Water-limited Conditions Research Articles

Organic Fertilization and Melatonin: Improving Crisphead Lettuce Performance in Water-Limited Conditions

Organic Fertilization and Melatonin: Improving Crisphead Lettuce Performance in Water-Limited Conditions

Impact of No Tillage and Low Emission N Fertilization on Durum Wheat Sustainability, Profitability and Quality

Mitigation practices for cereal systems, including conservation agriculture and low emission fertilization, are required to face global challenges of food security and climate change. The combination of these climate-smart approaches was investigated for durum wheat in a dry region of the Mediterranean basin in two crop seasons. The experimental design consisted in two different genotypes, Marco Aurelio (high protein content) and Saragolla (higher adaptability), subjected to no tillage (NT) vs. conventional tillage (CT) and to two fertilization strategies (standard vs. low emission plus an unfertilized control). Different environmental and economic sustainability parameters as well as two different technological and nutritional quality traits were evaluated. Saragolla showed a better environmental adaptability and a higher nitrogen use efficiency, evaluated as partial nutrient balance (+27%), and was associated with a lower protein content (14.5% vs. 15.6%). NT was associated with an improvement in yield (+15%) and quality, i.e., micronutrients (Fe, Zn) and antioxidant capacity (+15%), in the drier crop year. Low emission fertilization did not reduce crop performance and its combination with NT showed a higher economic net return. The combination of the two mitigation practices improved not only environmental and economic sustainability but also the health quality of durum wheat under water limited conditions.

Optimized Irrigation Strategies for Saline Soil Remediation in Agricultural Lands Under Water-Limited Conditions

Soil salinization is a prevalent global issue, significantly impacting crop cultivation and food production. This study investigates the potential of sustainably harnessing rainwater for the remediation of saline soils in water-scarce regions. Soil column leaching experiments were performed to evaluate the effectiveness of different methods for salt removal from the tillage layer. The findings demonstrated that intermittent leaching was more effective than continuous leaching in remediating NaCl-type saline soils. When continuous leaching with 27 cm of rainwater was applied, the salt removal in soil layers below 5 cm ranged from 12.28% to 26.86%. Intermittent leaching increased the salt removal rate to between 44.49% and 54.18%. This higher desalination efficiency of intermittent leaching is attributable to the extended soil–water contact time. When the leaching time in continuous leaching was increased from 1.5 h to over 4.5 h, comparable desalination effects were produced. The rainwater leaching demonstrated similar salt removal patterns in Na2SO4-type saline soils. However, due to the stronger affinity of SO42− for clay particles, their effluent concentration and removal were lower than Cl− under the same conditions. To optimize desalination efficiency, operational parameters can be adjusted to reduce the leaching depth of rainwater from 27 cm to 15 cm, and the interval between leaching events from 24 h to 4.5 h. The findings of this study may serve as a valuable reference for saline soil restoration and improvement efforts in water-scarce regions.

Evaluating Physiological and Yield Indices of Egyptian Barley Cultivars Under Drought Stress Conditions

Climate change significantly threatens crops, mainly through drought stress, affecting barley, which is essential for food and feed globally. Ten barley cultivars were evaluated under normal and drought stress conditions during the 2019/20 and 2020/21 seasons, focusing on traits such as days to heading and maturity, plant height, number of spikes m−2, spike length, 1000-kernel weight, and biological and grain yield. Drought stress significantly reduced most of these traits. The genotypes showed significant differences in their responses to irrigation treatments, with the interaction between seasons and cultivars also being significant for most traits. The grain yield and 1000-kernel weight were among the least affected traits under drought stress, respectively. Notably, Giza138 and Giza126 showed strong drought tolerance, suitable for drought-resilient breeding. In season one, Giza126, Giza134, and Giza138 yielded 13%, 9%, and 11%, respectively, while Giza135 and Giza129 showed higher reductions at 31% and 39%. In season two, Giza126, Giza134, and Giza138 had reductions of 14%, 10%, and 13%, respectively, while Giza135 and Giza129 again exhibited higher reductions at 31% and 38%. These cultivars also showed strong performance across various stress tolerance indices, including the MP, YSI, STI, GMP, and YI. Giza 134 demonstrated the lowest values for the SDI and TOL, indicating superior drought stress tolerance. On the other hand, Giza 129 and Giza 135 were the most sensitive to drought stress, experiencing significant reductions across critical traits, including 6.1% in days to heading, 18.37% in plant height, 28.21% in number of kernel spikes−1, 38.45% in grain yield, and 34.91% in biological yield. In contrast, Giza 138 and Giza 2000 showed better resilience, with lower reductions in the 1000-kernel weight (6.41%) and grain yield (10.61%), making them more suitable for drought-prone conditions. Giza 126 and Giza 132 also exhibited lower sensitivity, with minimal reductions in days to heading (2%) and maturity (2.4%), suggesting potential adaptability to water-limited environments. Giza 126 maintained the highest root lengths and had the highest stomatal conductance. Giza 138 consistently had the highest chlorophyll content, with SPAD values decreasing to 79% under drought. Despite leading in shoot length, Giza 135 decreased to 42.59% under drought stress. In conclusion, Giza 126 and Giza 138 showed adaptability to water-limited conditions with minimal impact on phenological traits. Giza 126 had the longest roots and highest stomatal conductance, while Giza 138 consistently maintained a high chlorophyll content. Together, they and Giza 134 are valuable for breeding programs to improve barley drought tolerance.

