Determining Factors and Economic Injury Levels for Sphenophorus levis for Chemical and Biological Control in Irrigated and Non-irrigated Sugarcane Crops.

Globally, people use sugarcane (Saccharum officinarum) to produce sugar and ethanol. Rainfed or irrigated sugarcane agricultural systems are available. Among the pests affecting this crop, the weevil Sphenophorus levis, Vaurie 1978 (Coleoptera: Curculionidae), is increasingly becoming a significant threat in southern South America. Sphenophorus levis populations are controlled using chemical or biological measures. Control decisions hinge upon the economic injury level (EIL). The EIL delineates the pest density that results in financial losses for producers. This study aims to determine the EIL for S. levis, considering the factors favoring this insect pest and chemical and biological control methods in rainfed and irrigated systems. The intensity of S. levis attacks was monitored in commercial sugarcane plantations over four years in João Pinheiro, Minas Gerais, Brazil. Sampling occurred in a 50 × 50 × 30-cm-deep trench dug in the soil surrounding the sugarcane clump. The total number of stumps in the clump, including those attacked by S. levis, was tallied. The EILs for this pest were 5.93% and 4.85% of targeted stumps for chemical control in rainfed and irrigated crops, respectively. Biological control in sugarcane plots resulted in an EIL of 4.15% and 3.40% for stumps attacked in rainfed and irrigated crops, respectively. Pest attacks were more severe during rainy years and in older sugarcane crops. The EIL values determined in this study could inform integrated pest management programs for sugarcane crops.

Agronomic performance and technological quality of sugarcane submitted to different poultry litter dosages.

Sugarcane is a central crop for sugar and ethanol production. Investing in sustainable practices can enhance productivity, technological quality, mitigate impacts, and contribute to a cleaner energy future. Among the factors that help increase the productivity of sugarcane, the physical, chemical and biological parameters of the soil are amongst the most important. The use of poultry litter has been an important alternative for soil improvement, as it acts as a soil conditioner. Therefore, this work aimed to verify the best doses of poultry litter for the vegetative, reproductive and technological components of sugarcane. The experiment was carried out at Usina Denusa Destilaria Nova União S/A in the municipality of Jandaia, GO. The experimental design used was a complete randomized block design with four replications: 5 × 4, totaling 20 experimental units. The evaluated factor consisted of four doses of poultry litter plus the control (0 (control), 2, 4, 6 and 8 t ha-1). In this study, were evaluated the number of tillers, lower stem diameter, average stem diameter, upper stem diameter, plant height, stem weight and productivity. The technological variables of total recoverable sugar, recoverable sugar, Brix, fiber, purity and percentage of oligosaccharides were also evaluated. It was observed, within the conditions of this experiment, that the insertion of poultry litter did not interfere significantly in most biometric, productive and technological variables of the sugarcane. But it can also be inferred that there was a statistical trend toward better results when the sugarcane was cultivated with 4 t ha-1 of poultry litter.

Beneficial Effect of Exogenously Applied Calcium Pyruvate in Alleviating Water Deficit in Sugarcane as Assessed by Chlorophyll a Fluorescence Technique.

The growing demand for food production has led to an increase in agricultural areas, including many with low and irregular rainfall, stressing the importance of studies aimed at mitigating the harmful effects of water stress. From this perspective, the objective of this study was to evaluate calcium pyruvate as an attenuator of water deficit on chlorophyll a fluorescence of five sugarcane genotypes. The experiment was conducted in a plant nursery where three management strategies (E1-full irrigation, E2-water deficit with the application of 30 mM calcium pyruvate, and E3-water deficit without the application of calcium pyruvate) and five sugarcane genotypes (RB863129, RB92579, RB962962, RB021754, and RB041443) were tested, distributed in randomized blocks, in a 3 × 5 factorial design with three replications. There is dissimilarity in the fluorescence parameters and photosynthetic pigments of the RB863129 genotype in relation to those of the RB041443, RB96262, RB021754, and RB92579 genotypes. Foliar application of calcium pyruvate alleviates the effects of water deficit on the fluorescence parameters of chlorophyll a and photosynthetic pigments in sugarcane, without interaction with the genotypes. However, subsequent validation tests will be necessary to test and validate the adoption of this technology under field conditions.

