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Achieving sustainable agricultural productivity is critical due to the rising worldwide demand for food and the growing scarcity of water. This comprehensive review investigates the complex interrelations where integrated irrigation and nitrogen management are used as a strategic method to improve wheat crop yields and water use efficiency (WUE). The study synthesizes current research findings, methodologies, and technological advancements related to optimizing water and nitrogen inputs in wheat cultivation. A number of factors can affect WUE in wheat, including climate, soil, crop management practices, and genetic factors. There are a number of irrigation and nitrogen management practices that can be used to improve WUE in wheat, including deficit irrigation, mulching, and split applications of nitrogen fertilizer. The review underscores the significance of tailored irrigation and nitrogen management strategies in mitigating water stress, reducing nutrient runoff, and promoting sustainable agricultural practices. Insights from this comprehensive analysis aim to guide policymakers, agronomists, and farmers in making informed decisions for optimizing wheat production while conserving water resources and minimizing environmental impact. Future research on WUE can help to ensure that wheat production remains sustainable in the face of future challenges such as climate change and water scarcity.
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A field experiment was conducted at the Regional Research Technology and Transfer Station (RRTTS), Chiplima, Sambalpur, Odisha during summer season of 2019 & 2020 to evaluate performance of medium duration rice varieties with varying irrigation schedules under aerobic condition. The experiment was laid out in split-plot design with 3 replications and consisted of four irrigation schedules i.e. I1 = Irrigation at IW/CPE = 1.0, I2 = Irrigation at IW/CPE = 1.5, I3 = Irrigation at IW/CPE = 2.0, and I4 = Irrigation at IW/CPE = 2.5 in main plot treatments and four varieties i.e. V1 = Naveen, V2 = MTU-1010, V3= CR Dhan-201 and V4 = CR Dhan-204 in subplot treatments.The result of pooled mean of both the years showed that higher grain yield was recorded at IW/CPE = 2.5 i.e. 4.07 t/ha , which was at par with IW/CPE = 2.0 (3.90 t/ha) and significantly superior to rest of other irrigation schedules. But in case of cultivars, higher grain yield was obtained with variety CR-Dhan 201(3.54 t/ha) which was at par with variety Naveen (3.30t/ha) and significantly superior to rest of other cultivars. The interaction of irrigation at IW/CPE 2.0 with variety CR Dhan 201 gave the highest grain yield (4.39t/ha) which was at par with irrigation at IW/CPE 2.5 with variety CR Dhan 201 (4.30 t/ha) and significantly superior to rest of other interactions. The interaction of irrigation schedules at IW/CPE 1.5 with Naveen variety produced the highest field water use efficiency (44.05 kg ha-cm-1) but it was at par with all irrigation schedules except at IW/CPE 2.5 with variety CR Dhan 201. Hence, it may be concluded that variety like CR Dhan 201 needs to be irrigated at IW/CPE 2.0 produced economically optimum yield and field water use efficiency on sandy loam soils of western region of Odisha under aerobic condition.
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Papaya (Carica papaya L.) is a significant fruit crop cultivated worldwide in tropical and subtropical regions. However, its cultivation is often constrained by limited water availability and soil moisture stress, which may significantly affect its yield and quality. This study aimed to explore the effects of irrigation levels and straw mulch on the growth and yield of papaya under a drip irrigation system. The experiment encompassed six treatments: three different irrigation levels (100%, 75%, and 50% of crop water requirement) and two mulch levels (straw mulching and no mulch). The effect of mulch levels on plant growth, yield, and water use efficiency was statistically significant. The results revealed that applying 100% of crop water requirement along with straw mulch resulted in the maximum plant height, stem girth, crown diameter, and yield compared to the no mulch treatment. The study also evaluated irrigation water use efficiency, an essential aspect of sustainable farming practices. The results indicated that the maximum irrigation water use efficiency (58.47 kg m-3) was recorded when 50% of the crop water requirement was met alongside straw mulch. Conversely, the minimum irrigation water use efficiency was observed when 100% of the crop water requirement was completed without any mulch under the drip irrigation system.
