Water Deficit Research Articles

Innovative multi-trial breeding and genotype screening in triticale (x Triticosecale Wittmack) for enhanced stability under drought stress.

Triticale is a man-made crop produced by crossing wheat (Triticum aestivum) and rye (Secal cereal) with the aim of increasing the adaptability and potential production of its parental line (wheat) under environmental stresses and harsh conditions. Accordingly, the objectives of this study are as follow, a: compare different stability measurement methods regarding their suitability, b: identify most stable genotypes for cultivar release, and c: provide a freely available package in R programming language (named 'Stbidx') capable of exploiting all stability methods for similar studies. Accordingly, 30 triticale genotypes were evaluated for their stability and adaptability to changing environments during four consecutive years from 2016 to 2020 in different locations in Iran (one year in Zarghan, two years in Ghorveh, one year in Sanandaj) and under two different irrigation regimes (normal irrigation and water deficit stress conditions). All 30 triticale genotypes were cultivated in a randomized complete block design (RCBD) with three replications in each environment (12 environments: 6 trials in 2 conditions). Grain yield of triticale genotypes was measured and it applied to calculate all known stability indices (univariate methods) along with the meta-analysis models were evaluated in this study. Additionally, two novel techniques (Stability ID: SID and AMMI PC Value: APCV) were introduced and successfully tested for screening stable genotypes. These methods were introduced to improve and resolve the limitation of the previous stability methods. Meanwhile, heatmap analysis, as a proper data-mining technique, has been successfully applied for the first time to find stable genotypes in different environments in this study. The results clearly indicated a higher suitability of our introduced methods over previous multi-trials screening methods. Based on our methods and considering all environments, triticale genotypes ELTTCL21 (SID = 8.00; APCV = 28.12), ELTTCL25‌ (SID = 8.14; APCV = 30.02), ELTTCL30 (SID = 8.43; APCV = 17.00), ET-90-8 (SID = 14.00; APCV = 42.05), and Sanabad (SID = 10.57; APCV = 12.44) were among stable genotypes and they can be nominated as new cultivars. Additionally, for stress condition genotypes ELTTCL30 (stress: 380.6g/m2) and ELTTCL18 (stress: 360.79g/m2) and for normal condition genotypes ET-90-4 (normal: 849.4g/m2) and ELTTCL20 (normal:845g/m2) were respectively the most proper genotypes with the highest production to be considered for each condition separately.

Nitrate reductase activity in ‘Syrah’ grapevine under three irrigation strategies

The objective of this study was to evaluate the activity of the enzyme nitrate reductase in ‘Syrah’ grapevine under three irrigation strategies. Irrigation was applied by a drip system, and the treatments were started 45 days after production pruning. The statistical design was completely randomized in a 3 x 5 factorial, corresponding to three irrigation strategies: controlled deficit irrigation, deficit irrigation and full irrigation, and five collections along the cycle: at 54, 60, 73, 87 and 101 days after pruning. Deficit irrigation and controlled deficit irrigation treatments caused longer water deficit to plants and reduced nitrate reductase activity. Full irrigation treatment promoted the highest values of leaf water potential and nitrate reductase activity at the end of the cycle. Leaf water potential and leaf age influence nitrate reductase activity.

Modulatory responses of physiological and biochemical status are related to drought tolerance levels in peanut cultivars.

Peanut (Arachis hypogaea L.) is the fourth most cultivated oilseed in the world, but its cultivation is subject to fluctuations in water demand. Current studies of tolerance between cultivars and physiological mechanisms involved in plant recovery after drought are insufficient for selection of tolerant cultivars. We evaluated tolerance of different peanut cultivars to water deficit and subsequent rehydration, based on physiological and biochemical status. Gas exchange, photosynthetic pigments, Fv/Fm, MDA, H2O2 and antioxidant enzyme activity were analysed. Drought stress and rehydration triggered distinct changes in pigments, Fv/Fm, gas exchange, and H2O2 across genotypes, with increased MDA in all cultivars under stress. Based on multivariate analysis, 'IAC Sempre Verde' was identified as most drought sensitive, while 'IAC OL3', 'IAC 503', and 'IAC OL6' exhibited variations in physiological responses and antioxidant activity correlated to their respective tolerance levels. Notably, 'IAC OL3' had higher WUE and enhanced enzymatic defence and was classified as the most drought tolerant in this context. The above findings suggest that antioxidant metabolism is a important factor for plant recovery post-rehydration. Our study provides insights into antioxidant and physiological responses of peanut cultivars, which can support breeding programs for selection of drought-tolerant genotypes. Future field studies should be conducted for a better understanding of tolerance of these cultivars, particularly through correlation of these data with crop yield impact.

