Interruption Of Irrigation Research Articles

Drought-stress tolerance potential in plum and prune rootstocks and cultivars (Prunus spp.) based on physiological and photosynthetical parameters

Drought stress and water crisis is a great limiting factor for the production of horticultural crops. The present study was carried out during 2021 and 2022 at Horticultural Science Research Institute, Kamalshahr, Karaj, Iran to identify the effect of drought stress in physiological and photosynthetic characteristics of Prunus spp. rootstocks and varieties of 4-year old Prunus spp. The factorial experiment was conducted in a completely randomized block design (CRBD) having 3 factors and 3 replications. Factors included 8 rootstocks, viz. Myrobalan 29C, Penta, Tetra, St. Julien, Mariana 2624, GF 677, GN 15 and Seedling as the first factor; 4 cultivars, viz. Greengage, Simka, NO 16 and Zochelo as the second factor; and drought stress conditions in two levels namely with interruption of irrigation for 14 days and without interruption of irrigation as the third factor. Drought stress decreased relative water content of leaves, stomatal conductance, transpiration, CO2 content in substomatal chamber, and water use efficiency. Zuchelo and Greengage varieties and GN 15 rootstock had the highest and Simka variety and Mariana 2624 and Myrobalan 29C rootstocks had the lowest stomatal exchanges and photosynthesis, respectively. Among the rootstocks; GN 15, GF 677 and Mariana 2624 showed better physiological stability under stress, and the most tolerant variety against drought stress was NO 16. Totally, grafting combination of cv. NO 16 and rootstock GN 15 has been identified as the most tolerant to drought stress.

Manganese and zinc effect on yield, fatty acid ratio, and maternal seeds germination of canola cultivars upon late-season drought stress

To mitigate the effects of drought stress on fatty acid compositions and seed germination, various hypothesis have been studied by researchers. In this study, the field experiments were conducted in two cropping seasons (2020–2021) to investigate the effect of micronutrients on some characteristics of canola cultivars under late-season drought stress conditions. The experiments were arranged in a factorial split-plot design with three replications. The main factors included irrigation regimes (regular irrigation and irrigation interruption at the flowering stage) and foliar applications of Zn and Mn after rosette stage (F1: none application, F2: ZnSO4, F3: MnSO4, and F4: ZnSO4+MnSO4). The third factor included three cultivars, including Nima, R15 and KS7, as subfactor. Limited irrigation at flowering stage reduced length of seedling (25% and 17%), weight of seedling (30% and 14%), and seed yield (42% and 29) in first and second year, respectively. Irrigation withholding at flowering stage reduced seed yield by 37, 27, and 42% in R15, Nima and KS7 cultivars, respectively. Based on the current experimental data, irrigation withholding at flowering stage caused severe stress to the plants, especially those with long-term growth periods such as R15 and KS7. By contrast, the minimum yield loss was obtained from Nima cultivar, an early mature cultivar. Overall, it is recommended R15 cultivar for normal irrigation and Nima cultivar for a drought environment when considered the acceptable seed yield in new plants. In general, it is suggested that a suitable performance of canola seeds is achieved by foliar application of manganese and zinc.

Development and evaluation of smart irrigation system to enhance the water use efficiency

<p>For this purpose, a moisture sensor device was designed and constructed in February and March 2019 to determine the appropriate time to stop irrigation in furrow irrigation. Testing the device in the laboratory and its application in the Farm of the Campus of Agriculture and Natural Resources, University of Tehran (Mohammad Shahr), Iran, from April to July 2019. The purpose of this study was to evaluate the performance of a smart sensor of soil moisture to determine the optimum depth of installation and recording of soil moisture at 10, 30, and 50 cm depths and different length ratios in furrow irrigation. Initially, calibration of the device was carried out on field soil, and based on the obtained validation, the device was transferred to the field. To achieve the goals of optimum depth of installation and optimum length, 36-meter furrows with a distance of 0.75 m were created in the field. Sensitive lengths in furrows with 0.5 L, 0.75 L, and 0.85 L ratios were selected as the starting points. The results showed that in the calibration and validation phases, the R<sup>2</sup> values were 0.93 and 0.95, respectively, and in the calibration and validation stages, the value of nRMSE was 80 and 13.81%, indicating good model training in the calibration stage. Also, the average RE parameter in estimating soil moisture was 2.74%, indicating the high accuracy of the device in estimating soil moisture. The results also showed that if the device was installed at a depth of 30 cm from the soil surface of the furrow and at 75% from the beginning of the field, the depth and runoff losses would be minimal and irrigation adequacy would be best compared to other depths and lengths. It is expected that with optimal water consumption and timely interruption of irrigation, deep losses and runoff will be avoided, and with low water consumption, the productivity of crops will increase.</p>

