sensitive to water stress because of its shallow root system (Ayas, 2013). Water shortage during tuber differentiation can delay growth and reduce earliness, whereas during tuber growth and bulking can decrease tuber size and have a drastic effect on yield (Alva et al., 2012; Liu et al.; 2006; Ayas, 2013). For processing potato, a careful N and water management is required to ensure regular growth, high dry matter content and marketable tubers (Shock et al., 1998; Zhang et al., 2006; Shahnazari et al., 2007). So this research was done to evaluate effects of different levels of water deficit and nitrogen fertilizer on tuber yield, yield components and water use efficiency of potato crop in Chahar Mahal va Bakhtiari province, in Iran. Materials and methods In order to study the effects of different levels of water deficit and nitrogen fertilizer on tuber yield and other agronomic traits of potato crop (Boren variety), a split plot experiment based on randomized complete block design, conducted at Chahar Mahal va Bakhtiari Research Center of Agriculture and Natural Resources, in 2013. The levels of water deficit were S1, S2 and S3 (100, 75 and 50% of the water requirement of potato crop after emergence by the end of the growing season, respectively), as the main plots and nitrogen fertilizer treatments were N1, N2, N3 and N4 (100, 66, 33 percent of plant nitrogen requirement and without nitrogen consumption, respectively) as sub plots. Results and discussion In this experiment water deficit had decreasing effect on tubers dry matter percent but nitrogen changes had no distinct effect on this trait. By applying water deficit and decreased levels of nitrogen, the number of tubers per plant and the average tubers weight also fell. The greatest and the lowest number of tubers per plant were seen at S1 and S3 treatments (8.4 and 7.4 respectively). The maximum weight of tubers observed at full irrigation treatment (118 g) that had no significant difference with S2, but at treatment S3 (50% of the water requirement), tubers were produced lighter with an average weight of 86.6 grams. So it can be concluded, in this irrigation regime, the average weight of tubers is closer to weight of seed tuber class. Many studies have confirmed these findings (Fabeiro et al., 2001; Ayas and Korukcu, 2010; Ayas, 2013). The results showed that maximum tuber yield gained from S1 treatment (55.9 ton/ha) that had no significant difference with S2, but intensive drought stress (S3) produced minimum tuber yield (31.7 ton/ha). N1 and N2 treatments led to highest tuber yield but the lack of nitrogen (N4) caused the lowest tuber yield (38.7 ton/ha). Generally, in S2 and S3 drought stress levels, N2 produced maximum tuber yield. The reduction of tuber yield in S2 and S3 treatments within increment of nitrogen consumption (N1), caused the significant interaction between drought stress and nitrogen on tuber yield. Ierna and Mauromicale (2006) reported that water deficit stress as much as 50% of the water requirement, had increased stomatal resistance and caused the reduction of leaves photosynthesis, biomass, tuber growth and tuber yield. Demelash, 2013; Alva et al., 2012 and Ayas, 2013 studies also confirm the results of this Research. The second level of nitrogen (N2) in S3 treatments led to maximum, but S1N4 led to minimum water use efficiency (9.21 and 5.24 kg/m3 respectively). Liu et al. (2006) reported, by reducing the amount of irrigation volume, tuber yield decreases baut water use efficiency will increase.The stepwise regression analysis showed that the average tuber weight explains most changes of marketable tuber yield per plot. Conclusions Based on the results of the present study, since there is no statistical difference in tuber yield, between S1 and S2 irrigation regimes, it is recommended that for proper utilization of water resources and achieve economic yield, potato crop, produce with 6400 m3 water per hectare with irrigation at 7 days period. Results showed, at S2 irrigation regime, N2 Treatment (consumption of 270 kg Urea/ ha) had produced the highest yield, so S2N2 treatments is the best option for potato crop production.
Maryam Karimiyan; Fayaz Aghayari; Farzad Paknejad
Abstract
Introduction Many countries have used crop growth models to simulate crop response to environmental stress and various management methods in different decades (Mehraban, 2013). One of the goals of crop simulation models is to be used for crop yield prediction. Researchers have proposed and used various ...
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Introduction Many countries have used crop growth models to simulate crop response to environmental stress and various management methods in different decades (Mehraban, 2013). One of the goals of crop simulation models is to be used for crop yield prediction. Researchers have proposed and used various models so far, including: Crop Environment REsource Synthesis (CERES) (Jones and Kiniry, 1986), WOrldFOodSTudies (WOFOST) (Van Keulen and Wolf, 1986), Cropping Systems Simulation Model (CropSyst) (Stockle et al., 1984), etc. However, it should be noted that proposing such models requires the user to be highly skilled at calibration since there are lots of input variables measuring of which is a difficult task. Using some underlying functions, Cordery and Graham (1989) developed a model to simulate crop growth and water value in this process. The model, which in known as MEDIWY, was then calibrated for winter wheat under Bajgah field condition (Ziaei and Sepaskhah, 2003). Generally, using common data, the model which is measured in nearly all weather stations has the potential to properly estimate both growth indices and wheat grain yield under dry and irrigated farming. Its broader application requires doing more experiments in different weather conditions. Therefore, with regard to applicability of MEDIWY model, with at least input data, the present study is to evaluate this model by simulating wheat yield (Marvdasht cultivar) under different irrigation treatments in Karaj region. Materials and Methods The current research is conducted to study MEDIWY model in simulating wheat yield (Marvdasht Cultivar) under Karaj weather condition. In doing so, we used nine irrigation treatment data carried out in research farm of Islamic Azad University of Karaj during 2003-2004 crop year (Paknejad, 2005). Also, additional required information, such as meteorological data (amount of daily pan evaporation and rainfall) are obtained from Mahdasht weather station in Karaj region. Values concerning meteorological data (rainfall and pan evaporation) and irrigation are entered to this model as input variables. Considering that each of the irrigation treatments used in this study have a special irrigation regime and applied in different stages of growth, for more accurate calibration of MEDIWY model, irrigation treatments are divided to three groups based on level of drought stress so as to be able to calibrate each group separately. For the purpose of evaluating the model, several statistics evaluation methods are employed including: linear regression analysis of observed and simulated data and its comparison with 1:1 line method, Coefficient of Determination (R2), Root Mean Square Error (RMSE), Normalized Root Mean Square Error (NRMSE), and Model Efficiency (ME). Results and Discussion Results showed that after calibrating MEDIWY model for simulating wheat yield (Marvdasht cultivar) in Karaj region, the obtained values for RMSE, NRMSE, and ME were 265 Kg.ha-1, 5.7%, and 0.99, respectively, which represent appropriateness of statistical indices of calibrated part of the model. According to validation results, statistical indices of RMSE, NRMSE, and ME were 412 Kg.ha-1, 8.5%, and 0.99, respectively, which indicate that the calibrated MEDIWY model can simulate wheat yield values in Karaj region very well. According to findings of the current research, although MEDIWY requires less input data compared to other crop growth models, it has great potential and accuracy for simulating crop yield. Conclusions According to findings of the current research, although MEDIWY requires less input data compared to other crop growth models, it has great potential and accuracy for simulating crop yield.
