Acta Scientiarum. Agronomy

Estimation of optimal plot size for chickpea experiments using Bayesian approach with prior information

2025-03-11T17:29:25+00:00

Heterogeneity among experimental units can introduce experimental errors, necessitating the use of techniques that enhance statistical inferences to address this issue. One effective approach is determining the optimal plot size, which can reduce experimental error. While frequentist methods are commonly employed for this purpose, Bayesian approaches offer distinct advantages. Therefore, our objective was to estimate the optimal plot size for chickpea experiments using the Bayesian approach and compare the results with those from the frequentist approach. We conducted two control experiments (with no treatments) involving eight cultivation rows, each spanning seven meters in length, with 50 cm spacing between rows and 10 cm spacing between plants. We evaluated the central six rows, totaling 60 plants per cultivation row. At the end of the growth cycle, we assessed seed count, seed weight, harvest index, and shoot dry mass. Data collection was conducted at the individual plant level. We determined the optimal number of plots using both the frequentist approach (modified maximum curvature method) and Bayesian approach, employing informative and uninformative prior distributions. The optimal plot size varied depending on the specific experiments and the variables under analysis. However, there was consensus in the estimation of the optimal experimental plot size between the two approaches. We recommend using 15 plants as the optimal plot size for chickpea cultivation.

Modeling nitrogen loss due to ammonia volatilization in fertilizers applied to coffee plants

2025-04-22T17:44:07+00:00

The coffee tree has a strong dependence on nitrogen (N), which influences the nutritional aspect and plant productivity. The knowledge of the nutritional behavior of coffee crops, as well as the pattern of nutrient release and loss, contribute to the appropriate crop management, influencing quality, productivity and minimizing economic losses. Therefore, the objective of this article is to select the non-linear model that best describes nitrogen losses due to ammonia (NH₃) volatilization, in seven conventional and increased efficiency fertilizers, applied in three installments to coffee plants and indicate the fertilizers that presented the highest and lowest nitrogen losses due to NH₃ volatilization. The data come from an experiment carried out during the 2015/2016 harvest at the Coffee Innovation Agency (INOVACAFÉ) of the Federal University of Lavras, in a randomized block design with 3 replications of 7 treatments (nitrogen fertilizers). The estimation method used was the least squares method (MMQ), with the Gauss-Newton convergence algorithm as the iterative method. As diagnostic measures to determine the best model, the adjusted coefficient of determination (R2aj), residual standard deviation (RSD), Akaike information criterion (AIC) and mean absolute deviation (MAD) were used. It was verified that all models exhibited good adjustments, however, the Brody and Logistic models stood out in describing the accumulated nitrogen losses, due to ammonia volatilization, in relation to the seven treatments applied and evaluated. It was found that ammonium nitrate and ammonium sulfate fertilizers presented the lowest N losses, while Prilled Urea and Urea + anionic polymer contribute the greatest losses due to the volatilization of NH₃, in the three fertilizations on coffee plants.

AgroR: An R package and a Shiny interface for agricultural experiment analysis

2025-04-22T17:43:45+00:00

Statistical analysis is central to agricultural research, but the complexity of statistical methodologies and programming languages, such as R, often poses challenges for researchers. To address these difficulties, we present AgroR, a comprehensive R package and Shiny web application (https://uel.br/fisher.uel.br/AgroR_shiny) designed to streamline the analysis of agricultural experiments. AgroR supports a wide range of experimental designs, offering tools for analysis of variance, multiple comparison tests, and assumption validation, as well as functions for exploratory data analysis and graphical representation. The package is built for accessibility, allowing users with limited programming skills to perform advanced statistical analyses using an intuitive interface. The Shiny application enhances usability by providing a graphical interface that simplifies the running of statistical tests and visualization of results. AgroR includes functions for analyzing complex experimental designs, such as factorial and split-plot designs, and offers additional tools for graphical outputs and dataset management. Available through the CRAN repository and accessible via a web browser, AgroR has been widely adopted, with thousands of downloads and citations across the scientific literature. AgroR significantly lowers the barriers to statistical analysis in agricultural research by providing a user-friendly interface and robust statistical capabilities, thereby enabling more accurate and reliable conclusions.

Alternatives for simulating and modeling simplified insect feeding eletropenetrography discrete data

2025-07-08T19:53:21+00:00

The study of insect feeding behavior using electropenetrography (EPG) typically involves analyzing complex data. EPG data comprises a temporal sequence of behaviors summarized using a collection of counts, durations, and sequential variables. These variables can be counts, means, percentages, or linear combinations of behaviors. This results in numerous variables being correlated to a certain degree. Consequently, statistical analysis is rendered complex, particularly in terms of model fitting and selection. This study proposed a statistical approach to simulate overdispersed correlated count data based on a previous comparative experiment to monitor the feeding behavior of untreated Euschistus heros versus E. heros treated with an entomopathogen. The waveforms included non-feeding (Z), pathway (Eh1), laceration/maceration of endosperm tissue (Eh3a), short ingestion events of lacerated/macerated endosperm tissue (Eh3b), xylem sap ingestion (Eh2), and ingestion from an unknown location (Eh4). Simulated scenarios involved the creation of differences between groups of insects based on the total number of events or the proportion of events of Z. Several statistical models were then fitted to the simulated data and evaluated based on goodness-of-fit, type-I error rate, and power analysis. The multinomial model exhibited the lowest type-I error rate and was more sensitive in detecting higher (>1.35x) differences between groups. Only the multinomial model achieved a power greater than 0.8. Conversely, models such as the Poisson and normal models exhibited limitations such as inflated type-I error rates in the presence of overdispersion. Among the univariate models, the mixed model exhibited the best fit.

Statistical modeling of vigor ratings in ruzigrass breeding

2025-09-04T11:21:26+00:00

Ruzigass (Urochloa ruziziensis) is a forage crop with high agronomic and nutritional value. Plant breeders often assess ruzigrass phenotypic traits via vigor ratings. The analyses of these categorical data often fail to meet the usual statistical assumptions. In this study, we compared four fittings of linear models for vigor rating analyses: i) a linear mixed model for the original scale (LMM), ii) a linear mixed model for a Box–Cox transformed scale (BCLMM), iii) a multinomial generalized mixed model using a probit link function, also known as threshold model (GLMM), and iv) a hierarchical Bayesian model, also referred to as a Bayesian threshold model (HBM). Additionally, biomass yield was assessed, and the indirect selection of high-performing genotypes was evaluated. The experimental design included 2,204 ruzigrass genotypes randomized into augmented blocks. Six graders visually assessed each plot using a rating scale. Fitting methods were sampled from three scenarios, employing one, three, or six graders. A nonnull genetic variance component was detected for vigor and biomass yield traits. Except for BCLMM, the methods for analyzing vigor ratings were correlated. The correlations and coincidence indices for selecting genotypes increased with the number of graders. The analysis of vigor ratings under Gaussian approximations is riskier when a single grader is used to evaluate genotypes. The GLMM and HBM perform similarly and are more recommended and suitable analyses of vigor ratings when selecting high-performing ruzigrass genotypes.

MultivariateAnalysis: um pacote R para análise multivariada.

2025-09-05T13:04:45+00:00

Statistical analysis is essential in research. As modern production processes evolve, the increasing volume of data needing processing has demanded techniques like multivariate analysis for simultaneous data handling. Multivariate analyses are typically complex and often require statistical software. The MultivariateAnalysis package, an R package available on the CRAN platform, was developed to facilitate these analyses. Introduced in 2021 by researcher Alcinei Místico Azevedo, it encompasses techniques such as principal component analysis, principal coordinate analysis, hierarchical clustering, Mantel correlation, dendrograms, canonical variables, dissimilarity measurements, and multivariate variance analysis. This paper aims to detail the MultivariateAnalysis package, offering a practical guide from initial steps to results, enhancing user understanding of the package's functions and potential applications. Its open-source code permits function additions. As of 2024, MultivariateAnalysis has reached version 5.0, featuring enhancements in graphical functions that provide a simple, flexible, and intuitive workspace applicable across various knowledge domains

Thermodynamic properties of moisture sorption of soybean (Glycine max L.) grains

2025-04-22T17:44:09+00:00

This study investigated the thermodynamic properties of water sorption in soybean using the DM 68I69 Ipro variety from Campo Verde, Mato Grosso, Brazil. Grains with initial moisture contents of 21.95% (w.b.) and 3.50% (w.b.) were used for desorption and adsorption analyses, respectively. The static-gravimetric method determined equilibrium moisture content at various temperatures (10, 20, 30, 40, and 50°C) and relative humidity (between 0.11 and 0.92 ± 2%). The Modified Halsey model quantified the hygroscopicity of soybean. Key findings include: (a) desorption equilibrium moisture content exceeded adsorption values, demonstrating hysteresis; (b) decreasing equilibrium moisture content increased the energy required for water removal and its release during adsorption; (c) differential entropy of desorption and adsorption increased with decreasing equilibrium moisture content; (d) Gibbs free energy decreased with increasing temperature for both desorption and adsorption. The enthalpy-entropy compensation theory effectively described the observed phenomena.

Diversity and abundance of bees in Passiflora edulis Sims (Passifloraceae) orchard, associated with Solanum lycocarpum St. Hill. (Solanaceae)

2025-03-11T17:29:14+00:00

Brazil is the third-largest producer of fruits in the world, with yellow passion fruit (Passiflora edulis) as one of its main crops. This species requires cross-pollination, with Xylocopa bees being the primary pollinators due to its self-incompatibility. The presence of Solanum lycocarpum close to passion fruit orchards can serve, due their flowers, as an attraction for pollinating bees, improving the production of the crop. Thus, the objectives of this study were to: i) investigate whether the planting of S. lycocarpum close to the passion fruit orchard increased the richness and abundance of bees; ii) evaluate whether the implementation of trap nests in the passion fruit orchard and close to S. lycocarpum attracted bees to nests in this location; iii) record the time of greatest foraging activity of Xylocopa frontalis in the passion fruit orchard; and iv) quantify the number of natural nests of X. frontalis in the passion fruit orchard during the experimental period. A total of 48 seedlings of S. lycocarpum were planted and divided into two rows along the eastern border of the yellow passion fruit crop. Bees were recorded for 15 minutes each hour from 8:30 am to 3:30 pm. During the remaining 45 minutes, the posts were inspected for natural bee nests. The frequency, abundance, species richness, and indices of Shannon-Winner, Simpson, and Pielou equitability indices were assessed. The most common species were X. frontalis, Apis mellifera, and Trigona spinipes. The flowering of S. lycocarpum near passion fruit orchards positively influenced the increase in the number of nests and species richness of pollinating bees, indicating that this plant, close to passion fruit orchards, can contribute to fruit production. Finally, we showed the preferred times for bee foraging and the period in which insecticide application should be avoided.

