Maize Research Articles

EVALUATION OF AN ANTI-DANDRUFF SHAMPOO INCORPORATING ETHANOL EXTRACT FROM CORN SILK (ZEA MAYS L.) AGAINST CANDIDA ALBICANS FUNGUS: FORMULATION AND ACTIVITY ASSESSMENT

Objective: The aim of this study was to investigate the effectiveness of corn silk (Zea mays L.) extract as an antifungal ingredient in shampoo formulation for treating dandruff caused by Candida albicans. Methods: Plant identification, sampling, preparation of simplisia, phytochemical screening, simplisia characterization, ethanol extraction of corn silk, and the formulation of shampoos with extract concentrations of 5%, 10%, and 15%, alongside blank and positive controls. The formulations underwent physical evaluation, irritation testing, and antifungal activity testing using the disc diffusion method. Results: The corn silk shampoo formulations were stable during storage, non-irritating, was in thick liquid form with yellowish to brown colour, corn scent, had pH between 5.0-5.8, foaming capacity at 10.3-13.0 cm, with the viscocity ranging 1967-2224 cPs, means it met the required standards for shampoo formulation and characterization. Antifungal testing revealed inhibition zone diameters of 0 mm for the blank (F0), 7.87 mm for F1 (5%), 9.46 mm for F2 (10%), 15.89 mm for F3 (15%), and 18.71 mm for the positive control (C+), with a one-way ANOVA test indicating a significant difference compared to the negative control. Conclusion: Corn silk extract could be effectively formulated into an antifungal shampoo, with the 15% concentration being the most effective against Candida albicans, highlighting its potential as a natural ingredient for anti-dandruff shampoos.

Comparative transcriptome analysis of maize (Zea mays L.) seedlings in response to copper stress.

Copper (Cu) is considered one of the major heavy metal pollutants in agriculture, leading to reductions in crop yield. To reveal the molecular mechanisms of resistance to copper stress in maize (Zea mays L.) seedlings, transcriptome analysis was conducted on the hybrid variety Zhengdan 958 exposed to 0 (control), 5, and 10 mM Cu stress using RNA-seq. In total, 619, 2,685, and 1,790 differentially expressed genes (DEGs) were identified compared to 5 mM versus 0 mM Cu, 10 mM versus 0 mM Cu, and 10 mM versus 5 mM Cu, respectively. Functional categorization of DEGs according to Gene Ontology revealed that heme binding, defense response, and multiorganism processes were significantly enriched under copper stress. Additionally, Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggested that the copper stress response is mediated by pathways involving phenylpropanoid biosynthesis, flavonoid biosynthesis, and glutathione metabolism, among others. The transcriptome data demonstrated that metabolite biosynthesis and glutathione metabolism play key roles in the response of maize seedlings to copper stress, and these findings provide valuable information for enhancing copper resistance in maize.

Gapless assembly of complete human and plant chromosomes using only nanopore sequencing.

The combination of ultra-long (UL) Oxford Nanopore Technologies (ONT) sequencing reads with long, accurate Pacific Bioscience (PacBio) High Fidelity (HiFi) reads has enabled the completion of a human genome and spurred similar efforts to complete the genomes of many other species. However, this approach for complete, "telomere-to-telomere" genome assembly relies on multiple sequencing platforms, limiting its accessibility. ONT "Duplex" sequencing reads, where both strands of the DNA are read to improve quality, promise high per-base accuracy. To evaluate this new data type, we generated ONT Duplex data for three widely studied genomes: human HG002, Solanum lycopersicum Heinz 1706 (tomato), and Zea mays B73 (maize). For the diploid, heterozygous HG002 genome, we also used "Pore-C" chromatin contact mapping to completely phase the haplotypes. We found the accuracy of Duplex data to be similar to HiFi sequencing, but with read lengths tens of kilobases longer, and the Pore-C data to be compatible with existing diploid assembly algorithms. This combination of read length and accuracy enables the construction of a high-quality initial assembly, which can then be further resolved using the UL reads, and finally phased into chromosome-scale haplotypes with Pore-C. The resulting assemblies have a base accuracy exceeding 99.999% (Q50) and near-perfect continuity, with most chromosomes assembled as single contigs. We conclude that ONT sequencing is a viable alternative to HiFi sequencing for de novo genome assembly, and provides a multirun single-instrument solution for the reconstruction of complete genomes.

