Irrigation Water Regimes Research Articles

How far can the interactive effects of continuous deficit irrigation and foliar iron fertilization improve the physiological and agronomic status of soybeans grown in calcareous soils under arid climate conditions?

Water and iron are crucial elements for soybean growth and development, particularly in calcareous soils and arid climatic conditions. The aim of this study was to improve iron and water use efficiency and enhance soybean resilience to water scarcity and iron deficiency. So, the effect of 16 treatments; 4 deficit irrigation water regimes (25, 50, 75 and 100 % crop water requirements (CWR)) combined to 4 foliar iron gradual concentrations (F0=0, F1=1, F2=3 and F3=5 g/L of FeSO4) applied at 3–4 leaves, at the beginning of flowering and at the end of flowering; was investigated in this split plot experiment with 4 replicates. Our results showed that supplying iron and water to plants can improve chlorophyll florescence a, chlorophyll content, stomatal conductance, yield, iron uptake, and protein content. Determining the optimal combination of deficit irrigation treatment and gradual iron sulfate concentrations for soybean is an alternative to save water and improve growth parameters. In our manuscript, we can conclude that 75 % CWR × F2 is the best combination of the two factors that led to the same biological yield as 100 % CWR. Consequently, we can say that applying F2 as a foliar iron concentration led to an economy of 25 % of the soybean crop water requirement by ensuring an adequate supply of soluble iron, facilitating root uptake, promoting protein synthesis, enhancing chlorophyll formation, and supporting overall nutrient uptake and metabolism.

Vetiver forage yield and nutritive value affected by water irrigation regimes and plant density under Mediterranean climate conditions

Vetiver forage yield and nutritive value affected by water irrigation regimes and plant density under Mediterranean climate conditions

Effect of plastic film mulch and irrigation water regimes on soil temperature pattern, plant growth and water productivity of maize

In arid and semi-arid climate, combining different plastic film mulches and irrigation water regimes may be lead to enhance of grain yield and water use efficiency (WUE) with water saving. For the optimum grain yield of maize crop, soil water content and temperature, and irrigation water use efficiency are still not well understood in the climate of Sindh, Pakistan. Therefore, the aim of this study was to examine the soil moisture pattern, soil temperature, yield and WUE under interaction of mulching and soil water status. This field experiment was conducted at the station of department of Irrigation and Drainage during cropping seasons 2021–22. In field trial involved three mulching modes (black and white film, without film) and two irrigation water regimes (sufficiently and severely water stress). The results showed that across the irrigation water regimes treatments, without mulched treatment plants depressed both moisture status and temperature of the soil, nonetheless, the decrease soil water status was more pronounced compared with the reduction in soil temperature. Plant dry biomass was improved when mulching with black plastic film as exemplified by the increased plant height, indicating the increased plant biomass. However, across the mulching treatments, by improving the plant micro-climate condition by black colored plastic film mulching increased significantly grain yield by 17–47% and WUE by 16–46% because less soil water depletion as compared with white plastic mulch and without mulch treatments, respectively, causing the serious waste of water resources. Across the water regimes, sufficiently water stressed condition (80% of soil water holding capacity, SWHC) could significantly enhance grain yield by 17.4% and WUE by 8% as compared to moderately water stressed condition (50% of SWHC). Mulching with black colored plastic film is suggested for maize in terms of high grain yield and water use efficiency with a minor dry biomass reduction.