Maryam Akbarpour; RamezanAli Khavari-Nejad; Ali Moumeni; Farzaneh Najafi
Abstract
Introduction Water scarcity causes rice yield loss more than 30% under drought stress at field conditions. Hence, employing drought tolerant cultivars in this condition is an effective way to overcome such a challenge. Therefore, in current research, we have used three Iranian rice cultivars named Amol3, ...
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Introduction Water scarcity causes rice yield loss more than 30% under drought stress at field conditions. Hence, employing drought tolerant cultivars in this condition is an effective way to overcome such a challenge. Therefore, in current research, we have used three Iranian rice cultivars named Amol3, Sang-tarom and Neda, which is originated from a cross between Amol3 and Sang-tarom, in order to investigate responses of the selected rice cultivars to drought stress. In this study, several important physiological characteristics were evaluated under drought stress during a growth period. Therefore, present study was aimed to achieve some information about mechanisms and responses to drought stress and to use them in identifying tolerant cultivars in drought stress situation as well as employ them in rice breeding program. Materials and Methods The rice seedlings of three genotypes were tested at greenhouse under three levels of water treatments as: control (FTSW=1.0, Fraction of Transpirable Soil Water), mild drought stress (FTSW=0.5) and severe drought stress (FTSW=0.2) in four replications in 28±2ºC in day and 25± 2º in night and in 14 L/10 D light period in a factorial arrangement of treatments in randomized complete block design in PVC pipes with 1-meter-long and 10 cm in diameter. The root length, stomatal aperture size, ABA content in leaves and wet and dry weights of panicles were measured as essential features in these cultivars in both drought stress levels and in control treatment. For data analysis SPSS and SAS software was applied. Results and discussion In this study, we found that in rice cultivar Neda, showed a significant reduction (P<0.05) in ABA level under mild and severe drought stress treatments, while rice cultivar Amol3 had a significant reduction in ABA level only at severe drought stress compared to control. We also observed a non-significant increasing trend in ABA level in response to drought stress levels in Sang-tarom cultivar. The amount of ABA reduction was higher in Neda compared to Amol3. In all three cultivars root growth was increased but in different way in drought stress treatments compared to control. Stomatal aperture size reduced significantly in Neda under severe drought stress, under both two drought stress levels in Amol3 compared to control. No significant difference was indicated in stomatal aperture size of Sang-tarom at both drought stress treatments compared to control. Differences in stomatal aperture size reduction were not significant among cultivars. Wet and dry weights of panicles were also affected by drought stress treatments in three cultivars. There was no significant reduction in wet and dry weights of panicles in Neda at mild drought stress level compared to control, but highly significant reduction was observed for two characteristics of wet and dry weights of panicles in Amol3 and Sang-tarom at both drought stress levels as compared to control treatment. In all three cultivars, decreasing of wet and dry weights of panicles was significant under severe drought stress compared to control. Conclusion In Neda, no significant reduction was observed in stomatal aperture size while the maximum dry and fresh weights of panicles was found in Neda under mild drought stress condition, which could be a remarkable sign among the cultivars in long-term drought stress. A total of 30% reduction was observed for grain yield of Neda while the yield loss for Amol3 and san-tarom were 58% and 50%, respectively. Reduction in ABA level in leaf, root length stimulation and stomatal aperture size regulation could be assigned to the behaviors in highly tolerant cultivars under drought stress condition. Neda showed more similar responses to Amol3, one of its parent, than to Sang-tarom regarding increasing in root length and reduction in ABA level in leaf in response to drought stress. A good correlation between root length and reduction in ABA level or redistribution of ABA in root for better hydraulic conductivity and also preventing ethylene action in drought stress that needs to be more studied.
Ali Mahrokh; Majid Nabipour; Habib Alah Roshanfekr; Rajab Choukan
Abstract
Introduction Drought is one of the major environmental conditions that adversely affect plant growth and crop yield. In the face of a global scarcity of water resources, water stress has already become a primary factor in limiting maize production worldwide. It’s because Phytohormones such as auxin ...
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Introduction Drought is one of the major environmental conditions that adversely affect plant growth and crop yield. In the face of a global scarcity of water resources, water stress has already become a primary factor in limiting maize production worldwide. It’s because Phytohormones such as auxin and cytokinin are reported to be involved in the regulation of plant response to the adverse effect of drought stress conditions. This study carried out in order to evaluate some physiological parameters response to auxin and cytokinin hormone alternation under drought stress condition on maize (cultivar KSC 704). Materials and Methods The experiment was carried out in three separately environments included non-drought stress environment (irrigation after soil moisture reached to 75% field capacity), drought stress in vegetative stage (irrigation after soil moisture reached to 50% field capacity in V4 to tasseling stage, but irrigation after soil moisture reached to 75% field capacity in pollination to physiological maturity stage) and drought stress in reproductive stage (irrigation after soil moisture reached to 75% field capacity in V4 to tasseling stage and irrigation after soil moisture reached to 50% field capacity in pollination to physiological maturity stage). cytokinin hormone in three levels (control, spraying in V5 –V6 and V8-V10 stages) and auxin hormone in three levels (control, spraying in silk emergence stage and 15 days after that) was laid out as a factorial design based on randomized complete block with three replications in each environment at Seed and Plant Improvement Institute (SPII), Karaj, Iran, in 2013. It was used Indole-3-butyric acid and N6-benzyladenin as auxin and cytokinin hormones respectively. Concentration of used auxin and cytokinin hormones were 10 and 50 mg per liter respectively. In this study some physiological parameters were measured including leaf area index, cell membrane stability, leaf chlorophyll content, stomata conductive, canopy temperature depression, photosynthesis quantum efficiency and leaf senesce. Results and Discussion The maximum leaf area index, stomata conductance and quantum efficiency of photosynthesis and the minimum canopy temperature were obtained with spraying cytokinin hormone in V8-V10 stage, and the maximum chlorophyll content index, quantum efficiency of photosynthesis and the delay in leaf senescence were obtained with spraying auxin hormone in silk emergence stage and the minimum stomata resistance and canopy temperature were obtained with spraying cytokinin hormone in 15 days after silk emergence stage. The interaction effect between drought stress and spraying hormone was significant on leaf area index and canopy temperature depression and spraying hormones on maize in drought stress condition in reproductive stage more effective than non-drought stress and vegetative drought stress conditions because it can be useful in balancing the disturb hormone relations.Conclusion Based on the result of this experiment, maize is tolerant to drought stress in vegetative stage, as a result, irrigation after soil moisture reached to 50% field capacity in vegetative stage and irrigation after soil moisture reached to 75% field capacity after tasseling stage can save irrigation water without any decrease significantly in physiological parameters at erase where water has been limited. Spraying cytokinin and auxin hormones in V8 –V10 and silk emergence stage can be recommended as the best time to use these hormones respectively. Using auxin and cytokinin hormones under drought stress condition in maize was more effective than control and vegetative stage because they can balance the disturbed hormones rate under that condition.
