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In order to investigate the phonological characteristics of new hybrids of corn in drought tension, this experiment as a complete randomized block design in a strip-plot arrangement was done at the research field of University of Agriculture and Natural Resources of Ramin Khouzestan in 2010-2011. It included three levels of irrigation regime (irrigation cut-off in 8-leaf stage, irrigation cut-off in stage of male flower appearance and optimum irrigation) in longitudinal plots and 11 hybrids (07-101, 07-103, 07-107, PL710, PL711, PL706, PL774, AS71, Mobin, Karoon and S.C 704) in transversal plots with three replications. The results showed that irrigation cut-off in 8-leaf stage (vegetative stage) caused duration of vegetative growth to last longer, whereas it postponed starting of generative growth, so that the longest duration of vegetative growth was obtained for hybrid 07-107 in tension conditions in 8-leaf stage and the shortest duration happened to hybrid PL706 and in non-tension conditions. Duration of generative growth of different hybrids was influenced by the amount of water received by plant of course this change happened more intensely in drought tension treatment in stage of male flower appearance. The longest duration of generative growth was obtained for hybrid PL706 in optimum irrigation conditions and the shortest duration was obtained for hybrid AS71 in drought tension conditions in stage of male flower appearance. Duration of pollination of different hybrids was affected by the degree of plant access to water. The longest duration (11.17 days) of pollination was obtained for hybrid PL706 in non tension condition and the shortest duration was observed for 07-101, 07-103, AS71, PL710 and PL711 hybrids all the same in 3.67 days in irrigation cut-off conditions in stage of male flower appearance. The trend of the variations in duration of flowering indicated that this duration was longer for all hybrids in optimum irrigation conditions, whereas it was shorter in tension conditions in stage of male flower appearance and Interaction drought tension and hybrid on duration of flowering adaptation was significant.

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The effect of drought of the end of season on grain yield and quantitative characteristics of eleven promising lines of spring rapeseed, with Hyola 401 cultivar as control, were investigated as a randomized complete block design with three replications at two normal and irrigation cut tension conditions from the beginning of flowering in two years (2008-2010) at Safiabad Agricultural Research Center. After the combined analysis in the main effects of drought tension and lines, and their interaction, significant statistical differences was observed in grain yield average and other quantitative traits. Irrigation cut at the beginning of flowering reduced seed yield 25%, number of capsules per plant 14.4%, 1000-seed weight 13.6%, seed number per capsules 10% and oil content 6.5% in comparison to control treatment. The highest seed yield obtained on no tension conditions in Hyola 401 and L4 with 2537 and 2511 kg/ha, respectively and on tension conditions was in Hyola401 and L1 with 2025 and 1974 kg/ha, respectively. The comparison of means in two conditions of irrigation separately showed that the difference between lines in tension conditions was more than no tension conditions. Thus, the lines regarding the reaction of yield to tension have different genetic tolerance. So, using of lines with desirable genetic traits such as minimum reducing grain yield, yield components and oil percentage is appropriate in breeding programs. Totally, the lines L1, L4 and L11 are recommended as alternative to Hyola 401 cultivar.

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This experiment was conducted in order to investigate the effect of post anthesis drought tension on agronomical traits, biochemical characteristics and some physiological characteristics. The experiment was carried out in pot culture experiment as factorial experiment based on complete randomized blocks design in three replications in Campus of Agriculture and Natural Resources of Razi University, Kermanshah in 2011-12 cropping year. In this experiment, drought tension was considered at generative growth stage (from the anthesis stage until end of soil moisture growth stage, around 30 percent of field moisture) and different wheat genotypes consisted of Pishtaz, DN-11, Sivand and Marvdasht were investigated as the second factor. The results showed that drought tension after anthesis decreased grain yield by decreasing of 1000- grain weight. Under drought tension after anthesis, Marvdast and DN-11 genotypes had the lowest grain yield. The occurrence of drought tension significantly decreased soluble protein content. The activity of superoxide dismutase enzyme increased after anthesis in drought tension conditions. Catalase and peroxidase activity in the sensitive genotypes (Marvdast and DN-11) was less than the tolerant genotypes (Pishtaz and Sivand). It can be concluded that activating the enzymes defense system of catalase, peroxidase and superoxide dismutase antioxidants in wheat genotypes has had a major role in increasing tolerance to drought tension.

