Search Results (45)

Excessive chemical fertilization in maize production has reduced fertilizer-use efficiency and increased pressure on soil quality, whereas reducing fertilizer input without yield loss remains challenging. This challenge has shifted attention toward strategies that improve crop nutrient acquisition and utilization under lower fertilizer supply. Harpin protein-based enzyme complexes may provide a regulatory approach, but their field performance under reduced fertilization remains unclear. A two-year field experiment was conducted from 2023 to 2024 using two maize cultivars, Heyu236 and Fuyuan2. In 2023, the harpin protein-based enzyme complex was applied at 200-fold and 300-fold dilutions under conventional fertilization to identify effective spraying concentrations. In 2024, the same two concentrations were evaluated under conventional fertilization and 15%, 30%, and 45% fertilizer reductions. In the 2023 concentration screening trial under conventional fertilization, the enzyme complex increased kernels per ear by 5.6–9.7% and tended to increase the yield by 0.4–17.2% (not significant). In 2024, under reduced fertilization, enzyme application combined with 30% fertilizer reduction produced a stable yield response. In particular, the 300-fold dilution combined with 30% fertilizer reduction increased kernels per ear by 18.1% and 13.2% and grain yield by 16.9% and 9.5% in Fuyuan2 and Heyu 236, respectively. Soil analyses showed that the enzyme treatment mainly improved nutrient availability, as reflected by higher available P, available K, alkali-hydrolyzable N, organic matter, and available Cu, Zn, Fe, and Mn in the soil. These findings suggest that the harpin protein-based enzyme complex helped maintain maize yield under moderate fertilizer reduction by improving kernel formation and soil nutrient availability. Among the tested treatments, foliar application at 300-fold dilution combined with 30% fertilizer reduction showed the greatest potential for reducing fertilizer input while sustaining maize productivity. Full article

Maize (Zea mays L.), a typical thermophilic crop originating from tropical regions, exhibits an inherent sensitivity to low-temperature stress. Cold stress severely restricts maize seed germination, seedling growth, the physiological metabolism, and the final grain yield, which greatly limits its geographical cultivation range and sustainable industrial development. Elucidating the molecular regulatory mechanisms underlying maize cold tolerance and excavating cold-resistant functional genes are essential for the molecular breeding of cold-tolerant maize varieties and expanding maize planting areas in high-latitude and low-temperature-prone regions. In this study, using the strongly cold-tolerant maize inbred line B144 as the experimental material, we cloned the ZmMAPKKKA gene (NCBI accession: LOC103651289) and systematically screened and verified its cold-stress-specific interacting proteins via multiple molecular biological assays. The full-length coding sequence (CDS) of ZmMAPKKKA is 1134 bp, encoding a 377-amino-acid protein with a predicted molecular weight of 40.37 kDa. The quantitative real-time PCR (qRT-PCR) results demonstrated that the ZmMAPKKKA expression was significantly upregulated by 16.56-fold in maize roots after 12 h of low-temperature treatment, indicating a tissue-specific and robust cold response in root tissues. A total of 25 interacting proteins were identified through yeast two-hybrid screening, among which three stress-responsive proteins, including a protein kinase (LOC100286253), a protein phosphatase 2C (PP2C) (LOC542176), and a NAC transcription factor (LOC118474710), were selected for subsequent verification. The Pull-Down, Co-immunoprecipitation (Co-IP), and bimolecular fluorescence complementation (BiFC) assays consistently confirmed that ZmMAPKKKA specifically interacts with these three proteins both in vitro and in vivo under cold stress conditions. This study is the first to construct a ZmMAPKKKA-centered protein interaction module in the maize mitogen-activated protein kinase (MAPK) cascade under cold stress, establishing a novel kinase–phosphatase–transcription factor regulatory cascade that improves the current understanding of cold signal transduction mechanisms in maize. Homologous genes of ZmMAPKKKA in gramineous crops including rice (Oryza sativa) and sorghum (Sorghum bicolor) have been proven to participate in diverse abiotic stress responses, suggesting the conserved functional roles of MAPKKK family genes across gramineous species. Collectively, our findings provide comprehensive insights into the molecular mechanism of the maize MAPK signaling pathway mediating cold stress adaptation and supply valuable functional gene resources for cold-tolerant maize germplasm innovation and molecular breeding. Full article

