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Plant Growth-Promoting Rhizobacteria (PGPR) plays a crucial role in enhancing plant health, while Burkholderia sp. has been identified and has potential as a promising PGPR for maize plants. Recognizing the essential role of PGPR in plant health, this study explores how L-TRP addition might improve PGPR performance for better plant growth. Employing a completely randomized design, the study assesses the effects of Burkholderia sp. as PGPR on maize growth across three treatment groups: PGPR with L-TRP, PGPR without L-TRP, and a control group. The evaluation focuses on plant growth metrics, plant hormone production (auxin and gibberellin), and siderophore activity to gauge plant iron availability. Statistical analysis highlights that L-TRP supplementation notably increases auxin production in the PGPR + L-TRP group, surpassing the PGPR without L-TRP and control groups. Although both PGPR treatments elevate gibberellin levels compared to the control, auxin increase is the most significant outcome, indicating no substantial difference in gibberellin levels between the two PGPR groups. Enhanced siderophore production suggests improved iron assimilation for plants. The findings demonstrate that L-TRP supplementation with PGPR, particularly Burkholderia sp., effectively boosts maize growth, primarily through increased auxin and siderophore production. This combination presents a promising strategy for augmenting agricultural yields, especially for maize productivity, by leveraging the synergistic effects of soil microbes and nutrient supplementation.

Multifunctional phosphate solubilizing microorganisms can contribute to reducing phosphorus doses without affecting the grain yield of crops. The aim of this work was to evaluate agricultural production systems involving soybean-maize and soybean-rice successions, inoculation of beneficial microorganisms and application of phosphorus doses with a view to sustainable intensification of agriculture and soil health and fertility in the Cerrados region. The experimental design was a randomized block design in a 2x4 factorial scheme with four replications. The treatments were composed of the combination of two phosphorus doses, 50% (45 kg ha-1 of P2O5) and 100% (90 kg ha-1 of P2O5) of the recommended dose with four uses of multifunctional microorganisms: 1. BRM 32111 (Burkholderia sp.), 2. BRM 32114 (Serratia marcescens), 3. co-inoculation (BRM 32111 + BRM 32114), and 4. control (no application of microorganisms). The microorganisms provided significant increases in the 100-grain weight and grain yield of soybeans, dry matter and nutrient accumulation of rice and maize, reduction of phytopathogenic fungus propagules, and increased accumulation of nutrients and activity of the enzymes Betaglicosidase and Arilsulfatase in the soil. Applying 50% phosphorus reduced the 100-grain weight and grain yield of soybean, dry matter and nutrient accumulation of rice, propagules of Trichoderma spp., and the nutrients in the soil. The soybean-maize succession showed higher levels of Arylsulfatase than the soybean-rice succession. The highest soybean yields were obtained by applying BRM 32114 with 50% and co-inoculation with 100% phosphorus.

Hot springs situated at high altitudes is a kind of remarkable ecosystem for the exploration of microbial flora. It was hypothesized that hot springs can harbor bacteria with plant growthpromoting and exopolysaccharides (EPS) producing ability that can favour the growth of plants. For the investigation of this hypothesis, seven EPS producing bacterial isolates were isolated from a water sample of hot water spring of Tattapani, Azad Kashmir and characterized morphologically and biochemically. Three out of seven isolates (BE1, BN1 and BN3) showed significant production of EPS (14-15 mg / 100 ml). Growth kinetics study revealed that optimum EPS production was attained at pH 9, with fructose as a carbon source and peptone as a nitrogen source. Inoculation of these isolates caused augmentation in seed germination (27-38 %), shoot length (27-35 %), seedling length (10-14 %), number of roots (12-25 %) of Zea mays (variety-MMRI yellow) seedlings and significant rise in auxin (28-51 %) and soluble protein content (50-68 %) as compared to non-inoculated treatment. Alcian blue staining unveiled the good colonization potential of these isolates on inoculated roots. Bacterial isolates were identified as Ochrobactrum intermedium (BE1), Bacillus pumilus (BN1) and Enterobacter cloacae (BN3), respectively through 16S rRNA analysis. Bacterial strain BN3 showed promising results for plant growth promotion along with EPS production. Fourier-transform infrared (FTIR) spectroscopy of EPS produced by strain BN3 revealed the complex composition of EPS. We concluded that hot springs can be the possible home for EPS producing bacteria with plant growth promotion capability.

In order to explore the effect of exogenous 24-epibrassinolide (EBR, 0.1 µM) application on photosynthetic parameters in response to different light intensities and CO2 concentrations in maize seedlings under NaCl stress (180 mM), this study investigated the light response curve, CO2 response curve, and diurnal variation of photosynthesis of maize seedlings under NaCl stress. Maize cv. Jinlai 318 was used as the material, and the leaves were sprayed with 0.1 µM EBR. Net photosynthetic rate (PN), stomatal conductance (gs), intercellular CO2 concentration (Ci), and transpiration rate (E) were determined. The results showed that the light response curve, CO2 response curve, and diurnal variation trend under the four treatments (180 mM NaCl, 0.1 µM EBR, 180 mM NaCl with 0.1 µM EBR, pure water) were similar. The light saturation point of the leaves under NaCl stress was the lowest (about 1 031 mol m-2 s-1), and that in the control group (without stress) was the highest (about 1 344 mol m-2 s-1). When the light saturation point was reached (1 030 -1 350 mol m-2 s-1), the maximum PN under NaCl stress was the lowest (about 15.15 μmol m-2 s-1), while that under EBR treatment, it was the highest (about 19.86 μmol m-2 s-1). NaCl stress significantly reduced chlorophyll a, chlorophyll b, and carotenoid content and chlorophyll a/b ratio, while chlorophyll content significantly increased after EBR treatment. These results showed that exogenous EBR could effectively alleviate the damage to maize seedlings under NaCl stress, delay the light saturation phenomenon, and improve the photosynthetic capacity of maize.

El objetivo fue identificar las cepas, la cantidad y la diversidad de hongos presente en tortillas de 14 razas de maíz. Se determinó el peso del complejo de hongos (PCH) y la identificación de los hongos del mismo, así como características del grano (índice de flotación), nixtamal (humedad de nixtamal y humedad de masa) y tortilla (humedad de tortillo a las 24 y 48 h). A los datos se les realizó un análisis de varianza. Todas las variables presentaron diferencias significativas (p ≤ 0.05). Para el PCH los mayores promedios estadísticamente diferente fueron las razas Naltel de altura (0.69 g) y Arrocillos amarillo (0.68 g) por tortilla. La raza Chalqueño tuvo el mayor número de hongos en el complejo (Aspergillus flavus, Mucor sp., Penicillium sp., Rhizopus oryzae, Acremonium sp. y Alternaria sp.); con diferencia del hongo Penicillium sp., la raza Cónico fue la segunda mejor, y en Pepitilla solo se identificó el hongo Acremonium sp. Para la humedad de nixtamal y de masa la raza Pepitilla obtuvo los mejores valores, con un 49.7 y 60.9%, respectivamente. Se tuvieron diferencias del 65.2% en el PCH entre las razas evaluadas, presentando el mayor y menor peso las razas Naltel de altura y Chalqueño, respectivamente.

