Maize Grain Research Articles

Thin-layer mathematical modelling of maize in a biomass-powered inclined bed dryer

In this study, the drying kinetics of maize dried in a biomass-powered inclined bed dryer were studied using ten (10) thin-layer mathematical drying models. The drying system recorded an average plenum temperature of 73.54 oC during the drying experiment compared to an average ambient temperature of 28.41 oC. Maize grains with an initial average moisture content of 23.25 % on a wet basis were reduced to 13.61 % average final moisture content over a drying period of 2 hours 40 minutes. The results revealed a moisture extraction rate, drying rate, and drying efficiency of 6.70 kg/h, 9.50 kg/h, and 71.37 %, respectively. The two-term model best describes the thin-layer drying kinetics of maize in the biomass-powered inclined bed dryer based on the coefficient of determination (R2) and root mean square error (RMSE) values of 0.998 and 0.00738, respectively. The two-term model showed a better fit between the experimental and the predicted moisture ratios. The drying process occurred in the falling rate period with an effective moisture diffusivity of 4.65x10-9 m2/s and activation energy of 21.31 kJ/mol. The two-term model was able to imitate the behaviour of the drying process of maize in the drying system. The model would assist in predicting the drying time for different moisture contents of maize in the scale-up of the drying system and, accordingly, help farmers and agro-processors in planning drying schedules. The drying kinetics of other staples like cassava and rice are recommended for further studies using the biomass-powered inclined bed dryer.

Nitrogen Fertilization Boosts Maize Grain Yield, Forage Quality, and Estimated Meat Production in Maize–Forage Intercropping

Crop–livestock integrated systems such as intercropping and crop rotation have been critical for sustainable agriculture, promoting land use intensification throughout the year. The success of these systems under no-till depends on numerous factors, and the choice of forage grass is paramount. In this study, maize grain yield, forage dry matter yield, bromatological quality, and estimated meat production were assessed in a field experiment where maize (Zea mays L.) was intercropped with Guinea grass (Megathyrsus maximus cv. Tanzania) and palisade grass (Urochloa brizantha cv Marandu) under N rates from 0 to 270 kg ha−1. Nitrogen fertilization resulted in the highest forage dry matter yield, on average, 2.9-fold higher than the N-unfertilized treatments. The highest maize grain yield was obtained with 270 kg ha−1 of N, 48% higher than all other treatments. Guinea grass intercropped with maize and fertilized with 270 kg ha−1 of N resulted in an estimated meat production 27% higher than palisade grass at the same N rate. However, at the final cut, Guinea grass fertilized with 270 kg ha−1 of N led to the highest neutral detergent fiber, acid detergent fiber, and cellulose. While palisade grass seems to impose lower competition with maize, Guinea grass increases estimated meat production.

Optimizing polyhalite (POLY-4) use in the maize-wheat system: A comparative case study from upper and Trans Indo-Gangetic plains of India

Increasing complexity in crop nutrient requirement in intensive crop production systems needs alternate multi-nutrient sources. Polyhalite (POLY-4) which contains 14% K2O along withcalcium (17% CaO), magnesium (6% MgO), and sulfur (19% S) can be a possible recourse in this regard. In maize-wheat systems, it was evaluated for productivity, profitability, nutrient usage, and nutrient use efficiency under Indo-Gangetic plain (IGP) zones for consecutive two years (2018-19 and 2019-20). The results revealed that 150% K through POLY-4 produced the maximum maize grain yield under the Trans Indo-Gangetic plains (TGP). The maize grain yield increased by 20.8% and 26.2% under 100% K (POLY-4) and 150% K (POLY-4) over No–K, respectively. But statistically, 100% K (POLY-4) stands similar with both 150% K (POLY-4) and 150% K through muriate of potash (MOP) and equivalent. The trends were noticed under upper Indo-Gangetic plain zones (UGP) also. Similarly, the maximum wheat grain yield (6.12 and 6.29 t/ha under TGP and UGP, respectively) was obtained under 150% K (POLY-4), and remained statistically at par with 100% K (POLY-4), but significantly higher than 150% K (MOP). Under both agro-ecologies i.e. TGP and UGP, the highest system productivity was obtained with recommended N, P, and 150% K application through POLY-4. The added return over NPK remained highest with 150% K (POLY-4) for both maize and wheat. However, higher partial factor productivity for N and S, agronomic, physiological, and translocation efficiencies were noticed under 150% K (POLY-4), and remained at par with 100% K (POLY-4). Increased system yield, added returns, partial factor productivity, agronomic, physiological, and translocation efficiencies under 100% K through POLY-4 (along with recommended N and P) proved its effectiveness as multi-nutrient source for the maize-wheat system under TGP and UGP.

