Maize Kernels Research Articles

CORN GRINDING MACHINE MANUFACTURING USES ELECTRIC POWER AND HUMAN POWER

The issue with maize is that kernel size is frequently not the same as grain size if you want the grains or seeds to be fine. Building a basic corn-grinding machine with electricity and human power in case of an electrical outage is the community service that was completed. The process begins with the design of a corn grinding machine, is followed by the construction of the machine and testing, specifically grinding performance tests for different capacities of 3 kg, 4 kg, and 5 kg of corn utilizing both electric and manual power. The findings of a 60-minute human-powered corn grinding machine performance test showed that the maximum ground corn grinding was fine, weighing 20 kg of ground corn with a fairly excellent grinding of corn granules/seeds. In the meantime, 30 kg of corn were weighed during the electric corn grinder's performance test in 60 minutes, and the machine's grinding of maize grains and ores was reasonably successful. Keywords: Maize kernels or seeds; corn grinder; machine performance evaluation; labor-intensive Human power; electricity power

Characterization of mycotoxins produced by two Fusarium species responsible for postharvest rot of banana fruit

AbstractIn an open-air market in southern Italy, we noticed ‘Lady finger’ banana fruit imported from Costa Rica showing a severe rot, whose symptoms consisted of necrotic peel lesions with variable shape and size. Fusarium sacchari and F. proliferatum were consistently isolated from symptomatic fruit. In pathogenicity tests on ‘Lady finger’ banana fruit, F. proliferatum was more virulent than F. sacchari. Quantitative Time-of-Flight Mass Spectrometric analysis of secondary metabolites produced by isolates of these two Fusarium species on three different matrices (banana peel, barley and maize kernels) identified 11 mycotoxins. Seven of them (Fusaproliferin, Fumonisins A1, Fumonisins A2 and Fumonisins B1, Hydrolysed Fumonisin B1, Fusarin C and Moniliformin) were detected in matrices contaminated by F. proliferatum isolates. Fumonisin A1 was the prevalent mycotoxin in both maize kernels and banana peel, while Fumonisin A2 prevailed in barley kernels. Similarly, seven mycotoxins (the cyclic hexadepsipeptides Enniatins B2, B3 and B4, Fumonisins A1 and B2, Hydrolysed Fumonisin B1 and Fusarin C) were detected in matrices contaminated by F. sacchari isolates, but they were only in part the same as those produced by F. proliferatum isolates. Fusarin C prevailed in all three matrices colonized by F. sacchari. Fumonisin A1 was detected exclusively in maize kernels while Enniatins B3 and B4, Fumonisin B2 and Hydrolysed Fumonisin B1 were detected exclusively in barley kernels. Overall, F. proliferatum produced a higher amount of mycotoxins than F. sacchari. Moreover, in banana peel both species produced a lower number and amount of mycotoxins than in the other two matrices.

Determination of the Best Performing Sri Lankan Maize Landraces Based on the Kernel Nutritional Composition

Maize (Zea mays L.) is one of the most widely cultivated cereal crops in the world as well as in Sri Lanka. Data on the nutritional composition of maize is beneficial for the food and feed industry, but there is a lack of information regarding this avenue in Sri Lanka. Therefore, this study aimed to investigate the suitable landraces with higher nutritional composition among the different landraces by evaluating nutritional parameters using the rank summation index. The maize kernels derived from 42 local landraces were used and the responses were with varieties Bhadra (Control) and Pacific. The proximate composition was analyzed using Near-infrared spectroscopy (NIR) and carbohydrate content and energy were determined using the calculation method. Subsequently, the data were analyzed by performing ANOVA and the rank summation index (RSI) to identify the best performer among the landraces. The results revealed that there were significant differences (p<0.05) among the nutritional components for moisture, ash, fiber, fat, protein, carbohydrates, and energy among the tested landraces. Accordingly, the maize landraces SEU 22, SEU 31, and SEU 2 were identified as the superior germplasms regarding nutritional composition compared with Bhadra, as they exhibited the lowest RSI of 85, 88, and 89, respectively. Therefore, these maize landraces were recommended for future breeding programs for the development of nutritionally enriched maize grains and for sustainable production where land limitation is a challenge.