Shading effects in agrivoltaic systems can make the difference in boosting food security in climate change

Photovoltaic (PV) systems play an important role in the sustainable energy transition, but their impact on food security is ambiguous due to the shift in land use from agriculture to energy production. Currently, agrivoltaic is emerging as an alternative sustainable energy source that optimises multifunctional land use by simultaneously supporting electricity generation and agricultural activities. While many studies have extolled the benefits of shade provided by agrivoltaic on crop water balance and evapotranspiration, plant ecological adaptation, such as Shade Avoidance Syndrome (SAS), and its implications for food security remain relatively unexplored. In this context, we have investigated the influence of a panel-generated shadow on chicory crop production in terms of plant biomass yield and its quality for human health under different water irrigation regimes. For each chicory plant, fresh weight and leaf dimensions were measured to estimate edible biomass, while leaf water content, chlorophylls a and b, carotenoids, metabolite profile and antioxidant capacity were evaluated to assess food quality. Our results show that the shading system has a remarkable capacity to increase edible chicory biomass production compared to full sunlight conditions of 69% and 23%, respectively for high water supply and low water supply, and greater capacity to promote pollination ecosystem services. The shade, provided by a well-designed agrivoltaic system, improves SAS and directly increase yield without altering food quality. Thus, agrivoltaic systems can combine renewable energy strategies with food security, while enhancing ecosystem services for human well-being.

Drought Priming and Subsequent Irrigation Water Regimes Enhanced Grain Yield and Water Productivity of Wheat Crop

The most important factor impacting wheat production is water stress that occurs during the reproductive growth stage. Therefore, the plant responses and water productivity as affected by drought priming were investigated during Rabi seasons 2021 and 2022. The field trials were conducted in the research field of the Department of Irrigation and Drainage, Faculty of Agricultural Engineering, Sindh Agriculture University, Tandojam. The Hamal-BNS wheat variety was subjected to differing irrigation water regime levels (40%, 50% and 60% of soil water holding capacity, SWHC) after being subjected to drought priming, irrigation water recovery (water closure period) and drought priming. There were six treatments: (1) DPP-40 (drought priming plants at 40% of SWHC), (2) DPP-50, (3) DPP-60, (4) CTP-40 (controlled treated plants at 40% of SWHC), (5) CTP-50 and (6) CTP-60. During the experiment period, soil moisture content was significantly affected by the different treatments at various growth stages of wheat. The results indicated that winter wheat pre-exposed to drought priming attained a stress imprint that improved the subsequent deficit water levels which occurred during the later plant growth stage as demonstrated by the progress of test weight, grain yield, plant level water use efficiency and irrigation water use efficiency as well as relative yield compared to CTP-50 (control treatment). Under the irrigation water regime levels during the post-anthesis period, primed wheat plants sustained grain yield and higher relative yield than wheat plants without priming due to the better irrigation water regime for drought-primed wheat plants. Similarly, primed wheat plants consumed 18.3% less irrigation water as compared to non-primed plants, which significantly increased plant level WUE and irrigation WUE and decreased dry biomass and root development of drought-primed wheat plants. Therefore, to conserve fresh water for other field crops and increase water productivity in the Sindh province, it is recommended that drought priming is used during the early growth period of wheat plants as a successful irrigation method.

Effect of different irrigation water regimes on water productivity of wheat crop

Effect of different irrigation water regimes on water productivity of wheat crop

Nitrogen application rates influence on yield and water productivity of quinoa under saline irrigation water regimes and saline water table

There are areas with high saline water and saline irrigation water in Iran that may be used for quinoa cultivation. In these conditions, proper saline irrigation water regimes and nitrogen application should be determined and used. Therefore, the aim of this experiment is to investigate the effect of different saline irrigation water regimes (100, 75 and 50% of full irrigation, FI) and nitrogen application rates (0, 100, 200 and 300 kg ha−1) on growth and yield of quinoa with water table depth of 0.8 m, salinity of irrigation water and water table of 20 dS m−1. The irrigation of 75% FI and 50% FI decreased the applied water by 19 and 38%, respectively. Further, there was no reducing effect of irrigation water regimes in seed and shoot dry matter yield. Furthermore, groundwater contribution (GWC) increased significantly by 8 and 18% in 75%FI and 50%FI compared with that obtained in full irrigation, and resulted in no extreme water stress under high water table depth (0.8 m). Increasing application of nitrogen fertilizer significantly increased the yield components, ETc and GWC. In addition, reducing irrigation water did not show a significant decrease in water use efficiency (WUE) in high water table depth. However, water productivity increased significantly by decreasing irrigation water. It is concluded that under deficit irrigation, high water table depth could be a valuable source of water supply to meet quinoa water requirements. Moreover, application of nitrogen fertilizer at all levels significantly increased water use efficiency and water productivity.

