Important Cereals Research Articles

Pre- and post-harvest aflatoxin contamination and management strategies of Aspergillus spoilage in East African Community maize: review of etiology and climatic susceptibility.

Globally, maize (Zea mays L.) is deemed an important cereal that serves as a staple food and feed for humans and animals, respectively. Across the East African Community, maize is the staple food responsible for providing over one-third of calories in diets. Ideally, stored maize functions as man-made grain ecosystems, with nutritive quality changes influenced predominantly by chemical, biological, and physical factors. Food spoilage and fungal contamination are convergent reasons that contribute to the exacerbation of mycotoxins prevalence, particularly when storage conditions have deteriorated. In Kenya, aflatoxins are known to be endemic with the 2004 acute aflatoxicosis outbreak being described as one of the most ravaging epidemics in the history of human mycotoxin poisoning. In Tanzania, the worst aflatoxin outbreak occurred in 2016 with case fatalities reaching 50%. Similar cases of aflatoxicoses have also been reported in Uganda, scenarios that depict the severity of mycotoxin contamination across this region. Rwanda, Burundi, and South Sudan seemingly have minimal occurrences and fatalities of aflatoxicoses and aflatoxin contamination. Low diet diversity tends to aggravate human exposure to aflatoxins since maize, as a dietetic staple, is highly aflatoxin-prone. In light of this, it becomes imperative to formulate and develop workable control frameworks that can be embraced in minimizing aflatoxin contamination throughout the food chain. This review evaluates the scope and magnitude of aflatoxin contamination in post-harvest maize and climate susceptibility within an East African Community context. The paper also treats the potential green control strategies against Aspergillus spoilage including biocontrol-prophylactic handling for better and durable maize production.

FREQUENCY AND PATHOGENICITY OF Fusarium SPECIES IN WHEAT SPIKE: PRELIMINARY RESULTS

Wheat (Triticum aestivum) is a commercially important cereal in Mexico; however, there have been reports of head blight in Guanajuato, Mexico, which have been attributed to Fusarium species. This study hypothesized that wheat head blight is caused by several species of Fusarium. Therefore, the objective was to evaluate the frequency and pathogenicity of Fusarium species in wheat spike in the state of Guanajuato. For this purpose, plots sown with wheat in the 20 wheat-producing municipalities were sampled. The strains were isolated until pure cultures were obtained, and they were morphologically and molecularly characterized; the sequences obtained were registered in GenBank. The pathogenicity and severity of the disease were assessed on flowering wheat plants of the Cortázar S94 variety at the flowering stage. The results were evaluated 10 days after inoculation and the data were analyzed using ANOVA statistical analysis. Ten Fusarium species were found, with F. oxysporum (35.57 %), F. verticillioides (12.5 %), and F. proliferatum (11.53 %) being the most common. All Fusarium strains were pathogenic, with F. oxysporum being the most severe, followed by F. proliferatum. In conclusion, it was possible to identify the causal species of wheat head blight in the state of Guanajuato.

Increasing germination and antioxidant activity of aged wheat and triticale grains by priming with gamma-aminobutyric acid

During storage, elevated temperature and humidity cause accelerated aging and deterioration of seeds of various plant species, including important cultivated cereals, such as wheat and triticale. Germination of old seeds can be facilitated by seed priming with physiologically active substances that correct the pro/antioxidant balance and reduce the development of oxidative stress. Gamma-aminobutyric acid (GABA) is a regulatory compound with direct and indirect antioxidant effects. However, its effect on the germination of grains of cereals with low germination has not been extensively studied. The objective of this study was to examine the impact of GABA priming on the germination of aged grains of winter bread wheat (Triticum aestivum ‘Scorpion’) and winter triticale (×Triticosecale ‘Raritet’). the extent of oxidative stress and the state of the antioxidant system in seedlings. The results indicated that a three-hour treatment of grains with GABA at the optimal concentration (1 mM) resulted in a significant (18–21%) increase in germination energy and seed germination rate, as well as an increase in the biomass of shoots and roots of seedlings of both species. Concomitantly, the influence of GABA resulted in a reduction in oxidative stress markers, including the generation of superoxide anion radicals, hydrogen peroxide content, and the product of lipid peroxidation malondialdehyde. In wheat seedlings, the total content of phenolic compounds increased, while in triticale seedlings, the content of anthocyanins increased almost twofold. In seedlings derived from GABA-primed grains, catalase activity was also significantly elevated in the absence of notable alterations in superoxide dismutase and peroxidase activity. It was postulated that GABA priming is a promising approach for enhancing the germination of cereal seeds with diminished sowing quality.

