Crop Grain Research Articles

Crop nutrition and grain yield as affected by phosphorus fertilization and continued use of phosphogypsum in an Oxisol under no-till management

ABSTRACT The benefits of applying phosphogypsum to the soil are widely known. However, the effect of phosphogypsum on phosphate fertilization efficiency is still unclear. A long-term field experiment was performed on an Oxisol in Parana State, Brazil to evaluate the effects of triple superphosphate (TSP) and phosphogypsum application rates on nutrition and grain yield of soybean, wheat, and black oat under no-till. Applying TSP in the sowing furrow of soybean and wheat increased soybean yield by 14 to 24%, wheat yield by 57%, and black oat yield by 78%. Soybean yields varied in different cropping seasons in response to phosphogypsum application (with no response to increases of up to 15% in yield), while phosphogypsum increased wheat yield by 23% and black oat yield by 59%. The water balance during crop flowering possibly interfered on crop yield response to phosphogypsum. The use of phosphogypsum increased agronomic P-use efficiency by 20%, regardless of the TSP-P application rates. Changes in P-leaf concentration caused by TSP fertilization and phosphogypsum use had a positive impact on crop grain yield. Our results reveal that the continued use of phosphogypsum to alleviate subsoil acidity could increase the phosphate fertilization efficiency and improve crop yield performance under drought stress.

Livestock Farmers Warned Over Mycotoxin Levels in Feed Grains

Widespread drought across Europe during the 2022 grain growing season has left livestock farmers wary as the dry spell caused higher levels of mycotoxins. The drought has increased the presence of moulds which, in turn, bumped up the mycotoxin levels in new crop grains and forages. Mycotoxins are produced by certain species of fungus and are a big concern for livestock producers as they can influence feed quality and subsequent animal health and performance. The grim news was delivered by an analysis of crops grown in 2022 and sampled in a joint effort between Alltech and SGS, a global leader in mycotoxin testing and certification. The Alltech 2022 European Harvest Analysis collected data for key feed ingredients on a regional level, and the final results indicate moderate to high levels of mycotoxin risk. Over 1,000 samples of the most common grains and forages produced and used in the European livestock industry were taken as part of the work. Samples have been collected from farms or animal feed production sites in 20 different countries, offering a representative picture of the contamination risk in all regions, with an overall moderate to high risk. Dr Radka Borutova, European technical support manager with the Alltech mycotoxin management team, said the current results look very similar to the analysis performed in 2021, with the aflatoxin issue in central and south eastern Europe dominating the headlines and creating the greatest challenge for feed and livestock producers to manage. Although this analysis gives a robust assessment of the mycotoxin risk in Europe this year until you actually test the ingredients that you are using in your business, it can be difficult to implement an effective control plan. Some main results from the analysis reported that 100% of samples contained mycotoxins, with 79% containing 2 or more. On average, each sample contained 4.5 mycotoxins with aflatoxins, type B trichothecenes, fumonisins and emerging mycotoxins the most dominant groups detected. A total of 67 corn samples exceeded aflatoxin regulatory limits for feed usage, which is a major concern for livestock farmers. Mitigating mycotoxins is a huge challenge with no universal solution. However, breakthroughs are being made all the time in mycotoxin control and prevention, mycotoxin testing and the impact of mycotoxins on livestock. For the second year running, aflatoxin contamination of corn in central and south eastern Europe is a dominant issue for feed and livestock producers to consider as they begin to purchase and use ingredients during the coming feeding season.

Comprehensive Structural and Functional Characterization of a Seed γ-thionin as a Potent Bioactive Molecule Against Fungal Pathogens and Insect Pests.