A detection method of oil content for maize kernels based on CARS feature selection and deep sparse autoencoder feature extraction

To achieve accurate, rapid, and non-destructive oil content determination in maize, a neural fitting model that combines feature selection and feature extraction is proposed. Competitive adaptive re-weighted sampling (CARS) is used to choose features, while the deep sparse autoencoder (DSAE) network is utilized to extract features. The 160 spectral data from the near-infrared spectra public datasets of maize served as experimental samples. Several preprocessing approaches were tested, and the first-order derivatives fared the best. To capture the various degrees of abstract features in spectral data, SSAE networks with two or three hidden layers are developed. The number of nodes in the network's hidden layer (30, 50, 70, 100, 200, 300, respectively) and the network's sparsity parameter (0.001, 0.004, 0.007, 0.01, 0.04, 0.07, 0.1, 0.2, …, 1) are tuned to generate partial least squares regression (PLSR) models for testing the feature learning effect. The highest performance comes from a three-layer network with 200 hidden layer nodes and a sparsity parameter of 0.04. This network extracts three levels of features from the preprocessed spectral data: F1, F2, and F3. Full_cars, F1_cars, F2_cars, and F3_cars are obtained using the CARS algorithm for variable selection on the preprocessed spectral data, F1, F2, and F3, respectively. They are then integrated into a final feature set to build a neural-fitting network (FNN). After training and testing, the test set has a correlation coefficient of 0.964205 and an mean square error (MSE) of 0.00636809. Comparing this model to support vector machine regression (SVR), PLSR, and gaussian process regression (GPR), the findings demonstrate that the model described in this study outperforms the others in terms of fitting accuracy and generalization performance. To summarize, this paper introduces a new regression analysis method based on near-infrared spectra.

Resistance of Transgenic Maize Cultivars to Mycotoxin Production-Systematic Review and Meta-Analysis.

Approximately 25% of cereal grains present with contamination caused by fungi and the presence of mycotoxins that may cause severe adverse effects when consumed. Maize has been genetically engineered to present different traits, such as fungal or insect resistance and herbicide tolerance. This systematic review compared the observable quantities, via meta-analysis, of four mycotoxins (aflatoxins-AFL, fumonisins-FUM, deoxynivalenol-DON, zearalenone-ZEA) between genetically modified (GM) and conventional maize kernels. This study was conducted following the PRISMA guidelines, with searches performed using PubMed, Web of Science, Scopus, Google Scholar, and CAPES journals databases. Analyses were conducted using RevMan v.5.4 software. Transgenic maize showed a 58% reduction in total mycotoxins (p < 0.001) compared to conventional maize. FUM were the most impacted, with a 59% reduction (p < 0.001) in GM maize. AFL and ZEA levels were also lower in GM maize by 49% (p = 0.02) and 51% (p < 0.001), respectively. On the other hand, DON levels increased by 6% (p < 0.001) in GM maize compared to conventional maize. However, results for ZEA and DON were inconclusive due to the limited research and sample sizes. We conclude that transgenic maize reduces total mycotoxins by over 50%, primarily fumonisin and aflatoxin. Most studies presented maize varieties that were resistant to insects or herbicides, not fungal pathogens, showing a positive collateral effect of these genetic alterations. Therefore, transgenic maize appears to be a safer product for animal and human consumption from a toxicological point of view. Further studies with larger sample sizes are needed to confirm our findings for ZEA and DON in transgenic maize.

Factors influencing fumonisin B1 contamination in maize: insights from two production regions in Costa Rica.

Maize (Zea mays L.) is an important cereal crop worldwide. Contaminated maize kernels pose a significant mycotoxin exposure risk for humans in Latin America. Fumonisins, the most prevalent mycotoxin in maize, typically occur during pre-harvest conditions leading to significant economic losses. Various factors, including weather conditions, may influence this contamination. This study aimed to determine the association between fumonisin B1 (FB1) contamination, prevalence of Fusarium verticillioides, weather conditions and kernel quality in the two primary maize production areas in Costa Rica (Brunca and Chorotega). All maize samples (100%) showed FB1 contamination, with higher concentrations in samples from Brunca region, consistent with the presence of F. verticilliodes. Weather conditions appeared to play an important role in this contamination, since Brunca region had the highest mean temperature and relative humidity after maize silking (R1) and the total monthly rainfall in this region was significantly higher during the last two months of maize cultivation (grain-filling and physiological maturity stages R3 to R6). Interestingly, this study found a negative correlation between grain damage and kernel contamination with FB1 and F. verticillioides. The concentration of mineral nutrients in kernels from both regions was largely similar. Most nutrients in kernels exhibited a negative correlation with FB1, particularly nitrogen. Zinc and phosphorus were the only nutrients in kernels showing a positive correlation with FB1 in samples from the Brunca region. The results highlight elevated levels of FB1 contamination in maize and contribute to a better understanding of pre-harvest factors influencing FB1 contamination in tropical conditions.