Deciphering fungicide resistance in Phytophthora: mechanisms, prevalence, and sustainable management approaches.

The genus Phytophthora contains more than 100 plant pathogenic species that parasitize a wide range of plants, including economically important fruits, vegetables, cereals, and forest trees, causing significant losses. Global agriculture is seriously threatened by fungicide resistance in Phytophthora species, which makes it imperative to fully comprehend the mechanisms, frequency, and non-chemical management techniques related to resistance mutations. The mechanisms behind fungicide resistance, such as target-site mutations, efflux pump overexpression, overexpression of target genes and metabolic detoxification routes for fungicides routinely used against Phytophthora species, are thoroughly examined in this review. Additionally, it assesses the frequency of resistance mutations in various Phytophthora species and geographical areas, emphasizing the rise of strains that are resistant to multiple drugs. The effectiveness of non-chemical management techniques, including biological control, host resistance, integrated pest management plans, and cultural practices, in reducing fungicide resistance is also thoroughly evaluated. The study provides important insights for future research and the development of sustainable disease management strategies to counter fungicide resistance in Phytophthora species by synthesizing current information and identifying knowledge gaps.

Wheat Cybrid Plants, OryzaWheat, Regenerated from Wheat-Rice Hybrid Zygotes via in Vitro Fertilization System Possess Wheat-Rice Hybrid Mitochondria.

Hybridization generates biodiversity, and wide hybridization plays a pivotal role in enhancing and broadening the useful attributes of crops. The hybridization barrier between wheat and rice, the two most important cereals, was recently overcome by in vitro production of allopolyploid wheat-rice hybrid zygotes, which can develop and grow into mature plants. In the study, genomic sequences and compositions of the possible hybrid plants were investigated through short- and long-read sequencing analyses and fluorescence in situ hybridization (FISH)-based visualization. The possible hybrid possessed whole wheat nuclear and cytoplasmic DNAs and rice mitochondrial (mt) DNA, along with variable retention rates of rice mtDNA ranging from 11% to 47%. The rice mtDNA retained in the wheat cybrid, termed Oryzawheat, can be transmitted across generations. In addition to mitochondrial hybridization, translocation of rice chromosome 1 into wheat chromosome 6A was detected in a F1 hybrid individual. OryzaWheat can provide a new horizon for utilizing inter-subfamily genetic resources among wheat and rice belonging to different subfamilies, Pooideae and Ehrhartoideae, respectively.

Occurrence of aflatoxins in organic rice produced and commercialized in Brazil

Since rice is one of the most important cereals for the human diet worldwide, and its organic production has increased over the last years, the objective of this study was to evaluate the occurrence of aflatoxins in samples of organic rice produced and sold in Brazil, and to determine the average probable daily intake (APDI) of aflatoxins due to the consumption of organic rice. Sixty samples were analyzed for aflatoxins B1, B2, G1, and G2 using high-performance liquid chromatography (HPLC). Results demonstrated that 8.3% of brown rice samples showed levels from 0.13 to 1.24 μg/kg considering the sum of aflatoxins B1, B2, G1, and G2, while one sample (8.33%) of polished rice and one sample (33.34%) of red rice presented levels of 0.11 μg/kg and 0.16 μg/kg for AFB1 and AFG2, respectively. According to the Factor Analysis of Mixed Data (FAMD), AFB1 and AFG1 had the highest occurrence in samples, and the rice type was the qualitative variable with the greatest intensity, showing that the rice manufacturing process can influence the levels of aflatoxins found in grains. The APDI value was 0.004 μg/kg b.w./day for the sum of aflatoxins B1, B2, G1, and G2, indicating that daily consumption of contaminated rice may pose a risk of hepatocarcinogenicity. Although the concentrations of aflatoxins found in the present study did not exceed the maximum tolerable limit recommended by Brazilian regulations (5 μg/kg for cereals), additional studies are necessary to obtain a vast database for the occurrence of aflatoxins in organic rice and, thus, to establish new tolerable limits avoiding risks for consumer health.

