Acta Scientiarum. Agronomy

Modeling and simulation of liquid fertilizer devices for nitrogen top dressing in maize fields

Marcelo José da Silva — 2026-02-27

Nitrogen top dressing is essential to supplement maize needs in crop fields. In Brazilian agriculture, a spreader is the most popular equipment used to apply nitrogen fertilizer to growing maize. However, spreaders present at least three problems: non-uniform fertilizer placement, granular fertilizer placement on the top of maize leaves, and granular fertilizer scattering without a precise target. As an alternative, liquid nitrogen fertilizer applied in side bands of maize rows can improve nutrient placement and dosage precision. The objective was to design a liquid fertilizer application device for assembly on a boom sprayer. For this, a programming model was simulated in Matlab. The liquid fertilizer source, fertilizer rate, maize row width, and boom sprayer speed were considered as input parameters. The simulation assisted in the design of the liquid fertilizer device. The device was constructed and evaluated on a laboratory bench. As a result, pressure, nozzle outlet flow, and forward speed were compatible with a self-propelled sprayer. The proposed process showed the potential to improve the outlet flow quality (coefficient of variation less than 10%). In addition, the liquid fertilizer device was considered simple to assemble in the sprayer’s boom. These characteristics could represent some attractive aspects for the farmers.

Hygroscopicity and thermodynamic properties of grains of Moringa oleifera L.

Jose Renato Robles Padilla — 2025-10-21

The Moringa plant, widely recognized for its uses in both animal and human nutrition as well as in medicine, has seeds rich in oil and protein. For their maintenance and processing, safe storage conditions are needed, in addition to an understanding of the energy required for this process. The objective of this work was to study the hygroscopic and thermodynamic properties of moringa grains. The static gravimetric method was used at temperatures of 20–70°C and relative humidities of 10.75–85.11%. Nine mathematical models were fitted to the experimental water sorption data. The modified Halsey model provided the best fit, with an R² of 97.72%, P of 6.71%, and SE of 0.01, and was therefore used to calculate the thermodynamic properties. An increase in the equilibrium water content from 0.039 to 0.162 (db) resulted in a decrease in the energy released during adsorption (Q_st) from -3613.589 to -2453.029 kJ kg^-1, the differential entropy (∆S) from -2.519 to -0.115, and Gibbs free energy (∆G) from -351.897 to -21.773. This process was considered spontaneous.

A comparative study of automatic guidance signals and planting speeds for corn

Jarlyson Brunno Costa Souza — 2025-10-21

Planting is considered one of the most critical mechanized agricultural operations, because any errors during this stage could cause significant yield losses. In this context, the use of automatic guidance systems can minimize errors in the row parallelism and alignment, ensuring consistent spacing and optimal operational speeds. Therefore, the objective of this study was to evaluate the effects of different GNSS correction signals and forward speeds on the corn planting. The treatments consisted in two GNSS correction signals for automatic guidance: SF1 – a free-to-use signal with ±23 cm pass-to-pass parallelism error, and SF2 – a subscription-based signal with ±5 cm pass-to-pass parallelism error; and three forward speeds (5, 6, and 8 km h^-1). The depth and longitudinal seed distribution (classified as double, skipped, and acceptable spacings) were evaluated using statistical process control (SPC) and descriptive statistical methods. The results showed that the SF2 signal provided superior seeding quality, characterized by lower variability and enhanced process stability. Therefore, usage of the subscription-based SF2 signal is recommended to achieve optimal seeding quality. It improves the seed distribution and link to acceptable parallelism correction.

A simple approach for obtaining unsaturated hydraulic conductivity based on the soil water content

Marcos de Sousa Campos — 2026-02-26

Knowledge of soil hydraulic conductivity is indispensable due to its application in studies of soil water dynamics, water balance, and irrigation management in crops that directly affect water and soil conservation. The objective of this study was to propose two alternatives for determining unsaturated hydraulic conductivity using existing methodologies in the literature based on the variation in soil moisture and water storage monitored using a moisture sensor in a drainage lysimeter and under field conditions. Two experiments were conducted, one in a drainage lysimeter and the other in the field at Embrapa Cassava and Fruit Farming, Cruz das Almas, Bahia State, Brazil. A comparison of moisture and storage variation between the proposed methodologies was carried out based on statistical coefficients. The methods based on moisture and storage variation in a layer estimated the unsaturated hydraulic conductivity with good accuracy compared to Hillel’s method. Hydraulic conductivity showed greater variation in the initial phase of water redistribution in the soil, either in the lysimeter test or in the field application after irrigation. The proposed methods based on moisture and storage variation can be applied to studies on soil water dynamics in the soil moisture profile using soil water sensors.