Low molecular weight acids differentially impact Fusarium verticillioides transcription

Fusarium verticillioides is both an endophyte and pathogen of maize. During growth on maize, the fungus often synthesizes the mycotoxins fumonisins, which have been linked to a variety of diseases, including cancer in some animals. How F. verticillioides responds to other fungi, such as Fusarium proliferatum, Aspergillus flavus, Aspergillus niger, and Penicillium oxalicum, that coinfect maize, has potential to impact mycotoxin synthesis and disease. We hypothesize that low molecular weight acids produced by these fungi play a role in communication between the fungi in planta/nature. To address this hypothesis, we exposed 48-h maize kernel cultures of F. verticillioides to oxalic acid, citric acid, fusaric acid, or kojic acid and then compared transcriptomes after 30 min and 6 h. Transcription of some genes were affected by multiple chemicals and others were affected by only one chemical. The most significant positive response was observed after exposure to fusaric acid which resulted in >2-fold upregulation of 225 genes, including genes involved in fusaric acid synthesis. Exposure of cultures to the other three chemicals increased expression of only 3–15 genes. The predicted function and frequent co-localization of three sets of genes support a role in protecting the fungus from the chemical or a role in catabolism. These unique transcriptional responses support our hypothesis that these chemicals can act as signaling molecules. Studies with gene deletion mutants will further indicate if the initial transcriptional response to the chemicals benefit F. verticillioides.

Genome-wide association study of carotenoids in maize kernel.

In this study, the contents of four carotenoids in 244 maize inbred lines were detected and about three million single nucleotide polymorphisms (SNPs) for genome-wide association study to preliminarily analyze the genetic mechanism of maize kernel carotenoids. We identified 826 quantitative trait loci (QTLs) were significantly associated with carotenoids contents, and two key candidate genes Zm00001d029526 (CYP18) and Zm00001d023336 (wrky91) were obtained. In addition, we found a germplasm IL78 with higher carotenoids. The results of this study can provide a theoretical basis for screening genes that guide kernel carotenoids selection breeding.

Golden harvest: Nitrogen’s impact on maize carotenoids

Highly weathered tropical soils are deficient in nitrogen (N), phosphorus (P), and potassium (K), impacting maize yield and nutritional quality. The influence of soil N and P on maize carotenoid content remains poorly characterized, hindering nutritional advancements. This study examined how varying N fertilizer rates (0, 60, and 120 kg N/ha) affect provitamin A (proVA) carotenoid accumulation in different maize genotypes. proVA carotenoid components analyzed were alpha-carotene (αC), beta-carotene (βC), and beta-cryptoxanthin (βCr). The study also estimated proVA content among maize genotypes. The increasing N rates from 0 to 120 kg N/ha significantly (P < 0.05) enhanced proVA carotenoid content, as higher proVA content observed in higher N rates i.e., in 120 kg N/ha compared to low N rates (60 kg N/ha and 0 kg N/ha). The βC mean concentration ranged 0.42 to 13.08 µg/g, 0.56–11.17 µg/g and 0.38–11.99 µg/g for 120 kg N/ha, 60 kg N/ha, and 0 kg N/ha, respectively. While βCr concentration ranged 2.35 to 4.49 µg/g for 0 kg N/ha, 2.37–4.34 µg/g for 60 kg N/ha, and 2.35–4.69 µg/g for 120 kg N/ha. Whereas for αC content in studied maize genotypes ranged 0.38 to 13.08 µg/g and the highest value observed on high fertilizer rate (120 kg N/ha) where low content determined on low N rates (0 and 60 kg N/ha). The proVA ranged from 1.93 to 16.7 µg/g, the level of proVA in studied maize genotypes increased with increase in fertilizer rates. For instance, for 0 kg N/ha, proVA ranged from 2.03 to 12.3 µg/g), 60 kg N/ha (2.11–14.1 µg/g) and for 120 kg N/ha (1.99–16.7 µg/g). Genotype EE20 performed better in all the carotenoid components treated with 120 kg N/ha and the T4 had poor performance under no fertilizer plots. Indicating that N had a significant influence on proVA accumulation in maize kernels. The highest provitamin A concentration (16.7 µg/g) was observed on 120 kg N/ha, followed by 14.1 µg/g reported on 60 kg N/ha, and the lowest (12.3 µg/g) was observed on 0 kg N/ha. Thus, for enhancing carotenoid content in maize, N fertilization is crucial. This suggest that in low-N soils, biofortification of provA carotenoids efforts may not bring successful results.

