Search Results (400)

Water scarcity in semi-arid regions threatens seed germination and early crop establishment, driving the development of biodegradable Nature-based Solutions to replace synthetic plastic mulches. Porous cellulose membranes were fabricated from rice husk (RH), banana pseudostem (BP), and sugarcane bagasse (SB) by thermo-chemical extraction and high-shear homogenization (n = 5 replicates per membrane type). Membranes were characterized by ATR-FTIR and scanning electron microscopy, confirming removal of non-cellulosic components and biogenic silica preservation in RH, and revealing biomass-dependent porous architectures linked to mechanical and transport behavior. RH produced the most compact fibrillar matrix (compressive strength: 8.16 ± 0.24 MPa; WVT: 170 ± 60 g m⁻² day⁻¹), BP an open interconnected network with superior deformability (9.83 ± 0.25% elongation) and moisture transport (WVT: 400 ± 100 g m⁻² day⁻¹), and SB the highest moisture-retention capacity (215.7 ± 15.8%). Germination assays with Brassica oleracea var. botrytis under water stress showed SB achieved the highest germination rate (90.5 ± 0.99%), confirming that sustained moisture availability governs germination more decisively than transport rate alone. Soil burial tests confirmed biodegradable behavior across all membranes (R² ≥ 0.995; k = 0.043–0.046 day⁻¹). These findings establish a hydrogen-bond-mediated structure–property–function framework for designing biomass-specific cellulose membranes as biodegradable solutions for water-limited agricultural systems. Full article

Dry direct seeding (DDS) is a water-saving and high-efficiency rice cultivation system. However, drought stress during DDS severely constrains seedling establishment. This study used the conventional rice variety Zhonghua 11 (ZH11) and the drought-tolerant hybrid Hanyou 73 to investigate the effects of exogenous silicon (Si) on seed germination and seedling growth under drought stress, and to explore the underlying mechanisms of Si-enhanced drought tolerance. Drought stress was imposed using PEG-6000 simulation and pot experiments with different soil relative water contents (60%, 45%, 25%, and 10%). Si treatment significantly alleviated simulated drought inhibition of seed germination, increasing germination percentage and index, improving seedling growth in both varieties. Under simulated DDS conditions, Si significantly improved plant height, biomass, and root development, while maintaining higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and chlorophyll content. Meanwhile, Si reduced oxidative damage by promoting proline accumulation, enhancing peroxidase (POD) and catalase (CAT) activities in both leaves and roots, reducing malondialdehyde (MDA) accumulation, and upregulating the expression of key drought-responsive genes (SNAC1, DREB1A, SKIPa, P5CS2). Furthermore, Si upregulated the expression of genes involved in abscisic acid (ABA) (ABA1, ABA2, MHZ5, ABI3) and jasmonic acid (JA) (AOS2, AOS3, JAR1, JAR2, MYC2, COI1a) biosynthesis and signaling. Compared with the wild-type, the ABA signaling mutant abi3 and the JA signaling mutant myc2 exhibited significantly attenuated improvement of plant growth by Si treatment. Collectively, Si enhances antioxidant capacity and osmotic adjustment, maintains photosynthetic function, and is associated with the activation of ABA and JA signaling pathways, which together alleviate the inhibition of rice seedling establishment under DDS-associated drought stress. Our findings provide a theoretical basis for the application of Si fertilizer in DDS rice production. Full article