Parameterization of the apsim model for irrigated maize–signalgrass intercropping system

Jose Roberto de Oliveira — 2026-02-26

The Agricultural Production Systems Simulator (APSIM) has been widely used in studies to simulate the growth and development of pastures and grain crops in single-crop and intercropping cultivation systems. The objective of this study was to parameterize the APSIM and evaluate its effectiveness in estimating the growth and productivity of maize and signalgrass (Urochloa ruziziensis) in single-crop and intercropping systems in northern Piauí State, Brazil. Data were collected from the experimental field of the Brazilian Agricultural Research Corporation (Embrapa Mid-North) in Teresina, Piauí State, Brazil. The photosynthetically active radiation and soil water content were the main measurement parameters to calibrate the light extinction coefficient and radiation use efficiency, with adjustments to the phenological and structural parameters of maize. The leaf, stalk, and total shoot dry weights and leaf area index (LAI) of both crops and maize organs (husk, cob, and grains) were evaluated. The model showed coefficient of determination (R²) values ranging from 0.81 to 0.99 and Nash–Sutcliffe efficiency (NSE) values ranging from 0.72 to 0.99 for single-crop cultivation of signalgrass; R² values ranging from 0.87 to 0.93 and NSE values ranging from 0.62 to 0.67 for intercropping cultivation of signalgrass; R² values ranging from 0.43 to 0.97 and NSE values ranging from -3.33 to 0.95 for single-crop cultivation of maize; and R² values ranging from 0.30 to 0.93 and NSE values ranging from 0.21 to 0.92 for intercropping cultivation of maize. The APSIM model provided an adequate fit for growth simulations of signalgrass and maize in single-crop and intercropping systems. It can simulate the growth and yield of irrigated signalgrass and maize in single-crop and intercropping systems.

Essential oil of Citrus aurantium var. dulcis: A new approach to control Diatraea saccharalis and Spodoptera eridania larvae

Richard Henrique Siebra Bergamo — 2025-10-20

Studies focusing on the potential use of botanical insecticides have increased significantly in recent years. Essential oils extracted from citrus fruit peels contain limonene, a monoterpene that is widely used in agricultural pest control studies. This study aimed to investigate the insecticidal properties of the essential oil of Citrus aurantium (L.) var. dulcis and analyze its effects on the midgut of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) and Spodoptera eridania (Stoll, 1782) (Lepidoptera: Noctuidae) neonate larvae. After essential oil dilution, five concentrations (0.06; 0.12; 0.25; 0.50 and 1.00%) were obtained and topically applied to the prothorax of larvae. Behavioral observations and larval mortality data were recorded every 24h for a duration of 120h. Midgut samples were collected 24 and 48h after the bioassays to perform histological and ultrastructural analyses. Both species exhibited low mobility, which progressed to paralysis after treatment, and mortality was only recorded in the first 48h. D. saccharalis and S. eridania larvae treated with 1.00% essential oil concentration had mortalities of 89 and 47%, respectively. The lethal concentrations (LC₅₀) of essential oil have been estimated to be 0.50% (CI = 0.45–0.57%) for D. saccharalis and 1.06% (CI = 0.89–1.35%) for S. eridania. The histological and ultrastructural analyses revealed significant midgut damage, such as detachment of the muscle fibers from the basal region of the epithelium and spacing of columnar cells, which progressed to a complete degeneration of the epithelial cells. The negative effects of C. aurantium var. dulcis essential oil on D. saccharalis and S. eridania neonate larvae indicate its bioinsecticide potential. Our results suggest that this essential oil can be implemented in integrated pest management for sustainable crop production.

Fuzzy logic in the simultaneous selection of quantitative and qualitative descriptors for kale

Ana Clara Gonçalves Fernandes — 2025-10-20

Simultaneous selection in genetic improvement presents difficulties in selecting qualitative traits as well as the desired commercial ranges for quantitative traits. Thus, fuzzy logic has become an alternative, enabling the computational modelling of the researcher’s experience. This study aimed to assess the efficiency of fuzzy logic in simultaneous selection considering both qualitative and quantitative descriptors. The developed methodology was applied to data from two experiments with kale half-sibs. The first experiment was carried out in Viçosa in randomised blocks, with 24 families of kale half-sibs, 4 replications, and 5 plants per plot. The second experiment was carried out in Montes Claros in randomised blocks, with 36 kale genotypes, 33 families of half-sibs, and 3 commercial cultivars, with 4 replications and 6 plants per plot. Quantitative and qualitative traits were evaluated, and individual genetic values were obtained using REML/BLUP. Genetic gains were evaluated based on the Mulamba–Mock index and the developed fuzzy systems. The selection gains were similar for quantitative traits, but fuzzy logic also selected qualitative traits, and thus stands out as a potential tool for kale genetic improvement. The selection of individuals by the fuzzy methodology enables estimated selection gains in a favourable direction for qualitative and quantitative traits, enabling the automation of more accurate and standardised decision-making.

Color analysis and UV-VIS-NIR spectroscopy in the selection of Passiflora edulis hybrids for fresh consumption

Mateus Araújo dos Santos — 2025-10-21

In this study, an alternative method was developed to evaluate fruit and pulp color, using the CIE-L*a*b* kernel space and near-infrared reflectance spectroscopy in predicting the chemical characteristics of Passiflora edulis fruits. Five passion fruit hybrids were evaluated, four with purple-skinned (H09-163, H09-164, H09-166, and H09-125) and one with yellow--skinned (H09-165), in addition to BGP418 (control, yellow-skinned). BGP418 stood out for most physical characters, mainly in the weight of the fruits (224.67 g) and the pulp with seeds (112.77 g). However, its pulp yield was 11% lower compared to other genotypes. Cluster analysis based on fruit skin and pulp color using CIE-L*a*b* space, revealed greater consistency of groups compared to using the conventional method with a color palette. A higher soluble solids content was recorded in fruits with light purple-skinned and light-yellow pulp. Based on the skin and pulp color, the other chemical characteristics did not differ between the groups formed. With UV-VIS-NIR spectra, it was possible to distinguish the genotypes in the 350 and 2,500 nm spectra and the separation between the purple and yellow-skinned l genotypes. However, there was no consistent grouping in relation to the skin and pulp color or relationship with the chemical characteristics of the fruits. The breeding program can utilize the information generated to continue the development of cultivars for fresh consumption.