Two crops are better than one for nutritional and economic outcomes of Zambian smallholder farms, but require more labour

Sustainable intensification practices suitable for smallholders in southern Africa will be needed to counteract the impact of future climate change and soil fertility decline in the region. Diversification of maize-based farming systems with grain legumes could play a key role. Here, we compared the performance of different maize-legume diversification strategies (single-row intercropping, strip cropping, and crop rotation) with sole cropped maize under conventional ploughing and Conservation Agriculture in four Zambian districts in the Eastern and Southern Provinces. These options were assessed using the Sustainable Intensification Assessment Framework (SIAF), with metrics representing productive, economic, human, social, and environmental dimensions. Data were collected from on-farm trials over three growing seasons. We found no significant effect of cropping systems on individual maize and legume grain yield across growing seasons, but substantial nutritional and economic benefits of intercropping systems due to simultaneously growing two crops. In particular, maize-legume intercropping strategies (single-row intercropping and strip cropping) resulted in higher energy and protein yield at cropping system level than sole maize and maize-legume rotation, which had positive implications for human nutrition. Although there were increased labour requirements to manage the intercrops, and particularly the strip crops, these cropping systems had much higher net benefits and returns to labour and inputs than the other cropping systems tested. Farmer evaluations however did not show a preference for the intercropping systems over the maize-legume rotation or sole maize, most likely because labour and its availability may be as or more important for farmers than overall cropping system benefits. Soil organic carbon content and soil pH did not differ between the tested cropping systems at the start of the trials and after three cropping seasons, but decreased over this period independently of the cropping system. Overall, the results indicate that maize-legume strip cropping, and single-row intercropping can increase food and nutrition security as well as gross benefits from farming, but this comes at the expense of greater labour requirements throughout the growing season. The latter may be addressed through, e.g., appropriate-scale farm mechanization, if intercropping or strip cropping systems are to become a viable option for labour, not land, constrained farms in Southern Africa.

Editing the 19 kDa alpha-zein gene family generates non-opaque2-based quality protein maize.

Maize grain is deficient in lysine. While the opaque2 mutation increases grain lysine, o2 is a transcription factor that regulates a wide network of genes beyond zeins, which leads to pleiotropic and often negative effects. Additionally, the drastic reduction in 19 kDa and 22 kDa alpha-zeins causes a floury kernel, unsuitable for agricultural use. Quality protein maize (QPM) overcame the undesirable kernel texture through the introgression of modifying alleles. However, QPM still lacks a functional o2 transcription factor, which has a penalty on non-lysine amino acids due to the o2 mutation. CRISPR/cas9 gives researchers the ability to directly target genes of interest. In this paper, gene editing was used to specifically target the 19 kDa alpha zein gene family. This allows for proteome rebalancing to occur without an o2 mutation and without a total alpha-zein knockout. The results showed that editing some, but not all, of the 19 kDa zeins resulted in up to 30% more lysine. An edited line displayed an increase of 30% over the wild type. While not quite the 55% lysine increase displayed by QPM, the line had little collateral impact on other amino acid levels compared to QPM. Additionally, the edited line containing a partially reduced 19 kDa showed an advantage in kernel texture that had a complete 19 kDa knockout. These results serve as proof of concept that editing the 19 kDa alpha-zein family alone can enhance lysine while retaining vitreous endosperm and a functional O2 transcription factor.

Incidences of aflatoxin contaminations in ingredients, feed and products of poultry from two regions in Ghana