Malaysia plans to produce 80% of its rice requirement by 2030. To achieve the plan, new agronomic approaches have to be put in place to enhance the fertility of rice soils in the country. One of the options is to turn the infertile acid sulfate soils endemic in the low-lying coastal plains of Peninsular Malaysia into a new granary area. Using traditional agro-techs, rice yield in the area is below the national average of 4 t/ha/season. The low yield is due to soil acidity stress (pH < 4) together with Al³⁺ and/or Fe²⁺ toxicity. The critical pH for rice is 6, while the respective critical Al³⁺ and Fe²⁺ concentrations are 5.2 µM and 14.6 µM. The adverse conditions contributing to yield reduction can be resolved by applying appropriate soil amendments known to raise water pH, eliminating the toxic cations. The recommended agronomic practice is to apply ground magnesium limestone (GML) or ground basalt, or better still, apply GML or ground basalt in combination with bio-fertilizer, fortified with phosphate-solubilizing bacteria (PSB). The PSB increases water pH as well as helps rice plants secrete organic acids that reduce the toxic effects of Al³⁺ and Fe²⁺ via chelation. When pH rises >5, the toxic metals are precipitated, forming inert hydroxides. Ultimately, rice yield can be increased from 3 to 5 t/ha/season, which can last more than three consecutive cropping seasons. If this agro-tech is adopted throughout ASEAN, food security in the region will be sustained. Full article

Timely and accurate assessment of rice productivity, encompassing grain yield, aboveground biomass (AGB), and harvest index (HI), is essential for harvest planning, supply chain coordination, and food security. This study evaluates the feasibility of predicting all three productivity components using satellite and weather time series data while examining trade-offs between forecast accuracy and operational lead time. Five machine learning models (CatBoost, Gaussian Process Regression (GPR), Random Forest, Ridge regression, and TabPFN) were compared across six in-season prediction windows (December to May) using Sentinel-2 vegetation indices (Normalized Difference Vegetation Index (NDVI), Chlorophyll Index Red Edge 2 (CIRE2), Land Surface Water Index (LSWI)), weather variables (minimum and maximum temperature and radiation), and agronomic records from 256 commercial and experimental rice fields in southern New South Wales, Australia, over four growing seasons (2022–2025) using leave-one-year-out cross-validation. Rolling in-season forecasts were evaluated across December–May; March was selected for further analysis as a practical window that balances accuracy and timeliness for decision-making, with minimal additional error reduction in later months closer to harvest. TabPFN had the lowest RMSE for yield prediction (RMSE = 1.85 t ha⁻¹, $r=0.72$), Ridge had the lowest RMSE for AGB (RMSE = 3.05 t ha⁻¹, $r=0.77$), while tree-based models yielded the lowest RMSE for derived HI (RMSE ≈ 0.07). HI prediction showed weak regional relationships, with direct prediction yielding $\left|r\right|\approx 0.24$ and derived HI (predicted yield divided by predicted AGB) showing $r\approx 0$. Although strong correlations ($r>0.9$) between HI and vegetation indices were observed within individual site-seasons, consistent with other studies, these relationships were highly variable across site-seasons, reflecting the difficulty of inferring HI from canopy reflectance when biotic and/or abiotic stresses decouple AGB accumulation from grain filling. Both direct and derived HI approaches yielded comparable errors, indicating that satellite and weather data lack information content for regional-scale HI prediction. These findings support satellite-based yield and AGB forecasting for operational use. Full article

Drought stress is the most pervasive abiotic constraint on global crop productivity, with projected intensification under climate change threatening the yields of staple crops including wheat, rice, maize, and legumes. Conventional breeding approaches have delivered limited gains against drought tolerance, constrained by the polygenic and multifactorial nature of stress adaptation, the complexity of genotype-by-environment interactions, and the inadequacy of field-based phenotyping under variable stress conditions. Omics technologies, including genomics, transcriptomics, proteomics, metabolomics, epigenomics, and phenomics, have substantially advanced the molecular dissection of drought tolerance by enabling high-resolution characterization of stress-responsive genes, regulatory networks, adaptive proteins, and metabolic reprogramming pathways. Specific traits targeted include root system architecture and depth, osmotic adjustment capacity through proline and glycine betaine accumulation, antioxidant defense mechanisms, ABA-mediated stomatal regulation, LEA protein accumulation, epigenetic stress memory, and yield stability under water deficit. This review systematically examines omics-based strategies for drought stress mitigation across major crops, highlighting individual omics contributions, multi-omics integration frameworks, computational tools including machine learning and AI-driven predictive modelling, and translational breeding applications. Case studies in wheat, rice, maize, and legumes illustrate how omics-driven approaches accelerate precision breeding for drought resilience through marker-assisted selection, genomic selection, and CRISPR-based gene editing. Challenges including data integration complexity, high implementation costs, limited cross-species transferability, and the need for field-scale validation of microbiome-based strategies are critically addressed. Future perspectives encompassing single-cell and spatial omics, AI-driven predictive breeding, digital agriculture integration, and international data governance frameworks are discussed. By aligning with climate-smart agriculture principles, multi-omics approaches provide a robust and transformative foundation for developing drought-resilient crop cultivars suitable for water-limited production systems worldwide. Full article

