Effects Of Different Water Regimes Research Articles

Irrigation regimes modulate non-structural carbohydrate remobilization and improve grain filling in rice (Oryza sativa L.) by regulating starch metabolism

Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to starch metabolism in rice stems and grains, and the microstructures related to carbohydrate accumulation and transportation to investigate the effects of different water regimes on grain filling. Two ‘super’ rice cultivars were grown under two irrigation regimes of well-watered (WW) and alternate wetting and moderate soil drying (AWMD). Compared with the WW treatment, the activities of ADP glucose pyrophosphorylase (AGPase), starch synthase (StSase) and starch branching enzyme (SBE), and the accumulation of non-structural carbohydrates (NSCs) in the stems before heading were significantly improved, and more starch granules were stored in the stems in the AWMD treatment. After heading, the activities of α-amylase, β-amylase, sucrose phosphate synthase (SPS) and sucrose synthase in the synthetic direction (SSs) were increased in the stems to promote the remobilization of NSCs for grain filling under AWMD. During grain filling, the enzymatic activities of sucrose synthase in the cleavage direction (SSc), AGPase, StSase and SBE in the inferior spikelets were increased, which promoted grain filling, especially for the inferior spikelets under AWMD. However, there were no significant differences in vascular microstructures. The grain yield and grain weight could be improved by 13.1 and 7.5%, respectively, by optimizing of the irrigation regime. We concluded that the low activities of key enzymes in carbon metabolism is the key limitation for the poor grain filling, as opposed to the vascular microstructures, and AWMD can increase the amount of NSC accumulation in the stems before heading, improve the utilization rate of NSCs after heading, and increase the grain filling, especially in the inferior spikelets, by altering the activities of key enzymes in carbon metabolism.

Vegetative Growth Dynamic and Its Impact on the Flowering Intensity of the Following Season Depend on Water Availability and Bearing Status of the Olive Tree

A sufficient and mature vegetative growth is an essential condition for production in the following season and consequently affects the alternate bearing (AB) behavior. However, little is known about its interaction with the crop load and water supply. Herein, we studied the effect of different water regimes and bearing status on the vegetative intensity and flush and its consequence on the flowering parameters of the following season. Rainfed (RF) and fully irrigated (FI) treatments were applied for bearing (ON) and non-bearing (OFF) trees of the ‘Zalmati’ olive orchard in south Tunisia during 2018. The water deficit condition (RF) and the high crop load (ON) have caused a similar decrease in the total node number and shoots length by about 65%. Furthermore, the flowering parameters in 2019, especially the percentage of floral buds (i.e., floral induction intensity), were differentially affected by water supply according to the bearing status of the previous season. FI reduced the percentage of floral buds in 2019 by about 37% for OFF trees, while it increased it by more than four times for the ON trees. Concerning the growth flush, the second (i.e., autumnal) flush seems to respond better to water supply than the first (i.e., spring) one, for both vegetative and flowering parameters. The second flush of growth provided 28% of the total vegetative growth but contributed about 35% to the total number of floral buds for RF OFF trees. Besides, FI makes the first and the second flushes contribute equally to total vegetative growth and to the flowering parameters of the following season. On the other hand, the bearing status of the trees does not affect the contribution of each flush to the total vegetative growth.

Effect of Deficit Irrigation on Yield Components and Chemical Composition of Albariño Grapes Grown in Galicia, NW Spain