Designing and validation of specific primers for the quantitative detection of bacteria in sugarcane inoculant.

Endophytic diazotrophic plant growth-promoting bacteria Herbaspirillum rubrisubalbicans (HCC103), Herbaspirillum seropedicae (HRC54), Paraburkholderia tropica (Ppe8T), Gluconacetobacter diazotrophicus (Pal5T), and Nitrospirillum amazonense (CBAmC) have been used as inoculants for sugarcane. The genome sequences of these strains were used to design a set of specific primers for the real-time PCR (qPCR) assay. Primer specificity was confirmed by conventional PCR using the genomic DNAs of 25 related bacterial species and the five target strains. The qPCR assays were conducted using root and shoot samples from two sugarcane varieties (RB867515 and RB92579). These samples were collected both with and without inoculation, using the target strains specified in this study. The sugarcane plants were grown in a greenhouse, utilizing a substrate composed of sterile sand and vermiculite in a 2:1 ratio, for a duration of 55 days. The primers designed for this study successfully amplified target DNA fragments from each of the bacterial species, enabling their differentiation at the species level. The total bacterial population present in the sugarcane quantified using qPCR was on average 105.2 cells g-1 of fresh tissue. Across both evaluated varieties, it was observed that the population of inoculated bacteria tended to decrease over time and became more concentrated in the sugarcane roots compared to the aerial parts. The qPCR results suggest that both the host and the microbes influence the endophytic population and the bacterial number decreases with plant age.

Espectroscopía visible y del infrarrojo cercano para el análisis de nutrientes en tejido vegetal de caña de azúcar para producción de panela

La espectroscopía de reflectancia en el infrarrojo cercano (NIRS) es una tecnología rápida, multiparamétrica, amigable con el ambiente, de bajo costo y gran exactitud, para el análisis de diversos componentes en alimentos, en suelo y en agricultura. El objetivo del presente estudio fue construir modelos de calibración NIRS, para la predicción de nutrientes en tejido vegetal de caña de azúcar, para producción de panela, cultivada en la región de la Hoya del río Suárez. Un total de 416 muestras de tejido fueron escaneadas en el segmento espectral Vis-NIR. El análisis quimiométrico, se realizó con el software WinISI V4.10, aplicando la regresión de mínimos cuadrados parciales modificados, junto a una validación cruzada. Se evaluaron cuatro modelos con diferentes tratamientos matemáticos y el rendimiento de las calibraciones, se hizo por medio de la validación externa, analizando las medidas de bondad de ajuste, como el coeficiente de determinación de la predicción, el error estándar de la predicción ajustado por el sesgo y la desviación predictiva residual. Los resultados muestran que el modelo de calibración para N presentó el mayor poder predictivo. Para macronutrientes, las calibraciones, con mayor poder predictivo, fueron P y K y para micronutrientes, el modelo para B, mientras que para Cu presentó el más bajo poder predictivo. Se encontraron modelos adecuados para la predicción de los contenidos de N, Ca y P; para los demás nutrientes, se recomienda ampliar el conjunto de calibración.

Near Infrared Reflectance Spectroscopy (NIRS) is a fast, multiparametric, environmentally friendly, low-cost, and highly accurate technology for the analysis of components in food, soil, and agriculture. The purpose of this study was to generate NIRS calibration models for the prediction of nutrients in plant tissue of sugarcane to panela production cultivated in the Hoya del Río Suárez region. A total of 416 tissue samples were scanned in Vis-NIR spectral segment. Chemometric analysis was performed with the WinISI V4.10 software applying modified partial least squares regression with cross-validation. Four models with different mathematical treatments were evaluated, and the performance of calibrations was made through external validation analyzing the goodness-of-fit measures as prediction determination coefficient, standard error of the bias-adjusted prediction, and residual predictive deviation. The results showed that the calibration model for N had the highest predictive power. For macronutrients, the calibrations with the best predictive power were for P and K, and micronutrients for B, while Cu presented the lowest predictive power. Adequate models were found for the prediction of N, Ca, and P. In the case of the other nutrients, it is recommended to expand the calibration set.