Herbicides considered selective to rice are generally evaluated based on their direct crop safety and weed suppression effects, yet it remains unclear whether they may also trigger indirect or context-dependent effects on rice under rice–barnyardgrass co-cultivation. To address this question, we compared rice performance and associated microbial dynamics under six conditions: rice–barnyardgrass co-cultivation and rice monoculture, each treated with a water spray control or sublethal doses of propanil (Pro, 66.7 mg a.i. L⁻¹) or cyhalofop-butyl (Cyh, 5.86 mg a.i. L⁻¹). Barnyardgrass exhibited visible injury and stronger leaf-level oxidative stress responses, whereas rice displayed no discernible phytotoxic symptoms. Nevertheless, under co-cultivation, herbicide treatment significantly suppressed rice growth, with up to 17.8% lower root lengths and 24.8% lower shoot fresh weights, with reductions varying by herbicide and trait. By contrast, comparable suppression was not observed under herbicide exposure or co-cultivation alone, identifying this response as an emergent, context-dependent negative effect. Microbiota reassembly emerged as an early and stage-specific component of the herbicide-associated response under co-cultivation, with the most pronounced changes detected on day 5 and occurring primarily in bacterial communities. Moreover, bacterial community variation was negatively correlated with root length (ρ = −0.664), and urease activity declined under herbicide treatment. Together, these findings indicate that in paddy fields, herbicides act not only on individual plants but also as an external disturbance to the coupled rice–barnyardgrass system, for which microbiota reorganization represents a key component of the ecological response. Our results suggest that herbicide selectivity should be interpreted within a crop–weed–microbiome context, rather than being inferred solely from their direct crop safety and weed suppression effects. Full article

Agricultural waste streams represent an underutilized source of bioactive compounds with potential to enhance crop resilience under climate stress. We previously showed that volatile compounds (VCs) emitted from waste shiitake fungi beds (WSFBs) promote early rice seedling growth under controlled conditions. Here, we evaluated whether these early-stage effects persist after transplanting and translate into agronomic benefits under field conditions, including the record high temperatures (HTs) of the 2023 growing season in Niigata, Japan. Seedlings of two japonica cultivars, Nipponbare and Koshihikari, were exposed to WSFBs-derived VCs using a non-contact system and subsequently grown in paddy fields across two seasons (2023–2024). WSFBs-VCs-treated (+VCs) plants exhibited enhanced seedling vigor, increased tiller and panicle numbers, higher grain yield per plant, greater 1000-grain weight, and reduced grain chalkiness. Gas exchange measurements at the reproductive stage during the 2023 record HT showed that +VCs plants maintained higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, and transpiration rate, while intrinsic water-use efficiency showed a modest decline consistent with transpirational cooling. Controlled-environment assays revealed enhanced physiological stability supported by upregulation of cytokinin and stress-responsive genes under acute heat stress. Together, these results demonstrate that short-term exposure to WSFBs-derived VCs enhances rice performance under field conditions, including during extreme heat, and highlight their potential as low-cost, waste-derived biostimulants that support sustainable, circular, and climate-resilient rice production. Full article