Genome-wide association study of trace elements in maize kernels

Maize (Zea mays L.), a staple food and significant economic crop, is enriched with riboflavin, micronutrients and other compounds that are beneficial for human health. As emphasis on the nutritional quality of crops increases maize research has expanded to focus on both yield and quality. This study exploreed the genetic factors influencing micronutrient levels in maize kernels through a comprehensive genome-wide association study (GWAS). We utilized a diverse panel of 244 inbred maize lines and approximately 3 million single nucleotide polymorphisms (SNPs) to investigate the accumulation of essential and trace elements including cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), selenium (Se) and zinc (Zn). Our analysis identified 842 quantitative trait loci (QTLs), with 12 QTLs shared across multiple elements and pinpointed 524 potential genes within a 100 kb radius of these QTLs. Notably ZmHMA3 has emerged as a key candidate gene previously reported to influence the Cd accumulation. We highlighted ten pivotal genes associated with trace element transport including those encoding heavy metal ATPases, MYB transcription factors, ABC transporters and other crucial proteins involved in metal handling. Additionally, haplotype analysis revealed that eight inbred linesaccumulated relatively high levels of beneficial elements while harmful elements were minimized. These findings elucidate the genetic mechanisms underlying trace element accumulation in maize kernels and provide a foundation for the breeding of nutritionally enhanced maize varieties.

Biomass-derived carbon dots enhanced maize (Zea mays L.) drought tolerance by regulating phyllosphere microorganisms and ion fluxes

Enhancing crop drought tolerance is beneficial for increasing crop yield and ensuring food security. This study demonstrates that foliar application of biomass-derived carbon dots (Soy-CDs, 10 mg·L−1) can enhance the drought tolerance of maize, leading to an increase in fresh weight of maize shoots and roots (50.5 % and 54.9 %) and dry weight of maize shoots and roots (40.0 % and 37.7 %), respectively. Meanwhile, Soy-CDs altered the abundance of phyllosphere microorganisms (e.g. Proteobacteria, Deinococcus-Thermus, Verrucomicrobia, and Actinobacteria) of maize under drought stress, which enhanced the nitrogen fixation and stress resistance in maize leaves. Besides, Soy-CDs also promote Ca2+ influx and Na+ efflux in maize mesophyll cells under drought stress, facilitating the regulation of ion osmotic balance and contributing to the improvement of maize drought tolerance. Furthermore, Soy-CDs enhanced photosynthesis (55.3 %) of maize under drought stress, and the full life cycle study showed that Soy-CDs can promote the metabolism of maize kernels, ultimately improve the yield (40.5 %) and nutritional quality of maize. Therefore, this work discovers the enormous potential of biomass-derived carbon dots in improving drought resistance and quality of crop, which contributes to ensure food security.

Engineering high amylose and resistant starch in maize by CRISPR/Cas9-mediated editing of starch branching enzymes

To improve the amylose content (AC) and resistant starch content (RSC) of maize kernel starch, we employed the CRISPR/Cas9 system to create mutants of starch branching enzyme I (SBEI) and starch branching enzyme IIb (SBEIIb). A frameshift mutation in SBEI (E1, a nucleotide insertion in exon 6) led to plants with higher RSC (1.07%), lower hundred-kernel weight (HKW, 24.71 ± 0.14 g), and lower plant height (PH, 218.50 ± 9.42 cm) compared to the wild type (WT). Like the WT, E1 kernel starch had irregular, polygonal shapes with sharp edges. A frameshift mutation in SBEIIb (E2, a four-nucleotide deletion in exon 8) led to higher AC (53.48%) and higher RSC (26.93%) than that for the WT. E2 kernel starch was significantly different from the WT regarding granule morphology, chain length distribution pattern, X-ray diffraction pattern, and thermal characteristics; the starch granules were more irregular in shape and comprised typical B-type crystals. Mutating SBEI and SBEIIb (E12) had a synergistic effect on RSC, HKW, PH, starch properties, and starch biosynthesis-associated gene expression. SBEIIa, SS1, SSIIa, SSIIIa, and SSIIIb were upregulated in E12 endosperm compared to WT endosperm. This study lays the foundation for rapidly improving the starch properties of elite maize lines.