Farzaneh Fakhimi; Alireza Motallebi Azar; Fariborz Zaree Nahandi; Nemat Sokhandan Bashir; Gholamreza Gohari
Abstract
Introduction Potato (Solanum tuberosum) is an important crop in tropical countries. Salinity stress is the crucial factor that seriously limits agricultural production in various regions especially in arid and semi-arid areas. Salicylic acid is a bioactive molecule that synthesizes via enzymatic and ...
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Introduction Potato (Solanum tuberosum) is an important crop in tropical countries. Salinity stress is the crucial factor that seriously limits agricultural production in various regions especially in arid and semi-arid areas. Salicylic acid is a bioactive molecule that synthesizes via enzymatic and non-enzymatic pathways under stress conditions in different organs of plant, regulates and adjustments defense reactions of plant. Salicylic acid (SA) is known as a signalling molecule that modifies plant responses to pathogen infection. Many studies have shown that this compound can protect plant under oxidative stresses and maintain chlorophyll. In addition to being an important component of biotic stress tolerance mechanism, SA also regulates various aspects of plant responses to abiotic stresses through extensive signalling cross-talk with other growth hormones. However, exact mechanisms by which SA protects plants during abiotic stresses remain obscure. Salinity stress is the crucial factor that seriously limits agricultural production in various regions especially in arid and semi-arid areas. Salicylic acid is a bioactive molecule that synthesizes via enzymatic and non-enzymatic pathways under stress conditions in different organs of plant, regulates and adjustments defense reactions of plant. Salicylic acid (SA) is known as a signalling molecule that modifies plant responses to pathogen infection. Many studies have shown that this compound can protect plant under oxidative stresses and maintain chlorophyll. In addition to being an important component of biotic stress tolerance mechanism, SA also regulates various aspects of plant responses to abiotic stresses through extensive signalling cross-talk with other growth hormones. However, exact mechanisms by which SA protects plants during abiotic stresses remain obscure. Material and methods This experiment was conducted at the plant tissue culture laboratory of Horticultural Sciences, Department, University of Tabriz, Iran, during spring–summer of 2017. The present study was aimed to investigate of salicylic acid effect on betaine aldehyde dehydrogenase gene expression and glycine betainesynthesis in Solanum tuberosum cv. Agria under salinity stress on in vitro condition. The experiment treatments included four level of salycilic acid (0, 1, 10 and 100 mM) and two level of sodium chloride (0 and 70 mM). In the present study, MS media culture was used and sodium nitroprusside was applied for increasing the betaine aldehyde dehydrogenase gene expression (the responsible gene of glycine betaine synthesis) under salinity stress. Four weeks after treatment, total RNA of treated explants was extracted and semi quantitative RT-PCR was used for the analysis of expression of betaine aldehyde dehydrogenase gene. Results and semi quantitative RT-PCR was used for the analysis of expression of betaine aldehyde dehydrogenase gene. The glycinbetainecontent was measured with iodide potassium. The survey of betaine aldehyde dehydrogenase gene expression showed increased under salinity stress. Also salicylic acid increased the glycine betaine content in grown plantlets which were grown under normal condition.The expression pattern of glycine betain gene showed tha by increasing of salicylic acid and sodiuom chloride concentration the expression of glycine betain gene has been increased in all samples. however under salinity stress this compound showed negative effect on glycinbetaine content. ConclusionIn conclusion, antioxidant activity, total phenol and protein were increased salinity stress. In addition, antioxidant activity and glycine betaine content during salt stress period was decreased application of nitric oxide. The glycine betaine content of plantlets in general condition with application of sodium Salicylic acid increased but under salinity stress, Salicylic acid had negative effect on glycine betaine content. The results of this research showed that exogenous application of salicylic acid increased the expression level of genes and lead to enhancement of plant tolerance to salinity stress. Further studies are necessary to determine optimum concentration and duration of Salicylic acid application in order to achieve maximum benefit in Solanum tuberosum tissue culture.
Abbas Nameni; Alireza Abbasi; Manizhe Sabokdast
Abstract
Drought stress is one of the most destructive abiotic stresses. Expansins are one of the cell wall expandable proteins that can expand the cell wall under a pH-dependent pathway. Stomatal opening rate Due to the expression of AtEXPA1 gene in transgenic plants has been observed. In this study, second ...
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Drought stress is one of the most destructive abiotic stresses. Expansins are one of the cell wall expandable proteins that can expand the cell wall under a pH-dependent pathway. Stomatal opening rate Due to the expression of AtEXPA1 gene in transgenic plants has been observed. In this study, second generation (T2) of three transgenic tobacco lines with AtEXPA1 gene were studied for some physiological and biochemical traits under drought stress. Transgenic lines includes 2, 4 and 7 and Non-transgenic commercial cultivar Samson as control were cultivated. RWCL and leaf chlorophyll content has been reduced under drought stress, and ELIL, Lipid peroxidation as MDAL and leaf proline content has been increase. The activity of antioxidant enzymes such as, catalase (CAT), guaiacol peroxidase (GPOX), ascorbate peroxidase (APOX) and polyphenol oxidase (PPO) was increased in leaves under drought stress. In this study, according to biochemical traits Line 2 and Line 7 and according to physiological traits Line4 in Compared to the control cultivar, could cope with stress and introduce as tolerate cultivars.