Commercial poultry feed required for proper growth of birds and egg production contains essential nutrients with maize as key component. Inadequately dried maize is prone to aflatoxin contamination and therefore when used in feed formulation for poultry may compromise the safety of the feeds and poultry products. This study investigated the levels of aflatoxins in feed ingredients, feed and poultry products sampled from Eastern and Greater -Accra regions of Ghana. The aflatoxin levels of B1, B2, G1, and G2 were determined using a High-Performance Liquid Chromatography (HPLC) methodology. Main feed ingredients used were fishmeal, cotton seed cake, soya meal, rice, wheat and maize bran as well as maize grains. There was correlation between the level of aflatoxins and moisture content in poultry feed ingredients. All the poultry feeds (100 %) analysed showed the presence of aflatoxins with total aflatoxins recorded ranging from 5.32 to 29.88 μg/kg. Maize samples of the poultry feeds, from all two regions, revealed maize to be a major contributor to the overall total aflatoxin contents found in the feed. Five (5) out of ten (10) communities investigated in the two (2) regions where the poultry feeds were examined recorded total aflatoxin levels in maize above the Ghana Standard Authority (GSA) specification of 20 μg/kg. Aflatoxins G1 and G2 were not detected in all samples of chicken meat and eggs. Total aflatoxin levels recorded for all chicken meat and eggs were below GSA specification of 5 μg/kg; implying that these products were safe for consumption.

A meta-analysis of hairy vetch as a previous cover crop for maize

BackgroundThe use of hairy vetch (Vicia villosa Roth.) as cover crop is increasing worldwide. Hairy vetch can contribute as a nitrogen (N) source with potential to impact subsequent high N demanding cereals such as maize (Zea mays L.). Contrasting literature results emphasize the need for a global synthesis analysis to quantify changes in maize yield after hairy vetch. ObjectivesA meta-analysis was conducted to i) quantify maize yield response to hairy vetch as previous crop, ii) explore hairy vetch influence on fertilized and non-N fertilized maize yields, and iii) assess the tillage and environment factors on maize yield response to hairy vetch. MethodsThe global systematic search yielded 23 publications selected by the following criteria, i) hairy vetch dry matter at the end of the season, ii) maize grain yield, and iii) experimental design with (Mzhv) and without (Mzcontrol) hairy vetch treatments. Information such as N fertilization for maize, N accumulation in hairy vetch, organic matter, and tillage before maize sowing were recorded. Hairy vetch effects (effect size) were expressed as a ratio (percentage of grain yield variation in Mzhv/Mzcontrol). ResultsUnder non-N fertilization (n = 9), results revealed hairy vetch had mostly a positive effect, ranging from 13 to 45% (n = 6). In contrast, N-fertilized maize (n = 20) showed a high chance of neutral effects (n = 12), moderate probability of positive yield impact (7 to 38%, n = 6), and a low likelihood of negative effects (−32 and −17%, n = 2). Notably, maize yields improved by 21–25% when the N accumulation in hairy vetch ranged from 95 to 150 kg ha−1 and N rate from 0 to 120 kg ha−1. Non-N-fertilized maize exhibited a 14% increase in response in no-till systems and a 31% increase with conventional tillage. ConclusionThis study summarizes potential benefits of hairy vetch preceding maize. Yet, the heterogeneous outcomes deserve further exploration in terms of environment and management factors.

Optimal Plant Density Improves Sweet Maize Fresh Ear Yield without Compromising Grain Carbohydrate Concentration

It is crucial to synergistically improve the yield and quality of sweet maize by implementing precise and strategic planting methods. However, a comprehensive understanding of how increasing plant density affects the sweet maize fresh ear yield, grain-filling rate, and grain carbohydrate concentration is not fully understood. Thus, a field experiment was performed using a split-plot design in Southeast China in 2021 and 2022, involving four sweet maize varieties (MT6855 and WT2015 were compact-type varieties, XMT10 and YZ7 were flat-type varieties) and three plant densities (D1: 4.5 plants m−2; D2: 6.0 plants m−2; and D3: 7.5 plants m−2). The results showed that an increasing plant density markedly increased the fresh ear yield of sweet maize varieties (MT6855 and WT2015) over the two years. However, it did not influence the fresh ear yield of XMT10 and YZ7. Across all four varieties in 2021 and 2022, the increasing plant density decreased the sweet maize filled ear length, while it did not affect the grain soluble solid concentration and grain residue ratio. The sweet maize grain weight, the maximum grain-filling rate, and the mean grain-filling rate decreased significantly with the increase in planting density across all four varieties. However, plant density did not significantly affect the grain soluble sugar, sucrose, fructose, and starch concentrations across different varieties at most stages during the grain filling. The current study also found that the sweet maize fresh ear yield was dramatically positively correlated with ears ha−1, grains per ear, grain-filling rate, and grain starch concentration but negatively correlated with the bare plant rate. Notably, a parabolic relationship existed between the fresh ear yield and 100-grain weight. These findings suggest that optimizing the plant density, particularly with compact-type varieties, can improve the sweet maize fresh ear yield without decreasing its quality.

