جستجوی مقالات مرتبط با کلیدواژه « drought » در نشریات گروه « زراعت »

Barley is highly variable in adaptation to marginal environments. The main objective of barley breeding programs has been on improving yield by developing new cultivars with high grain yield and quality characteristics for different climates. Ansar is a new high yielding and drought tolerant cultivar of barley with facultative growth habit. It was released in the year 2013 for rainfed cold areas of Iran. Ansar originated from a cross Yea168.4/Yea605.5//Yea206-4A-3 (a high yielding line received from ICARDA). Based on regional yield trials, the average graind yield of Ansar was 3025 kgha-1, which was 55 kg higher than Sahand (2970 kgha-1). In comparison with Sahand (check), Ansar had 1-2 days early maturity, 4-6 cm taller stem, 1-2 g higher TKW. In onfarm trials, Ansar had 34, 12, 11% more grain yield than Sahand in Miyaneh, Oshnaviyeh and Piranshar regions, respectively. Ansar is tolerant to cold, drought, grain shedding, lodging, two-rowed variety with 73 cm plant height. Ansar is resistance to leaf strip, scald and powdery mildew and rust. It can be concluded that Ansar is not only a high-yielder, possesses better quality traits and tolerant/resistant to all diseases, but is also best suited in cold rainfed areas of Iran.Barley is highly variable in adaptation to marginal environments. The main objective of barley breeding programs has been on improving yield by developing new cultivars with high grain yield and quality characteristics for different climates. Ansar is a new high yielding and drought tolerant cultivar of barley with facultative growth habit. It was released in the year 2013 for rainfed cold areas of Iran. Ansar originated from a cross Yea168.4/Yea605.5//Yea206-4A-3 (a high yielding line received from ICARDA). Based on regional yield trials, the average graind yield of Ansar was 3025 kgha-1, which was 55 kg higher than Sahand (2970 kgha-1). In comparison with Sahand (check), Ansar had 1-2 days early maturity, 4-6 cm taller stem, 1-2 g higher TKW. In onfarm trials, Ansar had 34, 12, 11% more grain yield than Sahand in Miyaneh, Oshnaviyeh and Piranshar regions, respectively. Ansar is tolerant to cold, drought, grain shedding, lodging, two-rowed variety with 73 cm plant height. Ansar is resistance to leaf strip, scald and powdery mildew and rust. It can be concluded that Ansar is not only a high-yielder, possesses better quality traits and tolerant/resistant to all diseases, but is also best suited in cold rainfed areas of Iran.

In order to produce varieties of barley that tolerate drought and cold, Artan variety was entered into internal tests of the cold and temperate cold stations of the Dryland Agriculture Research Institute through the international center of ICARDA in the form of the of segregating populations (F3 generation) in 1997-98. Genetic purity was achieved by the modified bulk method. Then, during several years, it was evaluated in Maragheh, Shirvan, Ghamlo, Sararoud, Zanjan, Urmia and Ardabil stations in yield trials and yield stability experiment. The Artan variety with an average seed yield of 2.142 Kgha-1 had 11% higher seed yield than the Abidar check variety. Artan had relatively early maturity, height and high thousand-seed weight. Artan variety has general adaptability and good yield stability, facultative growth habit, resistance to seed shattering, tolerance to cold and drought, relative early maturity, high plant height (83 cm) and high thousand-seed weight (42 gr). It has also good level of resistant to yellow rust and brown rust diseases of barley. Artan variety was selected and released as a new cultivar due to its high yield and favorable agronomic characteristics for planting in the cold and moderately cold regions in rainfed areas of the country.

Selection of soybean cultivars that have a higher grain yield under water deficit conditions, reduces the damage to soybean producers.

The response of soybean genotypes to water deficit stress was investigated in terms of agricultural characteristics and grain yield in Karaj (Iran), during two years. The experiment was carried out as a split plot based on randomized complete block design in three replications, with three irrigation levels (control, mild stress, and severe stress)  based on 50, 100, and 150 mm evaporation from a  Class A evaporation pan as the main plot and 10 soybean genotypes as the sub-plot.