The effect of growth regulators and irrigation on remobilization and grain filling of bread wheat in tropical climatic conditions

To study the remobilization rate affected by growth regulators in wheat a field experiment was carried out in the south of Iran over 2017-2019 with a split-split plot design and three iterations in completely randomized blocks. The main plots were two irrigation regimes (full irrigation and irrigation interruption at the grain-filling stage), two wheat cultivars (Chamran 2 and Durum Karkheh cv.s) were as sub plots, and four growth regulators (control (no growth regulator), salicylic acid, jasmonic acid, and cytokinin) placed in sub-sub plots. Results revealed the significant impact of the triple interaction on grain yield. The highest grain yield (4803 kg/Ha) was observed for Chamran 2 cv. treated with complete irrigation and salicylic acid. Although grain yield declined by 15.5% in the Karkheh cv. with irrigation interruption at the grain-filling stage and non-administration of growth regulators, treatment with salicylic acid managed to attenuate the adverse impact of drought stress in grain yield. The highest current photosynthesis and its contribution were observed in cultivars treated with complete irrigation. Moreover, irrigation regimen and growth regulators each had significant impacts on proline, catalase enzyme, and stomatal conductance. Overall, results suggested that using salicylic acid in Chamran 2 cv. would be advisable to increase growth and grain yield and reduce decline under stress.

Morpho-physiological responses and growth indices of triticale to drought and salt stresses

Salinity and drought are two major abiotic stresses challenging global crop production and food security. In this study, the effects of individual and combined effects of drought (at different phenological stages) and salt stresses on growth, morphology, and physiology of triticale were evaluated. For this purpose, a 3 x 4 factorial design in three blocks experiment was conducted. The stress treatments included three levels of salinity (0, 50, and 100 mM NaCl) and four levels of drought (regular irrigation as well as irrigation disruption at heading, flowering, and kernel extension stages). The stresses, individual as well as combined, caused a significant decrease in chlorophyll contents, total dry matter, leaf area index, relative water content, and grain yield of triticale. In this regard, the highest reduction was recorded under combined stresses of 100 mM NaCl and drought stress at flowering. However, an increase in soluble sugars, leaf free proline, carotenoid contents, and electrolyte leakage was noted under stress conditions compared to the control. In this regard, the highest increase in leaf free proline, soluble sugars, and carotenoid contents were noted under the combination of severe salinity and drought stress imposed at the flowering stage. Investigating the growth indices in severe salinity and water deficit stress in different phenological stages shows the predominance of ionic stress over osmotic stress under severe salinity. The highest grain yield was observed under non-saline well-watered conditions whereas the lowest grain yield was recorded under severe salinity and drought stress imposed at the flowering stage. In conclusion, the flowering stage was more sensitive than the heading and kernel extension stages in terms of water deficit. The impact of salinity and water deficit was more pronounced on soluble sugars and leaf free proline; so, these criteria can be used as physiological indicators for drought and salinity tolerance in triticale.

