جستجوی مقالات مرتبط با کلیدواژه « تنش کمبود آب » در نشریات گروه « کشاورزی »

AbstractTo assess the effectiveness of plant growth-promoting bacteria (PGPB) on the agromorphological characteristics of Lemon balm under drought stress in the second year of cultivation, an experiment was performed in the form of split plots in randomized complete block design with three replications. The first factor includes three levels of drought stress (full irrigation, 75% and 50% of full irrigation) and the sub-factor was inoculation with PGPB in 5 levels including control (no bacterial inoculation) and inoculation with four bacterial species (Azospirillum, Bacillus strain A, Bacillus amyloliquefaciens and Streptomyces rimosus). Based on the obtained results, the effect of different levels of drought stress on all investigated traits was significant. Bacterial treatment showed a significant effect on the number of sub-branches, leaf area index, stem dry weight, percentage and yield of essential oil and biological yield in the first cut and leaf dry weight in the second cut. The interaction effect of stress and bacteria was significant only on the number of branches in the second cut. With the increase in the intensity of drought stress, a decreasing trend was seen in all the analyzed traits including in plant height, number of sub-branches, leaf surface, stem and leaf dry weight, percentage and yield of essential oil and biological yield while inoculation of the plant with Azospirillum, Streptomyces rimosus and Bacillus amyloliquefaciens bacteria caused a 10-20% increase in the studied traits compared to the control. Overall, bacterial treatments reduced the adverse effects of drought stress on the studied traits. According to this research, in order to improve the quantitative and qualitative yield and some agromorphological characteristics of Lemon balm under drought stress, inoculation of the plant with Azospirillum, Streptomyces rimosus and Bacillus amyloliquefaciens bacteria is recommended.IntroductionLemon balm (Melissa officinalis L.) is one of the herbaceous perennial medicinal plants that has a variety of uses. Nowadays, due to the increasing popularity of medicinal plants, the area under these plants’ cultivation continue to increase. However, problems such as drought stress limit the development of these plants’ cultivation. Plants respond to water deficit stress at morphological, biochemical and physiological levels and use different adaptation mechanisms to withstand drought stress. Plant growth promoting rhizobacteria (PGPRs) are soil bacteria that can increase crop plant growth and protect them against biotic and abiotic stresses through different mechanisms. In this regard, this study was designed and conducted to investigate the effectiveness of plant growth-promoting bacteria (PGPB) on the agromorphological characteristics of Lemon balm under drought stress in the second year of Lemon Balm cultivation under water deficit stress.Materials and MethodsThis experiment was performed during 2019-2020 growing season at the research field of the faculty of agricultural, Shahrekord University in the form of split plots in randomized complete block design with three replications. The first factor includes three levels of drought stress (full irrigation, 75% and 50% of full irrigation) and the sub-factor was inoculation with PGPB in 5 levels including control (no bacterial inoculation) and inoculation with four bacterial species (Azospirillum, Bacillus strain A, Bacillus amyloliquefaciens and Streptomyces rimosus). The amount of irrigation water was calculated using plant water requirement. In order to apply water stress, a moisture meter (Delta-T, SM-150T) was used to measure soil moisture content and the plants were irrigated when the respective MAD threshold was reached. Leaf area was measured with Digimizer software. After harvesting, first the plant height was measured and then the number of main and sub-branches was counted and the leaf dry weight, stem dry weight and biological yield were determined. The essential oils were extracted by hydro-distillation method using a Clevenger equipment. SAS software implemented for statistical analysis and the means were compared using LSD test.Results and discussionThe results showed that the effect of different levels of drought stress on plant height, number of sub-branches, leaf area, stem dry weight, leaf dry weight, essential oil percentage, biological and essential oil yield was significant. Bacterial treatment showed a significant effect on the number of sub-branches, leaf area index, stem dry weight, percentage and yield of essential oil and biological yield in the first cut and leaf dry weight in the second cut. The interaction effect of stress and bacteria only on the number of branches in the second cut was significant. With the increase in the intensity of drought stress, a decreasing trend was seen in all the analyzed traits including in plant height, number of sub-branches, leaf surface, stem and leaf dry weight, percentage and yield of essential oil and biological yield while inoculation of the plant with Azospirillum, Streptomyces rimosus and Bacillus amyloliquefaciens bacteria caused a 10-20% increase in the studied traits compared to the control. The highest essential oil yield, in both cuts was observed in inoculated treatment of Bacillus amyloliquefaciens.ConclusionThe results of this study showed that increasing drought stress causing significant reduction of all studied traits. However, bacterial treatments reduced the adverse effects of drought stress on the studied traits compared to non-inoculated at all drought stress levels. Among these bacterial treatments, Bacillus amyloliquefaciens had the most effect in improving the adverse effects of stress in all investigated traits and both cuts. According to this research, in order to improve the quantitative and qualitative yield and some agromorphological characteristics of Lemon balm under drought stress, inoculation of the plant with Azospirillum, Streptomyces rimosus and Bacillus amyloliquefaciens bacteria is recommended.

