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.
Abbas Khorami; Enayatállah Tohidinejad
Abstract
Water deficiency has increased the demand for cultivation of drought tolerant crops. In dry regions like most parts of Iran, ecotypes and local varieties often show a high degree of drought resistance. The experiment was arranged in a split plot based on a randomized completely block design that drought ...
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Water deficiency has increased the demand for cultivation of drought tolerant crops. In dry regions like most parts of Iran, ecotypes and local varieties often show a high degree of drought resistance. The experiment was arranged in a split plot based on a randomized completely block design that drought stress (50, 75 and 100% field capacity) were considered as main plot and genotype (Rabor, Golbaf and Pishahang) as subplot. The results showed that the traits of leaf water potential, reduction sugar, biological yield and grain yield significantly affected with drought stress at level of 1%. The simple effect of genotype was significant for mentioned traits and photosynthetic pigments. Based on variance analysis, the interaction of genotype×stress was significant only for ion leakage and biological yield. The results of mean comparison showed that drought stress significantly (P≤0.01) decreased biological yield, leaf water content and grain yield, while, ion leakage and reducing sugar contents were significantly increased. The highest biological yield was belonged to Pishahang cultivar in both of normal and stress conditions. Simple correlation among the traits showed that biological yield, relative water content and reduced sugars were the most effective traits on grain yield. In overall, the results showed that Golbaf genotype had the highest grain yield in comparison with Pishahang and Rabor genotypes under water stress conditions.
Mehdi Dahmardeh; Mahmood Mirbahodin; Isa Khammar
Abstract
Introduction One of the principles of sustainable use of bio-fertilizers and livestock in agricultural ecosystems in order to eliminate or reduce the use of chemical inputs.bio-fertilizers as an alternative and in most cases as a complement to chemical fertilizers can ensure the sustainability of agricultural ...
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Introduction One of the principles of sustainable use of bio-fertilizers and livestock in agricultural ecosystems in order to eliminate or reduce the use of chemical inputs.bio-fertilizers as an alternative and in most cases as a complement to chemical fertilizers can ensure the sustainability of agricultural systems (Han et al., 2006). Bio-fertilizers consisting of micro-organisms are useful that each one are produced for a specific purpose, such as nitrogen fixation, release of phosphate ions, potassium, iron, etc.These microorganisms are usually deployed around the roots, and plants will help nutrient absorption (Wu et al., 2005) and reduce plant disease, improve soil structure, further stimulate plant growth and increase in quantity and quality and to are increase its resistance to environmental stresses (Nagananda et al., 2010). Material and Methods The study in year 2014 with split plot experiment in a randomized complete block design with three replications. Main plot include drought stress with 3 levels (control, 50% water deficit, 90% water deficit and 75% water deficit) and sub plot was bacteria inoculation with tree levels (control, Azotobacter, Phosphate Barvar 2). Before conducting the experiment and to inform the physical and chemical soil sampling soil from a depth of zero to thirty centimeters and meters.Each plot consists of 4 lines of planting 3m in length and line spacing was 50 cm. Bean seeds, bio-fertilizers based treatments were impregnated and then planted. Based on experimental treatments of bio-fertilizers on the basis of 100 grams per hectare were impregnated and then cultivation. Results and disscussion The results were indicated that bio fertilizer on grain yield was significant. The results of the data analysis were showed that plant height is influenced by inoculation with biofertilizers and different levels of drought stress was significant. Bio-fertilizer was increased plant height, so that the maximum height of Phosphate Barvar 2 fertilizer treatments with an average of 75 cm -2 showed that compared to control and Azetobacter 40.34 and 16.79 percent respectively. Drought stress reduced plant height so that the maximum height of 50 percent of water deficit with an average 67.44 cm and minimum height was achieved of 90 percent of allowable deficit with an average 60.67 cm. The hight of pod length was obtained in biological phosphorous with an average of 13.11 cm was achieved compared to the control (no bio fertilizer) and Azotobacter fertilizer consumption increased by 135 and 31.89 percent. Also, the maximum of pod length was obtained at 50% water deficit that compared to other treatment (70 and 90% water deficit) was increased 8.12 and 20.67 percent respectively. Analysis of variance was showed that bio fertilizer in 1% level and drought stress treatments at 5% level was significant different on biological yield of bean. The highest and lowest biological yield was obtained of 50 % water deficit with 3704.11 kg/ha and 90% of the water deficit with 3505.78 kg/ha.The highest of economical yield obtained of biological phosphorous and 50% water deficit 2344 kg/ha.The greatest number of seeds per pod obtained in treatment of biological phosphorous an (9.76) that compared to the control (no bio-fertilizer), was increased 70.55%. The highest seed weight was observed in biological phosphorous with 16.95 grams and the lowest seed weight was obtained with 10.60 grams of control treatment. Overall, the results indicate that the seed inoculation with biological phosphorous can increase biomass, grain yield and components yield.
Roholla Moradi; Nasibeh Poorghasemian; Mahdi Naghizadeh
Abstract
Introduction Drought stress is one of the most important environmental stresses that disorder plant growth and development, and limit its production. Plants have different mechanisms to avoid the water deficit (Ali et al., 2007). However, some plants can’t tolerant and avoid of drought stress and ...