Mycotoxigenic fungal growth within stored maize (Zea mays L.) at different storage altitudes and durations

In this study, the interactive effect of maize (Zea mays L.) storage altitude, storage duration, and initial moisture content on the invasion of mycotoxigenic fungi on maize stored within woven polypropylene bags was evaluated. The direct plating method on potato dextrose agar media was used for the isolation of maize kernel fungi, and the identification was done morphologically. The study result revealed that Aspergillus spp., Fusarium spp., and Aspergillus flavus were identified at all storage altitudes (1500, 1800, and 2200 m above sea level (m.a.s.l.)), and the level of fungal growth was affected by storage duration and initial moisture content. There was a relatively higher density of Aspergillus flavus at lower altitudes. Aspergillus flavus growth was significantly increased by prolonging maize storage duration at 1500 m.a.s.l. altitude; kernel infection increased from 33% to 47% between the 4th and 8th months of storage. Similarly, there was a higher incidence of Aspergillus spp. at the lower altitude; after 8 months of storage, the relative density of Aspergillus spp. was 69% at 1500 m.a.s.l. altitude. After 8 months of storage, the highest kernel infection with Fusarium spp. (53%) was observed at 2200 m.a.s.l. (the highest altitude). There was a decrease in Fusarium spp. kernel infection from the 4th month (27%) to the 8th month (7%) at 1500 m.a.s.l. altitude. The relative density of the fungi increased with an increment in the initial storage moisture content of maize. Hence, the existence of Aspergillus spp., Aspergillus flavus, and Fusarium spp. in maize stored with different initial moisture contents (12%–15%), various sites of an agro-ecological zone, and storage durations emphasizes the need to utilize climate-smart post-harvest technologies for storing maize for more than 4 months in woven polypropylene bags, particularly at lower altitudes (1500 m.a.s.l.) to minimize aflatoxin contamination.

Maize grains treatments for total aflatoxin reduction for use as human food and livestock feed

Abstract Maize is prone to aflatoxin contamination prevailing in the high-risk regions in Kenya, where maize is rendered unfit for uses as food and feed. The objective of the study was to identify strategies that can be used to decontaminate aflatoxin in contaminated maize. Therefore, an experiment was conducted using maize from Kilifi contaminated with aflatoxin soaked in different solutions, done as single and combined treatments. Maize grains were used in portions of 250 g for the mitigation experiments and placed in conical flasks of 1 litre capacity and treatment application done. All the treatments were compared to the control with no treatment applied and set to 100%. The results revealed that, aflatoxin was reduced by 78.9% by soaking maize kernels in distilled water for 24 h under a single treatment. Soaking in aqueous ammonia for 24 h reduced aflatoxin by 68.1%. Soaking grains in sodium bisulphite for 24 h reduced by 59.3% and citric acid by 38.8%. The combination of sorting and aqueous ammonia was most effective with 90.8% aflatoxin reduction. The combination of sorting and sodium bisulphite lowered the levels to 72.9%, while citric acid and dehulling were 55.3% effective. Aflatoxin reduction methods to levels that are within the allowable limits of 10 μg/kg and 20 μg/kg will enable grains to be used as human food and livestock feed, respectively. Therefore, effective methods should be adopted by farmers to put maize to good use for human food and livestock feed instead of throwing away or using it with the high levels of aflatoxin.

Enhancing kernel oil and tailoring fatty acid composition by genomics-assisted selection for dgat1-2 and fatb genes in multi-nutrient-rich maize: new avenue for food, feed and bioenergy.