The Effect of Stopping Irrigation, Potassium and low Consumption Elements on Growth Indicators of Fodder Corn

In order to investigate the effect of irrigation, potassium and low-use elements on the growth indicators of fodder corn 704, a study in 2022 in the form of split-split plots in the form of a basic randomized complete block design in three replications at the city of urmia was implemented. Irrigation treatment as the main factor in two levels (full irrigation and interruption of irrigation), potassium consumption as a secondary factor in two levels (no consumption and consumption of 200 kg/ha of potassium) and low-consumption elements as a secondary factor in three levels. (non-use, soil use and foliar spraying were low-use elements). Plant height, fresh fodder yield, stem and leaf dry weight, biological yield, flag leaf area, ear length and diameter, proline and leaf relative water content were studied. According to the results, the main effects of irrigation interruption were significant in reducing plant height, flag leaf area, ear length, fresh fodder yield, stem and leaf dry weight, and increasing proline. Potassium consumption had a significant effect in increasing plant height, biological yield, ear length and diameter, proline, and also reducing stem dry weight. The three-way interaction effect of irrigation interruption, potassium consumption and soil consumption of low consumption elements significantly increased leaf dry weight by 20% and proline by 0.34%. But in the condition of stopping irrigation and using potassium, the non-use of low-use elements increased the relative water content of the cell by 8% compared to the foliar application of low-use elements. Therefore, in the conditions of drought stress, the use of potassium together with low-use elements has improved the mentioned traits, under such conditions, the use of these elements is recommended for the cultivation of fodder corn in the region.

Investigation of the Effect of Thermal Tension in Hot Seasons and Interruption of Irrigation at the End of the Growth Season by Silicon Nutrient Solution Sulfonated With S8 Elemental Sulfur on Fresh and Dry Fodder Yield and Protein Content of Alfalfa (Medicago sativa L.)

This research is an introduction to the combined nutrient of mineral salts by Silicon sulfonated with S8 through aerial organs of the Alfalfa plant. This type of combined nutrition by S8 is called “Matrix Nutrition”. This experiment was launched in October 2022 to study the effect of S8 on increasing the yield of fresh and dry fodder and the percentage of Alfalfa protein content using combined nutrition or Matrix Nutrition on the aerial organ of Alfalfa plant in the condition of interruption of irrigation at the end of the growing season in Moghan region, Ardabil province in Iran. The experiment was carried out in 2 plots, each one being one-hectare land. (In the first plot, S8 was applied for 5 litres per 1000 litres of water in the growth stages as foliar spraying after each crop harvest. No S8 was applied in the second plot.) The 5th and 6th harvests coincided with a dry season in this region and no irrigation was applied in this experiment for the 5th and 6th harvests. Both plots were only irrigated similarly for 1st to 4th harvest. The results obtained from a total of 5 harvests of the Hamedani Variant Alfalfa plant in the Control Plot and 6 harvests of the Hamedani Variant Alfalfa plant in the Experiment Plot indicated the highest yield in the 1st plot treated with S8 in terms of fresh and dry fodder, percentage of dry materials of fodder and protein content with a significant difference of 1% and 5% compared to Control Plot. The difference between the two plots was: fresh fodder 11,610 Kgs/Hectare, i.e., 91.27% higher yield, dry fodder 4,099 Kgs/Hectare, i.e., 140.95% higher yield, increase in dry material percentage for 5.99% and higher protein content of fodder for 1.59% which indicated a significant positive effect of application of S8 nutrient solution as foliar spraying on the increase of yield in fresh and dry fodder in the growing season and specifically at the time of thermal tension (specifically on 2nd and 4th harvest in control plot on June and August) and interruption of irrigation at the end of growth season (5th and 6th harvest of experiment plot).

Transgressive Biochemical Response to Water Stress in Interspecific Eggplant Hybrids

In a climate change scenario, crop tolerance to drought must be urgently improved, as it represents an increasingly critical stress reducing agricultural yields worldwide. Although most crops are relatively sensitive to water stress, many of their wild relatives are more tolerant and may be used to improve drought tolerance in our crops. In this study, the response to drought of eggplant (Solanum melongena), its close wild relatives S. insanum and S. incanum and their interspecific hybrids with S. melongena was assessed. The plants were subjected to two treatments for 18 days: control, with irrigation every four days, and drought, with complete interruption of irrigation. Morphological and biomass traits were measured, and physiological and biochemical responses were analysed using stress biomarkers such as proline, flavonoids, and total phenolic compounds. Oxidative stress was quantified by measuring malondialdehyde (MDA) content. As a result of the drought treatment, plant development and tissue water content were seriously affected. Generally, water deficit also caused significant increases in MDA, proline, flavonoids, and total phenolics compounds. Our results comparing parental accessions reveal a better response to drought in one of the S. insanum accessions. The hybrid between S. melongena and S. incanum displayed a better response than the other hybrids and even its parents. The results obtained here might be helpful for future eggplant breeding programmes aimed at improving drought tolerance.