Multiple regression analysis and path analysis of maize grain yield with other agronomic traits to determine the most effective traits of the grain yield as well as analysis of genotype×trait interaction using the GGE biplot method, to evaluate the response of the hybrids to normal and water-deficit stress conditions based on the measured traits for determining high-yielding hybrids for both conditions, were carried out. In order to determine superior hybrids under normal and drought stress conditions based on agronomic traits and with the help of genotype×trait biplot analysis and also to determine traits affecting grain yield through multiple regression and path analysis, 18 maize hybrids were evaluated in a split-plot design based on the randomized complete block design in three replications and in two consecutive years.Two levels of irrigation were allocated in the main plots and maize hybrids in the subplots.In the path analysis of the grain yield with other studied traits, the number of kernel rows, the 300-grain weight and the number of grains per row under normal conditions, and the number of kernel rows and the 300-grain weight in the drought stress conditions had significant direct effects on the grain yield.The results of GGE biplot analysis of genotype×trait in both conditions showed that in normal conditions the two first components explained 72/28% and in water-deficit stress conditions 83/60% of the total variance.In both conditions hybrid SC704 was recognized as the ideal genotype.Hybrid SC704 ranked first as the most high-yielding hybrid in both conditions, and hybrid SC647 ranked next.

In order to evaluate the water deficit stress tolerance of 16 bitter vetch genotypes, two experiments were conducted in the cropping year 2014-2015 using randomized complete block designs with three replications in two conditions non- stress and water deficit stress at the research farm of Razi University, Kermanshah. Combined variance analysis of the data showed that the effect of environment on most traits was significant. Different stress tolerance indices including stress susceptibility index (SSI), tolerance (TOL), geometric mean production (GMP), mean production (MP), stress tolerance index (STI), yield index (YI), yield stability index (YSI) and harmonic mean (HAM) were calculated based on the yield data in the both conditions. MP, GMP and STI indices showed positive significant correlation with yield in the both conditions, and YI and HAM indices were correlated with yield in the stress conditions. Therefore, they were appropriate indices for selection of tolerant genotypes. Based on the biplot of the first two main components, genotypes 2, 3, 10 and 16 were identified as suitable entries for the both conditions.

Taking advantage of the symbiotic relationship between plants and Trichoderma fungi is one of the ways to reduce water stress in plants. The present study was conducted in order to investigate the effect of Trichoderma fungus on the antioxidant properties of the basil medicinal plant (Ocimum basilicum L.) under water stress conditions.

This experiment was carried out in the greenhouse of the Department of Horticulture Sciences of Ahar Faculty of Agriculture and Natural Resources and laboratory studies in the basic and general laboratories of Ahar Faculty of Agriculture and Natural Resources (University of Tabriz) in 2019 in a factorial manner based on a randomized complete block design with three repetitions. The treatments included different levels of water deficit stress, including severe stress (25% of field capacity), moderate stress (50% of field capacity), mild stress (75% of field capacity), and no stress (100% of field capacity). Each pot contained a commercial mushroom species Trichoderma harzianum Na-lac with concentrations of 109 and 106 spores per milliliter as the inoculum.

The results showed that the amount of malondialdehyde, catalase and peroxidase, antioxidant activity and total flavonoid increased with the application of dehydration stress. The concentration of 106 spores per milliliter had a better impact on improving the mentioned indicators. Based on this, Trichoderma fungus proves effective when improving the antioxidant status of plants under drought stress and can prevent the effects of oxidative stress in plants by reducing the oxygen free radicals produced.

The results indicated that the use of Trichoderma mushroom in comparison with the control (without inoculation with the mushroom) can be a suitable tool to improve the physiological traits and antioxidant activities in the conditions drought stress.