Chemical activation of ABA signaling in grapevine through the iSB09 and AMF4 ABA receptor agonists enhances water use efficiency.

Grapevine (Vitis vinifera L.) is the world's third most valuable horticultural crop, and the current environmental scenario is massively shifting the grape cultivation landscape. The increase in heatwaves and drought episodes alter fruit ripening, compromise grape yield and vine survival, intensifying the pressure on using limited water resources. ABA is a key phytohormone that reduces canopy transpiration and helps plants to cope with water deficit. However, the exogenous application of ABA is impractical because it suffers fast catabolism, and UV-induced isomerization abolishes its bioactivity. Consequently, there is an emerging field for developing molecules that act as ABA receptor agonists and modulate ABA signaling but have a longer half-life. We have explored the foliar application of the iSB09 and AMF4 agonists in the two grapevine cultivars cv. 'Bobal' and 'Tempranillo' to induce an ABA-like response to facilitate plant adaptation to drought. The results indicate that iSB09 and AMF4 act through the VviPYL1-like, VviPYL4-like, and VviPYL8-like ABA receptors to trigger stomatal closure, reduce plant transpiration, and increase water use efficiency. Structural and bioinformatic analysis of VviPYL1 in complex with ABA or these agonists revealed key structural determinants for efficient ligand binding, providing a mechanistic framework to understand receptor activation by the ligands. Physiological analyses further demonstrated that iSB09 has a more sustained effect on reducing transpiration than ABA, and agonist spraying of grapevine leaves protected PSII during drought stress. These findings offer innovative approaches to strengthen the vine's response to water stress and reduce plant consumptive water use under limited soil water conditions.

Tree species and drought: Two mysterious long-standing counterparts.

Around 252 million years ago (Late Permian), Earth experienced one of its most significant drought periods, coinciding with a global climate crisis, resulting in a devastating loss of forest trees with no hope of recovery. In the current epoch (Anthropocene), the worsening of drought stress is expected to significantly affect forest communities. Despite extensive efforts, there is significantly less research at the molecular level on forest trees than on annual crop species. Would it not be wise to allocate equal efforts to woody species, regardless of their importance in providing essential furniture and sustaining most terrestrial ecosystems? For instance, the poplar genome is roughly quadruple the size of the Arabidopsis genome and has 1.6 times the number of genes. Thus, a massive effort in genomic studies focusing on forest trees has become inevitable to understand their adaptation to harsh conditions. Nevertheless, with the emerging role and development of high-throughput DNA sequencing systems, there is a growing body of literature about the responses of trees under drought at the molecular and eco-physiological levels. Therefore, synthesizing these findings through contextualizing drought history and concepts is essential to understanding how woody species adapt to water-limited conditions. Comprehensive genomic research on trees is critical for preserving biodiversity and ecosystem function. Integrating molecular insights with eco-physiological analysis will enhance forest management under climate change.