The results showed that mild and severe stress caused the node number and inter-node to decrease in comparison with control irrigation. Under control irrigation, the highest grain yield (2585 kg/ha) was obtained from the early-maturing Saba cultivar, with the highest seed number per unit area. The early-maturing genotypes had the highest grain yield under control irrigation, and their grain yield decreased significantly with increasing stress intensity. The grain yield of the Saba cultivar reduced under mild and severe stress by 32 and 59% compared to control irrigation, respectively. Under stress conditions, the late-maturing genotypes had the highest grain yield and water deficit stress caused a slight decrease in their grain yield. Under mild and severe stress, the late-maturing Williams×A3935 line had the highest grain yield and protein yield, respectively.

Under control irrigation, the Saba cultivar, and under stress conditions (mild and severe) the Williams×A3935 line is recommended in Karaj and similar climates (moderately cold region).

 Drought is one of the most important global threats to food production, in addition to that, climate change and the increase in the global population also widen the dimensions of this problem. One of the ways to solve this problem is to create new cultivars with greater tolerance to drought stress. Wheat has been one of the most important sources of human food all over the world and it is used in various food products and processing industries. Wheat together with rice and corn provide more than 60% of calories and protein needed for human nutrition. In areas like Iran, where most of the rain occurs in winter and early spring, wheat will face water shortage and drought stress at the end of the growing season. In crops, one of the effective methods that can minimize the effect of this phenomenon in combination with other methods of water deficit management is the use of high-yielding and drought-tolerant cultivars. Despite the numerous scientific sources published in this field, there are still many gaps in these studies, so studying the effects of drought stress is always a research priority. Ilam province, as one of the irrigated wheat production areas, suffers from the lack of cultivars that are resistant or tolerant to low irrigation conditions, so investigating the response of different wheat genotypes in low irrigation conditions as low input production systems is very important and is addressed in this study. 

In order to evaluate some bread wheat genotypes under normal and drought stress co ditions, 36 wheat genotypes were evaluated in the form of a randomized complete block design in three replicates in the crop year of 2019-2019 in Darehshahr city located in Ilam province. The examined traits include spike length, spike number per plant, spike length, peduncle length, sub-peduncle axis, flag leaf length, flag leaf width, number of stem nodes, plant height, number of spikes per plant, number of seeds per spike, number of seeds per plant. plant, number of tillers, hundred seed weight, single plant seed weight and seed yield. Based on performance under stress (Yp) and normal (Ys), drought tolerance indices such as average productivity tolerance index, harmonic mean, geometric meanproductivity (GMP), stress sensitivity index, stress tolerance index, performance stability index (YSI) and Relative Stability Index (RSI) and Performance Index (YI) were calculated. The mean comparison test was performed using Duncan's method and using R software. Simple correlation (Pearson), decomposition into components, decomposition into factors were also performed between the tested traits. SAS 9.1 statistical software was used for statistical analysis of traits. 

The results of the analysis of variance in drought and normal stress conditions showed that there was a significant difference between genotypes in all traits at the probability level of 1%. The most important significant correlation coefficient in both conditions between seed yield was related to the seed weight of a single plant and the number of seeds per plant. Considering the high and significant correlation of grain yield under stress and non-stress conditions with drought tolerance indices, higher productivity indices, geometric mean productivity (GMP), geometric mean  and stress tolerance index  as the best indicators. were chosen. It seems that in order to evaluate stress tolerance, the selection of genotypes should be based on several indicators. Factor analysis at the drougth stress condition indicated that the two first factors expalined a total of 97. 57% of the variance. The first factor was called the performance stability factor and the second factor was named theStability Factor. The biplot diagram also showed that the genotypes of no. 13 and 47 were placed in the vicinity of the ranges related to drought resistance indices (STI, MP, GMP, and HM) and were introduced as superior genotypes. 

According to the data obtained from analysis of variance in both normal and drought stress conditions, the genotypes were significant in terms of all traits. The significance of the studied traits indicates the existence of diversity between genotypes in terms of the studied traits, and some of these traits can be used to evaluate stress tolerance. The best genotypes had the best averages for peduncle length of genotype 33, for the number of seeds per plant of genotype 5, for seed weight of a single plant and seed yield of genotype 1. The heat map shows the relationship between drought tolerance based on different yield and drought stress toleranceindices. Considering the high and significant correlation of grain yield under stress and non-stress conditions with drought tolerance indices, average productivity indices, GMP, geometric mean and stress tolerance index were selected as the best indices that are able to distinguish tolerant genotypes from other Screen the genotypes. The yield index (YI) had the highest correlation coefficient with grain yield under stress conditions. Based on biplot results, genotypes No. 13 and 47 were the most tolerant genotypes under drought stress conditions more than other genotypes and were introduced as superior genotypes.