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Introduction Drought stress is one of the most important environmental stresses that disorder plant growth and development, and limit its production. Plants have different mechanisms to avoid the water deficit (Ali et al., 2007). However, some plants can’t tolerant and avoid of drought stress and need used some method and material e.g soil moisture absorbance material, organic and mineral fertilizer and osmotic regulator as salisylic acid, ascorbic acid and etc (Ashraf et al., 2007). Fertilization is one of the most important managements of agriculture which has significant effects on quantitative and qualitative increasing of agricultural plants. One of the aspects of sustainable agriculture to improve and maintain soil fertility and quality skins, through the use of organic fertilizers and fertilizer consumption balancing and consumption the product is developed. Application of cow manure could improve the mean weight diameter of aggregates, total porosity and water holding capacity of soils. Use of renewable sources of plant and animal life instead of chemical resources can play an important role in maintaining fertility and soil biological activities improve the quality of agricultural production and make ecosystem healthy.Nigella sativa (Black cumin) is an annual flowering plant, native to southwest Asia and used widely in traditional and industrial pharmacology (Salehi et al., 2014). Detailed investigations on medicinal plants have been less frequent than on agricultural crops especially under drought stress; therefore, their tolerance as-assessment for cultivation in arid and semi-arid areas is very important. The aim of the study was the applying some organic and mineral fertilizers as a strategy for holding moisture in soil and helping plant for avoiding drought stress. Materials and methods In order to investigate the effects of cow manure and chemical fertilizers interaction on some quantitative and qualitative characteristics of Nigella sativa L., an experiment was conducted as split-plot arranged based on randomized complete block design with three replications at experiment station of the Agricultural Faculty of Bardsir, Shahid Bahonar University of Kerman in 2015. Treatments were deficit irrigation levels (90%, 50% and 25% of the field capacity) assigned to main plot and nutritional resources (1- control, 2- NPK (200, 150 and 100 kg/ha, respectively), 3- cow manure (20 t/ha) and 4- NPK + cow manure) as subplot. The seedbed preparation was made based on common practices at the location. Plots size under the trial was 4 × 3 m so as to get 30 cm inter row spacing in six rows. Seeds were planted by hand. Drought treatments were start 10 days after plant establishment, and were performed by Time Domain Reflectmeter (TDR). In maturity stage, the traits of plant height, dry matter, branch number, follicles per plant, 1000 seed weight, harvest index, biological and seed yield, essential oil percentage and yield, and oil percentage and yield was estimated. Determination of essential oil and oil were done by Clevenger (Clevenger, 1928) and Soxhlet, respectively. Data were subjected to two-way analysis of variance (ANOVA) and the difference between treatment means was separated using Duncan test. A significance level of 95% was applied. Results and discussion: The results showed that irrigation treatments had a significant effect on plant height, branches number, follicles per plant, seed yield, biological yield, essential oil yield, oil percentage, oil yield, HI, essential oil percentage, seed per follicles. 1000-seed weight showed a non-significant effect as affected by the treatments. The traits were significantly reduced by decrease in field capacity. Nutritional resources showed also a significant effect (P<0.01) on all the studied traits except oil and essential oil percentage. The highest values of seed yield (648.8 kg/ha), HI (32.72%), oil yield (177.1 kg/ha) and essential oil yield (8.3 kg/ha) were assigned to NPK+cow manure treatment. Interaction of irrigation levels and nutritional resources had significant effect on branch number, seed yield, essential oil yield and oil yield. Application of all the nutritional resources improved all the mentioned traits. Nevertheless, the highest branch number (44), seed yield (817.3 kg/ha), essential oil yield (10.3 kg/ha) and oil yield (189.3 kg/ha) was related to NPK+cow manure treatment in both stress and non-stress conditions. Also, cow manure and NPK+cow manure treatments showed equal values of seed yield, essential oil yield and branch number at 50% and 25% of the field capacity. So, it seems that NPK+cow manure and cow manure treatments especially first treatment were the best treatment in both stress and non-stress conditions. Cow manure by improving the physical structure, balancing the chemical elements and increasing soil moisture contents capacity under drought stress conditions helps to providing water and nutritional require for plant. Also, NPK had beneficial roles in plant resistance to drought stress via improving nutritional supply. Conclusions Based on the results, it can be stated that application of NPK+cow manure had higher effect on all the quantitative and qualitative characteristics than other nutritional resources. It seems that in drought stress conditions, the role of cow manure in terms of their impact on the physical structures of the soil is more important than nutritional properties chemical fertilizers.
Mahdiye Askary; Mohammad Ali Behdani; Soheil Parsa; Majid Jami Al-Ahmadi; Sohrab Mahmoodi
Abstract
Introduction One of the negative effects of drought stress, reducing availability and absorption of nutrients for the plant(omidi, 2012). Manure increase soil fertility and improves the growth and yield(Fallah et al., 2007). This study conducted to evaluate some morphological and physiological characteristics ...
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Introduction One of the negative effects of drought stress, reducing availability and absorption of nutrients for the plant(omidi, 2012). Manure increase soil fertility and improves the growth and yield(Fallah et al., 2007). This study conducted to evaluate some morphological and physiological characteristics of two species of thyme plant under drought stress and manure. Materials and methods: Experiment was at the field of the Faculty of Agronomy of the University of Birjand, Birjand, Iran with located at latitude 53º: 32N, longitude 13:55ºE and altitude 1480 m above sea level in 2015.In order to evaluate the effects of different levels of drought stress and manure on Thymus vulgaris and Thymus danensis, an experiment was conducted as factorial based on a RCBD with 3 replications in 2015.Treatments were combination of three water stress levels 100% FC, 67% FC and 33% FC, manure at two levels: the no manure and consume 30 t.ha-1, and two species of Thymus vulgaris and Thymus daenensis. Measurements of Leaf pigments (Chlorophyll a and b, Carotenoid and concentrations): 0.1g samples were taken from the collected leaves. Subsequently each sample was extracted by 80% acetone and put in the centrifuges with rotation speed of 6000 per minute for 10 minute. Absorbance using a spectrophotometer at wavelengths of 470, 647, 663 nm was measured. Pigments were determined according to Lichthenthaler (1987). Measurements of Anthocyanin: 0.1g samples were taken from the collected leaves Subsequently each sample was extracted by methanol and put in the test tube in dark place for 24 hours then put in the centrifuges with rotation speed of 4000 per minute for 10 minute. Absorbance using a spectrophotometer at wavelengths of 550 nm was measured. Pigments were determined according to Wanger(1979). Measurements of Yield and yield components: For this purpose, three plants were harvested from crop lines. After drying the samples in an oven at 72 ° C for 48 hours the dry weight of stem, leaf, flower and total dry weight of each sample was measured. Statistical analyses were carried out by ANOVA, with a multiple range test (LSD) for subsequent pairwise comparisons. Data were analyzed using of SAS to compare the difference between the treatments. Results and Discussion: Leaf pigments: The highest Ch a, b obtained from of Thymus danensis. Carotenoid content increased under drought stress. The highest and lowest Carotenoid content obtained from of 33% Fc(The highest level of drought) and 100% Fc(normal condition) respectively. Among species, Thymus vulgaris showed the highest and Thymus danensis showed lowest Carotenoid content respectively. Manure while reducing the effects of drought stress and Cha, b increased under 30ton.ha-1 manure but manure reduced the amount of carotenoids. Anthocyanin: Anthocyanin content was increased under drought stress levels. The highest and lowest Anthocyanin contents were obtained from of 33% Fc(The highest level of drought) and 100% Fc(normal condition) respectively. Among species, Thymus vulgaris showed the highest and Thymus danensis showed lowest Carotenoid content respectively. Also the highest and lowest Anthocyanin content obtained from of no manure and 30ton.ha-1 manure respectively. Leaf and shoot dry weight: Leaf and shoot dry weight decreased under drought stress. The highest and lowest Leaf and shoot dry weight obtained from of 100% Fc(normal condition) and 33% Fc(The highest level of drought) respectively. Thymus danensis showed the highest and Thymus vulgaris showed lowest Leaf and shoot dry weight respectively. Among manure treatment, 30ton.ha-1 manure showed the highest Leaf and shoot dry weight. Leaf dry weight to shoot: The highest and lowest Leaf dry weight to shoot obtained from of 100% Fc(normal condition) and 33% Fc(The highest level of drought) respectively. Leaf dry weight to shoot increased drought 30ton.ha-1 manure and the highest Leaf dry weight to shoot obtained from of 30ton.ha-1 manure. Flower dry weight: The highest and lowest Flower dry weight obtained from of 100%Fc and Thymus danensis and 33%Fc and Thymus vulgaris respectively. Manure reduced the effects of drought stress and the highest and lowest Flower dry weight obtained from of Thymus danensis and 30ton.ha-1 manure and Thymus vulgaris and no manure respectively. Total Dry Matter: The highest and lowest total dry Matter obtained from of 100%Fc and Thymus danensis and 33%Fc and Thymus vulgaris respectively. Interaction of manure in species showed that the highest and lowest total dry matter obtained from of Thymus danensis and 30ton.ha-1 manure and Thymus vulgaris and no manure respectively. Conclusions: The main goal of this study was the selection of species that contain higher yield. Where in this study the Thymus vulgaris demonstrate the highest pigment and the highest yield compared to the Thymus vulgaris Therefore, According to these results we can say Thymus daenensis can grow successfully in arid and semi-arid. Also application of manure on food and water resource management and drought stress conditions in order to achieve the desired yield is recommended.