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In order to study the effect of drought tension effect at the end of season on grain yield and the assessment of lines tolerance to tension, this experiment was conducted in a randomized complete blocks design in the Agricultural Research station of Kheirabad Zanjan. In this experiment 14 genotypes of bread wheat selected from the breeding experiments of cereals sector of Zanjan Agricultural Research center were under irrigated and end seasonal drought tension in two separate experiments. Results of variance analysis showed that in the absence of tension conditions between genotypes for all traits of genotypes except biological yield there was significant difference at the probable level of one percent and biological yield at the probable level of five percent. Results of variance analysis in drought conditions showed that between all genotypes traits except grain yield at the probable level of one percent and regarding to grain yield trait at the probable level of five percent there was significant difference. Based on tolerance indices (STI, MP and GMP) genotypes 11, 6, 9 and 4 were more tolerant genotypes. Among the mentioned genotypes, genotype 11 which had the highest indices amount of STI=0/98, MP=4765/05 and GMP=4723/11 and has had the highest yield under drought tension conditions (Ys) (4134/26 kilogram per hectare), was selected as a high-yielding and tolerant genotype.

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Much of the lands under wheat in the world is in arid and semiarid regions. In these regions the water requirement of wheat in all development stages can not be fully met. This research was conducted in this regard and in order to investigate the effect of post anthesis water deficiency tension on quantity and quality of grain yield and some physiological characteristics of wheat different cultivars. This experiment was conducted in the potted form as three-factors factorial for physiological traits and two-factors for yield quantity and quality and based on randomized complete blocks design with three replications at Campus of Agriculture and Natural Resource of Kermanshah Razi University during 2011-12 cropping year. Three investigated factors included: 1) humidity treatment in two levels of non-tension (field capacity) and water deficiency tension from pollination stage till the end of growing season (30 percentage field capacity), 2) different wheat genotypes (Pishtaz, DN-11, Sivand and Marvdasht) and 3) sampling date in two levels including: 11 and 17 days after anthesis. The results showed that in tension and non-tension water deficit conditions Marvdasht cultivar had the lowest grain yield. Among the other investigated genotypes (in two humidity conditions), Pishtaz had the highest grain yield. The lowest grain yield drop in water deficit conditions compared to non-tension was relared to Pishtaz cultivar, as well. Applying water deficit tension caused significant reduction of chlorophyll a and b concentration, total chlorophyll and carotenoids, maximum quantum yield of photo system II, viability index and relative water content. Also, water deficit tension caused decreasing in starch content and total dry mater and increasing in fiber content and   grain protein of investigated genotypes.

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In order to investigate the effect of water deficit tension and zeolit application on the amount of damage biomarkers, relative content of leaf water, electrolytes leakage and chlorophyll of rapeseed (Brassica napus L.) Okapi cultivar, the present experiment was done as split plot based on based on randomized complete blocks design with four replications during fall 2010-11 at Islamic Azad University field research , Yadegar-e-Imam Khomein ^(RAH) Shahr-e-Rey Branch. Irrigation at three levels (irrigation based on 80, 130 and 180 millimeter evaporation from class A evaporation pan) as main plot, zeolite consumption in three levels (no consumption, 6 and 12 tons per hectare consumption) as sub-plot were considered. The results of experiment indicated that all traits tested were significantly different regarding to irrigation levels and zeolite application and the effect of experimented treatments interaction was significant only on electrolytes leakage and chlorophylls content. The mean comparison of main effect of irrigation demonstrated that applying irrigation based on 180 millimeter evaporation from class A evaporation pan, established the highest amount of  Malondialdehyde (2.54 nanomoll per milligram protein), Dihydroxyguanosin (17.60 nanomoll per milligram protein), Dityrosine (27.02 nanomoll per milligram Protein) and electrolytes leakage (1.55 millizimence per cm) and lowest relative leaf water content (0/61 percent) and total chlorophyll (4.32 milligram per liter). In severe drought tension conditions 180 millimeter, using 12 tons per hectare zeolit consumption by the improvement of plant moisture status led to prevent drought tension harm effect and reducing leakage electrolytes to 0.99 millizimence per cm  and chlorophyll a+b to 4.75 milligram per liter.