Expression of apomixis genes during reproductive development in Urochloa decumbens and Urochloa ruziziensis (Poaceae)

Mara Jane da Rocha — 2026-02-26

This study aimed to correlate the developmental stages of the embryo sac with the morphometric traits of spikelets and to characterize the expression of the BbrizRan, BbrizSti1, and BbrizAGL6 genes in Urochloa ruziziensis (sexual) and U. decumbens (apomictic). Data on the length and diameter of spikelets and anatomical sections were also obtained. Gene expression was determined using RT-qPCR in spikelets at megasporogenesis and megagametogenesis. The spikelet length could be used as a reliable morphological marker to discriminate between the two stages in both species. The embryo sacs observed were of the Polygonum type in U. ruziziensis and the Panicum type in U. decumbens. RT-qPCR analysis revealed that the BbrizRan, BbrizSti1, and BbrizAGL6 genes were differentially expressed in the studied species during reproductive development. The BbrizSti1 gene was more highly expressed in U. decumbens (apomictic) than in U. ruziziensis (sexual) during megasporogenesis, while for BbrizRan, U. decumbens showed higher expression than U. ruziziensis during both megasporogenesis and megagametogenesis. An increase in the expression level of BbrizAGL6 was observed in both species at both developmental stages of the embryo sac.

Aspects related to floral morphology and pollen viability for the pollination of self-compatible and self-incompatible pitaya species

Nubia Cassiana Santos — 2026-02-26

Pitaya species can be self-compatible, partially self-compatible, or self-incompatible. Information related to floral biology and pollination is important for identifying the causes of self-incompatibility and the factors that limit self-pollination among pitaya species. This research was carried out to evaluate floral morphology, pollen viability, stigma receptivity, and different pollination methods in genotypes of Selenicereus undatus and S. monacanthus. During the flowering period, the flower buds were selected, identified, and protected in the pre-anthesis stage to evaluate floral morphology, pollen viability, and pollen transfer methods at the time of anthesis. The genotypes had complete flowers and showed differences in floral morphology related to the quantity and coloration of the protective tissues of the flower buds. Herkogamy was more pronounced in S. monacanthus. Anthesis in both species was coincident, with a longer duration in S. undatus. During anthesis, both species presented receptive stigmas and viable pollen grains, with dehiscent anthers before the flowers opened. The S. monacanthus genotype was self-incompatible. Seeds from self-pollination showed lower germination. Manual cross-pollination between the genotypes promoted a high fruit set and the formation of fruit of a high commercial standard.

Functional genetic diversity in popcorn lines (Zea mays L. var. Everta) focusing on productivity through SSR-EST markers

Lavínia Santana Ladeira Gomes — 2026-02-26

Popcorn is a distinct type of maize with a high market demand. In Brazil, there is a shortage of national cultivars that meet production and marketing needs, so seeds are imported, hindering the growth of this sector. Nevertheless, its cultivation is important and can be enhanced with investments in genetic improvement aimed at optimizing characteristics such as productivity. Molecular markers support this type of research: They allow the genetic characterization of lines and inferences about genetic variability. Microsatellites such as simple-sequence repeats (SSRs) are widely used in genetic studies due to their high reproducibility and polymorphism. SSR-expressed sequence tag (EST) markers are microsatellites related to transcribed sequences. Functional variability is linked to the maximization of genetic gains, making the study of these regions valuable. In this context, the present study used SSR-EST markers to characterize the productivity of 47 popcorn lines from the UENF Germplasm Bank, selected for their high performance in previous studies. Young leaves of the lines were collected for DNA extraction, which was used for polymerase chain reaction (PCR) with 30 preselected primers. The amplified material was subjected to capillary electrophoresis for identification and separation of alleles. The data were converted into a dissimilarity matrix, which allowed for the estimation of diversity metrics such as the number of alleles, the polymorphic information content, observed heterozygosity, expected heterozygosity, and the inbreeding coefficient. A total of 94 distinct alleles were detected, with an average of 3.13 alleles per locus, indicating that, although the lines present high levels of allelic fixation and inbreeding, they retain moderate genetic variability for population configuration. A dendrogram created using unweighted pair group method using arithmetic mean revealed an optimal number of six populations. This information provides indications of specific genotypes for crosses that can maximize heterosis in hybridizations to support the improvement program.

Population structure and genetic diversity of traditional sweet cassava accessions in Mato Grosso, Paraná, Santa Catarina and São Paulo States, Brazil

Weslaine de Almeida Macedo — 2026-02-27

With the increasing demand for more productive cultivars that are tolerant or resistant to diseases and pests, the exploration of genetic resources combined with molecular analyses has proven to be an essential research strategy. Through molecular analysis, it is possible to identify and select desirable traits with high precision, increasing the efficiency of breeding programs. This study aimed to analyze the population structure and genetic diversity of traditional sweet cassava accessions collected from rural and peri-urban areas of municipalities in the states of Mato Grosso, Paraná, Santa Catarina, and São Paulo States, Brazil, via microsatellite markers. A total of 227 traditional sweet cassava accessions were evaluated using 29 microsatellite markers. The analysis revealed polymorphisms across all loci, with an average of 3.21 alleles per locus and 12 rare alleles identified within the population, potentially linked to unique genetic traits. The mean polymorphism information content (PIC) value of 0.52 suggests that the markers were moderately to highly informative. The average observed heterozygosity (H_o) was 0.65, whereas the average genetic diversity was 0.60. The sweet cassava accessions were grouped into four subpopulations on the basis of population structure at K = 4. The PhiPT value was 0.13, indicating low to moderate genetic differentiation among the evaluated subpopulations and highlighting their distinct genetic characteristics. The most divergent combinations were observed between the accessions from Western Paraná and Northern Mato Grosso, as well as between accessions from Northern Mato Grosso and Central-Western Santa Catarina. These results are important for addressing aspects related to germplasm conservation and the demands of genetic improvement programs, which benefit from high genetic variability, for the development of new sweet cassava cultivars.