Inadequate drainage and the application of salty irrigation waterinduced salinity stress, poses a major constraint to agricultural productivity, especially in saline–arid regions. Shallow subsurface drainage has emerged as a potential technique for salinity management; however, its implications for crop physiological and biochemical responses remain unclear. Therefore, a two-year lysimetric study was undertaken in a split-split plot design investigating cut-soiler-based preferential shallow subsurface drainage (PSSD), soil type (saline sandy loam and normal silty clay loam), and irrigation water salinity levels (4, 8 and 12 dS m⁻¹) to evaluate the effectiveness of rice-residue-filled cut-soiler PSSD in mitigating salinity stress in pearl millet and mustard crops. The cut-soiler PSSD reduced root-zone salinity to around 60.0% by the end of experimentation. Lower root-zone salinity under cut-soiler PSSD alleviated osmotic and ionic stress by reducing hydrogen peroxide (11.0–14.6%), membrane injury (22.7–40.8%), lipid peroxidation (20.0–25.0%), proline accumulation (26.0–37.0%) and improving the Na⁺/K⁺ ratio (44.0%). Antioxidant enzyme activities were also significantly moderated under the cut-soiler PSSD. These physiological and biochemical improvements resulted in significant increases in grain and seed yield of pearl millet (23.5%) and mustard (31.4%), respectively. The findings of this study indicate that cut-soiler PSSD is an effective strategy to mitigate salinity stress at the physiological and biochemical level and offers sustainable management strategies for salt-affected agro-ecosystems. Full article

Soil salinization is a major constraint on irrigated rice cultivation, mainly due to poor irrigation management and cropping in coastal areas. Seed priming is widely recognized as a cost-effective and practical approach to enhance early growth and improve tolerance to abiotic stresses, including salinity. This study evaluated the effects of seed priming of rice seeds from two cultivars, BRS Querência (Indica) and BRS 358 (Japonica), using aqueous carrot root extract at 0% (water), 25%, and 50% concentrations for 48 h. Seeds were sown in rhizotrons and exposed to 0, 75, or 150 mM NaCl. Morphological, physiological, and biochemical traits were evaluated at 21 days after sowing. Seed priming with carrot extract was associated with improved growth and physiological responses under salinity stress. Under 150 mM NaCl, primed seedlings showed approximately 40% higher chlorophyll index, 35% greater root volume, and 30% higher shoot dry mass compared to unprimed controls. The 25% extract concentration was particularly effective for BRS Querência, which showed enhanced root elongation and a higher nitrogen balance index. Activities of superoxide dismutase, ascorbate peroxidase, and catalase increased by 45–70%, while hydrogen peroxide and malondialdehyde levels decreased by approximately 50%, suggesting enhanced antioxidant responses and improved redox balance. Anthocyanin accumulation also increased in specific cultivar–treatment combinations, suggesting a potential effect on secondary metabolism and antioxidant pathways. Overall, carrot-based seed priming was associated with improved seedling performance, pigment stability, and regulation of oxidative stress under saline conditions. These results suggest that carrot-based seed priming may improve physiological performance under salinity stress. Full article

Rice (Oryza sativa L.) grain quality is a critical determinant of market value, consumer acceptance, and nutritional security. This multifaceted trait is governed by the dynamic interaction of genotype (G), environment (E), and management practices (M). In this review, we synthesize recent advances in understanding these multifaceted determinants. We first delineate the genetic architecture, emphasizing key genes and quantitative trait loci (QTLs) such as Wx, ALK, Chalk5, and the GS3/GW families, which control starch composition, gelatinization temperature, chalkiness, and grain dimensions, forming the foundational blueprint for quality potential. We examine how this genetic potential is influenced by environmental factors, focusing on the detrimental impacts of abiotic stresses, particularly high temperatures during grain filling and drought, which impair milling yield, increase chalkiness, and modify starch and protein profiles. Furthermore, we discuss how optimized agronomic strategies—including precision water management (e.g., alternate wetting and drying), balanced nitrogen fertilization, and targeted micronutrient (e.g., silicon) application—can mitigate these adverse effects and potentially improve specific quality parameters. Post-harvest handling is identified as the final determinant of product quality. We conclude that achieving high and stable rice quality under climate variability requires an integrated G × E × M approach. Prospects include next-generation breeding for climate-resilient quality, precision agronomy guided by real-time sensing, synergistic soil health management, and the integration of systems biology with digital agriculture to design sustainable, high-quality rice production systems. Full article