Accurate and real-time detection of maize foliar diseases is important for field disease monitoring and yield protection. However, in complex natural field environments, different diseases often exhibit high visual similarity, and early weak lesions are easily confused with background elements such as dry leaves, soil, and shadows, leading to false positives and missed detections in existing models. To address these challenges, this study proposes an improved lightweight maize foliar disease detection model based on YOLO11, termed CKM-YOLO11. First, a mixed local channel attention mechanism is introduced and adapted to the task in the backbone to construct the C3k2-MLCA module, thereby enhancing joint modeling of local lesion textures, edge details, and global contextual information. Second, a lightweight residual attention module, named MLCA-HeadLite, is designed at the P5 layer of the neck/head to alleviate the suppression of weak lesion responses during deep feature fusion. Experimental results demonstrate that the proposed model achieves an mAP@50 of 81.5% on a self-constructed maize disease dataset with complex field backgrounds, improving mAP@50 and mAP@50–95 by 3.2 and 3.4 percentage points, respectively, compared with the baseline YOLO11, while maintaining a low parameter count and computational cost. Further analyses based on the confusion matrix, comparisons of detection results, and Grad-CAM visualizations indicate that the proposed model performs better in background suppression, retention of weak lesion responses, and robustness in complex scenes. This study provides a reference for the lightweight design of maize foliar disease detection models in complex field environments and their deployment on agricultural edge devices. Full article

Salt stress represents a significant abiotic stress factor that adversely affects plant growth and development. It directly inhibits both vegetative and reproductive growth, resulting in substantial reductions in crop yield and quality. Consequently, the identification of salt tolerance genes and the elucidation of their underlying molecular mechanisms are crucial for improving crop salt tolerance and ensuring agricultural productivity. To investigate the molecular basis underlying differential salt tolerance between Zheng58 and PH4CV, we employed pooled sequencing (BSA-seq) using extreme phenotypic individuals from their F₂ population and conducted a comparative transcriptome analysis at the seedling stage of the two genotypes. Phenotypic, physiological, biochemical, and ion content analyses revealed that Zheng58 exhibited significantly superior performance compared to PH4CV under salt stress conditions. BSA-seq analysis identified six genomic regions associated with salt tolerance, encompassing a total of 391 genes. Functional annotation enabled the screening of 151 candidate genes potentially involved in salt stress responses. Transcriptome profiling indicated that differentially expressed genes were significantly enriched in biological processes, particularly plant hormone signal transduction and MAPK signaling pathways. Integrating BSA-seq and transcriptome data, key candidate gene ZmACC2 (Zm00001eb419400) was identified as potentially involved in the regulation of salt tolerance in maize. This gene may modulate Na⁺/K⁺/Ca²⁺ homeostasis and reactive oxygen species metabolism through defense responses mediated by ethylene (ETH) and hydrogen peroxide, as well as through ion homeostasis regulatory pathways. This study provides valuable candidate genes and a theoretical foundation for further dissection of the molecular mechanisms governing salt tolerance in maize. Full article

Adequate fertilization with nitrogen (N) and potassium (K) is essential to sustain crop productivity and minimize nitrogen losses to the environment. However, the increasing imbalance in fertilizer use in Poland, with low potassium inputs, may impair long-term soil fertility and nitrogen use efficiency. The aim of this study was to evaluate the effects of long-term potassium omission on maize productivity and nitrogen use efficiency under varying nitrogen fertilization rates. A 16-year field experiment (2003–2018) was conducted in two different regions of Poland (Grabów and Baborówko), on soils with medium to low available potassium content. Maize response to potassium fertilization cessation was evaluated at increasing nitrogen rates (50–250 kg N ha⁻¹). Grain yield, nitrogen uptake (Yn), nitrogen surplus (Ns), and nitrogen use efficiency (NUE) were assessed according to the EU Nitrogen Expert Panel (EUNEP) approach. Potassium omission had little effect on maize yield and NUE indices. At nitrogen rates commonly applied in agricultural practice in Poland (~100 kg N ha⁻¹), NUE strongly exceeded 100%. The other NUE indices—nitrogen surplus and nitrogen uptake remained optimal (<80 kg N ha⁻¹, and >80 kg N ha⁻¹, respectively), regardless of potassium treatment. These results indicate a low risk of nitrogen losses under moderate nitrogen inputs, even without potassium fertilization. However, given the declining NUE trend on soils with low potassium content, a reduction in nitrogen use efficiency can be expected, particularly under high nitrogen application rates and continued unbalanced potassium fertilization. Full article