In the context of climate change, water management is crucial for controlling the reproductive growth and quality of grapes. In this study, we aim to determine the effects of different water regimes on the yield components and chemical composition of grape Vitis vinifera Albariño grown in Galicia. Four treatments were tested in the trial: rainfed (T0), irrigated at 30% of ETo from veraison to harvest (T1), from pea-size to harvest (T2), and throughout the whole vegetative cycle (T6). To analyse the effects of irrigation, measures of stem water potential (Ψstem) were obtained fortnightly, from flowering to harvest. During the harvest, the average weight per bunch and the number of bunch and yield per vine were determined. In addition, the Ravaz index was also calculated. The grapes from each experimental treatment were subjected to chemical (OIV methods) and volatile composition (GC-MS) analyses. The results indicated a greater yield in the T0 group. The lowest yield was observed for T2 over the three years of the study. The results also showed a stronger influence of year than treatment on Albariño must include chemical composition parameters. Treatment affected malic acid, total acidity, free amino acids (FAN), and assimilable yeast nitrogen (YAN); meanwhile, of the volatile chemical groups analysed, esters, acetates, and volatile acids were affected by the treatment, while the season affected all chemical families of volatile compounds, with the exception of C6 compounds. The interaction effect of Tr × Y was observed on esters, acetates, and total volatile concentration. In the contrast analysis (p < 0.05), we observed increases in alcohols and terpenes in T6 vs. T2; however, esters and acetates were increased under rainfed treatment (T0) vs. T6.

Effect of different water regimes and nitrogen applications on the growth, yield, essential oil content, and quality parameters of the oil rose (Rosa damascena Mill.)

Oil rose (Rosa damascena Mill.) is a great important aromatic and medicinal plant widely used in cosmetics, food processing, pharmaceuticals, and agrochemical industries. Water supply and nutrition are vital for plant growth and yield. Water stress causes plant growth, development, and yield loss at different levels. This study was conducted to investigate the effect of different water and nitrogen levels (N) on growth, yield, and quality parameters and determine the chemical composition of oil rose through gas chromatography coupled with mass spectrometry (GC/MS) analysis. The fieldwork for this research was conducted from March 2014 to June 2018. According to the results of study treatments, the highest fresh flower yield per plant was determined with the I0.50, 80 kg ha−1 treatment. In 2017 and 2018, as fertilizer level increased and irrigation level decreased, fresh flower yield, oil yield per plant, plant height, number of branches in plant, and leaf area values decreased. However, there was little tradeoff between reductions in applied water and fresh flower yield. Furthermore, the GC-MS results reveal little change in essential oil quality as water stress increases with diminished applied water. The yield response and essential oil quality are the direct result of the relatively invariant WUE.

Water Regime Monitoring of the Royal Walnut (Juglans regia L.) Using Sap Flow and Dendrometric Measurements.

Changes in the distribution of annual rainfall totals, together with the increase in temperature over the last 40 years, are causing more frequent periods of drought, and plants are more often exposed to water stress. The aim of this study was to monitor the effect of different water regimes (irrigated and non-irrigated) of individuals of walnut tree (Juglans regia L.) in a private orchard located in the West of Slovakia. Our research was focused on dendrometric and sap flow measurements in the period from 28 March to 2 June 2019. The results showed differences in the sap flow of walnut trees during the budbreak period: when trees were irrigated, sap flow in the diurnal cycle was around 130 g·h−1 (20.48%), higher than in the non-irrigated treatment. Dendrometric differences between the irrigated and non-irrigated treatments were not significant. The sap flow data in the flowering period of the irrigated variant were slightly higher at 150 g·h−1 (35.62%) than non-irrigated. Dendrometric differences were more significant when the difference between the variants was more than 1.5 mm. Continuation of this research and analysis of the data obtained in the coming years will allow us to evaluate the effects of the environment on fruit trees in the long term.

Quinoa for the Brazilian Cerrado: Agronomic Characteristics of Elite Genotypes under Different Water Regimes