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One of the most essential inputs for agriculture is water. Moisture stress at critical growth stages in wheat severely effects the growth and yield. Hydrogel (water-absorbing polymer) can keep the appropriate moisture level at the root zone depth and protects the crop from adverse effect of moisture stress. The present trial was conducted during rabi season of 2020-21 to assess the performance of different hydrogels under different levels of irrigations on growth, yield, and water use efficiency of wheat. Results revealed that application of 3 irrigations recorded significantly maximum number of tillers per m2 at 90 Days After Sowing and at harvest. The application of Nano hydrogel @ 20 kg ha-1 significantly increased the number of tillers per m2 at 90 DAS and at harvest over control. Significantly maximum grain (26.1%) and straw (24.5%) yield were obtained with 3 irrigation levels over one irrigation. The Nano hydrogel increased grain (33.6%) and straw (22.9%) yield significantly over control. Water use efficiency significantly improved with one irrigation over 3 irrigation levels, application of Nano hydrogel @ 20 kg ha-1 significantly increased WUE.
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This study aimed to optimize irrigation scheduling for maize (Zea mays L.) using the crop water stress index (CWSI) to improve water use efficiency and yield. The study was conducted in the South farm of the School of Agricultural Sciences, Karunya Institute of Technology and Sciences, Coimbatore during the Kharif and Rabi seasons of 2022. A randomized block design was used with seven treatments, including a control T1 no irrigation). Irrigation at all critical stages (T2) and other five irrigation treatments (T3 to T7) based on different CWSI values ranging from 0.2 to 1.0. Infrared thermometry was used to measure canopy temperatures for estimating the CWSI. The results showed that irrigation at 0.2 CWSI (T3) had a significant positive effect on kernel and stover yield when compared with all the other treatments during both the seasons, with the highest kernel yield of 7138.83 Kg ha-1 and 8014.8 Kg ha-1, stover yield of 11134 Kg ha-1 and 12765 Kg ha-1, respectively and lowest kernel yield of 2267 Kg ha-1 and 2325 Kg ha-1, stover yield of 8156 Kg ha-1 and 6491 Kg ha-1, respectively. The other treatments had intermediate values and did not show any consistent pattern. Irrigation at 0.2 CWSI resulted in the highest water use efficiency (WUE) of 14.7 Kg ha-cm-1 and 17.6 Kg ha-cm-1, and irrigation usage of 31.73% and 22.26% during the Kharif and Rabi seasons of 2022, respectively and the lowest water use efficiency (WUE) of 7.72 Kg ha-cm-1 and 17.6 Kg ha-cm-1 was found in T7 during the Kharif and Rabi seasons of 2022, respectively. The results suggest that irrigation at 0.2 CWSI could be a promising option for achieving higher kernel and stover yields with minimal water use and maximum WUE and IUE.
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This study examines the intercropping system of wheat and mentha involves the simultaneous cultivation of two or more crops on the same piece of land for higher land productivity. Japanese mint, a member of the Lamiaceae family, has a potent essential oil. Oil extracted from the leaves for use in aromatherapy, food flavouring, and medicine. Hence, a field experiment was conducted to study the effect of Row ratio and Planting methods on Growth, Yield Performance of wheat (Triticum aestivum L.) and Mentha (Mentha arvensis L.) was conducted during 2016-17 at the Soil Conservation and Water Management Farm to investigate the response of mentha when intercropped with wheat under various row ratio and planting methods. The experiment was laid out in Randomized Block Design (RBD) with three replication keeping one variety of Mentha ‘Shivalik’& Wheat ‘Unnat Halna’. The experiment consisting of nine treatments are T1: Sole Mentha direct sowing (50cm apart), T2: Sole Mentha transplanting (50cm apart), T3: Sole Wheat (25cm apart), T4: Wheat+Mentha (d, 1:1), T5: Wheat+Mentha (t, 1:1), T6:Wheat+Mentha (d, 2:2), T7:Wheat+Mentha (t, 2:2), T8: Wheat Paired+Mentha (d, 2:3), T9: Wheat Paired+Mentha (t, 2:3). The results indicated that Sole Wheat (T3) had the highest plant population (662.40 initially, 326 final), plant height (83.80 cm), and grain yield (39.80 q/ha) for wheat. In the case of mentha, Wheat Paired+Mentha (T8) exhibited the maximum final plant population (119.43), plant height (72.51 at maturity), and equivalent oil yield (189.05 l/ha). Wheat Paired+Mentha (T8) also recorded the highest total water use (647 mm), water use efficiency (0.292 kg/ha/mm of water), land equivalent ratio (1.50), and economic parameters such as gross return (228,868), net return (160,828), and B:C ratio (3.36). The maximum oil yield (163.35 l/ha) was found in Sole Mentha direct sowing (T1).