Transcriptome Analysis of Maize Ear Leaves Treated with Long-Term Straw Return plus Nitrogen Fertilizer under the Wheat-Maize Rotation System.

Straw return (SR) plus nitrogen (N) fertilizer has become a practical field management mode to improve soil fertility and crop yield in North China. This study aims to explore the relationship among organic waste, mineral nutrient utilization, and crop yield under SRN mode. The fertilizer treatments included unfertilized (CK), SR (straws from wheat and corn), N fertilizer (N), and SR plus N fertilizer (SRN). SRN treatment not only significantly increased the grain yield, net photosynthetic rate, and transpiration rate but also enhanced the contents of chlorophyll, soluble sugar, and soluble protein and increased the activities of antioxidant enzymes but reduced intercellular CO2 concentration and malondialdehyde (MDA) content when compared to other treatments. There were 2572, 1258, and 3395 differentially expressed genes (DEGs) identified from the paired comparisons of SRvsCK, NvsCK, and SRNvsCK, respectively. The transcript levels of many promising genes involved in the transport and assimilation of potassium, phosphate, and nitrogen, as well as the metabolisms of sugar, lipid, and protein, were down-regulated by straw returning under N treatment. SRN treatment maintained the maximum maize grain yield by regulating a series of genes' expressions to reduce nutrient shortage stress and to enhance the photosynthesis of ear leaves at the maize grain filling stage. This study would deepen the understanding of complex molecular mechanisms among organic waste, mineral nutrient utilization, crop yield, and quality.

Smallholder Cropping Systems Contribute Limited Greenhouse Gas Fluxes in Upper Eastern Kenya

The contribution of smallholder farming systems to the National greenhouse gas (GHG) budget is missing in most developing countries, including Kenya. Data on the contribution of smallholder cropping systems to the GHG balance is essential for realising Sustainable Development Goal 13 on climate action, i.e., on nationally determined contributions (NDCs) and in compliance with the Paris Agreement. Do smallholder farming systems act as nature-based solutions for greenhouse gas emissions reduction? This study evaluated GHG emissions from cropping systems under on-farm smallholder farming conditions. We had five cropping systems on two smallholder farms: sole maize, maize-bean intercrop, coffee, banana, and agroforestry. Gas samples were collected using three static chambers per cropping system. The gas samples were analysed using gas chromatography (GC) fitted with a 63Ni-electron capture detector (ECD) for N2O and flame ionisation detector (FID) for CH4 and CO2 using N as carrier gas. Cumulative annual fluxes of (CH4, N2O, and CO2) varied significantly in farms one and two across the cropping systems. The cumulative soil GHG fluxes ranged from -1.34 kg CH4-C ha−1 yr−1 under agroforestry to -0.77 kg CH4-C ha−1 yr−1 under banana for CH4, 0.30 kg N2O-N ha−1 yr−1 to 1.23 kg N2O-N ha−1 yr−1 for N2O and 5949 kg CO2-C ha−1 yr−1 to 12954 kg CO2-C ha−1 yr−1 for CO2. The maize grain yields ranged from 0 to 3.38 Mg ha−1. The N2O yields scaled emissions ranged from 0.10 to 0.26 g kg−1 maize and 0.68 to 1.30 g kg−1 beans. Smallholder farmers in Upper Eastern Kenya contribute a limited amount of soil GHG emissions and thus could act as a nature-based solution for lowering agricultural emissions.

Diet Mixing and Supplementation Present an Opportunity to Increase the Use of Encroaching Woody Plants by Goats.