Fungi and insect pests ruin stored crop grain, which results in millions of dollars of damage, presenting an ongoing challenge for farmers in addition to diminishing the safety of stored food. A wide-range defensive system against pathogens is needed to reduce or even eliminate the dependence of the crop yield upon the use of pesticides. Plant defensins (γ-thionins) are antimicrobial peptides (AMPs) that are a component of the host defense system. They are known to interact with cell membranes to exhibit antifungal and insecticidal activity. They exhibit a broad range of activities against fungi and insects and are effective at low concentrations. Thionins act on membranes, greatly reducing the development of pathogen resistance. The aim of this study is to investigate a bioactive molecule that acts against fungal pathogens and stored grain insect pests. γ-thionin protein was extracted from Brassica oleracea L. var. capitata f. alba (white cabbage) seed powder in phosphate buffer (100 mM, pH 7.0) and was identified by MALDI-TOF/TOF. The crude extract was subjected to 70% ammonium sulfate saturation followed by gel filtration chromatography. The disc diffusion assay along with a microtiter bioassay was used to determine the antifungal activity of the protein against phytopathogenic fungi. The insecticidal efficacy was evaluated by feeding insect pests with food contaminated with the purified protein. Additionally, an in silico molecular structure prediction study of the protein was performed using Auto Dock Vina for molecular docking of the protein with either fungal membrane moieties or α-amylase from Tenebrio molitor L. MD simulations of protein-ligand complexes were conducted using Schrodinger's Desmond module. γ-Thionin (BoT) was purified from white cabbage seeds and showed 100% homology with thionin (Brassica oleracea L. var. viridis) and 80% homology with defensin-like protein 1 (Raphanus sativus L.), respectively. BoT significantly inhibited the mycelial growth of Aspergillus niger van Tieghem and Aspergillus flavus Link at a concentration of 2 μM. Similarly, 0.12 μM BoT treatment resulted in significant mortality of Tribolium castaneum Herbst and Sitophilus oryzae L. Molecular docking and MD simulation of BoT confirmed the strong binding affinity with fungal membrane moieties (phosphatidylinositol 4,5-bisphosphate and phosphatidic acid), which causes disruption of the cell membrane and leakage of the cellular contents, leading to cell death. BoT blocked the active site of α-amylase, and as a result of the inactivation of this gut enzyme, the digestive systems of insects were disturbed, resulting in their deaths. This study revealed that γ-thionin is a good antifungal and insecticidal agent that could be used as an alternate to fungicides and insecticides.

Integration of Transcriptome and Metabolome Analyses Reveals the Mechanistic Basis for Cadmium Accumulation in Maize.

Cadmium (Cd) pollution in soil has become a major environmental issue worldwide. However, the underlying molecular mechanism of low grain-Cd accumulation (GCA) in maize is still largely unknown. Herein, we report the mechanistic basis for low GCA in maize by a multiomics approach. The low GCA genotype L63 showed normal vacuolar formation and a lower capacity of xylem loading of Cd than the high-accumulator L42 under Cd stress. Transcriptomic sequencing identified 84 low-GCA-associated genes which are mainly involved in the S-adenosylmethionine (SAM) cycle, metal transport, and vacuolar sequestration. A metabolome analysis revealed that L63 plants had a more active SAM cycle and a greater capacity for terpenoid synthesis and phenylalanine metabolism than L42. Combining the analysis of transcriptome and metabolome characterized several genes as key genes involved in the determination of Cd accumulation. Our study identifies a mechanistic basis for low Cd accumulation in maize grains and provides candidate genes for genetic improvement of crops.

Multiple ALMT subunits combine to form functional anion channels: A case study for rice ALMT7

The Aluminum Activated Malate Transporter (ALMT) family members are anion channels that play important roles in organic acid transport, stress resistance, growth, development, fertilization and GABA responses. The rice malate permeable OsALMT7 influences panicle development and grain yield. A truncated OsALMT7 mutant, panicle apical abortion1 (paab1) lacking at least 2 transmembrane helices, mediates reduced malate efflux resulting in yield reducing. Here, we further investigated the contribution of OsALMT7 transmembrane helices to channel activity, using heterologous expression in Xenopus laevis oocytes. We further found that OsALMT7 formed as a homomer by co-expressing OsALMT7 and paab1 proteins in oocytes and detecting the physical interaction between two OsALMT7, and between OsALMT7 and paab1 mutant protein. Further study proved that not just OsALMT7, mutants of TaALMT1 inhibit wild-type TaALMT1 channel, indicating that ALMTs might perform channel function as homomers. Our discovery brings a light for ion channel structure and homomultimer regulation understanding for ALMT anion channels and potential for crop grain yield and stress response improvement in the context of the essential role of ALMTs in these plant processes.