In vivo and in silico comparison analyses of Cry toxin activities toward the sugarcane giant borer.

The sugarcane giant borer, Telchin licus licus, is an insect pest that causes significant losses in sugarcane crops and in the sugar-alcohol sector. Chemical and manual control methods are not effective. As an alternative, in the current study, we have screened Bacillus thuringiensis (Bt) Cry toxins with high toxicity against this insect. Bioassays were conducted to determine the activity of four Cry toxins (Cry1A (a, b, and c) and Cry2Aa) against neonate T. licus licus larvae. Notably, the Cry1A family toxins had the lowest LC50 values, in which Cry1Ac presented 2.1-fold higher activity than Cry1Aa, 1.7-fold larger than Cry1Ab, and 9.7-fold larger than Cry2Aa toxins. In silico analyses were performed as a perspective to understand putative interactions between T. licus licus receptors and Cry1A toxins. The molecular dynamics and docking analyses for three putative aminopeptidase N (APN) receptors (TlAPN1, TlAPN3, and TlAPN4) revealed evidence for the amino acids that may be involved in the toxin-receptor interactions. Notably, the properties of Cry1Ac point to an interaction site that increases the toxin's affinity for the receptor and likely potentiate toxicity. The interacting amino acid residues predicted for Cry1Ac in this work are probably those shared by the other Cry1A toxins for the same region of APNs. Thus, the presented data extend the existing knowledge of the effects of Cry toxins on T. licus licus and should be considered in further development of transgenic sugarcane plants resistant to this major occurring insect pest in sugarcane fields.

Bioactive compounds as an alternative for the sugarcane industry: Towards an integrative approach.

Here, a comprehensive review of sugarcane industrialization and its relationship with bioactive compounds (BCs) detected in various products and by-products generated during its processing is presented. Furthermore, it is discussed how these compounds have revealed important antioxidant, antineoplastic, antidiabetic, and antimicrobial activities. From this bibliographic research highlights the significance of two types of BCs of natural origin (phenolic compounds (PCs) and terpenoids) and a group of compounds synthesized during industrial transformation processes (Maillard reaction products (MRPs)). It was found that most of the studies about the BCs from sugarcane have been conducted by identifying, isolating, and analyzing ones or a few compounds at a specific period, this being a conventional approach. However, given the complexity of the synthesis processes of all these BCs and the biological activities they can manifest in a specific biological context, novel approaches are needed to address these analyses holistically. To overcome this challenge, integrating massive and multiscale methods, such as omics sciences, seems necessary to enrich these studies. This work is intended to contribute to the state of the art that could support future research about the exploration, characterization, or evaluation of different bioactive molecules from sugarcane and its derivatives.

New approaches to the effects of Si on sugarcane ratoon under irrigation in Quartzipsamments, Eutrophic Red Oxisol, and Dystrophic Red Oxisol.