Drought stress is a major abiotic constraint to rice productivity. Seedling-stage screening of rice genotypes is therefore essential for identifying key adaptive traits and drought-tolerant genotypes. This study evaluated 40 lowland rainfed rice genotypes for seedling-stage drought tolerance under greenhouse conditions using a split-plot randomized complete block design. Progressive drought stress was imposed for 21 days, and root and shoot traits were assessed. Substantial morphological variability was observed among genotypes for most traits. Drought stress significantly reduced root dry weight (52.8%), shoot dry weight (51.6%), seedling biomass (51.5%), number of roots (39.3%), number of roots with at least 5 cm length (37%), and shoot length (21.1%). Root-to-shoot ratio showed significant water × genotype interaction. Correlation analysis, heritability, and genetic advance identified root traits as reliable selection criteria for seedling-stage drought stress screening. Combined Drought Stress Response Index (CDSRI) classified 17.5% of genotypes as tolerant and 12.5% as sensitive. Tolerant genotypes (B1P15, Chupa, Mucabo, Mpulo, Nasoco, Nene, and Mutanzania) represent a valuable resource for rice breeding targeting early-season drought resilience. These findings support breeders in identification of adaptive traits and provide a basis for policy interventions to invest in drought-resilient varieties that benefit farmers in rainfed areas. Full article

Salinity stress severely limits rice productivity and grain quality worldwide. Although exogenous foliar application of titanium dioxide nanoparticles (nano-TiO₂) has been reported to enhance crop stress tolerance, its regulatory roles in yield formation and grain quality in rice varieties with differing salt tolerance are not well understood. In the present study, two contrasting rice varieties, viz., Jingliangyou 3261 (JLY3261; salt-tolerant) and Yuxiangyouzhan (YXYZ; salt-sensitive), were applied with five nano-TiO₂ foliar application treatments—viz., CK: water spray; Ti1: 15 mg L⁻¹; Ti2: 30 mg L⁻¹; Ti3: 45 mg L⁻¹; and Ti4: 60 mg L⁻¹—at the jointing and panicle initiation stages. Plants were irrigated with 0.3% saltwater to simulate salt stress. The results showed that Ti2 and Ti3 treatments led to 8.59% and 14.80% increases in grain yield in JLY3261 and YXYZ, respectively, compared with CK. Ti2 and Ti3 treatments significantly increased the leaf area index, net photosynthetic rate, and aboveground biomass of both varieties at the heading stage. Meanwhile, the activities of antioxidant enzymes such as superoxide dismutase and peroxidase, as well as nitrogen metabolism enzymes including nitrate reductase and glutamine synthetase, were improved with a substantial reduction in malondialdehyde contents. Application of nano-TiO₂ upregulated the expression of ion transport-related genes such as OsSOSs, OsNHXs and OsHKTs, thus improving leaf K⁺ accumulation and reducing Na⁺ content to optimize the K⁺/Na⁺ ratio. In addition, Ti2 and Ti3 treatments improved the milled rice rate, head rice rate, and protein content, while they decreased the chalkiness degree of both rice cultivars. Principal component analysis showed that the aboveground biomass at the heading stage was a core evaluation index for both varieties. Overall, foliar application of 30–45 mg L⁻¹ nano-TiO₂ was found to be effective regarding growth and yield improvement in rice under saline conditions. This study provides a theoretical basis for agro-management strategies for rice cultivation in saline–alkaline soils. Full article