Long‐term manure application enhances organic carbon and nitrogen stocks in Mollisol subsoil

AbstractSubsoils contain half of the total soil organic carbon (SOC) that is supposed to be relatively more persistent than that present in the topsoil. Improving SOC and total nitrogen (TN) stocks in croplands is crucial to mitigate climate change and ensuring food security. However, our insight into how the management practices and climatic variables influence stocks of SOC and TN, and crop grain yields in the soil profile is limited. In this study, we assessed the long‐term impacts of mineral and manure fertilizers on SOC and TN stocks at soil profile levels (up to 100 cm), and cropping system (wheat–maize–soybean) grain yields. Results indicated that in the top 0–40‐cm layers SOC and TN stocks were the highest in manure plus mineral fertilizers (MNPK) compared with control, that is, non‐fertilized control (CK). Conversely, compared with NPK, sole application of manure (M) clearly increased SOC stocks by 19%, 40%, and 39% and TN stocks by 51%, 105%, and 116% in 40–60, 60–80, and 80–100 cm, respectively (p < 0.05). Moreover, Pearson correlation revealed that climate variables, that is, mean annual temperature (MAT) affected both SOC and TN stocks in 0–40‐cm layers only of the soil profile. Our findings implicated that the sole application of manure (M) is vital to augment SOC and TN sequestration, particularly in the subsurface layers. However, trade‐offs between SOC and TN sequestration and crop yields should also need to be considered while making recommendations for SOC and TN stocks maintenance and increasing crop productivity in terms of management strategies.

Effectiveness of different protein sources and lysine levels in diets for broiler chickens

The article highlights current data on the biological role of the most crucial feed nutrients - protein and lysine in the feeding of broiler chickens and their particular importance in the vital activity of the bird's body. A description of the value and quality of the main types of compound feed for poultry, recipes of compound feed with different protein and lysine content for specific age groups of broiler chickens, and practical advice on the peculiarities of feeding and rearing of poultry are given. Current brief information on amino acid feed additives and general features of more rational and practical use of various protein feed of both vegetable and animal origin in poultry feeding of meat crosses – grains of cereal crops, processed products of oil crops – soy, sunflower, and many other components are provided. Theoretically and experimentally, the expediency of using different essential feed protein sources, differing in amino acid composition and bioavailability, in poultry feeding rations has been substantiated. In particular, the main principles of adequate feeding of broilers with compound feed with an increased level of crude protein of vegetable origin and a lower level of animal protein are described. Brief information on the effectiveness of safe levels of lysine of synthetic origin in the diet based on a variety of local feeds when growing broiler chickens in the conditions of a poultry farm in the western region are presented. It was established that compound feed with a significantly increased protein content of various origins – 24 %, 22 % and 20 % – positively affects broiler chickens' productivity. The highest level of productivity was noted for the lysine content in broilers' compound feed in the first growing period – 1,22 %, in the second – 1,14 % and in the third – 1,09 %. The high quality, nutritional value, and beneficial effects of amino acid premixes are directly influenced by the available feed raw materials, mainly of vegetable origin, used for the production of compound feed in the conditions of a broiler poultry farm, the uniformity of mixing with the appropriate quality feed and the optimal dosage of amino acids in each portion of the feed mixture.

Quality Characteristics of Noodles Processed from Rice Grains of the Ratoon Crop

Rice noodles are usually manufactured using rice grains of the main crop. There is limited information available on rice noodles processed from ratoon rice grains. In this study, two-year field experiments were conducted to compare the cooking and texture properties of noodles and the grain chemical properties of ratoon crops with those of main crops from two rice cultivars (Guichao 2 and Zhenguiai) that are widely used for processing noodles. Results showed that the cooked break rate and the cooking loss rate of rice noodles processed from grains of the ratoon crop were similar to those of the main crop in both cultivars; however, changes in texture of cooked rice noodles processed from grains of the ratoon crop compared with the main crop were cultivar-dependent, being significantly softer in Zhenguiai but not in Guichao 2. Hardness and chewiness of cooked rice noodles were significantly negatively correlated with amylopectin content in milled rice grains in Zhenguiai, indicating that amylopectin content is a key chemical property determining the texture differences between rice noodles processed from grains of ratoon and main crops.

Evidence and Impacts of Nanoplastic Accumulation on Crop Grains.