Integrating genomics with crop modelling to predict maize yield and component traits: Towards the next generation of crop models

Conventional breeding of ideotypes for target environments is quite challenging because of the genotype by environment interaction and the nature of the genetic complexity for economic traits. Simulation of the adaptive capacity of existing and new germplasms using crop model and genetic information can efficiently assist in determining the potential of well-adapted genotypes for target environments. This study aimed to design a marker-based model by detecting associated markers for target traits associated with model input parameters and incorporating the genetic effects into the CERES-Maize model. To achieve this goal, a two-year trial with 282 maize genotypes across five locations in Northern China was conducted for phenotypic and genotypic data collection. The marker effects on target traits were integrated with crop model to develop a marker-based model. The performance of the integrated model was tested using four independent sub-datasets, (i) observed genotypes grown in observed environments; (ii) observed genotypes phenotyped in new environments; (iii) new genotypes in characterized environments; and (iv) new genotypes in new environments. The model simulated the anthesis date, kernel number, kernel weight and yield reasonably well across 282 genotypes. The marker-based prediction performance of simpler morphological traits, such anthesis date and kernel number were generally improved compared to highly complex quantitative traits, such as kernel weight and yield. The performance of the model was affected by new genotypes or new environments depending on the types of traits being simulated. Maker-based simulation of maize yield and its component traits across five locations and 37 years in Northern China was used as a case study to demonstrate the model applications for studying genotype–environment interactions. The biplot revealed the top yielding genotypes and most ideal environment by comparing yield performance and stability of 282 genotypes in five phenotyping sites under both water-limited and well-water conditions. Breeding programs could further exploit marker-based modelling to predict adaptation in diverse environmental and management conditions for new genotypes before they are globally distributed for multilocation yield testing.

Handmade wastepaper conversion into nanourea incorporated carboxymethylcellulose hydrogel as fertilizer release vehicle for augmenting plant growth

The concept of utilizing handmade wastepaper refuse for synthesis of nanocellulose and later converting it into nanourea incorporated carboxymethylcellulose (NU@CMC) hydrogel has been visualized as a sustainable solution to manage solid wastepaper and simultaneously enrich plant growth by providing nanourea. Various characterization techniques like Fourier-transform infrared spectroscopic (FTIR), Field emission scanning electron microscopic (FESEM), High-Resolution Transmission Electron Microscopy (HRTEM) analysis and Brunauer-Emmett-Teller (BET) analysis confirmed that the NU@CMC hydrogel was rich in functional groups, having porous and rough surface morphology. Swelling ratio was found to be 1457% at pH 7 due to the presence of polar group and porous surface of hydrogel. Maximum water holding capacity (54.45%) was obtained at 2 wt% NU@CMC hydrogels, and it retained moisture in the soil for more than 2 weeks. NU@CMC hydrogel was used as a control release vehicle for the release of nanourea for plants at different pH ranges, and results indicated that this process followed the Fickian diffusion mechanism at pH 7 and 46.71% release efficiency was observed in 18 days. Maximum stem length was observed with NU@CMC hydrogels compared to CMC hydrogel and soil. Thus, eco-friendly, versatile NU@CMC hydrogel with 39.8% biodegradability within 32 days establishes its dual promise for water transport under water-limited conditions and as a fertilizer release vehicle for sustainable plant growth.

Energy budgeting, carbon footprint and economics of sunflower and pigeonpea system under moisture conservation practices in rainfed semi-arid tropics

In drylands, soil water availability in the profile during crop period, especially at critical stages is most vital. System which is productive, energy efficient with a minimum carbon (C) footprint under limited water condition is a concern. Therefore we evaluated sunflower and pigeonpea crops over two-years in terms of productivity, energy, C-footprint and profitability under different moisture conservation measures. These were raised bed, ridge and furrow, tied ridges and furrow, conservation tillage, flatbed sowing and opening furrow after every three rows at 30 days, and flatbed sowing under sole crops of sunflower and pigeonpea and intercropping at 1:1 adopted split-plot design. The results showed in-field moisture conservation by ridge and furrow produced considerably greater sunflower (59.6–66%) and pigeonpea (85.2–128.7%) yields and profitable (604.1 US$ ha−1) over traditional flatbed sowing. It also exhibited greater output energy (37.8–83.0%), energy use efficiency(4.2 kg GJ−1),and lower energy intensity (21.57 × 10−3 GJ US$−1). Sunflower and pigeonpea sole crops produced higher seed yields over intercropping. But it has yield advantage in terms of greater pigeonpea equivalent yield (0.53–1.13 Mg ha−1), profitability (691.8 USD ha−1), output energy (42.4 GJ ha−1) and energy ratio. Among the input energy sources, chemical fertilizers accounted 53.6 % of the total input energy. Interestingly, least C-footprints were recorded under ridge and furrow (182 kg CE kg−1grain)and intercropping (0.248 kg CE kg−1 grain). Results confirmed sunflower and pigeonpea intercropping on ridge and furrow was productive, energy saving, C-footprint reduction and economical practice under rainfed condition.