Anaerobic germination tolerance (AGT) is a critical adaptive trait for rice establishment in flood-prone environments and direct-seeded systems. Here, we identified and validated the quantitative trait locus qAG2.1 for AGT and introgressed it into the elite lowland rice variety CR Dhan 801 through marker-assisted backcross breeding. The introgressed lines exhibited significantly improved germination under anaerobic conditions, demonstrating the effectiveness of qAG2.1 in a high-yielding genetic background. While CR Dhan 801 showed a low anaerobic germination percentage (17.6%), the donor ARC10424 exhibited 82.6%, and the best-performing introgressed line (22009-3) achieved 49.2%. Importantly, the improved lines maintained agronomic performance comparable to CR Dhan 801 under non-stress conditions, indicating minimal yield penalty. To gain mechanistic insight, the qAG2.1 interval was dissected in silico to prioritise candidate genes putatively associated with AGT. This analysis highlighted genes linked to ethylene biosynthesis and signalling (e.g., OsACO3, OsERF109), abscisic acid biosynthesis (OsNCED1), gibberellin homeostasis (OsGA2ox9), trehalose metabolism (OsTPS5, OsTPP1), detoxification of anaerobic by-products (OsALDH2A), and water transport (OsPIP1;3). Collectively, these results validate qAG2.1 as a further deployable locus for improving anaerobic germination in elite rice backgrounds and provide a set of putative candidate genes for future functional characterisation. Full article

Plants adapt to abiotic stresses by modulating morphological, physiological, and biochemical processes, which constitute the fundamental mechanisms of stress tolerance. Rice is highly susceptible to drought stress at all developmental stages, leading to substantial reductions in growth and yield, signifying the urgent need to develop drought-tolerant rice genotypes. In this study, recombinant inbred lines (RILs) in rice with enhanced drought tolerance were developed through a cross between the high-yielding rice variety BRRI-28 and the commercial variety BINA-7, followed by successive selfing and phenotypic selection. The resulting lines were evaluated using integrated morphological, physiological, biochemical, and anatomical analyses under well-watered (WW) and drought conditions (DC). BRRIdhan-56, a known drought-tolerant variety, was included as a check genotype. Among the tested lines, RIL-3 exhibited superior agronomic performance under DC, including a significantly higher tiller number, plant height, and seed dry weight, and improved root attributes compared with its parental lines and, for several traits, exceeding those of BRRIdhan-56. Leaf rolling was absent in RIL-3 and the check variety until the 23rd day of drought stress, whereas other genotypes exhibited varying degrees of stress symptoms. Panicle exertion under DC was observed exclusively in RIL-3 and the check. Although all genotypes showed reductions in biomass, relative water content, and chlorophyll levels under DC, RIL-3 consistently maintained higher values than its parental lines and comparable or superior levels to the check variety. Notably, RIL-3 exhibited a distinctive physiological response characterized by sustained chlorophyll retention and low proline accumulation under severe drought, in contrast to the high proline levels observed in sensitive lines. A root anatomical analysis further revealed well-developed aerenchyma formation in RIL-3 following drought treatment, supporting its drought tolerance. Together, these results demonstrate that RIL-3 combines an enhanced drought tolerance with a stable agronomic and yield-related performance and a unique physiological trait profile under drought stress, highlighting its potential value as a promising genotype for drought-tolerance breeding programs. Full article

Ultrafine bubble (UFB)-enriched water promotes plant growth when nutrients are present. A key question is whether it can still encourage growth in the absence of nutrients. Therefore, this study examines how different UFB concentrations affect the early growth and development of rice seedlings under nutrient-free conditions where external nutritional application was excluded. The results showed that the examined morphological and physicochemical parameters were directly affected by the bubble concentration in the irrigation water. Higher bubble concentrations resulted in a significant increase in the fresh and dry weights of roots, primary and secondary root lengths, and specific root length. Similarly, higher bubble concentrations were also associated with greater shoot height, fresh weight, and dry weight. However, pigment concentrations were not clearly affected, except for anthocyanin. Hydrogen peroxide concentration increased proportionally with bubble concentration. Among the antioxidant enzymes assessed, peroxidase activity increased significantly with bubble concentration, whereas the other antioxidant enzymes showed no significant variation. Moreover, UFB irrigation significantly affected carbon metabolism, increasing soluble sugar content while reducing storage starch levels. In conclusion, the findings suggest that UFB-enriched irrigation can promote plant growth under nutrient-free external conditions by modulating stress-related molecules, activating antioxidant enzymes, and altering carbon metabolism. Full article