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Climate change-caused water deficiency is a major threat to crop production. Different strategies such as biochar and mycorrhiza are suggested as a solution to improve water storage in the soil and increase plant tolerance to moisture deficiency. This study tested the hypothesis that under deficit irrigation conditions, the combined application of biochar and mycorrhiza can increase maize photosynthesis activity, growth, and water use efficiency (WUE). A greenhouse experiment was established to understand the effect of biochar and mycorrhizal inoculation with deficit irrigation on maize (Zea mays L.) growth, photosynthesis activity, and WUE. A factorial randomized pot experiment was designed using three biochars (B) doses from three different feedstock (DF) and three mycorrhizae (M) species (without mycorrhizae, Rhizophagus clarus and indigenous mycorrhiza), with three different irrigation (I) levels, namely, I100, I75, and I50 respectively 100%, 75%, and 50% of field capacity. For each biochar application, of 0%, 1%, and 2% rates of soil weight were applied. Maize plant dry matter (DM), photosynthesis activities, and leaf water use efficiency (WUEL) were measured. The results showed that deficit irrigation levels, such as I75 and I50 can be used for maize plant growth. Mycorrhizal inoculation increased maize plant growth between 8.2% and 8.9%, whereas biochar increased growth. In addition, mycorrhizal inoculation increased the photosynthesis activity by 9.3%. All the biochars increased maize growth and photosynthesis activity compared to the control, however, poultry manure biochar had the highest growth, photosynthesis activity, and WUE. In addition, statistically, there were no significant differences between B0*M0*I100 and B*M*I50 applications in terms of photosynthesis activity, WUE, and DM. Combined application of biochar and mycorrhiza statistically reduced irrigation water use by 50% without affecting plant DM production. [ABSTRACT FROM AUTHOR]

Salt stress significantly impairs plant growth, presenting a challenge to agricultural productivity. Exploring the regulatory mechanisms underlying salt stress responses is critically important. Here, we identified a significant role for the maize LESION-SIMULATING DISEASE transcription factor, ZmLSD1, in enhancing salt stress response. Subcellular localization analysis indicated that ZmLSD1-GFP was localized in the nucleus in the maize protoplast. Overexpressing ZmLSD1 in maize obviously enhanced the tolerance of plants to salt stress. Physiological analysis indicated that overexpressed ZmLSD1 in maize could mitigate the accumulation of H2O2 and MDA content exposed to salt stress. RNA-seq and qPCR-PCR analyses showed that ZmLSD1 positively regulated ZmWRKY29 expression. ChIP-qPCR and EMSA experiments demonstrated that ZmLSD1 could directly bind to the promoter of ZmWRKY29 through the GTAC motif both in vitro and in vivo. Overall, our findings suggest that ZmLSD1 plays a positive role in enhancing the tolerance of maize to salt by affecting ZmWRKY29 expression. [ABSTRACT FROM AUTHOR]

Introduction: Melatonin, a tryptophan-derived indoleamine metabolite with important roles in plant growth and defense, has recently been regarded as a new plant hormone. Maize is one of the most important cereal crops in the world. Although the melatonin receptor gene, ZmPMTR1, has already been identified, the genetic basis of melatonin biosynthesis in maize has still not been elucidated. Serotonin N-acetyltransferase (SNAT) is the enzyme that converts serotonin to N-acetylserotonin (NAS) or 5-methoxytryptamine (5MT) to melatonin in Arabidopsis and rice, but no SNAT encoding gene has been identified yet in maize. Methods: The bioinformatics analysis was used to identify maize SNAT genes and the enzyme activity of the recombinant proteins was determined through in vitro assay. The expression levels of ZmSNAT1 and ZmSNAT3 under drought and heat stresses were revealed by public RNA-seq datasets and qRT-PCR analysis. Results: We first identified three maize SNAT genes, ZmSNAT1, ZmSNAT2, and ZmSNAT3, through bioinformatics analysis, and demonstrated that ZmSNAT2 was present in only eight of the 26 cultivars analyzed. We then determined the enzyme activity of ZmSNAT1 and ZmSNAT3 using their recombinant proteins through in vitro assay. The results showed that both ZmSNAT1 and ZmSNAT3 could convert serotonin to NAS and 5-MT to melatonin. Recombinant ZmSNAT1 catalyzed serotonin into NAS with a higher catalytic activity (Km, 8.6 mM; Vmax, 4050 pmol/min/mg protein) than ZmSNAT3 (Km, 11.51 mM; Vmax, 142 pmol/min/mg protein). We further demonstrated that the 228th amino acid Tyr (Y228) was essential for the enzymatic activity of ZmSNAT1. Finally, we revealed that the expression of ZmSNAT1 and ZmSNAT3 varied among different maize cultivars and different tissues of a plant, and was responsive to drought and heat stresses. Discussion: In summary, the present study identified and characterized the first two functional SNAT genes in maize, laying the foundation for further research on melatonin biosynthesis and its regulatory role in plant growth and response to abiotic stresses. [ABSTRACT FROM AUTHOR]

Intercropping can improve light interception and crop yield on limited farmlands. The light interception rate in intercropping is determined by row configuration. Quantifying the spatio-temporal light interception of intercrops is very important for improving crop yields by optimizing the row configuration. A two-year field experiment was conducted at two sites to quantify the responses of the light interception rate of intercrops to five treatments: two rows of maize alternated with three rows of soybean (2M3S), two rows of maize alternated four rows of soybean (2M4S), two rows of maize alternated five rows of soybean (2M5S), sole soybean (SS), and sole maize (SM). We developed a multiple regression model based on the sine of the solar elevation angle (sin(h)) and crop leaf area density (LAD) to quantify the spatio-temporal light interception of intercrops. The predicted light interception rate was positively correlated with the measured values of photosynthetically active radiation (R² > 0.814) and dry matter (R² > 0.830). Increasing soybean rows led to an increase in light interception of both soybean and the lower layer of maize. However, this also resulted in a decrease in light interception in the upper layer of maize. At the two sites, compared to 2M3S, the annual average cumulative light interception of soybean in 2M5S increased by 44.73% and 47.18%, that of the lower layer of maize in 2M5S increased by 9.25% and 8.04%, and that of whole canopy of maize decreased by 13.77% and 17.74% respectively. The changes in dry matter and yield of intercrops were consistent with the change in light interception, which further verified the high accuracy of the light interception model. The annual average maize yield of 2M5S was 6.03% and 6.16% lower but the soybean yield was 23.69% and 28.52% higher than that of 2M3S. On the basis of system yield, the best performance was recorded in 2M4S at the two sites. In summary, the newly created light interception model performs well in the quantification of the temporal and spatial changes in crop light interception in strip intercropping and has potential applications in other configurations. Optimizing row configurations across climatic regions to enhance light interception and yield at the system level will become a future target. [ABSTRACT FROM AUTHOR]

Summary Class 2 Type V‐A CRISPR‐Cas (Cas12a) nucleases are powerful genome editing tools, particularly effective in A/T‐rich genomic regions, complementing the widely used CRISPR‐Cas9 in plants. To enhance the utility of Cas12a, we investigate three Cas12a orthologs—Mb3Cas12a, PrCas12a, and HkCas12a—in plants. Protospacer adjacent motif (PAM) requirements, editing efficiencies, and editing profiles are compared in rice. Among these orthologs, Mb3Cas12a exhibits high editing efficiency at target sites with a simpler, relaxed TTV PAM which is less restrictive than the canonical TTTV PAM of LbCas12a and AsCas12a. To optimize Mb3Cas12a, we develop an efficient single transcription unit (STU) system by refining the linker between Mb3Cas12a and CRISPR RNA (crRNA), nuclear localization signal (NLS), and direct repeat (DR). This optimized system enables precise genome editing in rice, particularly for fine‐tuning target gene expression by editing promoter regions. Further, we introduced Arginine (R) substitutions at Aspartic acid (D) 172, Asparagine (N) 573, and Lysine (K) 579 of Mb3Cas12a, creating two temperature‐tolerant variants: Mb3Cas12a‐R (D172R) and Mb3Cas12a‐RRR (D172R/N573R/K579R). These variants demonstrate significantly improved editing efficiency at lower temperatures (22 °C and 28 °C) in rice cells, with Mb3Cas12a‐RRR showing the best performance. We extend this approach by developing efficient Mb3Cas12a‐RRR STU systems in maize and tomato, achieving biallelic mutants targeting single or multiple genes in T0 lines cultivated at 28 °C and 25 °C, respectively. This study significantly expands Cas12a's targeting capabilities in plant genome editing, providing valuable tools for future research and practical applications. [ABSTRACT FROM AUTHOR]