Quinoa stands out as an excellent crop in the Cerrado region for cultivation in the off-season or irrigated winter season. Here, we tested the effects of different water regimes on the agronomic characteristics, physiology, and grain quality of different elite quinoa genotypes under field conditions. The experiment was conducted under field conditions at Embrapa Cerrados (Planaltina, DF, Brazil). The experimental design was in randomized blocks, in a split-plot scheme, with four replications. The plots were composed of 18 quinoa genotypes and modified BRS Piabiru (the currently used genotype), and the split-plots were divided into 4 different water regimes. The following variables were evaluated: productivity and productivity per unit of applied water (PUAA), plant height, flavonoids, anthocyanins, gas exchange, chlorophyll, leaf proline, and relative water content. Our results showed that water regimes between 309 and 389 mm can be recommended for quinoa in the Cerrado region. CPAC6 and CPAC13 presented the highest yield and PUAA under high and intermediate WRs, and hence were the most suitable for winter growth under irrigation. CPAC17 is most suitable for off-season growth under rainfed conditions, as it presented the highest PUAA under the low WRs (247 and 150). CPAC9 stood out in terms of accumulation of flavonoids and anthocyanins in all WRs. Physiological analyses revealed different responses of the genotypes to water restriction, together with symptoms of stress under lower water regimes. Our study reinforces the importance of detailed analyses of the relationship between productivity, physiology, and water use when choosing genotypes for planting and harvest in different seasons.

Morphophysiology of Jatropha curcas L. plants under different water regimes

The effect of different water regimes on Jatropha curcas seedling growth was investigated. The study was carried out in a greenhouse covered with transparent plastic. Seeds were sown in five-liter recipients containing substrate consisting of 3:1:0.5 soil, sand and manure, respectively. A completely randomized plot design was used with seven treatments and five replications. The plants were irrigated with 100% substrate retention capacity until 30 days of age when they were submitted to water volumes of 25%, 50%, 75%, 100%, 125%, 150% and 175% substrate retention capacity for 30 days. The short duration of the research explains the slight decreases in the RMR and TRA but they were sufficient to support the assertion that excess water may have inhibited aquaporin activity and partially reduced soil solution absorption and TRA. Thus, both water deficit and excess water inhibited the growth of J. curcas plants, however, the water deficit inhibited more strongly the development of the species at the initial stages of the restriction, while excess water only caused damage after a longer period of exposure. The assessments were made when the plants were 60 days old. The J. curcas plants showed an isohydric mechanism of stomatal control and maintained turgidity under water shortage, and, under excess water, the alterations in the root system and relative water content preceded reduction in stomatal conductance. The initial growth of J. curcas plants was shown to be sensitive to water shortage and but not very vulnerable to water excess

Role of climate change variables (standing water and rainfall) on dissipation of chlorantraniliprole from a simulated rice ecosystem

Chlorantraniliprole (CAP) is extensively used for rice pest management. Lack of information on the role of standing water and amount and timing of rainfall on CAP dissipation in rice ecosystem could hamper its prospective use. Present study was performed to investigate the effects of different water regimes (saturated, 5 and 10 cm standing water) and simulated rainfall (40 and 100 mm occurred at 4, 8 and 24 h after CAP application) on leaching, surface runoff and dissipation of CAP into components of rice ecosystem. The results showed highest concentration of CAP residues in soil and plant under saturated condition followed by 5 and 10 cm standing water conditions. Whereas, the highest concentration of CAP in leachates was detected under 10 cm standing water (12.19 ng mL−1). The results revealed large amount of leaching (21.99 ng mL−1) and surface runoff (42.25 ng mL−1) losses of CAP when 100 mm rainfall occurred at 4 h after pesticide application. The total quantity of CAP residues in soil and plant was highest when rainfall occurred at 24 h after pesticide application under both the rainfall amounts. Water stagnation and high intensity rainfall occurred shortly after pesticide application will contribute to pesticide loss to non-target sites through surface run-off and leaching. There will be less pesticide available in soil for plant uptake which may not be sufficient to kill the target organisms.