Breeding plants for stress conditions
Morteza Shabannejad; Mohammad-Reza Bihamta; Eslam Majidi-Hervan; Hadi Alipour; Asa Ebrahimi
Abstract
IntroductionIt is expected that world wheat production would be about 761.5 million tons in 2020 while world demand would be doubled by 2025. Drought stress is one of the most important factors of yield loss that can decrease wheat production significantly. In the Middle East, drought stress usually ...
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IntroductionIt is expected that world wheat production would be about 761.5 million tons in 2020 while world demand would be doubled by 2025. Drought stress is one of the most important factors of yield loss that can decrease wheat production significantly. In the Middle East, drought stress usually happens at the end of the growing season and after the spike appearance. Late-season drought stress can slow down the seed development stage and decrease grain yield. In order to have stable food security one of the ways is to use the genetic diversity of germplasms.Materials and methodsAn association panel including 199 Iran bread wheat landraces was sown in Alborz and Zanjan provinces under late-season drought stress and normal irrigation conditions where climate zones are semi-arid. The experiments conducted using two alpha lattice designs with two replications for each of the conditions in each of the locations. The drip irrigation method was used for watering till spike appearance. Then, watering terminated for one of the designs whereas another design was normally irrigated for more three times in each location. Phenotypes measurements included days to heading, days to heading, duration of heading-to-maturity, plant height, grain yield/m2, thousand kernel weight, seed length, seed width, seed number per spike, spike length, spike weight, flag leaf length, flag leaf width, peduncle length, shoot diameter, and awn length.Results and discussionAgronomic traits varied lower under late-season drought stress conditions compared to normal irrigation conditions (except days to heading). Significant genetic effects observed for all of the traits under both irrigation systems. The genetic by environment effect was only significant for days to heading, days to heading, duration of heading-to-maturity, plant height, and grain yield. Heritability values were increased under normal irrigation conditions. Days to maturity and days to heading had lowest (0.35 and 0.47) and highest (0.85 and 0.86) heritability under both late-season drought stress and normal irrigation conditions, respectively. The highest correlation coefficients were achieved for the traits of days to heading and plant height (0.65) and grain yield/m2 with seed number per spike (0.60) under late-season drought stress conditions and the traits of days to heading and plant height (0.76) and spike weight with seed number per spike (0.64) under normal irrigation conditions. The first two components in principle components analyses were explained 0.40 of phenotypic variations under late-season drought stress conditions and 0.39 of phenotypic variations under normal irrigation conditions. A significant negative correlation was observed between days to heading and duration of heading-to-maturity under both late-season drought stress and normal irrigation conditions (-0.42 and -0.54, respectively). Using path analysis, thousand kernel weight (0.60) and seed number (0.79) under late-season drought stress conditions and days to heading (-0.57), days to maturity (0.40), duration of heading-to-maturity (-0.53), thousand kernel weight (0.52), and seed number per spike (0.81) under normal irrigation conditions had the highest direct effects on grain yield. The indirect effect of seed number through spike weight (0.51) on grain yield was highest under late-season drought stress conditions, and the indirect effect of days to heading through the duration of heading-to-maturity (0.42), as well as seed number through spike weight (0.52) on grain yield, were highest under normal irrigation conditions. The dendrograms obtained for grouping landraces showed a very good match with principal component analyses, while more landraces were placed in higher-yielding groups under normal irrigation conditions. The results showed that additional waterings increase grain yield in Iran bread wheat landraces. The landraces such as 57785, 57733, and 54502 are suggested to be used in applied breeding programs due to high yield performance under both late-season drought stress and normal irrigation conditions.ConclusionsThe results of this study suggest that the available genetic diversity of Iran bread wheat landraces be used in applied breeding programs.
Drought stress
Alireza Mehrinfar; Mohammad Rezaei Moradali; Tooraj Mir Mahmoodi; Saman Yazdan Seta; Suran Sharafi
Abstract
IntroductionAbsorption of nutrients from the soil depends on soil moisture, fertilizer application, soil nutrients and other factors. Foliar application of nutrients under water stress is one of the ways to reduce the effect of stress on the quantity and quality of agricultural products. Today, in many ...
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IntroductionAbsorption of nutrients from the soil depends on soil moisture, fertilizer application, soil nutrients and other factors. Foliar application of nutrients under water stress is one of the ways to reduce the effect of stress on the quantity and quality of agricultural products. Today, in many countries, a variety of organic acids such as humus fertilizers are used to improve the quantity and quality of crops and orchards. These fertilizers can be used with irrigation, foliar application, hydroponic cultivation, soil application and seed inoculation. One of the objectives of this project was to identify new wheat cultivars tolerant to water stress condition and use micro elements to introduce suitable cultivars and the effect of these elements in increasing grain yield.Materials and methodsIn order to study the effect of foliar application of nutrients on grain yield and grain quality of bread wheat cultivars in conditions of water stress, the field studies were carried out during 2017-2018 and 2018-2019 at the Agricultural Research Station of Miandoab, in West Azerbaijan province, Iran (46º 3´ E, 36º 58´ N, altitude 1142 m). The experiment was performed as a factorial split plot in a randomized complete block design with three replications. Irrigation treatments in the main plots were included stopping irrigation at flowering stage until maturity and full irrigation until seed maturity. Sub-plots were foliar application treatments with zinc, potassium, phosphorus, magnesium and humic acid with four cultivars of wheat included Orum, Zare, Mihan and Heidari Each plot was planted in six rows with a length of four meters and a width of 1.2 meters at row intervals of 20 cm. Foliar application of micro elements was at the time of spike emergence and before flowering. Grain yield in the final harvest stage and removal of half a meter from the beginning and end of each plot was performed by a combine of grain experiments. After final sampling, 30 g of seeds per plot after digestion was used to measure micro elements in the grain using an atomic absorption. Combined analysis of variance of data from two years of study and drawing graphs was performed using MSTATC, SPSS and Excel software.Results and discussionIn this study, foliar application of zinc, increased 1000-grain weight, grain yield, harvest index, iron, manganese, zinc, and copper content in grin under normal irrigation by 9.30, 15.99, 18.30, 35.35, 102.10, 18.34, and 20.45 percent respectively under normal conditions and by 9.73, 4.36, 9.00, 41.81, 65.51, 43.24 and 29.78 percent respectively under drought conditions, Under normal irrigation conditions, foliar application of zinc in Mihan cultivar had the highest 1000-grain weight, grain yield, harvest index, manganese, zinc, and copper content in grain. Under drought stress conditions, the highest 1000-grain weight, grain yield, harvest index, manganese, and zinc content were allocated to foliar application of zinc in the Mihan cultivar. In this study, foliar application with zinc, potassium, phosphorus, and humic acid treatments in Mihan cultivar had equal grin yield and more than the control foliar application under normal irrigation conditions and was able to replace some of the water requirement of plant, Therefore, foliar application of these treatments along with selecting the appropriate cultivar can be a solution to improve the quantitative and qualitative yield of wheat in areas where the plant experiences periods of water deficit stress with different intensities.ConclusionsConsidering the favorable effect of foliar application of nutrients, especially zinc and humic acid on the quality and quantity of wheat grains, it is suggested that extension projects be carried out to transfer these results to farmers. Also, due to higher grain yield and high grain quality of Mihan cultivar, it is suggested that this cultivar gradually replace the previous cultivars.