Assessment of genetic diversity and heterotic alignment of CIMMYT and IITA maize inbred lines adapted to sub‐Saharan Africa

AbstractDespite the breeding efforts by many institutions, maize (Zea mays L.) productivity in sub‐Saharan Africa is still low. A limited number of productive maize hybrids have been developed partly due to a lack of knowledge on the diversity and heterotic relationship of the germplasm, especially in public breeding programs. Understanding the extent of diversity, structure, and heterotic grouping of available maize germplasm originating from different breeding programs is important to enhance long‐term genetic gain in hybrid maize breeding programs by optimizing heterotic pools using modern breeding tools. Information about the genetic structure of the available germplasm could help breeders design effective breeding strategies to improve yield. This study was conducted to determine the genetic diversity, population structure, and heterotic alignment among 187 elite maize inbred lines from the IITA (International Institute of Tropical Agriculture) and CIMMYT (International Maize and Wheat Improvement Center) maize breeding programs. The inbred lines were genotyped with 9857 Diversity Array Technology sequencing based single nucleotide polymorphism markers. Hierarchical clustering revealed three major groups, with some subgroups consistent with the selection history, and pedigree of the inbred lines. Three broad groups were detected: two consisting of CIMMYT lines and a mixed group consisting of both CIMMYT and IITA inbred lines. The STRUCTURE analysis revealed six subpopulations (fixation index value = 0.58), which depicts a moderate genetic diversity among the materials. Population 2 comprises the highest number of genotypes (102) from both programs. More than 89% of the elite lines had homozygosity exceeding 95%, with the remaining lines requiring further inbreeding through repeated self‐pollination. There was inconsistency in the predetermined heterotic groups' alignment between CIMMYT and IITA elite inbred lines. Analysis of molecular variance revealed that 96% of the total variation was accounted for by differences within groups, with the remaining 4% representing the variation between groups. This suggests that the two programs can benefit from germplasm exchange for the improvement of maize productivity.

Evaluating corn, tall fescue and canola growth on sediments dredged from the Lorain Harbor

AbstractSoil degradation is a worldwide problem, causing the declining performance of many plant species. Recently, the application of sediments dredged from aquatic waterways has received attention for their potential as an organic amendment to revive degraded agricultural soils. In Ohio, dredged sediment research has largely focused on the success of corn (Zea mays) or soybean (Glycine max) following the application of dredged sediments from the Toledo Harbor, neglecting the potential for dredged sediments from the other eight harbors and waterways to change plant performance as well as failing to quantify benefits for other commonly grown crops in the region. In a greenhouse experiment, we applied dredged sediments from the Lorain Harbor to degraded agricultural soils across a variety of application ratios and quantified changes in germination, height over the growing season, final biomass, and yield for canola (Brassica napus), tall fescue KY 31 (Festuca arundinacea), and corn to better understand the potential for dredged sediments from this location to increase performance for a variety of regionally important plant species. Overall, plants grown on agricultural soils supplemented with dredged sediments from the Lorain Harbor consistently grew taller, faster, and were larger than the 100% dredged sediment treatments. Furthermore, both corn and tall fescue grown on agricultural soil supplemented with dredged sediments had greater yield compared to their counterparts grown on unamended agricultural soil. In whole, outcomes from this research contribute to a growing body of research that support the use of dredged sediments as a soil amendment for agricultural soils.