Maize (Zea mays) is one of the most important crops in the world, but its yield and quality are seriously affected by diverse diseases. Identifying broad-spectrum resistance genes is crucial for developing effective strategies to control the disease in maize. In a genome-wide study in maize, we identified a G-type lectin receptor kinase ZmLecRK1, as a new resistance protein against Pythium aphanidermatum , one of the causal pathogens of stalk rot in maize. Genetic analysis showed that the specific ZmLecRK1 allele can confer resistance to multiple pathogens in maize. The cell death and disease resistance phenotype mediated by the resistant variant of ZmLecRK1 requires the co-receptor ZmBAK1. A naturally occurring A404S variant in the extracellular domain of ZmLecRK1 determines the ZmLecRK1-ZmBAK1 interaction and the formation of ZmLecRK1-related protein complexes. Interestingly, the ZmLecRK1 susceptible variant was found to possess the amino acid S404 that is present in the ancestral variants of ZmLecRK1 and conserved among the majority of grass species, while the resistance variant of ZmLecRK1 with A404 is only present in a few maize inbred lines. Substitution of S by A at position 404 in ZmLecRK1-like proteins of sorghum and rice greatly enhances their ability to induce cell death. Further transcriptomic analysis reveals that ZmLecRK1 likely regulates gene expression related to the pathways in cell wall organization or biogenesis in response to pathogen infection. Taken together, these results suggest that the ZmLecRK1 resistance variant enhances its binding affinity to the co-receptor ZmBAK1, thereby enhancing the formation of active complexes for defense in maize. Our work highlights the biotechnological potential for generating disease-resistant crops by precisely modulating the activity of ZmLecRK1 and its homologs through targeted base editing. The G-type lectin receptor kinase ZmLecRK1 confers multiple disease resistance in maize. A naturally occurring A404S variant in ZmLecRK1 determines the ZmLecRK1-ZmBAK1 interaction for defense. The susceptible variant of ZmLecRK1 with S404 that is conserved among the majority of grass species constitutes the ancestral variants of ZmLecRK1, while the resistance variant with A404 is only present in a few maize inbred lines. [ABSTRACT FROM AUTHOR]

Background: Sorghum downy mildew (SDM) of maize caused by the fungus Peronosclerospora sorghi (Weston and Uppal) C.G. Shaw is one of the most important diseases of maize and it remains vital constraint in maize production. Since maize is the highly cross pollinated crop, exploitation of heterosis is one of the breeding methods to increase the production. Negative values in the expression of heterosis indicate a contribution towards resistance which is highly needed in order to have reduced incid ence of sorghum downy mildew in maize hybrids. Methods: The materials selected as parents for the present study consisted of nine maize inbred lines which comprised of three resistant (UMI102, UMI936(w) and UMI285), three moderately resistant (UMI176, UMI13 and UMI57) and three susceptible (UMI79, UMI432 and UMI467) inbreds to SDM incidence. Nine inbred lines were crossed in all possible combinations including reciprocals in diallel fashion and the resultant seventy two hybrids along with their parents and the check (COH(M)5) were raised and evaluated for resistance against SDM under glass house condition. The extent of heterosis was estimated over mid parent, better parent and popular check hybrid. Result: Analysis of variance for sorghum downy mildew incidence revealed highly significant differences among parents and hybrids indicating greater diversity among the genotypes for sorghum downy mildew incidence under study. Out of seventy two hybrids, only three hybrids namely UMI 13 × UMI 936 (W), UMI 467 × UMI 936 (W) and UMI 432 × UMI 936 (W) exhibited three types heterosis significantly in negative direction. [ABSTRACT FROM AUTHOR]

Background: Understanding the complex relationship between soil characteristics and crop production is crucial for sustainable agriculture practices. Soil physicochemical properties such as pH, electrical conductivity (EC), organic matter (OM) and nutrient content (e.g., NPK) significantly influence crop yield. Additionally, the application of straw mulch can impact soil moisture retention, there by affecting crop growth and productivity. Intercropping system offers potential advantages in terms of water use efficiency (WUE) and productivity compared to monoculture system. Methods: The experiment was conducted using a randomised block design (RBD) with three replications. The study included six treatments with different cropping system: T1 = Monoculture soybean(planting size 30×10 cm), T2 = Monoculture maize (planting size 45×15 cm),T3 = Maize + soybean (2:2) line sown,T4 = Maize intercropping with soybean (2:2) + wheat straw (5 tha-1), T5 = Maize intercropping with soybean (2:2) + maize straw (5 tha-1), T6 = Maize intercropping with soybean (2:2) + mustard straw (5 tha-1). Result: Water use efficiency (WUE) varied among treatments, with the highest WUE (9.44) observed in application of maize straw mulch 5t ha-1, indicating 42.57% increases compared to monoculture maize and 42.17% increases compared to monoculture soybean cultivation. Similarly, superior grain yield (19.30 q ha-1), pod yield (16.29 q ha-1), intercrop yield (35.59 q ha-1), maximum maize equivalent yield (54.33 q ha-1) when comparing the results with and without straw mulch applied to maize and soybean crops. Maize and soybean intercropping system demonstrated superior land utilization efficiency (LER:1.04 to 1.24) and productivity metrics. [ABSTRACT FROM AUTHOR]

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is the most important pest on maize (Zea mays L.) crops in Mexico and can cause substantial economic losses if left unmanaged. Commonly, growers carry out some control strategies when observe damage caused by S. frugiperda in their crops without considering whether the level of damage is sufficient to warrant any action. Some authors suggest considering as reference a level damage of 20% or more. Nevertheless, the Sinaloa growers lack of a practical method to estimate such damage. Therefore, the objective of this research was to develop a sequential sampling method that can determine the most appropriate time to initiate a control strategy and that can be applied by the producers of Sinaloa, Mexico. Three trials were established during the 2019–2020 fall-winter planting cycle in the state of Sinaloa, Mexico in regions of the state where maize is commercially grown to evaluate six different sequential sampling methods. The results indicate the best option was a sequential sampling plan based on the Taylor method, performing the regression analysis with Log10, with a maximum of 50 sampling units per plot. [ABSTRACT FROM AUTHOR]

Busseola fusca (Fuller) (Noctuidae), Chilo partellus (Swinhoe) (Crambidae), Eldana saccharina (Walker) (Pyralidae), Helicoverpa armigera (Hübner) (Noctuidae), Sesamia calamistis (Hampson) (Noctuidae) and Spodoptera frugiperda (J.E. Smith) (Noctuidae) are six of the most important insect pests of sugarcane, sorghum and maize in Africa. Suitable artificial diets are needed for the continuous rearing of these species in sufficient numbers to support research on Bt protein-incorporated artificial diet bioassays, screening for host plant resistance, as well as for monitoring of insecticide and Cry-protein resistance evolution in pest populations. This study evaluated diet protocols for rearing of these species. Different noctuid and crambid diets were evaluated and the following life history parameters were recorded: larval survival and mass, larval duration, pupation rate, pupal mass, duration of pupal period and sex ratio. Chilo partellus, E. saccharina and H. armigera excelled on a sugarcane-incorporated diet with high larval survival and mass, pupation and the quickest development to adults. Busseola fusca, S. calamistis and S. frugiperda performed better on a maize leaf-incorporated diet. These two diets are considered optimal for the respective species and are recommended for use in rearing of these species. [ABSTRACT FROM AUTHOR]