Drought stress
Raouf Seyed Sharifi; Reza Seyed Sharifi; Razieh Khalilzadeh
Abstract
IntroductionDrought stress is the most influential factors affecting crop yield particularly in irrigated agriculture in arid and semiarid regions. This stress induces various biochemical and physiological responses in plants as a survival mechanism (Tas and Tas, 2007). Drought stress have a direct impact ...
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IntroductionDrought stress is the most influential factors affecting crop yield particularly in irrigated agriculture in arid and semiarid regions. This stress induces various biochemical and physiological responses in plants as a survival mechanism (Tas and Tas, 2007). Drought stress have a direct impact on the photosynthetic apparatus, essentially by disrupting all major components of photosynthesis including the thylakoid electron transport, the carbon reduction cycle and the stomatal control of the CO2 supply, together with an increased accumulation of carbohydrates, peroxidative destruction of lipids and disturbance of water balance (Allen and Ort, 2001). It breaks down the balance between the productions of reactive oxygen species (ROS) and the antioxidant defense system causing the accumulation of ROS which induces oxidative stress to protein, membrane lipids and disruption of DNA strands (El Tayeb, 2006). Several strategies have been developed in order to decrease the toxic effects caused by severe water limitation on plant growth. Among them the use of vermicompost and nano silicon play a key role in yield improvement. The aim of this study was to investigate the effects of vermicompost and nano silicon application on yield and some physiological and biochemical traits of safflower under irrigation withholding conditon.Materials and methodsIn order to study the effect of vermicompost and nano silicon on yield and some physiological and biochemical traits of safflower (Carthamus tinctories L.) under irrigation withholding conditon, an experiment was conducted as factorial based on randomized complete block design with three replications in research farm of University of Mohaghegh Ardabili during 2019-2020. Factors experiment were included irrigation levels (full irrigation as control, irrigation withholding in 50% of heading bud and flowering stages as severe and moderate water limitation respectively) according with 55 and 65 BBCH code, foliar application nano silicon (foliar application with water as control, application of 25 and 50 mg.l-1 nano silicon) and application of vermicompost (no application of vermicompost as control, application of 4 and 8 t.ha-1). Vermicompost was purchased from the Gilda corporation. The safflower cultivar "Padideh" was used in the experiment with plant density of 40 seeds m-2. Chlorophyll and carotenoids were obtained based on method of Arnon (1967). The quantum yield was measured by the uppermost fool expanded leaf using a fluorometer (chlorophyll fluorometer; Optic Science-OS-30 USA). For this purpose, the plants adapted to darkness for 20 minutes by using one special clamp then the fluorescence amounts were measured in 1000 (µM photon m2s), and calculation was performed using following formula (Arnon, 1967):ØPSII = (Fm-F0)/Fm ØPSII; quantum yield amount of photosystem II, Fm or maximum fluorescence after a saturated light pulse on plants adapted to darkness and F0, the minimal fluorescence in the light adapted, which was determined by illumination with far-red light. To measure the enzyme activity, 0.2 g of fresh tissue was crushed by using liquid nitrogen and then one ml of buffer Tris-HCl (0.05 M, pH=7.5) was added. Obtained mixture centrifuged for 20 min (13000 rpm and 4 ºC), then supernatant was used for enzyme activity measurements. Catalase, Peroxidase and Polyphenol Oxidase activity was assayed according to Karo and Mishra (1976). Also, the evaluation of protein carried out by Bradford (1976) method, 0.2 g of plant tissue was squashed with 0.6 ml extraction buffer and was centrifuged at 11500 rpm for 20 minutes at 4 °C. The supernatant was transferred to the new tubes and centrifuged for 20 minutes at 4000 rpm. To measure the protein amount, 10 µl of obtained extract was added to 5 µl Bradford solution and 290 µl extraction buffer and the absorbance rate was read at 595 nm.Statistical analysis: Analysis of variance and mean comparisons were performed using SAS ver 9.1 computer software packages. The main effects and interactions were tested using the least significant difference (LSD) test at the 0.05 probability level.Results and discussionThe results showed that application of the highest nano silicon level under full irrigation increased chlorophyll a and chlorophyll b (74 and 145% respectively) in comparison with no application of nano silicon under irrigation withholding in heading bud stage. Means comparison showed that irrigation withholding in booting bud at the highest vermicompost level increased proline and soluble sugars content (149 and 99% respectively) and antioxidant enzymes activity such as catalase, peroxidase and polyphenol Oxidase (103, 82 and 94% respectively) in comparison with no application of vermicompost under full irrigation. Also, the highest vermicompost level under full irrigation increased chlorophyll a, quantum yield and grain yield (61, 62 and 119% respectively) in comparison with no application of vemicompost under irrigation withholding in heading bud stage.ConclusionIt seems that the application of vermicompost and nano silicon can increase grain yield of safflower under water limitation conditions due to improving physiological and biochemical traits.