Hamid Reza Fanaei; Gholam Ali Kaikha; Mansoor Saranei; Alireza Akbarimoghadam; Farnaz Shariati; Mohammad Khajedad Keshtkar
Abstract
Introduction Drought stress is an important factors limiting growth and yield in crops that influencing 60% of agricultural lands in world (Shao et al., 2006). Rapeseed is one most important oil seeds in many arid and semi-arid regions, which often yield its limited due to water shortages and high temperatures ...
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Introduction Drought stress is an important factors limiting growth and yield in crops that influencing 60% of agricultural lands in world (Shao et al., 2006). Rapeseed is one most important oil seeds in many arid and semi-arid regions, which often yield its limited due to water shortages and high temperatures during reproductive period (Ahmadi and Bahrani, 2009). The water deficiency can influence inversely the grain of canola but this effect depends on the genotype and, development and growth stage the plant adaption to the drought (Azizi et al., 1999). Increase percentage of seed and Silique abortion due to the reduction in provides photosynthetic products in the last season stress has been reported important reson reduction yield in rapeseed (Fanaei et al., 2013). Ahmadi and Bahrani (2009) reported that highest plant height, Siliques per plant, grain yield and oil yield were obtained in the full irrigation treatments, and the flowering was the most sensitive stage. Majidi, (2012) reported there is a significant variation in the tolerance to drought stress among cultivars and hybrids canola. This experiment was conducted with the aim of determining most suitable time for the last irrigation for to minimize reduction grain and oil yield in canola cultivars. Materials and Methods In order to evaluate grain yield, oil and some agronomic traits of canola (Brassica napus L.) cultivars in final irrigation times an experiment as split-plot was conducted based on randomized complete blocks design with 3 replications in Zahak research station during three cropping seasons (2008, 2009 and 2010). Time of irrigation were at six levels: (I1=Last irrigation 5 days after end of flowering), I2= Last irrigation at 20 percent remained flowers in plants, I3= Last irrigation in start of color changing in siliqes of origin stem. I4= Last irrigation at 50 percent of Siliqueding. T5= Last irrigation at 10 percent of color that changed in siliqes of origin stem. I6= Last irrigation in flowering, these treatments were assigned as main plots and rapeseed cultivars at three levels including; (V1= Hyola 401 V2=RGS003 and V3=Sarigol) were assigned as sub-plots. Fertilizers were applied at ratio of 150 kg/ha super-phosphate triple, 200 kg/ha sulphate dipotash, respectively prior to sowing, along 180 kg/ha pure N based on Urea at ratio 40,30 and 30 percent prior to sowing, rosset and flowering start stages respectively. All other agricultural practices were performed when they were required. A random sample of five plants was selected from each plot in physiological ripening to estimate the different parameters. Data were analyzed by using MSTAT-C statistical package. Duncan Multiple Range Test was used to do mean comparisons Results & Discussion The effect Time of irrigation and cultivar were showed significant different on grain yield, components yield. Highest number of Siliques per plant and seed in Silique were produced in I1 (control) and I3 treatments with a mean 167 and 160 Siliques in plant and 22 and 21 seed in Silique respectively and lowest achieved in I6 treatment, with mean of 123 Siliques in plant and 18 seed in Silique. It seems that water deficiet in during reproductive phase causing Silique decreases by increasing the flower and Silique abortion. Many researchers have reported that flowering and Silique development stages have a high sensitivity to drought stress (Ahmadi and Bahrani, 2009؛ Fanaei et al., 2013). The highest number of seeds per silique, seed in Silique and 1000 seed wieght belonged to Hyola 401 and RGS003. Among levels of irrigation time, the highest 1000 seed weight was observed in treatments I3 (3.6 g), I1 (3.5 g), I4 (3.48 g) and lowest 1000 seed weight with mean 2.97 g in I6 treatment. The highest grain yield was applied to I1 treatment, and I3 treatment, the highest grain yield was applied in I1, and I3 treatments respectively with mean of 3340 and 3132 kg/ha. In these treatments, enough provide of water during growth different stages due to positive effect on yield components caused improved seed yield of canola. It has been determined that the flowering and Silique development stages have a high sensitivity to drought stress and stress in these stages will caused to more reduction in grain yield (Ahmadi and Bahrani, 2009؛ Fanaei et al., 2013؛ Sinaki et al., 2007؛). Hybrid Hyoli 401 and RGS 003 had the highest grain yield with 3169 and 3029 kg ha-1. Conclusion Based on the result, it can be concluded terminal irrigation for high grain and oil yield could be conducted 5 days after end of flowering or in start of color changing in siliques of origin stem in both Hyola401 cultivar and RGS003 in Sistan and similar regions.
Ezatollah Farshadfar; Reza Amiri
Abstract
Introduction Drought as one of the most important environmental stresses and limiting production of crops such as wheat, often leads to a significant decline in production. Identify and use specific physiological traits in breeding programs and also producing cultivars with characteristics consistent ...
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Introduction Drought as one of the most important environmental stresses and limiting production of crops such as wheat, often leads to a significant decline in production. Identify and use specific physiological traits in breeding programs and also producing cultivars with characteristics consistent with drought conditions is one of the most important steps in drought stress studies. The aim of this study was to evaluate the diversity of bread wheat landraces in response to drought stress based on some agro-physiological traits (grain yield, gas exchange parameters, relative water content, chlorophyll and carotenoid contents) and also to exploring the possibility of selecting superior agro-physiological traits in identify drought tolerant genotypes using integrated selection index. Materials and methods This experiment was conducted on 19 landraces of bread wheat in a randomized complete block design with three replications under normal and rainfed conditions in the Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran during 2011-2012 cropping season. Sowing was done by hand at five row plots, 2 m length, and 0.20 m row spacing as 400 seeds per square meter density. Chemical fertilizers were not used during the research. The weeds control wad done by hand and using 2,4-D herbicide before stem elongation stage of wheat. Non-stressed plots were irrigated according to regional needs at heading, flowering and kernel filling stages. At full physiological maturity, two middle rows of each plot at both conditions were harvested to determine kernel yield per unit area. Results The mean of grain yield in irrigated and rainfed conditions were 1651 and 1273 Kg/ha, respectively, means that drought stress reduced grain yield as much as 22.86% but it increased proline by 253%. The considerable variation was not observed among genotypes in both conditions for gas exchange traits, except stomatal conductance. All the gas exchange-related traits were reduced due to drought stress so that the stomatal conductance had the highest reduction by 45%. Genotypes number 4, 9, 18 and 11 were known as tolerant genotypes based on all studied traits using integrated selection index. In ranking method which calculated based on all studied traits under rainfed conditions, mean rank, standard deviation of ranks and rank sum parameters, genotypes number 5, 2, 15 and 18 with the lowest rank sum were identified as the most drought tolerant genotypes by consideration the rank of each genotypes for kernel yield under both conditions, the value of studied traits and the integrated selection index, while genotypes number 3, 9, 13 and 10 as the most sensitive. In examining the relationship between various physiological indicators of drought tolerance, grain yield under both conditions and integrated selection index, using Biplot, the PCA1 and PCA2 axes justifed 51.46 % of total variation. Conclusions Integrated selection index introduced genotypes 4 (WC-4530), 9 (WC-47381), 18 (WC-47636) and 11 (WC-4566) as the most drought tolerant. Principal component analysis showed that integrated selection index (ISI) had close relationship with chlorophyll a, chlorophyll b, carotenoid, leaf temperature, proline concentration, photosynthesis rate, stomatal conductance and grain yield under both conditions, therefore these traits were identified as superior traits for selecting drought tolerant genotypes using biplot graph.