Influence of CuO nanoparticles on photosystem II structural stability and functional activity of corn (Zea mays L.) under drought stress

Photoinhibition and photooxidation of photosystem II (PSII) is one of the key damages caused by drought stress. The present study aimed to assess whether or not foliar application of copper oxide nanoparticles (CuO NPs) is effective in promoting PSII stability and activity in corn plants under drought stress. Three-week old plants of corn were subjected to drought stress and varying levels of CuO nano-particles (0, 25, 50, and 100 mM) of the rooting medium. In this study, the effects of foliar application of copper oxide nanoparticles were assessed on growth, plant water status, nutrient uptake and structural stability of photosystem II of drought stressed corn plants. Drought stress impeded overall growth of the corn plants by reducing leaf relative water content, water potential, chlorophyll a content, and accumulation of K+ in plant leaves and roots. Exogenous application of 25 mM CuO NPs significantly enhanced the growth of corn. Exogenous application of CuO NPs improved the dry biomass and length of roots of the corn plants under drought stress. Although the application of nano-particles did not change leaf photosynthetic pigments, relative water content, K+ accumulation, it enhanced the accumulation of K+ in roots. Drought stress did not affect the structural stability of PSII, but it reduced its activity (performance index, PIABS) due to changes in the reaction center density and the biochemical reaction efficiency or electron transport capability. Exogenous application of CuO NPs improved PIABS due to increase in active reaction center density and electron transport efficiency. However, 100 mM CuO NPs application caused PSII damage at the donor end and reduced active reaction center density in the corn plants under both normal and drought stress conditions. The present findings provide a baseline information that foliar application of CuO-nanoparticles in low concentrations can improve the growth of corn by improving accumulation of K+ and increasing PSII activity. Further research is required to explore its effect on cellular redox balance and activities of PSII and PSI, and optimum dose of CuO-nanoparticles for developing formulations for their commercial applications in farmers’ fields.

Optimizing Nitrogen Management in Maize (Zea mays L.) Using Urease and Nitrification Inhibitorss

ABSTRACT Nitrogen (N) is essential for plant growth, and in conventional agriculture, it is usually supplied through fertilization. However, N can be lost through various pathways, reducing its availability to plants and decreasing fertilizer efficiency. This study examined the effects of split urea application and fertilizers containing the nitrification inhibitor 3.4-dimethylpyrazole phosphate (DMPP) and the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT). The fertilizers with inhibitors were applied at both full (100%) and reduced (75%) levels of the standard rate. Conducted over two years, the field trial aimed to assess the capacity of these treatments to mitigate N loss and meet the N requirements of maize effectively. The results of the study revealed that NBPT maintained the required N levels in the soil by meeting the N requirement of maize. On the other hand, DMPP caused N losses due to increasing ammonium levels in the soil during early plant growth stages. NBPT provided the best results in terms of plant yield and N content, whereas DMPP showed lower performance in these parameters. Reduced NBPT doses increased N use efficiency but were less effective in terms of yield compared to full doses. According to the result of the economic analysis, split urea treatment gave better results compared to all treatments. In conclusion, NBPT increased both yield and N use efficiency by regulating N release.

BODIPY-mediated photosensitization approach to control maize (Zea mays) pathogenic fungus Fusarium verticillioides

BODIPY-mediated photosensitization approach to control maize (Zea mays) pathogenic fungus Fusarium verticillioides

Microbiological activity of typical chernozem in cultivation of agricultural crops using agrobiotechnology

The article presents the results of a study of the microbial cenosis of typical slightly eroded chernozem under crops of corn for grain and oats under conditions of the use of agrobiotechnologies, including the treatment of seeds, soil, plants and post-harvest residues with microbiological preparations based on Trichoderma and Lactobacillus, as well as the use of nitrogen fertilizers and lime against the background of surface incorporation by-products. The research was carried out on the territory of the Federal State Budgetary Institution “Kursk FATS” (Medvensky district, Kursky district, Panino village) in two fields. In 2022, in the first field (grain crop rotation) oats (Avena sativa L.) variety “Borets” (predecessor – buckwheat) were cultivated, in the second (grain crop rotation) – hybrid corn (Zea mays L.) variety “Delitop” ( predecessor – winter wheat). The soil of the experimental field is typical low-humus, slightly eroded, heavy loamy chernozem on carbonate loess-like loam. It was established that during the harvesting phase under corn and oats, regardless of the factors (microbiological preparations, nitrogen fertilizers and lime) of the experiment, the soil was characterized by an increase in the number of saprophytic microflora and micromycetes compared to the phase of crop germination. The introduction of microbiological preparations based on Trichoderma and Lactobacillus with nitrogen fertilizers and by-products contributed to an increase in soil biogenicity, which on average during the growing season exceeded the control by 43.9 and 57.2%, respectively, under corn and oats. The maximum number of microscopic fungi was noted with the combined use of Trichoplant, SK and Biogor-Zh with mineral nitrogen, but the soil under oats in terms of the content of fungal microflora was 8.9 thousand CFU/g soils exceeded their amount under corn crops. The highest value of the transformation coefficient of organic matter was observed when by-products were inoculated with microbiological preparations with lime, regardless of the culture and timing of determination (phases of germination and harvesting of crops).