Nanoplastics are emerging pollutants of global concern. Agricultural soil is becoming a primary sink for nanoplastics generated from plastic debris. The uptake and accumulation of nanoplastics by crops contaminate the food chain and pose unexpected risks to human health. However, whether nanoplastics can enter grains and their impact on the grains of crop grown in contaminated soil is still unknown. Here, the translocation of polystyrene nanoplastics (PS-NPs) in crops, including peanut (Arachis hypogaea L.) and rice (Oryza sativa L.) is investigated. It is demonstrated PS-NPs translocation from the root and accumulation in the grains at the maturation stage. The treatment with PS-NPs (250 mg kg-1 ) increases the empty-shell numbers of rice grain by 35.45%, thereby decreasing the seed-setting rate of rice by 3.02%, and also decreases the average seed weight of peanuts by 3.45%. Moreover, PS-NPs exerted adverse effects on nutritional quality, such as decreasing the content of mineral elements, amino acids, and unsaturated fatty acids. To the knowledge, this is the first report of the presence of nanoplastics in the grains of crop plants grown in soil containing nanoplastics, and the results highlight the impact of nanoplastics on the yield and nutritional quality of crop grains.

Biochar Effects Coastal Saline Soil and Improves Crop Yields in a Maize-Barley Rotation System in the Tidal Flat Reclamation Zone, China

The summer maize-winter barley (or wheat) rotation system is a conventional farming method in coastal areas of east China. However, researchers have paid little attention to the increasing soil degradation after successive crop rotation in coastal saline agriculture. In the current study, a two-year field experiment was conducted to investigate the changes in soil physio-chemical properties and crop grain yields under the maize-barley rotation system. Wheat straw derived biochar (BC) was applied to topsoil (0~20 cm) at four different rates (0, 7.5, 15 and 30 Mg ha−1) before summer maize cultivation, and no biochar was added in the cultivation of the winter barley. Bulk density (BD), water holding capacity (WHC), water stable aggregate (WSA), soil electrical conductivity (EC), pH (1:5 water w/v) and soil organic carbon (SOC), at the harvesting time of maize and barley, were analyzed. The application of biochar increased WHC and macro-aggregate (>2 mm) content after barley harvest. Soil EC was mainly affected by the rain during maize cultivation and increased only slightly under BC treatments. However, no difference in EC was found among all treatments after barley harvest. The application of BC at 30 Mg ha−1 increased the maize yield by 66% but produced no difference in the barley yield. We concluded that biochar could be an effective option to mitigate soil degradation and improve crop productivity in coastal saline agriculture.

Balanced composition of multicomponent groats in conditions of the adequate nutrition concept

The concept of adequate nutrition envisages the compliance of a diet or a multicomponent product with multiple specific criteria, including the balance of proteins, fats and carbohydrates (P: F: C), biological value of protein, the presence of necessary vitamins and minerals in the composition and so on. Adherence to the theory of adequate nutrition is a multicriterion task, which solution in the full measure is not considered possible. The paper examines specific indicators and makes an attempt to construct multicomponent groats that meet two main criteria — protein completeness and balance (P: C). The value of the criteria is based on the recommendations of the Federal Hygienic and Epidemiological Center of the RF. Complete protein corresponds to the minimal essential amino acid (EAA) score not lower than one. The B: C ratio, in general, depends on a human gender, age and physical load. The B: C was taken as averaged for men of different ages and different physical loads. In this study, traditional groats (fine-ground barley, rice, maize, millet), groats from grains of leguminous crops (chickpea, lentil, kidney bean, pea) and oil seeds (flax, hemp) were examined as ingredients. Using the computational method and data on the nutritional value of food products from several databases, the authors developed recipes of two- and threecomponent groats that meet the indicated criteria. The proportion of leguminous and oil crops in the obtained mixtures is 17–45%, which can affect taste of porridge. During the study, tasting of fine-ground barley porridge with addition of chickpea and lentil upon legume addition at a level of 10–35% was carried out. The porridge taste remained to be pleasant even at the maximum level of legume addition. Off-flavor typical of legumes was absent.

Probability of cultivating Se-rich maize in Se-poor farmland based on intensive field sampling and artificial neural network modelling