Role of ten different exogenous plant growth promoters in regulating cytotoxic and genotoxic processes in barley exposed to high temperature stress

Agricultural crop affected preliminary and the most prominent by the adverse effects of global climate change have to adapt to various abiotic factors that will occur as a result of climate fluctuations in the near-future and struggle to survive. Among abiotic factors, the one of the greatest impact on plant stress is high temperature. Therefore, the most important step to take action against the global threat is the development of new temperature tolerant varieties. Barley, which is the fourth most important cereal in the world after wheat, maize, and rice are affected by high ambient temperatures. In this work, the effects of their alone and in double, triple combinations of ten various plant growth regulators (PGRs) on mitotic activity and chromosome behaviors in root meristems of barley exposed to high temperature (30°C) were investigated. In the experiments, Hordeum vulgare L. cv. Bülbül 89 variety and GA3, KIN, BA, E, EBR, TRIA and PAs (Spm, Spd, Put, Cad) as growth regulators were used. The results obtained were compared with each other and with those of the seeds germinated at optimum temperature (20°C). Consequently; it has been determined that most of the PGRs studied, especially the GA3 and their combinations with GA3, exhibit a very successful performance on mitotic activity and cytogenetic aberrations in barley seeds germinated under high temperature stress- HTS conditions. The effects of these PGRs (except for EBR) and their combinations on mitotic activity and chromosome behaviors under HTS have been presented in this study for the first time.

Protein research in millets: current status and way forward.

Millets' protein studies are lagging behind those of major cereals. Current status and future insights into the investigation of millet proteins are discussed. Millets are important small-seeded cereals majorly grown and consumed by people in Asia and Africa and are considered crops of future food security. Although millets possess excellent climate resilience and nutrient supplementation properties, their research advancements have been lagging behind major cereals. Although considerable genomic resources have been developed in recent years, research on millet proteins and proteomes is currently limited, highlighting a need for further investigation in this area. This review provides the current status of protein research in millets and provides insights to understand protein responses for climate resilience and nutrient supplementation in millets. The reference proteome data is available for sorghum, foxtail millet, and proso millet to date; other millets, such as pearl millet, finger millet, barnyard millet, kodo millet, tef, and browntop millet, do not have any reference proteome data. Many studies were reported on stress-responsive protein identification in foxtail millet, with most studies on the identification of proteins under drought-stress conditions. Pearl millet has a few reports on protein identification under drought and saline stress. Finger millet is the only other millet to have a report on stress-responsive (drought) protein identification in the leaf. For protein localization studies, foxtail millet has a few reports. Sorghum has the highest number of 40 experimentally proven crystal structures, and other millets have fewer or no experimentally proven structures. Further proteomics studies will help dissect the specific proteins involved in climate resilience and nutrient supplementation and aid in breeding better crops to conserve food security.

Genetic Biofortification of Winter Wheat with Selenium (Se).

Wheat is one of the three most important cereals in the world, along with rice and maize. It serves as the primary food and source of energy for about 30-40% of the world's population. However, the low levels of micronutrients in wheat grains can lead to deficiencies of those micronutrients in people whose dietary habits are mostly based on cereals such as wheat. Apart from iron (Fe) and zinc (Zn), a lack of selenium (Se) is also one of the biggest problems in the world. The essentiality of Se has been confirmed for all animals and humans, and the lack of this micronutrient can cause serious health issues. Wheat dominates the world's cereal production, so it is one of the best plants for biofortification. Due to the fact that agronomic biofortification is not an economical or environmentally acceptable approach, genetic improvement of cereals such as wheat for the enhanced content of micronutrients in the grain represents the most efficient biofortification approach.