Enhancing maize kernel oil is vital for improving the bioavailability of fat-soluble vitamins. Here, we combined favourable alleles of dgat1-2 and fatb into parental lines of four multi-nutrient-rich maize hybrids (APTQH1, APTQH4, APTQH5 and APTQH7) using marker-assisted selection (MAS). Parental lines possessed favourable alleles of crtRB1, lcyE, vte4 and opaque2 genes. Gene-specific markers enabled successful foreground selection in BC1F1, BC2F1 and BC2F2, while background selection using genome-wide microsatellite markers (127-132) achieved 93% recurrent parent genome recovery. Resulting inbreds exhibited significantly higher oil (6.93%) and oleic acid (OA, 40.49%) and lower palmitic acid (PA, 14.23%) compared to original inbreds with elevated provitamin A (11.77 ppm), vitamin E (16.01 ppm), lysine (0.331%) and tryptophan (0.085%). Oil content significantly increased from 4.80% in original hybrids to 6.73% in reconstituted hybrids, making them high-oil maize hybrids. These hybrids displayed 35.70% increment in oil content and 51.56% increase in OA with 36.32% reduction in PA compared to original hybrids, while maintaining higher provitamin A (two-fold), vitamin E (nine-fold), lysine (two-fold) and tryptophan (two-fold) compared to normal hybrids. Lipid health indices showed improved atherogenicity, thrombogenicity, cholesterolaemic, oxidability, peroxidizability and nutritive values in MAS-derived genotypes over original versions. Besides, the MAS-derived inbreds and hybrids exhibited comparable grain yield and phenotypic characteristics to the original versions. The maize hybrids developed in the study possessed high-yielding ability with high kernel oil and OA, low PA, better fatty acid health and nutritional properties, higher multi-vitamins and balanced amino acids, which hold immense significance to address malnutrition and rising demand for oil sustainably in a fast-track manner.

Maize–fusarium interactions: Tunisian insights into mycotoxin ecology

Maize is a worldwide crop yet can be associated with mycotoxigenic fungi, much investigated in humid tropical and cooler, wet temperate regions. However, in hot, arid/semi-arid regions data on their occurrence are poor. In this paper, we focused on interactions between maize and Fusarium fungal species in Tunisia, which has a Mediterranean climate, with hot, dry summers and milder, damper winters. Maize kernels, stalks, and roots were sampled from 19 agricultural fields and 56, 72, and 88 % of samples, respectively, yielded Fusarium isolates. Based on molecular identifications, these were mainly F. verticillioides (67 %), and other species of Fusarium fujikuroi species complex and members of Fusarium incarnatum-equiseti-, oxysporum-, burgessii-, solani- and concolor species complexes. In addition, five isolates were identified as Clonostachys rosea. Fusarium verticilloides and Fusarium proliferatum, that produce fumonisins, suspected carcinogenic compounds, were isolated from all kinds of samples, whereas the other species were isolated only from root and stems. Fumonisin B1 was higher in kernels than in silage, while deoxynivalenol, potent protein synthesis inhibiting compound, was detected (at low levels) in grains and silage. A subset of selected strains, representative of all species identified, was also used to evaluate their ability to produce mycotoxins.Fusarium verticillioides, Fusariumproliferatum and Fusarium nygamai produced high levels of fumonisin B1in vitro, as well as beauvericin and enniatins. These findings confirm that, even in hot arid regions, which generally do not favour fungal growth, mycotoxin-producing fungi can be reason of concern for human and animal health.

Chapter 8. Isotopic evidence for protohistoric field locations in northeastern Illinois

AbstractIn the western Great Lakes region of the United States, late prehistoric and early historic Indigenous fields are often difficult to investigate because their archaeological signatures are faint and easily destroyed. They have been identified largely via rare remnants of raised fields and historical records. With the majority of Indigenous fields destroyed, important aspects of cultivation remain ambiguous, especially the ecology of cultivated areas. In addition to archaeological indicators of field location, the choice of specific environmental settings (prairie, wetland, upland forest, etc.) can be encoded in the stable isotope ratios of cultigens. Stable carbon‐ and nitrogen‐isotope ratios of maize kernels and wood charcoal from the Middle Grant Creek site (11WI2739), an early 17th century village in northeastern Illinois, are used to better understand agricultural practices during one of the coldest periods of the Little Ice Age.