Physiology of crops under stress conditions
Sajad Esapour Nakhjiri; Majid Ashouri; Seyyed Mostafa Sadeghi; Naser Mohammadian Roshan
Abstract
IntroductionDue to the continuous water shortages in rice cultivation areas, unbalanced use of nitrogen chemical fertilizers, the need to pay less attention to the use of water in rice cultivation and balance in the use of chemical fertilizers in saving and preventing water loss is important. Periodic ...
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IntroductionDue to the continuous water shortages in rice cultivation areas, unbalanced use of nitrogen chemical fertilizers, the need to pay less attention to the use of water in rice cultivation and balance in the use of chemical fertilizers in saving and preventing water loss is important. Periodic irrigation has been introduced as an important research finding to reduce water consumption and increase water use efficiency in paddy lands. As water stress increases, the uptake of nitrogen, phosphorus and potassium decreases.Materials and methodsTherefore, this study conducted for evaluation the effects of different irrigation regimes and N fertilizer on yield, and the content of micronutrients in brown and white rice was conducted in Rashat during cropping season of 2016-2017 and 2017-2018 in Rasht. Experiment was arranged in split split plot based on completely randomized block design with 3 replications in which water regimes were main factor included continuous submergence, 7 and 15 day interval irrigation and nitrogen fertilizer levels were sub factor included 50 , 75 , and 100 kg ha-1 and cultivars were sub sub factor included Gilanh and Hashemi. Before conducting the composite data analysis, Bartlett's test was used to ensure the homogeneity of experimental error variance. Analysis of variance and statistical calculations were performed using SAS software version 9.1 and the mean of the studied traits were compared using Duncan test at 5% probability level. In order to check the normality of the data, the normality test in SAS program was used.Results and discussionThe results showed that by increasing the irrigation interval, paddy yield decreased, while application of 75 and 100 kg ha-1 nitrogen fertilizer increased paddy yield in all three irrigation levels compared to the level of 50 kg ha-1 nitrogen fertilizer. There was a significant effect (at the level of one percent probability) between the treatment of irrigation regimes, nitrogen fertilizer and cultivar on brown and white rice and macro elements. The highest yield of rice for the Gilaneh variety was achieved under flooded irrigation treatment combined with the application of 100 kg ha-1 of nitrogen fertilizer, resulting in 12.4 T ha-1 in 2017 and 4.05 T ha-1 in 2018. Increasing the irrigation interval also increased the content of macro elements in brown and white rice. The highest protein content in brown rice was recorded at an average of 9.45% from the flooded irrigation treatment, with the application of 100 kg ha-1 of nitrogen fertilizer, specifically in the native Hashemi variety. The highest phosphorus in brown rice in the treatment of 7 days of irrigation, 75 kg of nitrogen per hectare in Gilaneh cultivar with a rate of 0.303% and the lowest amount in the treatment of 7 days of irrigation with 50 kg of nitrogen and in Gilaneh cultivar with 0.056 percent and the highest percentage of potassium in white rice in the treatment of 14 days of irrigation, 50 kg of nitrogen per hectare and in Hashemi cultivar with the amount of 0.246 percent and the lowest amount in the flooded treatment with Consumption of 50 kg of nitrogen in Hashemi cultivar was 0.143%.ConclusionThe results of this study showed that the application of nitrogen fertilizer has the ability to increase yield and yield components at all three irrigation levels and in both Hashemi and Gilaneh cultivars. In all three levels of irrigation in this study with increasing nitrogen fertilizer application with increasing vegetative growth, increasing the number of spikes per square meter, number of seeds per spike and paddy yield was observed. Consumption of 100 kg ha-1 of nitrogen fertilizer resulted in the highest yield of paddy in both cultivars and all three irrigation levels.
Mehrangiz Akbari; Mohammad Javad Zarea; Ali Ashraf Mehrab; Ali Asghar Nasrollah Nejhad
Abstract
In order to investigate the phosphorus and iron absorption rate and some of the physiological parameters in bread wheat (Sardari cultivar) and it's ancestral wild species for inbreeding selections and gene transportation, a factorial experiment based on randomized complete block design was conducted. ...
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In order to investigate the phosphorus and iron absorption rate and some of the physiological parameters in bread wheat (Sardari cultivar) and it's ancestral wild species for inbreeding selections and gene transportation, a factorial experiment based on randomized complete block design was conducted. In this experiment, physiological characteristics and absorption rate of phosphorus and iron in bread wheat and it's ancestral wild species (Triticum Boiticum , Aegilops speltoides , Triticum diccocoides , Aegilops tauschii) were investigated under the influence of P fertilizer (in 2 levels) and spraying Fe chelate (in 2 levels). Results showed that there were significant differences amongst different species in terms of phosphorus and iron concentration of shoot. Triticum Boiticum and Triticum diccocoides had the greatest phosphorus absorption rate, while Triticum Boiticum and Aegilops speltoides had the greatest iron absorption rate. Results showed that the application of P fertilizer increased the content of proline and soluble carbohydrates at flowering stage in all species especially the crop species (Sardari cultivar) as well as Aegilops tauschii, so that these species had the greatest proline and sugar content. Interaction effect of P fertilizer by species type on proline and soluble carbohydrates rate was significant.
Ali Senobar; S. Ali Tabatabayi; Farhad Dehghani
Abstract
To survey the effect of soil irrigation intervals on grain yield, yield components and harvest index of bread wheat cultivars, an experiment was conducted based on randomized complete blocks as a split plot design with 4 replicates during 2006-2007 at the experimental farm of Agricultural and Natural ...
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To survey the effect of soil irrigation intervals on grain yield, yield components and harvest index of bread wheat cultivars, an experiment was conducted based on randomized complete blocks as a split plot design with 4 replicates during 2006-2007 at the experimental farm of Agricultural and Natural Resources Research Center of Yazd. The main plots consisted of four irrigation treatments (8, 10, 12 and 14 days) and the sub-plots consisted of one line and three bread wheat cultivars (Backcross Roshan, Sistan, WS-82-9 and Pishtaz). The results indicated that the irrigation treatments had significant effects on grain yield, yield components and harvest index and there were significant differences between cultivars in terms of grain yield and yield components. Moreover, the interaction effect of irrigation interval x cultivar on grain yield and harvest index was significant (P<0.01). The maximum yield components and harvest index were obtained in 8 and 10 days intervals. 8 days interval showed the highest mean grain yield, while the lowest mean yield components, grain yield and harvest index were observed in 14 days interval. Comparison of the cultivars showed that Sistan and WS-82-9 had the maximum number of grains per spike and thousand kernel weight, respectively. Pishtaz and Backcross Roshan had the maximum number of spikes per square meter. Also, Sistan and Backcross Roshan had the highest grain yield while the maximum harvest index belonged to Sistan, Backcross Roshan and WS-82-9. Based on the study results, 8 days interval was recognized as a favourable irrigation period for achieving the greatest economical yield in the region, while WS-82-9 showed the greatest drought tolerance and Sistan was the most productive cultivar under well-watered conditions.