Abbas Rezaizad; Soraya Parvin; Lia Shoshtari
Abstract
Introduction Turn to occurrence of drought stress in recently years, it asks for attention drought stress conditions has to be considered in plant breeding programs also combining ability determination of inbred lines derived from plant breeding programs. It could be useful to determine drought stress ...
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Introduction Turn to occurrence of drought stress in recently years, it asks for attention drought stress conditions has to be considered in plant breeding programs also combining ability determination of inbred lines derived from plant breeding programs. It could be useful to determine drought stress tolerant genetic materials. Production of hybrid cultivars due to high yield, uniformity in maturity and agronomic characteristics and resistance to disease has been popular among plant breeders. Identifying suitable parent lines for production hybrid cultivars under drought stress conditions is very important. For this it has to be identified inbred lines with high general combining ability and then Identifying lines with specific combining ability for important agronomic traits under both normal and drought stress conditions. Materials and methods In order to production new sunflower hybrids and evaluated of general and specific combining ability of some sunflower inbred and restorer lines, in first year of this project 4 inbred lines and 3 restorers (this materials are belonged to oilseed department, seed and plant improved institute) has been selected for crossing. In second years, 12 derived hybrids along with Farokh and SHF-81-90 as checks were evaluated using RCBD design with 3 replications under normal and drought stress conditions. Under normal conditions irrigations has been occurred as usual so that plants did not encountered to drought stress in non vegetative or reproductive stages and under drought stress conditions irrigation has been deleted from flowering stage. Some important agronomic traits such as days to maturity, plant height, head diameter were recorded based on Schneiter and Miller, 1981 instruction. Grain yield was accented using harvesting two rows of each plot with one plant deleted from head and end of each plot. Seed oil content was measured using NIR instrument model DA7200. Results Combined variance analysis showed that drought stress had significant effect on all traits exception seeds per head. The most reduction due to drought stress belonged to seed yield and 1000 seed weight and the least reduction belonged to seed oil content percent. Variance analysis of combining ability showed that effects of CMS and restorer lines (general combining ability) were statistically significant for most traits under normal and drought stress conditions. Results showed that restorer lines had more portion than it in CMS lines for genetic variation. Significant effects for CMS and restorer lines in addition to their interaction effect showed that most evaluated traits were controlled by both additive and dominant gene effects.
Hasan Tavizi; Sohrab Mahmoodi; Sayed vahid Eslami
Abstract
Introduction Cumin (Cuminum cyminum L.) is the most important medicinal plant in Iran that main part of its production costs spends on combat weeds. Given the difference among different species in water use patterns and techniques for moisture stress resistance, it may be feasible to manage weeds by ...
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Introduction Cumin (Cuminum cyminum L.) is the most important medicinal plant in Iran that main part of its production costs spends on combat weeds. Given the difference among different species in water use patterns and techniques for moisture stress resistance, it may be feasible to manage weeds by irrigation practices (Zand et al., 2010). In an in-depth review of literature on the competition between weeds and crops for water, Patterson (1995) concluded that lower soil moisture sometimes benefits crops by weakening weeds’ competitiveness. It seems that cumin is of those crops that have a competitive advantage in arid climates. The growth of cumin so extensively accompanied with dryness that most farmers know it as a rain-fed crop (Kafi et al., 2002). Research on weeds of cumin farms in Southern Khorasan Province shows that false barley (Hordeum murinum L.) is the most prevailing narrow-leaf weed in the region (Amininasab, 2014). Seemingly, the competition between cumin and weeds has not been studied comprehensively. Therefore, it appeared necessary to carry out a study to assess the effect of drought stress on the competition between false barley and cumin. Materials and Methods The study was carried out in the experimental greenhouse of Faculty of Agriculture in Birjand in February-March 2015 on the basis of a Randomized Complete Block Design with four replications. The studied factors including the density of false barley at four levels (0, 1, 3, and 5 plants per pot equivalent to 0, 26, 79, and 131 plants per m2) and soil moisture relative to field capacity (FC) at three levels of normal conditions (soil moisture = FC), moderate stress (soil moisture = 60% FC) and severe stress (soil moisture = 30% FC). Cumin density was five plants per pot (131 plants per m2) in all treatments. Plastic pots were used in the present study with capacity to hold 6 kg soil, mouth diameter of 22 cm, and depth of 21.5 cm. According to field capacity determined in the laboratory, the water required for 100%, 60% and 30% FC was 750, 450 and 225 cc, respectively. To keep the pre-determined moisture levels, all pots were weighed every day and the required water was added. The recorded growth and yield measures of cumin included the changes in height, leaf number, individual plant yield, total biomass, and seed number. Data were analyzed by DSAASTAT macro ver. 1.022 in MS-Excel Software Package. Also, means were compared by FLSD test at the 5% significance level, and the graphs were drawn by MS-Excel Software Package. Results and discussion It was found that drought stress significantly affected the loss of some growth and yield measures of cumin including plant height, leaf number, total biomass, root length, and individual plant yield at the 1% level, whilst the effect of weed density and the interaction between weed density and drought stress was significant for total biomass, leaf number, and plant yield at the 1% level and for plant height at the 5% level. They were not significant for root length. According to the results, adequate soil moisture increased inter-species competition of false barley, and weed density had higher negative impact on cumin yield. In these conditions, weeds occupied whole pot space at the density of three plants per pot, whilst cumin yield showed more stability at different weed densities under drought stress of 30% FC. It can be said that when soil moisture was not limited, false barley exploited the favorable conditions better than cumin and reduced its growth by limiting the space and using nutrients and water. In total, it was revealed that the highest cumin yield was obtained from adequate moisture and no-weed conditions. Also, under the lack of soil moisture limitations, false barley at the density of three plants per pot (79 plants per m2) incurred the greatest damage to cumin. So, it seems necessary to irrigate cumin farms adequately and to remove false barleys, especially under adequate soil moisture. In addition, the full removal of false barleys after cumin harvest will be a suitable managerial approach.
Ali Ghotbi; Elnaz Farajzadeh Memari Tabrizi
Abstract
Drought stress is one of the most important environ-mental factors in reduction of growth, development and production of plants. It can be said that it is one of the most devastating environmental stresses. Iran, with an annual rainfall of 240 mm, is classified as one of those dry regions Moisture stress ...