The experiment was carried out during rabi (September, 2018-January, 2019) season under water deficit experimental fields at Annamalai University, Tamil Nadu, India to evaluate the performance of maize inbreds under water deficient conditions and to identify potential diverse inbreds for hybridization programme. Ten quantitative characters were studied for variability studies, whereas genetic diversity was observed at both molecular and phenotypic levels. The genotype, G34 showed the highest mean for single plant yield (SPY) (135.6 g), this was followed by G11, G32, G38 and G48. While the genotypes G20 and G50 showed early days to 50% tasseling (DT) and silking (<55 days). High heritability and genetic advance as per cent of mean was observed for the traits leaf area, number of kernels cob-1 and SPY, showing the action of additive gene action. Path analysis showed that SPY had positive direct effects from days to DT, plant height, leaf area, cob length, number of kernels and test weight. Cluster analysis based on Mahalanobis (D2) diversity analysis partitioned the 52 genotypes into 5 clusters, whereas mean Euclidean distance based molecular clustering using the six markers partitioned the selected fourteen genotypes into six clusters. Overall based on both these diversity analyses the genotypes G34, G20, G16, G48, G50, G40 and G34 can be selected and used as parents in future hybridization programme to get superior high yielding hybrids. [ABSTRACT FROM AUTHOR]

Low nutrient use efficiency (NUE) of conventional chemical fertilizers has resulted in the loss of costly nutrients and related environmental implications. Consequently, enhancing crop productivity and nutrient use efficiency are major challenges. In this backdrop, a field experiment was conducted to study the impact of pine oleoresin (POR) and neem oil (NO) coated urea (CU) fertilizers on crop productivity and nutrient recovery efficiency in maize-wheat cropping system grown on Vertisols of central India. The treatment combinations were POR-CU and NO-CU at 100% and 75% of recommended doses of fertilizers (RDF); normal urea (100% RDF); and an unfertilized control. Two years results indicated that the increment in grain yields due to POR-CU and NO-CU applications were 18.8% and 11.7% for maize and 11.6% and 3.49% for wheat, respectively, over normal urea. The apparent recovery efficiency of N (REN) for PORCU, NO-CU, and normal urea at 100% RDF were 65.8%, 64.2%, and 51.4% in maize and 43.2%, 37.0%, and 34.6% in wheat, respectively. There was no significant difference noticed between POR-CU and NO-CU with respect to grain yield and N recovery efficiency. Hence, the study suggested that POR-CU could be a possible alternative option to NO-CU for improving crop yield and NUE. However, further research is needed to determine how effective POR-CU is in diverse agricultural systems and climatic conditions. [ABSTRACT FROM AUTHOR]

Climatic changes pose a continuing danger to food production, impacting people's livelihoods worldwide. Salt and drought stresses have significantly impeded global maize output. RNA editing (RE) is a post-transcriptional process and has a unique function in regulating responses to environmental stimuli. The function of RNA editing sites (RES) in maize plants exposed to salt and water stresses has not been well investigated. In this study, two maize genotypes, sensitive to salt (SS) and resistant to salt (ST) were used. We investigated how salt and water stressors impact RNA editing sites in the whole mRNA derived from the maize nuclear genome. The average alignment rate was 90% for SS and 80% for ST genotypes when compared to the reference genome. Most of the editing events were non-synonymous codon alterations, and the trend in amino acid modifications was mostly hydrophobic. When we compared the root and shoot samples from the treated and control groups, we found that both groups had twelve different types of REs including A/C, A/G (A/I), A/T, C/A, C/G, C/T (C/U), G/A, G/C, G/T, T/A, T/C, and T/G. The treated samples showed an overall improvement in RE efficiency. Gene Ontology analysis showed that the mapped genes participated in several biological processes and molecular activities. The analysis of the whole genome's encoded RNA-edited genes showed that 26 sites were altered from C to T (C to U) in the genes ZemaCp023, ZemaCp001, and Zm00001eb437010. Three A/G (A/I) REs were exclusively linked to ZemaCp001. These results will serve as a foundation for identifying RES in other crops and will also be helpful in the development of salt and water tolerance in maize. [ABSTRACT FROM AUTHOR]

Climate change is projected to decrease maize yields due to warmer temperatures and their consequences. Studies using crop growth models (CGMs), however, have predicted that, through a combination of alterations to planting date, flowering time, and maturity, these yield losses can be mitigated or even reversed. Here, we examine three assumptions of such studies: (1) that climate has driven historical phenological trends, (2) that CGM ensembles provide unbiased estimates of yields under high temperatures, and (3) that the effects of temperature on yields are an emergent property of interactions between phenology and environment. We used data on maize phenology from the United States Department of Agriculture, a statistical model of maize hybrid heat tolerance derived from 80 years of public yield trial records across four US states, and outputs of an ensemble of CMIP6 climate models. While planting dates have advanced historically, we found a trend toward later planting dates after 2005 and no trend for silking or maturity, shifting more time into the reproductive period. We then projected maize yields using the historical model and crop calendars devised using three previously proposed adaptation strategies. In contrast to studies using CGMs, our statistical yield model projected severe yield losses under all three strategies. Finally, we projected maize yields accounting for historical genetic variability for heat tolerance, discovering that it was insufficient to overcome the negative effects of projected warming. These projections are driven by greater heat stress exposure under all crop calendars and climate scenarios. Combined with analysis of the internal sensitivities of CGMs to temperature, our results suggest that current projections do not adequately account for the effects of increasing temperatures on maize yields. Climate adaptation in the US Midwest must utilize a richer set of strategies than phenological adaptation, including improvements to heat tolerance and crop diversification. [ABSTRACT FROM AUTHOR]

The article presents an analysis of the gynogenesis (Zm_Pla1, Zm_CenH3, Zm_Dmp7) genes originated from haploid-inducing (ZMS-8, ZMS-P) and control (KM, GPL-1) maize lines of Saratov breeding. By sequencing and subsequent multiple alignment of the target gene transcripts of the studied maize lines and the reference B73 line, the presence of single nucleotide polymorphism (SNP), deletions, and insertions were determined, phylogenetic trees for the studied genes were constructed. The presence of a 4-nucleotide insertion (4NI) in the Zm_Pla1 gene originated from the Stock 6 ancestral line has been established in haploid-inducing (ZMS-8 and ZMS-P) maize lines, as well as 15 identical SNP. But the parthenogenetic AT-1, AT-3 and AT-4 maize lines, which also have Stock 6 as ancestral line, lack of 4NI in the Zm_Pla1 gene. Phylogenetic analysis of the Zm_Pla1 gene confirmed the relationship of the haploid-inducing Stock 6, ZMS-P, and ZMS-8 maize lines. The Zm_Dmp7 gene recorded the presence of 5 SNP in the ZMS-8 line and 3 SNP in the ZMS-P and KM maize lines. One of the SNP (at position 131 from the start codon) in the Zm_Dmp7 gene is the cause of the increased haploid-inducing ability of the CAU5, but not the ZMS-P maize line. In addition, a 3-nucleotide deletion was found in the Zm_Dmp7 gene in the ZMS-P line and a 9-nucleotide deletion in the KM maize line. [ABSTRACT FROM AUTHOR]

Phosphorus (P) application can enhance soil P availability and alter P fractions. However, the P accumulation and transformation of different P sources in low-phosphorus red soil remain unclear. Two-year (2018–2019) field experiments were conducted to investigate the effects of five P source treatments (CK—no phosphorus; SSP—superphosphate; MAP—calcium–magnesium phosphate; DAP—monoammonium phosphate; and CMP—diammonium phosphate) on the P accumulation of maize and soil P fractions in low-P red soil using the Hedley Sequential Method. The results showed that P application significantly increased P uptake, Olsen-P, total phosphorus, and most of the soil P fractions. Compared to the CMP, MAP, and DAP treatments, SSP had a relatively higher P accumulation and labile P pool, with a slightly lower moderately labile P pool. The SSP treatment mainly increased soil-available P content and crop P uptake by increasing the labile P pool (resin-P and NaHCO3-Pi) and reducing the moderately labile P pool and non-labile P pool. The P activation coefficient (PAC%) and Olsen-P were positively correlated with labile P (resin-P, NaHCO3-Pi, and NaHCO3-Po) and moderately labile P (NaOH-Pi and 1 M HCl-Pi) and negatively correlated with Fe2O3 and Al2O3. The results suggest that SSP has a priority effect on the crop P uptake and soil P availability in low-P red soil. [ABSTRACT FROM AUTHOR]