Influence of Crop Residue Management on Maize Production Potential

Residue management at the farm level is essential for ensuring sustainable agricultural productivity. This field experiment, initiated in 2005, provides maize data from 2016 to 2018. This study evaluates the impact of crop residue management and fertilization on maize yield and yield components. Maize was grown in a crop rotation sequence consisting of field pea (Pisum sativum L.), durum wheat (Triticum durum Desf.), milk thistle (Silybum marianum (L.) Gaertn.), and maize (Zea mays L.). The measures studied include aboveground biomass removal (K), aboveground biomass incorporation (R), mineral fertilizer application (F), and their combination (RF). The results indicate that R and RF significantly improve yield parameters, such as kernel number per ear (KNE), thousand seed weight (TSW), stalk yield, and harvest index (HI), compared to control (K) or aboveground biomass incorporation alone (R). Grain yield varied across the years, with significant increases being observed for the fertilizer treatments, particularly when combined with straw or stalk incorporation. A nominal increase in grain yield of 1.43 t ha−1 for the F treatment and 1.86 t ha−1 for the RF treatment represents an increase of 39% to 51% compared to K and R. Strong positive correlations were observed between grain yield and several factors, including ears per hectare (0.61), KNE (0.94), TSW (0.61), and HI (0.85). These findings underscore the role of crop residue management and promoting sustainable crop production.

Assessment of cover crop adoption and impact on weed management in Wisconsin corn‐soybean cropping systems

AbstractThe evolution and widespread occurrence of herbicide‐resistant weeds pose a major challenge for farmers and crop consultants across North America, warranting integrated management strategies. The adoption of cover crops offer weed suppression and soil health benefits but adds management complexity. A survey, targeting farmers and crop consultants, was conducted during the spring of 2023 to evaluate current cover crop management practices and perceptions in Wisconsin cropping systems. The survey included 26 questions across five sections: respondent profile, cover crop adoption and experience, cover crop management ahead of soybean [Glycine max (L.) Merr.], cover crop management ahead of corn (Zea mays L.), and general benefits and challenges of cover crop adoption. Farmers and crop consultants represented most respondents, influencing a total of 29,500 and 557,000 ha, respectively. Waterhemp (Amaranthus tuberculatus [Moq.] J.D. Sauer) and giant ragweed (Ambrosia trifida L.) were identified as the most troublesome weeds. Over 90% of respondents use herbicides to terminate their cover crops, and 68% of respondents agree that cover crops improved overall weed control in their farms/clients’ farms to some extent [cereal rye (Secale cereale L.) as main cover crop species]. Additionally, results demonstrate a strong consensus (85%) on cover crops positively influencing water retention, with 98% agreement on their efficacy in reducing soil erosion. Results from this survey can help guide farmers, agronomists, researchers, and policymakers with cover crop adoption, management, policies, incentives, and future research and education needs in Wisconsin and beyond to support the development of more sustainable and efficient weed and crop management strategies.