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Drought stress is one of the most important environ-mental factors in reduction of growth, development and production of plants. It can be said that it is one of the most devastating environmental stresses. Iran, with an annual rainfall of 240 mm, is classified as one of those dry regions Moisture stress is a limiting factor for crop growth in arid and semi-arid regions due to low and uncertainty precipitation. Water stress due to drought is probably the most significant abiotic factor limiting plant and also crop growth and development. Priming is one of the seed enhancement methods that might be resulted in increased seed performance (germination and emergence) under stress conditions, such as salinity, temperature and drought stress. also Priming is one of the simple and effective methods in decreasing drought effect on plants. This research had don in order to investigate effect of different irrigation regimes (irrigation after 70, 110 and 150mm evaporate from evaporate basin)and different priming treatments ( control, hydropriming, priming with iron, zin and manganese) on growth and yield of sugar beet in three replication as split plot based on complete block design. Based of results drought decreased root and sugar yield.increase in water shortage caused more reduction. Root and sugar yield decreased 38 and 41.8 % due to irrigation after 110mm evaporate from evaporate basin and irrigation after 150mm evaporate from evaporate basin than irrigation after 70mm evaporate from evaporate basin. But priming also increased this two traits. Seed priming with iron caused 25.5 and 35.4 % increament and Seed priming with zinc caused 25.5 and 34.4 % increment in root yied and sugar yield respectively. Other priming methods did not had any effect on this traits. Highest sugar content also obtained in iron and zinc priming. But water shortage also decreased growth properties of sugaar beet such as leaf area and biomas, but priming had posetive effect on most of growth and reproductive traits of sugar beet.in this investigation priming in water shortage also caused an increase in most of traits. Highest wet biomass, root length and leaf wet weight observed in irrigation after 70 mm evaporate from evaporate basin and priming with iron, Least values observed in irrigation after 150 mm evaporate from evaporate basin and without priming. Thus this investigation shows the importance of priming in decreasing drought effect and increasing growth and yield of sugar beet in full rrigation and water shortage. Over and manganese water treatment effect on percent sugar, sugar yield and sugar beet root yield was not. The largest increase in leaf area was the priming on, but the highest sugar content, sugar yield and root yield in terms of sugar beet seed priming with iron and zinc were obtained and statistically significant difference was observed between these traits. In general, it was observed that the iron treatments and the best pre-treatments to enhance growth and yield of sugar beet seed under irrigation and dehydration. By step by step regression analysis three trait of root yield, sugar percent and dry biomass entered as effective traits on sugar yield that explain 99 % of changes. Root yield was the first trait that entered the model.
Reza Siyami; Bahram Mirshekari; Farhad Farahvash; Varham Rashidi; Alireza Tarinejad
Abstract
Introduction and Objectives Seed pre-treatment before sowing is a considerable solution that generally enhances the absorption of moisture, nutrients, and sunlight that therefore results in the better performance of the seeds. The negative effects of the occurrence of water deficit stress on the growth ...
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Introduction and Objectives Seed pre-treatment before sowing is a considerable solution that generally enhances the absorption of moisture, nutrients, and sunlight that therefore results in the better performance of the seeds. The negative effects of the occurrence of water deficit stress on the growth and corn yield depends on the time the stress occurs, the stage of the growth, the amount of shortage, and the environmental changes during the draught period. Among the different methods of priming, there has been a recent growing interest in using physical methods for the priming of seeds that is due to the positive effects it has on the growth of the plants. Using a number of physical factors is considered to be part of a modern method to obtain better performance in the agricultural system. The present experiment aims at investigating the effect of physical priming of seeds and water deficit stress on the enzyme activity and corn yield and also feasibility of reducing water deficit effects by using different physical priming ways. Materials and Methods The experiment was conducted as split plot based on completely randomized block design with three replications at the Agricultural Research Station of Islamic Azad University, Tabriz Branch located 15 km east of Tabriz during 2014. The main factor was consisted of two levels of normal irrigation and water deficit based on 70 (control) and 110 mm evaporation from evaporation pan respectively beginning from 8-9 leaves stage. The sub-factor was in 11 stages including the seed treatment of the corns by different rays of gamma, beta, laser, magnetic fields and ultrasonic waves in two different durations of 5 and 10 minutes along with a controlled group, that did not receive the treatment. Before applying the physical treatment, the seeds were washed and disinfected with sodium hypochlorite after which the physical pre-treatments were applied to the seeds and they were immediately sowed in the farm. The variance analysis of the data was performed by MSTAT-C software. The comparison of the means was done by Duncan with 5% of probability. Results The tallest plants were obtained from normal irrigation treatment whereas the shortest ones resulted from the plants with water stress. The corns exposed to the treatment of magnetic field for 5 and 10 minutes and also gamma and laser rays for 5 minutes were the highest plants. It is noteworthy that with the increase of the duration of exposure of the seeds to gamma and laser rays the height of the plants decreased. With the occurrence of water deficit stress, the activity of peroxidase enzyme increased by 40% compared to normal irrigation. The maximum activity of peroxidase enzyme was obtained after the treatments of 5-minute gamma rays, 10-minute magnetic field, 5-minute laser rays, 10- minute beta rays and 5-minute magnetic field. The occurrence of water stress enhanced the activity of superoxide dismutase compared to normal irrigation. The maximum amount of superoxide dismutase was obtained from the seed pre-treatment by laser ray for 5 minutes (95.79) and 5 and 10 magnetic fields as 80.88 and 75.39 micromoles per minute per gram respectively. The effects of water deficit stress and the physical seed pre-treatment were not meaningful on the number of seed rows of the maize. Due to the application of water deficit stress, an amount of approximately 170 grams per Sq.m. of the biomass of the corn reduced in comparison to normal irrigation. Following the treatments of 5-minute laser ray, and 5 and 10- minute magnetic field an average amount of 16% was added to the biomass of the corns, whereas the minimum amount (945 grams per Sq.m.) was obtained with the treatment of 10-minute gamma ray. The occurrence of tension after the 8-9 leaves stage resulted in the 18.5% decrease in the performance of the corns. The treatments of 5 and 10-minute magnetic field, and 5-minute gamma and laser rays had the maximum performance of the seeds with the average of 685 grams per Sq.m., while the increase of the time of seed pre-treatment with gamma and laser rays from 5 to 10 minutes reduced the performance of the seeds by 20% and 17%. The seed treatment by beta ray and ultrasonic waves for both 5 and 10 minutes did not result in any considerable changes in the performance of the treated seeds compared to the controlled seeds. Conclusion The occurrence of water deficit stress after the 8-9 leaves stage reduced the performance of the corn seeds up to 18.5%. It seems that corn seed priming with magnetic fields and gamma and laser rays only in short terms reduces the adverse effects of drought stress and finally increases the grain yield.
Fariba Morsali Aghajari; Reza Darvishzadeh; Hamid Hatami Maleki
Abstract
Introduction Salinity is one of the most important abiotic stresses that has a negative effect on the growth and productivity of plants cultivated around the world by reducing soil fertility. Unfortunately, due to inefficient irrigation management of agricultural fields, high exploitation of agricultural ...