Ahmadreza Mohammadzadeh; Hamid Siadat; Ebrahim Pazira
Abstract
Salinity is a major environmental stress that drastically affects plant growth and productivity. To achieve optimal crop production in saline regions, the most appropriate, logical choice is growing salt-tolerant varieties best suited for these regions. A two year field study was conducted at two locations ...
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Salinity is a major environmental stress that drastically affects plant growth and productivity. To achieve optimal crop production in saline regions, the most appropriate, logical choice is growing salt-tolerant varieties best suited for these regions. A two year field study was conducted at two locations on saline soils of Nishabour to investigate the effect of salinity on growth and yield of 20 wheat (Triticum aestivum.L) genotypes. Two salinity levels were imposed on two silt loam soils by irrigating with saline waters. Electerical conductivities of applied waters were4 and 6-8 d Sm-1. The experimental design was a randomized complete block with three replications. The studied genotypes were Rowshan, Siossons, Falat, 4213, Qods, 4211*, Bezostaya, 4211, Alvand, Gaspard, Cross Shahi, Gaskogn, Marvdasht, Mahdavi, M.V.17, Hirmand, Alamoot, 4209, Cross Arvand and Chamran. Results of combined analysis of variances showed that the effect of year and genotype on grain, straw and biological yields were significant (P<0.01). In site 1, grain yield of line 4211* as a highest yield was 4167 kg ha-1. Rowshan cultivar had the highest straw and biological yields equal to 7833 and 11780 kgha-1 respectively. The lowest grain yield belongned to Falat cultivar (2650 kgha-1). Siossens cultivar had the lowest straw yield (4850 kgha-1).Generally, increase of salinity decreased grain and straw yields but straw yields reduction was less than grain yields. In site 2, Rowshan cultivar had the highest grain, straw and biological yields equal to 3867, 7893 and 11850 kgha-1 respectively. Lowest yields of grain (1567kgha-1), straw (2983kgha-1) and biological (4550kgha-1) yields belonged to Cross Arvand cultivar. According to obtained grain yield it seems that Rowshan and Siossons cultivars and line 4213 in comparison with other cultivars were preferable genotypes in saline condition. Rowshan, Cross Shahi and Alvand were superior cultivars evaluated for straw production in saline condition respectively .There is genetic variation for salinity tolerance in studied wheat cultivars and lines.
Khodadad Mostafavi; Reza Mirzaei; Mohammad Reza Bihamta; Mehdi Changizi; Taghi Babaei
Abstract
To study the genetics of drought tolerance in bread wheat, the bi-plot of diallel data was used. Parents (Alvand, Bezostaya, Navid, Roushan, Gaspard, Sardary and Shahriar) and their crosses (without reciprocal crosses) were studied in 2007 using a Randomized Complete Block (RCB) design with three replications ...
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To study the genetics of drought tolerance in bread wheat, the bi-plot of diallel data was used. Parents (Alvand, Bezostaya, Navid, Roushan, Gaspard, Sardary and Shahriar) and their crosses (without reciprocal crosses) were studied in 2007 using a Randomized Complete Block (RCB) design with three replications under normal and stress conditions. Analysis of variances indicated significant differences among genotypes for all traits. The GGE bi-plot graphical as well as AMMI methods were used for evaluation of cultivar potential. Investigated traits were 1000 kernel weight, kernel weight per plant, spike weight, spike length, plant height, awn length, peduncle length and kernel number per spike. For 1000 kernel weight, Roushan cultivar was the best general combinator. Moreover, Navid and Shahriar cultivars were the best specific combinatory, so that Navid × Shahriar cross was the best hybrid and for all other traits, the Alvand × Sardary was the best hybrid. These results were confirmed by AMMI method. Alvand cultivar was the best tester for 1000 kernel weight. For kernel weight per plant, Roushan cultivar, for spike weight, spike length, plant height and kernel number per plant Gaspard cultivar and for awn length and peduncle length Sardary and Alvands cultivars had the highest general combining ability
Behnam Firoozi; Omid Sofalian; Majid Shokrpour; Ali Rasoulzadeh; Fatemeh Ahmadpoor
Abstract
Drought stress is one of the most important environmental abiotic stresses that reduces crop yield especially in arid and semi-arid regions of the world. One of the useful strategies in regard to plant breeding for drought resistance is maintaining and exploiting the diversity that exists amongst different ...
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Drought stress is one of the most important environmental abiotic stresses that reduces crop yield especially in arid and semi-arid regions of the world. One of the useful strategies in regard to plant breeding for drought resistance is maintaining and exploiting the diversity that exists amongst different varieties. In order to identify the sources of resistance and drought tolerance indices, 39 varieties of spring wheat were cultivated in a split plot design with 3 replications in the Research Field of Faculty of Agricultur, Mohaghegh Ardabili University, Iran. Stress levels, which were arranged as the main plots, included control (full irrigation), 2/3 of irrigation requirement and 1/3 of irrigation requirement. Varieties were considered as sub plots. Under 2/3 irrigation, Sepahan, karaj3, Bahar and Yavaroos were the best varieties in terms of the Stress Tolerance Index (STI), Geometric Mean Productivity (GMP) and Harmonic Mean Productivity (HARM) indices; whereas under 1/3 irrigation, Hirmand, Bahar, Yavaroos and Marvdasht were the best ones based on the mentioned indices. Under non- stressed (control) conditions, the greatest grain yield correlation coefficient was obtained with STI, GMP and HARM, respectively, while under 2/3 irrigation, the greatest grain yield correlation coefficient was obtained with HARM, GMP and STI indices, respectively. Moreover, based on the biplot graph resulted from principle component analysis, in 2/3 irrigation, Moghan1, Golestan, Kavir, Maroon, Karkheh, Chanaab, Germezak, Tajan, Bahar and Sepahan; and in 1/3 irrigation, Golestan, Germezak, Niknejad, Maroon, Darab, Falat, Arta, Marvdasht, Bahar and Hirmand were the most tolerant genotypes.