Effects of sodium hypochlorite on seed germination and seedling emergence in Rangpur lime

Antonio Maricélio Borges de Souza — 2025-10-20

Citrus seedlings are typically propagated through grafting, using rootstocks grown from seeds. However, the coating of citrus rootstock seeds can hinder germination. Therefore, applying sodium hypochlorite (NaClO) provides an alternative to manually removing the seed coat, potentially enhancing seed germination and seedling emergence. This study investigates the use of sodium hypochlorite (NaClO) as a scarification agent on freshly harvested Rangpur lime seeds to improve germination and seedling emergence. The experiment employed a completely randomized design with a 3 × 3 factorial arrangement and an additional treatment across four replications. The variables assessed included three NaClO concentrations (0.0% - distilled water; 2.5%, and 5.0% active chlorine) and three soaking durations (3, 6, and 9 hours), with a control of unsoaked seeds retaining their coats. The evaluated parameters were germination rate, first germination count, seedling emergence, speed index, and mean seedling emergence time. Results showed that NaClO effectively degrades the seed coat, with a 2.5% concentration for 6 hours optimizing germination. While NaClO treatment did not alter emergence rates, it reduced the average time to seedling emergence. Conversely, a 5.0% concentration for 9 hours detrimentally affected germination and vigor. Sodium hypochlorite soaking presents a viable alternative for seed coat removal, accelerating germination and emergence processes in Rangpur lime tree seeds, potentially enhancing seedling production efficiency.

Bradyrhizobium japonicum doses and fertilizer from cupuaçu residues: seedling quality, chlorophyll content, and photosynthetic efficiency in Mezilaurus itauba

Aline das Graças Souza — 2025-10-20

This study evaluates the optimal dose for maximum technical efficiency of Bradyrhizobium japonicum (B. japonicum), both with and without a fertilizer derived from cupuaçu residues (FERCup), on the early growth, seedling quality, and physiological metrics of Mezilaurus itauba in the northern Amazon. We assessed several parameters: shoot height (SH, cm), stem diameter (SD, mm), shoot dry mass (SDM, g plant^-1), root dry mass (RDM, g plant^-1), total dry mass (TDM, g plant^-1), Dickson Quality Index (DQI), chlorophyll a (CHL a, μg mL^-1), chlorophyll b (CHL b, μg mL^-1), total chlorophyll (CHL total, μg mL^-1), Nitrogen Balance Index (NBI), specific leaf area (SLA, cm² g^-1), and leaf area ratio (LAR, m² g^-1). A B. japonicum dose of 0.30 mL L^-1, with or without FERCup, enhanced seedling quality and robustness in M. itauba under the study conditions. Including FERCup at these doses significantly improved the morphological traits of the M. itauba seedlings. Additionally, B. japonicum doses of 0.2 and 0.4 mL L^-1 with FERCup positively impacted all physiological indices in M. itauba seedlings 180 days post-transplant.

Inference of leaf nitrogen concentration using machine learning on data resampled to the spectral resolution of Sentinel-2

Maria Clara Rodrigues Simão — 2025-10-20

Nitrogen (N) is among the main nutrients widely used in agriculture worldwide; however, its administration and management can be challenging. Excess nitrogen is harmful to plant health and the environment, requiring effective monitoring of leaf nitrogen concentration (LNC) in field crops. Remote sensing stands out as a valuable tool in this context. This study contributed to the monitoring of LNC by implementing a machine learning algorithm based on the processing of reflectance data from Sentinel-2 (S2) satellites obtained via spectral resampling. For this purpose, five independent datasets containing leaf reflectance measurements collected by spectroradiometers were resampled to the spectral resolution of the sensors onboard the S2 satellites. LNC prediction models were developed from the resampled datasets, using Support Vector Regression (SVR) and Random Forest Regression (RFR), with 75% of the data from each set used to train a model and the remaining 25% for validation. The models demonstrated good predictive power, with the Root Mean Squared Error (RMSE) ranging from 0.39 to 0.94%. Furthermore, this study investigated the transferability of the models' predictive power by using 100% of the data from each set for training and validating predictions on the other sets. To improve transferability, the Transfer Component Analysis (TCA) technique was applied to adapt domains between the sets. This analysis revealed favorable results, especially with the TCA-SVR and TCA-RFR combinations, highlighting a greater capacity to extract transferable spectral features between different leaf reflectance datasets. It was concluded that spectral resampling does not hinder the development of effective LNC prediction models. Aligning this resampling with the resolution of Sentinel-2 sensors, resulted in more efficient monitoring of LNC, eliminating the need to individually reference each sampling point. This approach simplified the monitoring process, reduced both time and costs, and was directly beneficial to producers.