The Spodoptera frugiperda, is one of the most deleterious pests of popcorn and the identification of resistant genotypes is determinant in breeding programs. The objective of this study was to select popcorn genotypes resistant to S. frugiperda and the key traits related to the identification of resistance. The popcorn varieties UEM J1, Composto Márcia, Arachida, Composto Gaúcho, and Zapalote Chico (resistant check) were evaluated in a completely randomized design with 100 replications. The experimental unit consisted of one Petri dish, containing plant material and a caterpillar The following traits were evaluated: larval stage duration (LSt), food intake weight(IW), final larva weight (FW), mean larva weight (MW), feces (F), assimilated (A) and metabolized food weight (M), relative consumption rate (RCR), relative metabolic rate (RMR), relative growth rate (RGR), conversion efficiency of ingested food (CEI), apparent digestibility (AD), conversion efficiency of digested food (CED), and leaf area consumed (LAC). The diagnosis of multicollinearity, analysis of canonical variables, genetic divergence, hierarchical clustering, factor analysis and canonical correspondence analysis were carried out to perform multivariate analysis. After the multicollinearity test, the traits FW, IW, RCR, AD, and LAC were maintained for further analysis. The traits IW, FW and AD were determinant in the resistance by antixenosis expressed by the varieties Zapalote Chico and Arachida, for the varieties Composto Gaúcho and Composto Márcia the determining characteristics were RCR and LAC and for the variety UEM J1 the variable LAC showed greater importance. Variety Arachida was considered resistant to S. frugiperda by antixenosis and can be used in the future as a source of favorable alleles to breed resistant popcorn hybrids. The traits relative consumption rate, apparent digestibility and leaf area consumed were considered key traits in the identification of resistance against S. frugiperda in popcorn genotypes.

Context: Intercropping maize with tropical forages is known to provide multiple benefits for the agricultural sustainability in the Brazilian savanna. Despite that, more studies are needed to define strategies to improve soil quality and increase crop yield of subsequent crops. Aims: This study aimed to evaluate the impacts of cultivating maize in monoculture or in double- and triple-intercropping with brachiaria and crotalaria on the chemical and microbiological attributes of soil, nutritional status of soybean, and the productivity of soybean and millet in succession in the cerrado of eastern Maranhão. Methods: The intercropping systems implemented in 2017 were as follows: maize (Zea mays) + Urochloa ruzizienses (brachiaria); maize + Crotalaria juncea (crotalaria); maize + brachiaria + crotalaria; and monoculture maize as a control. In 2018 and 2019, soybean and millet were cultivated on the same plots. Key results: The triple-intercropping promoted immediate improvement in the biological and chemical attributes of the soil, especially when compared with monoculture maize. Intercropping maize with brachiaria, with or without crotalaria, increased soybean productivity by 21% and millet by 44% in the subsequent year, compared with monoculture maize system. Intercropping maize with brachiaria, with or without crotalaria, increased the leaf concentrations of nitrogen, potassium, magnesium, and sulfur of the subsequent soybean crop, suggesting improved nutrient cycling with intercropped forages. Conclusions: Intercropping maize + forage, especially brachiaria, can be recommended for crop rotation and succession systems in the Brazilian savanna. Implications: These results quantified the benefits of crop rotation following intercropping with maize and forage, which can be an alternative for farmers in the Brazilian savanna. The sustainability of grain production systems is especially challenging under tropical conditions, where high temperatures and moisture in the rainy season accelerate biogeochemical processes and soil degradation. Despite the lack of technological options for enabling sustainable grain production systems in agricultural frontiers, in this study, we showed that intercropping maize with braquiaria and crotalaria increases soil microbial activity, nutrient cycling, and grain yield of subsequent soybean and millet crops. Our results have provided a feasible option for sustainable grain production systems in eastern Maranhão. [ABSTRACT FROM AUTHOR]

Fodder crops have to compete with those of field crops, and the majority of farmers are smallholders in the circumstances of Pakistan. Therefore, this study was planned to search for the best maize hybrid which would serve dual purposes, i.e. for grain production as well as its later usage as fodder and silage. So, seven maize hybrids most commonly grown in the vicinity were selected and compared for their forage production. Maize hybrids were sown on ridges followed by all cultural operations as carried out by farmers. At harvest, plant morphological parameters were measured before ensiling the whole maize plant. For ensiling, fodder was harvested and chopped into 3-4 cm long discs using a chaff cutter. The fodder was then transferred to plastic jars, pressed hard to remove air, sealed, and kept airtight for 40 days. Samples were taken after the ensiling period and subjected to different quantity and quality parameters. It was observed that Monsanto DK-6789 showed the best performance in agronomic; plant height at harvest, number of leaves per plant, dry weight per plant, fresh forage yield at harvest, and dry matter yield, and quality parameters; crude protein, fiber, and total ash percentage. DK-6789 also showed superiority in lactic acid, pH, dry matter, crude protein, neutral detergent fiber, acid detergent fiber, hemicellulose, and cellulose. Therefore, this maize hybrid may be recommended for grain production in the irrigated areas, while its leftovers can be utilised as forage or ensiled for quality silage.

Con el propósito de determinar la calidad en semillas beneficiadas de Zea mays, se evaluó el comportamiento de los indicadores de calidad de cuatro variedades recibidas del Laboratorio Provincial de Semillas de Cienfuegos, correspondientes al primer semestre de 2021. Para determinar la calidad física de las mismas y el diagnóstico fitosanitario se estimaron las variables cantidad de semillas puras, materia inerte, porcentaje de germinación, plántulas normales y anormales, cantidad de semillas frescas, puras y muertas según la Norma Cubana NC: 70:01, perteneciente a los estándares ISTA. La germinación mostró diferencias significativas entre las variedades evaluadas. Las muestras de semillas híbridas exhibieron porcentajes de germinación inferiores al resto. La cantidad de materia inerte en el diagnóstico fitosanitario fue mayor para MAIG-5461 seguido del híbrido AME-15. Sin embargo, el porcentaje de semillas puras fue superior al 98% en todas las variedades, lo que indica que las muestras están libres de cualquier mezcla de otras semillas y en menor cantidad de materia inerte.

The food industry is very interested in high-yield ingredients to enrich and develop new products that have an affordable value for the population. This work aimed to determine the correlations and contrasts between grain physical and agronomic traits of conventional and transgenic corn hybrids cultivated in the first crop season. The experiments were installed in the 2017/18, 2018/19, and 2019/20 crop seasons in Guarapuava - PR. The experimental design was a randomized block design with eight hybrids (SUPREMO VIP, SUPREMO, P30F53VYH, P30F53, P3456H, P3456, DKB290PRO3, and DKB290) and three replications. The agronomic traits, such as the percentage of rot grains, 1000-grain mass, and grain yield, also the physical traits of grains for industrial purposes, such as grits, germ, vitreousness, flotation, and hectoliter weight, were evaluated. There is a positive correlation between grits and flotation. The choice of hybrids for the food industry based on vitreousness positively favors flotation. The grits showed a positive correlation with hectoliter weight and a negative correlation with the incidence of rot grains. Vitreousness was influenced by the choice of conventional or transgenic hybrid and crop season. The environments of the crop seasons influence the grain yield, 1000-grain mass, and rot grain incidence of conventional and transgenic corn hybrids.

Maize has a high nutritional requirement, especially regarding NPK fertilization. However, conventional fertilization with these nutrients presents a high loss potential, mainly by volatilization, leaching, adsorption, and fixation, which may reflect on the development and yield of maize plants. Using fertilizers with increased efficiency seeks to mitigate these limitations, reducing potential losses due to gradual nutrient release. This study aimed to compare the nutrition, growth, and production of maize plants subjected to different doses and special NPK fertilizers fully applied at planting and their residual effect on the soil. It was a randomized block design in a 3x4 factorial scheme with four replications. The first factor consisted of conventional mineral, polymer-coated, and organomineral + PGPB fertilizers. The second factor included doses of 0, 60, 90, and 120 kg ha-¹ of NPK. The study evaluated vegetative growth, foliar nutrition (N, P, and K), yield growth components, productivity, profitability, and residual K content in the soil after cultivation. The conventional mineral fertilizer produced more dry biomass in the aerial part. Profitability was similar between conventional and special fertilizers. However, the latter performed better overall in vegetative and productive growth, showing a potential reduction of the applied doses without compromising grain yield, especially in organomineral + PGPB fertilization. This treatment also presented a higher residual effect of K on the soil.