PRODUCTION PERFORMANCE OF BRS TUMUCUMAQUE COWPEA UNDER DIFFERENT PLANT DENSITIES AND WATER REGIMES1

ABSTRACT Cowpea is a legume of great socioeconomic importance for the North and Northeast regions of Brazil. However, studies to evaluate its production performance when cultivated under irrigated regime and under different plant densities are necessary. The objective of this work was to evaluate the effects of different water regimes and different plant densities on grain yield, production components and water use efficiency, and on the correlation between grain yield and production components of BRS Tumucumaque cowpea cultivar. The experiment was carried out at Embrapa Meio-Norte experimental area, in Teresina, Piauí State, Brazil, from June to September 2017, in an Argissolo Vermelho-Amarelo eutrófico (Ultisol). A randomized complete block design was used, in a split-plot scheme with four replicates, in which the water regimes occupied the plots (187.7; 233.5; 263.5 and 288.7 mm) and plant densities, the subplots (12; 16; 20 and 24 plants m-2). The number of pods per plant, number of pods per square meter, pod length, dry grain yield and water use efficiency were evaluated. The maximum dry grain yield reached was 1,694.46 kg ha-1, with application of 288.7 mm and density of 20.4 plants m-2. The production component number of pods per square meter was the most correlated with dry grain yield.

Effect of water-saving irrigation on the N2O dynamics and the contribution of exogenous and endogenous nitrogen to N2O production in paddy soil using 15N tracing

Water-saving irrigation techniques can effectively mitigate methane emissions from rice fields but typically enhance nitrous oxide (N2O) emissions due to changes in soil moisture content. However, few studies have examined the effect of different water regimes on N2O production using different species of exogenous nitrogen (N) fertilizer application. Furthermore, the contributions of exogenous N fertilizer and endogenous N of soil for N2O productions have not been elucidated. Using a series of lysimeters, three types of water management were employed in rice cultivation in this study: conventional irrigation management (CIM), alternate wetting and drying (AWD), and dry cultivation management (DCM). Ammonium nitrate (NH4NO3) fertilizer was applied as base, tillering, and heading fertilizer, which was then separated into two groups labeled with 15N stable isotope (> 99 %) at two different N positions: 15NH4NO3 and NH415NO3.Higher peaks of N2O flux were observed following drainage of floodwater for AWD and DCM treatments. In addition, 15N2O fluxes were clearly separated into two different patterns between 15NO3– and 15NH4+ fertilizer application. Application of 15NO3− fertilizer rapidly released 15N2O but the 15N2O flux for 15NH4+ fertilizer application slowly increased with a hysteresis effect, suggesting denitrification was the main pathway for 15N2O production in paddy soil with 15NO3− fertilizer added in a flooded situation. Conversely, 15NH4+ may need to be converted into 15NO3– through nitrification, then denitrified and finally released as 15N2O. Furthermore, N2O production was likely enhanced by nitrification–denitrification processes due to the water level alternating near the ground surface for AWD treatment. Consequently, the total N2O emission over the rice growing period was the highest from the AWD soils, at 2.4 times that for CIM treatments. The high proportion of N2O-N derived from soil endogenous N sources (81 % of total N2O emission) in the AWD treatment indicates that the alternating wetting–drying of soil stimulated N2O production using endogenous N mineralized from soil organic matter. Furthermore, water management of paddy soil affected N uptake by rice plants. The total N uptake by rice plants was significantly higher for CIM than for AWD and DCM treatments.

Effects of Different Water Regimes and Spacing on Insect Pest Infestation and Efficacy of Control Measures in Cucumber (Cucumis sativus)