Evaluating drought stress tolerance in different Camellia sinensis L. cultivars and effect of melatonin on strengthening antioxidant system

• In this study, the tolerance of different cultivars to drought stress have been determined. • We can suggest cultivar DG 39 and DN as tolerant cultivars to drought stress, and this cultivar can be used in breeding programs (hybridization). • Exogenously applied melatonin improve the ability of tea seedlings to tolerate drought stress. Drought stress really restring the growth and development of tea plant and affecting quality and yield. In tea growing areas of Iran, drought stress is a serious problem that affects the yield and quality of green leaves, therefore introducing cultivars that tolerate drought stress is one of the breeding purpose. To distinguish the variations in four tea cultivars response to drought stress and the role of melatonin in reducing the destructive effects of drought stress, an experiment was done at Tea Research Center of Iran, using the factorial based on completely randomized design with three replicates. The first experimental factor was the cultivar at 4 levels (DG39, DG7, DN and Kashef) and the second factor was irrigation interruption treatment at 5 levels, including control (full irrigation), irrigation interruption for 7 days with 100 µm melatonin foliar application, irrigation interruption for 7 days without melatonin foliar application, irrigation interruption for 14 days with melatonin foliar application and irrigation interruption for 14 days without melatonin foliar application. The study indicated that the physiological and biochemical traits were significantly different among the cultivars and treatments. Based on some traits such as malondialdehyde, the activities of antioxidant enzymes (CAT, POD), carotenoid and polyphenol content, DG 39 and based on traits such as proline, total sugar and chlorophyll content, DN are introduced as the cultivars that showed better tolerance to drought stress and these cultivars can be used in future breeding programs. Also melatonin treatment significantly enhanced the drought tolerance of tea seedlings, as demonstrated by decreased membrane damage, raised the concentration of proline, total protein, and total sugar and enhanced the activities of catalase and peroxidase during drought stress.

Assessment of Zinc, Boron, and Iron Foliar Application on Wheat Yield and Yield Components Under Drought Stress

ABSTRACT While eliminating their deficiency, leaf consumption of micronutrients enhances the quantitative and qualitative yield of the plant. To examine the impact of irrigation regimes and foliar application of zinc, boron, and iron on wheat yield and yield components, an experiment was conducted in the form of split plots in Varamin (Iran) over two crop years 2016–17 and 2017–18. The main factor of irrigation regimes included three levels (Tr: regular irrigation, Ts: irrigation interruption at the onset of stem growth and Tss: irrigation interruption at the onset of stem growth and seed filling) and the secondary factor included foliar application of micronutrients at eight levels (MC: control), MB: foliar application of boron (B), MZ: zinc (Zn), MI: iron (Fe), MZB: Zn + B, MBI: Fe + B, MZI: Zn + Fe and MZBI: Zn + B + Fe). Irrigation interruption at the onset of stem growth and seed filling (Tss) led to a significant reduction in seed yield and its components. With an average of 6788 kg ha−1, the highest seed yield belonged to normal irrigation treatment. With an average of 6549 kg ha−1, Fe + Zn + B treatment had the highest seed yield, indicating a 17% increase compared to the control treatment. Given the positive effect of iron, zinc, and boron micronutrients on wheat agronomic characteristics, these treatments under normal irrigation and drought stress conditions are suggested to be applied for the development of wheat cultivation in cold temperate areas with semi-arid climate.