The quinoa plant (Chenopodium quinoa Wild) belongs to the Amarranthaceae family. This plant has a high nutritional value and shows tolerance to abiotic stresses such as drought and salinity. Drought stress is known as an important environmental stress that creates serious limitations for crop production all over the world. Drought stress may cause the production of reactive oxygen species in plants, which damages lipid and protein structures and causes the cell membrane to lose permeability and selectivity. Potassium is a mineral substance that is necessary for various biophysical and biochemical processes. It is important for the production of crops and can be a limiting factor for the production of crops under certain environmental conditions such as salinity and drought. Quinoa plant is somewhat resistant to drought and Kerman province is considered one of the dry areas. Therefore, cultivation of drought-resistant plants and strategies to increase drought resistance and improve agricultural and physiological traits in this plant are necessary. Considering that no research has been done in this field on quinoa plant in the climatic conditions of Kerman region, the present study was conducted to investigate the effect of potassium sulfate fertilizer on seed yield and some physiological traits of quinoa plant under different irrigation treatments.

The experiment of split plots based on randomized complete blocks design with three replications was conducted at the station of Research in the 2020-2021 crop year, Agriculture and Natural Resources Center in Kerman province of Iran. The main factor included three levels of irrigation treatment (irrigation to the full maturity stage (control), irrigation to the beginning of the flowering stage, and irrigation to the dough development stage) and the secondary factor included two levels of potassium sulfate fertilizer, including its application and non-application. Physiological traits including the content of chlorophyll a and b and carotenoids, ion leakage, malondialdehyde content and the activity of enzymes such as catalase, ascorbate peroxidase, peroxidase, polyphenol oxidase was measured. After confirming the normality of the data, the errors were also checked for normality. Then variance analysis of all traits and LSD mean comparison test at five percent level was performed with SAS software version 2.9.

The effect of irrigation factor and potassium sulfate on seed yield and all measured physiological traits (content of photosynthetic pigments, chlorophyll a, chlorophyll b and carotenoids), activity of antioxidant enzymes (catalase, peroxidase, ascorbate peroxidase and poly phenol oxidase), electrolyte leakage and malondialdehyde content) were significant. The highest seed yield (230.9 g/m2) was observed in control plants and the lowest (136.6 g/m2) in plants grown under irrigation conditions to the beginning of the flowering stage. Drought stress decreased the content of photosynthetic pigments and increased the activity of antioxidant enzymes, electrolyte leakage and malondialdehyde content. The application of potassium sulfate caused an increase in the seed yield compared to its non-application in all three irrigation treatments by an average amount of 25.8%. Physiological traits also improved with the application of potassium sulfate.

The yield of seeds and the amounts of photosynthetic pigments decreased in proportion to the increase in drought stress, and the ion leakage and malondialdehyde content increased, which indicated the harmful effects of this stress on growth parameters, photosynthetic apparatus, and cell membrane stability. The activity of antioxidant enzymes increased under stress conditions, which indicates the enzymatic defense responses to oxidative stress. The application of potassium sulfate led to the improvement of seed yield and physiological traits in both normal and drought stress environments alike. Due to the fact that drought stress affects the physiological traits and ultimately leads to a decrease in the seed yield of the quinoa plant, potassium sulfate fertilizer was used to compensate for its harmful effects.