Nitrogen is an essential element for plant growth, and low nitrogen stress significantly restricts crop yield. Therefore, cultivating crop varieties that are tolerant to low nitrogen is crucial for agricultural production. The AT-hook motif nuclear localization protein (AHL) family is vital for plant stress resistance. To investigate the potential regulatory mechanisms of the AHL family in maize under low nitrogen stress, 35 ZmAHL genes were identified from the maize genome using bioinformatics methods. The results indicated that these genes encode proteins with lengths ranging from 203 to 573 amino acids, with relative molecular weights between 20.68 and 59.68 kDa, and they are unevenly distributed across 10 chromosomes. Most proteins encoded by these genes are alkaline hydrophilic proteins, primarily localized in the nucleus. Family expansion occurred through tandem and fragment repeats, which exhibited evolutionary conservation with rice homologous genes. Transcriptome analysis revealed that the majority of ZmAHL genes in drought-tolerant maize inbred lines were significantly up-regulated under drought and low nitrogen stress, with the ZmAHL10 gene displaying the most pronounced response to low nitrogen conditions. Experiments involving transgenic Arabidopsis thaliana further confirmed that the growth status, nitrogen uptake, and photosynthetic pigment content of ZmAHL10 overexpression strains under low nitrogen conditions were superior to those of the wild type, while the mutant exhibited significant growth inhibition. Overall, this study delineated the fundamental characteristics of the maize ZmAHL gene family and established that ZmAHL10 enhances low nitrogen tolerance in plants by improving nitrogen absorption capacity and maintaining the stability of the photosynthetic system. This research provides candidate genes and a theoretical foundation for the molecular breeding of maize with enhanced low nitrogen tolerance. Full article

To elucidate the regulatory mechanisms underlying the interaction between straw return and nitrogen (N) fertilization on yield formation, nutrient uptake, and soil N cycling in a continuous maize cropping system, a two-year positioning experiment was conducted. The study established two straw treatments (S0: 0 g/box; S1: 84 g/box) combined with three N levels (N0: 0 g/box; N1: 1.24 g/box; N2: 2.47 g/box). (The box refers to the cylinder used for planting maize.) The responses of maize yield, plant nutrient accumulation and partitioning, fertilizer-derived N ratio, nitrogen fertilizer use efficiency (NUE), and soil microenvironment were analyzed. Results indicated that under N1 conditions, straw return had a negligible effect on crop growth and yield formation. Conversely, under N2 conditions, straw return significantly enhanced maize yield and promoted the accumulation of N, phosphorus (P), and potassium (K) in plant tissues. ¹⁵N isotope tracing revealed a novel mechanism: rather than significantly altering direct fertilizer nitrogen use efficiency, straw return improved crop yield primarily by elevating indigenous soil N content and boosting the activities of N-transforming enzymes, thereby beneficially altering the ultimate environmental fate of the fertilizer N. Furthermore, straw return significantly boosted the activities of enzymes involved in N transformation and optimized the soil microenvironment. Collectively, straw return coupled with increased N application (specifically the S1N2 treatment) significantly maximizes maize yield, providing a theoretical basis for rational straw utilization and N management. Full article