This study aimed to investigate the response of four ecotypes of milk thistle from Isfahan, Kohgiluyeh va Boyer Ahmad, Khuzestan-Omidiyeh, and Hungary to three irrigation regimes (irrigation after 40%, 60%, and 80% maximum allowable depletion of available soil water (evaluated in 2020-2021 under five different planting dates (September 27th, October 17th, November 6th, November 26th, and March 10th) at the research farm of Isfahan University of Technology in Iran. The experiment was conducted as a combined analysis of a split-plot based on randomized complete block design with three replications. The results showed that the highest and the lowest grain yield and shoot dry weight of milk thistle plants were obtained under the October 17th and March 10th planting dates, respectively. Water deficit at both levels decreased grain yield, shoot dry weight, number of flowers per plant, plant height, flowering degree-days, and physiological maturity degree-days, but increased grain and shoot water use efficiencies. The "Kohgiluyeh and Boyer Ahmad" ecotype exhibited the highest seed yield, shoot dry weight, seed/shoot water use efficiency, and harvest index, making it a promising candidate for breeding programs aimed at creating adaptive cultivars of the milk thistle plant. Based on the study's findings, it can be concluded that milk thistle should be planted in the fall season from late September to mid-November under similar climate conditions.

Drought is one of the most important non-living stresses that has an adverse effect on crop production and their quality and leads to osmotic, ionic, and nutritional limitations as well as growth delay, metabolic disorders and oxidative stress in plants. Iran has a dry and semi-arid climate and the occurrence of drought stress during the growth period of plants is inevitable. Presently, the production of legumes in the country is mostly under rainfed conditions and drought stress is one of the main factors reducing the yield of legumes. Mung bean is a small grain of valuable legume. Evaluation of the performance of different cultivars is considered a starting point in identifying drought-resistant cultivars. Cycocel is one of the most important growth retarders for tampering with growth and performance. Therefore, the present study was conducted to investigate the effect of foliar application of cycocel on quantitative traits of mung bean (Vigna radiata) genotypes under water deficit conditions.

In order to investigate the effect of foliar application with cycocel and water requirements on quantitative traits of mung bean (Vigna radiata) genotypes, experiental desing of split-split plot based on a randomized complete block design with three replications in research farm of the Ferdowsi University of Mashhad. Experimental factors included 3 levels of drought (non-stress, mild stress, and severe stress), 3 levels of cycocel foliar spraying (0, 400, and 800 mg/L), and 2 levels of mung bean cultivars (Hendi landrace and Zarbakhsh). Statistical analysis was performed using SAS 9.4 and comparing the means was based on the LSD method at a 5% probability level. 

The experimental results showed that the effect of drought stress, cycocel, genotype, and the interaction of drought stress and cycocel as well as drought stress and genotype on the number of pods per plant were significant. The results showed that drought stress reduced the number of pods in the plant and cycocel increased it. The number of pods in the plant of the Hendi landrace genotype decreased more than that of the Zarbakhsh genotype due to drought stress. Also, drought stress, cycocel, genotype, and the interaction of drought stress and cycocel as well as drought stress and genotype on the number of seeds in the pod, were significant. The results showed that cycocel increased the number of seeds per pod, while drought stress decreased the number of pods per plant. It was also found that at all levels of drought stress, the Zarbakhsh genotype had more seeds in pods than the Hendi landrace genotype. Drought stress, cycocel, genotype, and the interaction of drought stress and cycocel as well as drought stress and genotype had a significant effect on the 1000-seed weight. The results showed that the 1000-seed weight increased due to the application of cycocel, while drought stress decreased this trait. In addition, it was observed that the 1000-seed weight of the Hendi landrace genotype decreased more than the Zarbakhsh genotype due to drought stress. Drought stress, cycocel, genotype, and interaction between drought stress and cycocel had a significant effect on grain yield. The results showed that the grain yield in the Zarbakhsh genotype was significantly higher than in the Hendi landrace genotype. It was also observed that drought stress decreased and the application of cycocel increased grain yield. Drought stress, cycocel, and genotype had a significant effect on biological performance. Drought stress caused a significant decrease in biological yield. The use of cycocel increased the biological performance and increasing the concentration of this substance increased the biological performance. The results of variance analysis of data showed that the effect of drought stress, cycocel, genotype, and the interaction of drought stress and cycocel, drought stress and genotype as well as cycocel and genotype on harvest index were significant. In addition, it was observed that the harvest index of the Hendi landrace genotype decreased more than the Zarbakhsh genotype due to drought stress.