BACKGROUND: C:N:P homeostasis in plants guarantees optimal levels of these nutrients in plant metabolism. H However, one of the causes to the effects of deficit irrigation is the loss of C:N:P homeostasis in leaves and stems that causes reduction in the growth of sugarcane. Being able to measure the impact of water deficit on C:N:P homeostasis in plants from the stoichiometric ratios of the concentrations of these nutrients in leaves and stems. This loss causes a decrease in nutritional efficiency, but can be mitigated with the use of silicon. Silicon favors the homeostasis of these nutrients and crop productivity. The magnitude of this benefit depends on the absorption of Si by the plant and Si availability in the soil, which varies with the type of soil used. Thus, this study aims to evaluate whether the application of Si via fertigation is efficient in increasing the absorption of Si and whether it is capable of modifying the homeostatic balance of C:N:P of the plant, causing an increase in nutritional efficiency and consequently in the production of biomass in leaves and stems of sugarcane ratoon cultivated with deficient and adequate irrigations in different tropical soils. RESULTS: Water deficit caused biological losses in concentrations and accumulation of C, N, and P, and reduced the nutrient use efficiency and biomass production of sugarcane plants cultivated in three tropical soils due to disturbances in the stoichiometric homeostasis of C:N:P. The application of Si increased the concentration and accumulation of Si, C, N, and P and their use efficiency and reduced the biological damage caused by water deficit due to the modification of homeostatic balance of C:N:P by ensuring sustainability of the production of sugarcane biomass in tropical soils. However, the intensity of attenuation of such deleterious effects stood out in plants cultivated in Eutrophic Red Oxisols. Si contributed biologically by improving the performance of sugarcane ratoon with an adequate irrigation due to the optimization of stoichiometric ratios of C:N:P; increased the accumulation and the use efficiency of C, N, and P, and promoted production gains in biomass of sugarcane in three tropical soils. CONCLUSION: Our study shows that fertigation with Si can mitigate the deleterious effects of deficient irrigation or potentiate the beneficial effects using an adequate irrigation system due to the induction of a new stoichiometric homeostasis of C:N:P, which in turn improves the nutritional efficiency of sugarcane cultivated in tropical soils.

Calcium pyruvate in the attenuation of the water deficit on the agro-industrial quality of ratoon sugarcane / Piruvato de cálcio na atenuação do déficit hídrico sobre a qualidade agroindustrial de cana soca

Abstract Sugarcane is one of the largest agricultural commodities when considering the export volume and the number of jobs generated. Sugarcane production in the Brazilian Northeast region is generally low due to several factors, including the irregular rainfall distribution, which highlights the importance of studies aimed at mitigating the deleterious effects of water stress. In this scenario, this study aimed to evaluate calcium pyruvate as a water deficit attenuator on the agro-industrial quality of sugarcane in the second cycle of cultivation. The experiment was conducted out under greenhouse conditions of the Federal University of Campina Grande, where five sugarcane commercial genotypes tested (G1- RB863129, G2- RB92579, G3- RB962962, G4- RB021754, and G5- RB041443) and three irrigation management strategies (E1- full irrigation, E2- water deficit with application of 30 mM of calcium pyruvate, and E3- water deficit without calcium pyruvate application), distributed in randomized blocks in 5 × 3 factorial arrangement with three replications. The RB021754 genotype under water deficit and without foliar application of calcium pyruvate increased the fiber content (13.2%) and the sugarcane moist cake weight (143.5 g). The effects of water deficit in sugarcane genotypes are attenuated by the exogenous application of 30 mM of calcium pyruvate, with benefits on the polarized sucrose content, apparent sucrose content of the juice, soluble solids content, purity, corrected cane POL, total recoverable sugars, and stem mass in relation to plants under water deficit without calcium pyruvate application.

Resumo A cana-de-açúcar é uma das maiores commodities agrícolas, quando se considera o volume de exportação e o número de empregos gerados. A produção no Nordeste brasileiro, em geral, é baixa, decorrente de diversos fatores, entre eles, a irregularidade de distribuição das chuvas, o que realça a importância de estudos com vistas a minorar os efeitos deletérios do estresse hídrico. Nesse cenário, objetivou-se avaliar o piruvato de cálcio como atenuante do déficit hídrico sobre a qualidade agroindustrial da cana-de-açúcar no segundo ciclo de cultivo. O experimento foi conduzido em casa de vegetação da Universidade Federal de Campina Grande, onde foram testados cinco genótipos de cana-de-açúcar (G1- RB863129, G2- RB92579, G3- RB962962, G4- RB021754 e G5- RB041443) submetidos a três estratégias de manejo da irrigação (E1- Irrigação plena, E2- déficit hídrico com aplicação de 30 mM de piruvato de cálcio e E3- déficit hídrico sem aplicação de piruvato de cálcio), distribuídos em blocos casualizados, em esquema fatorial 5 × 3, com três repetições. O genótipo RB021754 sob déficit hídrico e sem aplicação foliar do piruvato de cálcio aumentou o teor de fibra (13,2%) e o peso do bolo úmido da cana (143,5 g). Os efeitos do déficit hídrico em genótipos de cana-de-açúcar são atenuados com aplicação exógena de 30 mM de piruvato de cálcio, com benefícios sobre o teor sacarose polarizada, teor de sacarose aparente do caldo, teor de sólidos solúveis, pureza, pol da cana corrigida, açúcares totais recuperáveis e massa de colmos, em relação as plantas sob déficit hídrico sem aplicação de piruvato de cálcio.