Yield prediction models for some wheat varieties with satellite‐based drought indices and machine learning algorithms

AbstractIn recent years, frequent drought events in Konya, one of Türkiye's most important cereal production centres, have led to increased pressure on water and soil resources, resulting in yield losses, particularly in wheat production. Alternative yield prediction models, especially those that play a crucial role in agricultural import–export planning in the region, are important for economic contributions and the development of early warning systems. In this context, the aim of this study is to develop models that can be used in the yield prediction of wheat varieties widely grown in the Konya Altınova region. Agricultural drought indices obtained from Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) products of the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) satellite were used to obtain model inputs. These indices are the Vegetation Condition Index (VCI), Temperature Condition Index (TCI), Vegetation Health Index (VHI) and Vegetation Supply Water Index (VSWI). In obtaining the input parameters for the models, the growth periods of the varieties in the region were also considered. Using various machine learning algorithms, 21 yield prediction models for Bayraktar‐2000, 12 for Kızıltan‐91 and 8 for Bezostaya‐1 were presented as alternatives, with model performances (coefficient of determination, R2) ranging between 0.74 and 0.97, 0.73 and 0.96, and 0.69 and 0.87, respectively.

Integrated management of yellow aphid (Melanaphis sacchari Zehntner) in sorghum (Sorghum bicolor L.) Moench in Guerrero, Mexico

Sorghum is cultivated in tropical and subtropical regions of the world and is an important cereal for Mexico. However, it is affected by different pests, especially the yellow aphid. The objective of the research was to evaluate the effectiveness of biological, botanical and chemical insecticides in reducing Melanaphis sacchari populations in sorghum plants under greenhouse conditions. Planting was conducted in a greenhouse, using the sorghum hybrid 945-M. Pests, diseases and weeds management were implemented. The incidence of the yellow aphid was induced artificially. A total of 13 treatments were applied. The following variables were assessed: the number of aphids per leaf, the biological effectiveness of the treatments, plant height, diameter of the plant stem, number of leaves, and the weight of fresh and dry plants. An analysis of variance was conducted for each variable under study, as along with a comparison of means using the Tukey method (α=0.05) and correlation analysis using the SAS® 9.4 software. The chemical, biological and organic insecticide that exhibited the greatest control of the yellow aphid (more than 95%) were: Toretto® (sulfoxaflor), PHC® Meta Tron® (M. anisopliae), Bio-Die® (Argemonin, Berberine, Ricinin and a-Terthienyl). Adequate management strategies are needed to avoid health problems in people, environmental contamination and resistance or multiple resistance.

Evaluation of Anti-Inflammatory Activity in Methanolic Seed Extracts of International Sorghum bicolor L. Resources

Sorghum is an important cereal with high value as a health food ingredient because it contains various phenolic compounds. Anti-inflammatory activity was assessed using 12 sorghum resources collected from various countries to explore their potential as medicinal resources. The findings revealed that, at extract concentrations of 25 µg/mL and 50 µg/mL, cell survival rates were observed to be between 70 and 80% for most varieties, with the exception of K159081. In the analysis of anti-inflammatory activity, measured by the rate of nitric oxide (NO) production, sorghum varieties K159041 and K159081 exhibited NO production rates of 0.46 ± 0.38% and 2.58 ± 0.20%, respectively, indicating significant anti-inflammatory properties. The investigation into anti-inflammatory effects also included examining the expression of the inducible nitric oxide synthase (iNOS) gene, which is related to the inflammatory response triggered by LPS in macrophages. Varieties K159041, K159048, K159077, K159078, K159081, K159089, and K159096 were analyzed for this purpose. Further, an expression test of the cyclooxygenase 2 (COX-2) gene revealed values less than 0.4 in K159077, K159081, and K159089, suggesting these sorghum lines possess higher anti-inflammatory activity compared to others. Additionally, the expression analysis of tumor necrosis factor alpha (TNF-α), a gene identified as an inflammatory cytokine, showed that the mRNA levels in the lines K159048, K159077, K159078, K159088, K159089, K159093, and K159096 were expressed at lower levels relative to other sorghum resources, categorizing them as having high anti-inflammatory activity. Notably, the K159081 line exhibited the lowest expression level of all genes associated with inflammation, marking it as a valuable medicinal resource with potential development as an anti-inflammatory agent.