Aim: Information on the influence of water availability during different seasons of rainfed or irrigated agriculture as it relates to insect pest population build-up in crops could assist in the development of integrated pest management. A study was therefore conducted to investigate effects of spacing, pest infestation and control on cucumber under rainfed and irrigated conditions.
 Place and Duration of Study: At the Teaching and Research Farm, Ekiti State University, Ado Ekiti, Nigeria during the 2016/2017 rainy and dry seasons.
 Methodology: The experiment was laid out using randomized complete block design (RCBD) in a split-plot arrangement in five replications, with spacing (60 x 60 cm, 60 x 90 cm and 60 x 120 cm) as the main plot treatments and the sub-plot treatments were different pest control strategies. The pest control strategies include synthetic insecticide (Lambda-cyhalothrin), botanical insecticide (Anogeissus leiocarpus) and control. Growth parameters and yield attributes were recorded. Insect pest occurrence, their build-up and percentage infestation on cucumber and the efficacy of the management strategies were monitored.
 Results: The results showed that yield was enhanced in irrigated system with the widest spacing of 60 x 120 cm botanical treatment interaction. Bemisia tabaci was the most prominent insect pest attacking cucumber under irrigated system.
 Conclusion: Other cultural control practices such as the use of trap crops with little or no financial implication should also be added to botanical pesticides as an integrated pest management tactic for effective management and control of the pest.

Comparative transcriptome analysis of translucent flesh disorder in mangosteen (Garcinia mangostana L.) fruits in response to different water regimes.

Translucent flash disorder (TFD) is one of the important physiological disorders in mangosteen (Garcinia mangostana L.). TFD has symptoms such as flesh arils that become firm and appear transparent similar to watercore in apple or pear. Information on the changes of gene expression in TFD-affected tissues remain limited, and investigations into the effects of different water regimes still need to be undertaken. Through an RNA sequencing approach using the Ion Proton, 183,274 contigs with length ranging from 173–13,035 bp were constructed by de novo assembly. Functional annotation was analyzed using various public databases such as non-redundant protein NCBI, SwissProt, and Gene Ontology, and KEGG pathway. Our studies compared different water regimes to incidence and differentially expressed genes of TFD-like physiological disorders. From the differentially expressed gene (DEG) between normal air and TFD-affected aril, we identified DEG-related TFD events, which 6228 DEGs in the control condition and 3327 DEGs in under water stress treatment condition remained, and confirmed these with RT-qPCR, including sucrose synthase (SUSY), endoglucanase (GUN), xyloglucan endotransglucosylase/hydrolase (XTH), and polygalacturonase (PG) showed statistically significant. In addition, transcription factors also indicated changes in MYB, NAC and WRKY between tissues and different water regimes.

Effects of Water Regimes on Methane Emissions in Peatland and Gley Marsh

Core Ideas Large pulses of CH4 can be emitted during short‐duration drying–wetting episodes. Peatland soils had higher CH4 emissions than gley marsh soils under a steady water table. Accurate CH4 estimates should include weather events that cause rapid changes in soil moisture regimes. The increasing frequency of extreme drought and intense precipitation events with global warming may affect CH4 emissions from different types of wetlands by regulating drying–wetting cycles. To determine the effects of different water regimes on CH4 emissions, a mesocosm experiment was conducted. Soil cores sampled from peatland and gley marsh were subjected to two drying–wetting cycles (i.e., fluctuating between −10 and 10 cm for 7 and 15 d, respectively) and three steady water table treatments (10, 0, and −10 cm). Alternation between drying and wetting stimulated CH4 emissions (F = 16.03 for 7 d and F = 31.85 for 15 d, P < 0.01). The highest emission pulses were observed between 4 and 9 d after the water table increased according to the models. Peak pulse emissions significantly increased by 41% in peatland and 109% in gley marsh after rewetting compared with that in the steady 0‐cm water table treatment. Peatland soils had higher CH4 emissions than gley marsh soils under steady water table treatments (P < 0.01). This study shows that large pulses of CH4 can be emitted during short‐duration drying–wetting episodes. If these pulses are not accounted for in budgets, CH4 emissions may be incorrectly assessed when comparing with field measurements during regularly spaced sampling intervals over only a few days or weeks by the static opaque chamber technique. Accurate estimates of CH4 budgets not only depend on increased measurement frequency but by necessity should incorporate weather events that cause rapid changes in the soil moisture regime.