Pilot Evaluation of Field Pea Accessions Under Water Deficit Conditions

Field pea, a key pulse crop for sustainable agriculture, faces significant production challenges due to drought, exacerbated by extreme climatic changes. This study evaluated 17 field pea plant introductions (PIs) and two commercial varieties under greenhouse conditions to assess their performance, determine the relationships between agronomic traits and grain yield (GY), and identify genotypes with stable yields under drought stress. Two water treatments were applied: 100% field capacity for well-watered (WW) and 60% field capacity for water deficit (WD) conditions, with drought stress imposed 21 days after planting. Significant genotypic variation was observed under both conditions. Water deficit significantly reduced GY, the number of pods per plant (NPP), plant height (PH), aboveground dry vegetative biomass (ADVB), and days to maturity (DTM) while increasing stomatal density on both adaxial (SD.ADX) and abaxial leaf surfaces (SD.ABX). Traits associated with GY in WW, such as NPP, PH, ADVB, and SD.ADX, showed stronger correlations under WD, with DTM being significantly associated with GY only in WD. Top-performing genotypes in both conditions exhibited higher pod numbers, increased aboveground dry vegetative biomass, late maturity, and lower adaxial stomatal density. Notably, PI 272215 was identified as a top performer under both conditions, with an 88% yield stability index. PI 180702 demonstrated comparable performance to PI 272215 but with no yield loss under the same conditions. These findings can be used for future field pea breeding programs aimed at developing drought-tolerant field pea varieties.

Mycorrhization and chemical seed priming boost tomato stress tolerance by shifts of primary and defence metabolic pathways.

Priming modulates plant stress responses before the stress appears, increasing the ability of the primed plant to endure adverse conditions and thrive. In this context, we investigated the effect of biological (i.e., arbuscular mycorrhizal fungi, AMF) agents and natural compounds (i.e., salicylic acid applied alone or combined with chitosan) against water deficit and salinity on a commercial tomato genotype (cv. Moneymaker). Effects of seed treatments on AMF colonization were evaluated, demonstrating the possibility of using them in combination. Responses to water and salt stresses were analysed on primed plants alone or in combination with the AMF inoculum in soil. Trials were conducted on potted plants by subjecting them to water deficit or salt stress. The effectiveness of chemical seed treatments, both alone and in combination with post-germination AM fungal inoculation, was investigated using a multidisciplinary approach that included eco-physiology, biochemistry, transcriptomics, and untargeted metabolomics. Results showed that chemical seed treatment and AM symbiosis modified the tomato response to water deficit and salinity triggering a remodelling of both transcriptome and metabolome, which ultimately elicited the plant antioxidant and osmoprotective machinery. The plant physiological adaptation to both stress conditions improved, confirming the success of the adopted approaches in enhancing stress tolerance.

Effects of Melatonin Pre- and Post-Drought Treatment on Oxidative Stress Markers and Expression of Proline-Related Transcripts in Young Wheat Plants

Wheat can tolerate a mild water deficit, but prolonged drought causes a number of detrimental physiological changes resulting in a substantial decrease in productivity. The present study evaluates the potential of the natural plant growth regulator melatonin to alleviate the negative effects of moderate drought in two Bulgarian winter wheat cultivars at the early vegetative stage. Melatonin doses of 75 µM were root-supplemented 24 h before or after the stress period. The levels of several biometric parameters, osmolyte content and stress indicators as well as the expression of genes coding for key enzymes of the proline biosynthesis pathway were analyzed in leaves at the end of the drought stress and after two and four days of recovery. Applied alone, melatonin did not exert significant effects on most of the monitored parameters. Water deprivation negatively affected seedlings’ fresh weight and water content and increased the stress markers and osmolyte levels. These were accompanied by a high accumulation of TaP5CS and TaP5CR transcripts coding for the enzymes Δ-pyrroline-5-carboxylate synthase and Δ-pyrroline-5-carboxylate reductase, respectively. The effect of melatonin in reducing drought stress was similar whether applied before or after exposure, though slightly more effective when used as a pre-treatment.