Maize silage has been used as a forage reserve strategy for critical periods or continuous use in animal feed. However, new genotypes and their potential must be identified. Thus, this study aimed to evaluate the potential of maize genotypes for silage and grain in one off-season in the midwest region of Brazil, under limited water and frost, and select them for this dual purpose (silage and grain) using the GT Biplot tool. The experiment was performed at Embrapa Western Agriculture in the autumn-winter season of 2021 in Dourados, Mato Grosso do Sul, Brazil. The experimental design consisted of randomized blocks of six maize genotypes (BRS1010, KWS9606, 1P2224, 1Q2383, BRS3046, and CAPO) with five replications under no-tillage. Silage points were evaluated at harvest when the grain milk line was at ¾ and maize grains at the maturation stage (dry plant). The 1P2224 and 1Q2383 maize genotypes present silage (high green and dry biomass) and grain yield potential. The GT Biplot tool identified the 1P2224 genotype as superior and suitable for cultivation or as a parent in a breeding program in the midwest region of Brazil for silage and grain yield evaluations of one off-season under limited water and frost.

Although fullerene (C60) has attracted great interest as a carbon-based nanomaterial with unique properties, today, little is known about the interaction of its water-soluble derivates, including fullerenol with higher plants. Here, we investigated how fullerenol [C60(OH)22-24] affects Zea mays, as a Strategy II plant, depending on its iron status. Iron deficiency chlorosis is a common nutritional disorder affecting plants. Maize plants were grown hydroponically, either with [+FeII (ferrous) or +FeIII (ferric)] or in Fe-free (-FeII and -FeIII) nutrient solution and with or without a fullerenol supply. Fullerenol affected plants differently depending on their Fe status. The beneficial effects of fullerenol were observed in the FeII-deprived plants, including successful suppression of plant Fe-deficiency chlorosis mainly in the younger (basal and middle) region of the leaf blade. This region expressed more severe chlorosis as compared with the older (apical) region of the leaf blade. These changes were accompanied by a significant increase in leaf active Fe and lowering the root apoplastic Fe, suggesting that fullerenol may enhance Fe mobilization in the roots, helping to alleviate Fe deficiency chlorosis. By contrast, there were no observable effects in the FeIII-deprived plants being significantly lower in the root apoplastic Fe as compared with the FeII-deficient plants. Additionally, fullerenol did not affect the Fe-sufficient plants, irrespective of the Fe species (FeIII-EDTA or FeII-EDTA) used as Fe-sources. Our results provide new evidence for the beneficial role of Fe-fullerenol interactions in the enhancement of gramineous plant tolerance to Fe deficiency conditions, which are one of the major limiting factors for crop production all over the world.

The impact of persisting herbicide residues on succeeding crops is of great concern to farmers because even the presence of very low concentrations can inhibit growth of crop and cause crop reduction. Furthermore, wastewater irrigation can lead to cadmium accumulation in soils. Thus, the co-occurrence of low amounts of herbicide residues and cadmium within agricultural fields are difficult to avoid. How the combination of these two pollutants affect plant metabolites remains to be elucidated and thus warrants investigation. Maize seeds were planted in soil that had been sprayed with chlorsulfuron and Cd, then we studied the effects of exposure to the herbicide chlorsulfuron (0.001, 0.003, 0.005, 0.008, and 0.010 mg kg-1) and cadmium (as 5.0 mg kg-1 CdCl2) on maize seedlings by utilizing nuclear magnetic resonance (NMR) after 21 d. Principle component analysis of 1H NMR spectra clearly discriminated between control and treatment groups. Compared with chlorsulfuron-only treatments, treatments using both contaminants showed higher content of phenolic acids, aspartic acid, choline, β-galactose, and α-glucose in the seedlings. Contrary to previous reports, we found larger pools of branched-chain amino acids in seedlings exposed to chlorsulfuron and CdCl2. These findings indicate that CdCl2 did not aggravate the effects of chlorsulfuron on maize seedlings metabolites. CdCl2 elicited significant changes in plant metabolism at a concentration that did not impair plant growth. Moreover, chlorsulfuron did not inhibit branched chain amino acid synthesis.

Maize is the second largest agricultural crop in Brazil. It reaches high yields as supported by the intensive use of technologies, particularly mineral fertilization, which is normally costly. To lower production costs and improve crop productivity on small farms, the present study tested the efficiency of poultry litter biochar as a source of nutrients in the initial growth of BRS 2022 maize by the ‘diagnosis by subtraction’ method. The study was carried out in a greenhouse, using a completely randomized experimental design with a factorial arrangement (7×3). The following treatments were tested: complete nutrient solution (N, P, K, Ca, Mg, S, B, Cl, Cu, Fe, Mn, and Zn); complete nutrient solutions with omission of only nitrogen (-N), phosphorus (-P), potassium (-K), calcium (-Ca), and magnesium (-Mg); and complete absence of nutrients and three increasing rates of biochar (0, 5, and 10 t ha-1). Absence of nutrients with biochar rates significantly influenced the growth and dry biomass production variables of the maize plants. Except for stem diameter and the ratio between shoot and root dry biomass, all variables were influenced by the interaction between nutrients and biochar rates. Nutrient omission limited maize growth; however, the application of biochar reduced these limitations and significantly improved all analyzed variables. In the treatments without fertilizer, maize growth was very low, with generalized symptoms of deficiency that would decrease with the application of biochar. Even in the treatment with complete fertilization, which showed some slight visual symptoms, these decreased with the application of biochar.

The cultivation of special corns, such as baby corn, has had a positive influence on the economy of the country. Despite its importance, there is still a need for studies aimed at increasing production and planting areas of the crop. Phytosanitary studies are of particular interest, as the cultivation of such crops is susceptible to a series of pathogens, such as Bipolaris maydis, Exserohilum turcicum, and Puccinia polysora. The use of resistant cultivars is the most effective way to prevent the occurrence of these diseases. Thus, the present study aimed to identify popcorn lines that have the potential for baby corn production and are resistant to the main leaf diseases that affect the crop. The experiment was conducted in randomized blocks with four replications of 30 lines in each area, during two planting seasons. The area was located at the Federal Institute of Espírito Santo (IFES) Campus of Alegre, situated in Rive district, Espírito Santo State, Brazil. Using the obtained data, the area under the disease progress curve was obtained. Subsequently, analysis of the joint variance of the data was conducted, and when a significant effect was found, a grouping of means test was conducted. The Mahalanobis distance for each pair of lines was also calculated, and the genetic distance matrix was used to construct a dendrogram using the UPGMA method. Considering the averages obtained for the three diseases (Southern corn leaf blight, Northern corn leaf blight, and Southern rust), lines L61, L63, L65, L683, L684, L685, L691, L694, and L695 were identified as possible donors of resistance alleles for multiple diseases. Multivariate analysis efficiently grouped the lines L61, L63, L684, L685, and L691, which are described as most resistant in the univariate analysis.

The fertiliser that is applied between maize (Zea mays L.) plants via furrow application cannot be completely absorbed and used because of the wide planting space, resulting in fertiliser wastage and soil pollution. To address this issue, we proposed an intermittent fertilisation method for single maize plant seeding, and designed a fertilisation device that can control the intermittent timing and duration of fertiliser application. A simple indoor bench test was done to verify the feasibility of the device. A synchronised control model of the seed and fertiliser was also established. Thus, a quantitative precision intermittent fertilisation system for a single maize plant was developed. The technique was integrated and applied in a current mainstream quantitative precision seeder and fertiliser feeder for maize in field trials. The trial results showed that the average centre distance between the seed and the fertiliser was 5–8 cm and the qualification rate was >90%. The effective length of fertilisation was about one-third of plant spacing, and the largest coefficient of variation was 12.37%. In conclusion, the present quantitative precision interval fertilisation system can feed and apply fertiliser to the predetermined fertiliser site of maize plants, realising the 'one seed and one fertiliser' seeding and fertilisation mode, which reduced the fertiliser application amount and increased the fertiliser utilisation rate. Fertiliser applied between maize plants by furrow application cannot be totally absorbed and used because of the wide planting space. To solve this problem, an intermittent fertilisation method for a single plant was proposed for maize seeding, and a synchronised control model of the seed and fertiliser was established and applied. The methodology of 'one seed and one fertiliser' reduced the fertiliser application amount and increased the fertiliser utilisation rate. [ABSTRACT FROM AUTHOR]