Handheld NDVI sensor-based rice productivity assessment under combinations of fertilizer soil amendment and irrigation water management in lower Moshi irrigation scheme, North Tanzania

Handheld optical sensor was used to measure canopy reflectance at red region (656 nm) and near-infrared region (774 nm) to generate NDVI data for monitoring rice productivity under soil amendment with combinations of fertilizers at two levels of water regime in smallholder Irrigation Scheme, in Lower Moshi, North Tanzania. The study was carried out in an experimental design which consisted of two irrigation water levels (flooding and system of rice intensification) with multi-nutrients (NPK) and single nutrient (urea) application replicated three times in a randomized complete block design. Flood irrigation water was applied at 7 cm height throughout the growing season, while SRI treatment irrigation water was applied at 4 cm height under alternate wetting and drying conditions. The annual rates of fertilizers applied was 120 kg N/ha, 20 kg P/ha, and 25 kg K/ha. The variety SARO-5 was used in this experiment. Simple correlation coefficient (r) was used to measure the degree of association between field crop performance parameters (plant height, number of tillers, biomass, yield) and NDVI across growth stages and three positions of the sensor above the canopy in the tested fertilizer combinations and water regimes. Results show that at any given fertiliser combinations and water levels, there was no significant correlation between plant height and NDVI except for the plant height at a vegetative stage for 0.6 m above the crop canopy and booting stage at 0.3 m and 0.6 m above the canopy, respectively (P < 0.05). A good correlation was also observed between NDVI at booting and full booting stage regardless of the position of the sensor above the canopy and the number of tillers at full booting growth stage (P < 0.05). A significant relationship was observed between rice grain yield and NDVI at the vegetative, booting, and full booting stage. The simple linear regression models explained only slightly < 30% of the yield predictions by NDVI at the early stage of the crop growth, decreasing gradually to 5% at the full booting growth stage. Results demonstrate a positive linear relationship between rice grain yield and NDVI for the tested soil fertiliser amendments and irrigation water regimes. Thus, we conclude that handheld NDVI-based sensor can be used in smallholder rice yield predictions for optimising soil fertiliser use and irrigation water management. This allows future multi-functional land management within the soil–water-food nexus.

Elevated CO2 enhances rice root growth under alternate wetting and drying irrigation by involving ABA response: Evidence from the seedling stage

AbstractThe atmospheric CO2 enrichment can seriously affect rice root growth. Alternate wetting and drying (AWD) irrigation, which can also increase root growth, is a widely promoted water‐saving technology for future climate, yet how elevated CO2 (eCO2) influences rice root growth under AWD remains unclear. In the present study, we examined the root growth of Yangdao 6 (YD 6) and Koshihikari (KOS) cultured under different water irrigation regimes (well‐watered and AWD) and CO2 concentration (400 and 800 ppm). AWD reduced shoot dry weight of KOS compared with WW under ambient CO2 (400 ppm, aCO2), while the shoot dry weight of KOS showed no difference between WW and AWD treatments under eCO2. Additional, under aCO2, AWD did not affect the exhibited similar root dry weight, length, total surface area, and volume of YD 6 and KOS relative to WW. However, under eCO2, AWD significantly promoted the root dry weight, root length, total root surface area, and root volume of YD 6 and KOS. Furthermore, root ABA content of YD 6 and KOS was significantly higher under AWD than under WW. Then, the OsNCED3 (a key gene for ABA biosynthesis) RNAi lines were used to check the role of ABA in root growth under eCO2 with AWD conditions. The results showed that AWD increased the ABA content and root parameters of WT but not the OsNCED3 RNAi lines under eCO2. Overall, the results suggest that eCO2 can improve rice root growth under AWD by involving root ABA, which contributes to the understanding of water‐saving irrigation on rice in the future climate.