Effects of different water regimes and nitrogen application strategies on grain filling characteristics and grain yield in hybrid rice

ABSTRACTIn order to optimize N application and understand how the different combinations of water and N management affect grain filling characteristics and yield, we designed three irrigation regimes (W1 submerged irrigation, W2 alternate irrigation, W3 dry cultivation), and different N application strategies at 180 kg ha−1 in 2010 and 2011. The relationship between grain filling characteristics and grain yield formation were respectively investigated. The results revealed that there were obvious interacting effects of irrigation regime and N application strategies on grain yield and grain-filling characteristics as well. Compared with W1 and W3 treatments, under W2, the N-fertilizer should account for 30% base, 30% tillering, and 40% panicle fertilizer with the last being applied equally at 4th and 2nd leaves emerged from the top. Correlation analysis revealed that grain filling rate during middle grain-filling stage was the largest and contribute more than 50% to grain-filling. Grain yield was significantly related to grain filling rate (Gmax or Gmean), final weight of a kernel (A), and mean grain filling rate (MGR) of the early, mid and late stages during grain filling in inferior spikelets, which is the important reason for water and N coupling effect further to increase yield and fertilizer use efficiency.

Influence of water stresses on capsaicinoid production in hot pepper (Capsicum chinense Jacq.) cultivars with different pungency levels

Although water stress reduces fruit yield, it also increases capsaicinoid accumulation in hot pepper. The aim of this study was to investigate the effect of different water regimes on capsaicinoid production in Capsicum chinense Jacq. having different pungency levels. Four hot pepper (C. chinense) cultivars were planted with four water regimes after anthesis: daily irrigation (control; S1), every 2 days (S2), every 3 days (S3) and every 4 days (S4). The results found that Akanee Pirote with the S2 treatment gave the highest capsaicinoid yield, and the increase of capsaicinoid yield was attributed from increasing the absolute capsaicinoid content and reducing the dry fruit yield as compared to the control. Capsaicinoid yield of Bhut Jolokia, Orange Habanero, and BGH1719 responded to the water stresses, but produced less capsaicinoid yield as compared to the control. This study reveals that appropriate water stress could increase capsaicinoid yield in some, but not all, hot pepper cultivars.

Effect of water regimes and plant densities on cowpea production1

ABSTRACT Cowpea has been cultivated in a rudimentary form in the main producing regions of Brazil, resulting in lower grain yields, when compared to the crop potential. The use of technologies such as water regimes, adequate plant density and soil management are alternatives to increase this crop yield. This study aimed at evaluating the effects of different water regimes and plant densities on the yield components of cowpea cultivated under conventional and no-tillage systems. A randomized block design in a split-plot factorial, with four replications, was used. The treatments consisted of five water regimes in the plots (157.00 mm, 189.00 mm, 234.00 mm, 274.00 mm and 320.00 mm) and five plant densities as subplots (12 plants m-2, 16 plants m-2, 20 plants m-2, 24 plants m-2 and 28 plants m-2). The evaluated variables were: number of pods per plant, number of pods per area, pod length and grain yield. The combination between 270 mm of irrigation water depth with a density of 280,000 plants ha-1 resulted in higher grain yield using the no-tillage system, while the combination between the density of 280,000 plants ha-1 and 320 mm of water depth favored the highest grain yields in the conventional growing system.

Water Use Efficiency, Yield and Crop Coefficient (Kc) of Groundnut crop under different Water Regimes

