Response Of Maize Research Articles

Responses of maize (Zea mays L.) seedlings growth and physiological traits triggered by polyvinyl chloride microplastics is dominated by soil available nitrogen

As a burgeoning pollutant, microplastics (MPs) has elicited global concern. However, ecological effects and mechanisms of MPs on plant-soil system are still poorly understood. In the present study, the impacts of polyvinyl chloride microplastics (PVC-MPs) on maize (Zea mays L.) seedlings growth and physiological traits and soil properties were discussed through a 30-day pot experiment. Results showed that PVC-MPs had greater toxicity effect on seedlings shoot biomass than root biomass. To defense the impact of PVC-MPs, the superoxide dismutase and catalase activities in seedlings leaf were stimulated. Moreover, the adhesion of MPs on soil particles increased, and soil microorganism, enzymes, and nutrients were altered significantly with increasing content of PVC-MPs. Notably, soil nitrate nitrogen decreased significantly with increasing content of PVC-MPs, whereas soil ammonium nitrogen was promoted under lower contents (0.1% and 1%) of PVC-MPs. Redundancy analysis indicated that soil nitrate nitrogen and ammonium nitrogen can explain 87.4% and 7.7% of variation in maize seedlings growth and physiological traits, respectively. These results display that maize seedlings shoot is more susceptible to the impact of PVC-MPs and soil available nitrogen is the primary limiting factor on maize seedlings growth and physiological traits triggered by PVC-MPs. Impacts of PVC-MPs on maize seedlings growth and physiological traits by nitrogen depletion lead to the possible yield and economic loess and potential risks due to the over use of nitrogen fertilizers.

Investigation of the agroecological applications of olive mill wastewater fractions from the ultrafiltration-nanofiltration process

Agricultural applications of olive mill wastewater (OMW) represent a critical challenge, consistent with waste recycling and the trend towards a more sustainable pattern of agriculture. In this context, an integrated study on the agroecological applications of OMW from the ultrafiltration (UF) - nanofiltration (NF) process was carried out. This process generated three fractions: UF retentate and NF permeate, depleted in salts and phenolic compounds, were studied for their fertilization and irrigation potential, while NF retentate, enriched in these elements, was studied for its potential as a bioherbicide. The phytotoxicity of the NF retentate fraction on two crops (maize and flax) was evaluated on seedlings growth and chloroplast pigments content. In addition, the induced defense responses in maize and flax seedlings were investigated by measuring two parameters: the activity of the detoxification enzyme glutathione-S-transferase (GST) and the concentration of polyphenols, as a component of the antioxidant defense strategy in plants. Biomass, height, and chloroplast pigments content decreased progressively with increasing NF retentate concentration. Conversely, an increase in GST activity and polyphenol concentration was observed. These results highlighted the ability of OMW to induce an oxidative stress on maize and flax seedlings, triggering a defense response through GST and phenolic compounds. On the other hand, in vitro tests on the phytotoxicity of the NF retentate fraction on the common weed Sinapis arvensis were carried out. No germination was observed even with the lowest dilution applied, thus establishing the first data about the selectivity of potential OMW-derived bioherbicides. On the other hand, UF retentate and NF permeate treatments led to a significant increase in maize growth: these fractions could then be considered as a promising organic fertilizer for degraded agricultural soils, as well as an alternative water source for crops irrigation.