In order to study evaluation of resistance to dryness  in two species of Bromos by using micorhyza symbiosis, a test has been conducted in split split plot in the form of block basis plan fully randomly by four iterations  in two agricultural  years  of 1396_1397 and 1397-1398 in the south of Tehran  province. The main  court consisted of dryness tension in three levels: 1-control(without tension in field capacity limit)(s1), 2-average tension (60%  field capacity )( s2), 3-intensive tension (40% field capacity )(s3)and minor  court also consisted of using  micorhyza fungus in three levels including:1-without micorhyza as 1- control (M1), 2-the specie of Glomus intraradices (M2) 3- specie of  Glomus mosseae (M3), two species  of Bromus plant considered as minor court  in two levels including:1_ (B1)Bromus kopetdaghensis (B1) -and Bromus tometolus (B2).Results showed that dryness tension  resulted in decrease of  number of leaf . Productivity geometrical average  rate (MP) and productivity arithmetical average (MP)in the average tension  condition was higher than intensive tension. Using Micorhyza species (M2) resulted in significant increase of  the number of  leaf, grass qualityand productivity  arithmetical  average  index. In the  comparison of average (S×M), tension  and application of micorhyza resulted in increasing  root length and dry weight of entire plant.The most  dry weight of entire plant in (S3M2)resulted to the rate of 6/8 grams and  root length  in (S3M3)gained 7/37 cm.Application of (M2) in the third level resulted in  1/21 %of dry weight of entire plant toward lack of application of micorhyza in this tension rate.Also tension resulted in  decrease of grass quality and in every three levels of dry tension ,application of micorhyza  resulted in significant increase of grass quality toward control and this increase in (M2)was more than (M3).In this test the greatest root length gained in (S3B2).In the comparison between interaction average (M×B),the greatest  root length  gained in (M3B2)condition.Based on the result of  interaction average  comparison,(S×M×B),the highest height of plant gained in the treatment (S1M2B2).The greatest  GMP in both years in tometolus grass species gained  along with the application of G.intraradices micorhyza species (M2B2Y1) and (M2B2Y2). Based on results of interaction  (S×M×B×Y),the highest stand to dryness index gained (S3M2B2Y2) and (S3M2B2Y1).In general, the species  Bromus tometolus and using of fungus species  Glomus intraradices suggested for this region in dryness tension condition.

Drought stress is one of the most important factors that limiting the growth and yield of plants. In recent years the use of various methods to reduce its negative effects has been considered by many researchers. This experiment was performed as a split plot in the form of randomized complete blocks with four replications in two years. The effect of foliar application of different ratios of magnesium and potassium on the morphological, biochemical and functional characteristics of maize (single cross cultivar 704) in different irrigation cycles (50, 75 and 100 mm evaporation from Class A evaporation pan) was evaluated. The results of analysis of variance showed that the interaction of irrigation and magnesium to potassium ratio on the characteristics of height, stem diameter, ear length, number of seeds per ear, potassium uptake, magnesium uptake, chlorophyll a, chlorophyll b, total chlorophyll, Carotenoids, proline, biological yield, grain yield and harvest index had a statistically significant effect. The results of the study of the effect of potassium and magnesium on morphological and biochemical changes in drought tolerance in maize (Single Cross 704 cultivar) showed that consumption of these elements significantly increased plant height, stem diameter, ear length, number of seeds per ear, uptake rate Potassium, magnesium uptake, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, proline, biological yield, grain yield and harvest index in water deficit conditions; So that the highest value of these traits in evapotranspiration conditions was 50 mm from the evapotranspiration pan and application of 200 kg of magnesium sulfate/ 300 kg of potassium sulfate. Also, foliar application of different concentrations of potassium sulfate and magnesium sulfate by increasing the uptake of potassium and magnesium, preserving leaf chlorophyll, resulting in more effective photosynthesis as well as increasing the concentration of proline in plant leaves, moderate the negative effects of water deficiency and corn tolerance to conditions. Improve water shortage.

In order to investigate the effect of water deficit stress and sources of nitrogen fertilizer on germination quality and vigor of wheat seeds of Chamran cultivar, an experiment was conducted in Agricultural Research Center of Fars province. In this experiment, wheat seeds were first treated at three levels of water deficit stress (complete irrigation, water deficit stress in milky and rough stage) and four levels of nitrogen fertilizer sources (urea fertilizer 100% plant requirement, urea fertilizer 25% Along with nitroxin and nitrogen, 50% urea fertilizer with nitroxin and nitrogen, 75% urea fertilizer with nitroxin and nitrogen were produced. Then, the quality and vigor of the seeds were tested in two standard experiments of germination and accelerated aging in a factorial design with four replications. The results showed that the effect of experimental treatments on all measured traits except germination percentage was significant. Water deficit stress and sources of nitroxin and nitrogen fertilizer with 25% urea at the beginning of decline led to an increase in protein concentration (12.39%), but the lowest amount of starch (20.85 %) under the interaction of nitroxin and nitrogen fertilizer with 75% urea in 48 hours Deterioration was observed. Water deficit stress also increased the concentration of soluble sugars and decreased the grain alpha-amylase enzymes. Overall, the results of this study showed that the use of combined treatments of urea fertilizer and biofertilizers in stress conditions to feed the mother plant led to the production of seeds with higher vigor and more resistance to decay.