Genetic structure analyses reveal multiple origins of Elymus sensu stricto (Poaceae)

AbstractElymus sensu stricto includes tetraploid species in the tribe Triticeae with a StH genome combination derived from Hordeum (H) and Pseudoroegneria (St). The group is related to many important cereals and forage grasses and is considered an important wild genetic resource for crop breeding. The relationships within Elymus s.s. have been difficult to resolve due to the large number of widely distributed species, a high degree of morphological diversity, introgression between species, and potential multiple origins. Using genome-wide DArTseqLD data from 57 taxa, including the StH group and associated species, it is possible to gain representative information about the genetic structure of the genus. SplitsTree, STRUCTURE and principal component analysis (PCoA) show that Elymus s.s. is divided into two major clades highly correlating with geographical origin separating American species from Eurasians. These findings, together with the contribution of different Pseudoroegneria and Hordeum species to the two clades, support the conclusion that Elymus s.s. has at least two independent origins. The Eurasian and American clades are further divided into three and two subclades, respectively. The results show that Elymus species have migrated multiple times from North to South America and between America and Eurasia. The new findings could be used to develop a new classification of Elymus s.s. with sections based on phylogenetic data.

Greenhouse gas and ammonia emissions in modelled cereal crop production under Polish agricultural conditions: An example spring barley

Based on the analysis of statistical data, the average area under cultivation and average yields of barley in Poland in 2010–2020 were calculated. Barley is one of the most important cereals grown in Poland. Its cultivation area occupied an average of 920,595 ha in these years, with average yields of 3.66 Mg∙ha−1. Barley is a cereal grown mainly as a spring cereal. The average area under spring species in these years accounted for 95% (875,771 ha) of the total area under this cereal, and the average yield of spring varieties was 3.60 Mg∙ha−1. In order to estimate emissions of greenhouse gases (GHG) and ammonia (NH3), the sources of emissions – inorganic fertilisers, fuel consumption – were analysed for selected barley cultivation technologies, differentiated by yield level, and variant model production technologies were developed to obtain projected yields. Emissions were calculated for individual greenhouse gases (N2O, CH4 and CO2) and they were recalculated according to the greenhouse potential of each gas (GWP – global warming potential) to be able to compare the total amount of greenhouse gas emissions for the analysed variants. Greenhouse gas emissions for cultivation technology ranged from 134.53 to 136.48 kg CO2eq for 1 Mg yield. A more accurate Tier 2 method was used to estimate NH3 emissions, taking into account soil conditions and climate zone. The estimated ammonia emissions from the application of mineral fertilisers were from 0.99 kg to 2.35 kg for 1 Mg yield.

Entomofauna Associated with Corn Cultivation and Damage Caused by Some Pests According to the Planting Season on the Ecuadorian Coast

Corn (Zea mays L.) is an important cereal for food sovereignty, extensively planted due to its adaptation to various agroecological conditions. Climatic conditions and pests can affect its production. Concerning the latter, natural enemies could be considered in biological control programs. The objective of this study was to estimate the influence of the presence of insects, damage to plants and cobs, and their incidence on corn yield in two planting seasons. During the rainy (February to May) and dry seasons (Jun to October) of the year 2023, in Calceta, Lodana, and Quevedo, three important corn-growing areas on the Ecuadorian coast, corn plots of 1126 m2 were planted. The diversity of phytophagous and natural enemies was estimated. Damage to young plants and cobs was observed, and corn yield was determined. Of the 9073 insects observed, 44.2% and 55.8% constituted phytophagous and natural enemies, respectively. A moderate diversity (Shannon-H Index = 2.474–2.629 and Margalef Index = 2.734–3.110) of insects associated with corn was determined. Yield (range: 6.9 to 15.3 t) was negatively correlated with rainfall and cob damage (p < 0.05). Although precipitation is necessary for planting in rainy season, frequent and intense rains could be affect corn yield.