A substrate-based production system is a simple and low-cost method for arbuscular mycorrhizal (AM) fungal inoculum production. However, it is time-consuming and typically yields low numbers of AM fungal spores due to several factors affecting plant growth efficiency. Our study investigated the use of light-emitting diode (LED) technology to expedite AM fungal spore production in planta. We performed experiments with Rhizophagus irregularis inoculated in maize (Zea mays L.), contrasting LED light with greenhouse (GH) conditions. Our results exhibited a significant improvement in AM fungal colonization and spore production, as well as a reduction in the production period from 120 to 90 days under the LED light condition. This was achieved using a red-and-blue light ratio of 60:40 with a total light intensity of 300 µmol m−2 s−1. The LED light treatments improved maize growth by increasing nitrogen (N) and phosphorus (P) concentrations in shoots and roots, respectively. Our gene expression analyses revealed that in AMF-inoculated plants, genes related to photosynthesis were significantly upregulated under LED light compared to the GH condition. Moreover, LED increased the expression of marker genes linked to the AM fungi-related cell cycle, indicating enhanced AM fungal growth during symbiosis. These findings advance our comprehension of LED applications in agriculture, offering promising prospects for acceleration of AM fungal spore production. [ABSTRACT FROM AUTHOR]

In order to reduce the actual impact of a saline–alkali environment on maize production in semi-arid areas, it is particularly important to use the combined fertilization strategy of Trichoderma microbial fertilizer and nitrogen fertilizer. The purpose of this study was to investigate the effects of different concentrations of nitrogen fertilizer combined with Trichoderma on improving the structural characteristics and ecological functions of maize rhizosphere microbial community in semi-arid saline–alkali soil. Through the microbiome analysis of maize rhizosphere soil samples with 60 kg N·ha−1 (N1) and 300 kg N·ha−1 (N2) nitrogen fertilizer combined with Trichoderma (T1) and without Trichoderma (T0), we found that the combination of Trichoderma and different concentrations of nitrogen fertilizer significantly affected the structure of bacterial and fungal communities. The results of this study showed that the combination of Trichoderma and low-concentration nitrogen fertilizer (N1T1) could improve soil nutritional status and enhance its productivity potential, revealing the relationship between beneficial and harmful fungal genera, microbial diversity and abundance, and crop biomass, which is of great significance for improving agricultural production efficiency and sustainable development. [ABSTRACT FROM AUTHOR]

Sulfur (S) is an essential nutrient for plant growth, influencing not only crop yields but also the composition and function of soil microbial communities. However, the differential effects of S fertilization on abundant and rare taxa in agricultural soils remain poorly understood. This study investigates the impact of different S fertilizer types on maize yield and the structure and stability of soil microbial communities, with a particular focus on abundant and rare taxa. S fertilization led to significant increases maize yield on two typical soils (black soil and sandy soil) (5.3–24.3%) and altered soil properties, including reducing pH (0.04–0.20) and increasing the available sulfur (AS) content (3.8–8.0 mg kg−1), with ammonium sulfate having a more pronounced effect than elemental sulfur. Microbial analysis revealed distinct impacts on the diversity and community structure of both abundant and rare taxa. Elemental sulfur reduced the alpha diversity of abundant taxa more than ammonium sulfate, while NMDS indicated significant shifts in community structures, particularly among abundant taxa. Network analysis showed that S fertilization decreased the complexity of microbial interactions among rare taxa, with ammonium sulfate leading to simpler networks and elemental sulfur resulting in higher modularity. SEM highlighted that the diversity of rare taxa played a crucial role in influencing maize yield, alongside direct effects from soil properties such as AS and SAR (aryl sulfatase). Functional predictions demonstrated that amino acid metabolism and xenobiotic biodegradation and metabolism pathways were enriched in rare taxa, suggesting significant implications for soil health and crop productivity. This study provides new insights into the roles of abundant and rare bacterial taxa under S fertilization, emphasizing their importance in optimizing fertilization strategies for enhanced crop yield in specific soil types. [ABSTRACT FROM AUTHOR]

Blended refuges for corn-expressing toxins from Bacillus thuringiensis (Bt) Berliner controls have been approved in the United States as an alternative resistance management approach to structured refuge. This study examined the impact of blended refuges up to 30% non-Bt seed on the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), larval numbers, and kernel injury, and its effect on corn grain yield and test weights. The percentage of infested ears, larval numbers, and kernel injury of the 20% blend were not significantly different from the non-Bt and nonblended Bt for the Cry1A.105 + Cry2Ab + Cry1Fa2 treatment, but infested ears, larval numbers, and kernel injury of the nonblended Cry1A.105 + Cry2Ab treatment was lower than the comparable non-Bt hybrids, with the 20% blend being intermediate. The nonblended Cry1A.105 + Cry2Ab + Vip3Aa20 had virtually no larvae in ears and no kernel injury. Ear infestation, larval numbers, and kernel injury of the non-Bt blends with Vip3Aa20 were proportional to the percentage of non-Bt seed in the blend, and all infested ears were from the non-Bt refuge plants. Grain yield and test weight were not significantly different among nonblended or blended treatments of any Bt product tested. Results indicate losses of grain yield and test weight by corn earworm in seed blends up to 30% non-Bt seed are unlikely with infestation levels observed in this study. [ABSTRACT FROM AUTHOR]

Simple Summary: The corn leafhopper, an invasive insect and vector of corn stunt spiroplasma, has been reported in multiple counties in Oklahoma. Corn stunt spiroplasma-infected corn leafhoppers were also confirmed in the state. The corn leafhopper, Dalbulus maidis (DeLong and Wolcott) (Hemiptera: Cicadellidae), is an invasive insect that can cause damage to maize (Zea mays L.) in two ways: by direct feeding and the transmission of several plant pathogens. Dalbulus maidis is an invasive and serious economic pest of maize that has spread from its center of origin in Mexico to the southernmost parts of the United States. Prior to 2024, corn leafhoppers had not been documented in Oklahoma, and their spread northward toward the United States corn belt is of significant concern. Here, we provide the first reports of the insect in maize in several Oklahoma counties. Insect specimens were collected at various commercial and experimental field sites by Oklahoma State University research and extension personnel. The identity of the insect species was validated through morphological and molecular taxonomy. The presence records for the corn leafhopper presented here provide valuable information for future monitoring and management efforts of this economically important pest and disease. [ABSTRACT FROM AUTHOR]

The recessive opaque2 (o2) gene enhances lysine and tryptophan by ~ twofold in maize kernels. Despite > 6 decades of research, no functional marker for o2 has been reported yet. Here, we sequenced 2848 bp of entire o2 gene in 10 diverse inbreds, and identified 7 exonic SNPs and 3 exonic InDels that distinguished the normal and quality protein maize (QPM) inbreds. Of these, three potential SNPs (SNP601_T/C, SNP2359_C/T and SNP2360_G/T) and three InDels (InDel_1, InDel_8 and InDel_9) were responsible for modification of amino acids. Clustering analysis grouped 24 QPM and 24 normal inbreds into two clusters, and led to the identification of 24 haplotypes of o2. Insertion of alanine was found to regulate the binding of o2 protein with promoter of zein genes. QPM inbreds possessed significantly higher lysine (0.271–0.406%) and tryptophan (0.069–0.101%) compared to normal (lysine: 0.124–0.213%; tryptophan: 0.029–0.047%). A functional marker (MGU-InDel10-o2) was developed, and it clearly differentiated the QPM and normal inbreds. MGU-InDel10-o2 successfully identified desirable plants in BC1F1, BC2F1 and BC2F2 populations. BC2F3 progenies possessed higher lysine (0.379%) and tryptophan (0.084%) over original inbreds (lysine: 0.189% and tryptophan: 0.039%). Among haplotypes, Hap-3 showed the highest average lysine (0.380%) and tryptophan (0.094%), while Hap-14 and Hap-16 had the lowest lysine (0.124%) and tryptophan (0.029%), respectively. This is the first report on understanding allelic variation, haplotypes and functional marker development for o2 gene in maize. [ABSTRACT FROM AUTHOR]