Vegetative growth, yield, and crop water productivity response to different irrigation regimes in high density walnut orchards (Juglans regia L.) in a semi-arid environment in Argentina

The area dedicated to walnut orchards has recently expanded in central-western Argentina. Nevertheless, studies on crop water demand are scarce and fundamental in semi-arid environments. This work aims to evaluate the effects on stem water potential (SWP) and stomatal conductance (gs), vegetative growth (trunk cross-sectional area, canopy volume, and canopy porosity), and water productivity in terms of yield of four water irrigation regimes T50, T75, T100, and T125. The plants were irrigated at 50%, 75%, 100%, and 125%, of crop evapotranspiration, respectively over two consecutive seasons (2018–2019 and 2019–2020). The experiment was carried out in a young walnut orchard cv. Chandler in a semiarid environment in La Rioja province, Argentina. SWP and gs had similar seasonal behavior in both seasons. T100 SWP remained between 0.5 and 0.8 MPa, like T75, while T50 reached minimum values of − 1.0 MPa. Stomatal conductance was less responsive than SWP to water deficit, showing significant differences only at 100 days after bloom. Vegetative growth and yield components did not differ among treatments. Compared to T100 and T50, crop water productivity (CWP) increased from 4.30 to 5.29 dry yield mm−1 ha−1 in 2018–2019 and from 5.25 to 7.28 kg dry yield mm−1 ha−1 in 2019–2020; while T75 CWP did not differ from the CWP of T100. Irrigation doses greater than crop requirements (T125) have no effect on yield if compared with T100, and in terms of the water productivity function, irrigation at 90% of T100 would have allowed for maximum productivity in both seasons.

Changes in Essential Oil Composition, Polyphenolic Compounds and Antioxidant Capacity of Ajowan (Trachyspermum ammi L.) Populations in Response to Water Deficit.

Ajowan (Trachyspermum ammi L.) is considered a valuable spice plant with a high thymol content. Seed yield, essential oil constituents, polyphenolic composition, and antioxidant capacity of ajowan (Trachyspermum ammi L.) populations were evaluated in three (normal, moderate, and severe) water irrigation regimes. The highest essential oil content (5.55%) was obtained under normal condition in the Yazd population. However, both essential oil and seed yield showed significant reductions as a result of water stress. According to gas chromatography–mass spectrometry (GC–MS) analysis, thymol (61.44%), γ-terpinene (26.96%), and p-cymene (20.32%) were identified as the major components of the oil. The highest (89.01%) and the lowest (37.54%) thymol contents were in Farsmar and Hamadan populations in severe stress condition, respectively. Based on HPLC analysis, chlorogenic (3.75–47.35 mg/100 g), caffeic (13.2–40.10 mg/100 g), and ferulic acid (11.25–40.10 mg/100 g) were identified as the major phenolic acids, while rutin was determined as the major flavonoid (11.741–20.123 mg/100 g). Moreover, total phenolic and flavonoid contents were elevated under drought stress treatment, while antioxidants responded inconsistently to stress based on two model systems. Overall, the Yazd population exhibited a superior response to water stress, as evidenced by its less reduced thymol and oil yield content, while Arak and Khormo had the highest accumulation of polyphenolic compounds.