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Genetic variability is a major component which helps in selecting better genotypes under different environmental conditions. Thus, this study was conducted to understand the genetic variability and its components and their trait associations of yield characters from the cross of GKVK-13 and KCG-2 that contribute to the F6 and F7 families. In an augmented block design with three checks, TMV-2, KCG-6, and KCG-2, the study was carried out at the University of Agricultural Sciences, Bangalore, in the 2017 summer and Kharif (rainy seasons). Highly significant differences between the families were found in the analysis of variance for all the characters studied in the F6 and F7 generations, indicating that there is enough variation. Furthermore, medium to high Phenotypic coefficient of variation and Genotypic coefficient of variation values coupled with high heritability and medium to high genetic advance as per cent mean observed in most of the traits showed that the majority of the attributes were controlled by additive gene activity and that there was adequate variability. In addition, phenotypic correlation coefficients depicted significant positive associations for most of the traits studied. The implications of the results are discussed. The study concludes that there was the presence of additive genes controlling most of the traits and early selection of these traits is possible for groundnut improvement in the breeding programme.
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Assessing the potential impacts of climate change on crop evapotranspiration (ET), groundwater contribution (GWC) towards meeting ET and yield is crucial in allocating water resources particularly in the areas where shallow water-table depths (WTDs) are expanding on larger area. The impact of climate change on crop ET and yield has been evaluated in the past by indirect methods using simulation models. However, those models are lacking the function of GWC which is one of the most important parameters while determining ET at different water-table depths (WTDs) and its impact on yield. Direct methods (without simulation models) using long term historical weather data (observed data) provide more accurate results of climate change impact on ET, GWC towards meeting ET and yield at different WTDs. In this study, long-term historical weather data for the last 34 years (1987-2020) and data obtained through lysimeteric studies were analyzed to examine the trends of climatic parameters, their relationship and impact on wheat and cotton ET, GWC to ET, yield and water use efficiency (WUE). These studies were carried out during 1986-1987 and 2017-2021 periods at 1.50 m, 2.25 m, and 2.75 m WTDs in Sultanpur soil series (silt loam textured) and Miani soil series (silty clay loam textured). The mean daily temperature has increased 0.45 oC and rainfall 75.5 mm/year over a period from 1987 to 2020 which is witnessing the climate change. Wheat ET is increased, GWC contribution to ET is decreased and, yield and WUE is highest during the cropping periods of 2017-2021 as compared to 1986-1987. Climate change has decreased cotton ET and GWC towards meeting ET. It has also reduced the wheat and cotton cropping cycles by 8 days and 21 days, respectively. Higher magnitude of rainfall (during July-September) in 2019 and 2020 resulted in reducing cotton average yield of 2017-2020 compared to 1987. The study demonstrates that irrigation allocation should be increased for wheat and decreased for cotton particularly in the shallow water-table areas under Sultanpur soil type where water-table remains at 1.50 m – 2.25 m depths. Moreover, cotton crop should be cultivated by the 1st week of April, so that highest yield of cotton could be harvested before onset of monsoon.
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Remote sensing has played a vital role in advancement of agriculture and is effective technical method for agriculture crop management. It is a technology which acquisite information regarding objects on earth surface as well as atmosphere from a distance without being in contact with the object. Researchers have proved its high potential with accuracy in the field of agriculture. After various experiments, the qualitative and quantitative assessment of soil, crop and atmosphere demonstrated the better understanding between the crop and its management practices. The collected spatial and temporal data via various passive and active sensors has been utilized not only for morphological study but also for monitoring the vegetation moisture content. The paper reviews about the potential studies carried out to investigate the water content in plant to make use in irrigation management. Diverse spectral reflectance indices have been mentioned from which special emphasis on NDWI has been given. It is an index which is used in remote sensing to assess the crop water status and can be utilized in efficient operation of irrigation to improve water use efficiency (WUE) in agriculture. In order to make irrigation practices more efficient by making the lab restricted irrigation scheduling methods like IW:CPE method applicable in regular practice by using remote sensing. This paper firstly identifies areas where researches and techniques have real-world application. Next, it identifies actual issues that remote sensing could address and solve with further research and its related development. All opportunities for managing agricultural water resources effectively to be explored and made successful through precision agriculture. Using the fast, impartial and reliable information offered by remote sensing is a significant difficulty in the field of water resource management.