Evaluation of soil fauna diversity in maize crops using Shannon, Margalef, and Pielou indices

2025-03-11T17:28:51+00:00

Soil organisms are vital for soil quality and can indicate environmental conditions. This study aimed to understand the diversity of soil fauna and its connection to plant residue decomposition and maize grain yield across various locations and crop seasons in a subtropical setting. We conducted experiments in Frederico Westphalen, Santa Maria, and São Vicente do Sul, Rio Grande do Sul State, Brazil, during two crop seasons in 2020/2021, totalling six experiments. We assessed parameters such as plant residue decomposition rate, soil fauna abundance, and grain yield. Results showed significant variations in decomposition rate, fauna abundance, and diversity measures (Shannon, Margalef, and Pielou indices, plus relative frequency) across environments. Four taxonomic groups comprised over 80% of collected individuals, with Araneae and Coleoptera showing more than half of relative frequency Our analysis revealed that areas with higher grain yields had faster decomposition rates, suggesting they fostered greater organism activity and nutrient cycling, indicating their potential as soil quality indicators.

Development of warning systems for Phoma leaf spot in coffee

2025-07-08T19:53:25+00:00

Statistical models can help in decision-making for the control of plant diseases, leading to less use of inputs, greater economy, and less negative environmental impact. Thus, this study aimed to use environmental variables to fit multiple linear regression (MLR) models for estimating the Phoma leaf spot incidence in coffee to develop a warning system. The experiment was conducted over two years (September 2013 to August 2015) with monthly disease assessments in the Coffea arabica L. cultivar “Catucaí amarelo 2SL”. A regular grid of 7.65 ha with 85 points delimited the area, with the points spaced 30 x 30 m. The incidence progress curve was constructed by considering the overall mean of the 85 points in each month. Fifty-two environmental variables were generated using an automatic station installed in the crop, and these variables were used in the development of the MLR models. A total of 126 models were fit, of which four were more successful in estimating disease dynamics over time. Two of these models allowed the acquisition of estimated values for disease incidence two weeks prior to the disease assessments, with high precision and accuracy. Nowadays the disease management has been performed exclusively with the use of fixed spraying schedules of fungicides. The models obtained in our research can contribute to sustainability of coffee production, to avoid unnecessary use of fungicides and become coffee cultivation more profitable.

Efficacy of air-assist technology and auxiliary boom for fungicide application in soybean fields

2025-07-08T19:52:53+00:00

This study assessed the effectiveness of air-assist technology and auxiliary booms compared to conventional ground boom sprayers in disease control and yield enhancement in soybean (Glycine max) crops. Conducted in Campos Gerais, Paraná State, Brazil over two cropping seasons, the experiment used a randomized block design with four treatments and eight replicates: i) control (no fungicide application on soybean plants), ii) conventional ground boom sprayer, iii) air-assist technology booms, and iv) auxiliary booms sprayers. Analyses focused on disease incidence and severity, plant physiological traits, and yield components. Results indicated that plots without chemical control exhibited higher disease incidence and severity, while fungicide application methods showed no significant differences. Additionally, diseases did not markedly influence the physiological characteristics of the plants. The lack of disease control notably diminished yield potential, but neither auxiliary nor air-assist technologies significantly outperformed the conventional sprayer in enhancing crop yield parameters.

Influence of growing seasons on sweet potato genotype selection for animal feeding

2025-03-11T17:29:21+00:00

Environmental conditions significantly impact the performance of sweet potato genotypes, necessitating the study of genotype x environment (GE) interactions to select genotypes adaptable to varying cultivation conditions. This study aimed to assess GE interactions in sweet potatoes for animal feed and identify high-performance genotypes suitable for different seasons. We conducted two tests during the Brazilian winter of 2019 and summer of 2020. Employing a partially balanced triple lattice experimental design with 100 treatments (92 sweet potato genotypes and eight controls) and three replications, we measured vine green matter yield (VGMY), percentage vine dry matter (PVDM), vine dry matter yield (VDMY), percentage of root dry matter (PRDM), and roots dry matter yield (RDMY). We ranked genotypes, highlighting the best performers for individual and combined seasons. Significant differences in VGMY, PRDM, and RDMY were observed for GE interaction. VGMY, VDMY, and PRDM favored the summer season, while PVDM and RDMY performed better in the winter season. Genotypes 2018-31-713, 2018-72-1438, 2018-31-666, 2018-12-252, 2018-19-461, 2018-19-389, 2018-38-946, 2018-31-689, and 2018-37-864 proved most suitable for VGMY and VDMY across growing seasons. Genotypes 2018-28-514, 2018-15-268, and 2018-19-443 demonstrated potential in percentage vine dry matter. Genotypes 2018-31-666, 2018-72-1438, and 2018-15-277 are recommended for PRDM in both seasons. Genotypes 2018-19-464, 2018-28-556, 2018-55-1154, 2018-28-543, 2018-53-1038, 2018-72-1432, and 2018-19-443 exhibited greater potential for RDMY, making them ideal for animal feed in both growing seasons.

Two-step genomic prediction using artificial neural networks - an effective strategy for reducing computational costs and increasing prediction accuracy

2025-03-11T17:29:03+00:00

Artificial neural networks (ANNs) are powerful nonparametric tools for estimating genomic breeding values (GEBVs) in genetic breeding. One significant advantage of ANNs is their ability to make predictions without requiring prior assumptions about data distribution or the relationship between genotype and phenotype. However, ANNs come with a high computational cost, and their predictions may be underestimated when including all molecular markers. This study proposes a two-step genomic prediction procedure using ANNs to address these challenges. Initially, molecular markers were selected either directly through Multivariate Adaptive Regression Splines (MARS) or indirectly based on their importance, identified through Boosting, considering the top 5, 20, and 50% of markers with the highest significance. Subsequently, the selected markers were employed for genomic prediction using ANNs. This approach was applied to two simulated traits: one with ten trait-controlling loci and heritability of 0.4 (Scenario SC1) and the other with 100 trait-controlling loci and a heritability of 0.2 (Scenario SC2). Comparisons were made between ANN predictions using marker selection and those without any marker selection. Reducing the number of markers proved to be an efficient strategy, resulting in improved accuracy, reduced mean squared error (MSE), and shorter adjustment times. The best ANN predictions were obtained with ten markers selected by MARS in SC1, and the top 5% most relevant markers selected using Boosting in SC2. As a result, in SC1, predictions using MARS achieved over a 31% increase in accuracy and a 90% reduction in MSE. In SC2, predictions using Boosting resulted in more than a 15% increase in accuracy and an 83% reduction in MSE. For both scenarios, computational time was up to ten times shorter with marker selection. Overall, the two-step prediction procedure emerged as an effective strategy for enhancing the computational and predictive performance of ANN models.

Genetic inheritance of ornamental components in pepper plants (Capsicum annuum L.)

2025-03-11T17:28:59+00:00

Limited information is available regarding the genetic inheritance of ornamental traits in peppers (Capsicum spp.), which is crucial for enhancing these plants for ornamental purposes in breeding programs. This study aimed to elucidate the genetic inheritance of ornamental traits in segregating populations of pepper plants (C. annuum L.) from distinct parents and to characterize them based on their flowering and fruiting cycles. The selected parents, UNI01 and UNI05, were sourced from the active germplasm bank of Universidade Estadual de Montes Claros, Janaúba, Minas Gerais State, Brazil. The experiment took place in a greenhouse, involving manual hybridization between UNI01 and UNI05 to obtain seeds of segregating populations, which included F1, RC1, RC2, F2, and F3 generations. Qualitative traits assessed included flower corolla color, immature fruit color, and shapes of longitudinal and transversal fruit sections. Quantitative traits encompassed mean flowering and fruiting days. We employed chi-square tests (χ²) to evaluate segregation patterns. The descriptor "corolla color" exhibited codominance, with a white corolla and purple borders linked to heterozygous genotypes. Dominant inheritance controlled the color of immature fruits, primarily purple. Genetic inheritance for transversal and longitudinal fruit shapes remained unexplained in the tested segregations. Parental and segregating generations displayed similar flowering and fruiting cycles. These results provide valuable insights for future breeding programs aimed at using this species for ornamental purposes.

Combination of mixed linear model approach with selection indices in kale breeding programs

2025-03-11T17:28:39+00:00

Utilizing selection indices is an effective strategy for the simultaneous evaluation of multiple traits in kale breeding programs. This approach allows for the selection of kale genotypes that exhibit enhanced productivity and adaptability by combining desirable attributes for the crop. In this study, we employed a mixed model approach in combination with various selection indices to estimate selection gains and recommend the most suitable index for kale breeding. The experiment was conducted at the Center of Development and Technology Transfer, Federal University of Lavras, Ijaci, MG. Thirty-four experimental genotypes were assessed in a randomized block design with three replicates, featuring four plants per plot. We evaluated several traits, including total leaf yield, number of leaves, average leaf mass, number of sprouts and chlorophyll content. Data analysis was performed at both the plot average level and the average quantity of the five harvests. Statistical analysis of mixed models confirmed the presence of genetic variability among kale genotypes. We examined the Smith and Hazel, Mulamba and Mock, Z-index, and FAI-BLUP indices. Smith and Hazel, Mulamba and Mock, as well as Z-index, were found unsuitable for leafy kale selection in breeding programs. The FAI-BLUP index demonstrated superior performance, aligning with the specific objectives of the kale breeding program and offering desirable gains. Therefore, we recommend the use of the FAI-BLUP index in kale breeding programs.

Low-density marker panels for genomic prediction in Coffea arabica L.

2025-03-11T17:28:30+00:00

Developing new cultivars, particularly in perennial species like Coffea arabica, can be a time-consuming process. Employing molecular markers in genome-wide selection (GWS) for predicting genetic values offers an alternative to accelerate this process. However, implementing GWS typically involves genotyping many markers for both training and candidate individuals, which can increase the total genotyping cost for the breeding program. Therefore, this study aimed to assess the feasibility of using low-density marker panels to predict the genetic merit of C. arabica for a range of desirable agronomic traits. For this purpose, GWS analyses were performed using the G-BLUP method with panels of varying marker densities, selected based on marker effect magnitude. The results indicate that employing lower-density panels might be advantageous for this species' improvement. Models based on these panels yielded accurate predictions for various traits and demonstrated high agreement in terms of selected individuals compared to more complex models.