Mungbean (Vigna Radiata L. Wilczek) is considered as one of the important tropical and semi-tropical pulses. This plant is important in terms of nutritional value, hay supply, green fertilizer and improvement of soil fertility (Al-Shaheen et al., 2016). According to the previous studies, water deficit causes morphological, physiological and biochemical changes within the plants, thereby negatively affecting their growth and yield. Various studies also suggest that water stress restricts nutrients absorbed by the plant as the absorption of nutritional elements and the water available for the plant roots are closely dependent on each other (Aghdasi et al., 2018). Therefore, spraying liquid fertilizer can be offered as an appropriate method of feeding the plant in this condition (Alipour & Zahedi, 2017). In this regard, the choice of the landraces and suitable cultivars and nutrition and irrigation management can play an important role in increasing quantity and quality of pulses and reduce negative effects of various environmental stresses. The present research aimed to study the effect of water deficit stress on some quantitative and qualitative traits of mungbean Parto variety under the foliar application and non-application of nano iron and manganese chelates.

In other to determine the effect of water deficit stress and nano Fe and Mn chelates foliar application on yield of mungbean cultivar Parto in 2013-14, an experiment was carried out in the agricultural research farm station of Tarbiat Modares university, Tehran as a split plot in a completely randomized block design with three replications. The experimental treatments in the main plots were three levels of irrigation regime [no cessation of irrigation (S1), cessation of irrigation at reproductive stage whenever 70 % of the field capacity (FC) was depleted (S2), cessation of irrigation at vegetative stage whenever 70 % of FC was depleted (S3)]; and in the subplots were 10 levels of foliar application [no foliar application of the nano fertilizers as control (F1), foliar application of pure water (F2) including 1/1000 chelated nano iron (F3), 3/1000 chelated nano iron (F4), 1.5/1000 chelated nano manganese (F5), 3/1000 chelated nano manganese (F6), 1/1000 nano chelated iron+ 1.5/1000 nano chelated manganese (F7), 1/1000 nano chelated iron + 3/1000 nano chelated manganese (F8), 1.5/1000 nano chelated manganese + 3/1000 nano chelated iron (F9), 3/1000 nano chelated iron+ 3/1000 nano chelated manganese (F10] at withholding irrigation periods.

The results showed that the water deficit stress and the foliar application of iron and manganese nano-chelates significantly affected the most of the plant traits at 1% probability level. Among water deficit stress levels, the termination of irrigation at the reproductive stage resulted in the lowest yield and yield components, whereas the highest values for yield performance yields were obtained from control (optimum irrigation). The results showed that the highest values for the plant yield and yield components were achieved with different levels of foliar spraying of iron and manganese nano-chelates at the vegetative and reproductive stage, especially at the vegetative growth stage, while control (no spray) decreased the yield and yield components in the plant. Also, the interaction between the two main treatments were significant for the most of the traits at 1% probability level. The results showed that the quantum yield of PSII, due to increased the F0 and decrease in Fm and Fv, in mungbean grown under water-deficit conditions in reproductive (60.2) and vegetative (97.4) stages declined significantly in comparison to the control group.

The means comparison for the interactive effects of foliar spraying and water deficit stress suggested that the greatest grain yield was related to the treatment of optimum irrigation and simultaneous spraying pf one per a thousand nano chelated iron and three per a thousand nano chelated manganese (1765/3 Kg/ha) and the lowest yield was associated with the treatment of the water stress at the reproductive stage and no spraying (376/0 Kg/ha). The was found to be a high correlation between biological yield and other morphological traits, especially dry weight of the leaf (r=0/90**). Thus, it is suggested that these elements can be utilized as a factor for decreasing stress and also increasing productivity in the plants.

Estimation of the physiological responses in bread wheat helps to identify the effective mechanisms to improve yield production in adverse environmental conditions such as water-deficit stress. In this study, the inheritance of physiological traits and grain yield in two populations, namely “Parsi” × “Winter B. C. of Roshan” and “Sistan” × “Winter B. C. of Roshan” were investigated under two normal conditions and terminal water-deficit stress using the Generation Mean Analysis (GMA). The results of this experiment showed that grain yield decreased in both of crosses due to water-deficit stress, so that the average of grain yield decreased in “Parsi” × “Winter B. C. of Roshan”, from 12.66 g/plant to 10.03 g/plant, and in the second cross decreased from 12.93 g/plant to 9.68 g / plant. In normal condition of both crosses, the highest amount of narrow-sense heritabilityሺ݄௡ ଶሻ belonged to chlorophyll b content (52% -53%), leaf area index (50-58%) and total chlorophyll content (45-63%), respectively. In waterdeficit stress condition for the first population, the highest amount of narrow-sense heritability ሺ݄௡ ଶሻ belonged to the content of chlorophyll b (61%), leaf area (54%) and total chlorophyll content (68%), and in the second cross it belonged to content of chlorophyll a (78%) and leaf area (56%). The high amount of narrow-sense heritability for these traits illustrates that additive effects play a big role to control them. So, selection method could be effective method to improve the mentioned traits.