The pot experiment was carried out during September 2015 to January 2016 at instructional farm, College of Agricultural Engineering, UAS Raichur under rain shelter to study the effect of different water regimes, (i.e. T1:100, T2:90, T3:80, T4:70, T5:60 and T6:50) per cent of water application with available moisture holding capacity on grain yield and water use efficiency. Completely Randomized block design with four replications was used in this study. The results showed that there was significant difference between the yield and (WUE) under different levels of irrigation. The total irrigation water applied were (i.e., 211.98, 243.02, 225.78, 155.09, 135.51 and 105.62 mm/plant) under different water regime treatments (100, 90, 80, 70, 60 and 50 %) of available moisture holding capacity (AMHC) respectively. Grain yield productions under different treatments were 106.25, 171.25, 127.50, 75, 55 and 40.75 g/plant/pot at 100, 90, 80, 70, 60 and 50 per cent of AMHC respectively. The results showed that water use efficiency (WUE) at different treatments were 0.50, 0.70, 0.56, 0.48, 0.41 and 0.39 g/mm for (100, 90, 80, 70, 60 and 50 %) per cent of AMHC respectively. Therefore, the 90 % of AMHC treatment (T2) is recommended for groundnut irrigation for water saving. The comparison of actual crop coefficient that obtained by water balance technic in experiment and crop coefficient (Kc) values of groundnut for different crop growth stages were selected based on the values suggested by FAO (Allen et al., 1998) are similar in the treatment of 90 % (T2) of the AMHC. Furthermore, the result showed that the treatment of 90 per cent of Available moisture holding capacity (T2) seemed to be better adapted to product a high crop yield with acceptable yield coupling with water use efficiency in this region.

Perusing biochemical antioxidant enzymes as selection criteria under drought stress in wheat varieties

ABSTRACTIn regard to important roles of enzymatic antioxidant in abiotic stresses, and their practical use as stress indices, the current research was implemented to peruse antioxidant enzymatic activities of different wheat varieties and to find the susceptible and the tolerant varieties based on these indices. The experiment was carried out in the greenhouse of Islamic Azad University, Sanandaj, Iran in 2015. A factorial experiment based on completely randomized design (CRD) with three replications were used to evaluate the effects of different water regimes, including 100% and 50% field capacity (FC) on 25 wheat cultivars. Antioxidant enzyme activities, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbic peroxidase (APX), and grain yield of the wheat varieties were measured. The results showed that under normal irrigation condition, the relationships between grain yield and antioxidant were inversed, but under stressful condition the relationships between wheat grain yield and some important antioxidants such as CAT and SOD were positive. Among antioxidant enzymes, SOD activity showed a higher variation among wheat varieties of this study, indicating that this enzyme is an important trait to be used in the breeding programs. Based on the results of different statistical techniques and comparing relationships among traits for normal irrigation and stress condition, enzymatic antioxidant could be used as practical criteria for screening tolerant genotypes of wheat. On the other side, SOD and CAT resulted in being the most important criteria for achieving higher tolerant genotypes through indirect selection.

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Effects of Fertilization Rate and Water Availability on Peanut Growth and Yield in Senegal (West Africa)

<p>The effects of fertilization rate and water availability on peanut growth and yield of two cultivars were investigated in a series of field experiments at Bambey, Nioro and Sinthiou Malem in Senegal. Both rainy and dry season experiments were conducted over two years between 2014 and 2015, for a total of seven experiments. The first set of four experiments were to evaluate fertilizer application rate on peanut production. One experiment was conducted in the dry season 2014 in Nioro with four levels of fertilizer and one experiment in the rainy season 2014 in each of Bambey, Nioro and Sinthiou Malem with six levels of fertilizer in a RCBD with four replications both. The second set of experiments were to evaluate the effect of different water regimes on peanut production. Experiments were conducted in the dry season of 2014 and 2015 in Bambey and in Nioro 2015. The experimental design was a split plot design with four replications and three levels of water, namely, E, S1 and S2. The effects of fertilization rate on peanut in three different sites were not significantly different between fertilizer levels. However, irrigation treatments were significantly different in all sites during the two years. Under water stressed conditions, the seed yield was more affected than the biomass yield. Seed yield decreased by 33% when stress occurred at flowering period and by 50% when stress occurred during seed filling. The most sensitive period for yield declined was observed during the period of maturation followed to the flowering stage. The interaction between irrigation and fertilizer was not signification in both Bambey and Nioro sites of field experiments. Such experiments should be conducted in field based conditions where occur limited soil nutrients to test higher dose of NPK.</p>