Non-destructive method for predicting the area and weight of red pitaya cladodes using linear dimensions

Ivanice da Silva Santos — 2025-10-21

The leaf area estimation of crops is a critical analysis because it indicates the photosynthetically active area of the plant. However, some methods are more expensive and difficult to apply to crops, such as pitaya. Thus, the objective of the present work was to determine a non-destructive method of estimating the area and weight of pitaya cladodes using linear dimensions. In an experimental orchard, 101 pitaya cladodes of the species Selenicereus undatus were collected, and the length (L), width (W), cladode area (CA), fresh mass (FM) and dry mass (DM) of the cladodes were measured. The product between the cladodes’ length and width (LW) was then calculated. Linear, non-intercept linear and power models were used to predict the area and weight of cladodes using allometric equations. The criteria for choosing the best equations were based on Pearson’s coefficients of determination and correlation, Willmott’s agreement index, Akaike’s information criterion, root mean squared error and mean absolute error. The equations constructed with the power and linear model were the most suitable for predicting cladode area (CA = 5.577 * LW^0.541), cladode fresh mass (FM = 8.50 * W^1.138) and cladode dry mass (MD = 3.03 + 1.74 * W). Thus, it was possible to construct a non-destructive and reliable method for predicting the area and weight of pitaya cladodes using the linear dimensions of the cladodes (length and width).

Sewage sludge in the production of chrysanthemum (Dendranthema grandiflora) and petunia (petunia x hybrida) seedlings

Santuza Silverio Hermes Dias — 2025-10-21

Sewage sludge generated from wastewater treatment plants is an environmental and economic liability that burdens not only waste management companies, but the society at large, because it causes environmental damage. Therefore, this study aimed to seek an alternative to the destination of this sludge, such as using it as a substrate to produce chrysanthemum (Dendranthema grandiflora) and petúnia (petunia x hybrid) seedlings. The sludge was collected at CASAN, Florianópolis (SC-Brazil), and subjected to solar drying for later application in proportions of 0, 5, 10, and 25%, together with soil collected from the Ressacada Farm Experimental Station, and used as inoculum for arbuscular mycorrhizal fungi. The parameters used in the analyses were plant height (cm), root length (cm), production of aerial part dry matter, production of root dry matter (g), nitrogen content in the aerial part (g kg^-1), nitrogen accumulation in the aerial part (mg plant^-1), phosphorus content in the aerial part (g kg^-1), phosphorus accumulation in the aerial part (mg plant ^-1), soil arbuscular mycorrhizal fungi spore count (in 50 cm of soil), mycorrhizal colonization (%), and pH of the substrate (pre- and post-treatment). The study showed that solar drying is an efficient method of eliminating pathogens, and the sludge was classified as proper for agricultural application. The results showed that the best dosages of sludge for the growth of chrysanthemum and petunia varied from 5 to 13%, and 13 to 18%, respectively. These concentrations provided the best yield for all variables tested, except mycorrhizal colonization and spore counting that decreased as the sludge concentration increased.

Defoliation management and boron application as a strategy to reduce poor fruit set and improve the quality of ‘Merlot’ grapes

Everson Fernando Suzin — 2025-10-21

‘Merlot’ grapevines hold significant importance in Brazilian viticulture, particularly within the high-altitude region of Santa Catarina. However, they often experience a physiological disorder known as poor fruit set and shot berries, which results in clusters with few berries, uneven ripening, and reduced productivity. Therefore, this study evaluated the effectiveness of different defoliation and boron application strategies in mitigating poor fruit set. The evaluated treatments included: i) 3 defoliations with boron application at phenological stages 17 (developed inflorescence), 23 (full flowering), and 35 (beginning of maturation); ii) 3 defoliations without boron application at the same phenological stages; iii) 1 defoliation treatment with boron application at full flowering; iv) 1 defoliation treatment with boron application at the beginning of maturation; and v) a control with no defoliation but with boron application. Berry drop evaluations were conducted during the 2023 and 2024 harvests. Our findings showed that performing 3 defoliations at the developed inflorescence, full flowering, and the beginning of maturation stages did not reduce poor fruit set in ‘Merlot’ grapes cultivated in the Serra Catarinense region. However, these treatments were associated with increased total polyphenol and anthocyanin contents, improved color parameters, and enhanced color intensity in the wine. Late defoliation treatments decreased color intensity and anthocyanin and total polyphenol contents in ‘Merlot’ wines.

Dry matter and minerals in the aerial part of the banana tree ‘BRS SCS Belluna’

Hebert Teixeira Cândido — 2025-10-21

Brazil is a large banana producer, and technological advances have resulted in gains in national productivity. Developing new cultivars is part of the technological package that ensures the success of this activity. Among these cultivars, the ‘BRS SCS Belluna’ banana tree launched in 2016 through a partnership between Embrapa and Epagri, presents important agronomic characteristics for the sector and appears to be an option for market diversification with its small, sweet fruit. Banana trees are plants with high rates of phytomass production, which is regulated by the mineral distribution between their organs and influences mineral cycling and export. Thus, the objective of this study was to evaluate the phytomass and minerals in the aerial part of the BRS SCS Belluna banana tree. Two production cycles were evaluated. The organs and tissues of the aerial part were separated into the pseudostem, inflorescence, stalk, leaves, peel, and pulp. The pulp had the highest dry matter content, and the pseudostem had the highest accumulation, resulting in an average cycling of 64% of the produced dry matter. Potassium and manganese were the most accumulated macro- and micronutrients in the organs and tissues evaluated, except for the leaves, where nitrogen and calcium were predominant. In general, the inflorescences and leaves had the highest mineral concentrations, whereas the pseudostem had the highest exports. The highest cycling rates were observed for calcium and magnesium (macronutrients) and manganese (micronutrient). The highest removal rates were observed for nitrogen and phosphorus (macronutrients) and boron (micronutrient).