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In order to investigate the effect of different levels of water and defoliation on some quantitative and qualitative characteristics of medicinal plant Teucriumpolium (Calpoureh). An experiment was Factorial shame in completely design conducted at the center for Agricultural Research in Iranshahr city came in to force in autumn 2014. Treatment were combination of water stress on four levels (A1= -0.3, A2= -5, A3= -10, A4= -15 bar) and defoliation stress on three levels (B1= 0 , B2 =25 , B3 =50 perecent defoliation). The levels of water shortage as main treatment and defoliation levels were considered as sub-plots. For imposing drought levels, First, by using pressure plats method , and soil moisture content were determined various potential water and then weighed average soil and added water loss. Traits in this project were: SPAD ridings, Stomatal resistance, Canopy temperature, Leaf to steam ratio, Specific leaf weight, Percentage of dry leaves and root / shoot ratio were measured. The results showed that water stress canopy temperature and percentage of dry leaf in Teucriumpolium significantly. Defoliation stress also reduced SPAD readings in Teucriumpolium. Significant negative correlation was between leaf / stem ratio and different levels of water stress in the plant. Also, root / shoot ratio showed appositive correlation with different levels of water stress. With the increase of water stress and defoliation stress, quality characteristics (oil) Teucriumpolium was decreased. In generality can be said, Teucriumpolium the plants are sensitive to two stresses.

In this study, the interactive effects of soil moisture and SS levels were investigated on alfalfa (Medicago sativa c.v Garehyounjeh) shoot and root fresh weights, water use efficiency (WUE), and concentrations of some elements in a loam soil under greenhouse conditions. A factorial experiment based on a randomized complete blocks design with three replications was conducted with two factors: soil moisture at three levels (0.81 FC–FC, 0.56–0.75 FC, and 0.35–0.50FC) and SS at four levels (0, 15, 30, and 60 g/kg soil). When 10% of the alfalfa plants flowered, the shoot and root fresh weights, concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) and WUE of alfalfa plant were measured. The results showed that the main and interactive effects of SS and soil moisture on alfalfa shoot and root fresh weights, WUE, and concentrations of elements were significant (p≤0.01). The decrease in soil moisture content, decreased alfalfa shoot and root fresh weights, WUE, concentrations of Fe in the shoot and concentrations of P, Fe, and Na in the root (p≤0.05); while it increased concentrations of Cu in the root, and Cu and Zn in the shoot (p≤0.05). Effect of soil water content on concentrations of N, K, Ca, Mg, Zn, and Mn of the root depended on the level of SS. Concentrations of Mg, Fe, Zn, Cu, and Mn in the root and shoot and concentrations of P, K, and Ca in the root were increased (p≤0.05) with the use of SS and increase in its level. By increasing the SS level, shoot and root fresh weights were initially increased and then decreased (p≤0.05). Effect of SS on WUE depended on soil water content. With sufficient water supply (0.81FC–FC), WUE was increased with increment of SS level, while under water-deficit stress (0.35FC–0.50FC), application of SS up to 30 g/kg increased WUE but at the level of 60 g/kg, increase in the soil salinity reduced WUE (p≤0.05). To increase WUE and improve the nutrition and growth of alfalfa at similar conditions, 30 grams of SS per kilogram of soil may be recommended under both well-watered and water-deficit conditions. Although the use of sewage sludge had some beneficial effects in this experiment, the potential risks of heavy metals in long-term application of this organic waste should be considered and avoided.