The oil content of maize kernels is essential to determine its nutritional and economic value. A multiparent population (MPP) consisting of five recombinant inbred line (RIL) subpopulations was developed to elucidate the genetic basis of the total oil content (TOC) in maize. The MPP used the subtropical maize inbred lines CML312 and CML384, along with the tropical maize inbred lines CML395, YML46, and YML32 as the female parents, and Ye107 as the male parent. A genome-wide association study (GWAS) was performed using 429 RILs of the multiparent population across three environments, employing 584,847 high-quality single nucleotide polymorphisms (SNPs). Furthermore, linkage analysis was performed in the five subpopulations to identify quantitative trait loci (QTL) linked to TOC in maize. Through QTL mapping and GWAS, 18 QTLs and 60 SNPs that were significantly associated with TOC were identified. Two novel candidate genes, Zm00001d029550 and Zm00001d029551, related to TOC in maize and located on chromosome 1 were reported, which have not been previously reported. These genes are involved in biosynthesis, lipid signal transduction, plant development and metabolism, and stress responses, potentially influencing maize TOC. Haplotype analysis of Zm00001d029550 and Zm00001d029551 revealed that Hap3 could be considered a superior haplotype for increasing TOC in maize. A co-located SNP (SNP-75791466) on chromosome 1, located 5648 bp and 11,951 bp downstream of the candidate genes Zm00001d029550 and Zm00001d029551, respectively, was found to be expressed in various maize tissues. The highest expression was observed in embryos after pollination, indicating that embryos are the main tissue for oil accumulation in maize. This study provides a theoretical basis for understanding the genetic mechanisms underlying maize TOC and developing high-quality, high-oil maize varieties. [ABSTRACT FROM AUTHOR]

Deep sowing, as a method to mitigate drought and preserve soil moisture and seedlings, can effectively mitigate the adverse effects of drought stress on seedling growth. The elongation of the hypocotyl plays an important role in the emergence of maize seeds from deep-sowing stress. This study was designed to explore the function of exogenous methyl jasmonate (MeJA) in the growth of the maize mesocotyl and to examine its regulatory network. The results showed that the addition of a 1.5 μ mol L−1 MeJA treatment significantly increased the mesocotyl length (MES), mesocotyl and coleoptile length (MESCOL), and seedling length (SDL) of maize seedlings. Transcriptome analysis showed that exogenous MeJA can alleviate maize deep-sowing stress, and the differentially expressed genes (DEGs) mainly include ornithine decarboxylase, terpene synthase 7, ethylene responsive transcription factor 11, and so on. In addition, candidate genes that may regulate the length of maize hypocotyls were screened by Weighted Gene Co-expression Network Analysis (WGCNA). These genes may be involved in the growth of maize hypocotyls through transcriptional regulation, histones, ubiquitin protease, protein binding, and chlorophyll biosynthesis and play an important role in maize deep-sowing tolerance. Our research findings may provide a theoretical basis for determining the tolerance of maize to deep-sowing stress and the mechanism of exogenous hormone regulation of deep-sowing stress. [ABSTRACT FROM AUTHOR]

Maize originated in southern Mexico and various hybrid varieties have been bred during domestication. All maize tissues are rich in specialized plant metabolites (SPMs), which allow the plants to resist the stresses of herbivores and pathogens or environmental factors. To date, a total of 95 terpenoids, 91 phenolics, 31 alkaloids, and 6 other types of compounds have been identified from maize. Certain volatile sesquiterpenes released by maize plants attract the natural enemies of maize herbivores and provide an indirect defensive function. Kauralexins and dolabralexins are the most abundant diterpenoids in maize and are known to regulate and stabilize the maize rhizosphere microbial community. Benzoxazinoids and benzoxazolinones are the main alkaloids in maize and are found in maize plants at the highest concentrations at the seedling stage. These two kinds of alkaloids directly resist herbivory and pathogenic infection. Phenolics enhance the cross‐links between maize cell walls. Meanwhile, SPMs also regulate plant–plant relationships. In conclusion, SPMs in maize show a large diversity of chemical structures and broad‐spectrum biological activities. We use these to provide ideas and information to enable the improvement of maize resistances through breeding and to promote the rapid development of the maize industry. [ABSTRACT FROM AUTHOR]

Maize production and quality are affected by infection with plant pathogens. One of the maize's essential and main diseases is downy mildew caused by Peronosclerospora spp. Downy mildew is a limiting factor in increasing production and can reduce production by 80-100%. It is because the affected plant cannot produce cobs. Pathogens obtain nutrients from the host cell, which can kill the cell and damage the surrounding tissues, resulting in visible downy mildew symptoms. Boron (B) plays a role in forming phloem, increasing the fruit's number, weight, bunch weight, and diameter. The primary function of B at the molecular level is the cross-linking of pectin in the plant cell wall. Ramnogalacturonan II (RG II) is a pectic polysaccharide that contributes to the mechanical strength and properties of the primary wall cross-linked by borate diesters. Phosphorus (P) controls the downsides in the greenhouse and field conditions. This study aims to measure changes in chlorophyll index, P and B uptakes in downy mildew affected plants. The field experiment used a group randomized design with six natural phosphate (FA) application treatments and four groups of borax doses as replicates. The results showed that the downy mildew decreased the chlorophyll index of the leaves at different levels of attack. The results of P concentration according to the position of healthy plant leaves were significantly different due to P treatment. In contrast to concentration B, there is no real difference. P and B uptake results in downy mildew-infested plants showed a significant difference only in P uptake in leaves with 1 FA treatment. [ABSTRACT FROM AUTHOR]

Maize is widely growth in arid and semi-arid region where, drought is common and a limiting factor for crop production. Potassium plays a key role in enhancing plant growth under drought condition. The objective of this study is to determine the effect of K fertilization with and without NP on maize growth grown in sandy loam soil under adequate and deficit irrigation conditions. The following treatments were investigated in pot experiment: (1) control with no fertilizer application (C); (2) 128 kg N + 328 kg P2O5 ha-1 (NPK0); (3) 128 kg N + 328 kg P2O5 ha-1 + 152.5 kg K2O ha1 (NPK1); (4) 128 kg N + 328 kg P2O5 ha-1 + 305 kg K2O ha-1 (NPK2); and 128 kg N + 328 kg P2O5 ha-1 + 457.5 kg K2O ha-1 (NPK3). Treatments were investigated under adequate and deficit soil moisture content. Each pot filled with 3.5 kg air-dry soil and seeded with maize and pots were watered according to the treatments. The results indicated that plant growth and nutrient uptake were significantly reduced under water stress condition. The application of NP increased plant growth and nutrient uptake and further were increased with K application. K application also enhanced plant tolerance to deficit soil moisture condition. In addition, K enhanced nutrient uptake and leaf chlorophyll content. Based on the results, it can be concluded that application of NP for maize was not adequate to achieve the highest plant growth, unless it is combined with K application. In addition, K application enhances plant tolerance to water stress. [ABSTRACT FROM AUTHOR]

Key message: Overexpression of ZmNAC19, a NAC transcription factor gene from maize, improves embryo development in transgenic Arabidopsis. NAC proteins are plant-specific transcription factors that are involved in multiple aspects of plant growth, development and stress response. Although functions of many NAC transcription factors have been elucidated, little is known about their roles in seed development. In this study, we report the function of a maize NAC transcription factor ZmNAC19 in seed development. ZmNAC19 is highly expressed in embryos of developing maize seeds. ZmNAC19 localizes to nucleus and exhibits transactivation activity in yeast cells. Overexpression of ZmNAC19 in Arabidopsis significantly increases seed size and seed yield. During 3 to 7 days after flowering, embryos of ZmNAC19-overexpression Arabidopsis lines developed faster compared to Col-0, while no visible differences were detected for their endosperms. Furthermore, overexpression of ZmNAC19 in Arabidopsis leads to increased transcription levels of two embryo development-related genes YUC1 and RGE1, and several elements proven to be binding sites of NAC transcription factors were observed in promoters of these two genes. Taken together, these results suggest that ZmNAC19 acts as a positive regulator in plant embryo development. [ABSTRACT FROM AUTHOR]

The detection of crop rows is crucial for achieving visual navigation and is one of the key technologies for enabling autonomous management of maize fields. However, the current mainstream approach to maize crop row detection often involves two steps - feature extraction followed by post-processing. While useful, this method is inefficient, and the heuristic rules designed by humans limit the scalability of these methods. To simplify the solution and enhance its generality, crop row detection is defined as a process of approximating curves. Polynomial parameter learning is adopted to constrain the parameters of crop row shapes, and utilise a model built on the Transformer architecture to learn the elongated structures and global context of crop rows, achieving end-to-end output of crop row shape parameters. The proposed approach has achieved rapid and excellent detection results in complex field environments, even in the presence of curved crop rows. • Transforming the extraction of crop rows into a parameter curve regression method. • Utilising a transformer-based model to capture the elongated structure of crop rows. • Effectively addressing curved crop rows. • Achieving high-precision detection along with outstanding detection speed. [ABSTRACT FROM AUTHOR]