Growth Response of Wheat and Maize to Different Nitrogen Supply Forms under the Enrichment of Atmospheric CO2 Concentrations

Elevated atmospheric CO2 concentrations (eCO2) has become the main feature and cause of global change that could affect crop growth in many aspects, including physiological processes and morphological development in plants and nutrient cycling and nutrient uptake from the soil. Studying the responses of crop growth to different nitrogen (N) supply forms under elevated atmospheric CO2 concentrations can guide nutrient management strategies for agricultural production under future climate change scenarios. Few studies addressed the effect of eCO2 on N uptake and morphological development for plants. This study was conducted in the CO2-controlled light incubators based on the sand-pot incubation using wheat and maize as experimental plants. Six treatments were set with two different environmental CO2 concentrations (aCO2, 390 µmol mol−1; eCO2, 690 µmol mol−1) and three different N supply forms, including ammonium−N, nitrate−N and ammonium-nitrate with 1:1 ratio. The following results were obtained: (i) Wheat and maize seedlings, as nitrate-preferring crops, grew better under mixed N forms than under single N forms. For the single N supply treatment, seedlings with nitrate−N supply showed better growth than with ammonium. (ii) For wheat plants, seedlings with a single ammonium−N supply showed slender height and fewer tillers; seedlings with a single nitrate−N supply were characterized by slightly shorter plant height, more tillers, and higher aboveground biomass. (iii) Compared to the aCO2 group, wheat seedlings with the ammonium−N supply showed an increased maximum root length and a decreased carbon concentration in root exudates; wheat seedlings with a single nitrate−N supply under eCO2 showed a significant increase in biomass and a decreased carbon concentration in root exudates; wheat seedlings with a mixed N supply under eCO2 explored a significant increase in carbon concentration in root exudate and a relatively lower N concentration. (iv) For maize plants, seedlings with either single ammonium−N or nitrate−N supply did not show significant differences in most growing indices. Maize seedlings with a mixed N supply exhibited an increase in aboveground biomass and N concentration in root exudates compared to those with a single N supply. (v) Compared with the aCO2 group, maize seedlings with mixed N supply under eCO2 conditions exhibited significant increases in plant height, aboveground biomass, and N concentration in root exudates. Single ammonium−N supply was toxic to wheat and maize plants under eCO2 conditions. We recommend raising the ratio of ammonium-to-nitrate under mixed N supply to improve the coordination of carbon and N metabolism for efficient crop growth under climatic change conditions of elevated atmospheric CO2 concentration.

Water deficit aggravated the inhibition of photosynthetic performance of maize under mercury stress but is alleviated by brassinosteroids.

Mercury (Hg) significantly inhibits maize (Zea mays L.) production, which could be aggravated by water deficit (WD) due to climate change. However, there is no report on the maize in response to combined their stresses. This work was conducted for assessing the response and adaptive mechanism of maize to combined Hg and WD stress using two maize cultivars, Xianyu (XY) 335 and Yudan (YD) 132. The analysis was based on plant growth, physiological function, and transcriptomic data. Compared with the single Hg stress, Hg accumulation in whole plant and translocation factor (TF) under Hg+WD were increased by 64.51% (1.44mgkg-1) and 260.00%, respectively, for XY 335; and 50.32% (0.62mgkg-1) and 220.02%, respectively, for YD 132. Combined Hg and WD stress further increased the reactive oxygen species accumulation, aggravated the damage of the thylakoid membrane, and decreased chlorophyll content compared with single stress. For example, Chl a and Chl b contents of XY 335 were significantly decreased by 48.67% and 28.08%, respectively at 48h after Hg+WD treatment compared with Hg stress. Furthermore, transcriptome analysis revealed that most of down-regulated genes were enriched in photosynthetic-antenna proteins, photosynthesis, chlorophyll and porphyrin metabolism pathways (PsbS1, PSBQ1 and FDX1 etc.) under combined stress, reducing light energy capture and electron transport. However, most genes related to the brassinosteroids (BRs) signaling pathway were up-regulated under Hg+WD stress. Correspondingly, exogenous BRs significantly enhanced the maize tolerance to stress by decreasing Hg accumulation and TF, and raising activities of antioxidant enzyme, the content of chlorophyll and photosynthetic performance. The PI, Fv/Fm and Fv/Fo of Hg+WD+BR treatment were increased by 29.88%, 32.06%, and 14.56%, respectively, for XY 335 compared to Hg+WD. Overall, combined Hg and WD stress decreased photosynthetic efficiency by adversely affecting light absorption and electron transport, especially in stress-sensitive variety, but BRs could alleviate the inhibition of photosynthesis, providing a novel strategy for enhancing crop Hg and WD tolerance and food safety.