The rhizosphere bacterial community of water yam (Dioscorea alata L.) under limited water conditions

AbstractIntroductionYam cultivation in West Africa, the largest yam production area, has expanded to the northern Guinea savanna, which receives an annual rainfall of 800–1000 mm. However, variations in rainfall are problematic for the stable productivity of yams. Integrated soil fertility management is urgently needed to improve and stabilise yam productivity. Plants have complex interactions with bacterial communities, influencing their health and environmental adaptability. Although the growth of water yams (Dioscorea alata L.) at various rainfall levels might be related to their interaction with the bacterial community, their structure under water limitation is yet to be elucidated. Here, we evaluated the bacterial community structure in the rhizosphere (Rh) and roots of ‘A‐19’ under water limitation conditions.Materials and MethodsPlants were grown under normal conditions, and watering was reduced to less than 70% for 1 month. Rh and root samples were collected for DNA extraction, and downstream amplicon sequencing analyses were performed.ResultsThe dry weight of the shoots, particularly the leaves, decreased under water limitation. Bacterial diversity in the rhizocompartments was significantly reduced. However, bacterial community composition was not affected by water limitation. Despite water‐limited conditions, bacterial community structure was robust in the Burkholderia‐Caballeronia‐Paraburkholderia and Streptomyces clades. These taxa accounted for approximately 60% of the relative abundance in the roots under water limitation.Conclusionidentifying bacterial community composition of ‘A‐19’ under water‐limited conditions provides fundamental information for developing integrated soil fertility management strategies across rainfall gradients in West Africa. Our study indicates that ‘A‐19’ has a robust bacterial community structure for beneficial interactions with bacteria despite soil water conditions.

Pharmaceutical and personal care products in recycled water for edible crop irrigation: Understanding the occurrence, crop uptake, and water quantity effects

Global water scarcity poses a great challenge to agriculture productivity. Recycled water offers a promising alternative for agricultural irrigation, yet residual pharmaceutical and personal care products (PPCPs) in recycled water can transfer to edible crops during irrigation, and adversely affect food safety. Furthermore, irrigation water quantity can influence the accumulation of PPCPs in edible crops. This study comprehensively investigates the use of recycled water for agricultural irrigation by critically reviewing three key components: PPCPs occurrence in recycled water, their accumulation in edible crops, and the impact of water quantity on PPCPs accumulation. Literature analysis showed that PPCPs were present from 130 to 1400 ng/L in secondary effluent and 25–400 ng/L in tertiary effluent, with sulfamethoxazole being the most prevalent in both effluents. PPCPs uptake and accumulation varied between leafy and fruity vegetables, with diclofenac accumulating highest in leafy vegetables and fluoxetine in fruity vegetables. Furthermore, the water requirement of leafy and fruity crops vary throughout the growing season. In leafy vegetables, PPCPs accumulation in leaves is influenced by transpiration rate, with reduced accumulation occurring under limited water availability due to slower transpiration. In fruity vegetables, osmotic adjustment drives the water transport in fruits, leading to increased PPCPs accumulation under limited water conditions. This study contributes insights into PPCPs occurrence, accumulation, and irrigation water quantity, aiding in the development of effective strategies for recycled water use in agriculture.

Exogenous Melatonin Alleviates Osmotic Stress by Enhancing Antioxidant Metabolism, Photosynthetic Maintenance, and Hormone Homeostasis in Forage Oat (Avena sativa) Seedlings