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An experiment was conducted on mungbean (Vigna radiata L.) during three consecutive years of zaid (2016 to 2018) at Agricultural Research Station, Ummedganj, Kota (Rajasthan). The experiment consisted of 12 treatment combinations including three irrigation regimes (IW/CPE ratio 0.8, 1.0 and 1.2) and four fertility amendments along with foliar spray of bio-regulator (100 % RDF, 100 % RDF + salicylic acid 100 ppm, 125 % RDF + salicylic acid 100 ppm and 150% RDF + salicylic acid 100 ppm) were under taken in split plot design with four replications. The maximum grain yield (930 kg ha-1) was recorded under application of IW/CPE ratio 1.2 over IW/CPE ratio 1.0 and 0.8. Significantly higher WUE (2.04 and 2.03 kg ha-mm-1) and WP (0.204 and 0.203 kg m-3) were recorded under irrigation regime of IW/CPE ratio 1.2 and 1.0 in comparison to IW/CPE ratio 0.8. Significantly higher net return (Rs. 37409/- ha-1) and B:C ratio (1.89) were recorded under irrigation regime of IW/CPE ratio 1.2 over irrigation regimes of IW/CPE ratio 1.0 and 0.8. The maximum grain yield (830 and 840 kg ha-1) was recorded with the application of 125 % RDF + foliar spray of salicylic acid 100 ppm remained on par with 150 % RDF + foliar spray of salicylic acid 100 ppm, but it was found significantly superior over application of over application of 100 % RDF + foliar spray of salicylic acid 100 ppm and 100 % RDF. Significantly higher water use efficiency (2.06 kg ha-mm-1) and water productivity (0.206 kg m-3) were recorded in mungbean with the application of 125 % RDF + foliar spray of salicylic acid 100 ppm over application of 100% RDF + foliar spray of salicylic acid 100 ppm and 100 % RDF in mungbean. Application of 125 % RDF + foliar spray of salicylic acid 100 ppm gave maximum net return (Rs. 31272/- ha-1) and B:C ratio (1.59) over application of 100% RDF + foliar spray of salicylic acid 100 ppm and 100 % RDF.
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A field experiment was conducted during two consecutive Rabi seasons 2020-21 and 2021-22 at Students’ Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh, India. The field experiment allocated three irrigation scheduling namely: I1: two irrigations at CRI (crown root initiation) and Jointing stage, I2: three irrigations at CRI, Jointing and Booting stage and I3: Four irrigations at CRI, Tillering, Booting and Milking stage, two moisture conservation practices viz: M0: without mulching and M1: Organic mulch at the rate of 10 t ha-1 + Kaolin 6% spray and three nutrient management practices viz: N1: 100% Recommended dose of fertilizers (RDF) (150:60:40 kg ha-1 NPK), N2: 85% RDF + Farm yard manure (FYM) @ 5.0 t ha-1 and N3: 75% RDF + FYM @ 10.0 t ha-1. The field experiment was laid out in double split plot design with three replications. On pooled basis of two years experimentation the results indicated that, four irrigations at CRI, Tillering, Booting and Milking stage recorded significantly highest value of crop growth rate (CGR) (13.15 and 19.28 g m-2 day-1 at 30-60 and 60-90 days after sowing (DAS), respectively), grain yield (4381.60 kg ha-1) and consumptive use of water (457.39 mm) while, significantly highest water use efficiency (11.97 kg ha-1 mm) was received under two irrigations at CRI and Jointing stage over the rest of irrigation schedules. In respect of moisture conservation practices, organic mulch @ 10 t ha-1 + Kaolin 6% spray recorded significantly water use efficiency (11.41 kg ha-1 mm) compared to without mulching treatment while, highest consumptive use of water (380.72 mm) was recorded under without mulching. Integration of 85% RDF + FYM @ 5.0 t ha-1 recorded significantly maximum water use efficiency (10.99 kg ha-1 mm) compared to other treatments while, highest consumptive use of water (381.41 mm) was recorded under the treatment of 100% RDF.