Evidence for the acclimation of ecosystem photosynthesis to soil moisture.

Ecosystem gross primary productivity (GPP) is the largest carbon flux between the atmosphere and biosphere and is strongly influenced by soil moisture. However, the response and acclimation of GPP to soil moisture remain poorly understood, leading to large uncertainties in characterizing the impact of soil moisture on GPP in Earth system models. Here we analyze the GPP-soil moisture response curves at 143 sites from the global FLUXNET. We find that GPP at 108 sites exhibits hump-shaped response curves with increasing soil moisture, and an apparent optimum soil moisture ( , at which GPP reaches the maximum) exists widely with large variability among sites and biomes around the globe. Variation in is mostly explained by local water availability, with drier ecosystems having lower than wetter ecosystems, reflecting the water acclimation of . This acclimation is further supported by a field experiment that only manipulates water and keeps other factors constant, which shows a downward shift in after long-term water deficit, and thus a lower soil water requirement to maximize GPP. These results provide compelling evidence for the widespread and its acclimation, shedding new light on understanding and predicting carbon-climate feedbacks.

Understory Environmental Conditions Drive Leaf Level-Lipid Biosynthesis in a Deciduous and Evergreen Tree Species.

Plants in the understory experience climatic conditions affected by the overstory canopy that influence physiological and biochemical processes. Here, we investigate the relationships of leaf lipid molecular abundances to leaf water content, transmitted irradiance, and free-air temperature (Tair) from deciduous angiosperm (Quercus buckleyi) and evergreen gymnosperm (Juniperus ashei) understory trees across an elevation gradient in a central Texas (USA) woodland. Monthly sampling from 04/2019 to 01/2020 revealed that long-chain leaf waxes (≥ C27) accumulated with leaf water deficit over the growing season for both tree species. Higher transmitted light during the hottest, driest months was due to a decreased leaf area index (LAI) in the canopy as leaf shedding is a common drought response. Isoprenoids (sesqui-, di-terpenoids, phytosterols) in leaves changed by month with changing LAI and transmittance associated with monthly Tair changes. The chain length of n-alkanols in Q. buckleyi shifted with seasonal LAI at different topographic positions. The unsaturation of fatty acids in both tree species decreased with increased seasonal Tair but showed topography sensitivity. Leaf-level metabolites responded to understory microclimatic variables that were influenced by seasonality and topography.

The Problem of Drought in the Territory of Azerbaijan and Combat Measures

The article considers global and local climate change, and the problems associated with these changes. The increase in drought in the world and in Azerbaijan. The influence of various types of anthropogenic impact on the environment is studied. Measures to reduce their negative consequences are proposed. 52.4% of the total land fund of Azerbaijan is suitable for agriculture. The bulk of the soil is in arid areas (Kura-Araz lowland, including the Salyan, Mil, Mugan, Shirvan and Karabakh plains). Drought is also observed in the foothills of the Lesser Caucasus. Growing crops without irrigation is impossible. Problems arise in irrigating crop areas in dry years. The presence of drought in the summer months and a decrease in water resources negatively affect agriculture. The total water deficit in Azerbaijan in 2020 amounted to more than 0.2 km3. The water deficit may increase to 1.3 km3 in 2030 but may amount to 4-5 km3 in 2050. It is proposed to use current technologies in the country's natural resource management system.