Selenium (Se) is a necessary micronutrient for humans, and its supplementation from crop grains is important to address the ubiquitous Se deficiency in people worldwide. Se uptake by crops largely depend on soil bioavailable Se rather than soil total Se content, which provides possibilities to explore the Se-rich crops in Se-poor area. Here, the possibility of cultivating Se-rich maize grains in Se-poor farmland was tested based on intensive field sampling and mathematical modelling. Sampling was conducted at county scale, and a total of 7779 topsoil samples and 109 maize samples with paired rhizosphere soils samples were collected. Results showed that although the soil Se content in the study county from southwestern China was at a low level (0.01–2.75 mg kg−1), 54.1% of the maize grain samples satisfied the standard for Se-rich products (0.02–0.30 mg kg−1). Soil organic matter, iron oxide, and phosphorus levels were correlated negatively with Se bioconcentration factor (BCF) of maize grain. Compared with the multivariate linear regression model, the artificial neural network (ANN) model was more accurate and reliable in predicting maize Se BCF. Prediction using the ANN model showed that 22.7% of the county's farmland was suitable for cultivating naturally Se-rich maize, which increased 21.3% growing areas than that from cultivation based on simply soil total Se. This study provided a new methodological framework for natural Se-rich maize production and verified the probability of cultivating naturally Se-rich maize in Se-poor farmland.

Анализ сошников зерновых сеялок

The article presents an analysis of the working bodies of grain seeders: double-disk, single-disk, anchor. The advantages and disadvantages of the presented working bodies are described. A model of a double-disk coulter with axes displacement in the direction of travel and a decrease in the angle of disc set-up from (10° to 7°) is proposed. The results of laboratory tests are presented, which indicate the advantage of the proposed opener model over the prototype. Keywords: SEEDER, SHEETER, SEEDING UNIT, GRAIN CROPS, AGRICULTURAL REQUIREMENTS, SHEETER MODERNIZATION, ROW SEEDING

Legumes can increase the yield of subsequent wheat with or without grain harvesting compared to Gramineae crops: A meta-analysis

Legumecereal crop rotation is considered a sustainable intensive rotation model that can reduce nitrogen (N) inputs, improve soil quality, increase biodiversity and reduce environmental pollution risks. However, compared with Gramineaecereal rotations, quantitative assessment of the effects of legumecereal rotations on grain yield and N use of subsequent cereal crops are lacking. There is also no comprehensive analysis of factors explaining the change in yield effects of subsequent cereal crops, or the differences in these effects, depending on whether the grains of the legume crops are harvested. Here, a meta-analysis of the effects of legumewheat (LW) and Gramineaewheat (GW) rotations on wheat yield and N use was conducted based on 453 observations from 62 studies published worldwide. Our results suggested that compared with GW rotations, LW rotations had a positive effect on wheat yields. Wheat yield was significantly increased by 21.28 % and 31.71 % (P < 0.05) under legume-harvested grainwheat (LHGW) rotation and legume that non-harvested grainwheat (LNHGW) rotation systems, respectively. The positive benefits of legume crops on wheat yield were reduced to some extent by their harvest. The main factors affecting wheat yield were fertilization rates and climate and soil types, with weight ratios of 0.32, 0.21 and 0.16, respectively. For fertilization rates, wheat yield benefits decreased with increases in N fertilizer inputs, and we identified significant positive benefits in temperate, subtropical and Mediterranean climates (P < 0.05). For soil types, sandy and loamy sand soils with low clay contents generally had the best wheat yield benefits. Furthermore, compared with GW rotations, LW rotations increased N use efficiency by 8.57 % on average, which was significantly affected by N inputs (P < 0.05). Therefore, the introduction of legume crops into the GW rotation system can increase wheat yields and reduce N applications regardless of whether legume grains are harvested. Moreover, legume crops have the best wheat yield benefits under low N input conditions, which can make an important contribution to the sustainable intensification of global wheat production.

Reductions in soil water nitrate beneath a perennial grain crop compared to an annual crop rotation on sandy soil

Nitrate (NO3--N) leaching into groundwater as a result of high nitrogen (N) fertilizer rates to annual crops presents human health risks and high costs associated with water treatment. Leaching is a particularly serious concern on sandy soils overlying porous bedrock. Intermediate wheatgrass (IWG) [Thinopyrum intermedium (Host.) Barkw. &amp;amp; D.R. Dewey], is a perennial grass that is being bred to produce agronomically and economically viable grain, which is commercially available as Kernza®. Intermediate wheatgrass is a low-input crop has the potential to produce profitable grain and biomass yields while reducing NO3--N leaching on sandy soils compared with common annual row crop rotations in the Upper Midwest. We compared grain yields, biomass yields, soil solution NO3--N concentration, soil extractable NO3--N, soil water content, and root biomass under IWG and a conventionally managed corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotation for 3 years on a Verndale sandy loam in Central Minnesota. Mean soil solution NO3--N was 77–96% lower under IWG than the annual crop rotation. Soil water content was greater under annuals compared to IWG early in the growing season, suggesting greater water use by IWG during this time. Interactions between crop treatments and depth were observed for soil water content in Year 3. Root biomass from 0 to 60 cm below the soil surface was five times greater beneath IWG compared to soybean, which may explain differences in soil extractable and solution NO3--N among crops. With irrigation on coarse structured soils, IWG grain yields were 854, 434, and 222 kg ha−1 for Years 1–3 and vegetative biomass averaged 4.65 Mg ha−1 yr−1; comparable to other reports on heavier soils in the region. Annual crop grain yields were consistent with local averages. These results confirm that IWG effectively reduces soil solution NO3--N concentrations even on sandy soils, supporting its potential for broader adoption on land vulnerable to NO3--N leaching.