Along with the woody plant expansion that is predicted to continue at the expense of the grassy layer is the increasing societal demand for animal protein and livestock products. Unless concerted efforts by land users, ecologists, and animal scientists are made to increase the utilization of trees and shrubs as forage, it will be impossible to meet future demand for meat and meat products. We conducted two short-term pen experiments to determine the effects of (1) supplementation with polyethylene glycol (PEG-a polymer purported to bind and neutralize the negative effects of tannins), a high-protein source (soybean meal), and a high-energy source (yellow maize grain) and (2) diet mixing (single-species vs. multispecies diets) on the intake of condensed tannin-rich woody plants (i.e., Searsia lancea, S. pyroides, and Euclea crispa) by goats. While all three forage species were used in the diet mixing experiment (Exp. 2), only E. crispa was used in the supplementation experiment (Exp. 1). Supplementing goats with energy- and protein-rich sources significantly increased the intake of E. crispa (p < 0.05), 713.4 g ± 13.5 and 760 g ± 28.9, respectively, whereas those on the control diet maintained their intake at 540.32 g ± 11.2. Although PEG tended to increase the consumption of E. crispa by goats, the observed increase was not significant (p > 0.05) from that observed in other treatments. In the diet mixing experiment, goats offered a combination of all three forage species attained substantially higher dry matter intakes compared to the goats offered these species individually (p < 0.05). While longer-term field experiments are needed in the African savannas, we postulate from the current results that management strategies that provide animals with (1) a variety of species in the diet vs. monocultures and (2) a combination of nutrient-rich and tannin-rich species may improve the ability of goats to consume chemically defended woody plants.

Potential of melatonin in enhancing antioxidant defense system and yield of maize (Zea mays L.) hybrids under saline condition

Melatonin is a multi-signaling plant hormone that significantly regulate plant growth and development under stress environment. Since a very few crop species have been investigated to disclose the role of exogenously applied melatonin on salt stress, in the current experiment, we investigated the effects of melatonin application by measuring the growth, physio-biochemical and yield attributes of two maize hybrids (2225 and 8711) in saline field (8.9 dS m−1) with two levels of melatonin (0.5 and 1.0 mM). Maize plants from both hybrids grown in saline field show reduced plant growth, fresh and dry biomass, low water contents, grain yield, reduced activities of antioxidant enzymes and poor K+/Na+ ratio due to higher Na+ influx and reduced potassium uptake by plant roots. Our results revealed that foliar application of melatonin at 1.0 mM level on salt stressed maize seedlings alleviated salt induced reduction in plant height, chlorophyll and water contents, reduced the production of proline contents and antioxidant stress indicators (malondialdehyde and hydrogen peroxide contents) and increase cob length along with improved activities of antioxidant enzymes and nutrients concentration in maize grain. Moreover, it was noticed that maize hybrid 2225 show improved growth and eminently responded to melatonin application under all treatments as compared to maize hybrid 8711. The results of the current experiment exhibit the potential of melatonin in mitigate the hazardous effects of salt stress on maize and our findings can provides scientific information for the researchers working on saline agriculture to disclose the potential benefits of melatonin application in achieving sustainable production from salt affected soils.

Potential Impacts of Certain N2-Fixing Bacterial Strains and Mineral N Doses for Enhancing the Growth and Productivity of Maize Plants.

The enhancing effect of N2-fixing bacterial strains in the presence of mineral N doses on maize plants in pots and field trials was investigated. The OT-H1 of 10 isolates maintained the total nitrogen, nitrogenase activities, IAA production, and detection of NH3 in their cultures. In addition, they highly promoted the germination of maize grains in plastic bags compared to the remainder. Therefore, OT-H1 was subjected for identification and selected for further tests. Based on their morphological, cultural, and biochemical traits, they belonged to the genera Azotobacter. The genomic sequences of 16S rRNA were, thus, used to confirm the identification of the genera. Accordingly, the indexes of tree and similarity for the related bacterial species indicated that genera were exactly closely linked to Azotoacter salinestris strain OR512393. In pot (35 days) and field (120 days) trials, the efficiencies of both A. salinestris and Azospirillum oryzea SWERI 111 (sole/dual) with 100, 75, 50, and 25% mineral N doses were evaluated with completely randomized experimental design and three repetitions. Results indicated that N2-fixing bacteria in the presence of mineral N treatment showed pronounced effects compared to controls. A high value of maize plants was also noticed through increasing the concentration of mineral N and peaked at a dose of 100%. Differences among N2-fixing bacteria were insignificant and were observed for A. oryzea with different mineral N doses. Thus, the utilization of A. oryzea and A. salinestris in their dual mix in the presence of 75 followed by 50% mineral N was found to be the superior treatments, causing the enhancement of vegetative growth and grain yield parameters of maize plants. Additionally, proline and the enzyme activities of both polyphenol oxidase (PPO) and peroxidase (PO) of maize leaves were induced, and high protein contents of maize grains were accumulated due to the superior treatments. The utilization of such N2-fixing bacteria was, therefore, found to be effective at improving soil fertility and to be an environmentally safe strategy instead, or at least with low doses, of chemical fertilizers.