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Introduction Salinity is one of the most important abiotic stresses that has a negative effect on the growth and productivity of plants cultivated around the world by reducing soil fertility. Unfortunately, due to inefficient irrigation management of agricultural fields, high exploitation of agricultural soil and rising ground-water levels, the area affected by soil salinity is increasing every year. For utility of lands affected by salinity or using salty water resources, identification and selection of salt tolerant genotypes are important. Sunflower botanically is a dicotyledonous, annual, monoicous plant from North America. The plant is often cultivated for its edible oil. Different criteria are proposed for selecting genotypes on the basis of their appearance in stress or non-stress environments. In general, a criterion is considered as the best index for determining drought tolerance genotypes when it is highly correlated with plant performance in both normal and stress conditions. In such a case this index is able to identify genotypes with high performance in both environments. Since for calculating tolerance indices need to evaluate genotypes in both normal and stress conditions; by identifying molecular markers associated with tolerance indices, it will be possible to select tolerant genotypes in normal conditions at seedling stage. The aim of this research is to identify molecular markers associated with salt tolerance indices in order to use them in sunflowers salt tolerance breeding programs. Materials and methods In this study, 59 recombinant inbred lines (F9) of sunflower coming from the cross between PAC2 (maternal) × RHA266 (paternal) accompanied with their parental lines were evaluated in both normal and salt stress conditions. The factorial experiment was conducted in completely randomized design with three replications in Urmia University. Several tolerance indices including mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM), stress tolerance index (STI), yield stability index (YSI) and tolerance index (TOL) were calculated based on yield performance under normal and salt stress conditions. In order to identify molecular markers associated with salt tolerance indices, a genetic linkage map including 210 SSR and 11 SNP markers on 17 linkages groups with average distance of 7.44 CM between marker pairs were used. Identification of QTLs linked to tolerance indices was performed by QGene software via composite interval mapping method (CIM). Results and discussion Considering simple correlation results, high correlation was observed between yield under normal and salinity conditions with mean productivity, geometric mean productivity and harmonic mean. So, these indices are introduced as the most appropriate measures to identify sunflower lines tolerant to salinity stress. Based on three dimensional plots constructed by yield in normal and salt stress conditions and each one of appropriate indicators (GMP, MP and HM), lines such as C86, C61, C142, C134a, C62, C70a, LR1, C153, C108, C6, C106, C98b and C148 are considered as salt tolerant lines. In QTL analysis, totally 5 QTLs was identified significantly associated with salt tolerance indices. The results indicate co-localization of the identified QTLs for GMP, MP and HM in linkage group 14 with QTL identified for grain yield under salt stress conditions. Conclusions The results support the phenotypic correlations observed between grain yield and salt tolerance indices. After validation and fine mapping of genomic regions associated with salt tolerance indices, they can be used for MAS (marker-assisted selection) in sunflower breeding programs. This leads to increase the efficiency of traditional breeding methods.
Mohammad Amirian Mojarrad; Mohammad Reza Hassandokht; Vahid Abdossi; Seyd Ali Tabatabaei; Kambiz Larijani
Abstract
Introduction Salinity is a multidimensional stress affecting crop yield and productivity at various levels of plant organization. The plant response to salinity consists of numerous processes that must function in coordination to alleviate both cellular hyper osmolarity and ion disequilibrium. In addition, ...
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Introduction Salinity is a multidimensional stress affecting crop yield and productivity at various levels of plant organization. The plant response to salinity consists of numerous processes that must function in coordination to alleviate both cellular hyper osmolarity and ion disequilibrium. In addition, crop plants must be capable of satisfactory biomass production in a saline environment (yield stability). Excess of salt concentrations causes enhanced generation of reactive oxygen species (ROS) in plants. In contrast, plants are equipped with a diverse array of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) against oxidative damages by reactive oxygen species. Turnip (Brassica rapa L. subsp. Rapifera) as a source of strong health food, contain a variety of antioxidants and Iran is one of the main centers of diversity. Indigenous accessions has a set of morphological, physiological and phenologycal that increase water use efficiency in the soil in saline and dry environments. Study of physiological and biochemical changes made in understanding the mechanisms of resistance to salinity stress conditions and access to genetic resources for breeding programs is essential. According to the limited information available in the field of physiological and biochemical reactions turnip cultivars to salinity, especially in indigenous accessions, in order to determine the response of morphological, biochemical and enzymatic turnip indigenous masses to salinity, the research carried out was. Materials and methods This study aimed to assess the response of Iranian indigenous turnip accessions to salinity stress in terms of biochemical traits and antioxidant enzymes activity, to further understanding of salinity resistance mechanisms in plants and access to better genetic resources. The indigenous turnip accessions including Ardakan, Shiraz and Kermanshah evaluated at four levels of soil salinity (0, 60, 120 and 180 mM) as factorial experiment in a completely randomized design with three replications at Yazd Agricultural and Natural Resources Research Center, during 2013. Twenty days after the first germination as salinity treatments were done gradually. Eight weeks after salt treatment, the sampling for biochemical traits (proline, total phenols, malondialdehyde, catalase and superoxide dismutase) from the youngest mature leaves were separated from each other and then shoot and root traits morphology (root and shoot dry weight) were measured. SAS data analysis was used to compare the means and the Duncan´s (P ≤ 0.5) test. Results and discussion The results showed that morphological traits such as shoot and root biomass, were mainly affected by severe salinity stress, but salinity stress (120 and 180 mM) had no significant effect on these traits. In this study, increased salinity stress increases the leaf proline and malondialdehyde content and reduced total phenolic in all accessions. The highest proline obtained in sensitive indigenous accessions (kermanshah) at severe salinity stress. Enzymes activity of superoxide dismutase and catalase increased in salinity resistant accession kermanshah than other accessions. Existence or poor performance of salinity tolerance or avoidance mechanisms in kermanshah accession possibly caused induction of oxidative stress and produced antioxidant enzymes. In terms of salinity, plant to reduce the effects of oxidative stress antioxidant enzymes such as superoxide dismutase and catalase activity increases. The activity of the enzyme superoxide dismutase and catalase negative correlation with leaf malondialdehyde (-0.88**,-0.91**) there. Also, a significant positive correlation (0.9**) between activity of catalase and superoxide dismutase indicates a close relationship between these two enzymes in removing free radicals. Conclusion Shoot and root biomass were mainly affected by high salt stress and accession Ardakan shoot biomass was highest, maybe the accessions to fight the salinity of sodium and chloride ions into the cell vacuole leaves the store. In this study, increase of salinity, proline and malondialdehyde increased in all accessions. Accession kermanshah were the most proline in extreme conditions of salinity, which indicates the ability of the accessions to accumulate proline, malondialdehyde and other organic solute to prevent oxidative stress and maintain inflammation plant cells. The effect of salinity stress, superoxide dismutase and catalase enzyme activity were sustained in the accession production of these enzymes, a sign of oxidative stress caused by salinity.
Fereshte Rezaee Nasab; Alireza Pazoki; Reza Monaem
Abstract
Introduction Today medicinal plants are an important part of the traditional medicine in many countries, they also have a special place and high value in new therapeutic approaches. Iran is one of the major habitats of many medicinal plants, one of these medicinal herbs, lavender with the scientific ...