According to the results of this study in the presence of drought stress, it showed a decrease in yield and its components. Among the studied mung bean cultivars, the Zarbakhsh cultivar showed superiority in tolerance to water shortage conditions compared to other cultivars. The use of cycocel reduced the negative effects of drought stress on the plant. It appeared that the use of cycocel under drought stress conditions improved the plant better plants performance.

Corn is an important crop that is cultivated in many parts of the world. One of the major factors limiting the plant growth is lack of water, which reduces plant growth and survival in arid and semi-arid areas. For this purpose, evaluation of the effect of drought stress on plant cultivars and identification of the tolerant genotype is of particular importance.

In this research, nine corn hybrids (including three promising hybrids H1 (SC01; TS01×MS02), H2 (KLM77021/4-1-2-1-2-4-1× K47/3), and H3 (K47/2-2-1-4-2-1-1-1× MO17) and six commercial H4 (NS640), H5 (SC703), H6 (SC704), H7 (SC720), and H9 (SC715) grain corn hybrids as late and medium maturity groups) were planted in split plots in the form of a complete random block design in three replicates at Research Unit of Moghan Agro-Industry and Livestock Company, Ardabil in spring and summer 2022. The main plots include two levels of normal irrigation (10 times of atmospheric and stack irrigation according to the region's custom) and drought stress (interruption of irrigation during the flowering and seed filling stages: eight times of atmospheric and stack irrigation so that the interruption of irrigation at the end of flowering continued to grain filling for 18 days) and the sub-plots included six varieties and three hybrids of corn. In both irrigation conditions, yield and seed yield components were evaluated. To identify the tolerant genotype based on grain yield under stress and normal conditions, stress tolerance indices (STI), stress sensitivity (SSI), tolerance (TOL), mean productivity index (MP) and geometric mean yield (GMP) were calculated. Correlation and grouping was performed based on tolerance indices of drought stress in different corn hybrids.

Dehydration stress significantly reduced the yield and yield components of corn cultivars. The H7 (SC703) and H6 (SC704) hybrids were the ones with the highest plant height, hundred seed weight, number of seed rows in cob, and number of seeds in each cob row. Further, the hybrid H1 (SC01), H6 (SC704), H7 (SC703) and H3 (K47/2-2-1-4-2-1-1-1× MO17) have the highest seed yield in both conditions of normal stress and dehydration. The correlation between grain yield and grain yield components was significant and positive. The data obtained from the evaluation of drought tolerance indices showed that there was a significant difference between different corn hybrids. As the hybrid H6 (SC704) and promising hybrid H1 (SC01) allocated the highest MP, GMP and STI, and the promising hybrid H3 (K47/2-2-1-4-2-1-1-1× MO17) showed the highest SSI value. Correlation analysis between drought tolerance indices also showed a significant positive relationship between STI, SSI, TOL, MP and GMP. The cluster analysis of the studied corn hybrids based on drought tolerance indices divided the corn hybrids into three separate groups, such that the hybrids H1 (SC01), H3 (K47/2-2-1-4-2-1-1-1× MO17), H6 (SC704) and H7 (SC703) were classified as drought tolerant hybrids within the same group.

It seems that by simultaneous trait evaluation of the grain yield and grain yield components along with drought tolerance indices, it is possible to identify the genotype with high grain yield under water deficit stress. The information acquired by the study might be applied in the future remedial programs.