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A field experiment was conducted during kharif season of 2017 at Soil Conservation and Water Management Farm of the Chandra Shekhar Azad University of Agriculture and Technology, Kanpur to find out effect of cropping systems and doses of FYM on growth, yield, water use efficiency, splash loss and economics of crops under rainfed condition. The treatments comprised of 4 cropping systems i.e. (i) sole sorghum, 45 cm apart (ii) sole greengram, 45 cm apart (iii) sorghum + greengram (2:1 ratio ) (iv) sorghum + greengram (3:1 ratio) and 3 doses of FYM i.e. (i) without FYM (ii) 10 t ha-1 (iii) 20 t ha-1 were tested in factorial randomized block design with 3 replications. Results revealed that the yield of sorghum and greengram were highest in their sole stands. The yield of sole and intercropped greengram in terms of sorghum equivalent grain yield showed significant variation, whereas sorghum + greengram (2:1 ratio) brought out significantly the highest production as compared to other cropping systems. Moreover, the land equivalent ratio, water use efficiency, gross return and net return were also found to be the highest. Simultaneously, maximum splash loss was observed under sole sorghum and minimum under greengram treatment. Increasing rates of FYM brought out significant improvement in vegetative growth, yield attributes and grain / stover yield, where a dose of 10 t FYM/ha gave best performance in respect of vegetative growth, yield attributes and grain / stover yield. In addition, net return was also noticed higher, but splash loss was lower.
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Comprehension of the bean responses of beans common under to water deficit is an important tool in agricultural planning, like sowing time, and deficit irrigation management strategies. The study aimed to understand the morpho-physiological responses and yield attributes of two common bean genotypes submitted to water stress at different phenological stages. The study was carried out in a greenhouse, in randomized block scheme with five repetitions. To achieve the objectives deficit irrigation of 25% of crop evapotranspiration was practiced during vegetative (DI-V), flowering (DI-F), and pod filling (DI-PF) stages. A non-deficit irrigated (NDI) and deficit irrigated through vegetative to pod filling stages (DI-VP) treatments were added for comparison. The following morphophysiological responses and yield attributes were evaluated: net assimilation of CO2, stomatal conductance, and leaf transpiration, chlorophyll index, number of trifoliate leaves, chlorophyll index, leaf area, number of grains per plant, number of grains per pod, number of pods per plant, the mass of thousand grains, harvest index, and water use efficiency. The beans genotype under DI-V exhibited acclimation, observed by the relative increment with NDI of 195%, 759%, and 231% of net assimilation of CO2, stomatal conductance, and leaf transpiration, respectively. Plants under treatment DI-PF experienced dis-stress and plastic responses as leaf losses and exhaustion of gas exchanges. Treatment DI-V received 11% less water than NDI and exhibited equal yield, resulting in higher water use efficiency. Yield attributes correlations indicated that yield penalty might be related to pods abortion, which not occurred to plants under DI-V.
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Aims: Hopea sangal Korth. is listed as vulnerable species and recently its remnant habitat was rediscovered in the degraded forest near the springs area in East Java. In the forest, the regeneration of the seedling and saplings understory is affected by the heterogeneity in environmental factors especially various light levels due to the canopy gaps. H. sangal is considered a shade-tolerant species, hence the establishment of the seedling in its natural habitat occurs under the closed canopy. This study aimed to understand the Water Use Efficiency (WUE) and Relative Growth Rate (RGR) of Hopea sangal Korth seedling grown in two different levels of tree canopy shades. Study Design: This research was using a completely randomized design, with 9 replications. Place and Duration of Study: This study was conducted in the Purwodadi Botanic Garden, East Java, between March � July. Methodology: We used seedling of H. sangal collected from the field in Pasuruan which were planted in plastic pots and acclimatized to obtain seedling of a similar size. The microclimate was measured weekly using solarimetri and sling psychrometer at 08.00; 10:00; 12:00; 14:00 and 16:00. RGR was measured by harvesting the seedling and whole plant WUE was measured using the gravimetric method. Results: We observed the light level during the periodic opening of the canopy gap was significantly different at a specific time (8-12 am), with the highest light intensity at 10.00 of 333.57 祄ol photon m-2s-1. The canopy shades differences did not affect the WUE of seedling (P = 0.333), meanwhile, there was a significant difference in the seedling RGR (P = 0.025). The seedling that were grown under a higher gap and received higher light intensity periodically during a day had higher RGR than those under a closed canopy. The WUE has a positive relationship with the RGR of seedling (R2 = 0.5; P < 0.05). Conclusions: This study suggested that the H. sangal is one of the shade-tolerant species capable of responding to gap-opening sunlight. The study also showed RGR of the seedling positively correlated with the WUE of plants, indicating that the seedling could use the water supply efficiently to grow rapidly.