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Introduction Today medicinal plants are an important part of the traditional medicine in many countries, they also have a special place and high value in new therapeutic approaches. Iran is one of the major habitats of many medicinal plants, one of these medicinal herbs, lavender with the scientific name (Lavendula officinalis L.) is an evergreen plant from Lamiaceae family. Lavender belongs to arid and semi-arid areas. It needs lots of light, warm weather and less humidity during growth. Under such conditions, the performance of the flower, essence, as well as the quality of the essence increases. Salinity is the presence of soluble salts and mineral elements in water and soil that will lead to the salt accumulation in the root area so that the plant will face difficulty absorbing enough water from the soil solution. Soil salinity is one of the most important factors limiting crop yields around the world, that this issue, particularly in arid and semi-arid areas is considered as one of the most fundamental problems of agricultural sector. Iran, with warm and dry climate is no exception to this issue. More than half of its arable lands (around 27 million hectares) is formed from salty soil and sodium. So in order to make the optimal use of these lands and saline water resources, a reformative important approach is to boost plant tolerance associated with higher production capacity. To deal with the stress, plants have a defense system with high efficiency which can destroy or neutralize free radicals. This defense system, includes enzymatic and non-enzymatic mechanisms. according to the above mentioned items, this study was done to investigate the effect of salicylic acid and Jasmonic acid on the soluble sugars, Proline, activity of antioxidant enzyme of lavender herb (Lavendula officinalis L.), in salinity tension situation to reduce the bad effects of tension. Materials and Methods To investigate the effect of Salicylic acid and Jasmonic acid solution on soluble sugar, Proline and antioxidant enzyme activity of lavender herb in salt tension situation, the pot experiments was done in 1393 in Azad Islamic University, Yadegar Imam Khomeini (RAH) branch of Ray city also the greenhouses that located in strict 4. The experiment was done through a factorial arrangement in a completely randomized basis with four replications. The experimental factors were included salt stress from salt (NaCl) in four levels (0, 25, 50 and 75 mM), Salicylic acid in two levels (0 and 0.7 mM), and Jasmunic acid in two levels (0 and 100 mM). Results and Discussion The results of the comparison of the salinity average simple effects showed that this factor caused an increase in soluble sugar, proline, activity of antioxidant enzymes such as Catalase, Superoxide dismutase, Peroxidase, Ascorbate peroxidase and Glutathione peroxidase. According to the research, the use of Salicylic acid, Jasmonic acid through increasing the activity of soluble sugar and proline, increased plant resistance in saline conditions. The results of the study also showed that only the interaction of the three attributes of treatments of the experiment on Peroxidase, Ascorbate peroxidase’s traits was significant. In this case, the highest Peroxidase activity (50/27 mg pr/min) and ascorbate peroxidase (24/12 mg pr/min), in salinity factor 75 mM and the absence of the two mentioned compounds was obtained. Conclusion According to the results of the experiment, it can be confirmed that following the use of Salicylic acid and Jasmonic acid under salt stress, proline and soluble sugars contents were increased and antioxidant enzyme activities were decreased. In other words, while using these two compounds, the lavender medicinal herb has used soluble sugar and Proline to cope with the salt stress.
Abouzar Asadi; Ali Reza Askary Kelestani; Rezagholi Mirfakhraii; Alireza Abasi; Mostafa Khodadadi
Abstract
Introduction Food productivity is declining due to the effect of different abiotic stresses. Stress is the result of abnormal physiological processes that influence by one or a combination of biological and environmental factors. Cold, salinity and drought are important among the other stresses. Three ...
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Introduction Food productivity is declining due to the effect of different abiotic stresses. Stress is the result of abnormal physiological processes that influence by one or a combination of biological and environmental factors. Cold, salinity and drought are important among the other stresses. Three types of cold stress has been identified that include: Frost, Freezing and Chilling Stress. The relationship between plant growth and climate change is a seemingly contradictory event. In fact, warming increases danger of cold stress. In the spring, at the same time of started wheat growth, it is increase its sensitivity to low temperatures and it damaged. This model of cold stress called rapidly falling temperatures in the spring or in short term called "chilling". Chilling stress reduced leaf expansion, wilting, chlorosis (yellowing of leaves) and may lead to necrosis (death of tissue) and strongly disturbed the reproductive development of plants. Low temperature stress limit the grain production in cold and ultra-cold climates and makes high damages in some years. Therefore produce resistant cultivars is necessary. Management of genetic resources, and knowledge of the genetic diversity are tow important principles of breeding projects. This study examines the genetic diversity of some of bread wheat cultivars for some physiological characteristics associated with chiling stress using multivariate statistical methods and compare these methods. Materials and methods This survey performed in 2013 at the Faculty of agriculture, Tarbiat Modares University. In this study an experiment with 20 varieties of wheat with four treated cold levels of stress (8 (control), +2, 0, -2 Celsius) in factorial arrangement in randomized completely design implemented. In early of reproductive stages (Zydaky code 50 to 68), the plant transferred to growth chamber under 14/10 hours and 16/8 °C day/night photoperiod. To impose stress, temperature reduced 2°C per one hours from 8 °C then the pots were placed for 2 h under stress in each of stress temperature levels (2, 0 and -2 °C). After stress, temperature up to 8 °C with ramp 2 °C per hours. Sampling was done after 24 h and then electrolyte leakage, chlorophyll (a, b, ab and cartenoids), proline and fructan, were assessed. Results and discussion The results of this study showed that the effects of interaction between gentopyes and chiling stress were significant at 1% level. Based on results of the cluster analysis twenty genotypes were classified into four groups in -2 celsius temperature and two groups in control temperature. The principal component and principal coordinate ,confirmed grouping created based on of cluster analysis. The principal component analysis decrease all treats in to 3 components in control (with cumulative of variance 80) and sever stress (with cumulative of variance 85). Also the principal coordinate analysis decrease all component to 3 components with cumulative variance 94.11 (for control) and 96.59 (for sever stress). Based on cluster analysis Pishgam and Aflak genotypes in control condition and Alvand and Sivand in -2°C had the maximum genetic distance. The minimum genetic distance was observed between Mv17 and Navid genotypes (in control condition) and Kaskojen and Pishgam (sever stress). Conclusions (1) Chiling stress detects the diversity amoung studied gentopyes; (2) In order to grouping of genotypes, cluster analysis provided more accurate grouping than principal component analysis and principal coordinate analysis ; (3) Alvand and Sivand cultivars can be use as potential parents to provide the necessary population in classical breeding programs, in order to detect of QTLs for chiling tolerance and also for marker assisted selecion.
Seyedeh Mahbobeh Mirmiran; Ahmad Nezami; Mohammad Kafi
Abstract
Introduction In tolerance to coldness researches, scholars are looking for exams which in addition to having easiness, velocity and enough validity, be repetitive as well and mean while the feasibility of controlling the thermal conditions be in it. Using different kinds of freezing exams in controlled ...