Distribution of Al, Fe, Si, and DOC between size fractions mobilised from topsoil horizons with progressing degree of podzolisation

Aluminium, Fe, Si, and dissolved organic C (DOC) accumulate in the subsoil of Podzols after mobilisation in the topsoil. We conducted laboratory experiments with topsoil horizons with progressing degree of podzolisation by irrigation with artificial rainwater at varying intensity and permanence. We monitored the concentrations and distribution of mobilised Al, Fe, Si, and DOC between size fractions (< 1000 Dalton, 1 kDa– < 0.45 µm, and > 0.45 µm). Total eluate concentrations were increased at the onset of the experiments and after the first irrigation interruption, indicating non-equilibrium release. There was no statistical effect of the degree of podzolisation on element concentrations. Release of Al, Fe, and DOC was mostly dominant in the fraction 1 kDa– < 0.45 µm, indicating metals complexed by larger organic molecules and colloids. Silicon released was dominantly monomeric silicic acid < 1 kDa. Particularly with the least podzolised soils, Al and Si concentrations < 1 kDa might have been controlled by short-range ordered aluminosilicates, while their transport in colloidal form was unlikely. Our study pointed to both quantitative and qualitative seasonality of element release during podzolisation, to decoupling of Al and Si release regarding size, and to different minerals that control element release as a function of the degree of podzolisation.

Responses of Canola Morphological and Agronomic ‎Characteristics to Potassium Sulfate Fertilization under ‎Drought Stress

ABSTRACT In order to reduce the damage caused by late-season drought stress of canola, a factorial split plot experiment was performed on the basis of the randomized complete blocks design with three replications in Karaj, Iran. The treatments were Potassium sulfate in two levels, including application and non-application of potassium sulfate, irrigation at three levels including normal irrigation (control), restricted irrigation from the flowering and pod formation stage, as factorial were in main plots and winter canola cultivars including Opera, L72, KR1, GKH3705, GKH0224 were in subplots. The interaction effect of potassium sulfate × irrigation × cultivar on plant height, number of pods per the main stem, number of pods per branch, number of pods per plant, seed yield, and seed oil yield was significant at the 1% level. In conditions of applying potassium sulfate and irrigation interruption from the flowering stage, Opera cultivar had the highest seed yield with a mean of 3715 kg ha−1. In conditions of not applying potassium sulfate and under normal irrigation (control), the promising line of L72 with a mean of 6169 kg ha−1, and in the late season drought stress (irrigation interruption from the pod formation and flowering stages), the opera cultivar with the means of 4763 and 3468 kg ha−1 had the highest seed yield.

Evaluation of the oil quality properties of Rapeseed genotypes contributed to drought stress at the flowering stage in semi-arid conditions

Climate change and water scarcity are among the significant limited factors to constrain the production and development of oilseed crops, especially rapeseed (Brassica napus L.), in arid and semi-arid areas. The effects of drought stress and late-sowing on the grain yield and oil quality of rapeseed were studied by conducting a factorial split-plot experiment as a randomized complete block design with three replications for two years (2015-2017) in Karaj, Iran. Irrigation and sowing date treatments were considered in the main plots as factorial, and cultivars were placed in subplots. Two sowing dates were considered; the regular date (October 7th) and the late-sowing date (November 6th). Irrigation was also carried out at two levels of normal irrigation and irrigation interruption from the flowering stage onwards. Experimental cultivars included ES Hydromel, ES Alonso, ES Darko, ES Lauren, and Ahmadi. The highest grain yield (4505.6 kg ha-1) was obtained on the regular date, and the normal irrigation. ES Hydromel had the best quality of oil and grain meal due to the highest percentage of palmitic acid (4.44%) under late cultivation and drought stress and the lowest glucosinolates content (23.19 μmol g-1 DW) under late cultivation. Therefore, the ES Hydromel hybrid cultivar was more successful in optimal use of water resources in the face of water scarcity and late-planting in arid and semi-arid regions.

Metabolic adjustment and regulation of gene expression are essential for increased resistance to severe water deficit and resilience post-stress in soybean.