Mapping Maize Planting Densities Using Unmanned Aerial Vehicles, Multispectral Remote Sensing, and Deep Learning Technology

Maize is a globally important cereal and fodder crop. Accurate monitoring of maize planting densities is vital for informed decision-making by agricultural managers. Compared to traditional manual methods for collecting crop trait parameters, approaches using unmanned aerial vehicle (UAV) remote sensing can enhance the efficiency, minimize personnel costs and biases, and, more importantly, rapidly provide density maps of maize fields. This study involved the following steps: (1) Two UAV remote sensing-based methods were developed for monitoring maize planting densities. These methods are based on (a) ultrahigh-definition imagery combined with object detection (UHDI-OD) and (b) multispectral remote sensing combined with machine learning (Multi-ML) for the monitoring of maize planting densities. (2) The maize planting density measurements, UAV ultrahigh-definition imagery, and multispectral imagery collection were implemented at a maize breeding trial site. Experimental testing and validation were conducted using the proposed maize planting density monitoring methods. (3) An in-depth analysis of the applicability and limitations of both methods was conducted to explore the advantages and disadvantages of the two estimation models. The study revealed the following findings: (1) UHDI-OD can provide highly accurate estimation results for maize densities (R2 = 0.99, RMSE = 0.09 plants/m2). (2) Multi-ML provides accurate maize density estimation results by combining remote sensing vegetation indices (VIs) and gray-level co-occurrence matrix (GLCM) texture features (R2 = 0.76, RMSE = 0.67 plants/m2). (3) UHDI-OD exhibits a high sensitivity to image resolution, making it unsuitable for use with UAV remote sensing images with pixel sizes greater than 2 cm. In contrast, Multi-ML is insensitive to image resolution and the model accuracy gradually decreases as the resolution decreases.

The soil microbiome modulates the sorghum root metabolome and cellular traits with a concomitant reduction of Striga infection

Sorghum bicolor is among the most important cereals globally and a staple crop for smallholder farmers in sub-Saharan Africa. Approximately 20% of sorghum yield is lost annually in Africa due to infestation with the root parasitic weed Striga hermonthica. Existing Striga management strategies are not singularly effective and integrated approaches are needed. Here, we demonstrate the functional potential of the soil microbiome to suppress Striga infection in sorghum. We associate this suppression with microbiome-mediated induction of root endodermal suberization and aerenchyma formation and with depletion of haustorium-inducing factors, compounds required for the initial stages of Striga infection. We further identify specific bacterial taxa that trigger the observed Striga-suppressive traits. Collectively, our study describes the importance of the soil microbiome in the early stages of root infection by Striga and pinpoints mechanisms of Striga suppression. These findings open avenues to broaden the effectiveness of integrated Striga management practices.

Genetic Diversity and Population Structure of Maize (Zea mays L.) Inbred Lines in Association with Phenotypic and Grain Qualitative Traits Using SSR Genotyping