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Introduction In tolerance to coldness researches, scholars are looking for exams which in addition to having easiness, velocity and enough validity, be repetitive as well and mean while the feasibility of controlling the thermal conditions be in it. Using different kinds of freezing exams in controlled and artificial conditions have been suggested. Hence, damage evaluation via measuring the electrolyte leakage and determining the Lethal Temperature 50 According to the Electrolyte Leakage percentage (LT50el) is considered as a suitable and direct method for evaluating the amount of coldness damages by the researchers. Materials and method In order to evaluate freezing tolerance of fenugreek a factorial experiment in 2013-2014 year based on completely randomized design with three replications was conducted under controlled conditions in faculty of agriculture, Ferdowsi University of Mashhad. The investigated factors include sowing date in four levels (September 13, October 14, March 5, and April 3), ecotype in 10 levels (Azari, Ardestan, Long foot, Short foot, Shiraz, Shirvan, Mashhad, Neyshabur, Hamedan and Hendi) and freezing temperature in seven levels (control, 0, -3, -6, -9, -12, -15 0C). The potted plants grew and cold acclimation in outside conditions then the plants which were implanted in September and October, and the plants which were implanted in March and April , were transferred to the freezer thermo gradient to apply the cold temperature in the middle of December and in the middle of May respectively. After freezing, Percentage Electrolyte leakage (%EL) and Lethal Temperature 50 According to the Electrolyte Leakage percentage (LT50el) was determined. Survival percentage of them after freezing and 28 days growth was measured in the greenhouse. Results and Discussion Although in the all sowing dates the electrolyte leakage was constant up to the temperature of -6 0C and by more reduction in temperature, it had an increasing trend, but the leakage increase velocity in the sowing dates in the first decade of March war more than other dates. As in this sowing date by reducing the temperature from zero to -15 0C, the percentages of electrolyte leakage increased about 71 percent. In some ecotypes such as Shiraz and Hamedan by causing delay in sowing date from July to April the percentage of electrolyte leakage was increased. Although the electrolyte leakage percentage in all ecotypes in the second sowing date of fall and spring was reduced in compare to the first sowing date, the lowest and the highest reduction resulted from delay in sowing date belonged to Hamedan and Ardestan respectively. Although by temperature reduction the percentage of electrolyte leakage was increased in the all ecotypes, but this increase was more intense in the Hendi ecotype than other ones. In this ecotype by reducing the temperature from zero to -15 0C, the electrolyte leakage percentage increased 73 percent whereas in Neyshabur ecotype this increase was 53 percent. The percentage of electrolyte leakage from the Trigonella foenum-graecum ecotypes in each sowing date increased by temperature reduction. In the majority of ecotypes this increasing trend was witnessed from the -6 0C. In the all ecotypes, the October 14 sowing date in the majority of the studied temperatures had lower leakage percentage than other sowing date. According to the LT50el index, the sowing date of the first decade of October in ecotypes was lower in compare to other dates. In other words, earlier sowing date of ecotypes probably leads to increase in plants sensitivity to coldness. The highest and lowest tolerance to freezing, according to this index, belonged to Neyshabur and Azeri ecotypes respectively. Between Lethal Temperature 50 According to the Electrolyte Leakage percentage (LT50el) and survival (r=-0.536*) negative and significant correlation was witnessed which indicates that using this index in evaluating the damage of freezing tolerance in Trigonella foenum-graecum is possible. Conclusion Generally in this study in all of the ecotypes, reducing the temperature led to increase in the percentage of electrolyte leakage. This leakage increase slope in the majority of ecotypes began from -6 0C and in -15 0C was maximized. Delay in autumnal and spring sowing dates by affecting the plant growth stage cause increase in plants tolerance to freezing. In other words, the plants which were in advanced vegetative level in the exerting time of freezing temperatures had lower tolerance to freezing. Among the studied ecotypes, however, the Neyshabur and Azeri ecotypes had the highest and the lowest tolerance to freezing respectively considering the leakage amount and LT50el. Therefore, it seems that the sowing date of October is suitable for sowing Neyshabur, Mashhad, Shirvan and Short foot ecotypes which had lower leakage percentage and more suitable LT50el in compare with other ecotypes. However, more researches in evaluating the plant’s tolerance to freezing in real winter conditions and determining correlation relationships between the results in controlled situations and farm will be useful.
Ali Moshatati; Seyed Ataollah Siadat; AbdolMahdi Bakhshandeh; Mohammad Reza Jalal-Kamali
Abstract
Introduction Temperature is the most important determining factor in growth and development duration length of crops. Temperature increase result in faster growth and development and shorter life duration of plant. This is one of the main factors of yield loses in hot environments (Aggravel, 1991). Studies ...
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Introduction Temperature is the most important determining factor in growth and development duration length of crops. Temperature increase result in faster growth and development and shorter life duration of plant. This is one of the main factors of yield loses in hot environments (Aggravel, 1991). Studies showed that one centigrade increase in mean temperature of growth duration causes eight days (6 percent) decrease in vegetative growth phase, two days (five percent) decrease in filling period duration and 21 days (eight percent) decrease in life cycle duration of wheat (Koocheki and Hosseini, 2006). Modhej et al. (2007), planted six wheat cultivars (three bread wheat cultivars and three durum wheat cultivars) in two sowing dates (November 21 as optimum sowing date and January 20 as late sowing date) and reported that grain filling period of late sowing date confronted to terminal heat stress and resulted in significantly decrease in grain weight and grain yield. In this study, the most important aim is to study the effect of terminal heat stress on growth periods length, grain yield and its components and grain yield formation rate and its components in 20 spring bread wheat cultivars in Ahwaz condition. Materials and methods In order to study the effect of terminal heat stress on growth periods length, grain yield and its components and grain yield formation rate and its components in 20 spring bread wheat cultivars, a field experiment was conducted in a stripe block arrangement using a complete randomized block design (CRBD) with three replications in research field of Ramin Agriculture and Natural Resources University of Khouzestan (in 31º N, 48º E, 35 Km north-east of Ahwaz, and 20 m above the sea level) during two cropping seasons (2007-2008 and 2008-2009). Experimental factors were four sowing dates (06 Nov. (early), 06 Dec. (timely), 05 Jan. (late) and 04 Feb. (very late)) in vertical plots and 20 spring bread wheat cultivars (Atrak, Arvand1, S-80-18, Star, Inia66, Bolani, Bayat, Pishtaz, Chamran, Chenab70, Darab, Dez, Roshan, Shoeleh, Kavir, Maroon, Hamoon, Hirman and Vee/Nac) in horizontal plots. Results and discussion Results showed that year, sowing date, genotypes and sowing date× genotype had significant effect on measured traits. Mean comparisons revealed that with delay in sowing date and increase in mean temperatures of growing season, decreased the day from sowing to anthesis, day from anthesis to maturity, day from sowing to maturity, grain number in m2, thousand grain weight and grain yield that resulted to decrease in grain formation rate, grain filling rate and grain yield formation rate. Generally, Maroon and Shoeleh cultivars (early- lately maturity cultivars) with short period of sowing to anthesis and with long period of anthesis to maturity, had longer grain filling period. Conclusions Generally and according to these results could say that delay in sowing and increase in temperature of growth cycle duration resulted in confrontation of terminal phases of growth and development to high temperatures and occurrence the terminal heat stress. These stress decreased the day from sowing to anthesis, day from anthesis to maturity and day from sowing to maturity. These effects resulted in lower grain number in m2, thousand grain weight and grain yield. Finally, above decreases lead to lower grain formation rate, grain filling rate and grain yield formation rate.
Volume 11, Issue 1 , April 2018, Pages 210-210