To investigate the effect of different levels of Mycort fungus, nitrogen fertilizer and cytokinin hormone on yield and yield components of wheat, an experiment was conducted in 2018-19 crop year. The experimental design was a factorial based on randomized complete block with three replications. The first factor was organic fertilizer of mycorrhizal fungus (2, 4 and 6 kg/100 kg seeds), the second factor was nitrogen fertilizer (zero, 25 and 50 kg/ha) and the third factor was cytokinin foliar application (control, foliar application at flowering and grain filling). The results of mean comparisons showed that levels of 25 and 50 kg/ha of nitrogen fertilizer increased the number of grains compared to the control treatment by 44.23 and 32.69%, respectively.resultsshowed that inoculation with 2 and 4 kg/100 kg of seeds along with the application of 25 kg / ha of nitrogen had the highest spike length and number of fertile spikes. The highest number of fertile spikes, number of grains per spike, 1000-kernal weight, grain yield and harvest index were assigned to seed inoculation treatment with 4 kg of mycorta and cytokinin foliar application at grainclosure stage. Also, foliar application of cytokinin in the graining stage along with the application of 25 kg / ha of nitrogenfertilizer had the highest number of spikes, 1000-kernal weight, biological yield and grain yield.

Drought stress is one of the most important factors that reduce the yield of crops in arid and semi-arid regions, including the climatic conditions of Iran. In the conditions of drought stress, one of the solutions to reduce the negative effects caused by drought stress and as a result increase water absorption is the development of roots through the use of biological fertilizers. Therefore, the present study was conducted to investigate the effect of drought stress and the application of nitrogen and phosphorus biofertilizers on the yield and some physiological characteristics as well as the content of photosynthetic pigments of cotton.

The experiment was conducted as a split plot with a randomized complete block design in three replications. In this research, irrigation levels include normal irrigation during the growth period as a control (60 mm evaporation from the evaporation pan), medium drought stress during the growth period (90 mm evaporation from the evaporation pan) and severe drought stress during the period. growth (120 mm of evaporation from the evaporation pan) as the main factor and 4 biofertilizer treatments, including no use of biofertilizer (control), Aztobacter biofertilizer, biophosphorus biofertilizer, and the combination of Aztobacter biofertilizers and biophosphorus as secondary factors.

The results showed that the yield, physiological characteristics and content of photosynthetic pigments were affected by the experimental treatments. Drought stress led to a decrease in plant height, yield, chlorophyll a, chlorophyll b, total chlorophyll and carotenoid. Drought stress increased the content of soluble sugars and proline, and although it reduced the relative content of leaf water and cell membrane stability, the application of biofertilizers improved them. The highest proline content of 3.63 mg/g fresh weight of leaves was obtained in the treatment of simultaneous application of biofertilizers Aztobacter and biophosphorus and at the level of drought stress treatment. The highest total chlorophyll content was obtained in the control treatment and the combined use of biophosphorus and azotobacter fertilizers at the rate of 3.75 mg/kg. The results showed the negative effect of drought stress on rice yield, so that in the control treatment, rice yield was 3536 kg per hectare, while in medium and severe drought stress treatments, rice yield was 2550 and 1495 kg per hectare, respectively. Also, the simultaneous application of biophosphorus and azotobacter fertilizers with their synergistic effect led to a further increase in rice yield up to 2722 kg/ha.

In general, the results showed that drought stress led to a decrease in cotton photosynthetic pigments, relative

Drought stress is one of the most important factors affecting crop yield especially in irrigated agriculture in arid and semiarid regions. Application of some stress modulators (vermicompost, mycorrhiza, putrescine and zinc nanooxide) increases growth, yield and the resistance of plants against various environmental stresses such as drought. However, the effect of these compounds alone has been investigated on modulating the effects of stress, there are fewer reports about their interaction effects. In this experiment, the interaction effects of organic, biological and mineral fertilizers and stress modulators were investigated on the improvement of current photosynthesis, dry matter remobilization process, grain filling components and grain yield of barley under water deficit conditions.

To investigate the interaction effects of some stress modulators (vermicompost, mycorrhiza, zinc nanooxide and putrescine) on the contribution of dry matter remobilization and grain filling components of barley under water deficit stress conditions, a factorial experiment in randomized complete block design with three replications was conducted in research greenhouse of Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran, in 2022. The experimental factors were included irrigation in three levels (full irrigation as control, irrigation withholding at 50% of the heading and 50% of the booting stages, equal to codes 55 and 43 of BBCH scale, as moderate and severe water limitation, respectively), application of biofertilizer, and organic and inorganic fertilizers in four levels (no application of fertilizers as control, application of vermicompost, application of mycorrhiza, combined application of vermicompost and mycorrhiza), and foliar application of putrescine and zinc nanooxide in four levels (foliar application of water as control, foliar application of 0.4 g.L-1 Zn nanooxide, foliar application of 0.8 mM putrescine, combined foliar application of Zn nanooxide and putrescine). Mycorrhiza fungus (mosseae species) was purchased from Zist Fanavar Turan company and according to copany’s protocol, 10 g per kg soil was used. Vermicompost was purchased from Gilda company and according to copany’s protocol, 50 g per kg soil was used. Zinc nanooxide production of China, with an average particle size of less than 30 nm, a specific surface of more than 30 m2.g-1, a Zn content of about 65.21% and a purity of 99%, was purchased from Jahan Kimia company, Urmia, Iran. The barley variety used in the experiment was Nobahar variety, which was cultivated with a plant density of 400 seeds per m2.