Estimating the genetic parameters of yield-related traits under different nitrogen conditions in maize.

Understanding the genetic basis responding to nitrogen (N) fertilization in crop production is a long-standing research topic in plant breeding and genetics. Albeit years of continuous efforts, the genetic architecture parameters, such as heritability, polygenicity, and mode of selection, underlying the N responses in maize remain largely unclear. In this study, about n = 230 maize inbred lines were phenotyped under high N (HN) and low N (LN) conditions for 2 consecutive years to obtain 6 yield-related traits. Heritability analyses suggested that traits highly responsive to N treatments were less heritable. Using publicly available SNP genotypes, the genome-wide association study (GWAS) was conducted to identify n = 237 and n = 130 trait-associated loci under HN and LN conditions, n = 164 for N-responsive (NR) traits, and n = 31 for genotype by N interaction (G × N). Furthermore, genome-wide complex trait Bayesian (GCTB) analysis, a method complementary to GWAS, was performed to estimate genetic parameters, including genetic polygenicity and the mode of selection (S). GCTB results suggested that the NR value of a yield component trait was highly polygenic and that 4 NR traits exhibited negative correlations between SNP effects and their minor allele frequencies (or the S value <0)-a pattern consistent with negative selection to purge deleterious alleles. This study reveals the complex genetic architecture underlying N responses for yield-related traits and provides candidate genetic loci for N resilient maize improvement.

Response of wheat and maize yields to different tillage practices across China: A meta-analysis

Tillage practice can change soil properties, regulate crop root development and nutrient availability, thus affecting crop growth and yield. However, the effect of no tillage (NT) and deep tillage (DT) on crop yield relative to conventional tillage (CT) under varied environmental and management conditions is unclear in China. We assessed the yield response of wheat and maize to NT and DT relative to CT based on collected field data (518 observations) with a meta-analysis. In general, NT led to negative yield response of both crops relative to CT, whereas maize presented a positive yield response (6.0 %) to NT in sandy soil, and crop yield responses to NT were not significantly different among environmental and management factors. DT significantly increased the yield of wheat (8.7 %) and maize (8.2 %) over CT. For wheat, the yield response to DT was similar across soil textures, climate conditions, experiment durations, N fertilizer rates, and residue managements; however, the interval DT every 2–3 years (13.2 %) and monoculture (13.9 %) increased yield response than the continuous DT (8.4 %) and double cropping system (8.9 %), respectively. The yield response of maize to DT was greater in semidry region (16.1 %) and under high N fertilizer rate (>300 kg N ha−1) (16.1 %), interval DT (12.4 %) compared with those in humid (7.5 %) and semi-humid (6.8 %) regions, low N fertilizer rates (<300 kg N ha−1) (6.9 %−7.5 %), and continuous DT (7.8 %), respectively; but other environmental and management factors did not affect its yield response. Overall, NT presented similar yield of wheat and maize to CT, while DT significantly enhanced their yields; this analysis revealed the crucial environmental and management factors influencing yield response to tillage practices in China, we also gave some suggestions on selecting appropriate tillage methods to realize high crop yield or/and agricultural sustainable development.