BackgroundSoybean is the main oilseed crop grown in the world; however, drought stress affects its growth and physiology, reducing its yield. The objective of this study was to characterize the physiological, metabolic, and genetic aspects that determine differential resistance to water deficit in soybean genotypes.MethodsThree soybean genotypes were used in this study, two lineages (L11644 and L13241), and one cultivar (EMBRAPA 48-C48). Plants were grown in pots containing 8 kg of a mixture of soil and sand (2:1) in a greenhouse under sunlight. Soil moisture in the pots was maintained at field capacity until the plants reached the stage of development V4 (third fully expanded leaf). At this time, plants were subjected to three water treatments: Well-Watered (WW) (plants kept under daily irrigation); Water Deficit (WD) (withholding irrigation until plants reached the leaf water potential at predawn of −1.5 ± 0.2 MPa); Rewatered (RW) (plants rehydrated for three days after reached the water deficit). The WW and WD water treatments were evaluated on the eighth day for genotypes L11644 and C48, and on the tenth day for L13241, after interruption of irrigation. For the three genotypes, the treatment RW was evaluated after three days of resumption of irrigation. Physiological, metabolic and gene expression analyses were performed.ResultsWater deficit inhibited growth and gas exchange in all genotypes. The accumulation of osmolytes and the concentrations of chlorophylls and abscisic acid (ABA) were higher in L13241 under stress. The metabolic adjustment of lineages in response to WD occurred in order to accumulate amino acids, carbohydrates, and polyamines in leaves. The expression of genes involved in drought resistance responses was more strongly induced in L13241. In general, rehydration provided recovery of plants to similar conditions of control treatment. Although the C48 and L11644 genotypes have shown some tolerance and resilience responses to severe water deficit, greater efficiency was observed in the L13241 genotype through adjustments in morphological, physiological, genetic and metabolic characteristics that are combined in the same plant. This study contributes to the advancement in the knowledge about the resistance to drought in cultivated plants and provides bases for the genetic improvement of the soybean culture.

Salicylic acid mitigating damage to the photosynthetic apparatus and quality of Eugenia myrcianthes seedlings under water deficit

Abstract This study aimed to evaluate the effect of exogenous application of salicylic acid on the photosynthetic metabolism and quality of Eugenia myrcianthes seedlings under water deficit and their recovery potential after rehydration. Two water regimes were evaluated, as follows: control - plants irrigated daily (I) and water deficit (S), with and without the application of 400 mg L–1 of salicylic acid (SA), totaling four treatments. Seedlings were evaluated at three times: at the beginning of the experiment (T0), that is, when the irrigation was interrupted; when the photosynthetic rate reached values close to zero (P0 - 15 days after irrigation interruption), that is, when irrigation restarted; and when the photosynthetic rate was recovered (REC). Eugenia myrcianthes seedlings were negatively affected when subjected to water restriction; salicylic acid attenuated the damage to the photosynthetic apparatus by acting positively on the relative water content in the leaves, SPAD index, photosynthetic metabolism, superoxide dismutase and peroxidase enzyme activity, and seedling growth in P0. Eugenia myrchiantes presented potential for recovery after resumption irrigation. The application of SA contributed to the maintenance of gas exchanges, photochemical processes and quality of E. myrcianthes seedlings during and after water deficit, suggesting the promotion of plant resistance induction.

Evaluation crop indices of canola spring genotypes in terminal drought stress conditions and foliar application of Potassium silicate