Yield and plant height predictions of irrigated maize through unmanned aerial vehicle in North Florida

Monitoring crops and producing correct yield estimates are both crucial components of decision-making in agricultural systems. This is particularly important for crops like maize, with a national gross production value above US $82 billion in 2021. Several crop parameters, e.g., plant height (PH), leaf nutrient status, etc., are in use for improving maize grain yield (MGY) prediction models. Traditional PH measurements can be time-consuming and labor-intensive; thus, unmanned aerial vehicles (UAVs) might be efficient and practical tools to predict in-season MGY. Two small-plot trials were conducted in North Florida to estimate in-field PH (IFPH) using UAVs (UAV-PH) and compare different regression approaches to estimate MGY using different time points (from 17 to 133 days after planting [DAP]). A multispectral camera was mounted onto an Aurelia X6 Standard hexacopter to capture crop canopy height. Overall, the IFPH values were higher than UAV-PH but strongly correlated (r = 0.95). Moderate to strong correlations were observed between MGY and PH at all time points except 17 DAP. The prediction of MGY using IFPH or UAV-PH was better through machine learning algorithms (Random forest regressor [RFR] and Support vector regression [SVR]) compared to simple/multiple linear regression (S/MLR), with R2, MAE, RMSE, and nRMSE ranges of 0.91–0.94, 553.86–1574.62 kg ha−1, 708.94–195.04 kg ha−1, and 14.2–39.1 % for best-performing models of RFR and SVR, respectively. Furthermore, S/MLR usually overestimated low-yielding plots (MGY < 12000 kg ha−1) and underestimated high-yielding plots (MGY > 12000 kg ha−1). The results showed that UAVs are a potential tool for quicker decision-making in maize cropping systems in North Florida since the crop-height model accurately estimated ground PH measurements (IFPH) at different time points.

Effect of Maize Hybrid in Complete Feed on the Production Performance and Economic Considerations in Laying Hens

The nutritional value of maize grain can be influenced by its genetic background, which can lead to differences that could affect laying hens due to the high proportion of maize hybrids in the complete feed. This study aimed to investigate the effects of modern maize hybrids on hen production and egg quality. Dietary treatments differed only in a grain of 15 high-yielding maize hybrids, added at a fixed proportion of 600 g kg−1 and without additional pigments. By 3 in each cage, 225 Lohmann Brown hens were allocated to 15 dietary treatments in a completely randomized block design (15 treatments × 5 cages). The experiment lasted 10 weeks, during which the number and weight of eggs were recorded daily, and diet intake was recorded weekly. Eggs for quality analysis were collected once per week during the last five weeks of the experiment. Dietary treatments differed (p &lt; 0.05) in complete feed intake (119.7–123.1 g), egg weight (58.02–61.51 g), daily egg mass (56.17–60.16 g), and feed conversion ratio (2.01–2.19). As expected, dietary treatments did not affect egg traits such as shape index, albumen height, Haugh units, shell strength, thickness, and weight, but differed (p &lt; 0.05) in yolk color (6.28–8.76) and yolk (14.74–16.03 g) and albumen (34.39–39.29 g) weights. The findings suggest that using different maize hybrids in complete feeds used in egg production systems may lead to small but significant differences in some hen production and egg quality traits, which in turn affect farmers’ income.

Dynamics and genetic regulation of macronutrient concentrations during grain development in maize

Nitrogen (N), phosphorus (P), and potassium (K) are essential macronutrients that are crucial not only for maize growth and development, but also for crop yield and quality. The genetic basis of macronutrient dynamics and accumulation during grain filling in maize remains largely unknown. In this study, we evaluated grain N, P, and K concentrations in 206 recombinant inbred lines generated from a cross of DH1M and T877 at six time points after pollination. We then calculated conditional phenotypic values at different time intervals to explore the dynamic characteristics of the N, P, and K concentrations. Abundant phenotypic variations were observed in the concentrations and net changes of these nutrients. Unconditional quantitative trait locus (QTL) mapping revealed 41 non-redundant QTLs, including 17, 16, and 14 for the N, P, and K concentrations, respectively. Conditional QTL mapping uncovered 39 non-redundant QTLs related to net changes in the N, P, and K concentrations. By combining QTL, gene expression, co-expression analysis, and comparative genomic data, we identified 44, 36, and 44 candidate genes for the N, P, and K concentrations, respectively, including GRMZM2G371058 encoding a Dof-type zinc finger DNA-binding family protein, which was associated with the N concentration, and GRMZM2G113967 encoding a CBL-interacting protein kinase, which was related to the K concentration. The results deepen our understanding of the genetic factors controlling N, P, and K accumulation during maize grain development and provide valuable genes for the genetic improvement of nutrient concentrations in maize.