Performance of pineapple cultivars inoculated with Fusarium guttiforme isolates on different substrates

Dayane Castro Silva — 2025-10-21

Fusariosis in pineapples causes significant losses to producers. Knowing practices that reduce disease severity is important, as cultivation in Brazil mainly relies on the susceptible cultivar ‘Pérola’. Therefore, this study aimed to analyse the vegetative development and severity of fusariosis in different pineapple cultivars inoculated with Fusarium guttiforme isolates in various substrates. Isolates were collected and inoculated into ‘Pérola’ and ‘BRS Imperial’ cultivars planted in different substrates. Vegetative characteristics and disease severity were assessed. Evaluations were carried out fortnightly over 120 days. A randomised block design was used in a triple factorial arrangement 5 x 2 x 3 (five isolates x two cultivars x three substrates). Data were analysed using Sisvar software. The cultivars showed distinct vegetative development, with ‘Pérola’ being susceptible to all isolates, displaying reduced plant height, leaf D length and width, and number of active leaves. The pineapple leaf D is used to measure plant growth and nutritional status. Isolates 3 and 7 led to the death of several ‘Pérola’ plants. The substrate that favoured the highest disease severity was composed of sand and soil in a 3:1 ratio. The ‘‘BRS Imperial’’ cultivar showed resistance to all isolates and substrates. Finally, pineapple cultivation will develop better in substrates with favourable physico-chemical compositions and proper fertilisation. The ‘BRS Imperial’ cultivar is viable for producers as it is resistant to fusariosis and can withstand abiotic stress conditions.

Nitrogen fertilization, fungicide application, and genetic resistance for the management of diseases on wheat

Andrea Román Ramos — 2025-10-21

Nitrogen (N) fertilization is a common practice to increase grain yield worldwide. This study aimed to determine the effects of three N rates (70, 130, and 200 kg ha⁻¹, referred to as low, recommended, and high, respectively) and a pre-mix fungicide (bixafen + prothioconazole + trifloxystrobin) on the disease intensity and grain yield of 2 early-maturing wheat cultivars named as TBIO Audaz and TBIO Tibagi. Two field experiments were conducted during the 2019 and 2020 growing seasons using the split–split plot design. Tan spot, powdery mildew, leaf rust, and Fusarium head blight (FHB) were the primary diseases observed. The recommended and high N rates reduced the area under the disease progress curve (AUDPC) for tan spot. However, the AUDPC for powdery mildew increased with high N for both cultivars, but N rates did not affect leaf rust or FHB. The use of early maturing wheat cultivars did not prevent the occurrence of FHB damage, except on plants from cultivar TBIO Audaz known to be moderately resistant. When combined with N fertilization, fungicide application reduced the AUDPC for tan spot, powdery mildew, leaf rust, and FHB by 31, 33, 75, and 40%, respectively, compared to the non-treated control. The cultivar × fungicide and cultivar × N interactions were significant (p < 0.05) for AUDPCs and yield variables. Both the recommended and high N rates similarly increased the yield, health area duration, and tan spot control at the same level compared to the low N rate. These findings combined with economic and cost-efficiency analyses suggest that using a moderately resistant cultivar with recommended N rates help to maintain adequate N use efficiency and economic returns to growers.

Phenotypic evaluation to define optimal sowing time for upland rice lines in the second crop in Campo das Vertentes region

Arsénio Daniel Ivo Mulhanga — 2026-02-26

Rice is a staple food for more than half of the world’s population. In Brazil, upland rice cultivation in the southeastern region faces competition from soybean due to its higher profitability in recent years. In this context, developing more competitive rice lines and expanding the sowing window, such as incorporating rice into the second season, can enhance its integration into cropping systems. This study aimed to evaluate the performance of elite upland rice lines under different sowing dates during the second crop season. Field experiments were conducted in Lavras, Minas Gerais State, Brazil, across 4 sowing dates in 7-day intervals, starting on January 28, 2022. Eight genotypes were evaluated in a randomized block design with a two-way factorial scheme (8 genotypes × 4 sowing dates). The assessed traits included the number of days to flowering (NDFL), plant height (PH), tolerance to Helminthosporium oryzae, and grain yield (GY). The data were analyzed using mixed models based on the restricted maximum likelihood/best linear unbiased predictor. The results revealed significant genetic variability for NDFL and PH as well as significant sowing date effects on NDFL, PH, and GY. A sharp decline in performance was observed across sowing dates, with an increase of 24 days in NDFL, a 14% reduction in PH, and sterility rates reaching 100% at the last sowing. These findings highlight the importance of genotype selection and optimal sowing timing to sustain upland rice production during the second crop season.