Introduction Drought is a restriction in crop production in arid and semiarid regions. It is forecast that climate change may cause droughts shortly. After oxygen, silicon (Si) is the second most common element in the soil. In reducing both biotic stress (e.g., plant diseases and pest damage) and abiotic stresses such as salinity, drought, aluminum toxicity, heavy metal toxicity, nutrient imbalance, lodging, radiation, high temperature, wounding, and freezing. Materials and Methods In order to study the effects of terminal drought stress and foliar application of potassium silicate on yield and canola spring genotypes components, a factorial split-plot test was conducted in Karaj, Iran in a full randomized block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG × AL, RGS × SLM, DALGAN, RGS003 and RGS × Okapi in subplots. SAS Ver 9.1 statistical analysis was used for variance analysis. Results Combined variance analysis showed that the impact of the year on some characteristics seed number in silique, silique length and seed yield was significant. Also, the effect of irrigation was significant on seed yield. The effect of genotype on plant height was significant indicating that the genotypes had different reactions. The interaction effect of irrigation × genotype on Harvest index was significant. The interaction effect of Irrigation × Potassium Silicate × Genotype on branch number, silique number, silique length, seed number in silique, seed weight, biological yield, seed yield, oil content and oil yield was significant. The mean comparison of irrigation and Potassium silicate interaction demonstrated that the most grain yield was observed in normal irrigation and the least value related to cut off irrigation at pod formation stage. The results indicated that, irrigation, foliar application of Potassium silicate and their interaction had significant effect on growth and agronomic traits and increased them. Conclusions Finally, our study showed the beneficial effects of Potassium Silicate in improving the drought tolerance of canola plants, especially at the end of the season. This can provide a basis for attempting new strategies to reduce the damage from drought and create a functional link between the role of silicon, physiological response and tolerance to drought stress in canola plants. According to the results, in the case of application of Potassium Silicate and normal irrigation, the promising genotype of OG×AL, with the highest seed and oil yield, is recommended as standard. Also, in the case of application of Potassium Silicate and late-season drought stress (restricted irrigation from the pod formation stages), RGS × SLM and DALGAN with the highest seed yield, is recommended.

Cycocel, iron and zinc effects on yield and physiological characteristics of wheat under drought stress conditions

A factorial split-plot experiment was performed in order to investigate the effect of foliar application of cycocel, iron and zinc micronutrients on the yield and some physiological traits of wheat under drought stress conditions in the form of complete randomized block design with three replications for two crop years in Robat Karim area (south of Tehran). In this study, irrigation at two levels (i1: normal irrigation and i2: irrigation interruption from the beginning of the reproductive stage) was considered as the main factor, the cycocel application at two levels (c1: non-application and c2: cycocel application at 0.5 L ha−1) and foliar application of micronutrients at four levels (f1: pure water (control), f2: iron foliar application, f3: zinc foliar application, and f4: iron + zinc foliar application (each at a ratio of 0.3%) were considered as the secondary factors. The application of cycocel under both normal irrigation and stress conditions at the reproductive stage increased seed yield and yield components. Iron + zinc foliar application with a mean of 5543 kg ha−1 had the highest seed yield while the lowest value belonged to the control treatment (pure water) with a mean of 4638 kg ha−1. In general, given the positive effect of cycocel and iron and zinc micronutrients on wheat crop characteristics, the application of these treatments under normal irrigation conditions and late season drought stress are recommended for the development of cultivation in temperate cold regions with semi-arid climate.

Irrigation and passive drainage of pancreatic stump after distal pancreatectomy in high-risk patients: an innovative approach to reduce pancreatic fistula

IntroductionPostoperative pancreatic fistula (POPF) represents the most common form of morbidity after distal pancreatectomy (DP). The aim of this study was to illustrate an innovative technique of irrigation and passive drainage to reduce clinically relevant POPF (CR-POPF) incidence in high-risk patients undergoing DP.Material and methodsTwelve consecutive high-risk patients received irrigation and passive drainage of the pancreatic stump with a Salem sump drainage after DP. The Salem sump was irrigated with 100 ml/h of Ringer solution for 2 postoperative days (POD). In the case of low-drain amylase and lipase levels on POD 3, the irrigation was reduced to 50 ml/h. Persistence of low-drain pancreatic enzymes on POD 4 allowed for interruption of irrigation and subsequent removal of drainage from POD 7 onward in the absence of evidence of any pancreatic fistula.ResultsOverall, 16.6% of the patients experienced a grade 3 or higher surgical complication. We experienced only one case of POPF: the fistula was classified as grade B and it was managed with radiologic drainage of the fluid collection. We did not experience any case of re-operation nor in-hospital mortality.ConclusionsIrrigation with passive drainage of the pancreatic stump after DP is an interesting approach for CR-POPF prevention in high-risk patients.