Impact of the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff ) Sorokin on Spodoptera frugiperda (J.E Smith), an invasive maize pest in Chad

The invasion of agricultural plots by Spodoptera frugiperda (J.E Smith) constitutes a serious constraint to the sustainable maize production in Chad. Since then, farmers have unsuccessfully used available chemical insecticides to control this pest at that respect, the present study evaluated the bio-efficacy of two strains (Chinese and Senegalese) of Metarhizium anisopliae on the pest, both under laboratory and field conditions. Laboratory results showed that both strains were virulent against FAW resulting in a mortality of 90 ± 5.77% for the strain from Senegal and 75 ± 5.00% for that from China. In the field, significant differences were observed among the four treatments tested, namely the two M. anisopliae strains (2.5 kg/ha), the control and Emamectin benzoate (20g/ha) for both the infestation of maize plants and FAW densities (P <0.05). Meanwhile, maize grain yields were significantly the highest in plots treated with Emamectin benzoate followed by plots treated with either of the two strains of the fungus whose yields were statistically similar (df = 3; F = 27.13; P <0.0001). This biopesticide was more virulent under laboratory and field conditions and could be a promising biological control agent against S. frugiperda as an alternative to synthetic insecticides. However, additional studies that evaluate the implementation cost of the microbiological control are very necessary for more objective and robust conclusions. Key words: Fall armyworm, microbiological control, Zea mays, Emamectin benzoate, biopesticides.

The ZmCPK39-ZmDi19-ZmPR10 immune module regulates quantitative resistance to multiple foliar diseases in maize.

Gray leaf spot, northern leaf blight and southern leaf blight are three of the most destructive foliar diseases affecting maize (Zea mays L.). Here we identified a gene, ZmCPK39, that encodes a calcium-dependent protein kinase and negatively regulates quantitative resistance to these three diseases. The ZmCPK39 allele in the resistant line displayed significantly lower pathogen-induced gene expression than that in the susceptible line. A marked decrease in ZmCPK39 abundance mitigated the phosphorylation and degradation of the transcription factor ZmDi19. This led to elevated expression of ZmPR10, a gene known to encode an antimicrobial protein, thereby enhancing maize resistance to foliar diseases. Moreover, the F1 hybrid with reduced ZmCPK39 expression favored disease resistance, thereby increasing yield. Hence, the discovery of the ZmCPK39-ZmDi19-ZmPR10 immune module provides insight into the mechanisms underlying broad-spectrum quantitative disease resistance and also offers a new avenue for the genetic control of maize foliar diseases.

The LTAR Cropland Common Experiment at Lower Chesapeake Bay.

The Lower Chesapeake Bay (LCB) Long-Term Agroecosystem Research (LTAR) Common Experiment (CE) located in Beltsville, MD, focuses on research of concern to producers of the major regional crops, which are corn (Zea mays L.), soybean [Glycine max (L.) Merr.], wheat (Triticum aestivum L.), and various forage species. Livestock production in the region includes broiler and laying chickens (Gallus gallus domesticus L.) and dairy and beef cattle (Bos taurus L.). The LCB region is among the most heavily populated in the United States. Urban development pressure is high for both farms and natural areas. The need to restore Chesapeake Bay water quality is a major influence on regional agricultural practices. Conservation practices such as cover cropping, no-till agriculture, and nutrient management planning are more common in the region compared to nationally. However, farmers still face management challenges implementing practices that address water quality and the rise of herbicide-resistant weeds. Researchers at the LCB site recognize the need to protect the Chesapeake and Delaware Bays and maintain farmer profitability. The LCB CE compares a 3-year crop rotation system featuring alternative crop management (cover crop intensification, crop rotation diversification, and integrated weed management [IWM]) with a prevailing 2-year system (no cover crops and no IWM), both under continuous no-tillage, to identify the optimal balance to promote the sustainability of regional cropping systems. The LTAR LCB site provides data-driven tools and solutions to support farmers in the mid-Atlantic region.