Melatonin (MT) is a multifunctional hormone that enhances crop resilience against various abiotic stresses. However, its regulatory mechanism of osmotic tolerance in forage oats (Avena sativa) plants under water-limited scenarios is still unclear. This study aimed to delineate the impact of MT pretreatment on the morphological, physiological, and biochemical functions of oat seedlings under osmotic stress. Our findings demonstrated that exogenous treatment of MT noticeably elevated leaf area while decreasing the root/shoot ratio of oat seedlings subjected to osmotic stress. Osmotic-induced 38.22% or 48.37% decrease in relative water content could be significantly alleviated by MT pretreatment on day 7 or day 14, respectively. MT treatment also significantly mitigated osmotic-induced decreases in photosynthetic parameters including net photosynthetic rate, stomatic conductance, and intercellular CO2 concentration as well as various chlorophyll fluorescence parameters, which could contribute to enhanced accumulations of free proline and soluble sugars in seedlings after being subjected to a prolonged duration of osmotic stress. Furthermore, MT markedly improved antioxidant enzyme activities including superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase along with the accumulation of ascorbic acid contributing to a significant reduction in reactive oxygen species under osmotic stress. In addition, the MT application induced a 978.12%, 33.54%, or 30.59% increase in endogenous MT, indole acetic acid, or gibberellic acid content under osmotic stress but did not affect the accumulation of abscisic acid. These findings suggest that an optimal concentration of MT (100 μmol·L−1) could relieve osmotic stress via improvement in osmotic adjustment, the enzymatic antioxidant defense system, and endogenous hormonal balance, thereby contributing to enhanced photosynthetic functions and growth of oat seedlings under water-limited conditions.

Jarosite formation in Permian-Triassic strata at Xiakou (South China): Implications for jarosite precipitation from H2S upwelling on Mars

Abstract The source of sulfuric acid and associated aqueous alteration of ancient martian sedimentary rocks remain under debate in the context of divergent models of jarosite formation. Here, we report the formation of sulfates, including jarosite in K-bentonites within shallow-water facies of the Permian-Triassic (P-T) transition at Xiakou in South China. In these strata, jarosite is dispersed in the clay matrix or forms aggregates in pore spaces, has a euhedral morphology, and coexists with variably 34S-depleted paragenetic gypsum and bassanite (δ34S = –37.23‰ to +3.20‰ VCDT). Subaqueous alteration of volcanic tuffs concurrently with oxidation of upwelled, biogenically sourced H2S is the process of jarosite formation in the Xiakou K-bentonites. This mechanism of jarosite precipitation and stability over geological time challenges the long-held view of acidic, water-limited conditions leading to iron(III) sulfate precipitation and would be consistent with possible microbial or nanobial life on early Mars.

Phenotyping for Effects of Drought Levels in Quinoa Using Remote Sensing Tools

Drought is a principal limiting factor in the production of agricultural crops; however, quinoa possesses certain adaptive and tolerance factors that make it a potentially valuable crop under drought-stress conditions. Within this context, the objective of the present study was to evaluate morphological and physiological changes in ten quinoa genotypes under three irrigation treatments: normal irrigation, drought-stress followed by recovery irrigation, and terminal drought stress. The experiments were conducted at the UNSA Experimental Farm in Majes, Arequipa, Peru. A series of morphological, physiological, and remote measurements were taken, including plant height, dry biomass, leaf area, stomatal density, relative water content, selection indices, chlorophyll content via SPAD, multispectral imaging, and reflectance measurements via spectroradiometry. The results indicated that there were numerous changes under the conditions of terminal drought stress; the yield variables of total dry biomass, leaf area, and plant height were reduced by 69.86%, 62.69%, and 27.16%, respectively; however, under drought stress with recovery irrigation, these changes were less pronounced with a reduction of 21.10%, 27.43%, and 17.87%, respectively, indicating that some genotypes are adapted or tolerant of both water-limiting conditions (Accession 50, Salcedo INIA and Accession 49). Remote sensing tools such as drones and spectroradiometry generated reliable, rapid, and precise data for monitoring stress and phenotyping quinoa and the optimum timing for collecting these data and predicting yield impacts was from 79–89 days after sowing (NDRE and CREDG r Pearson 0.85).