Adaptability and stability of corn genotypes for baby corn production via GGE biplot and REML

2025-04-22T17:44:15+00:00

Owing to the interaction between genotype and environment (G × E), selecting and developing high-yielding varieties with strong phenotypic adaptability and stability is paramount. Therefore, this study aimed to determine the efficiency of selection of corn genotypes for baby corn production based on productivity, adaptability, and stability. Eleven corn genotypes were evaluated in six municipalities in the state of Espírito Santo, Brazil in 2019. Superior genotypes were selected using the harmonic mean of the relative performance of the predicted genetic values (HMRPGV) and graphical analysis using the genotype main effect plus G × E (GGE) interaction biplot. Genotypes AG 1051 and BR 106 exhibited the best performance across environments. The HMRPGV method and ideotypes obtained through graphic analysis proved effective in selecting genotypes with high productive potential, responsiveness to environmental changes, and highly predictable behavior in the face of environmental stimuli.

Implications of plant survival in the quality of experiments to evaluate progenies of the genus Corymbia

2025-04-22T17:44:05+00:00

The evaluation of Corymbia maculata and C. torelliana progenies has received much attention in Brazil in the last decade. For the process to be efficient, experiments must be as precise as possible. Factors that affect accuracy include plant survival (PS) and assessment age. The objectives of this study were to determine whether there are differences in progeny PS among evaluation sites and ages, whether dominated plants affect precision estimates, and how potential damage caused by differences in PS can be mitigated. Data from the evaluation of half-sib progenies of C. maculata at three sites and C. torelliana at four sites were used. The experiments were implemented in an alpha-lattice design with 40 repetitions and a single-tree plot (STP). Diameter at breast height (DBH) and PS data were obtained at three and six years of age. All plants that presented DBH with a deviation below the mean (dominated plants) were not considered in the survival estimates. Although there was a difference in plant survival between progenies and experiments, none of the strategies used to mitigate damage due to differences in PS significantly changed the classification of progenies or the magnitude of the accuracy. There was a high association between the estimates obtained at three and six years of age, indicating that for species of the genus Corymbia, early selection is viable.

Physiological and nutritional parameters of drought resistance in coffee seedlings genotypes

2025-04-22T17:44:03+00:00

Drought is an environmental condition that compromises the development of coffee plants. New coffee genotypes that are resistant to drought must be selected quickly and practically. The objectives of this study were to evaluate the resistance of five genotypes of Coffea arabica, including three new genotypes with introgression of genes from Coffea racemosa (H0113-40-26-1, H0113-40-26-19, and H0113-40-26-10), to water restriction and relate the intensity of plant wilting with physiological responses and nutrient accumulation. The experiment was conducted using 45 coffee seedlings obtained from seeds with six pairs of leaves cultivated in tubes. Some seedlings were subjected to two water restriction periods, whereas the remainder were kept under irrigation. The photosynthesis rate, transpiration rate, and wilting intensity were evaluated after each restriction period. Nutrient content was also evaluated after two periods of water restriction. The evaluation of wilting intensity corroborated the physiological parameters. There was a reduction in photosynthesis and transpiration rates under water restriction and nutrient accumulation in coffee seedlings H0113-40-26-1, H0113-40-26-19, and H0113-40-26-10 increased under these conditions. C. arabica genotypes carrying the genes of C. racemosa presented good drought resistance, with H0113-40-26-10 being the most resistant and showing the lowest wilt intensity.

Selection of differentiated maturity genotypes of Coffea canephora

2025-04-22T17:43:55+00:00

The aim of this study was to select Coffea canephora genotypes from the seminal propagation variety ‘ES8152’ with different harvest times. The experiment was conducted using a Federer augmented block design with three repetitions, evaluating 175 genotypes and four clonal witnesses in two harvests (2022 and 2023), and 20 morphoagronomic characteristics were evaluated. The data were analyzed using the REML/BLUP methodology with the Selegen software, where the variance components and genetic values were estimated. The selection was performed using the Mulamba-Rank index. The bottom sieve (BS) and top sieve (TS) characteristics had high heritability (0.5779 and 0.6694, respectively) and accuracy (0.7602 and 0.8182, respectively). TS also showed high repeatability (0.6827). The genotypic effects were significant at 1% level for days for fruit ripening, fruit size, vegetative vigor, yield per plant, TS, and BS; at 5% level for general scale; and at 10% level for incidence of rust, degree of inclination, and percentage of fruit float. It was possible to distinguish 20 superior genotypes in terms of maturation, among which the selection gains for the genotypic clusters were 46.14, 45.92 and 41.56% for indefinite, early, and late maturation, respectively, by applying a selection intensity of 11.43%. Genotypes 25, 26, 73, 93, and 100 could be used for early maturing varieties, whereas genotypes 155 and 189 could be used for late-maturing varieties. The most promising genotypes for composing a variety, regardless of the maturation period, were 20, 39, 90, 112, and 190, as these were among the five best genotypes ranked in the three selection processes, demonstrating that they added superior desired morphoagronomic characteristics. It is concluded that there is genetic variability among the 175 genotypes evaluated, as well as significant genetic effects to be explored in the pool gene of individuals originating from the 'ES8152' variety.

Impact of environmental covariates on genotype-environment interactions in a semi-arid region of Rio Grande do Norte State, Brazil

2025-04-22T17:43:52+00:00

Limited knowledge exists on the impact of environmental covariates on the genotype-by-environment (G × E) interaction in melon cultivated under semi-arid conditions. This study assessed the influence of environmental covariables on G × E interactions and identified melon genotypes demonstrating adaptability and stability. Thirteen yellow melon hybrids were evaluated in randomized blocks with three replications across four municipalities in Rio Grande do Norte State during two distinct seasons. Traits investigated included the number of fruits per plant and soluble solids. Factor regression and principal component analysis were employed to quantify the influence of maximum and minimum temperature, relative humidity, and radiation on the G × E interactions. The Harmonic Mean of Relative Performance of the Genotypic Values method identified adapted and stable genotypes. The covariate-biplot model established relationships between crucial environmental covariables and their impact on the number of fruits per plant and soluble solids. Minimum temperature, relative humidity, and solar radiation significantly contributed to the G × E interactions in melon. Hybrids exhibited distinct sensitivities to environmental covariates, with HA-08 emerging as the most stable and adapted hybrid for both the number of fruits per plant and soluble solids.

Multivariate approach for identifying wheat Triticum aestivum L. tolerant to heat and drought stress

2025-04-22T17:43:50+00:00

Breeding wheat for production in the Brazilian Cerrado region should aim at developing productive genotypes adapted to heat and drought conditions; therefore, this study evaluated the tolerance of wheat cultivars to heat/thermal and drought stress. To meet this objective, 30 wheat cultivars were cultivated in 3 greenhouse environments, namely control, drought, and heat, applying stress from the booting stage to the end of anthesis. The following parameters were evaluated: cycle, plant height, spike number per plant, spike length, spike weight, spikelet number per spike, percentage of fertile spikelets, number of grains per spike, and grain weight per spike. Principal component analysis and cluster analysis were performed by the Ward and “K-means” methods. Principal component analysis showed that the correlations between the productivity traits and the principal components were more affected by drought than by the control and heat environments. The cluster analyses formed five clusters for the control and heat environments and seven clusters for the drought environment. Grain productivity was highlighted in the heat environment for ‘BRS 210’, ‘BR18 Terena’, ‘IPR Catuara TM’, ‘CD 154’, ‘BR 220’, ‘MGS Aliança’, ‘IAC 350’, ‘IAC Tucunaré’, ‘BR 24’, ‘IAC 5 Maringá’, ‘UFVT1 Pioneiro’, and ‘CD 151 4’ with a positive relationship in principal component analysis. Considering spikelet number per spike in the drought environment, cultivars ‘BRS 208’, ‘IAC 350’, ‘Supera’, ‘BRS 210’, ‘IPR 85’, ‘IPR Catuara TM’, ‘Anahuac 73’, ‘BR 24’, ‘IAC 5 Maringá’, and ‘UFVT1 Pioneiro’ were highlighted. In the drought environment, most of the productivity-related traits exhibited components with negative relationships among cultivars and the evaluated traits, confirming their response to the induced stress.

Interploid hybrids in the ‘brizantha’ complex of Urochloa P. Beauv.: identification, genome size, cytogenetic characterization and perspectives

2025-07-08T19:53:15+00:00

Crossing between sexual artificial tetraploids of Urochloa ruziziensis and apomictic polyploids of Urochloa decumbens, and Urochloa brizantha is a breeding strategy. Crosses are carried out without prior emasculation of the plants; therefore, confirmation of hybridization and identification of pollen donors require reliable techniques such as microsatellite markers. Information on the reproductive mode, chromosome number, and genome size is also important. The aims of this study were (i) to identify the male parents and mode of reproduction of the three hybrids using molecular markers, (ii) to define the chromosome number and ribosomal DNA (rDNA) sites using fluorescent in situ hybridization (FISH), and (iii) to estimate genome size using flow cytometry. The simple sequence repeats (SSR) markers identified U. brizantha cv. Marandu, U. brizantha genotype 2 and U. brizantha cv. Xaraés as the male parents of hybrids 1F/21, 7F/153, and 10F/v5, respectively. The 1F/21 hybrid was aneuploid (2n = 36+1, 2C = 3.61 pg), whereas the 7F/153 (2n = 40, 2C = 3.79 pg) and 10F/v5 (2n = 41, 2C = 3.88 pg) hybrids resulted from interploid crosses involving U. brizantha (2n = 5x = 45). The p779/p780 apospory marker was not amplified in the hybrids, indicating sexual reproduction. The number of rDNA sites shows a dynamic behavior and inheritance of these sequences, while the position of the sites on the chromosomes is conserved within the ‘brizantha’ complex. Identifying interploid hybrids provides new perspectives for Urochloa breeding, with the possibility of exploring the genetic variability of other apomictic polyploids. These results are promising in terms of inferences and highlight the need for further studies on interploid hybridization in Urochloa.