With global warming, high-temperature stress has become a primary abiotic factor limiting maize yield and quality. Exposure to heat stress induces sunscald on maize leaves, which severely impairs photosynthesis and ultimately leads to yield reduction. In this study, we used the heat-tolerant inbred line Zheng58 and the heat-sensitive inbred line HSBN, both of which are cultivated maize (Zea mays L. subsp. mays) inbred lines, as parents to construct F₂ and F_2:3 populations consisting of 257 lines. Phenotyping for sunscald at the flowering stage was performed across three field environments. The F₂ population was genotyped using the Maize 10K SNP array to construct a genetic map containing 1728 single nucleotide polymorphism (SNP) markers. The map spanned 1406.22 cM, with an average marker density of 0.81 cM per marker. Eight quantitative trait loci (QTLs) associated with heat tolerance were identified in the F₂/F_2:3 populations, distributed on chromosomes 1, 4, 5, and 8, collectively explaining 3.43% to 35.44% of the phenotypic variation. Among them, the stable QTL qHT1-2 on chromosome 1 was consistently detected across all three environments, explaining 11.41% to 35.44% of the phenotypic variation. Additionally, a major QTL, qHT1-3, was identified on the same chromosome, accounting for 33.70% of the phenotypic variation. Transcriptome analysis of flowering-stage leaves from both parents revealed 9262 differentially expressed genes (DEGs). Of these, 21 DEGs were co-localized within the eight QTL intervals. The genes Zm00001eb013260, Zm00001eb012720, Zm00001eb013600, and Zm00001eb013100 exhibited highly significant differential expression between the parental lines, these four genes are identified as candidate genes in response to heat stress in maize, and their specific biological functions require further functional validation. Full article

Northern corn leaf blight (NCLB), caused by the fungal pathogen Setosphaeria turcica, is a devastating foliar disease that significantly threatens maize production in China. Previous studies have demonstrated that SET domain gene 102 (SDG 102), a gene encoding an H3K36 methyltransferase, plays a crucial role in regulating maize growth, development, and stress responses. This study used the wild-type (WT), SDG102 overexpression line (OE), and silencing line (SL) of the corn inbred line B73 as materials. After artificial inoculation with S. turcica, the phenotypic characteristics, disease index, yield, and other related traits of different strains were compared, and RNA-Seq was used to analyze the changes in the gene expression profile. The results showed that overexpression of SDG102 significantly inhibited pathogen spore germination and hyphal growth and enhanced the activity of antioxidant enzymes and the ability to scavenge reactive oxygen species in plants prior to S. turcica infection, the opposite trend was observed in SDG102 silencing lines. Compared with the wild-type, 1546 and 1837 differentially expressed genes (DEGs) responsive to S. turcica were identified in OE and SL, respectively. These differentially expressed genes primarily function in pathways such as plant–pathogen interactions, plant hormone signaling, and secondary metabolite biosynthesis. In the OE lines, genes related to plant–pathogen interactions, reactive oxygen species (ROS) production, and key phenylpropanoid biosynthesis genes exhibited higher expression levels. Furthermore, SDG102 regulates the synthesis of auxin (JA) and abscisic acid (SA) as well as the transcription of their signaling pathway genes, thereby influencing maize resistance to large leaf spot disease. Under corn leaf blight conditions, SDG102 overexpression increased yield by 9.29% compared to WT, while SL reduced yield by 10.10%. In conclusion, SDG102 enhances maize resistance to NCLB by positively regulating the expression of disease resistance genes, antioxidant enzyme activity, and hormone-mediated defense pathways. Full article

Effective spatial arrangement in maize population can reduce inter-plant competition, promote root development, and enhance nutrient uptake. This study aimed to clarify how planting density and row spacing affect maize growth and yield. A four-year field experiment (2011–2014) was conducted using three planting densities (50,025, 67,500, and 100,050 plants ha⁻¹) combined with two row spacings. Grain yield increased with higher planting density, whereas plant dry weight and nutrient (N, P, K) contents declined. Higher density restricted root growth both vertically and horizontally, particularly in the 0–10 cm soil layer and inner root zone. Narrower row spacing increased grain yield, plant dry weight, and shoot nutrient contents and improved vertical and inner-zone root growth while reducing growth in the outer root zone. At the highest density, these effects were most pronounced in fine roots (<2 mm diameter), with significant increases in root length and surface area in the 0–10 cm layer in both vertical and inner horizontal zones. Overall, higher density intensified root competition and inhibited root development, whereas narrower row spacing alleviated such competition, enhanced nutrient acquisition, and improved crop yield. These results highlight the central role of fine roots in mediating maize responses to planting density and row spacing, suggesting that a moderate planting density (~67,500 plants ha⁻¹) combined with narrower row spacing is optimal for balancing root development and yield. Full article