The quality and quantity response of maize (Zea mays L.) yield to planting date and fertilizers management

Cereal grains have the main role in human world food because of carbohydrates, proteins, lipids, vitamins, and minerals which affected by genetic and environmental conditions. Field experiment was conducted for two years using a split-plot arrangement in a randomized complete block design to study the effect of sowing date and organic and inorganic nutrients on maize yield and quality of oil in Shahirar, Tehran. The treatment consists of two sowing dates viz., on time date (July 15) and delayed sowing (August 15) in main plot and six fertilizer treatments viz., No fertilizer, Urea (200 kg N ha−1), farmyard manure (FYM) (200 kg N ha−1), vermicompost (200 kg N ha−1), Urea (50% N) + FYM (50% N) and Urea (50% N) + vermicompost (50% N). The outcome of field experiments revealed that on time planting recorded maximum oleic acid (18.68%) and while 200 kg N ha−1 through vermicompost recorded maximum oleic acid (17.38%) which was 12% higher than control. The highest seed yield was achieved in urea+vermicompost treatment (5570 kg ha−1). While highest oil content and linolenic acid was with FYM (200 kg N ha−1). The interaction effect showed that urea applied to maize sown on time had the highest oil yield. Linoleic and linolenic acid was less in maize which was sown late. It is concluded from study that application of urea alone or urea with vermicompost to maize sown in time can be recommended.

Responses of canopy functionality, crop growth and grain yield of summer maize to shading, waterlogging, and their combination stress at different crop stages

In the Huang-Huai-Hai region of China, continuous rain is the main meteorological constraint for summer maize, accompanied by stresses of both waterlogging and shading. To evaluate the independent and combined effects of shading and waterlogging on summer maize at different stages, a field experiment was performed to study the grain yield, crop growth, and canopy functionality of summer maize in response to waterlogging (W), shading (S), and their interaction for a 6 day period starting at the third leaf stage (V3), the sixth leaf stage (V6), and the tasseling stage (VT). Shading, waterlogging, and their combination stress (S+W) significantly decreased the grain yield of summer maize. Among these, the simultaneous stress induced greater yield losses than single stresses at any growth stage. The reduction of yield induced by waterlogging at early and late stages differed from 20–40 % to 3–16 %. Shading at VT stage induced most serious losses of grain yield. The grain yield of summer maize was closely related with the crop biomass accumulation. Shading, waterlogging, and their combination stress significantly decreased leaf area index resulting in serious reduction of the radiation interception. Besides, the leaf SPAD value and photosynthetic rate were also significantly reduced by the stresses, which led to notable reduction in radiation use efficiency (RUE) of summer maize. Thereby, the total accumulated crop biomass was decreased. Moreover, the biomass partitioning to ears was decreased. Accordingly, the 1000-kernel weight and kernels per ear were decreased by the stresses, leading to yield losses. This study explored the differential responses of radiation interception, canopy functionality, and RUE to waterlogging, shading, and their combined stress at different growth stage, furthering our understanding on the yield and growth for summer maize crops under persistent rainfall conditions.

Response of hybrid and landrace maize to foliar and root herbivore insects

Response of hybrid and landrace maize to foliar and root herbivore insects

The Roles of CDPKs as a Convergence Point of Different Signaling Pathways in Maize Adaptation to Abiotic Stress.

The calcium ion (Ca2+), as a well-known second messenger, plays an important role in multiple processes of growth, development, and stress adaptation in plants. As central Ca2+ sensor proteins and a multifunctional kinase family, calcium-dependent protein kinases (CDPKs) are widely present in plants. In maize, the signal transduction processes involved in ZmCDPKs' responses to abiotic stresses have also been well elucidated. In addition to Ca2+ signaling, maize ZmCDPKs are also regulated by a variety of abiotic stresses, and they transmit signals to downstream target molecules, such as transport proteins, transcription factors, molecular chaperones, and other protein kinases, through protein interaction or phosphorylation, etc., thus changing their activity, triggering a series of cascade reactions, and being involved in hormone and reactive oxygen signaling regulation. As such, ZmCDPKs play an indispensable role in regulating maize growth, development, and stress responses. In this review, we summarize the roles of ZmCDPKs as a convergence point of different signaling pathways in regulating maize response to abiotic stress, which will promote an understanding of the molecular mechanisms of ZmCDPKs in maize tolerance to abiotic stress and open new opportunities for agricultural applications.