Soybean canopy estimation using different image capture methods

Fernanda Trentin — 2026-02-26

The determination of crop canopy characteristics (vegetation cover, leaf area, and leaf area index) is usually obtained through costly methods or methods that require training and time. Based on this, the aim of this work was to determine whether different methods and angles for capturing images using a smartphone camera and fisheye lenses can predict information about the soybean canopy in a practical, fast, and low-cost way. Different methods of capturing images were carried out throughout the soybean cycle using smartphones, attached fisheye lenses, manual normalized difference vegetation index (NDVI) reading equipment, and destructive plant evaluations. The captured images were analyzed in the Canopeo app to determine the green cover fraction. Pearson’s correlation and regression models were used to study the association between NDVI and leaf area index (LAI). The data were compared in the vegetative and reproductive stage segments and throughout the crop cycle to determine whether the image acquisition methods were capable of estimating the variations at each crop stage. With the exception of images captured during the soybean’s reproductive stage, all methods proved to be suitable for evaluations and comparisons using the Canopeo app. Capturing images 1 m above the canopy and video were the methods that best estimated the NDVI and LAI of soybeans.

Lignin content, morphoanatomical traits and antioxidant activity as determinants of soybean seed storage tolerance and quality

Amanda Carvalho Penido Nardelli — 2026-02-26

The storage of soybean seeds is a critical aspect of the production process, making it essential for genotypes to show tolerance during this phase to maintain seed quality. This study aimed to examine and correlate lignin content in the seed coat, enzyme activity expression, and morphoanatomical characteristics of soybean cultivars with the preservation of physiological quality and storage tolerance. Eight soybean cultivars were selected, produced, and harvested under uniform edaphoclimatic conditions. Physiological quality assessments were conducted at six storage intervals: 0, 60, 120, 180, 240, and 360 days. Evaluations included tests for germination, emergence, accelerated aging, electrical conductivity, and lignin content in the seed coat. Additionally, biochemical and enzymatic analyses of antioxidant metabolism and morphoanatomical examinations were performed using light microscopy on seeds stored for 0 and 360 days. The experiment used an 8 × 6 factorial arrangement, encompassing eight cultivars and six storage periods. For the enzymatic and morphoanatomical analyses, a 4 × 2 factorial design was employed, involving four cultivars and two storage durations. The results showed that genotype significantly influenced the tolerance of soybean seeds to extended storage periods. Seeds proving high physiological quality and storage resilience exhibited reduced hydrogen peroxide accumulation and diminished lipid peroxidation. Furthermore, morphoanatomical analyses provide a promising method for selecting genotypes with enhanced physiological quality and storage tolerance.

Ora-pro-nóbis (Pereskia aculeata Mill.) propagated by seeds and cuttings under water deficit and biological indicators of soil quality

Lucas Lenin Resende de Assis — 2026-02-26

Ora-pro-nóbis (Pereskia aculeata Mill.) is a protein-rich member of the Cactaceae with great potential for cultivation in regions where water can be a limiting factor. The aim of this study was to verify the tolerance of this species to water deficiency and determine how microbial biomass and soil respiration are affected under these conditions. Five treatments were tested, namely control and irrigation suspension for 7, 14, 21, and 28 consecutive days, in plants propagated by seeds and cuttings. The decrease in soil moisture and soil water potential (Ψ_s) after 28 days of water restriction highlighted the severe impact of a lack of water on plants, especially those propagated by cuttings, which showed greater susceptibility to water stress (leaf potential -2.84 MPa). Seedlings, although affected in terms of root development and fresh mass at 28 days (leaf potential of -1.59 MPa), showed advantages in terms of shoot fresh matter and plant diameter, suggesting that propagation by seeds and root development are crucial for water stress resistance. The microbial biomass carbon, in general did not vary among the irrigation suspensions times both in plants propagated by seeds and cuttings, reinforcing the importance of microbial adaptation to stressful conditions.

Silicon sources can promote growth and induce systemic resistance at the microscale to control fungal diseases in sugarcane

Kauê Vinícius Cerilo — 2026-02-26

Sugarcane is a crop of great economic importance for Brazil. However, it is affected by several fungal foliar diseases that compromise its agricultural productivity. The use of elicitor agents can induce and enhance plant resistance, in addition to reducing the need for pesticides, thus promoting sustainable production. Our hypothesis was that fertilization with silicon as a constituent element of the cell wall can create greater resistance and control of foliar fungal infections responsible for red rot and ringspot diseases and has a greater effect when combined with genetic resistance. The objective was to apply and investigate the potential of silicon Si as an inducer of systemic resistance and modulator of phenotype for the control of fungi in two sugarcane cultivars, RB867515, which is recognized for its greater productivity in the Iturama-Minas Gerais region, and the transgenic cultivar CTC9001BT, which has resistance to the sugarcane borer, by analyses of morphophysiological and micromorphometric parameters. The greatest discovery of this scientific research was the positive effect of greater systemic resistance of sugarcane with different management techniques: the application of Si sources resulted in the genetic transformation of plants, as observed in the CTC9001BT cultivar with higher doses of Si. Therefore, silicon may be an option for integrated pest and disease management. However, some significant differences observed in the biometric, anatomical and micromorphometric analyses may result from genetic differences between the cultivars studied.