Herbivory by insects leads to changes in both primary and secondary plant metabolism, ultimately impacting subsequent interactions. Some phloem‐feeding insects have developed mechanisms to suppress herbivore‐induced plant defences and manipulate the quality of host phloem sap, thereby facilitating their establishment on the host plant. Based on evidence that the specialized phloem‐feeding insects, Dalbulus maidis and Rhopalosiphum maidis, can suppress herbivore‐induced defences in maize, we hypothesized that infestation by either of these pests in maize would facilitate the colonization and establishment of subsequent conspecific and heterospecific individuals. We conducted a series of behavioural assays with these insects in both laboratory and greenhouse settings.The corn leafhopper D. maidis preferred previously infested plants as hosts, but it did not discriminate between conspecific‐ or heterospecific‐infested plants for colonization. However, when selecting a host for oviposition, it preferred depositing eggs on conspecific‐infested plants, which were the hosts that the offspring performed better compared to both non‐infested and heterospecific‐infested plants.The corn aphid R. maidis also preferred previously infested plants over non‐infested plants as hosts. However, the aphid preferred heterospecific‐infested over conspecific‐infested plants, even though heterospecific‐infested plants were hosts of lower quality to aphids. Aphids performed better on conspecific‐infested plants, followed by heterospecific‐infested plants, when compared to non‐infested plants.Our results confirm that previous colonization by the specialized phloem‐feeding insects facilitates subsequent infestations by conspecifics and heterospecifics. However, the facilitation for heterospecifics was asymmetric, as colonization by D. maidis facilitated infestations by R. maidis more than the reverse sequence of infestation. [ABSTRACT FROM AUTHOR]

Sustainable irrigation water management is achievable only when irrigation scheduling is optimized to conserve water and soil resources in an agricultural setting. This study evaluated the use of remote sensing–based algorithms for determining actual crop evapotranspiration (ETa) mapping to update crop coefficients (kc) of an irrigation scheduler software (WISE). The scheduler's kc values are based on the FAO-56 approach for crop evapotranspiration (ETc) determination. A surface-irrigated (furrow) maize (Zea mays L.) field in Fort Collins, Colorado, was used from July to September 2020 and 2021. An eddy covariance energy balance system (ECSEBS) installed on a tower at 3.5 m above the ground surface was used to determine hourly and daily maize ETa data. These EC-based ETa data were used to evaluate the performance of three approaches for maize ETa estimation and the FAO-56–based ETc predictions from WISE. Microsatellite PlanetScope multispectral imagery, at a 3-m-pixel spatial resolution, provided surface reflectance in the red and near-infrared bands for input in the remote sensing of ETa algorithms. On-site micrometeorological data were measured at the exact location of the ECSEBS tower. Optimization of kc values was done using an ordinary least-squares regression approach. The optimized kc values were calculated for the maize midseason growth stage. Results indicated that using remote sensing of ETa algorithms has excellent potential to improve irrigation scheduling by integrating optimized crop coefficients. WISE overestimated daily maize ETc predictions by as much as 26%. When remote sensing-based optimized kc values were introduced, the overestimation of daily maize ETc was reduced significantly, by 18% to 75%, depending on the remote sensing of the ETa algorithm used. The research findings support the combined use of remote sensing data and the FAO-56 approach for irrigation scheduling to improve agricultural water management at the farm level. [ABSTRACT FROM AUTHOR]

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The chlorophyll content (CC) directly affects photosynthesis, growth, and yield. However, the genetic basis of CC is still unclear in maize (Zea mays L.). Here, we conducted a genome-wide association study using mixed linear model for CC of the fifth leaves at seedling stage (CCFSS) and the ear leaves at filling stage (CCEFS) for 334 maize inbred lines. The heritability estimates for CCFSS and CCEFS, obtained via variance components analysis using the lme4 package in R, were 70.84% and 78.99%, respectively, indicating that the CC of leaves is primarily controlled by genetic factors. A total of 15 CC-related SNPs and 177 candidate genes were identified with a p-value < 4.49 × 10−5, which explained 4.98–7.59% of the phenotypic variation. Lines with more favorable gene variants showed higher CC. Meanwhile, Gene Ontology (GO) analysis implied that these candidate genes were probably related to chlorophyll biosynthesis. In addition, gene-based association analyses revealed that six variants in GRMZM2G037152, GRMZM5G816561, GRMZM2G324462, and GRMZM2G064657 genes were significantly (p-value < 0.01) correlated with CC, of which GRMZM2G064657 (encodes a phosphate transporter protein) and GRMZM5G816561 (encodes a cytochrome P450 protein) were specifically highly expressed in leaves tissues. Interestingly, these candidate genes were previously reported to involve in the regulation of the contents of chlorophyll in plants or Chlamydomonas. These results may contribute to the understanding of genetic basis and molecular mechanisms of maize CC and the selection of maize varieties with improved CC. [ABSTRACT FROM AUTHOR]

Fifteen maize cultivars comprising of 14 local cultivars and 1 hybrid were selected for studying the seasonal incidence of maize stem borer, Chilo partellus (Swinhoe). The maximum leaf injury damage was observed in cultivar Medziphema Local-1 with 8.67% and 8.00% infestation and the least incidence of leaf injury damage was observed in cultivar Zarsi Socunoma Local with 3.00% and 2.67% infestation during 2020 and 2021, respectively. The maximum dead hearts damage was observed in the cultivars Khuzama Local and Medziphema Local-1 with 12.23% infestation each and the least dead hearts damage was observed in cultivar Zarsi Socunoma Local with 5.84% infestation during 2020. While during the year 2021, the overall maximum dead hearts damage was observed in cultivar Khuzama Local with 11.69% infestation and the minimum dead hearts damage was observed in cultivar Zarsi Socunoma Local with 5.27% infestation. [ABSTRACT FROM AUTHOR]

The study was carried out to evaluate the radioactivity concentrations of 40K, 232Th and 238U in five maize samples collected from maize farms within Ekiti State, Nigeria. The activity concentration measurements were determined using n -- type co-axial HPGe detectors for the state. The activity concentrations were found to vary from 994.67 - 2457.01 Bq Kg-1 for 40K, 32.84 - 91.88 Bq kg-1 for 232Th and 43.21 - 97.77 Bq kg-1 for 238U respectively. The annual effective dose to individuals from the consumption of the Maize was estimated on the basis of the measured radionuclides content in the food crop which ranged between 0.41 and 1.51 m Svy-1 respectively. The value 1.04 m Svy-1 were obtained for the state as the mean total annual effective dose. The mean excess life time cancer risk was also calculated to be 2.06x10-9. The value was compared with the internationally acceptable limits and found to be far less to the maximum permissible dose of 1.0 x10-3 recommended for the public by the United Nations Scientific Committee on the Effects of Atomic Radiation. Hence, the maize was found to be safe for human consumption. [ABSTRACT FROM AUTHOR]

This study was conducted to predict the grain yield of a maize crop from easy-to-measure growth parameters and select the best treatment combinations of biochar, inorganic fertilizer, and irrigation for the maize grain yield and water use efficiency (WUE) using the Principal Component Analysis (PCA) technique. Two rates of biochar (0 and 20 t ha−1) and fertilizer (0 and 300 kg ha−1) were applied to the soil, with maize crop planted, and subjected to deficit irrigation at 60, 80, and 100% of full irrigation amounts (FIA). Maize growth parameters (number of leaves—NL, leaf area—LA, leaf area index—LAI, and plant height—PH) were measured weekly. The results showed that the developed principal component regression (PCR) from the easy-to-measure growth parameters were strong and moderate in predicting the maize yield and WUE, with coefficient of determination; r2 values of 0.92 and 0.56, respectively. Using the PCA technique, the integration of irrigation with the least amount of water (60% FAI) with biochar (20 t ha−1) and fertilizer (300 kg ha−1) produced the highest ranking on grain yield and water use efficiency. This optimization technique showed that with the adoption of the integrative approach, 40% of irrigation water could be saved for other agricultural purposes [ABSTRACT FROM AUTHOR]