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About 60 percent of the lands under bean cultivation in the world are in areas face with water shortage during the growth season. In order to investigate the influence of deficit irrigation (supply of 100, 80 and 60 percent of crop water requirement) on pinto bean genotypes(Sadri, C.O.S.16, KS21193 (Koosha193), Taylor Line and KS21486) the present  experiment was conducted as split plots based on randomized complete block design at the research farm of Faculty of Agriculture of Shahrekord University during 2013-14. Results showed that reducing the amount of water used decreased succulence index and the amount of leaf water content of under investigated genotypes. In addition, canopy temperature increased due to reduction inthe amount of water irrigation. Stomatal conductance of both sides of all genotypes decreased due to reduction of the amount of using water.The highest grain yield in supply conditions of 100 and 80 percent of plant water requirement conditions, was obtained from C.O.S.16 (594.6 and 289.2 gram per meter square, respectively). In the supply conditions of 60 percent of water requirement conditions, KS21486 genotype allocated the highest grain yield (109.5 gram per meter square). There was a significant and inverse relationship between canopy temperature and grain yield in all the measured stages both before and after irrigation. Also, a positive and significant correlation between stomatal conductance bottom of leaves in  all stages of measurement before irrigation with grain yield was observed. It seems that stomatal conductance indices, canopy temperature and stomatal index are good indicators for determination the effect drought tension in pinto bean and through the mentioned traits, identification of drought tolerant and sensitive genotypes would be easy.

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In order to investigate the grain yield, one hundred grain weight, stress tolerance index (STI), concentration of chlorophyll (a+b), the amount of proline and soluble sugar of maize hybrids in response to drought tension, the present experiment was carried out as split plots based on randomized complete blocks design with four replications on the farm of Moghan Research Station, during 2010 and 2011. The main factor irrigation at two levels (normal irrigation and irrigation cut at grain filling stage) and sub factor were maize hybrids (Single Cross700, Single Cross KLM and Single Cross704). Combined analysis of data showed that drought tension had a significant effect on all traits. The drought tension reduced 32.67 percent the amount of grain yield, 18.59 percent one-hundred grain weight and 15.71 percent concentration of chlorophyll (a+b); but, drought tension increased 88.77 percent the amount of proline and 45.51 percent of soluble sugar content. The amount of STI in related to Single Cross 704, Single Cross KLM and Single Cross 700 were 1.01, 0.70 and 0.50, respectively. Single Cross 704 displayed the maximum amount of grain yield, one hundred grain weight, concentration of chlorophyll (a+b), the amount of proline and the minimum amount of soluble sugar was related to Single Cross 704. According to the obtaining results, Single Cross 704, Single Cross KLM and Single Cross 700 were studied and identified as tolerant, semi-tolerant and sensitive to drought tension, respectively.