Saga of Soggy Sauerkraut

The creation of undesirable (soggy) sauerkraut resulted in the loss of $1,000,000 worth of organic sauerkraut in 2022, which prompted a multistep investigation of the cause and potential solution. The cause of this condition has been previously reported as unique fermentation conditions and the lack of key trace nutrients essential for cabbage (Brassica oleracea var. capitata) cell wall integrity. Because the condition was limited to organic sauerkraut in 2022, this investigation initially focused on differences in fermentation conditions between organic and conventional sauerkraut. No differences in fermentation conditions accounted for the condition; therefore, attention was focused on analyzing the mineral content of cabbage grown for sauerkraut production that pinpointed a deficiency in critical micronutrients such as iron, copper, manganese, boron, and zinc. This deficiency was traced to the use of poultry manure that was contaminated with glyphosate residue from conventionally fed turkeys and chickens that consumed genetically engineered (GE) feed and used as the fertilizer for organic cabbage production. The presence of glyphosate, a potent mineral chelator and antibiotic, was identified as a significant factor that impairs the absorption and physiological function of essential minerals in the shikimate metabolic pathway whereby cell walls and lignin are produced, thus compromising the structural quality of the sauerkraut. After this discovery, the study progressed to evaluate various remediation strategies aimed at eliminating glyphosate from the soil and restoring nutrient uptake. Corn grain and silage were selected as the test crops for this phase. Among the tested remediation solutions were raw sauerkraut juice containing Lactobacillus plantarum, which is reported to degrade glyphosate in the rumen of dairy cows and two patented proprietary microbial mixtures, PB027 and PB027SK, that degrade glyphosate by all three of the known metabolic pathways. These treatments were specifically formulated to degrade residual glyphosate in the soil. The results showed that these interventions could reduce soil glyphosate levels by 80% to 90% within 6 to 7 months to significantly enhance both the yield and quality of corn grain and silage. The increase in corn grain yield from glyphosate degradation on the Shiocton silt loam soil was 907.89 kg·ha−1 (13.5 bushels/acre). The increase in yield on the irrigated Kidder sandy loam soil was quantified at 726.31 kg·ha−1 (10.8 bushels/acre) for corn grain and 6.62 t·ha−1 (2.68 t/acre) for silage, with an additional improvement in silage feed quality beneficial for milk production. The findings underscore the importance of addressing both micronutrient sufficiency and glyphosate residue in soil to ensure the optimal growth of cabbage and the quality of sauerkraut produced. By successfully identifying manure as a subtle source of nutrient immobilization and implementing effective soil remediation techniques, this research highlights a clear path forward for improving crop yield and quality to ultimately enhance the structural integrity and consumer acceptance of sauerkraut. This study has broader applications for the nutritional content and crop yields of many organic crops that use conventional poultry and animal manures that may contain glyphosate in desiccated plant tissues or GE feeding operations.

Chitosan nanoparticles alleviate chromium toxicity by modulating metabolic homeostasis and promoting chromium sequestration in Zea mays L.

Chitosan nanoparticles (CSNPs) have been proposed as a potential alternative in alleviating chromium (Cr) toxicity. However, the mechanisms underlying remains poorly understood. This study investigates the effects of CSNPs on carbon/nitrogen metabolism, cell wall Cr binding capacity, and antioxidant activity in Zea mays L. under Cr stress. Cr stress decreased the total dry weight (DW) by 48.5 %. By contrast, the total DW was reduced by only 26.2 % in CSNPs-treated plants. Analysis of transcriptomic, enzyme activity, and metabolite content data, CSNPs-treated plants exhibited a higher level of relatively stable Carbon and Nitrogen metabolism than untreated plants. CSNPs application resulted in a substantial increase in the levels of sucrose and soluble protein by 78.0 % and 19.4 % in the leaves, and 60.0 % and 59.7 % in the roots, respectively. Meanwhile, CSNPs increased the contents of glutathione, phytochelatin, and cell wall polysaccharide. This increase resulted in a higher retention of Cr in vacuole and cell wall. Additionally, CSNPs alleviated the oxidative damage by improving antioxidant activity. Overall, our results suggest that CSNPs alleviates Cr toxicity by modulating metabolic homeostasis and promoting Cr sequestration in maize plants. This study provides new insights into the mechanisms underlying CSNPs-mediated Cr stress response with potential implications for crop production.