Advances in deciphering salt tolerance mechanism in maize

Maize (Zea mays L.) is a global cereal crop whose demand is projected to double by 2050. Along with worsening of farmland salinization, salt stress has become a major environmental threat to the sustainability of maize production worldwide. Accordingly, there is an urgent need to decipher salt-tolerant mechanisms and facilitate the breeding of salt-tolerant maize. As salt tolerance is a complex trait regulated by multiple genes, and maize germplasm varies widely in salt tolerance, efforts have been devoted to the identification and application of quantitative-trait loci (QTL) for salt tolerance. QTL associated with ion regulation, osmotic tolerance, and other aspects of salt tolerance have been discovered using genome-wide association studies (GWAS), linkage mapping, and omics-based approaches. This review highlights recent advances in the molecular-level understanding of salt stress response in maize, in particular in (a) the discovery of salt-tolerance QTL, (b) the mechanisms of salt tolerance, (c) the development of salt-tolerant maize cultivars, and (d) current challenges and future prospects.

Lime and Vermicompost Application to Acid Soils and Their Effects on Maize Yield and Yield Components in Lalo Asabi District, West Wollega Zone, Oromia, Ethiopia

Soil acidity is one of the major yield-limiting factors for crop production worldwide, particularly on highly weathered and leached tropical soils. Different reports have indicated that there is significant soil acidity coverage in Ethiopia. In particularly, in the western part of the country, soil acidity is a well-known problem limiting crop production and productivity. As part of the solution to such a problem in soils, the combined application of lime and VC on maize has not been investigated in the area, in which maize was one of the potential cereal crops in the area. A field experiment was conducted at Lalo Asabi district in western Wollega during the 2020 cropping season to evaluate the responses of maize to the combined application of lime and vermicompost (VC). The experimental treatments were five rates of lime (CaCO3) (0, 25, 50, 75, and 100% of lime requirement (LR)) and three levels of vermicompost (0, 2.5, and 5 t ha-1). The treatments were arranged in factorial combinations in a randomized complete block design with three replications. One composite surface soil samples from a depth of (0-15 cm) was collected from the experimental field before the commencement of the experiment. Maize yield and yield components were measured following standard procedures. The yield components and yield results revealed the main effects of lime and VC showed a significant effect (p&lt;0.05) on the number of days to 50% tasseling and silking, ear height, number of cobs per plant, number of grains per cob, thousand grain weight, above ground biomass, and harvest index of maize. However, days to 90% physiological maturity, plant height, cob length and grain yield of maize were significantly affected (p&lt;0.05) by lime and VC interactions. Even though both were statistically equal, the combined application of lime at 100% LR + 5 t VC ha-1 yielded the highest grain yield (7.99 t ha-1) followed by the combined application of lime at 75% LR + 2.5 t VC ha-1 whereas the lowest grain yield (2.97 t ha-1) from control plots. The results of economic analysis indicated that the combination of lime at 75% LR + 2.5 t VC ha-1 showed a marginal rate of return of 2322.74%, with the highest net benefit of 49980 Ethiopian Birr compared to other treatments. This study indicates combined use of lime and VC could ameliorate the adverse effect of soil acidity, and application of 75% LR + 2.5 t VC ha1 enhances grain yield and produces the highest net benefit of maize grown on acidic soil of the Lalo Asabi district.