The results showed that the combined application of stress modulators (vermicompost, mycorrhizal, Zn nanooxide and putrescine) under irrigation withholding at booting stage conditions decreased dry matter remobilization from shoot and stem (22.32% and 25.65%, respectively) and their contribution in grain yield (52.92% and 56.95%, respectively) compared to the no application of biofertilizers and no foliar application of putrescine and Zn. In contrast, application of stress modulators under irrigation withholding in booting stage conditions increased total chlorophyll (24.91%), current photosynthesis (62.57%), contribution of current photosynthesis in grain yield (30.54%), grain filling rate (6.62%), grain filling period (18.06%), effective grain filling period (27.67%) and grain yield (25.18%) compared to the no application of biofertilizers and no foliar application of putrescine and Zn.

The findings of the current experiment showed that the application of stress modulators (vermicompost, mycorrhizal, Zn nanooxide and putrescine) can increase grain yield of barley under water limitation conditions by improving the current photosynthesis and grain filling components.

Barley (Hordeum vulgare L.) It is one of the most important grains and belongs to the genus of wheat. It is cultivated in more than one hundred countries of the world as a profitable crop. Barley is mostly used for grain production, for animal feed and fermentation industries. Among the grains, Barley had the highest production after wheat, rice and corn and accounts for nearly 91% of the world's grain production. In order to investigate the effects of urea foliar application on some physiological and agronomic characteristics of three barley cultivars under normal irrigation conditions and drought stress at the end of the season, a factorial experiment in the form of a randomized complete block design with three replications, during two years of cultivation 2017-2018 and 2018-2019 was carried out in the research farms of the Agricultural Research and Training Center of East Azerbaijan Province.

This study is a two separate experiment with optimal irrigation and drought stress at the end of the season was done with similar plans. Irrigation was stopped at the stage of spike emergence. Urea foliar application levels include non-foliar application and once foliar application after spiking was determined as the first factor and barley cultivars as the second factor. Barley cultivars included Mahtab, Jolgeh and Makuei. Measured traits included; Grain yield, 1000-seed weight, flag-leaf area, flag-leaf chlorophyll content and flag-leaf proline.

Drought stress reduces the value of all traits except flag-leaf proline and increased flag-leaf proline content in all cultivars. However, urea foliar application was able to mitigate the adverse effects of water stress. For the trait of grain yield, Mahtab cultivar with 4710.4 kg/ha at the control level and 5496.41 kg/ha at the level of urea foliar application, had the highest grain yield among cultivars under drought stress conditions. For the trait of 1000-seed weight, Mahtab cultivar with 34.15 g at the control level and 37.33 g at the level of urea foliar application, had the highest grain yield among cultivars under drought stress conditions. For the trait of flag-leaf area, Makuei cultivar with 13.95 cm2 at the control level and Jolgeh cultivar with 14.27 cm2 at the level of urea foliar application, had the highest flag-leaf area among cultivars under drought stress conditions. For the trait of flag-leaf chlorophyll, Makuei cultivar with 44.4 units at the control level and Jolgeh cultivar with 46.48 units at the level of urea foliar application had the highest flag-leaf chlorophyll among cultivars under drought stress conditions. For the trait of flag-leaf proline content, Mahtab cultivar with 5.4 units at the control level and 3.12 units at the level of urea foliar application had the highest flag-leaf proline content among cultivars under drought stress conditions. In general, Mahtab cultivar, compared to other cultivars, had a smaller decrease in the amount of studied traits under drought stress conditions that indicates its greater resistance and adaptation to water shortage stress.