A utilização de fontes nitrogenadas que reduzam perdas de N pode ser uma estratégia de manejo adequada para aumentar a sustentabilidade econômica e ambiental no cultivo do milho. Este trabalho foi conduzido com o objetivo de avaliar os efeitos de fontes e doses de nitrogênio sobre a produtividade de grãos do milho e a lucratividade da lavoura. O experimento foi conduzido a campo, em dois anos agrícolas, num Nitossolo Vermelho de textura argilosa. O delineamento experimental foi de blocos ao acaso, dispostos em parcelas subdivididas. Na parcela principal foram testadas quatro fontes de N: ureia convencional, ureia protegida, ureia com inibidor de nitrificação e ureia com inibidor de urease. Nas subparcelas foram testadas quatro doses de nitrogênio: 0, 140, 280 e 420 kg de N ha-1. As quatro fontes de fertilizantes nitrogenados não apresentaram diferenças no rendimento de grãos. A produtividade de grãos variou de 3,2 a 15,9 Mg ha-1. Ela apresentou uma resposta quadrática ao aumento da dose, independentemente da fonte de N. As doses teóricas que otimizaram a produtividade de grãos foram de 407 e 411 kg N ha-1 em 2016/2017 e 2017/2018, respectivamente. Os maiores índices de lucratividade foram obtidos pela aplicação das doses de 378 kg de N ha-1 com ureia convencional em 2016/2017 e 278 kg de N ha-1 de ureia com inibidor de uréase em 2017/2018.

The succession of soybean/maize has been largely adopted. Storm damage and crop problems can lead to grain loss, generating maize ear fragments or even whole ears that remain in the soil and still display germination viability, resulting in the occurrence of volunteer plants. In this context, the present study aimed to evaluate the interference of voluntary maize plants on soybean and investigate the susceptibility of maize hybrids to pre-emergence herbicides. In the first step, an experiment was performed evaluating the influence of voluntary maize plant density and spatial distribution on soybean. The experiment was performed in a randomized completely block design (RCBD) with four replications, with treatments disposed in factorial arrangement (2 x 4) + 1. The first factor corresponded to the spatial distribution of maize plants: row or in between soybean rows; while the second factor adopted four infestation densities of maize plants m-2: 4, 8, 12, and 16. The additional treatment consisted of a control without maize plants. For the second step, an experiment was conducted in two locations aiming to determine the efficacy of pre-emergence herbicides in the control of voluntary maize. Both experiments were installed in RCBD in a split-plot scheme with four replications. Fomesafen, lactofen, sulfentrazone, chlorimuron-ethyl, diclosulam, flumetsulam, imazethapyr, clomazone, metribuzin, [sulfentrazone + diuron], [imazethapyr + flumioxazin], and a control without herbicide application were evaluated in the main plot. In each subplot, the maize hybrids DKB310 PRO3™ and DKB390 PRO3™ were evaluated. No influence on the position of voluntary maize on the soybean yield was observed. The presence of the maize population led to a progressive decrease in soybean yield, ranging up to 86%, at 16 plants m-2. DKB390 displayed a stand reduction of 82.88% after the use of diclosulam. Diclosulam led to better results regarding maize plant decreases for both hybrids.

Maize is an important crop and its nitrogen use efficiency (NUE) has been an issue for plant scientists and breeders for many years. To meet the demand of genetic diversity in cultivating local elite maize cultivars, researchers need to isolate germplasms with a high NUE. In this study, 30 maize inbred lines were screened under hydroponic conditions, and three inbred lines that tolerate low nitrogen concentration were identified. A comparative analysis of genes involved in N uptake, transport, and assimilation between two lines with different tolerances revealed that the low-nitrogen-tolerant inbred line MBST exhibited higher expressions of nitrate and ammonium transporters, especially ZmNRT3.1B, than less tolerant B73. This suggests that the MBST line had a more efficient high-affinity transporter system. We also showed that low-nitrogen conditions down-regulated the expressions of master genes, ZmNLPs, which were negatively correlated with the expressions of the nitrate transporters ZmNRTs. This indicates the existence of regulators that antagonize the function of ZmNLPs. Some genes related to N assimilation and carbon metabolism were also more expressed in MBST. This research shows that the low-nitrogen-tolerant line, MBST, transported nitrate and ammonium more effectively than the B73 line. The NUE was also higher in MBST than in B73.

En el ciclo agrícola primavera-verano de 2016 se evaluaron los híbridos P4082W, H565 y DK357 con fertilización química y química + biológica mediante un experimento factorial en arreglo de parcelas divididas. En los tratamientos con biofertilizante se inoculó la semilla con Glomus intraradices + Azospirillum brasilense; en la fertilización química se aplicó 120N-80P-80K. Se midieron las variables: altura, diámetro del cuello y número de hojas de la planta, número y peso de mazorcas con y sin brácteas, peso de brácteas, longitud y diámetro de la mazorca, número de hileras mazorca-1, peso de grano de 5 mazorcas, longitud, diámetro y peso del olote, rendimientos de grano, de forraje zacateado y de molido seco; para determinar la rentabilidad de los sistemas se calcularon el costo total (CT), ingreso total (IT), ingreso neto (IN) y la ganancia por peso invertido (GPI). El análisis estadístico incluyó análisis de varianza y prueba de comparaciones de medías con el método de Tukey. Se encontró que el híbrido DK357 registró la mayor altura, número de hojas, peso de grano, longitud de mazorca y del olote, rendimiento de grano y forraje tanto zacateado como molido seco. El genotipo P4082W obtuvo el mayor peso de mazorca con y sin brácteas. La fertilización química favoreció el rendimiento de forraje zacateado, y en combinación con la biológica, incrementó el rendimiento de grano. Los híbridos DK357 y P4082W cultivados con fertilización química y biológica resultaron rentables en los sistemas para producción de grano solo, forraje zacateado y grano y forraje seco molido.

Drought stress is a major limiting factor for the development of maize, and the identification of the expression of genes related to this stress in seeds and seedlings can be an important tool to accelerate the selection process. The expression of genes related to tolerance to water deficit in seeds and in different tissues of maize seedlings were evaluated. Four tolerant genotypes (91-T, 32-T, 91x75-T, 32x75-T) and four non-tolerant genotypes (37-NT, 57-NT, 37x57-NT and 31x37-NT) were seeded in a substrate with 10% (stress) and 70% (control) water retention capacity. The expression of 4 enzymes were evaluated: catalase (CAT), peroxidase (PO), esterase (EST), and heat-resistant protein (HRP), as well as the relative expression of 6 genes: ZmLEA3, ZmPP2C, ZmCPK11, ZmDREB2A/2.1s, ZmDBP3 and ZmAN13 were evaluated in seed, shoots and roots of seedlings submitted or not to stress. There was variation in the expression of CAT, PO, SOD, EST and HRP enzymes among the evaluated genotypes and also in the different tissues evaluated. Higher expression of the CAT and PO was observed in the shoots. There was a greater expression of the EST in the genotypes non-tolerant to water deficit. HRP was expressed only in seeds. In the aerial part of maize seedlings, classified as tolerant, higher expression of genes ZmLEA3 and ZmCPK11 was observed. There was a higher expression of the ZmAN13 and ZmDREB2A/2.1S genes in roots developed under stress conditions and a higher expression of the ZmPP2C gene in seeds of line 91-T, which is classified as tolerant to drought stress.