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Xanthomonas axonopodis pv. punicae (Xap) is a bacterial pathogen wreaking havoc in pomegranate cultivation. It causes bacterial blight disease dwindling yield and making fruit unfit for consumption. Physiological and histological investigations during host-pathogen interaction are prerequisite to assess the onset of defense mechanism in plants. Therefore, we tried to compare the pomegranate resistant (IC 318734) and highly susceptible (Ruby) genotypes challenged with Xap. The bacterial suspension containing Xap cells of 0.3 OD600 (~106 to 107CFU mL?1) was used for challenge inoculation. Uniformly grown resistant and highly susceptible plants were selected, the surface of leaves was pricked and spray-inoculated with bacterial suspension using native strain IIHR1 (NCBI Gen Bank ID: KT 222897). Simultaneously, the control plants were also sprayed with only distilled water and observed. A total of three replications with five plants per replication were maintained and evaluated under completely randomized design. Physiological investigations were recorded using Portable photosynthesis system (LCpro+, ADC BioScientific limited, UK) for one cycle of disease progression viz., 0, 1, 5, 10, 15 and 20 days after bacterial spray inoculation (DAI). Significant changes in gas exchange parameters were witnessed on pathogen inoculation. Higher reduction in mean percent change of photosynthetic and transpiration rate, instantaneous water use efficiency, internal CO2 content, stomatal conductance and relative water content were noticed in highly susceptible genotype than resistant one. On contrary, an increased percent mean change of intrinsic water use efficiency, carboxylation capacity and lignin was documented in resistant genotype. Relative injury caused due to bacterial infection was found high in highly susceptible genotype than resistant one. Histological investigations in highly susceptible and resistant genotype were studied on 20th day of Xap inoculation using Scanning Electron Microscopy. Highly susceptible genotype exhibited maximum deformed cells, tissues and other visible abnormalities upon Xap inoculation. Thus, this study forms a basis for effective disease management and breeding programmes in pomegranate.
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The coordination between phytohormones regulation, stomatal behaviour (stomatal index and opening/closing) and gas exchange are potent determinants of plant survival under drought stress. However, we found a knowledge gap in the mechanism regulating the fine-tuning of these features during drought. In order to address this we evaluated gas exchange, stomatal behaviour and endogenous phytohormones content in two cotton varieties (LRA-5166 and NBRI-67) differing in drought sensitivity during water deficit conditions. Variety specific differences were recorded in net photosynthesis rate (A), transpiration rate (E) and stomatal conductance (gs) with significantly less decrease in drought tolerant LRA-5166 than drought sensitive NBRI-67. The abscisic acid (ABA) accumulation was significantly increased in LRA-5166 while reduced in NBRI-67 under water deficit, which was accompanied by relatively less reduced 6-benzylaminopurine (6-BAP) level in LRA-5166 than NBRI-67.Thus, improved ABA/6-BAP ratio was observed in both the varieties of cotton. Critically, LRA- 5166 has reduced stomatal index, aperture size and significantly higher A and intrinsic water use efficiency (WUEi), thus higher drought tolerance than NBRI-67. Furthermore, we found that endogenous ABA predominantly maintains the stomatal behaviour and regulates its physiology either by antagonizing 6-BAP or alone to coordinate with water deficit signals. Overall, our findings describe a new insight as to how drought modulates endogenous ABA and 6-BAP homeostasis in cotton leaf and the mechanism of stomatal regulation by ABA and 6-BAP in cotton.
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A wide range of soybean cultivars is available on the market and understanding the physiological response and yield of these materials is fundamental to develop new management systems. Thus, the objective of the present study was to assess ecophysiological parameters and yield of soybean cultivars under field conditions. The experiment was carried out on a farm located in the municipality of Açailândia, Maranhão, Brazil. Three commercial cultivars were used (SC1, SC2 and SC3), and gas exchanges, SPAD index, Fv/Fm, photosynthesis index (PI), instantaneous water use efficiency (WUE) and intrinsic instantaneous of the use of water (iWUE) were assessed during the vegetative (V5) and reproductive (R5) stages. In addition, the biomass and production components were obtained. A randomized complete block design was used, with three cultivars and six replications. SC2 obtained the best mean for the photochemical variables. SC2 was more efficient at both development stages in WUE, but the maximum iWUE values were obtained in SC3. The SC2 cultivar obtained the best responses in the main variables analyzed, resulting in a higher yield.