Studying the Combined Impact of Salinity and Drought Stress-Simulated Conditions on Physio-Biochemical Characteristics of Lettuce Plant

Water scarcity and increasing salinity stress are significant challenges in the farming sector as they often exacerbate each other, as limited water availability can concentrate salts in the soil, further hindering plant growth. Lettuce, a crucial leafy vegetable with high nutritional value, is susceptible to water availability and quality. This study investigates the growth and development of lettuce plants under water scarcity and varying levels of salinity stress to identify effective strategies for reducing water consumption while maintaining or improving plant productivity. Field experiments were designed to simulate three drought levels (50, 75, and 100% of class A pan evaporation) and three salinity stress levels (control, 1500, and 3000 ppm NaCl), assessing their impact on lettuce’s morphological and biochemical parameters. The combination of reduced water supply and high salinity significantly hindered growth, underscoring the detrimental effects of simultaneous water deficit and salinity stress on plant development. Non-stressed treatment enhanced nitrogen, phosphorus, and potassium contents and progressively decreased with the reduction in water supply from 100% to 50%. Interestingly, higher salinity levels increased total phenolic, flavonoid, and antioxidant activity, suggesting an adaptive stress response. Moreover, antioxidant activity, evaluated through DPPH and ABTS assays, peaked in plants irrigated with 75% ETo, whether under control or 1500 ppm salinity conditions. The Yield Stability Index was highest at 75% ETo (0.95), indicating robust stability under stress. The results indicated that lettuce could be cultivated with up to 75% of the water requirement without significantly impacting plant development or quality. Furthermore, the investigation demonstrated that lettuce could thrive when irrigated with water of moderate salinity (1500 ppm). These findings highlight the potential for reducing water quantities and saline water in lettuce production, offering practical solutions for sustainable farming in water-scarce regions.

A multi-trait targeted genotype selection approach for screening drought tolerance in teosinte–maize hybrids

Drought tolerance is a complex characteristic and screening based on multiple traits rather than direct selection indices would result in more efficient selection. The study aims to select hybrids under optimal and water deficit conditions to achieve genetic gains in yield traits without compromising the other secondary traits viz., anthesis-silking interval, leaf chlorophyll content, delayed leaf rolling and leaf senescence, relative water content, and ROS scavenging using the multi-trait genotype ideotype distance index. The 30 teosinte-maize hybrids along with four checks were evaluated for two classes of traits: 16 morphometric and 14 physiological and biochemical traits, under well-watered (WW) and water-stress (WS) environments. Significant variations among the genotypes were observed for most traits and the presence of moderate to high heritability for most traits suggests direct selection for improvement of those traits. Significant correlation of the traits with yield and intercorrelations between traits indicate the advantage of indirect selection based on secondary traits. By assuming a selection intensity of 15% and equal weightage to all the traits, five genotypes were selected based on the MGIDI under each class of traits and in each environment. The genotypes viz. G19, G20, and G29 were commonly selected across both environments. The selection led to desired positive and negative selection gains for most of the traits studied and resulted in high positive gains for single plant yield of 35.6% under WW and 69.3% under WS. The strength and weakness plots effectively present the advantages and limitations of the selected genotypes under each environment. The multi-trait-based selection approach is an effective tool for selecting genotypes and designing breeding strategies for stress breeding.

Early Modeling of the Upcoming Landsat Next Constellation for Soybean Yield Prediction Under Varying Levels of Water Availability

The upcoming Landsat Next will provide more frequent land surface observations at higher spatial and spectral resolutions that will greatly benefit the agricultural sector. Early modeling of the upcoming Landsat Next products for soybean yield prediction is essential for long-term satellite monitoring strategies. In this context, this article evaluates the contribution of Landsat Next’s improved spectral resolution for soybean yield prediction under varying levels of water availability. Ground-based hyperspectral data collected over five cropping seasons at the Brazilian Agricultural Research Corporation were resampled to Landsat Next spectral resolution. The spectral dataset (n = 384) was divided into calibration and external validation datasets and investigated using three strategies for soybean yield prediction: (1) using the reflectance from each spectral band; (2) using existing and new vegetation indices developed based on three general equations: Normalized Difference Vegetation Index (NDVI-like), Band Ratio Vegetation Index (RVI-like), and Band Difference Vegetation Index (DVI-like), replacing the traditional spectral bands by all possible combinations between two bands for index calculation; and (3) using a partial least squares regression (PLSR) model composed of all Landsat Next spectral bands, in comparison to PLSR models using Landsat OLI and Sentienel-2 MSI bands. The results show the distribution of the new spectral bands over the most prominent changes in leaf reflectance due to water deficit, particularly in the visible and shortwave infrared spectrum. (1) Band 18 (centered at 1610 nm) had the highest correlation with yield (R2 = 0.34). (2) A new vegetation index, called Normalized Difference Shortwave Vegetation Index (NDSWVI), is proposed and calculated from bands 19 and 20 (centered at 2028 and 2108 nm). NDSWVI showed the best performance (R2 = 0.37) compared to traditional existing and new vegetation indices. (3) The PLSR model gave the best results (R2 = 0.65), outperforming the Landsat OLI and Sentinel-2 MSI sensors. The improved spectral resolution of Landsat Next is expected to contribute to improved crop monitoring, especially for soybean crops in Brazil, increasing the sustainability of the production systems and strengthening food security in Brazil and globally.