Northeast China is a key grain production region yet achieving coordinated improvements in maize yield and quality across diverse environments remains challenging. This study conducted a meta-analysis to evaluate maize yield and quality responses to chemical fertilizer inputs under varying natural (climate, soil) and anthropogenic (fertilization, planting) conditions. The results indicated that fertilizer application increased yield by 20.0%, and protein, fat, and starch contents by 12.6, 1.4, and 1.2%, respectively, compared to no fertilization. Yield response was highest under precipitation <450 mm and temperatures >7 °C, while protein and fat gains were favored by >600 mm precipitation and 5–7 °C temperatures. Soils with pH <6.5 and saline–alkaline properties supported greater yield gains, while brown and black soils promoted protein and fat accumulation, respectively. Moderate nutrient inputs (N 180–240, P₂O₅ 75–120, K₂O 90–135 kg ha⁻¹) outperformed lower or higher levels in improving both traits, with planting density also affecting response magnitude. Yield gains were primarily driven by soil fertility, whereas quality improvements were influenced by climate and management. Moderate fertilization facilitated the simultaneous enhancement of yield and quality. Tailored nutrient strategies based on soil and climate conditions can support regional maize productivity and contribute to food security. Full article

Maize (corn) (Zea mays L.) yield is influenced by complex factors, including abiotic and biotic stress and inconsistent nutrient use efficiency, which challenge optimal yield. Standard management recommendations often fall short, prompting interest in intensive management strategies within an Adaptive Maize Management System (ACMS). To investigate this, we employed an addition/omission technique within a randomized complete block design (RCBD) to compare standard maize management recommendations with an intensive management protocol aimed at identifying yield-limiting factors. Our intensive management approach combined early-season biostimulant applications with mid-season supplementation of phosphorus (P), potassium (K), and nitrogen (N) at the V7 stage, followed by foliar fungicides and additional foliar N at the R1 stage. Field trials spanned five Virginia locations over 2022 and 2023 under both irrigated and non-irrigated conditions, yielding ten site-years of data. Analysis via ANOVA in JMP^® Version 18 with Dunnett’s test revealed that the intensive management approach significantly increased grain yield in 3 of 10 experiments. Under non-irrigated conditions, the intensive management practices averaged 5.9% higher yield than the standard management check. We observed a higher response to irrigation in standard management check (34%) than in intensive management check (8.9%). Site-specific irrigation impacts ranged from 14% to 61%. Results emphasize site-specific input recommendations for yield enhancement. Full article

Maintaining the long-term viability of a wheat–maize planting system, particularly the synchronous improvement of crop production and soil organic carbon (SOC) sequestration, is crucial for ensuring food security in the North China Plain. A field experiment in which wheat–maize was regarded as an integral fertilization unit was carried out in Shanxi Province, China, adopting a split-plot design with different distribution ratios of phosphorus (P) and potassium (K) fertilizer between wheat and maize seasons in the main plot (A) (a ratio of 3:0, A1; a ratio of 2:1, A2) and different application rates of pure nitrogen (N) during the entire wheat and maize growth period (B) (450 kg·ha⁻¹, B1; 600 kg·ha⁻¹, B2). Moreover, no fertilization was used in the entire wheat and maize growth period for the control (CK). The findings showed that A2B1 treatment led to the highest response, with an average wheat yield of 7.75 t·ha⁻¹ and an average maize yield of 8.40 t·ha⁻¹ over the last 9 years. The highest SOC content (15.13 g·kg⁻¹), storage (34.20 t·ha⁻¹), and sequestration (7.11 t·ha⁻¹) were also observed under the A2B1 treatment. Both enhanced crop yield and SOC sequestration resulted from improvements in cumulative carbon (C) input, soil nutrients, and stoichiometry under the A2B1 treatment. It was confirmed that total N (TN), alkali-hydrolysable N (AN), available P (AP), available K (AK), and the ratios of C:K, N:K, and N:P had positive effects on crop yield through the labile components of SOC and on SOC sequestration through microbial necromass C. To conclude, our findings highlight the urgent need to optimize fertilizer management strategies to improve crop production and SOC sequestration in the North China Plain. Full article