Maize (Zea mays L.) is an important cereal and is affected by climate change. Therefore, the production of climate-smart maize is urgently needed by preserving diverse genetic backgrounds through the exploration of their genetic diversity. To achieve this, 96 maize inbred lines were used to screen for phenotypic yield-associated traits and grain quality parameters. These traits were studied across two different environments (Anand and Godhra) and polymorphic simple sequence repeat (SSR) markers were employed to investigate the genetic diversity, population structure, and trait-linked association. Genotype–environment interaction (GEI) reveals that most of the phenotypic traits were governed by the genotype itself across the environments, except for plant and ear height, which largely interact with the environment. The genotypic correlation was found to be positive and significant among protein, lysine and tryptophan content. Similarly, yield-attributing traits like ear girth, kernel rows ear−1, kernels row−1 and number of kernels ear−1 were strongly correlated to each other. Pair-wise genetic distance ranged from 0.0983 (1820194/T1 and 1820192/4-20) to 0.7377 (IGI-1101 and 1820168/T1). The SSRs can discriminate the maize population into three distinct groups and shortlisted two genotypes (IGI-1101 and 1820168/T1) as highly diverse lines. Out of the studied 136 SSRs, 61 were polymorphic to amplify a total of 131 alleles (2–3 per loci) with 0.46 average gene diversity. The Polymorphism Information Content (PIC) ranged from 0.24 (umc1578) to 0.58 (umc2252). Similarly, population structure analysis revealed three distinct groups with 19.79% admixture among the genotypes. Genome-wide scanning through a mixed linear model identifies the stable association of the markers umc2038, umc2050 and umc2296 with protein, umc2296 and umc2252 with tryptophan, and umc1535 and umc1303 with total soluble sugar. The obtained maize lines and SSRs can be utilized in future maize breeding programs in relation to other trait characterizations, developments, and subsequent molecular breeding performances for trait introgression into elite genotypes.

Development of a Detection System for Types of Weeds in Maize (Zea mays L.) under Greenhouse Conditions Using the YOLOv5 v7.0 Model

Corn (Zea mays L.) is one of the most important cereals worldwide. To maintain crop productivity, it is important to eliminate weeds that compete for nutrients and other resources. The eradication of these causes environmental problems through the use of agrochemicals. The implementation of technology to mitigate this impact is also a challenge. In this work, an artificial vision system was implemented based on the YOLOv5s (You Only Look Once) model, which uses a single convolutional neural network (CNN) that allows differentiating corn from four types of weeds, for which a mobile support structure was built to capture images. The performance of the trained model had a value of mAP@05 (mean Average Precision) at a threshold of 0.5 of 83.6%. A prediction accuracy of 97% and a mAP@05 of 97.5% were obtained for the maize class. For the weed classes, Lolium perenne, Sonchus oleraceus, Solanum nigrum, and Poa annua obtained an accuracy of 86%, 90%, 78%, and 74%, and a mAP@05 of 81.5%, 90.2%, 76.6% and 72.0%, respectively. The results are encouraging for the construction of a precision weeding system.

DNA- and Selectable-Marker-Free Genome-Editing System Using Zygotes from Recalcitrant Maize Inbred B73.

Genome-editing tools such as the clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system have become essential tools for increasing the efficiency and accuracy of plant breeding. Using such genome-editing tools on maize, one of the most important cereal crops of the world, will greatly benefit the agriculture and the mankind. Conventional genome-editing methods typically used for maize involve insertion of a Cas9-guide RNA expression cassette and a selectable marker in the genome DNA; however, using such methods, it is essential to eliminate the inserted DNA cassettes to avoid legislative concerns on gene-modified organisms. Another major hurdle for establishing an efficient and broadly applicable DNA-free genome-editing system for maize is presented by recalcitrant genotypes/cultivars, since cell/tissue culture and its subsequent regeneration into plantlets are crucial for producing transgenic and/or genome-edited maize. In this study, to establish a DNA-free genome-editing system for recalcitrant maize genotypes/cultivars, Cas9-gRNA ribonucleoproteins were directly delivered into zygotes isolated from the pollinated flowers of the maize-B73 cultivar. The zygotes successfully developed and were regenerated into genome-edited plantlets by co-culture with phytosulfokine, a peptide phytohormone. The method developed herein made it possible to obtain DNA- and selectable-marker-free genome-edited recalcitrant maize genotypes/cultivars with high efficiency. This method can advance the molecular breeding of maize and other important cereals, regardless of their recalcitrant characteristics.