The optimization of artificial pollination is crucial in breeding programs for allogamous plants. In maize, achieving a balance between the labor-intensive nature of controlled pollinations and the need for large-scale production of hybrid seeds, along with considerations of germinability and pollen production, determines the success of genetic improvement programs. Breeding programs in maize have resulted in a reduction in the number of tassel branches to increase light interception and plant density in production fields. However, despite this genetic improvement, the decreased pollen production per plant has raised critical concerns regarding pollination and subsequent ear filling, especially under adverse environmental conditions. The aim of this work was the analysis of factors that can contribute to increasing the efficiency of controlled pollination in maize. The data obtained showed that pollen diameter, flavonoid, and phenolic acid content do not influence the percentage of germination and therefore the efficiency of pollination. The quantity of pollen is a central factor in ensuring the efficiency of controlled pollinations, and the data obtained by comparing traditional varieties with modern hybrids of maize showed that an increase in pollen production is determined by the increase in branching of the male inflorescence. Furthermore, we propose the use of a "smart" pollination method to make this step in maize breeding programs easier and faster. [ABSTRACT FROM AUTHOR]

To improve the expandability, seeding accuracy, and operating speed range of the electric drive system (EDS) of precision seeders, this study constructed an EDS based on a controller area network (CAN) bus and designed a motor controller based on a field-orientated control (FOC) algorithm. Full-factorial bench and field tests based on seed spacing (0.1, 0.2, and 0.3 m) and operating speed (3, 6, 9, 12, and 15 km/h) were carried out to evaluate the performance of the EDS. The results of bench tests showed that seeding quality varied inversely with operating speed and positively with seed spacing. The average quality of feed index (QFI) at 0.1, 0.2, and 0.3 m seed spacing in bench tests was 88.38%, 96.67%, and 97.36%, with the average coefficient of variation (CV) being 20.13%, 16.27%, and 13.20%. Analysis of variance confirmed that both operating speed and seed spacing had a significant effect on QFI and CV (p < 0.001). The analysis of motor rotational speed accuracy showed that the relative error of motor rotational speed above 410 rpm did not exceed 2.24%, and the relative error had less influence on the seeding quality. The average QFI was 85.93%, 95.91%, and 96.24%, with the average CV being 21.12%, 15.50%, and 16.49% at 0.1, 0.2, and 0.3 m seed spacing in field tests. The methods and results of this study can provide a reference for the design and optimization of the EDS in a maize precision seeder and provide an effective solution for the improvement of maize yields. [ABSTRACT FROM AUTHOR]

Inconsistent reports exist on the relationships between key agronomic traits and maize yield. We performed a multivariate analysis of yield and 10 agronomic traits in 59 hybrids to explore maize yields in mountainous areas. The yield per plant (YP) was significantly and positively correlated with kernel weight (KW), growth period (GP), and kernel row number (KRN). KW and KRN had positive effects on YP, whereas kernel rows per ear (KRE) had a negative effect. GP indirectly affected YP. GP, KW, KRN, and ear length (EL) showed the highest grey relational degree with YP. The first four principal components cumulatively accounted for 73.36% of variation. EL, KW, plant height (PH), ear height (EH), GP, KRN, and YP contributed positively to the variation, whereas KRE, shelling percentage (SP), bald-tip length (BTL), and ear girth (EG) contributed negatively. Based on trait similarity, the 59 maize hybrids were classified into two clusters, Clusters I and II. A total of 11 traits were grouped into four clusters, Clusters A–D. Cluster D included KW, GP, KRN, EL, EH, PH, and YP, and the 22 maize hybrids in Cluster I performed better in these traits. These results provide a theoretical basis for the breeding of high-yield maize varieties in mountainous areas. [ABSTRACT FROM AUTHOR]

Climate change has significantly altered crop phenology, which has further impacted crop growth and yield. Accurate monitoring of crop phenology is essential for managing agricultural production in response. However, regional monitoring requires high spatial resolution distribution data, as medium resolution data suffers from mixed pixel issues. This study based on a long‐term high spatiotemporal resolution fusion data set of Normalized Difference Vegetation Index and an annually updated maize distribution data set, used the relative threshold method to identify the maize phenology in 22 provinces of China from 2001 to 2020. We further analyzed the trend of maize phenology and assessed its responses to climate change. The results reveal large inter‐annual fluctuations and spatial variability in maize phenology from 2001 to 2020. The length of the growth season (LOS) of spring maize has prolonged by 4.28 days in the northern maize zone and has shortened by 4.90 days in the southern maize zone. Additionally, the LOS of summer maize in the Huang‐Huai‐Hai region has shortened by 2.24 days. We also found a positive correlation between the length of the vegetative growth stage and the mean temperature and a negative correlation between the length of the reproductive growth stage and accumulated precipitation. This study utilized large‐scale, high‐resolution maize phenology data to analyze the trend of maize phenology and its response to climate change. These findings are expected to provide valuable support for assessing maize growth status and developing agricultural adaptive practices. Plain Language Summary: In recent years, climate change has had a notable impact on the crop phenology, influencing both crop growth and yield. It is crucial to accurately monitor when they grow and harvest to manage agricultural production in response to climate variations. This study used a comprehensive data set combining high spatial and temporal resolution imagery to retrieve the growth stage of maize in 22 provinces of China from 2001 to 2020. We found that maize grew differently across China during this period. The length of the growth season for maize got longer in the northern China and got shorter in the central and southern China. We also found that temperature mainly affected the length of the vegetative growth stage, while rainfall mainly affected the length of the reproductive growth stage. Understanding these changes can help farmers understand how maize is growing and adapt their farming practices to climate change. Key Points: We identified the length of growing season (LOS), vegetative growth stage (VGS) and reproductive growth stage (RGS) of maize in ChinaThe LOS of maize prolonged in northern China and shortened in southern China and the Huang‐Huai‐Hai regionPositive correlation between the length of VGS and temperature, while negative correlation between the length of RGS and precipitation [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) has evolved resistance to insecticidal toxins from Bacillus thuringiensis (Bt) Berliner (Bacillales: Bacillaceae) expressed in genetically engineered corn, Zea mays L. This study provides an overview of field trials from Georgia, North Carolina, and South Carolina evaluating Bt and non-Bt corn hybrids from 2009 to 2022 to show changes in susceptibility in H. zea to Bt corn. The reduction in kernel injury relative to a non-Bt hybrid averaged across planting dates generally declined over time for Cry1A.105 + Cry2Ab2 corn. In addition, there was a significant interaction with planting date used as a covariate. The reduction in kernel injury remained above 80% and did not vary with planting date from 2009 to 2014, whereas a significant decline with planting date was found in this reduction from 2015 to 2022. For Cry1Ab + Cry1F corn, the reduction in kernel injury relative to a non-Bt hybrid averaged across planting dates did not vary among years. The reduction in kernel injury significantly declined with planting date from 2012 to 2022. Kernel injury as a proxy for H. zea pressure was greater in late-planted trials in non-Bt corn hybrids. Our study showed that Bt hybrids expressing Cry1A.105 + Cry2Ab2 are now less effective in later planted trials in reducing H. zea injury; however, this was not the case during the earlier years of adoption of corn expressing these 2 toxins when resistance alleles were likely less frequent in H. zea populations. The implications for management of H. zea and for insect resistance management are discussed. [ABSTRACT FROM AUTHOR]

The quality of corn kernels is crucial for their nutritional value, making the enhancement of kernel quality a primary objective of contemporary corn breeding efforts. This study utilized 260 corn inbred lines as research materials and assessed three traits associated with grain quality. A genome-wide association study (GWAS) was conducted using the best linear unbiased estimator (BLUE) for quality traits, resulting in the identification of 23 significant single nucleotide polymorphisms (SNPs). Additionally, nine genes associated with grain quality traits were identified through gene function annotation and prediction. Furthermore, a total of 697 quantitative trait loci (QTL) related to quality traits were compiled from 27 documents, followed by a meta-QTL analysis that revealed 40 meta-QTL associated with these traits. Among these, 19 functional genes and reported candidate genes related to quality traits were detected. Three significant SNPs identified by GWAS were located within the intervals of these QTL, while the remaining eight significant SNPs were situated within 2 Mb of the QTL. In summary, the findings of this study provide a theoretical framework for analyzing the genetic basis of corn grain quality-related traits and for enhancing corn quality. [ABSTRACT FROM AUTHOR]