Research on a rapid identification method for counting universal grain crops.

Thousand-grain weight is a key indicator of crop yield and an important parameter for evaluating cultivation measures. Existing methods based on image analysis are convenient but lack a counting algorithm that is suitable for multiple types of grains. This research develops an application program based on an Android device to quickly calculate the number of grains. We explore the short axis measurement method of the grains with morphological thought, and determine the relationship between the general corrosion threshold and the short axis. To solve the problem of calculating the number of grains in the connected area, the study proposes a corrosion algorithm based on the short axis and an improved corner point method. After testing a variety of crop grains and equipment, it was found that the method has high universality, supports grain counting with white paper as the background, and has high accuracy and calculation efficiency. The average accuracy rate is 97.9%, and the average time is less than 0.7 seconds. In addition, the difference between the average accuracy for various mobile phones and multiple crops is small. This research proposes a grain counting algorithm with a wide range of applications to meet the requirements of nonglare use in the field. The algorithm provides a fast, accurate, low-cost tool for counting grains of wheat, corn, mung bean, soybean, peanut, rapeseed, etc., which is less constrained by space and power conditions. The algorithm is highly adaptable and can provide a reference for the study of grain counting.

Contribution of tillers to maize yield stability at low plant density

AbstractOne of the main challenges of using low plant densities in restrictive and variable environments is to maximize the use of resources in better‐than‐expected years. In this context, tillering could be an alternative to increase reproductive and vegetative plasticity. The objectives of this study were to (a) characterize the correlation between environmental conditions, tiller traits, crop grain yield, and grain yield advantages due to tillers; (b) determine the grain yield response to tillering (i.e., grain yield difference between tillered and nontillered crops) for a wide range of environments; and (c) to evaluate the effect of tiller presence on grain yield of the main shoot, considering its effect on the apical and subapical ears. Tillered and nontillered crops were evaluated under rainfed conditions during two seasons (2018–2019 and 2019–2020). These experiments were carried out at 11 sites in the southern Argentinean Pampas, varying sowing date (22 Oct. to 5 Dec.), plant density (2–3 plants m−2), genotype (AX7784 and AX7761), and soil depth. Grain yield (3.2–11.9 Mg ha−1) was correlated with tillers productivity, mainly explained by postflowering precipitations. The contribution of tillers to grain yield was more proportional than their consequent yield depression at the main shoot. Tillers either increased (3 sites) or maintained (8 sites) grain yield, and their contribution increased as the environment improved without any detrimental effect in the most restrictive environments. Tillering has the potential for increasing resource (radiation, water, nitrogen) use efficiency under low plant density strategies adopted for restrictive environments.

Stacking herbicide detoxification and resistant genes improves glyphosate tolerance and reduces phytotoxicity in tobacco (Nicotiana tabacum L.) and rice (Oryza sativa L.)

Glyphosate residues retained in the growing meristematic tissues or in grains of glyphosate-resistant crops affect the plants physiological functions and crop yield. Removing glyphosate residues in the plants is desirable with no penalty on crop yield and quality. We report a new combination of scientific strategy to detoxify glyphosate that reduces the residual levels and improve crop resistance. The glyphosate detoxifying enzymes Aldo-keto reductase (AKR1) and mutated glycine oxidase (mGO) with different modes of action were co-expressed with modified EPSPS, which is insensitive to glyphosate in tobacco (Nicotiana tabacum L.) and rice (Oryza sativa L.). The transgenic tobacco plants expressing individual PsAKR1, mGO, CP4-EPSPS, combinations of PsAKR1:CP4EPSPS, PsAKR1:mGO, and multigene with PsAKR1: mGO: CP4EPSPS genes were developed. The bio-efficacy studies of in-vitro leaf regeneration on different concentrations of glyphosate, seedling bioassay, and spray on transgenic tobacco plants demonstrate that glyphosate detoxification with enhanced resistance. Comparative analysis of the transgenic tobacco plants reveals that double and multigene expressing transgenics had reduced accumulation of shikimic acid, glyphosate, and its primary residue AMPA, and increased levels of sarcosine were observed in all PsAKR1 expressing transgenics. The multigene expressing rice transgenics showed improved glyphosate resistance with yield maintenance. In summary, results suggest that stacking genes with two different detoxification mechanisms and insensitive EPSPS is a potential approach for developing glyphosate-resistant plants with less residual content.