Effect of water regime and palm mass on cultivation of green pepper

In this study, we aimed to evaluate the agronomic behavior of green peppers subjected to different water regimes and masses of forage cactus incorporated into sandy soil in a tropical climate. The treatments were organized in a 4 × 4 factorial scheme, with water regimes and forage cactus masses incorporated into the soil in a randomized block design. The results allowed us to observe an isolated significant difference for each factor studied. The water regime RH=100% of the vessel capacity (VC) and mass density of 100 g dm−3 of forage cactus incorporated into the soil positively affected the plant height variables, stem diameter, total chlorophyll, and water potential; specifically, these treatments were superior to soil with water restriction and without the addition of forage palm by 63%, 15%, 61%, and 71%, and 87%, 85%, 81%, and 63%, respectively. The doses of soil conditioner masses containing 0 g dm−3 and 100 g dm−3 of palm in the soil showed the best results for the number of fruits (3.25 and 2.00 fruits), number of commercial fruits (2.0 and 1.5 fruits), and fruit length (88.87 mm and 95.92 mm). Forage cactus mass of 100 g dm−1 of Quartzarenic Neosol and 100% VC irrigation water regime is the most recommended treatment for the protected cultivation of green pepper, as it positively influences productivity and the morphophysiological characteristics of the crop.

Effect of Drought Stress on Physio-biochemical Traits and Secondary Metabolites Production in the Woody Species Pinus Halepensis Mill. At a Juvenile Development Stage

ABSTRACT The characterization of the drought stress responses of plants is essential to understand the interactions of these effects with key life processes, such as growth and reproduction. The capability of plants to respond to abiotic stress is associated with their plasticity as well as the adaptableness of plant traits to fluctuating bioclimatic conditions. In this study, the response of Pinus halepensis seedlings to the different water irrigation regimes was assessed based on various ecophysiological, biochemical, and metabolic traits. This approach aims to identify different traits capable of predicting the ability of formerly uncharacterized seedlings to cope with drought stress. The obtained results revealed that drought stress affects the vital metabolic processes in Aleppo pine plants, such as transpiration, photosynthesis, and respiration at their early development stage. These variations were accompanied by changes in chlorophyll pigment contents and an accumulation of organic solutes (sugar and proline). Both drought stress levels induced an increase over the control of the amounts of total secondary metabolites and essential oil contents. These findings are of particular interest in the comprehension of seedlings response to drought stress which provides valuable background knowledge for the success of reforestation programs based on this woody species.

Effects of Automated Irrigation Systems and Water Regimes on Soil Properties, Water Productivity, Yield and Fruit Quality of Date Palm

Applications of modern micro-irrigation methods are inevitable for optimum water use due to the limitations imposed by irrigation water resource scarcity. Regardless of water shortages and associated challenges in dry areas, the irrigation of date palm trees consumes an excessive quantity of water annually using conventional irrigation methods. Therefore, the present study was designed to evaluate the effects of modern surface and subsurface micro-irrigation systems, i.e., subsurface drip irrigation (SSDI), controlled surface irrigation (CSI), and surface drip-irrigation methods (SDI), with different irrigation water regimes, i.e., 50%, 75%, and 100% irrigation water requirements (IWRs), on the yield and fruit quality of date palms (cv. Khalas) and water conservation in the dryland region of Al-Ahsa, Saudi Arabia. The effects of three irrigation methods and IWRs were studied on macronutrients and soil chemical properties at three depths (0–30, 30–60, and 60–90 cm), as well as on water productivity, yield, and the fruit quality of date palms. The study was carried out over two years and was designed using a two-factorial randomized complete block design (RCBD) with nine replications. The results indicated that electrical conductivity (EC) increased as the depth of the soil increased. The soil chemical properties did not change much in all experimental treatments, while soil pH values decreased with the soil depth from 0–30 to 60–90 cm. Although the maximum fruit yield (96.62 kg palm−1) was recorded when 100% irrigation water was applied in the SSDI system, other treatment combinations, such as SDI at 100% IWR (84.86 kg palm−1), SSDI at 75% IWR (84.84 kg palm−1), and CSI at 100% IWR (83.86 kg palm−1) behaved alike and showed promising results. Similarly, the highest irrigation water productivity (2.11 kg m−3) was observed in the SSDI system at 50% IWR, followed by the SSDI at 75% IWR (1.64 kg m−3) and 100% IWR (1.40 kg m−3). Fruit quality attributes were also promoted with the SSDI system at 75% IWR. Hence, the SSDI method at 75% IWR appeared to be an optimal choice for date palm irrigation in arid areas due to its positive impact on water conservation and fruit characteristics without affecting soil chemical properties.