Assessment of energy efficiency (EE) enables the evaluation of the sustainability of agrosystems, as well as decision-making regarding reduction in production costs and environmental pollution and even to increase production in a sustainable way. In this context, the objective of this study was to assess energy efficiency in maize in different regions of Brazil. For this purpose, 32 areas of maize crop distributed across the major producing states and regions were assessed. Energy inputs and outputs of agricultural operations and/or agricultural inputs were calculated by multiplying the amount used by their calorific value or energy coefficient at each stage of production. Energy efficiency was calculated as the ratio between the total output energy and the total input energy during the production process. For every megajoule (MJ) of energy consumed in the production of second-crop maize and first-crop maize seasons, 9.9 and 8.7 MJ respectively of renewable energy were produced in the form of grain. In both maize cropping seasons, most of the energy use was attributed to fertilizers, herbicides and fuel. To be representative the evaluation of energy efficiency of the maize crop should be performed in different Brazilian cultivation regions, as it will represent different edaphoclimatic and management conditions spread over the national territory within an agricultural year.

O objetivo deste estudo foi avaliar o efeito da combinação de estratégias de adubação nitrogenada e de alturas de manejo da pastagem sobre a produção animal e de grãos em um Sistema Integrado de Produção Agropecuária. O experimento foi conduzido no município de Abelardo Luz-SC, entre abril de 2017 a abril de 2018. O delineamento experimental utilizado foi blocos ao acaso e os tratamentos dispostos em arranjo fatorial 2x2 com três repetições. O primeiro fator foi a altura do pasto manejado com lotação contínua: alta altura (AA) (20 cm) e baixa altura (BA) (12 cm). O segundo fator foram as épocas de aplicação do nitrogênio: na pastagem de inverno (NP), e na cultura de grãos, no verão (NG), em dose única de 200 kg N ha-1 em cobertura. A espécie forrageira utilizada durante a fase pastagem foi a aveia preta (Avena strigosa Schreb) e o pastejo foi realizado por novilhos cruza Nelore x Charolês com peso corporal inicial de 260 kg. A cultura de verão foi o milho (Zea mays). O ganho médio diário (GMD) e a oferta de forragem foram maiores em AA comparativamente à BA, enquanto a carga animal foi maior em BA. Para as épocas de aplicação do N, a carga animal foi maior em NP. As variáveis número de fileiras por espiga, número de grãos por fileira e peso de mil grãos não foram afetadas pelo manejo da altura do pasto e nem pela estratégia de adubação nitrogenada, bem como a produção total de grãos, que apresentou média geral de 14.090 kg ha-1. Concluiu-se que a inversão da adubação nitrogenada entre os períodos de produção de pasto de inverno e de cultivo de grãos, e a altura de manejo da pastagem de aveia preta não comprometem a produção de grãos de milho no verão e nem a produção animal por área. Entretanto, o desempenho dos novilhos é maior (maior GMD) quando o pasto é manejado a 20 cm, enquanto a alta intensidade de pastejo reduz significativamente a palhada sobre o solo.

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Currently, the main maize production areas in northeastern China are facing soil fertility loss, which severely affects root growth and limits photosynthesis. It is widely acknowledged that physiological conditions of the root system are closely related to the photosynthetic capacity; therefore, we evaluated whether there are certain differences in root bleeding sap characteristics and photosynthetic capacity between the hybrids and their parents. The results showed that heterosis of the photosynthetic capacity occurred at the milk-ripe stage; however, heterosis of bleeding-sap mass (BSM) and organic biomass occurred during the whole growth period. Photosynthetic rate correlated positively with BSM and the bleeding components; a similar trend was also observed between BSM and bleeding components. These data suggested that appropriate water and fertilizer supply can improve the photosynthesis-related parameters and yield of maize.

Currently, mixed systems for growing annual crops with forage plants of the Brachiaria genus represent an excellent alternative for the cultivation of maize by using the area for agricultural and livestock farming, which provides higher income to the grower and sustainability to the agricultural systems of the Cerrado. However, little is known about the best means for sowing such intercropped plants. Thus, the objective of this study was to evaluate the agronomic characteristics of maize (Zea mays) as well as the productive and nutritional characteristics of Paiaguas palisadegrass (Brachiaria brizantha cv. BRS Paiaguas) as the second crop in integrated production systems. The experimental design used randomized blocks with four replications. The treatments consisted of the following forage systems: monocropped of maize, monocropped of Paiaguas palisadegrass, maize intercropped with Paiaguas palisadegrass in rows, maize intercropped with Paiaguas palisadegrass between rows, and maize with oversown Paiaguas palisadegrass. The results showed that intercropping of maize with Paiaguas palisadegrass does not interfere with the agronomic characteristics or grain yield of maize, regardless of the system that was adopted. Regarding the production of forage, low production of dry matter was found for Paiaguas palisadegrass oversown in maize, though the nutritional value was better. Intercropping maze and Paiaguas palisadegrass is relevant to integrated production systems, as it allows for of a third harvest in the same crop year, which maintains sustainability especially because a smaller arable area is used compared to conventional systems.

A utilização de resíduos animais provenientes da avicultura como fertilizante orgânico é uma maneira sustentável de utilização dos resíduos desse sistema de produção, porém ainda há poucos estudos sobre a dinâmica de disponibilização dos nutrientes. O objetivo deste trabalho foi avaliar o uso de cama de aves associada à fertilizante nitrogenado na cultura do milho e a disponibilização de nitrogênio da cama de aves durante três anos de cultivo. Foi utilizado o delineamento em blocos casualizados, no esquema fatorial 3x5+1. Os fatores consistiram doses de cama de aves (2, 5 e 8 Mg ha-1) e doses de nitrogênio (0, 50, 100, 150, 200 kg ha-1). A testemunha recebeu fertilizante mineral na semeadura na dose de 120, 80 e 20 kg ha-1 de P205, K2O e N, respectivamente e em cobertura com 200 kg ha-1 de N. Foram feitas leituras com clorofilômetro, altura de plantas, altura de espigas, produtividade, massa de cem grãos e número de grãos por espiga. As maiores doses de cama de aves utilizadas em três anos sucessivos, mesmo sem N em cobertura, propicia produtividade semelhante à testemunha com fertilizante mineral na cultura do milho. A cama de aves é alternativa viável na adubação da cultura do milho.

Effects of lanthanum chloride (LaCl3) on chromium tolerance of maize were investigated at chloroplast level. The results showed that Cr stress significantly increased activities of ascorbate peroxidase, glutathione reductase, monodehydro-ascorbate reductase, dehydroascorbate reductase, superoxide dismutase, and glutathione peroxidase, nonphotochemical quenching, malondialdehyde (MDA) and hydrogen peroxide contents, but significantly reduced the ratios of reduced ascorbate to dehydroascorbate and reduced glutathione to oxidized glutathione, the contents of chlorophyll and carotenoids, maximum photochemical efficiency of PSII, photochemical quenching, quantum efficiency of PSII photochemistry, net photosynthetic rate, plant height and biomass, compared with control. Compared to Cr stress alone, LaCl3 significantly reduced MDA and H2O2 contents and increased other indicators under Cr stress. LaCl3 alone also enhanced above indicators except MDA and H2O2, compared with control. Our results suggested that LaCl3 improved the Cr tolerance of maize crops by upregulating the antioxidant capacity and the function of chloroplasts.

The aim of this study was to evaluate the composition, voluntary intake, and digestibility of the diet of Holstein cows, as well as milk yield and milk composition as a function of different roughage sources used under experimental feeding conditions in Brazil, through meta-analysis. The database of this study consisted of 109 experiments with 424 treatments of 3,903 lactating Holstein cows. The data were obtained from studies published between January 2000 and December 2015, and were evaluated by variance analysis. Lactating dairy cow diets with a single source of roughage other than corn silage resulted in lower voluntary intake, milk yield, and differences in milk composition, compared to diets based on corn silage or the combination of two roughages, probably due to reduced nutrient digestibility. Diets based on corn silage are distinguished by feed efficiency, milk yield, and composition. Diets based on the combination of two roughage sources are similar with respect to milk yield and composition, compared to diets based on corn silage; whereas, diets with a single source of roughage (other than corn silage), even when containing a higher proportion of concentrate, led to reduced voluntary intake, milk yield, and food efficiency due to the lower utilization of the nutrients. Diets based on corn silage in general allow a higher proportion of roughage in the diet due to energy density.