Evaluating Strip and No-Till Maintenance of Perennial Groundcovers for Annual Grain Production

Perennial groundcover (PGC) merges scalable soil and water conservation with high-yielding row crops, enhancing ecosystem services of annual grain crop production. However, ineffective groundcover suppression increases competition between the groundcover and row crop, reducing row crop grain yield. The objective of this study was to assess the effectiveness of three Kentucky bluegrass (KBG) groundcover suppression methods each at narrow and wide widths on maize (Zea mays L.) growth and development in evenly spaced PGC, compared to alternating PGC swards and a no-PGC conventional tillage control. Suppression methods for evenly spaced PGC included two different strip tillage implements, completing either shallow or deep soil fracture, for mechanical suppression and a banded sprayer for no-tillage chemical suppression. We measured weekly for maize plant height, phenological stage of development, reflected red:far-red (R:FR) ratio, early vegetative and final plant density, grain and stover yield, yield components of kernel rows ear−1, kernels row−1, kernels ear−1, ear length, kernel weight, grass frequency, and weed community. In 2020, maize grain yield in the alternating PGC swards (11.38 Mg ha−1) was similar to the control (12.78 Mg ha−1) and greater than in the evenly spaced groundcover (9.62 Mg ha−1). Maize grain yield was similar for systems in 2021 (7.41 Mg ha−1), due to drought and high coefficient of variation. Weed community was similar for systems in both years. A maize competition response was observed for both suppression widths across methods. Groundcover dormancy may be needed in conjunction with effective chemical and/or mechanical groundcover suppression to support maize production in PGC.

Maize prolificacy under contrasting plant densities and N supplies: I. Plant growth, biomass allocation and development of apical and sub-apical ears from floral induction to silking

In limited-production regions for maize (Zea mays, L.) crop, late sowing date and low plant densities are progressively adopted. At low plant densities, the expression of prolificacy (i.e., more than one fertile ear per plant) can stabilize maize yield throughout environments. However, the limited adoption of N fertilization can reduce kernel set on the apical (E1) and sub-apical ear (E2) and consequently crop grain yield at low plant densities. Five Argentinian maize hybrids with different degrees of prolificacy (1.37–1.92 ears pl-1 at 4 pl m-2 irrigated and without N limitations) were cultivated under contrasting plant densities (4 and 8 pl m-2) and N fertilization rates (70 and 270 kg N ha-1) to analyze (i) plant biomass, biomass allocation in E1 and E2 (BAE1 and BAE2), and floret differentiation of both ears from floral induction to silking stage, (ii) the anthesis-silking intervals of E1 and E2 (ASIE1 and ASIE2) and the silking interval between E1 and E2 (ESI), and (iii) silk extrusion of both ears. From the eight-ligulated leaf stage onwards, low N availability and high density decreased plant biomass and BAE2 without modifying BAE1. Additionally, N stress reduced floret differentiation of E2 in the less prolific hybrids (DK-747 and DK-7210). On the contrary, E1 and E2 of the most prolific hybrids (DK-3F22, DK-4F37 and DK-664) showed similar temporal patterns of growth and floret differentiation. These hybrids presented the highest proportion of exposed silks in both ears coinciding with their highest BAE1 and BAE2, which possibly modulated silk elongation. Finally, under the most stressful environments, the lower BAE2 than BAE1 at silking increased ASI of both ears, ESI and reduced the proportion of plants with silks of E2 exposed to pollen. The latter response (i.e., low proportion of plants with silks extrusion in E2) was more pronounced in less prolific hybrids. Therefore, floret differentiation and BA in E2 of the most prolific hybrids would be more stable in the face of changes in nutritional offer, a prevalent scenario of limited-production regions.