Organic soil amendments, such as composts, mitigate the negative impacts on the environment that are caused by poor waste management practices. However, in the sub-Saharan African region, and Malawi in particular, studies investigating the agronomical efficacy and their ability to ameliorate drought stress when used as a soil amendment are minimal. This study aimed to evaluate the efficacy of sewage sludge and municipal solid waste (MSW) co-compost to ameliorate drought stress and improve crop productivity. Three experiments were conducted (i) to determine optimal application rate for co-compost, (ii) to evaluate yield response of maize and lettuce to co-compost application under contrasting soils, and (iii) to assess the effect of co-compost under water-limited conditions. Our results indicate that an application rate of 350 g co-compost per station was the most effective. This rate is 50% and 37% lower than the currently recommended rate for applying conventional compost to green vegetables and maize, respectively. In addition, under drought conditions, the co-compost application enhanced growth in lettuce, with less wilting, increased biomass and yield, approximately 130% greater leaf yield, and a 138% improvement in root growth. Furthermore, the relative root mass ratio (RRMR) was enhanced with the co-compost application by 103% under drought stress. This suggests that the co-compost amendment resulted in a greater allocation of biomass to the roots, which is a crucial morphological attribute for adapting to drought conditions. The concentration of K in the leaves and roots of plants treated with co-compost was significantly increased by 44% and 61%, respectively, under drought conditions, which may have contributed to osmotic adjustment, resulting in a significant increase in leaf relative water content (RWC) by a magnitude of 11 times. Therefore, in light of the rising inorganic fertilizer costs and the limited availability of water resources, these results demonstrate the potential of MSW and sludge co-composting in ameliorating the drastic effects of water- and nutrient-deficient conditions and optimizing growth and yield under these constraining environments. Full article

Balanced fertilizer application is crucial for achieving high-yield, high-quality, and efficient maize cultivation. Sulfur (S), considered a secondary nutrient, ranks as the fourth most essential plant nutrient after nitrogen (N), phosphorus (P), and potassium (K). S deficiency could significantly influence maize growth and development. Field experiments were conducted in Jiangsu, Yangzhou, China, from April 1 to July 20 in 2023. Jingkenuo2000 (JKN2000) and Suyunuo5 (SYN5) were used as experiment materials, and four treatments were set: no fertilizer application (F₀), S fertilizer application (F₁), conventional fertilization method (F₂), and conventional fertilization method with additional S application (F₃). The objective was to investigate the impact of S application on grain weight and the quality of fresh waxy maize flour and starch. The results indicated that all fertilization treatments significantly increased grain weight and the starch and protein contents in grains compared to no fertilization. Among these, F₃ exhibited the most significant increases. Specifically, in JKN2000, the grain weight, starch content (SC), and protein content (PC) increased by 27.7%, 4.8%, and 14.8%, respectively, while in SYN5, these parameters increased by 26.3%, 6.2%, and 7.4%, respectively, followed by F₂ and F₁. Compared to F₀, F₃ increased starch and protein contents by 4.8% and 14.8% in JKN2000, and by 6.2% and 7.4% in SYN5. Compared to F₀, F₂ and F₃ significantly increased the iodine binding capacity (IBC) of SYN5, with F₃ being more effective than F₂, while they had no significant effect on the IBC of JKN2000. The peak viscosity (PV) and breakdown viscosity (BD) of waxy maize flour and starch for both varieties showed a consistent response (increasing trend) to S application, and F₃ had the largest increase. Regarding the thermal properties of waxy maize flour, F₃ significantly enhanced the retrogradation enthalpy (ΔH_gel) of both varieties compared to F₀, while achieving the lowest retrogradation percentage (%R). In starch, the highest ΔH_gel and the lowest %R were observed under the F₂ treatment. In summary, under the conditions of this experiment, adding S fertilizer to conventional fertilization not only increased the grain weight of waxy maize but also effectively optimized the pasting and thermal properties of waxy maize flour and starch. Full article