Use of cytogenetic techniques and flow cytometry to characterize the yacon genome

2025-07-08T19:53:10+00:00

Yacon (Smallanthus sonchifolius), a tuberous root native to the Andean region, is cultivated in various countries and is valued as a functional and medicinal food due to its nutraceutical properties. These properties include probiotic, antidiabetic, antioxidant, and antimicrobial effects, which contribute to its beneficial impact on human health. Despite this, the genetic diversity of yacon, which significantly influences trait expression and phenotypes, remains poorly explored. To date, only the number of chromosomes in the karyotype has been reported. This study, therefore, aimed to measure the nuclear genome size, determine the chromosome number, and characterize the karyotype of different yacon genotypes. For the first time, this research presents the karyogram and calculates the 2C nuclear value of yacon genotypes cultivated in a tropical environment outside the Andean region. This analysis is particularly significant as genetic material can be influenced and altered by environmental conditions. Our findings aim to identify such potential variations. The karyotype was characterized by 29 pairs of chromosomes: 13 submetacentric (1–5, 7–12, 14, 20) and 16 metacentric pairs (6, 13, 15–19, 21–29), with sizes ranging from 3.64 to 1.67 μm and secondary constriction in chromosome pair 21. Moreover, the karyotype presented a chromosome number of 2n = 58, contrasting with individuals of yacon cultivated in tropical environments, which presented a chromosome number of 2n = 32. The average 2C DNA content found was 2C = 6.39 pg, corroborating previous reports that presented relative variations from 2C = 5.82 to 6.12 pg. The observed genome 1C = 3,124.710 Mbp was considered small. Our methodology successfully obtained prometaphase and metaphase chromosomes, free of cytoplasmic traits and without overlaps. This study enriches the fundamental genetic knowledge of yacon, contributing to its conservation, evolution, and diversification, and affecting its agricultural potential beyond the Andean regions.

Estimation of inbreeding depression in Psidium guajava through seed attributes using S0, S1, and S2 families

2025-07-08T19:53:18+00:00

Inbreeding depression, resulting from self-pollination or mating between closely related plants, primarily impacts quantitative traits. This study aimed to assess inbreeding depression in guava seeds from two generations of self-pollination (S₁ and S₂) relative to open-pollinated (S₀) seeds, focusing on seed physical and physiological attributes. Physical seed quality was assessed by determining the weight of 1,000 seeds and analyzing seed images using the GroundEye^® instrument. Physiological quality was evaluated through germination and accelerated aging tests, along with the emergence speed index, root length, and shoot length. The results revealed no inbreeding depression in the first selfing generation. However, mild levels of inbreeding depression were observed across all traits in the second selfing generation. This study underscores the importance of understanding inbreeding depression dynamics in guava seeds, particularly in subsequent generations of self-pollination, for effective breeding and seed quality management.

Marker pre-selection as a strategy to enhance genomic prediction with machine learning: Exploring the influence of trait-specific genomic structures

2025-09-05T11:24:32+00:00

This study focused on incorporating dimensionality reduction based on marker significance to better harness the potential of machine learning for genomic prediction in different trait-genomic structures. The aim was to show that outcomes achieved with reduced data would improve predictive accuracy ( ) and precision (root-mean-square error: RMSE) while reducing computational time. Distinct subsets of markers, in simulated data, were chosen by prioritizing importance via the Bagging technique. Predictive modelling was subsequently conducted using both Bagging and the diverse architectures of a Multilayer Perceptron (MLP) neural network. This study was carried out with six traits of an F₂ simulated population (derived from contrasting homozygotes) with 1,000 individuals. Three traits had three different heritabilities (0.4, 0.6, and 0.8) and were controlled by a set of 40 quantitative trait loci (QTLs). Additionally, four QTLs with more pronounced heritability effects (set at unity) were introduced in three other traits while preserving the same genetic control structure as the earlier traits. In our investigation, as the number of markers increased, both techniques gradually increased training time; however, the time needed for computation notably extended beyond the threshold of 100 markers for Bagging. In comparison to the MLP model, the Bagging model generally obtained better accuracy (higher ) and precision (lower RMSE) values regardless of heritability and added QTLs. Most importantly, results highlight that for traits subject to robust genetic control of additional QTLs, MLP networks experienced a decline in prediction performance from a few markers (~10). In contrast, Bagging kept constant or subtly improved predication performance. Finally, the dimensionality reduction procedure effectively improves genomic prediction, and Bagging captures complex genetic control structures for prediction better than MLP networks.

Enhancing fruit quality and stress resilience: Genetic advancements in dwarf tomato populations

2025-09-05T11:25:16+00:00

This study investigated the enhancement of fruit-related traits in dwarf tomato populations through advanced hybridisation strategies, employing UFU MC TOM1 as the donor parent. This experiment was conducted at the Federal University of Uberlândia’s experimental station over 3 production cycles from 2019 to 2021. Crossbreeding and backcrossing were performed using UFU-57 as the recurrent parent and UFU MC TOM1 as the donor parent, and dwarf plants were selected in the BC1F2 and BC2F2 generations. This research focused on improving key fruit quality attributes, including size, acidity, and phytonutrient levels, such as β-carotene and lycopene. Notable improvements were observed, particularly in the second backcrossing generation, which produced salad-type fruit with enhanced traits. Promising populations, including UFU × DTOM 8#2-3, UFU × DTOM 22#1-17, and UFU × DTOM 4#4-14, demonstrated significant potential for further lineage development and hybrid breeding programs. Metabolomic analysis identified increased levels of glycine, myo-inositol, acetamide, and dodecanoic acid in the dwarf salad-type tomato line, which were likely associated with improved stress resilience, enhancing its potential for breeding robust cultivars. These results provide a crucial understanding of the genetic mechanisms underlying fruit quality improvement and stress resistance in dwarf tomato. These findings highlight the potential for developing superior cultivars that combine improved nutritional quality with enhanced resilience to biotic and abiotic stressors, thereby contributing to sustainable agricultural practices and food security.

Hydrogel polymer as a sustainable input for mitigating nutrient leaching and promoting plant growth in sugarcane crops

2025-03-11T17:29:17+00:00

Nutrient leaching is a common issue in sandy soils. The use of hydrogel polymers can mitigate this problem by enhancing soil water retention. This study aims to assess the effect of hydrogel polymer application on nutrient leaching in sugarcane-cultivated soil and its impact on plant growth over a 196-day cycle. Parameters examined include soil water retention (%), nutrient leaching (N, P, K, Ca, Mg, and S) analyzed through the water collected after natural drainage, as well as various plant growth parameters such as stem height and diameter, and fresh and dry stem and leaf mass. The highest soil water retention was observed in treatments with 1.5 and 2.0 g kg^-1 of hydrogel polymer. Regarding nutrient leaching, the treatments with 1.5 and 2.0 g kg^-1 of hydrogel polymer exhibited the lowest values, resulting in reductions of over 85% for all accumulated nutrients leached by the end of the crop cycle. The application of hydrogel, especially at higher doses, also enhanced sugarcane growth, notably increasing fresh stem mass. These results suggest that hydrogel polymers could serve as a sustainable solution for controlling nutrient leaching in sugarcane cultivation, contributing to the sustainable development of agriculture and environmental preservation.

Evaluating the feasibility of late nodulation in common beans

2025-03-11T17:29:07+00:00

The nodulation of common beans occurs continuously until the flowering stage, followed by nodule senescence. However, reports have indicated the potential for late nodulation in this species, contributing to increased grain production. This study aimed to evaluate the occurrence of late nodulation in common beans and its contribution to plant growth. Experiments were carried out by testing two inoculation strategies: rhizobial inoculation (1) in different sections of the root system and (2) at different phenological stages. Plants were harvested at flowering and the beginning of pod filling. When the first strategy was applied, both inoculation on the seeds and throughout the pot volume resulted in greater nodulation compared to the uninoculated control. However, shoot biomass accumulation remained unaffected. When the second strategy was applied, supplementary inoculation at different stages did not improve nodulation or plant growth compared to seed inoculation. We conclude that neither method promoted effective late nodulation of common beans and that seed inoculation was sufficient to promote good vegetative development of common beans.

Crop-livestock integration systems mitigate soil compaction and increase soybean yield

2025-03-11T17:28:48+00:00

The use of integrated agricultural production systems has been expanded due to the multiple functions they perform. Although soil structural studies have elucidated the relationship of these systems with plant development, adjustments are needed to incorporate the diversity of management systems employed. Thus, the hypothesis of this study was that integrated cropping systems mitigate soil structural degradation and increase the agronomic performance of crops. The objectives of this study were to evaluate the biological soil loosening potential containing paiaguás grass and the effectiveness of integrated systems in promoting the agronomic performance of soybean plants and to model the least limiting water range (LLWR) considering the adopted management regimes. An experiment was performed based on a randomized block and split-plot design. In the plots, the traffic intensity (0, 2, 10, and 30 passes of an agricultural tractor. In the subplots, soybean cultivation was performed under the three management systems (simple: monoculture grains; integrated: intercropping between grass and grains; and pasture in monoculture). The following soil physical quality indicators were determined: bulk density (Bd) and LLWR; these indicators are related to phenological development attributes and soybean productivity. The integrated agricultural production systems promoted biological soil loosening and improved soybean yield. The use of Paiaguás grass in monoculture enhanced edaphic benefits and enabled greater grain production compared to grain monocropping. The least limiting water range was an efficient parameter for modeling the physical behavior of the soil, and the application of the LLWR was improved by considering penetration resistance reference values specific to each management system. Our results highlight the soundness of using the LLWR in evaluating the response of soybean to physical changes in soil due to compaction, and the reference values for penetration resistance contribute to greater accuracy in the LLWR and the physical diagnosis of soil properties.

Parameterization of the APSIM-Oats model for simulating the growth of black oat cultivated for forage purposes under cut-and-carry management

2025-03-11T17:28:45+00:00

Studies on modeling the growth of annual crops are typically conducted for economically significant crops like soybeans, corn, and wheat. Conversely, there has been limited exploration of annual forage crops, despite their substantial importance, as they can help address forage supply shortages during periods of low production for perennial tropical forages. This study aimed to parameterize the APSIM-Oats model for simulating the growth of black oats (Avena strigosa Schreb cv. IAPAR 61 Ibiporã) cultivated for forage purposes and managed under a cut-and-carry system. Two experiments were conducted in 2018 and 2019 in Piracicaba, São Paulo State, Brazil, encompassing both irrigated and non-irrigated plots. Various productive, biometric, and soil moisture variables were monitored throughout the crop cycles. Parameters were manually calibrated through a trial-and-error process until the estimates closely matched the observed data. Model evaluation involved comparing observed and simulated data using statistical indices. The most favorable results were obtained for live biomass, leaf mass, and stem mass (with modeling efficiency exceeding 0.55 in the rainfed system and surpassing 0.34 for the irrigated system). Estimates of soil water content exhibited better accuracy for shallower soil layers (0 to 0.30 m). The calibration of the APSIM-Oats model for black oats yielded satisfactory estimates for live biomass under rainfed conditions. The simulations in this study represent an initial step in modeling the growth of black oats.