Effects of drying on the bioactive compounds in organic sweet potatoes (Ipomoea batatas)

Okelyton Ayres Pacheco — 2026-02-26

Sweet potato (Ipomoea batatas L.) is a source of vitamin A, carbohydrates, organic acids, and minerals. It is rich in bioactive compounds, making it a very healthy food. Indeed, it helps in the prevention of various diseases such as cardiovascular diseases, certain types of cancer, and in controlling the glycemic index of people with diabetes. Additionally, it provides nutrients for at-risk groups, such as children and pregnant women with deficiencies in magnesium and vitamin A. In its natural form, sweet potatoes have high water activity, making them highly perishable and reducing their shelf life. This study aimed to evaluate the influence of the drying process at different temperatures (50, 60, and 70°C) and thicknesses (1, 2, and 3 mm) on the antioxidant content and phenolic compounds of two sweet potato cultivars: BDI (Brasilândia) and BDII (not cataloged). The drying process was evaluated based on 10 mathematical models, comparing the coefficient of determination (R²), chi-square (χ²) value, and root mean squared error (RMSE). The Page model stood out for the BDI cultivar and the diffusion approximation and Page models were significant for the BDII cultivar. The total phenolic content ranged from 71.67 to 99.33 mg gallic acid equivalents 100 g^-1. The 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) methods were used to quantify antioxidant activity, with values ranging from 21.93 to 51.53 µmol Trolox 100 g^-1 and 656.34 to 1021 µM ferrous sulfate 100 g^-1, respectively. A drying temperature of 70°C combined with a thickness of 1 mm required a shorter drying time to reach the equilibrium moisture content, between 2 and 3 hours.

Correction of distortions in image analysis for improved phenotyping of tomato fruit

Nayany Gomes Rabelo — 2026-02-26

With technological advancements, particularly in image analysis, phenotyping can now be conducted more accurately, impartially, and non-destructively. However, distortions caused by different camera angles as well as environmental factors, such as lighting, lead to inaccurate results in image analysis. Therefore, a method for correcting these distortions is necessary to achieve more precise outcomes. The objective of this study was to develop an algorithm that corrects image distortion and improves tomato fruit phenotyping and to determine its efficiency. A photographic studio and a smartphone were used to capture the images. To test the developed algorithm, twelve 4 × 4 cm black squares were printed on A4 sheets, with four of these sheets placed inside the studio. Additionally, eight 3 × 3 cm yellow square sheets were used as reference objects to correct distortions. A total of 40 images were obtained with different camera angles. A multiple regression model was then adjusted and tested for each image to obtain a correction factor for distortions caused by varying camera angles. In the test images, higher estimates for the coefficient of variation and mean squared error were observed at the edges and lower ones at the center. After correcting the images using the adjusted regression model, uniformity in the estimates was achieved. The same behavior was observed when validating the model with images of tomato fruit. The coefficient of determination of the adjusted model was over 80%, indicating a high fit for the selected model. Therefore, the image distortion correction methodology ensures more accurate results in tomato fruit phenotyping.

Physical properties of Ferralsols in response to sugarcane cultivation in the state of Goiás, Brazil

Gustavo Cassiano da Silva — 2025-10-21

For sugarcane production, soil physical properties are essential indicators of crop growth, development and sustainable productivity. This study evaluated the physical properties of different textural classes of Latossolos Vermelhos distróficos (Ferralsols) under sugarcane cultivation, with and without vinasse application. The study was conducted under the soil, climate and management conditions of the counties of Quirinópolis and Goianésia, both in Goiás State, Brazil. In Quirinópolis, variety RB 867515 was planted and evaluated over 1, 3, and 7 consecutive sugarcane cycles. In Goianésia, cv. CTC4 was cultivated and assessed in 1, 2, and 4 cycles. At both locations, a plot with native vegetation was used as reference. To evaluate bulk density, macroporosity, microporosity, total porosity, macro- to micropore ratio, soil aeration capacity and relative bulk density, soil samples were collected from the 0.0-0.10, 0.10-0.20, 0.20-0.30, and 0.40-0.50 m layers. It was found that soil physical properties were affected by the crop cycles, and in Quirinópolis, the plots in the first and third cycles were most affected by increased bulk density. In Goianésia, the physical properties were negatively affected in the first and second sugarcane cycles. Regardless of the soil texture and vinasse application, the soil physical properties were negatively affected by the implementation or renewal of sugarcane plantations up to the third consecutive sugarcane cycle, but improved from the fourth to the seventh cycle without sugarcane renewal.

Carbon and nitrogen stocks and organic fractions in areas under different land uses in the cerrado

Adilson Alves Costa — 2026-02-26

The replacement of native vegetation with nonnative vegetation for different land uses, which is a consequence of the intensification and expansion of agricultural production, significantly alters the dynamics of soil organic fractions. The aim of this study was to evaluate the changes in carbon and nitrogen contents and stocks, as well as the chemical fractions of organic matter, caused by different land uses in Cerrado areas. The selected areas were conventional tillage (CTS), no-tillage (NTS), eucalyptus cultivation (EC) and native Cerrado vegetation (NC) in the regions of Barreiras and Luís Eduardo Magalhães, Bahia State, Brazil. The highest carbon contents and stocks were found under NTS up to 10 cm, and these values, as well as those of EC, were equal to those found under NC below 10 cm. The same phenomenon was not verified for the nitrogen contents and stocks in the soil up to 20 cm deep. The values of carbon in the fulvic acid fraction (C-FAF) under NTS and EC were equal to those of NC up to 10 cm deep, but only EC was equal to NC below this layer. At the 10–20 cm depth, the C-FAF increased by 1.23 g kg^-1 and 0.95 g kg^-1under NTS compared with those under EC and NC, respectively. With respect to the correlations between carbon fractionation and total organic carbon, the nonextractable humic fraction (C-HUM) had the strongest correlation with the TOC content, with r² = 96 (p < 0.001). Over time, the input of residues in the NTS and EC areas contributed to increasing soil carbon stocks and organic matter quality, with a recovery of up to 84% of the carbon in humin.