Nutrient Digestibility and Blood Composition of Broiler Chickens Fed Diets Containing Biodegraded Sweet Orange (Citrus sinensis) Fruit Peel

Aims: To determine the nutrient digestibility and blood composition of broiler chickens fed biodegraded sweet orange fruit peel-based diets.&#x0D; Study Design: Completely randomized design.&#x0D; Place and Duration of Study: Livestock Research Farm, Federal University of Agriculture Makurdi, Nigeria; fifty-six days&#x0D; Methodology: Sweet orange peels and cattle rumen content were collected. Rumen content was mixed with water at a ratio 1 kg: 1 litre and sieved to get rumen filtrate (RF). RF was mixed with Sweet orange peels at a ratio of 1 litre: 2.5 kg and fermented for 48 hours, sun-dried, milled, and added to broiler diets at different levels: 0% (T1), 5% (T2), 10% (T3), 15% (T4), and 20% (T5). A total of 150 day-old chicks, randomly assigned to five dietary treatments and three replicates per treatment were raised in a 56-day feeding trial. Three chickens of average live body weight similar to the treatment group average were selected and used to determine nutrient digestibility and blood composition.&#x0D; Results: The results showed that the coefficient of digestibility of dry matter, crude protein, crude fibre, ether extract and nitrogen-free-extract did not differ significantly (P &gt; .05) among the treatment groups. Haematological indices; haemoglobin, red blood cell (RBC), packed cell volume, mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH), did not differ significantly (P &gt; .05) across the dietary groups, while white blood cell (WBC) and mean corpuscular haemoglobin concentration (MCHC) varied significantly (P &lt; .05). Serum indices; total protein (TP), globulin, glucose, cholesterol, and alkaline phosphatase were significantly affected (P &lt; .05) by the experimental diets, while albumin, aspartate transaminase and alanine transaminase did not differ significantly (P &lt; .05) across the dietary groups.&#x0D; Conclusion: Biodegraded sweet orange peel-based diets can replace maize grains up to 20% without affecting nutrient digestibility or having any adverse effect on blood constituents of broiler chickens.

Balancing phosphorus fertilization for sustainable maize yield and soil test phosphorus management: A long-term study using machine learning

ContextExcessive phosphorus (P) applications to ensure enhanced crop growth and increased profitability are commonly used, leading to declined P use efficiency and high P accumulation in most cultivated soils across north-western India. However, the effects of consistently applying excessive P fertilizers on soil test P (STP) levels, P availability, and maize production outcomes are poorly understood. ObjectivesThe study aims to find the long-term impacts of different fertilizer P application rates on maize yield, agronomic P efficiency, optimal P rates for yield maximization, and predictive models for sustainable crop production and environmental protection across soils with different STP status. MethodsThe current study collected and analysed maize plant and soil data spanning from 2011 to 2021 from an ongoing long-term field experiment conducted on three different STP status soils i.e., medium P (MPS), high P (HPS), and very high P (VHPS) soils. The experiment involves five different fertilizer P application rates No-P, 13, 26, 39, and 52 kg P ha−1. ResultsThe results indicated a significant increase in maize grain yield and P bioavailability with the application of 13 kg ha−1 of fertilizer P in VHPS (>50.0 kg P ha−1) and 26 kg ha−1 in both HPS (22.5–0.0 kg P ha−1) and MPS (12.5–22.5 kg P ha−1). Improved agronomic efficiency reducing P rate to half of the recommended 26 kg P ha−1 was estimated in VHPS. The economically optimal P rate (EOPR) model consistently sustains crop yield with lower P rates. Among the different machine learning algorithms, multiple linear regression (MLR) was found more reliable in predictive accuracy. The decrease in predicted grain yield and increase in predicted soil P accumulation at P rates of 26 kg P ha−1 and above in varying P status soils underscores the need for judicious P fertilization practices to avoid negative impacts on yield. ConclusionsThe P application required to obtain an average maize yield of 6000 kg ha−1 with relatively high P use efficiency, fertilizer P applications of 35.2 kg ha−1 in VHPS, 37.1 kg ha−1 in HPS, and 41.1 kg ha−1 in MPS based on STP status is more economical. Smart agriculture, using machine learning algorithms helps in ensuring effective P utilization over the long term while minimizing negative ecological impacts. ImplicationsThe sustainable growth of maize crops will necessitate a reduction in P application rates, and P optimization should need further attention to explore the microbial dissolution potential of residual P.