Soil Mulching Practices Increased Grain‐Filling Capacity of Rainfed Maize (Zea mays L.) by Improving Soil Hydrothermal Condition and Leaf Photosynthetic Potential

ABSTRACTGrain‐filling rate and duration largely affect the grain‐filling capacity, which determines the grain yield of maize (Zea mays L.). Nevertheless, there is little about the mechanism of how various soil mulching practices affect the leaf photosynthetic potential and subsequent grain‐filling capacity of maize. Field experiments were undertaken on rainfed summer maize in northwest China under flat cultivation without mulch (FNM), flat cultivation with straw mulch (FSM), flat cultivation with transparent film mulch (FTF), flat cultivation with black film mulch (FBF), ridge‐furrow cultivation with transparent film mulch (RTF) and ridge‐furrow cultivation with black film mulch (RBF) in 2021 and 2022. This study explored the impact of various soil mulching patterns on soil hydrothermal condition, leaf growth, photosynthetic potential, aboveground dry matter growth and grain‐filling process of rainfed maize. The dynamics of leaf area index (LAI) and grain‐filling were fitted with growth equations, and the relationships of grain‐filling rate, leaf area duration and LAI withering rate were quantified. The results showed that, compared with FNM, other five soil mulching practices improved soil hydrothermal condition, the maximum LAI and leaf expansion rate but reduced leaf withering rate, thereby increasing radiation interception rate (RI) at the grain‐filling stage. The soil mulching practices also increased leaf SPAD value, net photosynthetic rate, photosynthetic nitrogen use efficiency and the aboveground dry matter. Compared with FNM, other five practices extended the effective grain‐filling period and the active period of grain‐filling, increased the maximum and mean grain‐filling rates, improved the 100‐kernel weight and the average kernel per ear (KPE), thereby increasing grain yields by 9.2%, 33.7%, 38.0%, 46.3% and 58.6%, respectively. The functional relationships of grain‐filling rate and accumulated leaf area duration (y = a/(1 + b*exp(−kx))), and the functional relationships of grain‐filling rate and LAI withering rate (y = (a + cx + ex2)/(1 + bx + dx2)) were first proposed. In conclusion, various soil mulching practices improved the soil hydrothermal condition, green leaves growth process and RI, which improved the leaf photosynthetic potential and the grain‐filling capacity, thereby increasing the 100‐kernel weight, KPE and grain yield. This study can help us quantitatively describe and better understand the maize grain‐filling process under various mulching practices.

Effect of foliar fertilization of nano urea and 2% urea on yield, nutrient uptake, nitrogen use efficiency and economics of maize (Zea mays L.)

Effect of foliar fertilization of nano urea and 2% urea on yield, nutrient uptake, nitrogen use efficiency and economics of maize (Zea mays L.)

A rapid dispersal of maize from the Great Plains to northeastern North America

Northern Flint maize (Zea mays ssp. mays) is a distinct landrace that was common throughout early historical northeastern North America. It is likely represented archaeologically as Eastern 8-row maize, the dominant form there after 1200 CE. Genetic analyses indicate that Northern Flint is most likely derived from maize in the American Southwest. Evidence for maize in the form of phytoliths and starch recovered from directly radiocarbon dated cooking residues occurs in the Northeast by 290 BCE. Until recently there has been no substantiated evidence for maize of similar or older age in the Great Plains, through which maize is likely to have dispersed from the Southwest. A recent report of early microbotanical evidence for maize from the central Plains allows Bayesian modeling of radiocarbon dates to estimate the amount of time that elapsed before maize spread from the Plains to the Northeast. Results indicate only a short amount of time elapsed, from a few to less than 170 years.

Response of crop seed germination and primary root elongation to a binary mixture of diclofenac and naproxen.

Non-steroidal anti-inflammatory drugs, diclofenac (DCF) and naproxen (NPX), represent a group of environmental contaminants often detected in various water and soil samples. This work aimed to assess possible phytotoxic effects of DCF and NPX in concentrations 0.1, 1 and 10 mg/L, both individually and in binary mixtures, on the seed germination and primary root elongation of crops, monocots Allium porrum and Zea mays, and dicots Lactuca sativa and Pisum sativum. Results proved that the seed germination was affected by neither individual drugs nor their mixture. The response of primary root length in monocot and dicot species to the same treatment was different. The Inhibition index (%) comparing the root length of drug-treated plants to controls proved to be approximately 10% inhibition in the case of dicots lettuce and pea, and nearly 20% inhibition in monocot leek, but almost 20% stimulation in monocot maize. Assessment of the binary mixture effect confirmed neither synergistic nor antagonistic interaction of DCF and NPX on early plant development in the applied concentration range.