In general, the results showed that the cessation of irrigation at the stage of spike emergence in the used cultivars caused a significant reduction in the studied traits in both years of the experiment. However, urea foliar application was able to mitigate the adverse effects of water stress. So that the application of this element had a positive role in the studied traits barley cultivars especially in water shortage stress conditions. Study traits in used cultivars decreased in water shortage stress conditions that indicates the sensitivity of the studied cultivars to water shortage. Mahtab cultivar compared to other cultivars, was less reduction in the amount of studied traits under drought stress conditions. And also compared to other cultivars, was a further increase in flag-leaf proline content under drought stress conditions that indicates its greater resistance and adaptation to water shortage stress.

In order to investigate ascorbic acid effect on grain yield and some physiological traits of quinoa plant under water deficit stress conditions, an experimental in the form of split plots based on the randomized complete block design with three replications in two years at Research and Agriculture and Natural Resources Center Kerman was performed. The main factor included three levels of irrigation treatments (irrigation to the full maturity stage (control), irrigation to the beginning of the flowering stage, and irrigation to the beginning of the dough development stage) and the secondary factor included two levels of ascorbic acid foliar spraying (0 and 2 mM). The effect of irrigation factor and ascorbic acid and their interaction on seed yield and most of the measured physiological traits were significant. Water stress decreased grain yield, content of photosynthetic pigments, leaf protein content and relative water content and increased carbohydrate and proline content. The seed yield decreased by 40.5% and 18.7% under the conditions of irrigation to the beginning of the flowering stage and irrigation to the beginning of the dough development stage, respectively, compared to the control conditions. Foliar spraying with ascorbic acid led to the improvement of physiological traits and grain yield in all three irrigation treatments. Seed yield increased by 22.7% with ascorbic acid solution. Since foliar spraying with ascorbic acid improved seed yield in three irrigation treatments, it is suggested to use this substance to compensate for the damage caused to quinoa plant as a result of drought stress.

The pulses, including pinto bean have a great contribution to human nutrition by having a significant   protein content. Moreover, drought is one of the most important environmental stresses that negatively affects plant growth and development stages and consequently grain yield. In general, the most important effects of drought stress are the disruption of the photosynthetic apparatus, the reduction of stomatal conductance, premature leaf senescence and ultimately, the reduction of yield and yield components. However, the response of different plant genotypes to drought stress is different. About 60 percent of bean production in developing countries is done under drought stress. Iran is a country with a warm and dry climate that more than 85 percent of it located in arid and semi-arid regions. Therefore, the cultivation of pinto beans in Iran is carried out under drought stress conditions and we need to find a way to increase yield under drought stress conditions. One of the strategies to against drought stress is the introduction of tolerant and compatible plants. Accordingly, it is important to evaluate and select drought tolerant genotypes based on the traits that directly affect crop yield potential. Therefore, this study was conducted to evaluate 18 pinto bean genotypes under different irrigation regims.

This experiment was conducted in 2019 at Bean Research and Training Campus Farm, Khomein, using a 3-replicate split plot RCBD. The irrigation regimes as main plot consisted 50 (I1), 70 (I2) and 110 (I3) of cumulative evaporation using a standard class "A" evaporation pan.18 pinto bean genotypes (KS21336, KS-21359, KS-21331, KS21293, KS-920054, KS-21284, KS-21374, KS-21195, KS-21318, KS-21168, KS-21373, KS-21158, KS-21359, KS -21486, KS-21488, KS-21573, Ghaffar and Sadri) were considered as subplot. The grains of each genotype were planted in six rows with a length of three meters. Irrigation treatments were applied about 30 days after planting. Pest, disease and weed control were performed according to conventional methods during the growing period. Plants were harvested from each experimental unit at physiological maturity stage and leaf area index, leaf relative water content, plant height, grains per plant and in pod, pods number per plant, 100 grains weight, biological yield, grain yield and harvest index traits were recorded. In addition, the drought tolerance index was calculated to identify the tolerant genotypes of pinto beans. Analysis of variance (ANOVA) was performed using the GLM procedure in SAS (version 9.1; Cary, North Carolina, USA). The least significant difference test (LSD) was used to assess the significance of differences in treatment means at the 5 percent probability level.