Subject(s)
Glycine max , Chlorophyll , Efficient Water Use , FluorescenceABSTRACT
The search for genetic materials resistant to adverse weather conditions has been a major focus in studies on species of economic interest. The objective of the present study was to assess the growth and photosynthesis of rubber seedlings clones under two conditions of atmospheric evaporative demand, characterized by fluctuations in temperature (TEMP) and vapor pressure deficit (VPD), associated to two water regimens. Hevea brasiliensis Muell. Arg (RRIM 600 and FX 3864) clones were assessed in two microclimates, at low (TEMP 21.2 ºC and VPD 0.29 Kpa) and high (TEMP 26.9 ºC and VPD 1.49 Kpa) atmospheric evaporative demand, under two water regimens: water deficit and well-watered. Water deficit 50% water availability was sufficient to reduce the net CO2 assimilation rate, leaf area and total chlorophyll of the clones studied that impacted growth in both microclimates. The effects of water deficit on growth and net carbon assimilation rate were intensified under high atmospheric evaporative demand. However, when comparing the two clones studied, RRIM 600 showed greater growth and photosynthesis without water restriction. The FX 3864 clone, despite the high CO2 assimilation values under high atmospheric demand and without water restriction, showed a reduced growth. The results of this study form an important basis for the selection of genotypes with the potential to develop in adverse climatic conditions. In this sense, the RRIM 600 genotype is recommended as a promising material that would best adapt under adverse climatic conditions.
Subject(s)
Photosynthesis , Rubber , Hevea/growth & development , Efficient Water UseABSTRACT
Objective: The moisture content in the soil directly affects the yield and quality of Panax notoginseng, especially at the age of three years old. However, the suitable moisture for the growth of P. notoginseng is unknown. In this study, the effects of different soil moisture on the growth of P. notoginseng were studied. Methods: Four different water treatments (0.45 field capacity (FC), 0.60 FC, 0.70 FC, and 0.85 FC) were set up in Shilin County, Yunnan Province, China. The water consumption and daily dynamic of water consumption were determined daily (from April 21 to October 18, 2012), and the daily dynamic of water consumption under different weather conditions (sunny and rainy) was determined. The transpiration coefficient and water use efficiency were calculated through dry matter accumulation and total water consumption. Accumulation of saponins of roots of P. notoginseng were analyzed by HPLC after treated, and the soil moisture content suitable for the growth of P. notoginseng was estimated by regression fitting of the active ingredient accumulation and the soil moisture content. Results: The water consumption of 0.85 FC, 0.70 FC, 0.60 FC and 0.45 FC were 2.89, 3.68, 3.37 and 2.73 kg/plant per day, respectively. The water consumption of P. notoginseng from June to August was greater than other months. The daily dynamic of water consumption on sunny days and sunny days after rain showed a “double peak” feature, and it showed a “single peak” feature on rainy days. The water uses efficiency (WUE) of 0.85 FC, 0.70 FC, 0.60 FC and 0.45 FC were 2.51, 3.32, 4.59, 3.39 gDW/kg H
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HIGHLIGHTS Azospirillum brasilense stimulates root growth in maize under water deficit. Maize inoculated with A. brasilense shows greater photosynthesis under drought conditions. Under water deficit, maize plants inoculated with A. brasilense showed greater water use efficiency (WUE).
Abstract The objective of this study was to evaluate the gas exchange, root morphology and nutrient concentration in maize plants inoculated with A. brasilense under two water conditions. The experiments were carried out in a greenhouse, one under irrigation and the other under water deficit. The treatments consisted of four A. brasilense inoculants (control (without inoculation), Az1 (CMS 7 + 26), Az2 (CMS 11 + 26) and Az3 (CMS 26 +42). At the V6 plant stage, water stress was imposed on maize plants for 15 days. The phytotechnical characteristics, gas exchange, root morphology, root dry matter and macronutrient analysis were evaluated after 15 days of water deficit imposition. The water deficit caused a reduction in the development of maize plants. The presence of A. brasilense Az1 under the same condition yielded higher photosynthesis, carboxylation efficiency, water use efficiency, and greater soil exploration with increased length, surface area and root volume of plants. Inoculation by A. brasilense increased root system volume by an average of 40 and 47% under irrigation and water deficit, respectively, when compared to non-inoculated plants. The inoculant Az1 attenuated the deleterious effects caused by drought and yielded the best growth of the root system, resulting in the tolerance of maize plants to water deficit.