Isolation and Phenotypic Identification of Mycotoxigenic Fungi from Stored Maize Kernels within Dutsin–Ma Metropolis, Katsina State

One of the most important effects of post-harvest decay or seed deterioration by fungi is the production of mycotoxins. Mycotoxicosis is a disease of animals and humans following consumption of feeds and foods contaminated by fungi that produce toxic substances called mycotoxins. The study investigated the cultural morphology, microscopic identification, pathogenicity, and mycotoxin production of fungal isolates from 25 stored maize samples collected. Standard microbiological techniques were employed for the analysis of all the samples, Cultural morphology on Potatoes Dextrose Agar revealed diverse colony characteristics, ranging from olive and dark green hues with smooth or spongy surfaces to brownish-pink and dull yellow-green colonies. Microscopic analysis identified six different fungal species, with Aspergillus spp being the most prevalent (72%) and Mucor spp as the least prevalent (6%). Pathogenicity tests on fresh maize demonstrated that all the isolates were pathogenic, causing observable growth on the maize samples. Furthermore, mycotoxin production by the fungal was revealed by evidence of fluorescence under UV radiation, indicating the potential production of aflatoxins. Stored maize kernels from the study area were at risk of fungal attack due to poor storage facilities, poor handling practices and inadequate drying of the grains, which enabled the fungi to grow and produce mycotoxins. Therefore, farmers should be sensitized on the possible risk of fungal attack on grains and be educated on timely harvest, hygienic drying and storage practices of grains.

Kernel density as a population-screening tool for low phytic acid content in maize (Zea mays L.)

Aim: The present study was performed to find association of morphological traits with kernel phytic acid. Methodology: A set of 20 qualitative phenotypic observations were studied in 29 diverse germplasms and two F2 populations. Further correlated traits were quantitatively verified for their correlation and heritability. Results: Maize kernels characterized by low phytate content correlated with reduced seed density traits. Further insights from scanning electron microscopic studies revealed alterations in the distribution pattern of starch granules, among low and high phytate genotypes. Heritability studies indicated a strong heritable nature of the traits viz., kernel density, inorganic phosphorous and phytic acid, and were found to be inter correlated. Interpretation: Intercorrelation and heritable nature of the trait is viewed as a ‘risk index’ that directly influences the success of genetic selection for the phytic acid trait which is highly complex and involves more laboratory experimentation. The selected genotypes may be further screened using biochemical analysis for confirmation. Key words: Correlation, F2 population, Germplasm, Kernel density, Maize, Phytic acid

The contribution of Ca and Mg to the accumulation of amino acids in maize: from the response of physiological and biochemical processes

BackgroundThe quality of maize kernels is significantly enhanced by amino acids, which are the fundamental building blocks of proteins. Meanwhile, calcium (Ca) and magnesium (Mg), as important nutrients for maize growth, are vital in regulating the metabolic pathways and enzyme activities of amino acid synthesis. Therefore, our study analyzed the response process and changes of amino acid content, endogenous hormone content, and antioxidant enzyme activity in kernels to the coupling addition of sugar alcohol-chelated Ca and Mg fertilizers with spraying on maize.Result(1) The coupled addition of Ca and Mg fertilizers increased the Ca and Mg content, endogenous hormone components (indole-3-acetic acid, IAA; gibberellin, GA; zeatin riboside, ZR) content, antioxidant enzyme activity, and amino acid content of maize kernels. The content of Ca and Mg in kernels increased with the increasing levels of Ca and Mg fertilizers within a certain range from the filling to the wax ripening stage, and significantly positively correlated with antioxidant enzyme activities. (2) The contents of IAA, GA, and ZR continued to rise, and the activities of superoxide dismutase (SOD) and catalase (CAT) were elevated, which effectively enhanced the ability of cells to resist oxidative damage, promoted cell elongation and division, and facilitated the growth and development of maize. However, the malondialdehyde (MDA) content increased consistently, which would attack the defense system of the cell membrane plasma to some extent. (3) Leucine (LEU) exhibited the highest percentage of essential amino acid components and a gradual decline from the filling to the wax ripening stage, with the most substantial beneficial effect on essential amino acids. (4) CAT and SOD favorably governed essential amino acids, while IAA and MDA negatively regulated them. The dominant physiological driving pathway for the synthesis of essential amino acids was “IAA-CAT-LEU”, in which IAA first negatively drove CAT activity, and CAT then advantageously controlled LEU synthesis.ConclusionThese findings provide a potential approach to the physiological and biochemical metabolism of amino acid synthesis, and the nutritional quality enhancement of maize kernel.