Optimizing nitrogen fertilization with Azospirillum brasilense and biostimulants for green corn

2025-03-11T17:28:42+00:00

In tropical and subtropical regions, nitrogen (N) is often limited and significantly impacts corn production costs. In this context, bio-inputs have been used to reduce N and water supplied to plants. This study assesses the impact of varying N levels, Azospirillum brasilense seed inoculation, and biostimulant use on the agronomic performance of summer-grown green corn (Zea mays L.) across three growing seasons (2017/2018, 2018/2019, and 2019/2020). Five N-fertilizer levels (0, 30, 60, 90, and 120 kg N ha^-1), two A. brasilense seed inoculation levels (0 and 100 mL ha^-1), and two biostimulant doses (0.0 and 1.0 L ha^-1) were evaluated in a completely randomized block design, arranged in a 5 x 2 x 2 factorial scheme, with four replications. Results showed that A. brasilense seed treatment did not increase ear yield or kernel protein content (PROT) and reduced PROT when combined with the two highest N levels. The application of biostimulant increased ear weight by 5.08% in the 2018/2019 growing season, leading to an increase in PROT. However, the use of inoculant and biostimulant did not reduce the amount of N-fertilizer applied to green corn plants.

Optimizing Merremia aegyptia and Calotropis procera biomass application rates in kale cultivation under semi-arid conditions

2025-03-11T17:28:34+00:00

This study aimed to optimize both agronomically and economically leaf green mass productivity of kale and its agronomic components when fertilized with equivalent biomass amounts of the hairy woodrose (Merremia aegyptia L.) and roostertree (Calotropis procera Ait.) spontaneous species from the Caatinga biome in two cropping seasons. The experimental design was in randomized blocks with five treatments and five replications. The treatments consisted of equivalent biomass amounts of hairy woodrose and roostertree at doses of 16, 29, 42, 55, and 68 ton ha^-1, on a dry basis. In each experiment, a treatment without fertilization (control) and a treatment with chemical fertilization were used. The maximum optimized physical efficiencies of the kale commercial leaf productivity and number of leaf packets per square meter were 16.92 ton ha^-1 and 6.97, respectively, when the amounts of the green manure biomass of 56.41 and 48.63 ton ha^-1 were incorporated into the soil. The optimized maximum net income of 47,841.44 BRL ha^-1 and rate of return of 2.47 reals for each real invested were obtained when the amounts of the green manure biomass were 53.26 and 64.31 ton ha^-1 added to the soil. The use of M. aegyptia and C. procera biomass as green manure is a viable technology for kale producers in monocropping in a semi-arid environment.

Postharvest quality of atemoya at various stages of ripeness grown in semi-arid conditions

2025-04-22T17:44:13+00:00

Atemoya has a short post-harvest shelf life due to its high metabolic activity. Limited information is available on the optimal harvest time for atemoya grown in semi-arid conditions. This study aimed to evaluate the quality of atemoya fruits at various maturity stages under semi-arid conditions. Fruit was harvested from a commercial orchard and the experiment was conducted in a completely randomized design (CRD) with a 3x5 factorial scheme. This included three maturation stages (100, 105, and 110 days after pollination - DAP) and five refrigerated storage periods (0, 3, 6, 9, and 12 days), with four repetitions. The fruits were stored at 15 ± 2°C and 74 ± 2% RH and subjected to physical, chemical, and biochemical evaluations. Throughout storage, there was a significant fresh mass loss of 13.83, 11.99, and 11.92% for fruits harvested at 100, 105, and 110 DAP, respectively. Firmness and starch content also decreased as starch was converted into sugars. Across all maturation stages, the shelf life was limited to nine days due to compromised appearance, primarily cracks and peel darkening. Fruits harvested at 105 and 110 DAP exhibited better quality at the end of storage, including improved appearance, greater mass, lower weight loss, and higher soluble solids and vitamin C content. The results suggest that atemoya fruits can be harvested between 105 and 110 DAP under semi-arid conditions. Thus, atemoya shows commercial potential for production in the semi-arid region.

Early growth of pecan cultivars under organic production

2025-04-22T17:44:11+00:00

Organic pecan production may offer not only a chance to increase economic returns-due to its increased product value-but also to avoid pesticide applications. This contributes to the growth of residue-free food and protects the environment. However, there is limited data on the performance of pecan cultivars in ecologically-based systems, especially regarding growth and susceptibility to scab (Venturia effusa) during the early developmental stages of orchards. This study aimed to evaluate the early growth of pecan cultivars in an organic production system in Pelotas, Rio Grande do Sul State, Brazil. The cultivars evaluated were Melhorada, Imperial, Success, Importada, Barton, Farley, Shawnee, Chickasaw, Desirable, Cape Fear, Choctaw, Elliot, Mahan, Sioux, Stuart, and Sumner. Their phenology, vegetative growth, and susceptibility to scab were assessed from 2018 to 2022. Sumner, Stuart, Desirable, Success, and Imperial exhibited the highest early growth under experimental conditions. Chickasaw, Desirable, Sioux, and Cape Fear were the most precocious cultivars in terms of bud break, while Barton, Farley, Stuart, and Sumner were the latest. In terms of scab susceptibility, Cape Fear, Chickasaw, Choctaw, Mahan, and Sioux were the most susceptible cultivars, whereas Barton, Elliot, and Stuart were the least susceptible under experimental conditions. In the early stages, Barton, Elliot, Success, Stuart, Sumner, Desirable, and Imperial were the standout cultivars in the organic production system.

Postharvest indices of radish and coriander in intercropped systems under green manure and population densities

2025-04-22T18:15:35+00:00

The objective of this work was to estimate the postharvest quality indices of radish and coriander products in an intercropping system based on different equitable amounts of hairy woodrose (Merremia aegyptia L.) and roostertree (Calotropis procera (Ait.) R. Br) biomass in two cropping seasons in a semi-arid environment. The experiment was set up in completely randomized blocks with treatments arranged in a 4 × 4 factorial scheme, with 4 replications. The first factor consisted of equitable amounts of biomass mixtures of hairy woodrose and roostertree at doses of 20, 35, 50, and 65 t ha⁻¹ on a dry basis, and the second factor of coriander population densities of 400, 600, 800, and 1,000 thousand plants ha⁻¹, intercropped with 500 thousand plants ha⁻¹ of radish. The characteristics evaluated in both crops were pH, soluble solids (SS), titratable acidity (TA), SS/TA ratio, total soluble sugars (TSS) and vitamin C content (vitamin C), and the chlorophyll a and b, total chlorophyll, and carotenoid contents were also evaluated in coriander. Fertilization with green manures M. aegyptia and C. procera increased the radish postharvest indices, SS, TA, and TSS, reaching maximum values in the biomass amounts of 39.35, 20, and 40.65 t ha⁻¹, respectively, and improved the quality of radish roots grown in intercropping with coriander. This practice with these green fertilizers promoted improvements in the quality of coriander pigments after intercropping with radish, which was expressed as increases in chlorophyll a and b, total chlorophyll, and carotenoid contents in the biomass amounts of 43, 53, 43, and 65 t ha⁻¹, respectively.

Multivariate relationships in strawberry cultivated with native communities of arbuscular mycorrhizal fungi

2025-04-22T17:43:57+00:00

The mechanisms underlying the interactions between native mycorrhizal fungal communities and strawberry plants remain unclear. However, the identification of specific associations among variables and their influence on the total experimental variability when using inoculants based on arbuscular mycorrhizal fungi should enable the identification of the most relevant ones. Herein, our objective was to identify and characterize variables related to each other and to the total experimental variability among strawberry plants inoculated with native mycorrhizal communities. Experimental treatments included an uninoculated control and eight multi-specific inoculants from cultivated soils and native forests from reference strawberry-cultivation sites (Bom Princípio, Flores da Cunha, Ipê, and São José of Hortêncio) in Rio Grande do Sul State, Brazil. Morphological, productivity, and quality traits were evaluated. Inoculants obtained from agricultural ecosystems of Bom Princípio and Ipê did not influence the horticultural performance of strawberries, while those from Flores da Cunha largely explained total experimental variability, and therefore, should be considered when selecting the location to obtain inoculants for use on strawberry plants. Number of fruits, fruit flavor, chlorophyll a, and total chlorophyll contents, and, most importantly, root variables, should be included for experimental analysis of ‘Albion’ strawberry responses to multi-specific mycorrhizal inoculants from different locations.

High-density pecan trees subjected to hedge and central pruning and thinning in southern Brazil

2025-04-22T17:43:48+00:00

Several high-density pecan orchards have exhibited unsatisfactory growth and production due to excessive shading. This study aimed to investigate hedge and central pruning and tree thinning as alternative solutions to increase the vegetative growth and production of pecan trees in high-density orchards. The experiment was conducted in Santa Rosa, Rio Grande do Sul State, Brazil, using a randomized block design with three replicates, each consisting of five trees. Treatments included: i) control (no treatment), ii) hedge pruning, iii) central pruning, and iv) tree thinning (tree removal). We evaluated vegetative growth, the number of dry branches, and aspects related to production and production efficiency. Tree thinning resulted in increased transverse width, canopy volume, and the number of basal branches, along with a decrease in dry branches per tree. Production was higher in trees subjected to thinning (42.89%), followed by central pruning (39.80%) and hedge pruning (37.03%), compared to the control. The average yield was higher than the control after both pruning methods; hedge and central pruning increased yield by 37.20 and 39.85%, respectively. However, tree thinning decreased yield by 10.80%. Trees subjected to hedge pruning achieved higher production efficiency relative to canopy volume than the control, while, concerning trunk cross-sectional area, tree thinning was more efficient than the control. Tree thinning increases vegetative growth, production, and production efficiency, while hedge pruning and central pruning lead to higher yields.