Irrigation regimes caused a significant reduction in leaf area index, leaf relative water content, pods number per plant, grains number per pod, grains per plant, 100 grain weight, grain yield, biological yield and harvest index at I2 (27, 7, 25, 17, 37, 4, 6, 30 and 11 percent, respectively) and at I3 (41, 10, 45, 34, 60, 14, 23, 30 and 40 percent, respectively). In general, the rate of decreases was greater with increasing water stress intensity. Therefore, it can be concluded that drought stress negatively impacts plant growth and yield, with the severity of the stress playing a significant role. Drought stress can result in reduced photosynthesis, metabolic disturbances, and even plant mortality. Among the genotypes studied, KS-21318 exhibited the highest grain yield, followed by Ghaffar and KS-21158, respectively. Under normal irrigation conditions, grain yield demonstrated a positive and significant correlation with the number of grains per pod. In the I3 irrigation regime, characterized by severe stress, grain yield showed positive and significant correlations with the number of pods per plant, number of grains per pod, and number of seeds per pod. The pinto bean genotypes examined exhibited notable variations in leaf area index, plant height, number of grains per pod, number of pods per plant, grain yield, harvest index (HI), and drought tolerance index under both mild and severe stress conditions. The highest and lowest harvest index in I3 irrigation regime (severe stress) belonged to KS-21318 and Ghaffar genotypes. Among the studied genotypes, the highest and lowest mild drought tolerance index belonged to Ghaffar (1.17) and KS-21486 (0.387) genotype, respectively. As well as, the highest and lowest severe drought stress tolerances belonged to Ghaffar (1.12) and KS-21486 (0.373) genotype, respectively.

Correlation coefficients between traits showed that in order to breed pinto beans in terms of seed yield, the number of pods per plant, the number of seeds per pod and thenumber of seeds per plant should be considered. Among the studied genotypes, according to drought tolerance index in terms of grain yield, Ghaffar genotype was identified as drought tolerant genotype. In general, there was a significant variation among the studied genotypes in response to different levels of irrigation and this can be used to breed and select pinto bean for drought tolerance.

To evaluate the quantitative and qualitative forage yield of clover cultivars under water deficit, a split plots experiment was conducted in randomized complete block design with three replications at the Seed and Plant Improvement Institute, Karaj, Iran, for two cropping years (2017-18 and 2018-19). Three irrigation regimes included full irrigation (supplying 100% of clover water requirement), moderate stress (supplying 75% of clover water supply) and severe stress (supplying 50% of clover water supply) as the main factor, and five clover cultivars (Karaj, Elite, Ekinaton, Win and Alex) were evaluated as the sub-factor. The results showed that the maximum yield of fresh forage and dry matter in all three irrigation levels were obtained from Win and Karaj cultivars and the minimum from Ekinaton cultivar. The highest water use efficiency for the production of lactation energy at the irrigation levels of 100%, 75%, and 50% was obtained from Win, Alex and Elite cultivars, respectively. In water deficit stress, dry matter yield, metabolizable protein yield, content and yield of net lactation energy decreased, whereas metabolizable protein content increased. In addition, water deficit stress increased water use efficiency for the production of dry matter, metabolizable protein, and net lactation energy. Overall, due to the both quantitative and qualitative traits, Elite and Karaj cultivars are recommended as the best genotypes for cultivation under water deficit stress conditions.

Outcome appropriate strategy is so essential to reduce the irrigation of the turfgrass in the landspace since to high water requirement of turfgrass growth stages and the limitation of water resources. In the first experiment, the application of polyethylene glycol (0, 2.5 and 5%) and humic acid (0, 250 and 500 mg.l-1) treatments at the germination phase and the application of foliar spraying of humic acid (0, 250 and 500 mg.l-1) and drought stress (100% and 30% of field capacity) in the turfgrass establishment stage in the second experiment was conducted. In the first experiment, although the dry weight of seedlings increased at the presence of different concentrations of polyethylene glycol, most of the indices of germination decreased in comparison to the control. In the second experiment, drought stress in turfgrass caused 10-fold increase in proline, decreasing in relative water content, fresh and dry weight of shoots compared to withouth drought stress in greenhouse conditions. Foliar spraying with 250 mg.l-1 humic acid reduced shoot height and density under drought stress conditions. Therefore, it can be stated that the foliar spraying application of humic acid under field capacity irrigation can improve the physiological conditions, lead to increasing turfgrass density and shoot length nevertheless the use of acid humic foliar spraying was not effective in reduction the drought stress of turfgrass.