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In order to investigate the effect of different sources of organic and chemical fertilizers on some physiological parameters of different rice cultivars in drought tension conditions, an experiment was conducted as split factorial in a randomized complete blocks design with three replications at research farm, located in Sari in 2016. Three levels of tension included drought tension at early tillering stage, drought tension at full heading stage and control (no tension) were considered as the main factor and four fertilizer sources of vermicompost, Azolla compost, humic acid and chemical fertilizer of N.P.K and two cultivars of Shiroudi and Tarom Mahali as factorial as the  sub factor. The results showed that there was a statistically significant difference between Tarom Mahali and Shiroodi cultivars in terms of yield at drought tension levels and different fertilizer sources. The highest paddy yield for Shiroudi and Tarom Mahali cultivars (equals to 6577 and 3776 kilogram per hectare, respectively) was obtained under common irrigation conditions and with the application of tension, the rate of yields decreased, especially with the application of drought tension in the clustering stage, when the yield of Shiroodi and Tarom Mahali cultivars decreased by about 17.6 and 2.9 ercent, respectively. The application of humic acid, Azola compost and vermicompost resulted in 17.3, 13.7 and 8.8 percent increase in grain yield for Shiroudi cultivar and 9.7, 3.8 and 2.6 percent increase in yield for Tarom Mahali under drought tension at tillering stage, respectively, compared to N.P.K chemical fertilizer. The highest amount of total and reducing sugar (147.3 and 4.289 milligram per gram, respectively) was obtained under drought tension conditions at early tillering stage with using the humic acid for Shiroudi cultivar. Therefore, according to the results of the present research, the application of humic acid is suitable for achieving the maximum grain yield of studied rice cultivars under drought tension conditions.

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In order to investigate the effect of methanol on the activity of antioxidant enzymes, some compatible osmolytes and biochemical traits of wheat under cut off irrigation conditions, the present experiment as factorial was conducted based on randomized complete blocks design with three replications at the research farm of Faculty of Agriculture and Natural Resources of University of Mohaghegh Ardabili, during 2015-2016 cropping year. The investigated factors were included irrigation levels (full irrigation as control, cut off irrigation in 50 percent of spike stage and cut off irrigation in 50 percent of the booting stage (pregnancy) as mild and sever water restriction, respectively; according to codes 55 and 43 of the BBCH scale) and methanol foliar application at four levels (foliar application with water as control and foliar application 10, 20 and 30 percent by volume of methanol). The results showed that foliar application of 30 percent by volume of methanol under full irrigation conditions increased 42.83, 36.01, 29.69, 57.93 and 49.98 percent of chlorophyll b content, total chlorophyll, carotenoids, protein percentage and grain yield and decreased hydrogen peroxide and malondialdehyde content 75.58 and 63.77 percent, respectively; in comparison with non-foliar application under cut off irrigation at the booting stage. Foliar application of 30 percent by volume of methanol under cut off irrigation conditions in booting stage increased proline and soluble sugars content (125.42 and 91.93 percent, respectively) in comparison with non-foliar application of methanol under full irrigation conditions. Also, foliar application of 30 percent by volume of methanol under full irrigation conditions decreased the activity of antioxidant enzymes (catalase, peroxidase and polyphenol oxidase). It seems that foliar application of 30 percent by volume of methanol can increase grain yield of wheat under cut off irrigation conditions due to improving biochemical traits.

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Dehydration and deficiency of nitrogen fertilizer are important factors in reducing the quantitative and qualitative yield of wheat. The use of appropriate cultivars and some agricultural operations can help reduce the damage of these factors. In order to investigate the effect of irrigation cut and different amonts of nitrogen fertilizer on some quantitative, qualitative characteristics and redistribution rate of photosynthetic materials stored in durum wheat plant, the present experiment was carried out in a statistical form of split -split plots in a randomized complete blocks design in three replications in Ramhormoz during 2013-14 cropping year. Experimental factors include three levels of irrigation cut in the spike stage, at the beginning of the seeding stage and full irrigation in the main plots, four levels of nitrogen (zero, 60, 120 and 180 kilogram per hectare of pure nitrogen from the urea source) in the subplots and two durum wheat cultivars Yavaros and Behrang were in the sub-sub plots. The results showed that irrigation cut and nitrogen fertilizer content treatments had a significant effect on quantitative, qualitative and redistribution rate traits of photosynthetic materials and there was also a significant difference between investigated wheat cultivars in terms of growth response to irrigation cut and nitrogen fertilizer content. The highest grain yield (3587.3587 kilogram per hectare), harvesting index and redistribution of total shoot (0.96 gram per plant) in Behrang cultivar with consumption of 180 kilogram per hectare of nitrogen fertilizer in full irrigation was obtained. In general, it can be said that reducing the effects of irrigation cut by balanced selection of nitrogen fertilizer and the correct choice of cultivar (Yavarus) can be a good opportunity to make optimal use of low irrigation techniques to combat water shortage.