Evaluation of chemical composition of roots of three sugar beets varieties growing under different water deficit and harvesting dates in Upper Egypt

Field experiments were carried out at Shandaweel Agricultural Research Station, Sohag, Egypt to study the effects of deficit irrigation and harvesting date chemical composition of three sugar beet varieties. A split block design with three replications was used. Main blokes were assigned to three irrigation water regimes (100%, 85%, and 70% of water requirement). The sub blot was occupied by three harvesting dates (180, 195 and 210 days). Sub- sub plots comprised three sugar beet varieties namely (RAVEL, SV1841and SA1686). Results indicated that reducing water supply reduced alpha - amino N present in the second season, Na present in the second season, and K present and sugar lost to molasses, but increased sucrose present, extractable present, QZ present, purity present, extractability present. Increasing harvesting date increased K present, sucrose present, extractable present, QZ present, purity present, extractability present but reduced alpha - amino N present, Na present and sugar lost to molasses in the second season. Sucrose present, extractable present, QZ present purity present and extractability present of RAVEL and SA1686 varieties were almost comparable but higher than those of SV1841 variety.

Utilization of cactus pear fruits’ pulp planted under severe drought conditions as source of natural pigments and antioxidant in cake making

Cactus pear is a dominant crop to arid lands with high nutritional value. Its fruits are used in food processing as add value to food products. The current study planted cactus pear under three irrigation regimes (T1, T2, and T3) where two of them (T2 and T3) implicated severe deficit irrigation conditions on the crop. The relationship between applied irrigation water regimes and fruit physical and chemical properties including antioxidants, pigment and vitamin C content was studied. The study also aimed to utilize cactus pear’s pulp (CPP), as additive value, in the processing of wheat flour cupcake. Samples of cupcake were made by adding 20%, 40%, 60% and 80% CPP based on wheat flour weight. Fruits obtained under T2 and T3 treatments had higher color concentration than T1. T2 irrigation regime yielded higher content of total phenolic and flavonoid content (TPC and TFC) than those produced under T3 and T1. Antioxidant activity was the highest in T2. Thus, fruit pulp obtained from T2 was selected for cupcake making. The content of soluble solids was ⁓18 Brix in all treatments. VitC. was significantly higher (P≤0.05) in T3 (56.04 g AA/kg) than T1 (55.42 g AA/kg) and T2 (51.01 AA/kg). The content of betacyanins in T1 was higher (0.47 mg100mg dry weight) in fruits pulp than T2 and T3 (0.44 and 0.54 mg100mg dry weight). Sensory evaluation showed that fortification with 60% cactus pear pulp had the best sensory characteristics meanwhile cupcakes fortified with 80% cactus pear pulp was not acceptable.

Yield Performance and Physiological Response of a Maize Early Hybrid Grown in Tunnel and Open Air under Different Water Regimes