Dehydration is the most important limiting factor in agricultural production in arid and semi-arid regions, and water shortages (especially at the reproductive stages) due to lack of precipitation and unequal distribution are inappropriate for limiting the yield. In this research, cross between the Gasspard cultivar (dehydrated susceptible parent) and DN11 line (resistant parent) was performed. F1, F2, F3, BC1 and BC2 generations along with parents, were planted in a randomized complete blocks design with three replications in normal and water deficit conditions for two consecutive years. Physiological traits were measured for single plant samples. Weighted analysis of variance showed that water deficit stress caused significant decrease in flag leaf area and unsignificant decrease in stomatal conductance. Generation mean analysis for Chlorophyll index was accompanied by different results in terms of regression fitted models for each environment, but for stomatal conductance, the results of the generation mean analysis were the same in both environments. In addition to additive and dominant effects, epistatic interaction effects also played role in the inheritance of all studied traits. Most of these effects were double-effects. In flag leaf area, additive, additive × dominant and dominant × dominant effects were involved in inheritance. In water relative content, in addition to these effects, dominant effect was also involved in inheritance. Generations variance analysis showed that the gene action was additive for relative water content, dominant for flag leaf area and over dominant (in both conditions) for stomatal conductance. The gene action for Chlorophyll index under stress and normal conditions were over dominant and additive respectively.

Drought stress is the most important environmental stress that affects many morphological, physiological and, especially, yield traits of arable crops. In this research, a cross between the cultivar Gaspard (dehydrated susceptible parent) and DN11 line (drought resistant parent) was performed. F1, F2, F3, BC1 and BC2 generations along with parents, were planted and compared in a randomized complete block design with three replications in normal and water deficit conditions for two years. Then, using generation means analysis and generation variance analysis; genetic parameters were investigated in normal and water deficit conditions. Weighted analysis of variance showed that water deficit stress had a significant effect on the reduction of 100 grains weight, volumetric weight and seed yield per plant. The results of mean generation analysis for 100 grains weight and volumetric weight were the same and the same regression models were obtained for two environments. In addition to additive and dominant effects, epistatic effects also played a role in the inheritance of all studied traits. Additive and dominant effects along with additive×dominant and dominant×dominant interactions effects had played a role in the inheritance of single plant yield, moreover, in biological yield, dominant and dominant×dominant interaction effects had played a role, too. Generations variance analysis showed that the gene action for plant height, 100 grains weight (both conditions), spike length, spikelet number per spike and number of seeds per spike were additive. For the number of spikes and grain yield per plant were dominant and for the volumetric weight (both conditions), overdominance was observed. The results of two generations mean and variance analysis in traits such as biological yield were not the same, which can be attributed to the degree of genetic dispersion and bi-directional dominance. In harvest index and grain yield, due to high environmental variability, narrow sense and broad sense heritability was low.

In order to investigate the relationship between agronomic and morphological traits affecting wheat yield, two genotypes of wheat (Gasspard cultivar and DN11 line), along with generations of crosses (F1, F2, F3, BC1 and BC2), were examined in a randomized complete block design with three replications in normal and water deficit conditions in two consecutive years in the field of Research Institute of Nuclear Agriculture of Karaj. Stepwise regression analysis showed that straw yield was the first trait that entered the model and alone explained 46% and 65% of grain yield per plant in normal and water deficit conditions, respectively. Following this trait, under normal conditions, number of grain per spike, 100 grain weight, number of tiller per plant and number of spikes per plant had the high effect on grain yield per plant, explained about 78% of the total variation. In water deficit condition, the number of grain per spike, number of spikes per plant, 100 grain weight and days to maturity justified 92% of the grain yield per plant. The results of path analysis showed that in normal conditions, 100 grain weight, grain number per spike, tiller number per plant, straw yield and number of spike per plant and in water deficit condition, number of spike per plant, number of grain per spike, 100 grain weight and straw yield had the most direct effect on grain yield per plant.

Mineral mulches, such as pumice, increase water retention of soil, reduce evaporation and optimum water consumption. Use of pumice, thus, can be effective in improving the performance and growth of plant under water stress condition. This research was performed in completely randomized block design with three replications, four levels pumice, without its use (as control), and use of 30, 60 and 90 tons of pumice per hectare and three levels of irrigation (at 50% severe stress, at 70% moderate stress and at 100% without stress, evaporation from class A evaporation pan to evaluate the effect of treatment on some physiological traits of corn (modified hybrid of Maxima). Physiological traits of corn, was affected significantly by pumice and irrigation. The highest and lowest chlorophyll index, leaf relative water content, stomatal conductance and dry and fresh weight biomass, were obtained from pumice treatment of 90 tons per hectare and the control. The highest and lowest leaf temperature was also obtained from treatments of control and 90 tons per hectare. Chlorophyll index of 90 tons treatment per hectare in comparison with control and 30 tons per hectare of pumice amounted to 52 and 26% respectively. Stomatal conductance of irrigation at 50% evaporation from evaporation pan in comparison with treatments 70 and 100% decreased by 42 and 23% respectively. Thus it can conducted that the use of the 60 tons per hectare of pumice and irrigation at 70% evaporation from evaporation pan would be effective and will significantly affect plant vegetative characteristics and yield of corn.