Interplays of Cuticle Biosynthesis and Stomatal Development: From Epidermal Adaptation to Crop Improvement.

Crop production is limited by environmental stresses such as a water deficit, salinity, and extreme temperature. Lipophilic cuticle and stomatal pore govern plant transpirational water loss and photosynthetic gas exchange and contribute to plant adaptation to stressful environments. Intricate interplays between cuticle biosynthesis and stomatal development are supported by increasing evidence from phenotypic observations. Several mutants, initially identified as being deficient in cuticle development, have exhibited altered phenotypes in terms of stomatal ridges, numbers, patterns, and shapes. Similarly, mutants with abnormal stomatal patterning have shown defective cuticle formation. Recently, signaling components and transcription factors orchestrating cuticle biosynthesis and stomatal formation have been characterized in both model and crop plants. In this review, we summarize the genetic interplay between cuticle biosynthesis and stomata formation. Current strategies and future perspectives on exploiting the intertwined cuticle biosynthesis and stomatal development for crop stress resistance improvement are discussed.

Should we delay leaf water potential measurements after excision? Dehydration or equilibration?

BackgroundAccurate leaf water potential (Ψw) determination is crucial in studying plant responses to water deficit. After excision, water potential decreases, even under low evaporative demand conditions, which has been recently attributed to the equilibration of pre-excision Ψw gradients across the leaf. We assessed the influence of potential re-equilibration on water potential determination by monitoring leaf Ψw and relative water content decline after excision using different storage methods.ResultsEven though leaf Ψw declined during storage under low evaporative demand conditions, this was strongly reduced when covering the leaf with a hydrophobic layer (vaseline) and explained by changes in relative water content. However, residual water loss was variable between species, possibly related to morpho-physiological leaf traits. Provided water loss was minimized during storage, pre-excision leaf transpiration rate did not affect to the magnitude of leaf Ψw decline after excision, confirming that transpiration-driven Ψw gradients have no effect on leaf Ψw determination.ConclusionsDisequilibrium in water potentials across a transpiring leaf upon excision is dissipated very quickly, well within the elapsed time between excision and pressurization, therefore, not resulting in overestimation of leaf Ψw measured immediately after excision. When leaf storage is required, the effectiveness of a storage under low evaporative demand varied among species. Covering with a hydrophobic layer is an acceptable alternative.

Seed priming - induced drought tolerance in Castor: Unravelling the physiological and molecular mechanisms

Castor is an essential nonedible oilseed crop with significant applications in the cosmetic and chemical industries. It is cultivated primarily in rainfed regions, where drought is a common abiotic stress factor. Seed germination, the critical initial stage, is particularly affected by drought. Seed priming with radical scavenging chemicals such as salicylic acid, melatonin, hydrogen peroxide and ascorbic acid has been explored to increase germination under water deficit conditions. This study aimed to evaluate the effects of different concentrations of these chemicals on the physiological and antioxidant enzyme activities of castor under drought stress. Two water regimes were applied in the study. Among the treatments, seed priming with 80 ppm salicylic acid significantly improved key parameters, including the germination % (71 %), speed of germination (4.1 %), vigour index (3141), chlorophyll content (28.3 SPAD units) and relative water content (63 %). It also increased the antioxidant enzyme activities such as CAT, POD, SOD and APX, along with the overexpression of the drought-responsive gene RCECP63 under water deficit conditions. These findings highlight that seed priming, particularly with salicylic acid, offers a promising strategy to enhance castor resilience under prolonged drought stress, providing a practical approach for improving crop performance in drought-prone regions.

Capturing drought stress signals: The potential of dendrometers for monitoring tree water status.