Grain yield and associated physiological traits of rapeseed (&lt;em&gt;Brassica napus L.&lt;/em&gt;) cultivars under different planting dates and drought stress at the flowering stage

The adverse effects of abiotic stresses have always restricted oilseed crop production, particularly in arid and semi-arid regions. On the other side, global climate change has led us to adapt planting dates and select tolerant cultivars to encounter the new climatic conditions. To evaluate the effect of late-season drought stress under different planting dates on rapeseed cultivars, an experiment was conducted as a factorial split-plot based on randomised complete block design in Karaj region-Iran, during 2015-2017. Planting date and irrigation treatments were considered in the main plots as factorial and cultivars were placed in subplots. Two planting dates were regular date (October 7) (PD1) and late planting date (November 6). Irrigation was also carried out at two levels of normal irrigation (NI) and irrigation interruption from flowering stage onwards. Experimental cultivars included ES Hydromel, ES Alonso, ES Darko, ES Lauren, and Ahmadi. According to the results, late-season drought stress and delayed planting date reduced leaf relative water content (LRWC), total chlorophyll content, proline, and grain yield, and increased stomatal resistance (SR), canopy temperature, and leaf soluble carbohydrates (CLS) in rapeseed cultivars. The highest grain yield (4505.6 kg ha–1) was obtained in NI conditions and PD1. Significant interactions of planting date, irrigation, and cultivar on LRWC, SR, and CLS traits indicated that the ES Hydromel was the most tolerant hybrid cultivar with the highest LRWC and the lowest SR and CLS levels compared to other ones in unfavourable conditions of late-season drought stress and delayed planting. To confirm these results, cluster analysis led to the formation of two clusters, where ES Darko, Ahmadi, and ES Lauren cultivars were placed in the sensitive cluster and ES Hydromel and ES Alonso cultivars were assigned to the tolerant cluster. Therefore, ES Hydromel can be introduced as a superior cultivar to be selected as a genotype that presents acceptable resistance under drought stress and late sowing in arid and semi-arid regions. Highlights- ES Hydromel as a new hybrid cultivar under late-season drought stress conditions is proposed in cold temperate regions with arid and semi-arid climates. - Late sowing date has extremely caused a negative effect on the winter rapeseed’s physiological traits during the cold season. - The result of cluster analysis based on grain yield loss led to the formation of two clusters, which ES Hydromel and ES Alonso with lower yield loss were grouped in the tolerant cluster. - ES Hydromel in the late planting date and irrigation interruption conditions obtained the lowest stomatal resistance. - ES Hydromel on regular date and normal irrigation conditions obtained the highest leaf relative water content.

Effects of foliar zinc application on yield and oil quality of rapeseed genotypes under drought stress

In order to address the effect of zinc sulfate on stability and improvement of quality of rapeseed genotypes at different severities of drought stress, an experiment was carried out for two crop years in Karaj (Iran). Zinc sulfate included two levels of non-application and application of 50 g L−1 zinc sulfate, and irrigation was applied in three levels including normal irrigation and irrigation interruption from the podding and flowering stages as factorial in main plots and five rapeseed genotypes in subplots with three replications. Under the conditions of zinc sulfate application and normal irrigation, the L155 genotype had a seed yield of 6310 kg ha−1, the highest oleic acid percentage (67.3%), and the least glucosinolate content (0.8 μmol g−1). Furthermore, under conditions of zinc sulfate application and irrigation interruption from the podding stage, HL2012 and L155 genotypes, respectively produced seed yield of 5032 and 4826 kg ha−1, the highest oleic acid percentage (65.8 and 65.7%), and the lowest seed glucosinolate (11.3 and 11.8 μmol g−1). Moreover, under the conditions of irrigation interruption from the flowering stage, HL2012 and L155 genotypes had the seed yield of 3679 and 3606 kg ha−1, the highest oleic acid percentage (64.3 and 64.2%, respectively) and the lowest glucosinolate (14.5 and 14.8 μmol g−1, respectively. In general, the positive effect of zinc sulfate application on traits such as seed oil yield increased with increasing drought stress, and the L155 genotype is recommended for all irrigation conditions, while the HL2012 genotype may be suggested for late-season drought stress for cultivation in cold temperate semi-arid areas.