High-density planting effects on maxixe production

2025-07-08T19:53:29+00:00

Maxixe is a vegetable with high nutritional value, yet there is limited information on crop management practices, particularly regarding row and plant spacing. This study aimed to evaluate maxixe production under high planting densities in two locations, Montes Claros and Mocambinho, Minas Gerais State, Brazil. The experiment was designed as a 2 x 2 x 4 factorial scheme, with two locations, four plant numbers per hole, and four hole densities, using the cultivar Maxixe do Norte. A randomized block design with four replications was employed. The variables analyzed included the number of fruits per plant and per hectare, pericarp thickness, fresh and dry fruit mass, and overall productivity. Data were subjected to multiple regression analysis, and curve comparisons were made using the model identity test. No significant difference was observed in fruit yield between the two locations; the highest yield recorded was 56,489.63 kg ha^-1 at the highest planting densities. Increased planting density resulted in higher yields in weight and number of fruits per area, but fewer fruits per plant and reduced fresh and dry fruit mass at higher densities. Therefore, considering production per area and plant, an intermediate planting density is most appropriate, as it enhances yield without compromising fruit quality. In short, the recommended density for optimal fruit production is 33,000 holes per hectare, with three plants per hole.

Using aerial images to estimate production in forage cactus cultivars

2025-07-08T19:53:23+00:00

Predicting forage palm yield is a valuable tool for producers, aiding in harvest planning and crop management. This study aimed to evaluate the efficiency of using aerial images from a low-cost setup to estimate cladode production in four forage cactus cultivars. The experiment followed a randomized block design in a 4 x 4 factorial arrangement, with four replications. The first factor included the four cultivars: Giant, Miúda, Elephant Ear, and IPA Sertânia. The second factor involved four cladode harvest management strategies: (1) harvest at nine months, preserving the mother cladode; (2) harvest at nine months, preserving the mother and primary cladode; (3) harvest at 15 months, preserving the mother and primary cladode; and (4) harvest at 21 months, preserving the mother cladode. Before each harvest, aerial images were captured for each plot. The number of cladodes, fresh matter, and dry matter yield per harvest were calculated. Image processing was performed using the ExpImage package in the R software. The efficiency of predicting cactus yield using aerial images obtained with low-cost equipment was confirmed. Individually adjusted models for each cultivar provided greater precision in estimates. However, a single model for all four cultivars achieved a coefficient of determination greater than 77% for estimating fresh matter yield.

Yield of creole corn under the residual effect of leguminous plants in the northeastern semi-arid region

2025-07-08T19:53:02+00:00

Agroecological production systems require profitable edaphic management strategies; therefore, the adoption of leguminous plants has become a strategy for improving nutrient cycling and straw input in the soil for subsequent crops. The objective of this study was to evaluate dry matter production and nutrient levels in leguminous plants grown alone and their effects on maize grown in succession in an agroecological production system. We conducted field experiments in two harvests under a randomized block design with eight treatments and three replicates. The treatments used were mulch, Mucuna pruriens, Mucuna pruriens (L.) DC., Dolichos lablab, Cajanus cajan, control (soil without vegetation cover), Crotalaria juncea, and Canavalia ensiformis. At the end of flowering, approximately 67 days after sowing (DAS), plants were collected and deposited in the soil as cover and fertilizer. The production of dry matter and nutritional content (nitrogen (N), phosphorus (P), and potassium (K)) in the agricultural fertilizers were analyzed, followed by the sowing of corn after this deposition as a form of residual fertilization. C. juncea produced the maximum amount of straw dry matter of 15,000 kg ha^-1, with a high N content (32.2 g kg^-1) but low K content (0.3 g kg^-1). Black velvet showed high K content (3.4 g kg^-1), and M. pruriens (MPL) showed high P content (3.0 g kg^-1). Production parameters were determined on a large scale using C. juncea and C. ensiformis, with average values of 3,380 kg ha^-1. The incorporation of green leguminous manures (sun hemp and jack bean) resulted in better yields in maize production components (ear length, ear diameter, number of rows, mass of 100 grains, and productivity) owing to the high accumulation of aerial phytomass and high N uptake under local conditions.

Uniconazole in seed treatment modifies the early growth of maize

2025-07-08T19:53:00+00:00

In Brazil, corn crops are frequently affected by extreme temperatures and wide variation in water and radiation availability. These factors, coupled with the increasing incidence of pests and diseases and different management practices, limit crop yield. Alternatives that provide increased resilience in plants are of paramount importance, such as the use of growth regulators. This study aimed to investigate the effect of uniconazole (UCZ) applied to corn seeds on the germination, and growth of the shoot and root system at the initial stage of plant development. The experiments consisted of evaluating UCZ doses (0, 50, 100, 150, and 200 mg kg⁻¹ seed) applied to seeds on the viability and vigor of seedlings. Moreover, the effect of UCZ doses on growth and biomass accumulation, root system morphology, contents of chloroplast pigments and nutrients, and leaf reflectance in plants grown up to the V4 stage was also evaluated. UCZ treatment on seeds promoted a delay in the germination process with increasing doses, also leading to a reduction in the shoot size and biomass without an influence on the root system. Vigor assessment showed that increasing UCZ doses applied to the seeds promoted reduction in the shoot size and biomass without changing germination. Plants grown in a greenhouse had inhibition of the initial shoot growth, with the height becoming uniform over time, regardless of the UCZ dose. Root data revealed that increasing the UCZ dose promoted an increase in root length and area with a reduction in diameter. Changes in chlorophyll a and b contents were also detected, in addition to the light absorption capacity depending on the UCZ dose. Seed treatment with UCZ at doses of 100 and 150 mg kg⁻¹ seeds increased Fe, Si, K, Co, Ca, Mg, S, and Na contents in young plants. Lately, UCZ benefited the growth and development of young corn plants.

Leaf gas exchange and mineral nutrition of Clitoria Ternatea intercropped with forage cactus under supplemental brackish water irrigation

2025-07-08T19:52:58+00:00

Supplemental irrigation using moderately saline water and intercropping are effective strategies for mitigating the adverse effects of water stress on leaf physiology, particularly during dry periods. This study aimed to assess the impact of supplemental irrigation with brackish water (3.0 dS m^-1) on leaf gas exchange and mineral concentrations in butterfly pea (Clitoria ternatea L.) when intercropped with forage cactus (Opuntia stricta). Conducted under a semi-arid climate in 2022 and 2023, the experimental design was a randomized block in split plots, with four replicates. The main plots consisted of two water scenarios: no irrigation and supplemental irrigation. The subplots comprised three cropping systems: butterfly pea in monoculture (B) (1.0 x 0.1 m), forage cactus (2.0 x 0.1 m) intercropped with a line of butterfly pea (P+1B), and forage cactus (3.0 x 0.1 m) intercropped with two lines of butterfly pea (P+2B). Supplemental irrigation was applied to the butterfly pea from February to June during dry spells and fully during the onset of the dry season (July and August). This irrigation approach alleviated water stress impacts on stomatal conductance, net photosynthesis rate, transpiration rate, and internal CO₂ concentration, and enhanced the levels of K⁺, Ca²⁺, Cl^-, and Na⁺. Additionally, the P+2B system, when supplemented, led to increased accumulation of N and P. Intercropping improved leaf gas exchange and reduced Cl^- concentration in C. ternatea, thus benefiting its agronomic performance.

Impact of gibberellic acid on seedling growth and enzymatic activity in bean cultivars with contrasting seed vigor

2025-07-08T19:52:55+00:00

Soaking seeds in gibberellin acid (GA) can reveal mechanisms controlling seed vigor. GA acts early in germination, stimulating the synthesis of hydrolytic enzymes that break down starch to provide the energy needed for radicle protrusion. This study investigated the effects of gibberellic acid (GA₃) on physiology, biochemistry, and molecular components in bean cultivars with different vigor levels. Two cultivars (BAF44, low vigor; and BAF55, high vigor) were soaked in water or 0.035 mM L^-1 GA₃. The imbibition curve displayed a triphasic pattern; however, exogenous GA₃ accelerated root emergence only in cultivar BAF44. GA₃ increased root growth only in cultivar BAF44, but increased hypocotyl and epicotyl lengths in both cultivars. GA₃ treatment improved seedling length in the low-vigor cultivar, resulting in more vigorous seedlings. This is likely due to increased gene expression and activity of alpha-amylase, leading to greater starch and total soluble sugar reduction in cotyledons, providing more energy for growth points. The initial seed vigor of beans is crucial for how GA₃ affects reserve mobilization dynamics.

Effects of copper nanoparticle treatment on the properties of hybrid corn seeds

2025-07-08T19:52:52+00:00

Corn (Zea mays L.), a vital crop economically and nutritionally, benefits from advancements like copper (Cu) nanoparticles, which are engineered to enhance crop growth and grain quality. This study aimed to assess the morphological, physical, chemical, and quality attributes of various corn hybrids (HB 01: 22S18 TOP2^®; HB 02: 20A30 VIPTERA^®; HB 03: 20A80 TOP2^®; HB 04: 22S18 TOP3^®, and HB 05: 20A20 TOP2^®) treated with copper nanoparticles (900 mg of Cu L^-1). Hybrid HB 04: 22S18 TOP3^® exhibited the highest levels of protein, lipids, fiber, and phosphorus, though calcium levels were comparable to other hybrids (p > 0.05). Fatty acid and amino acid profiles remained unchanged. Hybrids not treated with Cu nanoparticles had higher pH levels. The Cu nanoparticles primarily altered the surface, not the interior, of the seeds, with HB 02: 20A30 VIPTERA^® showing the highest Cu content. Overall, Cu nanoparticles preserved the physical and chemical properties of the corn grains, confirming their viability for seed treatment.