The severity of droughts is expected to increase with climate change, leading to more frequent tree mortality and a decline in forest ecosystem services. Consequently, there is an urgent need for monitoring networks to provide early warnings of drought impacts on forests. Dendrometers capturing stem diameter variations may offer a simple and relatively low-cost opportunity. However, the links between stem shrinkage, a direct expression of tree water deficit (TWD), and hydraulic stress are not well understood thus far. In this study, we exposed two widespread conifers Pinus sylvestris and Larix decidua to lethal dehydration by withholding water and closely monitored TWD, midday water potential ($\psi $), and midday stomatal conductance ($g_{s}$) under controlled greenhouse conditions. We found strong relationships between the three variables throughout the dehydration process, particularly suggesting the potential for continuous $\psi $ predictions and stomatal closure assessments. However, the relationships decoupled during recovery from severe drought. We also identified TWD thresholds that signal the onset of drought stress and tissue damage, providing insights into stress impacts and recovery potential. While these findings are promising, challenges remain in practically transferring them to field set-ups by suitable TWD normalization. Importantly, we observed that midday $g_{s}$ was drastically reduced when TWD persisted overnight, providing a directly applicable drought stress signal that does not require normalization. In conclusion, while challenges remain, our results highlight the potential of dendrometers for monitoring tree water dynamics. Implementing dendrometer networks could support the development of early-warning metrics for drought impacts, enabling large-scale monitoring in diverse settings, such as urban areas and forest ecosystems.

Enhancement of Tomato Fruit Quality Through Moderate Water Deficit

In arid areas, water shortage has become a major bottleneck limiting the sustainable development of agriculture, necessitating improved water use efficiency and the full development of innovative water-saving irrigation management technologies to improve quality. In the present study, tomato (Solanum lycopersicum cv. Micro Tom) fruits were used as materials, and different irrigation frequencies were set during the fruit expansion stage. The normal treatment (CK) was irrigated every three days, while the water deficit treatments were irrigated at varying frequencies: once every 4 days (T1), 5 days (T2), 6 days (T3), 7 days (T4), and 8 days (T5). These corresponded to 80%, 70%, 60%, 50%, and 40% of the maximum field moisture capacity (FMC), respectively, with CK maintaining full irrigation at 90% of the maximum FMC. The water deficit treatment T3, with less stress damage to plants and the most significant effect on fruit quality improvement, was selected based on plant growth indices, photosynthetic characteristics, chlorophyll fluorescence parameters, and fruit quality indices, and its effects on carotenoids, glycolic acid fractions, and volatile compounds during tomato fruit ripening were further investigated. The outcome indicated that moderate water deficit significantly increased the carotenoid components of the tomato fruits, and their lycopene, lutein, α-carotene, and β-carotene contents increased by 11.85%, 12.28%, 20.87%, and 63.89%, respectively, compared with the control fruits at the ripening stage. The contents of glucose and fructose increased with the development and ripening of the tomato fruits, and reached their maximum at the ripening stage. Compared to the control treatment, the moderate water deficit treatment significantly increased the glucose and fructose levels during ripening by 86.70% and 19.83%, respectively. Compared to the control conditions, water deficit conditions reduced the sucrose content in the tomato fruits by 27.14%, 18.03%, and 18.42% at the mature green, turning, and ripening stages, respectively. The moderate water deficit treatment significantly increased the contents of tartaric acid, malic acid, shikimic acid, alpha ketoglutaric acid, succinic acid, and ascorbic acid, and decreased the contents of oxalic acid and citric acid compared to the control. The contents of total soluble sugar and total organic acid and the sugar–acid ratio were significantly increased by 48.69%, 3.71%, and 43.09%, respectively, compared with the control at the ripening stage. The moderate water deficit treatment increased the fruit response values to each sensor of the electronic nose, especially W5S, which was increased by 28.40% compared to the control at the ripening stage. In conclusion, during the ripening process of tomato fruit, its nutritional quality and flavor quality contents can be significantly improved under moderate (MD) deficit irrigation treatment. The results of this experiment can lay the foundation for the research on the mechanism of water deficit aiming to promote the quality of tomato fruit, and, at the same time, provide a theoretical basis and reference for tomato water conservation and high-quality cultivation.