Water deficit affects the nitrogen nutrition index of winter wheat under controlled water conditions

Nitrogen (N) uptake is regulated by water availability, and a water deficit can limit crop N responses by reducing N uptake and utilization. The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status. The nitrogen nutrition index (NNI) has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application. The decline of NNI under water-limiting conditions has been documented, although the underlying mechanism governing this decline is not fully understood. This study aimed to elucidate the reason for the decline of NNI under water-limiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments. Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N (75 and 225 kg N ha-1, low N and high N) and water (120 to 510 mm, W0 to W3) co-limitation treatments. Plant N accumulation, shoot biomass (SB), plant N concentration (%N), soil nitrate-N content, actual evapotranspiration (ETa), and yield were recorded at the stem elongation, booting, anthesis and grain filling stages. Compared to W0, the W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%, 12.6 to 24.8%, 14 to 24.8%, and 16.8 to 24.8% at stem elongation, booting, anthesis, and grain filling, respectively, across the 2018-2021 seasons. This decline in NNI under water-limiting conditions stemmed from two main factors. First, reduced ETa and SB led to a greater critical N concentration (%Nc) under water-limiting conditions, which contributed to the decline in NNI primarily under high N conditions. Second, changes in plant %N played a more significant role under low N conditions. Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions, indicating co-regulation by SB and the soil nitrate-N content. However, this regulation was influenced by water availability. Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability. Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants, leading to a positive correlation between plant N accumulation and ETa across the different water-N interaction treatments. Therefore, considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions. The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.

Enhanced root system architecture in oilseed rape transformed with Rhizobium rhizogenes

Transformation of plants using wild strains of agrobacteria is termed natural transformation and is not covered by GMO legislation in e.g. European Union and Japan. In the current study, offspring lines (A11 and B3) of Rhizobium rhizogenes naturally transformed oilseed rape (Brassica napus) were randomly selected to characterize the morphological traits, and analyze the implications of such morphological changes on plant drought resilience. It was found that the introduction of Ri-genes altered the biomass partitioning to above- and under-ground parts of oilseed rape plants. Compared to the wild type (WT), the A11 and B3 lines exhibited 1.2–4.0 folds lower leaf and stem dry weight, leaf area and plant height, but had 1.3–5.8 folds greater root dry weight, root length and root surface area, resulting in a significantly enhanced root: shoot dry mass ratio and root surface area: leaf area ratio. In addition, the introduction of Ri-genes conferred reduced stomatal pore aperture and increased stomatal density in the B3 line, and increased leaf thickness in A11 line, which could benefit plant drought resilience. Finally, the modulations in morphological traits as a consequence of transformation with Ri-genes are discussed concerning resilience in water-limited conditions. These findings reveal the potential of natural transformation with R. rhizogenes for drought-targeted breeding in crops.

Exotic alleles from the wild Hordeum spontaneum contribute to drought tolerance and grain quality in modern Hordeum vulgare

Conventional breeding relies on genetic variability in crop germplasm and wild species. This study evaluated 137 barley Recombinant Chromosome Substitution Lines (RCSLs), originating from crossing a drought and salinity-tolerant wild Hordeum spontaneum with the high-quality malting H. vulgare cv. Harrington. The objectives of this work were to i) improve understanding of the genetic diversity and introgression levels in RCSLs using a comprehensive set of high-density single nucleotide polymorphism (SNP) markers; ii) investigate the phenotypic variability of physiological, agronomic, and malting quality traits in RCSLs under rainfed and fully irrigated conditions; iii) unravel the relationship between these traits and the resilience of crops in drought-prone regions; and iv) identify specific SNPs associated with both drought tolerance indices and malting quality traits. Variability in physiological, agronomic, and malting quality traits was examined under rainfed and irrigated conditions, aiming to identify specific SNPs associated with both drought tolerance indices and malting quality traits. Additionally, a subset of three recombinant lines and the parent cv. Harrington was tested in growth chambers under well-watered and water-limited conditions. Agronomic traits were influenced by genotype-by-environment interaction, with notable drought tolerance lines. The grain yield was significantly correlated with yield-related traits and carbon isotope discrimination in grains. Drought stress impacted agronomic and physiological traits, with a strong reduction in leaf gas exchange and chlorophyll and protein content. The H. spontaneum genome introgression into H. vulgare cv. Harrington varied across 137 RCSLs, averaging 13.0 %. Associations between traits and genetic markers were found, particularly for the stress tolerance index in chromosome 1H and for grain quality traits (alfa-amylase, wort color, and protein) in chromosomes 1H, 4H, and 5H. These findings uncovered valuable barley RCSLs that demonstrate drought tolerance, offering promising prospects for breeding programs targeted at improving stress resilience.