Effects of phosphate fertilization on growth and yield of irrigated sesame in semi-arid regions

2025-09-04T11:21:28+00:00

Exploring the effects of phosphorus on sesame development and yield in semi-arid environments is crucial for refining agronomic practices and enhancing crop productivity. This research evaluated the response of sesame cultivars to varying phosphorus levels under irrigation in a semi-arid setting. Conducted at the Experimental Farm of the Federal Rural University of the Semi-Arid, two experiments ran from August to November in 2021 and 2022. A randomized block design with subdivided plots and four replicates was employed. Treatments consisted of five phosphorus doses (0, 60, 120, 180, and 240 kg ha^-1 of P₂O₅) applied to main plots, while four sesame cultivars (CNPA G2, CNPA G3, CNPA G4, and BRS Seda) were assigned to subplots. Variables such as plant height, stem diameter, leaf count, capsule count, above-ground dry matter, thousand-seed weight, and seed yield were assessed. Phosphorus application significantly enhanced plant growth, which correlated positively with seed yield. Optimal phosphorus doses for peak seed yield in the first harvest were 170, 184, 167, and 152 kg ha^-1 of P₂O₅ for cultivars CNPA G2, CNPA G3, CNPA G4, and BRS Seda, respectively. The second harvest showed maximum yields at doses of 149, 137, 125, and 164 kg ha^-1 of P₂O₅. Notably, the second harvest yielded better plant development. Response to phosphorus varied among cultivars, with CNPA G3 and CNPA G4 showing the highest growth and productivity.

Vigor and damage of soybean seeds estimated by sequential Bayesian techniques in the tetrazolium test

2025-09-04T11:21:29+00:00

Soybean is an oilseed of great relevance to Brazil because it is one of the main crops produced in the country. The success of this crop depends on several factors, the main one being seed quality. The tetrazolium test has been used for quality control because in addition to evaluating the viability of germination and the vigor of the seed lots, it facilitates classification of the types of damage. Thus, the use of sequential sampling, which takes into account the immediate evaluation of each seed, may facilitate an earlier decision on viability and vigor without the need to evaluate all seeds as in the classic test as a formality of the method. In addition, the estimates obtained through Bayesian techniques can be improved by including prior information. The objective of this study was to study the application of Bayesian sequential tests to estimate the proportion of vigor in lots (binomial modeling) and the proportion of damage per category in soybean seeds (multinomial modeling) through the tetrazolium test. In each case, conjugate priors were used, and the parameters were elicited. It can be concluded that the four approaches, frequentist, Bayesian, sequential, and Bayesian sequential, were efficient for estimation of and decision-making about the parameters, with a reduction in the sample size. Moisture damage was present in 20.17% of the soybean seeds evaluated, damage by stink bugs in 3.50%, and mechanical damage, in the case of manual harvesting, in only 1.92%. In addition, 1.00% of seeds presented more than two types of damage.

Univariate and multivariate linear relationships among traits in sunflower cultivation

2025-09-04T11:21:28+00:00

Evaluating characteristics in sunflower cultivation through univariate and multivariate selection of agronomic traits and grain yield helps choose cultivars and hybrids, and supports crop breeding studies. Yet, the scientific literature relies on data from limited cultivation environments, potentially undermining result reliability. In this context, this study aimed to evaluate the linear relationships among morphological traits of sunflower in a low-altitude subtropical environment and identify traits that can assist in the indirect selection of cultivars, hybrids, and genotypes in field trials of the national sunflower genotype evaluation network. Data from five experimental years conducted annually between 2017/2018 and 2022/2023 were used. The experiments were conducted at the Federal University of Santa Maria (UFSM). The experimental design consisted of randomized blocks with four replications, considering 34 treatments (genotypes) evaluated over five experimental years, totaling 1,754 plants evaluated during the period. The evaluated traits were plant height (cm), capitulum diameter (cm), thousand-achene mass (g), number of achenes per capitulum, and individual achene yield per plant (g). Subsequently, the relationship among traits was investigated using Pearson correlation (r) and path (cause and effect) analyses. The traits number of achenes per capitulum, thousand-achene mass, and capitulum diameter are positively related. The magnitude of Pearson correlations among evaluated traits changes in an environment with prolonged water deficit conditions. The number of achenes per capitulum and thousand-achene mass have a linear relationship and a direct effect on individual achene yield. Capitulum diameter has a direct effect on the number of achenes per capitulum and can be used to assist in the indirect selection of sunflower genotypes, hybrids, and cultivars.

Productivity and quality of noble garlic cultivars under different vernalization temperatures

2025-09-04T11:21:27+00:00

Brazilian producers of noble garlic (Allium sativum L.) have sought to enhance the productivity and quality of garlic by applying a vernalization technique that induces bulb formation. The objective of this study was to evaluate the productivity and quality of garlic bulbs produced from different noble garlic cultivars at varying vernalization temperatures. The experiment was conducted in the experimental area of the Wehrmann Agricultural Group and was replicated three times on April 4^th (Experiment I), April 18^th (Experiment II), and May 16^th, 2019 (Experiment III). The experimental design consisted of a randomized complete block design in a 3 × 3 factorial scheme, with nine treatments and four replicates. The treatments consisted of three garlic cultivars: Quitéria, Ito, and Chonan, and three vernalization temperatures (-1 to -3°C; 1 to 3°C; and 2 to 4°C). After harvesting, the bulbs were counted, weighed, and classified based on sieves ranging from 2 to 8, according to the transverse bulb diameter. Following this classification, the commercial, total, and industrial bulb yields were estimated. Negative vernalization temperatures resulted in slower bulb development in all experiments; however, this was associated with a higher potential for bulb growth. Notably, the Chonan cultivar outperformed the other cultivars. Negative vernalization temperature increased the yield of bulbs in the 5–7 and 8 classes (higher commercial value classes), reduced the bulb yields in the 2–4 and industrial classes (lower commercial value classes), and enhanced the total yield.

Planting speed and coinoculation in soybeans

2025-09-04T11:21:26+00:00

Uniform seed distribution and an optimal plant stand are crucial for maximizing soybean yield. Additionally, a robust root system is essential for effective water and nutrient absorption through biological nitrogen fixation. This study investigated the impact of planting speed and coinoculation (Bradyrhizobium japonicum + Azospirillum brasilense) on plant distribution, nodulation, and soybean grain yield. Six field experiments were conducted during the 2018/19 and 2019/20 crop years in Santa Maria (two planting seasons per year) and Restinga Sêca, Brazil. The experiments utilized a randomized block design with four replications and treatments arranged in a 2 x 5 factorial design, assessing coinoculation (with and without) and five planting speeds. Results indicated that increasing planting speed reduced soil moisture and increased soil temperature, adversely affecting soybean nodulation and yield due to uneven plant distribution in the planting furrow. Planting speeds close to 4 km h^-1 achieved the best uniformity in plant distribution, nodulation, and soybean yield. Coinoculation enhanced the number and dry mass of nodules and improved soybean grain yield.

Postharvest quality of yellow passion fruit grown using espalier and trellis systems in an annual growth cycle

2025-09-04T11:21:25+00:00

Yellow passion fruit (Passiflora edulis) is a vine plant whose pulp is mainly used for juice production. Brazil accounts for approximately 90% of global passion fruit production, while Europe is an emerging market. Passion fruit cultivation requires support structures, typically oriented vertically using the espalier system or horizontally using the trellis system, constituting up to 70% of production costs. Despite its native origin, there is limited research on the impact of cultivation systems on fruit quality. This study compares trellis systems with two wires to the espalier system across two growing seasons under annual cultivation. Fruits were harvested when at least two-thirds of the skin turned yellow. Rainfall accumulation and light availability within each system were measured. Various fruit characteristics-including skin color, skin thickness, fruit mass, longitudinal and transverse diameters, pulp mass, pulp yield with seeds, total soluble solids, titratable acidity, and ascorbic acid content—were evaluated in both systems across both seasons. Results indicate that the trellis system consistently produced higher pulp mass and larger fruit diameter across seasons. No significant differences were found in postharvest quality between the systems. Based on these findings, the trellis system is recommended for annual yellow passion fruit cultivation.

Productive performance of canola hybrids and the contribution of winter crops to the productivity of soybean grown in succession

2025-09-04T11:21:25+00:00

Diversifying and rotating crops are of paramount importance in production systems; these practices aim to mitigate environmental risks and introduce new crops, thus supporting agricultural sustainability. Thus, the present study aimed to evaluate the productive performances of canola hybrids and to analyze the contribution of winter crops to the productivity of soybean grown in succession. Two experiments were conducted at two locations (Monsenhor Paulo and Luminárias, Minas Gerais, Brazil). The first experiment evaluated the performances of different canola hybrids: ALHT B4, Diamond, Hyola 433, Hyola 571 CL, Hyola 575 CL, and Nuola 300. The oil content (%), grain yield, and oil yield (kg ha^-¹) of the plants were assessed. The second experiment evaluated the performances of soybean varieties grown after canola, white oats, and a fallow period. The Diamond and ALTH B4 hybrids exhibited high grain and oil productivity levels in Monsenhor Paulo, MG. The Hyola 575 CL hybrid excelled in Luminárias and had the highest levels of grain and oil productivity. In both locations, soybean yield and stand density were not influenced by the preceding crop (canola or oats) or fallow period. Among the other evaluated characteristics, only plant height was affected in Monsenhor Paulo, MG, and was greater after oat cultivation. In Luminárias, MG, there was an increase in the number of pods after oat cultivation.

Response of wild Oryza spp. accessions and irrigated rice cultivars to Meloidogyne graminicola and M. ottersoni

2025-09-04T11:21:23+00:00

Root-knot nematodes (RKNs), including Meloidogyne graminicola and M. ottersoni, have recently been identified in Santa Catarina and Paraná in southern Brazil. Therefore, our study aimed to evaluate the host status of nine irrigated rice cultivars and five Oryza accessions inoculated with M. ottersoni and M. graminicola [initial population (IP) = 5,000 specimens] under greenhouse conditions across two experimental periods. We assessed the host status based on the nematode reproduction factor (RF) and the number of nematodes per gram of root. For both nematodes, all the rice cultivars we studied were classified as susceptible, with RF means ranging from 21.80 to 108.92 for M. ottersoni and 2.12 to 177.16 for M. graminicola. Conversely, the Oryza accessions displayed varied phenotypes. For example, O. grandiglumis, O. glaberrima, and O. glumaepatula exhibited moderate to high resistance to M. ottersoni, with RFs ranging from 0.53 to 4.50, while O. latifolia was susceptible. Additionally, O. glumaepatula showed moderate to high resistance levels to M. graminicola (RF = 0.23 – 8.88), whereas O. alta was susceptible, and O. grandiglumis, O. glaberrima, and O. latifolia demonstrated varying levels of resistance. Overall, our findings suggest that the Oryza accessions we studied could be promising sources of resistance for developing new cultivars in the future.