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BACKGROUND AND OBJECTIVES: To meet the needs of the global population (9.7 billion people) until 2050, a 45 percent increase in corn production is required. Efforts to enhance corn production may be informed, among others, by precise nitrogen management. The objective of this study is to investigate nitrogen dynamics and accurate nitrogen nutrient management in corn farming through the utilization of a leaf chlorophyll meter and nitrogen response assessments in order to forecast corn yield in tropical upland acid soils. METHODS: The current study was conducted in an Ultisol and verified in an Oxisol. The trial was arranged in a randomized completely block design with eight treatments: 0, 45, 90, 135, 180, 225, 270, and 315 kilograms of nitrogen per hectare, repeated three times. The chlorophyll content of corn leaves was measured at 45 and 60 days after planting, using a chlorophyll meter. An analysis was conducted on the vegetative growth and yield, along with the nitrogen content in the soil, leaf, and grains. FINDINGS: The study found that the application of nitrogen fertilizer at the rate of 180 kilograms per hectare can alter nitrate concentrations in soil and significantly increase nitrogen uptake, growth, and corn yield. The nitrogen fertilizer application reached its peak at 274.5 kilograms per hectare, resulting in chlorophyll meter readings of 52.8 and a corn yield of 8.58 tons per hectare. The corn yield at the rate of maximum nitrogen fertilizer (8.58 tons per hectare) was not significantly different from that at the rate of 180 kilogrammes nitrogen per hectare (8.54 tons per hectare). A robust relationship was observed between corn yields and chlorophyll meter values, exhibiting a correlation coefficient 0.92. CONCLUSION: The study revealed that applying nitrogen fertilizer at the medium rate of 180 kilograms per hectare can increase in nitrogen uptake, growth, and corn yield on tropical upland acid soils. The corn yield did not show a notable variance between the nitrogen fertilization rate of 180 kilograms per hectare and the highest rate of 274.5 kilograms per hectare. In terms of sustainable agriculture management, the medium rate of 180 kilograms of nitrogen is recommended for maximizing crop yield on the upland acid soils and minimizing potential environmental impacts associated with the excessive use of fertilizers. A significant relationship exists between leaf chlorophyll meter measurements and corn yield, indicating that the chlorophyll meter can be utilized as a dependable instrument in the research area for establishing the most effective fertilizer levels. [ABSTRACT FROM AUTHOR]

Leaf rolling is a common adaptive response that plants have evolved to counteract the detrimental effects of various environmental stresses. Gaining insight into the mechanisms underlying leaf rolling alterations presents researchers with a unique opportunity to enhance stress tolerance in crops exhibiting leaf rolling, such as maize. In order to achieve a more profound understanding of leaf rolling, it is imperative to ascertain the occurrence and extent of this phenotype. While traditional manual leaf rolling detection is slow and laborious, research into high-throughput methods for detecting leaf rolling within our investigation scope remains limited. In this study, we present an approach for detecting leaf rolling in maize using the YOLOv8 model. Our method, LRD-YOLO, integrates two significant improvements: a Convolutional Block Attention Module to augment feature extraction capabilities, and a Deformable ConvNets v2 to enhance adaptability to changes in target shape and scale. Through experiments on a dataset encompassing severe occlusion, variations in leaf scale and shape, and complex background scenarios, our approach achieves an impressive mean average precision of 81.6%, surpassing current state-of-the-art methods. Furthermore, the LRD-YOLO model demands only 8.0 G floating point operations and the parameters of 3.48 M. We have proposed an innovative method for leaf rolling detection in maize, and experimental outcomes showcase the efficacy of LRD-YOLO in precisely detecting leaf rolling in complex scenarios while maintaining real-time inference speed.Key message: In this study, we propose an improved object detection algorithm for detecting leaf rolling, a common adaptive response to environmental stresses. It achieves 81.6% mean average precision, surpassing existing methods. [ABSTRACT FROM AUTHOR]

Metal contamination in soil poses a significant environmental concern worldwide, necessitating effective remediation strategies such as phytoremediation. The present study investigated the effects of EDTA dosage (1.5 and 3 mmol kg−1) and two Trichoderma species (T. harzianum and T. aureoviride) on copper (Cu) content and growth of maize plants grown in a Cu-contaminated soil, as well as Cu fractionation in the soil. In the absence of EDTA, only inoculation with T. harzianum led to a significant increase in shoot biomass. Combining fungal inoculum with EDTA only yielded a significant increase in shoot biomass when using T. aureoviride at a low EDTA rate, highlighting the interplay between fungal species and EDTA rates on plant growth. Results also indicated that EDTA application increased Cu bioavailability, enhancing Cu dissolution and root (not shoot) Cu concentrations. Conversely, inoculation with both Trichoderma species reduced Cu mobility and bioavailability in soil, thereby decreasing the shoot Cu concentrations of plants. When combined with EDTA, only application of T. harzianum resulted in an enhanced shoot Cu concentration, whereas combined application of T. aureoviride and EDTA did not make a significant change compared to the corresponding control (no fungal inoculation, no EDTA), possibly due to a lower compatibility of the T. aureoviride isolate with EDTA. Our results demonstrated that EDTA application, in both non-inoculated and inoculated treatments, increased Cu availability by facilitating its redistribution and transformation from less plant-available fractions (residual, Fe/Mn oxide-bound, and carbonate-bound) to the more readily plant-available forms (water-soluble and exchangeable fractions). In conclusion, although individual Trichoderma application proved beneficial for phytostabilization by reducing Cu content and mitigating Cu toxicity in plants, the combined application of EDTA and a compatible Trichoderma isolate (here, the T. harzianum isolate) holds promise for enhancing the phytoextraction capacity of plants. Although using maize has the advantage of being a food crop, to optimize phytoextraction, plant species with superior metal tolerance and phytoextraction capabilities should be selected, exceeding those of maize. [ABSTRACT FROM AUTHOR]

Plant phenotypic plasticity plays an important role in nitrogen (N) acquisition and use under nitrogen-limited conditions. However, this role has never been quantified as a function of N availability, leaving it unclear whether plastic responses should be considered as potential targets for selection. A combined modelling and experimentation approach was adopted to quantify the role of plasticity in N uptake and plant yield. Based on a greenhouse experiment we considered plasticity in two maize (Zea mays) traits: root-to-leaf biomass allocation ratio and emergence rate of axial roots. In a simulation experiment we individually enabled or disabled both plastic responses for maize stands grown across six N levels. Both plastic responses contributed to maintaining a higher N uptake, and plant productivity as N availability declined compared with stands in which plastic responses were disabled. We conclude that plastic responses quantified in this study may be a potential target trait in breeding programs for greater N uptake across N levels while it may only be important for the internal use of N under N-limited conditions in maize. Given the complexity of breeding for plastic responses, an a priori model analysis is useful to identify which plastic traits to target for enhanced plant performance. [ABSTRACT FROM AUTHOR]

A fundamental assumption in plant science posits that leaf air spaces remain vapor saturated, leading to the predominant view that stomata alone control leaf water loss. This concept has been pivotal in photosynthesis and water-use efficiency research. However, recent evidence has refuted this longstanding assumption by providing evidence of unsaturation in the leaf air space of C3 plants under relatively mild vapor pressure deficit (VPD) stress. This phenomenon represents a nonstomatal mechanism restricting water loss from the mesophyll. The potential ubiquity and physiological implications of this phenomenon, its driving mechanisms in different plant species and habitats, and its interaction with other ecological adaptations have. In this context, C4 plants spark particular interest for their importance as crops, bundle sheath cells' unique anatomical characteristics and specialized functions, and notably higher water-use efficiency relative to C3 plants. Here, we confirm reduced relative humidities in the substomatal cavity of the C4 plants maize, sorghum, and proso millet down to 80% under mild VPD stress. We demonstrate the critical role of nonstomatal control in these plants, indicating that the role of the CO2 concentration mechanism in CO2 management at a high VPD may have been overestimated. Our findings offer a mechanistic reconciliation between discrepancies in CO2 and VPD responses reported in C4 species. They also reveal that nonstomatal control is integral to maintaining an advantageous microclimate of relatively higher CO2 concentrations in the mesophyll air space of C4 plants for carbon fixation, proving vital when these plants face VPD stress. [ABSTRACT FROM AUTHOR]