Sorghum landraces perform better than a commonly used cultivar under terminal drought, especially on sandy soil

Landraces of sorghum [Sorghum bicolor (L.) Moench] have a high potential for drought adaptations to increasingly extreme climates. We investigated the performance of five sorghum genotypes (four landraces and one commonly grown elite line) under water-limited conditions. Plants were grown until maturity in field-like columns on soils of four textures (silty clay, sandy loam, loamy sand, sand), which were dried during flowering stage down to 30 % usable field capacity. Plant transpiration, physiological characteristics, and yield were measured. For most of the measured parameters, the interaction between genotypes and soils was statistically significant. Alongside the gradient in available water between soils, plants had the highest total transpiration, transpiration efficiency (TE), harvest index (HI), and nutrient uptake in silty clay, steadily reduced towards soils with higher sand content. Especially in sandy soil, all measured plant performance parameters were significantly reduced compared to the other soils. There was a significant negative relationship between later flowering time and HI. While the elite cultivar M35–1 showed the highest TE, it suffered from late flowering and yield loss on all soils, especially when growing on sandy soil. The landraces IS 29914 and IS 8348 had a stable HI irrespective of their lowest TE. The shorter the plant, the better it coped with water and nutrient limitation and high transpiration efficiency was not connected to water conservation. The study overall emphasizes the high potential of sorghum landraces to overcome more extreme droughts as imposed by climate change. It also underlines the importance and strong interaction effect of soil texture on plant performance and transpiration efficiency, which is crucial to be considered in crop production. This outlines that specifically regions with sandy soils, characterized by low water-holding capacities, need genotypes that efficiently utilize the limited available water and nutrient resources – a genetic potential hidden in many landraces.

ZmDST44 Gene Is a Positive Regulator in Plant Drought Stress Tolerance.

Improving drought tolerance in plants is essential for increasing crop yields under water-limited conditions. In this study, we investigated the functional role of the maize gene ZmDST44, which is targeted by the miRNA ZmmiR139. Our results indicate that ZmmiR139 regulates ZmDST44 by cleaving its mRNA, as confirmed by inverse expression patterns and 5'-RACE analysis. Overexpression of ZmDST44 in Arabidopsis, rice, and maize resulted in significant enhancements in drought tolerance. Transgenic plants exhibited reduced malondialdehyde (MDA) levels, increased proline accumulation, and upregulation of drought-responsive genes compared to wild-type plants. Transgenic Arabidopsis and rice showed improved drought resistance and higher post-drought recovery rates, and transgenic maize displayed lower sensitivity to drought stress. These findings suggest that ZmDST44 acts as a positive regulator of drought tolerance across different plant species and holds promise for developing drought-resistant crops through genetic engineering.

Growth, yield, and fiber quality of cotton plants under drought stress are positively affected by seed priming with potassium nitrate

Growth, productivity, and fiber quality of cotton (Gossypium hirsutum L.), a vital fiber-producing cash crop, are severely affected under drought conditions. Seed priming has a proven role in enhancing crop tolerance to abiotic stress, including drought. The objective of this study was to evaluate the effects of seed priming with KNO3 on cotton productivity and fiber quality under drought stress. A germination experiment was established under laboratory conditions with five treatments of seed priming (non-primed or control treatment, hydropriming, and priming with 2.5, 5.0, and 7.5 g KNO3 L−1). Another experiment under polyhouse conditions based on the same seed priming treatments was conducted under three levels of soil water contents (field capacity [FC] 100%: FC100, 75%: FC75, and 50%: FC50). The results obtained showed that there was a clear reduction in the different parameters tested at FC50 in comparison to FC100 (39–54%, 32–44%, 6–12%, and 7–12% reduction for boll number per plant, seed cotton yield, fiber strength, and leaf relative water content, respectively, across all priming treatments). Seed priming with KNO3 at 5 g L−1 effectively alleviated the detrimental effects originated from drought stress and caused 61–73%, 13–16%, and 16–23% increase in seed cotton yield, fiber length, and fiber strength, respectively, across soil moisture levels when compared with the control treatment. The same KNO3 dose caused an increase of 78% in water productivity in comparison to the control plants at FC50. Priming cotton seeds with 5 g KNO3 L−1 holds promise to obtain synchronized germination, enhance fiber quality, and increase yield, especially under water-limited conditions, thereby promoting economic viability and environmental sustainability. Additionally, this practice enhances water productivity, leading to significant water savings and reduced irrigation costs for cotton farmers. This method could be used as potential technology in advancing sustainable agriculture in water-constraint conditions.