Food intake is determinant in the production process and can be modified when more than one type of forage is supplied in the diet. The aim of this study was to evaluate the effects of supplementation with corn silage + soybean meal (9:1 based on DM) in the proportion of 10 g DM kg?1 live weight (LW) for lambs receiving pre-dried ryegrass (Lolium multiflorum Lam) in two forage supply levels: ad libitum or restricted (60% of the consumption ad libitum). Eight castrated male sheep crosses Texel × Criollo (average of 31.5 ± 2.2 kg LW) were used in an experimental design of 4 × 4 Latin square. Each experimental period was performed for 19 days, with 14 days for adaptation and 5 days for collections. Animals were fed three times a day (08h00, 11h30, and 16h30). Supplemented animals received corn silage at 08h00 and ryegrass silage at 11h30 and 16h30. The substitution rates (kg DM consumed forage per kg DM consumed silage) were 0.93 for animals with a supply of ryegrass ad libitum and zero for those receiving the same in a restricted amount. The digestible OM (DOM) intake and nitrogen retention did not vary with supplementation in animals that received ryegrass ad libitum but increased in those with restricted supply. However, animals with restricted supply and supplemented had a less digestible OM intake and nitrogen retention than the average of those that received ryegrass ad libitum. Organic matter digestibility and efficiency of microbial protein synthesis were not affected by treatments, but the digestibility of NDF and ADF was lower in supplemented animals when compared to those non-supplemented and in restricted supply when compared to consumption ad libitum. Even with supplementation, feed restriction of base forage can limit the daily intake of digestible OM and the daily retention of N in sheep.

A reduzida longevidade e o baixo desempenho de sementes de milho doce justificam a adoção de práticas que potencializem sua qualidade, como a pré-embebição. Neste sentido, objetivou-se avaliar os efeitos da pré-embebição com giberelina no potencial fisiológico de dois lotes de sementes de milho doce, com níveis de vigor contrastantes, em condições ideais e de estresse hídrico. Inicialmente, os lotes de sementes utilizados foram caracterizados quanto a germinação e potencial fisiológico - através dos testes: primeira contagem, germinação envelhecimento acelerado, teste de frio, comprimento de plântulas normais, massa seca de plântulas normais, emergência em campo, índice de velocidade de emergência e teste de tetrazólio. Posteriormente, as sementes foram submetidas a diferentes tratamentos de pré-embebição, em delineamento inteiramente casualizado, em esquema fatorial 2 × 4, com quatro repetições, sendo dois lotes e quatro tratamentos de pré-embebição: com água e com solução de ácido giberélico à 0,4 g L-1 e à 0,8 g L-1, além do controle (sem pré-embebição). Em seguida, as sementes foram submetidas aos testes de primeira contagem e germinação em condições de deficiência hídrica simulada, além dos testes de grau de umidade, primeira contagem, germinação, emergência em campo e índice de velocidade de emergência. Os dados obtidos foram submetidos a análise de variância e comparação de médias, pelo teste de Tukey e pelo teste t de Student, para comparação entre os tratamentos e os lotes, respectivamente. A pré-embebição favoreceu a velocidade e porcentagem de germinação das sementes de milho doce, principalmente em condições de déficit hídrico. A pré-embebição somente com água, no lote de maior vigor, e com ácido giberélico à 0,4 g L-1, no lote de menor vigor, favorece o desempenho fisiológico das sementes avaliadas.

Cationic micronutrients bioavailability depends on the chemical characteristics of soil fractions. Fourteen soils received individual doses of five micronutrients (Cu, Fe, Mn, Zn, B) arranged in seven treatments set according a Baconian Matrix. The soils incubated with treatments during 15 days had corn cultivated in greenhouse for 30 days, in three consecutive growth cycles. The cationic micronutrients were determined in the corn shoots after each growth cycle. Soil samples collected before the first and after each growth cycle had the available concentrations of Cu, Fe, Mn and Zn determined by single extractions (Mehlich-1 and DTPA-pH 7.3) and by sequential extraction. Correlation analysis was performed for the Cu, Fe, Mn and Zn concentrations determined in the corn shoots, the available concentrations of Cu, Fe, Mn and Zn in the soils (Mehlich-1 and DTPA) and the concentrations of Cu, Fe, Mn and Zn in the soil fractions (sequential extraction). The distribution of available metals forms in fractions reflected their affinity with soil components. Soil available Cu correlated with Cu bound to organic matter. The exchangeable fraction was the main source of soil available Mn and Zn. The Fe availability related mainly to the Mn oxides, Fe oxides, and exchangeable fractions. The plants absorbed Cu mainly from the Mn-oxides and organic matter fractions. Manganese absorbed by plants originated from the exchangeable and Mn-oxides fractions. The Zn absorbed by plants originated mainly from the exchangeable fraction. Correlations of single metal extractions (Mehlich-1 and DTPA) with Cu, Mn and Zn contents in plants were positive.

Sowing date and nitrogen (N) fertilisation modify the morpho-physiological characteristics of maize (Zea mays L.) plants, which can alter the yield. The aim of this study was to analyse the effects of sowing date and N rate on the growth-pattern characteristics of maize hybrids with contrasting cycles, and the subsequent relationship with grain yield. Two experiments were set up in Santa Catarina State, southern Brazil. Two maize hybrids (AG9025, super-early cycle; P30F53, early cycle), two sowing periods (early spring and late spring), and four rates of topdressed N (0, 150, 300 and 450 kg N ha−1) were tested. Plant height, leaf area index (LAI), and relative chlorophyll content (RCC) were evaluated. The increment in N rate increased plant height at the silking stage for early spring sowing, and had no effect for late spring sowing. Higher N rates increased plant height of P30F53 and did not affect plant height of AG9025. Increasing the N rate enhanced LAI and RCC at silking more sharply when maize was sown in early spring. Higher N rates resulted in increased RCC during grain-filling, as well as maintenance of LAI, factors that were strongly associated with grain yield, especially for early spring sowing with hybrid P30F53. This research shows that the use of increasing N rates is an adequate management strategy to increase maize grain yield when the crop is sown in early spring. When applied at this sowing time, N has greater effect on the elevation of LAI and RCC and their maintenance during grain filling. Sowing date affects the environmental conditions experienced during maize development, which modifies maize response to nitrogen (N) fertilisation, depending on the hybrid cycle. The use of increasing rates of topdressed N enhances maize capacity to intercept solar radiation and to convert it into grain production. The use of high rates of N is an adequate management strategy to increase the yield when the crop is sown at the beginning of spring. [ABSTRACT FROM AUTHOR]

In the International Space Station experiment 'Auxin Transport', polar auxin transport (PAT) in shoots of etiolated maize (Zea mays L. cv. Golden Cross Bantam) grown under microgravity in space was substantially enhanced compared with those grown on Earth. To clarify the mechanism, the effects of microgravity on expression of ZmPIN1a encoding essential auxin efflux carrier and cellular localisation of its products were investigated. The amounts of ZmPIN1a mRNA in the coleoptiles and the mesocotyls in space-grown seedlings were almost the same as those in 1 g -grown seedlings, but its products were not. Immunohistochemical analysis with anti-ZmPIN1a antibody revealed a majority of ZmPIN1a localised in the basal side of plasma membranes of endodermal cells in the coleoptiles and the mesocotyls, and in the basal and lateral sides of plasma membranes in coleoptile parenchymatous cells, in which it directed towards the radial direction, but not towards the vascular bundle direction. Microgravity dramatically altered ZmPIN1a localisation in plasma membranes in coleoptile parenchymatous cells, shifting mainly towards the vascular bundle direction. These results suggest that mechanism of microgravity-enhanced PAT in maize shoots is more likely to be due to the enhanced ZmPIN1a accumulation and the altered ZmPIN1a localisation in parenchymatous cells of the coleoptiles. In the 'Auxin Transport', space experiment, polar auxin transport in shoots of etiolated Golden Cross Bantam maize grown in space was greater than those grown on Earth. Microgravity substantially altered ZmPIN1a localization in plasma membranes of the parenchymatous cells of the coleoptiles, shifting mainly towards the vascular bundle direction. These findings contribute to the field of gravitational physiology in plants, and also to development of plant cultivation system in space for long-term exploration of space by human being in future. [ABSTRACT FROM AUTHOR]