Shahla Tawana; Jalal Saba; Farid Shekari
Abstract
Introduction With increasing the world population and need to provide food, the enhancement of crops yield has become very important. One of the most important actions to achieve this goal is to identify the factors affecting the enhancement of yield. based on studies conducted on balancing the yield ...
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Introduction With increasing the world population and need to provide food, the enhancement of crops yield has become very important. One of the most important actions to achieve this goal is to identify the factors affecting the enhancement of yield. based on studies conducted on balancing the yield components in so many crops was concluded that grain yield is a result of interaction between numerous genes and environment and for this reason direct selection has not proven so successful for that and does lead to remarkable increase in yield and so that the selection for yield components has been suggested as a solution for evermore progress in yield increase (Adams,1967). These results indicated that the number of spike/m2 was the trait related to higher grain yield under irrigated and late season water stress conditions (Okuyama et al., 2004). The correlation between yield and its components alone is not sufficient to understand the importance of each one of these components in determining the grain yield. while, path analysis not only measures the direct influence of one variable upon another, but also provides means of partitioning both direct and indirect effects and effectively measuring the relative importance of causal factors which helps to build an effective selection program (Ali and Shakor, 2012). This experiment was conducted to determine the most effective traits on grain yield and its components in bread wheat under rainfed conditions. Materials and methods A field experiment was conducted at the research farm of agricultural faculty of University of Zanjan, Iran (North Longitude 36°41', East Latitude 48°27' and 1620 m Altitude). A square lattice experimental design in two replications was conducted in 2012-2013. Evaluated traits included grain yield, number of spike per plant, number of grain per spike, 1000-grain weight, relative water content, rate of water loss from excised leaves, canopy temperature, difference of canopy with its environment temperature, stem diameter and number of xylem vessels. MSTAT-C and SPSS-20 software were used to analyze the data and LSD test was used to compare the means of traits at 0.05 probability level. The stepwise regression analysis was also carried out to test the significance of the independent variables affecting the grain yield. Then, path analysis was calculated for the traits. For this purpose, a simple coefficient correlation was obtained between all traits and the partial coefficient regression (direct effects) of traits was calculated by SPSS. The indirect effects were also calculated by multiplying the direct effects in simple coefficient correlation. Results and discussion Number of spike per plant and number of grain per spike had positive and significant correlation with grain yield with values of r = 0.41** and r = 0.36**, respectively. Previous authors also reported similar results for relationships of grain yield and these traits (Aycicek and Yildirim, 2006). No significant correlation was found between 1000-grain weight, Relative water content, number of xylem vessels and stem diameter with grain yield. Number of xylem vessels had negative and significant correlation with 1000-grain weight (r= -0.39**). Stepwise regression is a semi-automated process of building a model by successively adding or removing variables based solely on the t-statistics of their estimated coefficients. In order to remove effect of non-effective characteristics in regression model on grain yield, stepwise regression was used. Results of stepwise regression showed that the number of spike per plant, grain number per spike and 1000- grain weight with R square of 0.87, had justified the maximum of yield changes. Path coefficient analysis helps to estimate the influence of each variable upon the resultant variable directly as well as indirectly by partitioning the genetic correlation coefficients. Grain yield per plant was selected as resultant variable and number of spike per plant, number of grain per spike and 1000-grain weight as causal variables. The direct effect of number of spike per plant on grain yield was positive (0.89). The indirect effects of number of grain per spike and 1000-grain weight had values of -0.58 and 0.10, respectively. On the other hand, the traits leaf relative water content and stem diameter had positive and significant correlation with number of grain per spike. On the other hand, direct effects of stem diameter and relative water content on grain number per spike were recorded positive with values of 0.42 and 0.28, respectively. In other words, the increase in stem diameter and RWC can be somewhat increased the number of grains per spike in the experimental conditions. Conclusions Results of correlation analysis showed that selecting lines with more effective spikes and less number of grains per spike can be recommended as approach of indirect selection for improving grain yield in wheat under rainfed conditions. As a second approach, the selection for more grain per spike in limited number of spike is recommendable. Selection for greater stem diameter also can indirectly lead to grain yield improvement by increasing number of grains per spike.
Mohammad Hosein Najafi Mood; Ali Shahidi; Abbas Khashei Siuki
Abstract
In order to determine the best water- salt-quantitative parameters (number of bolls per square meter, boll weight, plant height, lint percentage) of cotton cultivars Varamin and Khordad, a research project examined the impact of salinity and irrigation water levels on yield and yield components of these ...
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In order to determine the best water- salt-quantitative parameters (number of bolls per square meter, boll weight, plant height, lint percentage) of cotton cultivars Varamin and Khordad, a research project examined the impact of salinity and irrigation water levels on yield and yield components of these two cultivars cotton in Birjand climatic conditions. The statistical design was a factorial randomized block split under climatic dry conditions with three levels of salinity and four levels of irrigation water. Sowing was done using basin method with dimensions of 4 x 5 meter on 28 April. Simple linear, Cobb-Douglas, quadratic and transcendental functions were used for this research. First, the results of functions coefficients tables and F value showed that all functions mentioned above were able to provide a determinant and significant estimation of the parameters the number of bolls per square meter, boll weight and plant height. Moreover, coefficients of determination of the plotted regression lines and the t-student statistic in regression line between the measured and predicted values confirmed the above results. So, the next step was to rank and identify the best function among them. To achieve this, five statistical parameters including root of the mean square error, coefficient of determination, modeling efficiency, the maximum error and coefficient of residual was used.The results obtained with both cotton cultivars of Varamin and Khordad showed that for the parameter of boll weight the quadratic function with a coefficient of determination of 80 and 89%,, respectively, and for the parameters of number of bolls per square meter and plant height transcendental functions with determination coefficients of 98, 95, 99 and 90% were able to be introduced as the superior functions amongst all others in the climatic area of Birjand. Additionally, none of the studied functions not able to provide an acceptable estimation of the lint percentage, because F value which showed the significant estimation of the studied parameters was not significant for the above mentioned parameter.