A linear profit function for economic weights of linear phenotypic selection indices in plant breeding

AbstractThe profit function (net returns minus costs) allows breeders to derive trait economic weights to predict the net genetic merit (H) using the linear phenotypic selection index (LPSI). Economic weight is the increase in profit achieved by improving a particular trait by one unit and should reflect the market situation and not only preferences or arbitrary values. In maize (Zea mays L.) and wheat (Triticum aestivum) breeding programs, only grain yield has a specific market price, which makes application of a profit function difficult. Assuming the traits’ phenotypic values have multivariate normal distribution, we used the market price of grain yield and its conditional expectation given all the traits of interest to construct a profit function and derive trait economic weights in maize and wheat breeding. Using simulated and real maize and wheat datasets, we validated the profit function by comparing its results with the results obtained from a set of economic weights from the literature. The criteria to validate the function were the estimated values of the LPSI selection response and the correlation between LPSI and H. For our approach, the maize and wheat selection responses were 1,567.13 and 1,291.5, whereas the correlations were .87 and .85, respectively. For the other economic weights, the selection responses were 0.79 and 2.67, whereas the correlations were .58 and .82, respectively. The simulated dataset results were similar. Thus, the profit function is a good option to assign economic weights in plant breeding.

Optimal Sowing Windows under Rainfall Variability in Rainfed Agriculture in West Africa

Climate change is exacerbating adverse impacts of water stress in rainfed agriculture. This paper seeks to identify safe sowing windows for smallholder farmers in the Sudanian region of West Africa (WA). We hypothesize that the traditional focus on the onset of the season to start sowing leads to crop losses in years of high rainfall intermittency. AquaCrop, an FAO crop model, is used to simulate the yield response of maize (Zea mays L.) to sowing dates ranging from the 1st of May to the 30th of November at 20 locations in WA. We find that sowing directly after the first rains carries a higher risk of water stress, hampering crop development due to insufficient buildup of soil water storage to overcome dry spells. Based on three years of data per station on average, we identify safe sowing windows across the Sudanian region that secure optimal yield in 97% of all cases. We find that delaying sowing to mid-June (savanna and western part of the region) and to July (semi-arid region) ensures optimal yields. Of the three commonly applied local onset approaches covered in our evaluation, only LO10mm (10 mm/day on four consecutive days) achieves a similar yield result. The advantage of the safe window approach is that it is accessible for smallholders, who in many cases do not have access to local rainfall information.

Identification and characterization of waterlogging-responsive genes in the parental line of maize hybrid An'nong 876.

Waterlogging stress is an important abiotic stress that adversely affects maize growth and yield. The mechanism regulating the early stage of the maize response to waterlogging stress is largely unknown. In this study, CM37 and cmh15 seedlings were treated with waterlogging stress and then examined in terms of their physiological changes. The results indicated that inbred line cmh15 is more tolerant to waterlogging stress and less susceptible to peroxide-based damages than CM37. The RNA sequencing analysis identified 1,359 down-regulated genes and 830 up-regulated genes in the waterlogging-treated cmh15 plants (relative to the corresponding control levels). According to the Gene Ontology analysis for the differentially expressed genes (DEGs), some important terms were identified which may play important roles in the response to waterlogging stress. Moreover, enriched Kyoto Encyclopedia of Genes and Genomes pathways were also identified for the DEGs. Furthermore, the substantial changes in the expression of 36 key transcription factors may be closely related to the maize in response to waterlogging stress. This study offers important insights into the mechanism in regulating maize tolerance to waterlogging stress, with important foundations for future research.

A Simple Semi-hydroponic System for Studying Iron Homeostasis in Maize.

Hydroponic-based systems for plant growth allow control of the nutrients that plants take up through the provided nutrient solution. Different formulations of nutrient solutions enable the study of nutrient deficiencies in plants. Here we describe a procedure for setting up a simple semi-hydroponic system to grow maize seedlings. The system can be set up on a small or large scale, depending on the number of individuals studied. A modified nutrient solution is used for growing maize seedlings in iron-replete and iron-depleted conditions. This setup allows for studies of iron-deficiency responses in maize.