Climate change is one of the most important and studied phenomena of our age and it can have a deep impact on agriculture. Mediterranean countries are and will continue to be strongly affected by changing environmental factors, including lack of precipitation and prolonged heatwaves. The current study aimed to assess the adaptability of an early maize hybrid grown in two temperature conditions and subjected to different irrigation water regimes. The experimental design was a randomized complete-block design with two different temperature conditions: (i) ordinary temperature in open field (OF) and (ii) high temperature (about 3 °C higher than the current condition) under a poly-ethylene tunnel (PE). In both environments, five irrigation level treatments were applied: 100% (DI100), 75% (DI75), 50% (DI50), 25% (DI25), and 0% restoration of water lost by evapotranspiration (DI0). The responses of maize plants were assessed in terms of yield, nitrogen content determination, nitrogen use efficiency, leaf gas exchanges, and leaf water potential measurements. In both conditions, yield and its components linearly decreased as the irrigation water amount reduced, and even the DI0 plants did not produce. Notably, the PE-DI100 treatment had a significantly higher yield than the corresponding treatment in the open air (9.9 vs. 8.5 t ha−1), due mainly to the increased number of ears per square meter (13 vs. 11 m2, respectively). Though, as far as it concerns physiological parameters, a significant effect of environmental conditions was found, with values significantly lower under the protected environment, compared to the plants in the open field. Considering our results, it can be assumed that correct management of amount and time intervals of irrigation could adapt the maize to future climate change.

Introgression of QTLs for Drought Tolerance into Farmers’ Preferred Sorghum Varieties

Sorghum is a major staple food crop for the people in semi-arid areas of Africa and Asia. Post-flowering drought is a global constraint of sorghum production. The study aimed to improve stay-green (STG) characteristics of farmer-preferred sorghum varieties in Tanzania using marker-assisted backcrossing. A total of 752 individuals representing five BC2F1 populations and their parents were genotyped using previously reported KASP markers linked with STG 3A and STG 3B quantitative trait loci (QTL). In the BC2F1 populations, the maximum number of individuals with heterozygous alleles were observed in S35*Pato background (37) whereas only seven individuals derived from the B35*Wahi parents’ background contained heterozygous alleles. Of the 30 single nucleotide polymorphism (SNP) markers, favourable alleles were observed at 18 loci in BC2F1 populations. In the BC2F1 generation, the highest (0.127 kg/panicle) grain yield was observed in the B35*NACO Mtama 1 background population. The genotypic analysis revealed the presence of favourable alleles in homozygous conditions at markers loci associated with STG 3A and STG 3B QTLs in BC2F3 populations, suggesting successful introgression of STG QTLs from the donor parents to the recurrent parents. Across water irrigation regimes, the highest (0.068 kg/panicle) mean grain weight was observed in the genotype NA316C. Therefore, our study demonstrated the utility of marker-assisted backcrossing for drought tolerance improvement of locally adapted sorghum varieties in Africa.

Genetics components of rice root architecture and carbon isotopic fractionation parameters: a tracer for breeding in a water-saving irrigation management

Phenotyping is the major bottleneck in the effort to develop varieties of rice (Oryza sativa L.) suitable for growing under a water-saving irrigation management, such as alternate wetting and drying irrigation techniques (AWD). To analyze if the genotypic variability for carbon isotope discrimination (CID) in rice leaves could be used as a relatively high-throughput tracer to early select superior genotypes highlighting improved root architecture traits when submitted to AWD, a set of twenty varieties grown under semi-natural conditions were submitted to two water irrigation regimes, continuous flooding (CF) and AWD cycles. Coefficients of genetic variance (π2g) obtained for root architecture, micro-morphological and physiological traits were significant for all of them regardless of the adopted irrigation system, except to mean root diameter. The three significant principal components (PCs) with eigenvalue > 1, explain most of the total variation across cycles and water regimes. For most of analyzed traits, the values of heritability coefficients were higher regardless of adopted irrigation management and trait category; for CID, the magnitudes of broad heritability at an individual level (greater than 0.80) were similar in the two irrigation techniques, evidencing that the success of the selection is independent of irrigation management. The higher CID values after three AWD cycles are associated with varieties with higher total root length and volume. To our knowledge, this is the first study demonstrating the potential application of CID as a tracer to select root architecture traits in rice when water-saving irrigation management is of concern.

Influence of compost and canal clay scouring on sandy soil properties and wheat productivity under Irrigation water regime

Influence of compost and canal clay scouring on sandy soil properties and wheat productivity under Irrigation water regime