Physiological behavior of Cryptocarya aschersoniana seeds subjected to drying

2025-09-05T11:26:22+00:00

Seeds of Cryptocarya aschersoniana, as well as other species of the Lauraceae family, have frequently been reported to be sensitive to desiccation, which hinders their ex situ conservation. This study investigated the changes that occur during the drying of these seeds. Seeds harvested over 3 years were processed and dried at 20°C in boxes containing silica gel (with relative humidity ranging from 13.5 to 40%) to achieve a target water content of 40, 35, 30, 25, and 20%. For freshly harvested seeds, at each target water content, samples were taken, and germination tests were performed. Cell analyses were performed by using scanning electron and light microscopy (with reactions for starch and lipids). In addition, the sugars and lipid contents were determined. The results indicated that C. aschersoniana seeds are sensitive to desiccation and that under the conditions tested, the critical water content is approximately 30%, and the lethal water content is less than 18%. The seeds are dispersed while dormant, and this dormancy is partially overcome by partial drying. These seeds have some protection systems against desiccation, such as increased sucrose concentrations, during artificial drying; however, these systems are not efficient at protecting the seeds from damage caused by more intense desiccation. The images obtained allowed the verification of changes only at the point where the seeds were already completely unviable.

Accuracy assessment of bulk density measurement methods across different soil management practices: sample volume- and paraffin temperature-related errors

2025-03-11T17:28:55+00:00

Soil bulk density (BD) serves as a crucial physical property for characterizing soils and assessing the quality of their management systems. Various methods, including the Core, Clod, and Jolly balance (JBM) methods, are employed for BD measurement. However, these methods can yield significantly different measurements due to analytical errors. This study aims to assess the accuracy of these methods in a clayey Oxisol under different management conditions, while also identifying primary experimental errors in BD determination and strategies for their mitigation. Different statistical approaches were employed to analyze the impacts of sample volume, paraffin temperature, and management systems on BD determination methods. Method accuracy exhibited variation among management systems, particularly notable in secondary forest (SF) areas. In these areas, Core-based BD measurements were 37% lower than those obtained by the Clod and JBM methods. This disparity can be attributed to the higher macroporosity observed in SF, leading to greater sample volume loss and smaller volumes analyzed by the Clod and JBM. A correlation between paraffin temperature for sample coating and clod volume was observed, with paraffin temperature affecting BD measurements only in clods larger than 69.9 cm³. The paraffin temperature inducing the lowest mean error for larger clods was 92°C. For clods smaller than 69.9 cm³, BD measurement errors arose due to inadequate sample volume. Representative elementary volume was identified as a means to mitigate BD overvaluation by the Clod method. A volume of 99 cm³ proved effective in reducing mean BD errors to 5%, making it suitable for both field sampling and laboratory analytical procedures.

Changes in chemical attributes and fractions of organic matter in a Xanthic Ferralsol under different management systems

2025-04-22T17:44:00+00:00

Examining organic matter fractions is crucial for comprehending variations in soil organic carbon (C) content resulting from the type of management used. The aim of this study was to assess the impact of management systems that utilize both organic and mineral fertilization on soil chemical attributes and organic matter fractions in the Xanthic Ferralsol. This study was conducted in the experimental areas of Embrapa Mandioca and Fruticultura, Cruz das Almas, Bahia State, Brazil. Three cassava and banana production systems, a conventional cassava cultivation system (CAS-CT), an organic banana system (BAN-ORG), and a conventional banana system (BAN-CT), were investigated using the native forest (NF) area as a reference. Soil sampling was conducted within the planting rows at depths of 0.0 - 0.10 and 0.10 - 0.20 m. Macronutrients, soil pH, soil total organic C, particulate organic C, light organic matter, labile-C, mineralizable C, and microbial biomass-C were assessed. BAN-ORG led to an increase in soil pH at both depths. Principal component (PC) analysis showed that organic cultivation was distinguished from the others owing to its strong correlation with soil bases (Ca and Mg), particulate organic C, and labile-C. In the NF and BAN-ORG soils, microbial-C levels in the 0.0 - 0.10 and 0.10 - 0.20 m layers remained consistent, whereas there was a reduction of 30 and 70% for CAS-CT and BAN-CT, respectively, with increasing depth. Mineralizable C (release of CO₂-C) was higher in the NF and BAN-ORG systems than in the conventional system for both evaluated layers. BAN-CT and CAS-CT were strongly correlated with available potassium in PC-2, separating them from BAN-ORG and NF. Management practices implemented in the organic system resulted in an increase in macronutrient levels and a reduction in soil acidity. The elevation of labile-C and particulate organic C in the organic system increased the microbial activity in the soil, particularly in the subsurface layers. Organic management has emerged as a viable approach for enhancing organic C sequestration in the soil and creating favorable conditions for increasing microbial activity in banana cultivation.

Termite activity in tropical and subtropical Brazilian soils

2025-07-08T19:53:27+00:00

Termites, key members of the soil macrofauna, play a significant role in bioturbating soil through their construction activities, essential for their mobility and survival. Despite extensive studies on the alterations caused by mound construction, the full impact on soils, particularly in the Americas, remains inadequately understood. This study hypothesized that termites selectively engage with specific soil materials, a theory tested by comparing the sand and clay fractions of soils and mounds at six sites across five Brazilian states. Sedimentological analyses were performed on the sand fraction, while the mineral fraction underwent X-ray diffraction, magnetic susceptibility, and selective iron oxide dissolution tests. The findings reveal that termites prefer smaller sand particles when constructing mounds in sandier soils. In most locations, termites concentrated up to 79.9% of Fe and 65.3% of Al from pedogenic iron and aluminum oxides, and up to 31.1% of Fe from poorly crystalline forms. Magnetic susceptibility measurements indicated minimal differences in magnetic minerals between mounds and soils. Termites do not alter the mineral composition of highly weathered soils, which primarily consist of kaolinite, gibbsite, and iron oxides. However, they selectively target clay-sized particles in sandy soils. Therefore, termites are not considered weathering agents in highly weathered soils dominated by stable minerals. These results underscore the significant role of termites as bioturbators in soil dynamics.

Soil phosphorus fractions in response to cropping system, liming, and phosphate fertilization in an expanding sugarcane plantation area

2025-07-08T19:53:17+00:00

The forms of phosphorus (P) present in soil are not stable and permanent. The sequential fractionation of soil P allows us to understand the dynamics of this nutrient in the soil. This study identifies alterations in P forms within the soil, induced by the processes of liming, phosphating, and cover crop cultivation preceding the planting of sugarcane, within an environment marked by constraints on sugarcane expansion. Employing a randomized block experimental design with sub-split plots and three replications, two lime doses (6 Mg ha^-1 and 12 Mg ha^-1) were assessed in the primary plots. Subsequently, the impact of three distinct species-Glycine max, Crotalaria spectabilis, and Crotalaria juncea remnant-cultivated following the Urochloa brizanta cultivar Xaraés, was evaluated in the subplots, preceding the introduction of Saccharum officinarum. Further refinement involved the examination of three Phosfaz calcined thermophosphate doses (0, 380, and 760 kg ha^-1) administered on the spot in the sub-subplots and incorporated with limestone and gypsum. The experiment unfolded under field conditions, and soil samples were collected at depths of 0 to 0.1 m, 0.1 to 0.2 m, and 0.2 to 0.4 m for the purpose of conducting phosphorus fractionation. Liming, phosphating, and antecedent crops to sugarcane cultivation exhibited varying impacts on the forms of P in the assessed soil layers. Generally, the application of limestone at a dosage exceeding that required for soil acidity correction (12 Mg ha^-1), coupled with corrective fertilization involving 380 kg ha^-1 of thermophosphate and the cultivation of Crotalaria juncea, resulted in an augmented content of labile phosphorus up to the 0.4 m soil layer. These findings suggest that liming, phosphating, and cultural practices-particularly involving Crotalaria juncea cultivation-have the potential to enhance phosphorus availability during the renewal of sugarcane fields.

Long-term successive poultry litter application improves Oxisol fertility in the Brazilian Cerrado

2025-09-04T11:21:24+00:00

Brazilian Savannah (Cerrado) soils have insufficient nutrient concentrations for attaining high crop yields. Properly applied poultry litter (PL) may improve soil fertility and forage productivity. Herein, we aimed to evaluate the vertical distribution of acidity and nutrient availability in an Oxisol (Latossolo Vermelho distroférrico) subjected to increasing PL doses over 7 years. We determined the vertical distribution and levels of total organic C, total N, Ca, Mg, K, P, and pH in seven soil layers (0–0.05, 0.05–0.10, 0.10–0.20, 0.20–0.30, 0.30–0.50, 0.50–0.75, and 0.75–1.00 m) where four different PL treatments were applied (cumulative levels: 0, 26.32, 43.15, and 57.6 Mg ha⁻¹) over seven years. Potential acidity and low total organic C content indicated the chemical limitations of natural soil. The application of PL reduced soil acidity and increased K, Ca, and Mg levels and base saturation to 1.00-m depth. The highest PL dose (57.6 Mg ha⁻¹) increased the vertical mobility of Ca, K, and Mg while increasing their stocks by 157, 140, and 135%, respectively, in the deeper soil layers. However, even in the long term, the tested PL doses did not increase total organic C, total N, or P levels in the subsurface soil layers. The dual effects of soil acidity correction and improved nutrient content attest to PL application as an effective strategy for improving soil fertility and ensuring sustainable agricultural development in the Brazilian Cerrado.

Use of visibility graphs for analysis of computed tomography soil images

2025-09-05T11:27:44+00:00

A complex network analysis of three-dimensional soil images obtained by X-ray computed tomography (CT) was employed to analyze the morphological properties of soil under different vegetation covers. This study quantitatively assessed changes in the three-dimensional soil structure due to disturbances caused by sugarcane management techniques. We used CT images of soil covered by the Atlantic Forest and sugarcane with 624,100 voxel columns each to examine topological indices of the networks generated from the vertical lines of the CT images using the visibility graph (VG) method. The VG method successfully described the changes in the structure of the soil samples by comparing the CT images and may be used to quantify soil degradation. The topological indices clustering coefficient, average shortest path, and average degree of the VG network described the communication between soil structural units, pore continuity, and the distribution of paths between pores. We found strong correlations between the phenomenological aspects and the topological descriptors of the generated network, especially for the average degree. This index best highlighted the difference between the samples, revealing greater heterogeneity in the Atlantic Forest sample compared to the sugarcane sample. These correlations indicate that the complexity of the networks of 3D soil images is related to physical properties, enabling quantification of the degradation of soil morphological properties.