The use of silage has been an efficient alternative to feed supply during the shortage of roughage in dry periods, providing quality feed that is widely used in ruminant feeding. Thus, the objective of this study was to evaluate the fermentative characteristics and nutritive value of corn silage with Tamani guinea grass (Panicum maximum BRS cv. Tamani) through chemical composition, in vitro dry matter digestibility and protein fractionation. The experiment was conducted in a completely randomized design with four replications. The treatments consisted of five silages: corn; corn with 10% Tamani guinea grass; corn with 20% Tamani guinea grass; corn with 30% Tamani guinea grass; and corn with 40% Tamani guinea grass, totalling 20 experimental silos. The addition of tamani grass to silages was determined based on fresh matter. For ensiling, corn was harvested with 320 g kg-1 DM (dry matter) and Tamani guinea grass in a 30-day development cycle with 286 g kg-1 DM. After 50 days of silage, the silos were opened to analyse the fermentative characteristics, chemical composition and protein fractionation of the silage. The results showed that the addition of Tamani guinea grass in corn silage increased the pH and buffering capacity and reduced the dry matter and lactic acid concentration but did not compromise the fermentative characteristics of silages. The addition of 40% Tamani guinea grass in corn silage provided increased levels of crude protein, in vitro dry matter digestibility, protein A, B1 and C, and decreased the fractions B3 and C, which makes Tamani guinea grass an alternative to improve the quality of exclusive corn silage, resulting in better quality silage.

Maize represents one of the most cultivated crops of cereals in the world, being used as a source of grain, silage and biofuel. Nitrogen is very required in the maize crop, making nitrogen fertilization a significant part of the production cost. The objective of this study was to evaluate the response of two sources of N, urea and coated urea of controlled release, regarding the productivity and the cost/benefit ratio in maize for 2nd harvest. The experiment was carried out in the field in soil classified as dystroferric Red Latosol and treatments distributed in experimental plots, following the randomized block design with four replications. The treatments were 40 kg N ha-1 of common urea; 60 kg N ha-1 of common urea; 40 kg N ha-1 of coated urea; 60 kg of N-coated urea and the control without application of N broadcast application in planting. The maize crop responded to the application of nitrogen at planting. However, the use of coated urea did not increase the grain yield in relation to the use of common urea. The economic analysis demonstrated a better efficiency of use of N and the best net revenues with the application of the dose of 40 kg N ha -1 of common urea in the planting of the crop.

Precision agriculture is a set of techniques that assist the monitoring of the agronomic performance of the maize crop by using vegetation indices. This study aimed to verify the relationship between vegetation indices, plant height, leaf N content, and grain yield of three maize varieties, grown under high and low N as topdressing. The experiment was carried out at the Fundação de Apoio à Pesquisa Agropecuária de Chapadão (Fundação Chapadão), located in the municipality of Chapadão do Sul, during the 2017/2018 season. The experiment consisted of a randomized block design with four replications, arranged in a 3x2 split-plot scheme. The first factor (plots) corresponded to three open-pollinated maize varieties (BRS 4103, BRS Gorotuba, and SCS 154), and the second factor (subplots) consisted of two N rates applied as topdressing (80 and 160 kg- 1). All the evaluated variables showed varieties x N interaction. Vegetation indices in maize varieties were influenced by the N rate applied as topdressing. Normalized Difference Vegetation Index (NDVI) and Soil-adjusted Vegetation Index (SAVI) showed a higher correlation with plant height. At the same time, Normalized Difference Red Edge (NDRE) had a stronger association with leaf N content.

A adequação do arranjo espacial do milho é uma ferramenta capaz de promover melhor aproveitamento do ambiente agrícola, permitindo à cultura expressar seu potencial produtivo. Objetivou-se avaliar o desempenho agronômico do híbrido de milho AG 7098 VT PRO 2, no município de Rio Verde - GO, cultivado em distintos arranjos espaciais de plantas e épocas de semeadura. O trabalho foi conduzido em delineamento de blocos casualizados, com cinco repetições, em esquema fatorial 2 x 4, em que se utilizou dois espaçamentos entrelinhas (0,25 m e 0,5 m) e quatro populações de plantas (45, 60, 75 e 90 mil plantas ha-1), em duas épocas de cultivo (26 de janeiro e 15 de fevereiro de 2017). Avaliou-se características morfológicas, componentes do rendimento e a produtividade de grãos, posto que os dados de cada época de semeadura foram analisados, separadamente. Na primeira época, o aumento da população em até 85 mil plantas ha-1 resultou em acréscimo da produtividade de grãos, uma vez que não houve efeito da redução do espaçamento entrelinhas para as características avaliadas. O milho semeado na segunda época, em espaçamento entrelinhas de 0,25 m, proporcionou aumento da produtividade de grãos, demonstrando que o adensamento de plantas pode ser alternativa promissora em épocas, nas quais as condições climáticas são menos favoráveis ao desenvolvimento da cultura na região do Cerrado.

A produtividade de milho no Brasil vem aumentando gradativamente, e o armazenamento adequado da produção é uma questão de segurança, sendo assim, quando conduzido adequadamente, a qualidade do produto é preservada e as perdas são evitadas ou minimizadas. Assim, o monitoramento, o controle da temperatura e umidade se torna fundamental. Objetivou-se verificar a qualidade da leitura dos equipamentos utilizados para a determinação do teor de água em grãos de milho em função das épocas de semeadura, e também verificar a correlação existente entre os equipamentos. O experimento foi conduzido na Fazenda de Ensino Pesquisa e Extensão (FEPE), pertencente a UNESP/FCAV em Jaboticabal-SP. O delineamento experimental foi baseado nas premissas básicas do Controle Estatístico de Qualidade - CEQ. Foram avaliadas três áreas experimentais com dois híbridos de milho e com diferentes dias após a semeadura, sendo: área A (híbrido AS1633PRO2 aos 132 DAS), área B (híbrido AS1555RR2 aos 125 DAS) e área C (híbrido AS1633PRO2 aos 150 DAS). A fim de avaliar o teor de água dos grãos, foi empregado o método expedito, por meio de sensores de umidade e o método da estufa. Para o método expedito utilizou-se dois sensores que constam de princípio de medição dielétrica (umidade por capacitância). A maior qualidade de leitura foi no Equipamento 1, e a área C apresentou menor variabilidade, devido aos adequados pontos de maturação fisiológico para a colheita como também ao do teor de água do grão, e também demonstrou média superior de produtividade. Os equipamentos 3 e 1 tiveram melhor correlação nas avaliações, devido a calibração do equipamento 1 ter apresentado leituras próximas ao do método padrão (Equipamento 3).