Tithonia diversifolia Improves In Vitro Rumen Microbial Synthesis of Sheep Diets without Changes in Total Gas and Methane Production

Among the alternatives identified as capable of making livestock farming a more efficient activity and reducing its environmental impact, the use of feeds with high digestibility and the use of non-conventional fodder species can be highlighted. Tithonia diversifolia (Hemsl.) A. Gray (TD) has already gained attention as a feed for ruminants. Nonetheless, there has been little discussion about the impacts of this plant on the rumen dynamics that lead to better animal performance. The aim of this study was to assess how increasing levels of TD could affect ruminal microbial biomass synthesis, degradability, and in vitro gas production (IVGP) of diets. Four diets were evaluated: a control diet (TD0: 400 g kg−1 soybean meal and maize grain, and 600 g kg−1 Tifton 85 hay (Cynodon spp.)) and three increasing levels of TD (TD9: 90, TD27: 270, and TD45: 450 g kg−1–dry matter basis) as a replacement for dietary roughage. A 96 h IVGP assay was carried out and five incubation times (2, 4, 10, 24, and 96 h) were used for degradability determination. Gas produced, methane (CH4), degradability of organic matter (IVDOM), short-chained fatty acid (SCFA) production, partitioning factor (PF), and microbial biomass (MB) were evaluated among treatments. There was no significant effect (p &gt; 0.05) between TD inclusion and IVGP at most incubation times; only at 6 h of incubation did gas production increase linearly with TD inclusion (R2 = 0.19; p &lt; 0.05). TD inclusion had no effects on CH4. IVDOM increased linearly with TD inclusion at 6 and 10 h, with TD45 being more degradable than the control diet at 6 h only. There was a positive linear relationship (R2 = 0.20; p &lt; 0.05) between TD inclusion and PF. TD45 had significantly higher PF values than the control. MB also increased linearly (R2 = 0.30; p &lt; 0.05) with TD inclusion, and all diets with TD had significantly more MB than the control diet. The inclusion of TD at the levels used in this work was revealed to have a positive impact on microbial protein synthesis, which could be related to the higher microbial efficiency of increased substrate quality.

A potential candidate gene associated with the angles of the ear leaf and the second leaf above the ear leaf in maize

BackgroundLeaf angle is a key trait for maize plant architecture that plays a significant role in its morphological development, and ultimately impacting maize grain yield. Although many studies have been conducted on the association and localization of genes regulating leaf angle in maize, most of the candidate genes identified are associated with the regulation of ligule-ear development and phytohormone pathways, and only a few candidate genes have been reported to enhance the mechanical strength of leaf midrib and vascular tissues.ResultsTo address this gap, we conducted a genome-wide association study (GWAS) using the leaf angle phenotype and genotyping-by-sequencing data generated from three recombinant inbred line (RIL) populations of maize. Through GWAS analysis, we identified 156 SNPs significantly associated with the leaf angle trait and detected a total of 68 candidate genes located within 10 kb upstream and downstream of these individual SNPs. Among these candidate genes, Zm00001d045408, located on chromosome 9 emerged as a key gene controlling the angles of both the ear leaf and the second leaf above the ear leaf. Notably, this new gene’s homolog in Arabidopsis promotes cell division and vascular tissue development. Further analysis revealed that a SNP transversion (G/T) at 7.536 kb downstream of the candidate gene Zm00001d045408 may have caused a reduction in leaf angles of the ear and the second leaf above the ear leaf. Our analysis of the 10 kb region downstream of this candidate gene revealed a 4.337 kb solo long-terminal reverse transcription transposon (solo LTR), located 3.112 kb downstream of Zm00001d045408, with the SNP located 87 bp upstream of the solo LTR.ConclusionsIn summary, we have identified a novel candidate gene, Zm00001d045408 and a solo LTR that are associated with the angles of both the ear leaf and the second leaf above the ear leaf. The future research holds great potential in exploring the precise role of newly identified candidate gene in leaf angle regulation. Functional characterization of this gene can help in gaining deeper insights into the complex genetic pathways underlying maize plant architecture.