Identification and Characterization of ZF-HD Genes in Response to Abscisic Acid and Abiotic Stresses in Maize

The zinc finger homeodomain (ZF-HD) genes belong to the homeobox gene family, playing critical roles in flower development and stress response. Despite their importance, however, to date there has been no genome-wide identification and characterization of the ZF-HD genes that are probably involved in stress responses in maize. In this study, 24 ZF-HD genes were identified, and their chromosomal locations, protein properties, duplication patterns, structures, conserved motifs and expression patterns were investigated. The results revealed that the ZF-HD genes are unevenly distributed on nine chromosomes and that most of these genes lack introns. Six and two ZF-HD genes have undergone segmental and tandem duplication, respectively, during genome expansion. These 24 ZF-HD transcription factors were classified into six major groups on the basis of protein molecular evolutionary relationship. The expression profiles of these genes in different tissues were evaluated, resulting in producing two distinct clusters. ZF-HD genes are preferentially expressed in reproductive tissues. Furthermore, expression profiles of the 24 ZF-HD genes in response to different kinds of stresses revealed that ten genes were simultaneously up-regulated under ABA, salt and PEG treatments; meanwhile four genes were simultaneously down-regulated. These findings will pave the way for deciphering the function and mechanism of ZF-HD genes on how to implicate in abiotic stress.

Response of waxy maize (Zea mays L. var. ceratina Kulesh) leaf photosynthesis to low temperature during the grain-filling stage.

Low temperature (LT) during the grain-filling stage is an important factor that affects the source-sink relationship and leads to yield loss in maize (Zea mays L). In this study, field and pot trials were conducted to investigate the effects of LT during the grain-filling stage on leaf photosynthesis, antioxidant system, hormones, and grain yield of waxy maize cultivars Suyunuo 5 (S5) and Yunuo 7 (Y7). The results showed that LT treatment inhibited the chlorophyll biosynthesis and reduced the photosynthetic pigment levels during grain-filling stage. Ribulose-1,5-bisphosphate carboxylase and phosphoenolpyruvate carboxylase activities, photosynthetic rate, transpiration rate, and stomatal conductance decreased under LT treatment during the grain-filling stage. Furthermore, LT treatment increased the contents of malondialdehyde and reactive oxygen species, and decreased the activities of catalase, superoxide dismutase, peroxidase, and ascorbate peroxidase in the ear leaves, which accelerated the oxidative damage of leaf. The LT treatment also raised abscisic acid content and reduced indole acetic acid content in the ear leaves during grain-filling stage. The results of field and pot trials were verified by each other, but the field effect was greater than that of pot. Overall, LT treatment reduced the waxy maize dry matter accumulation after silking by affecting the physiological and biochemical processes of leaves, and ultimately decreased grain yield.

Manejo de nitrogênio no milho cultivado em segunda safra no sudoeste Goiano

ABSTRACT Nitrogen (N) fertilizer management is a key factor in the success of maize crops. The objective of this work was to evaluate the response of second-crop maize to N applied exclusively as topdressing or at planting + topdressing. Five experiments were conducted in areas in southwestern Goiás in 2019 and 2020 to evaluate N application rates of 0 and 30 kg ha-1 at planting, combined with five N rates applied as topdressing at the maize V3 stage over a total of 0, 75, 150, 225, and 300 kg ha-1. Dry matter production in the V6 or V9 stage and yield parameters at harvest were evaluated. N application did not affect the number of grain rows per ear but increased the number of grains per row and, particularly, grain weight. The crop responded positively to increases in the total N rate in 4 of the 5 experiments: in 1 of these experiments, N fertilizer application at planting contributed to an increase in the efficiency of topdressing fertilization, resulting in a higher maize yield with a lower total N rate; in the other 3, a positive maize response to N occurred when total N was applied as topdressing at V3. However, the highest mean maize grain yield (8,233 kg ha-1) was found in the trial that showed no response to N fertilizer application - probably due to the better chemical fertility conditions of the area combined with an adequate distribution of rainfall, considering the multiple factors involved in N application recommendations.

Insights into physio-biochemical responses of maize to salt shock stress and removal of the stress at the whole-plant level

Insights into physio-biochemical responses of maize to salt shock stress and removal of the stress at the whole-plant level