The objective of this study was to conduct a meta-analysis of scientific publications from January 1994 to December 2014, to evaluate the chemical composition of corn plants, green forage, and silages of three different types of maize hybrids (simple, double, and triple) used in experimental conditions in Brazil. The sub-bases Corn Cultivation and Green Fodder were composed of 49 experiments, consisting of 481 treatments, and the sub-base Silage consisted of 24 studies composed of 163 treatments, involving 478 silos. In the Corn Cultivation sub-base, the variables of spacing, plant height, grain yield, organic matter content, and total carbohydrates of maize silage differed (P < 0.05) according to the hybrid type. The number of corn plants per hectare, number of spikes per plant, and the levels of neutral detergent fiber, acid detergent fiber, hemicellulose, and lignin did not differ (P > 0.05) according to the hybrid type. In the Green Forage sub-base (ensilage), the main difference (P < 0.05) was regarding the in vitro dry matter digestibility, whereby the triple hybrids (59.38%) had lower values than the simple (73.05%) and double (72.74%) hybrids. In the Silage sub-base, the variables of organic matter, total carbohydrates, cellulose, in vitro dry matter digestibility, and pH differed (P < 0.05) according to the hybrid type. While the variables dry matter, non-fibrous carbohydrates, neutral detergent fiber, acid detergent fiber, hemicellulose, lignin, total digestible nutrients, ethereal extract, crude protein, and ammonium nitrogen did not differ (P > 0.05) according to the hybrid type. The variability in the determination of parameters, such as dry matter yield, dry matter content, and non-fibrous carbohydrates of corn silage, and the non-determination of the starch content demonstrated that the chemical compositions of Brazilian corn silage have not yet been fully clarified. The types of maize hybrids (simple, double, and/or triple) mainly differ in terms of grain production. In many situations, the silage processes are not conducted in an ideal way, and the differences as a function of the maize plants (type of hybrid) are minimized due to losses during the ensiling process.

Salinity is a devastating problem of arid and semi-arid climatic regions with uneven salt accumulation which hinders growth and development of crops. The deleterious effects of salinity mainly depend on level and source of salinity. We hypothesized that types of sodium salt (NaCl and Na2SO4) might cause variable toxicity in maize (Zea mays L.) plants. The objective of the present study was to compare the effect of different types of sodium salt (NaCl and Na2SO4), each at EC 5 and 10 dS m–1 on growth, physiology and nutrient contents of maize plant grown in earthen pots under wire house conditions. Results revealed toxic effects of salt stress on seed germination, root and shoot growth and biomass. Maize physiology in terms of sub-stomatal CO2 index, chlorophyll and relative water contents, photosynthetic and transpiration rate also reduced under salt stress. Among the types of salt and levels of salinity, NaCl applied at the rate of 10 dS m–1 caused the highest reduction in seed germination, growth and physiology due to high accumulation of Na and Cl ions whereas low in K ion in maize plant tissues. Based on the findings, we do conclude that NaCl applied at the rate of 10 dS m–1 has more negative impact on maize growth and nutrient acquisition than Na2SO4 at same level of salinity.

Neste trabalho foi confeccionado o modelo didático do corte transversal da folha de Zea mays. O qual possui grande importância na formação, levando em conta que este pode ser utilizado em aulas práticas em sala de aula, uma vez em que no modelo didático os alunos poderão visualizar e manusear o objeto de estudo, facilitando na compreensão de conteúdos de anatomia, inclusive para pessoas com deficiência visual, pois o modelo é tridimensional, contendo assim diferentes texturas. O uso destas ferramentas de ensino permite que o professor realize suas aulas de forma prática, simples e menos complexa do ponto de vista dos alunos. A visualização de uma estrutura em três dimensões pode facilitar o processo de ensino e aprendizagem nos diferentes níveis de ensino, já que as escolas da rede pública em sua grande maioria não dispõem de microscópio e outros equipamentos que viabilizem a visualização de estruturas microscópicas e facilitem o estudo de ciências. Para a referida construção, tomou- se como base as estruturas visíveis no corte transversal da folha de Zea mays. Buscou-se fidelidade ao que é visto em lâminas das aulas práticas, se teve o cuidado de colocar as estruturas de acordo com suas posições e cores vistas.

Resistance of maize inbred lines to major leaf diseases should be characterized for the development of new hybrids in breeding programs. Thus, this study aimed to assess the severity of leaf diseases in maize inbredlines with different kernel hardnessand two sowingseasons. We assessed four inbred lines and one check hybrid with dent kernels and four inbred lines and a check hybrid with flint kernels. Treatments were conducted in two sowing seasons, one in October, and another in December 2013. The symptoms of gray leaf spot (Cercospora zeae-maydis), northern leaf blight (Exserohilum turcicum), and white leaf spot (a complex of Phaeosphaeria maydis and Pantoea ananatis) were assessed every 10 days from flowering. The area under the disease progress curve was also calculated. Severity level of the diseases was higher in inbred lines when compared to the check hybrds (AG8041 PRO and P30R50YH), regardless of kernel hardness. Dent-kernel inbred lines showed a higher severity of northern leaf blight symptoms when compared to flint-kernelones. It is worth mentioning that disease severity increased as sowing was delayed.

Galactolipids (MGDG and DGDG) and sulfolipids (SQDG) are key components of plastidic membranes, and play important roles in plant development and photosynthesis. In this study, the whole families of MGD , DGD and SQD were identified in maize genome, and were designated as ZmMGD1 - 3 , ZmDGD1 - 5 and ZmSQD1 -5 respectively. Based on the phylogenetic analyses, maize and Arabidopsis MGDs, DGDs and SQDs were clearly divided into two major categories (Type A and Type B) along with their orthologous genes from other plant species. Under low-phosphorus condition, the expression of Type B MGD , DGD and SQD genes of maize and Arabidopsis were significantly elevated in both leaf and root tissues. The lipid analysis was also conducted, and an overall increase in non-phosphorus lipids (MGDG, DGDG and SQDG), and a decrease in phosphorus lipids (PC, PE and PA) were observed in maize leaves and roots under phosphate deficiency. Several maize MGD and SQD genes were found involved in various abiotic stress responses. These findings will help for better understanding the specific functions of MGDs, DGDs and SQDs in 18:3 plants and for the generation of improved crops adapted to phosphate starvation and other abiotic stresses. The synthesis and metabolism of lipids in photosynthesis membrane plays important roles in plant development and stress adaptation. In this study, for the first time, the genes involved in plastidic lipids metabolism were identified from maize and their differential roles in responses to low-phosphate and environmental stresses were revealed. The findings will be conducive to generate improved crops adapted to phosphate starvation and other abiotic stresses. [ABSTRACT FROM AUTHOR]

Corn and grass intercropping is an interesting practice, and forage plants belonging to the genus Urochloa are the most commonly used in these situations. These plants show excellent adaptation to low-fertility soil, easy establishment, considerable biomass production, as well as being an important competitor with weeds. In agrosilvopastoral systems, the yield of corn crops grown together with trees is hindered due to the reduced radiation incidence caused by tree shading. This study aimed to evaluate corn growth, light interception, and chlorophyll content when intercropped with marandu grass in an agrosilvopastoral system with one and three eucalyptus rows, and compare them with plants under full sun. The experiment was conducted in Andradina - SP (Brazil). Treatments consisted of intercropping with no eucalyptus (plants under full sun: control), one system with one eucalyptus row and another with three rows. We also assessed the effect of five distances between corn plants and eucalyptus trees (2, 4, 6, 8, and 10 m). Between eucalyptus rows, corn plants were intercropped with marandu grass. The analyzed variables were corn plant height, ear height, chlorophyll content index, light interception, dry matter, and fresh and dry forage weights. The experimental design was a randomized block in a factorial scheme plus a control, with four repetitions. Tree arrangements had no influence on corn forage, dry matter, plant height, or ear height. Lower results of yield, dry matter, plant height, and ear height were observed for plants spaced 2 m from trees. In the first two evaluations, significant differences of light interception were found for the different distances. Neither tree arrangements (one and three rows) nor the distances from the trees had any impact on corn heights, with no difference between control and the agrosilvopastoral systems. Neither plant distances from trees nor tree arrangements had an influence on chlorophyll content index of corn plants, with no difference between control and the treatments. As a result, corn growth and forage yield under agroforestry systems are similar in arrangements of 1 and 3 eucalyptus rows (15-month-old trees) and under full sun. However, corn dry matter contents were lower in systems containing trees. Intercropping corn and marandu grass in a system without trees increased light interception at harvest time, indicating a larger soil coverage. Corn forage yield and dry matter content were lower when plants were 2 m apart from eucalyptus trees since this condition provided a lower amount of light and greater competition for water and nutrients.