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In order to investigate the effect of drought tension, nitrogen supply source and planting density on agronomic and physiological characteristics of sunflower cultivar Haissan in the north of Golestan province, an experiment was conducted in 2015 and 2016. The present research was performed in the form of split- split plots in randomized complete blocks design with three replications and 27 treatments. The main factor included drought treatment with three rainfed levels, one irrigation stage (cultivation stage) and three irrigation stages (cultivation, flowering, grain filling stages). The sub-factor included three levels of nitrogen supply (100 percent urea, 50 percent nitroxin and 100 percent nitroxin) and plant density as a sub-sub-treatment had three levels of 50, 75 and 100 thousand plants per hectare that were randomly placed in main and sub-plots and sub-sub-plots. The results showed that the effect of drought tension, nitrogen supply source and plant density on plant height, seed diameter, number of seeds, one-thousand grain, oil percentage, harvest index, biological yield and economic yield were significant at one percent probability level. The highest plant height, head diameter, number of seeds per head, one-thousand grain weight, oil percentage, harvest index, biological yield and economic yield were obtained in the treatment of three irrigation stages. Application of treatment (50 percent nitroxin and 50 percent urea) as nitrogen supply sources improved all traits. Based on the obtained results of the present research, three stages of irrigation and application of 50 percent nitroxin and 50 percent urea as a source of nitrogen supply and increasing plant density are recommended for proper production and yield.

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Drought Tension and nitrogen fertilizer are among the most important issues that researchers usually consider investigating the physiological yield and yield of new crops. The present research was conducted in the form of a statistical design of randomized complete blocks in the form of split plots with three irrigation levels in the main plots, including no drought tension or 60 percnt evaporation from Class A evaporation pan, medium tension or 90 percent evaporation from Class A evaporation pan and severe tension or 120 percent evaporation from Class A evaporation pan and six levels of nitrogen fertilizer including non-use of nitrogen fertilizer and values of 50, 75, 100, 125, 150 kilogram of nitrogen from urea source in subplot with three repetitions in Dare Shahr in 2019. The results of comparing the mean interaction of drought tension and nitrogen fertilizer treatments in grain nitrogen showed that in the absence of drought tension and application of 150 kilogram per hectare nitrogen fertilizer, the highest grain nitrogen was 3.53 percent and the lowest in severe drought tension and lack of nitrogen fertilizer application was 1.423 percent. Also, in all three levels of tension, the lowest and highest grain nitrogen was observed in non-consumption (control) and 150 kilogram nitrogen fertilizer, respectively. Comparison of the mean interaction of drought tension and nitrogen fertilizer treatments in grain yield showed that in the absence of drought tension and application of 150 kilogram per hectare nitrogen fertilizer, the highest grain yield was 2519.3 kilogram per hectare and the lowest was in severe drought tension and non-application of nitrogen fertilizer at the rate of 941.3 kilogram per hectare was obtained. Also, in all three levels of tension, the lowest and highest grain yield was observed in the non-consumption treatment (control) and 150 kilogram per hectare of nitrogen fertilizer, respectively. Due to the improvement of quinoa yield components by increasing the amount of nitrogen consumption and obtaining more grain yield, especially in water availability conditions, the results indicate high quinoa fertilizer.