In order to evaluate the genetic diversity of oily sunflower lines, screening drought tolerance indices and identification of drought tolerant lines, 100 oily sunflower lines were evaluated in a simple lattice design under both well-watered and water-limited stressed conditions in 2016. Based on the potential (Yp) and stress (Ys) yield, quantitative drought tolerance criteria such as: mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP), harmonic mean (HM), stress susceptibility index (SSI) and stress tolerance index (STI) were calculated. Generally, the line with code number of 8 with average yield of 81.25 gr/plant and line 66 with average yield of 5.43 gr/plant showed maximum and minimum seed yield, respectively. Correlation analysis between drought tolerance indices with well-watered and water-limited stress yields revealed that indices such as MP, GMP, HM and STI are the most suitable criteria for screening sunflower lines. In well-watered and water-limited stressed conditions, the highest value of MP, GMP, STI and HM were observed in line 8. Regarding these four criteria and high values of Yp and Ys, line 8 was chosen as the best line for using as a parental line in hybrid varieties production and development of segregating populations.

Management of manure and chemical fertilizers application in the soil in terms of environmental impacts and performance of plants is important, especially in arid and semi-arid regions of Iran. A split plot experiment was carried out in a randomized complete block design with three replications at the research farm of Shahrekord University in 2014. Main factor was consisted of three levels of irrigation regimes including 100% (I1 or control), 75% (I2) and 50% (I3) of water requirement while 6 levels of manure application including 1) no amended fertilizer (control), 2) 25% urea fertilizer + 75% cattle manure 3) 50% urea fertilizer + 50% cattle manure 4) 75% urea fertilizer + 25% cattle manure 5) 100% urea fertilizer and 6) 100% cattle manure, were considered as subplot factor. Results showed that irrigation regime of I3 caused decreasing an contration of chlorophyll a, b and total, essential oil yield of flowering branch, leaf and stem while in caused 83 and 13.5 percent increase in the amount of carotenoids and proline compared to control, respectively. Fertilizer treatments, 25% urea fertilizer + 75% cattle manure, 50% urea fertilizer + 50% cattle manure, 75% urea fertilizer + 25% cattle manure, 100% urea fertilizer and 100% cattle manure caused significant increase in carotenoids content compared to control whereas the maximum carotenoids content with the average of 1.35 mg g-1 was obtained from the 25% urea fertilizer + 75% cattle manure treatment. A significant positive correlation was observed between chlorophyll a, b, total, essential oil percentage, essential oil yield of leaf and essential oil yield of flowering branches. Therefore, in order to obtain the maximum essential Moldavian balm under Shahrekord climatic condition, application of 50% urea + 50% cattle manure and full irrigation is recommended.

Water deficit stress limits agriculture crop production. Plant growth-promoting rhizobacteria (PGPR) play an important role in control of water deficit stress. Today, for improving of plant tolerance to stress and the production of healthy crops, the application of biofertilizers, including growth-promoting bacteria, is interest. The present study investigates the effects of two different PGPRs (Pseudomonas fluorescens and Sinorhizobium meliloti) on some physiological and morphological characteristics in fenugreek under water deficit stress. For this purpose, a factorial design based on randomized complete block design with four water deficit levels (100%, 80%, 60% and 40% FC) and four PGPR condition as control, Sinorhizobium meliloti, Pseudomonas fluorescens and combination of S. meliloti. and P. fluorescens with three replications were carried out. Irrigation treatments were applied after flowering of plants until harvesting. The results showed that leaf area, shoot and root fresh and dry weight, phosphorus and potassium content, and water use efficiency (WUE) were significantly improved by PGPR inoculation and individual use of PGPR was more effective, whereas seed yield was decreased in PGPR treated plants.