WATER RESOURCE BALANCE AND PROPOSED MEASURES FOR SUSTAINABLE MANAGEMENT IN THE FOUR SECTIONS OF CHAPULTEPEC FOREST

This study examined the water resources in four sections of Chapultepec Forest (CF) to assess their current state and propose strategies for proper management. The forest is significant for Mexico City due to its historical and cultural value, ecological relevance, and contribution to the quality of life of its residents. For diagnosis, a water balance was carried out under current conditions, and water supply and demand were projected to the year 2050. The results show that there is currently a water deficit in sections 1, 2, and 3, mainly due to the demand for irrigation water. Towards 2050, and considering the trend of climatological variables, an increase in the deficit is expected for the entire CF due to increased evaporation and water demand in its various uses.

Foliar Methyl Jasmonate Application Activates Antioxidant Mechanisms to Counteract Water Deficits and Aluminum Stress in Vaccinium corymbosum L.

Due to climate change, water deficits (WDs) and aluminum (Al) toxicity are increasing, affecting plants, especially crops such as blueberries (Vaccinium corymbosum L.). The application of methyl jasmonate (MeJA) could mitigate these effects. This work aimed to evaluate the effective MeJA dose to overcome oxidative stress provoked by combined WD+Al stress in blueberries. Plants of Al-sensitive (Star) and Al-resistant (Legacy) cultivars were exposed to control (Al at 65 mg/Kg, 80% field capacity), WD+Al (50% field capacity; Al at 1665 mg/Kg), and WD+Al treatment with different foliar MeJA doses (10, 50, and 100 μM) during 7 and 21 days. Data revealed that plants exposed to WD+Al and treated with 50 µM MeJA reduced Al up to 3.2-fold in roots and 2.7-fold in leaves and improved water potential (Ψw) up to 2.5-fold. The sensitive cultivar decreased the relative growth rate under WD+Al, increasing by 1.9-fold with 50 µM MeJA. Under WD+Al stress, all MeJA doses mitigated the decrease in relative water content in Al-resistant cultivars, restoring values like control plants. In the sensitive cultivar, 50 µM MeJA increased photosynthesis (1.5-fold) and stomatal conductance (1.4-fold), without changes in transpiration. Lipid peroxidation decreased (1.2-fold) and increased antioxidant activity (1.8-fold), total phenols (1.6-fold), and superoxide dismutase activity (3.3-fold) under WD+Al and 50 µM-MeJA. It was concluded that the most effective dose to alleviate the WD+Al stress was 50 µM MeJA due to the activation of antioxidants in blueberry plants. Therefore, the MeJA application could be a potential strategy for enhancing the resilience of V. corynbosum exposed to WD+Al stress.

Assessing temporal variability in durum wheat performance and stability through multi-trait mean performance selection in Mediterranean climate

Durum wheat, a staple crop in Italy, faces substantial challenges due to increasing droughts and rising temperatures. This study examines the grain yield, agronomic traits, and quality of 41 durum wheat varieties over ten growing seasons in Southern Italy, utilizing a randomized complete block design. Notably, most varieties were not repeated between trials and 45% of the data was missing. The results indicate that the interaction between genotype and environment (GEI) significantly impacted all traits. High temperatures, elevated vapor pressure deficit (VPD), and water deficits severely affected yield and quality during warm years, while cooler years with favorable water availability promoted better growth and higher yields. Broad-sense heritability (H²) was generally low, suggesting that environmental factors played a major role in the observed traits. However, some traits, such as grain yield, ears per square meter, plant height, bleached wheat, thousand-grain weight, and hectoliter weight exhibited moderate to high heritability of the mean genotype (h²mg), indicating their potential for effective selection in breeding programs. Correlation analyses revealed strong connections between certain traits, such as protein content, and gluten index as well as between grain yield, and spike per square meter. Using the Multi-Trait Mean Performance Selection (MTMPS) index, the study identified six top-performing varieties. Among these, Antalis (G4) and Core (G18) consistently demonstrated strong adaptability and stability across different environments, particularly in hotter, drier conditions. Furio Camillo (G31) also exhibited valuable traits. This study highlights the challenges and complexities of breeding durum wheat for improved yield and quality in the face of climate change.