Filter cake increases sugarcane yield / A torta de filtro aumenta a produtividade da cana-de-açúcar

Sugarcane cultivation stands out in Brazilian agribusiness, covering more than eight million hectares for the production of sugar, ethanol, and by-products. Fertilization is one of the limiting factors in sugarcane yield, for which filter cake is a viable solution to meet plant nutritional needs. This study aimed to assess the effect of enriched filter cake on gas exchange and yield in RB041443 sugarcane, cultivated in soils of the coastal tablelands of Paraíba, Brazil. The experiment was conducted in the Monte Alegre S/A sugarcane mill, in the municipality of Mamanguape, using a randomized blocks experimental design, with 12 treatments (T1- cake, T2- cake + MAP, T3- cake + gypsum, T4 - cake + phosphate, T5- cake + bagasse, T6- cake + MAP + gypsum, T7- cake + MAP + phosphate, T8- cake + MAP + bagasse, T9- cake + gypsum + phosphate, T10- cake + gypsum + bagasse, T11- cake + phosphate + bagasse, and T12- control (only MAP)), and 4 replications, totaling 48 plots. A significant effect (5% probability) was also observed for the variables number of leaves and tons of stem per hectare (TSH). T1- cake, T4- cake + phosphate, T6- cake + MAP + gypsum and T10- cake + gypsum + bagasse, had the best results for TSH, with yields greater than 140 t ha-1. Regarding stomatal conductance, the highest values were obtained in T6 and T8, which, together with T11, had the highest gs values. Concerning the internal carbon concentration, T1, T2, T6, and T8 stood out. T6 also had a significant effect on transpiration. From this study, it was concluded that the use of enriched filter cake as a base fertilizer in sugarcane culture contributes to increasing the yield of the RB041443 variety, generating positive responses for plant gas exchange, being T1 and T10 indicated to increase the production in the sugar-energy sector.

A cultura da cana-de-açúcar ocupa uma posição de destaque para o agronegócio brasileiro, abrangendo mais de oito milhões de hectares na produção de açúcar, etanol e subprodutos. Um dos fatores limitantes na produtividade da cana-de-açúcar é a questão da adubação, sendo a torta de filtro uma solução viável para suprir as necessidades nutricionais da planta. Com esse estudo, objetivou-se avaliar o efeito do uso da torta de filtro enriquecida sob as trocas gasosas e produtividade da variedade de cana-de-açúcar RB041443 cultivada em solos dos tabuleiros costeiros da Paraíba. O experimento foi conduzido na Usina Monte Alegre S/A, no município de Mamanguape-PB, utilizando o delineamento experimental em blocos casualizados com 12 tratamentos (T1- Torta, T2- Torta + MAP, T3- Torta + Gesso, T4 - Torta + Fosfato, T5- Torta + Bagaço, T6- Torta + MAP + Gesso, T7- Torta + MAP + Fosfato, T8- Torta + MAP + Bagaço, T9- Torta + Gesso + Fosfato, T10- Torta + Gesso + Bagaço, T11 - Torta + Fosfato + Bagaço, e T12 - Testemunha (Apenas MAP)), 4 repetições, totalizando 48 parcelas. Efeito significativo a 5% também foi observado para a variável número de folhas e tonelada de colmo por hectare. Para a variável TCH, os melhores resultados foram obtidos nos tratamentos T1- Torta, T4-Torta + Fosfato, T6- Torta + MAP + Gesso e T10- Torta + Gesso + Bagaço, com produtividades superiores a 140 t ha-1. Para a condutância estomática, resultados superiores foram obtidos no T6 e T8, que, junto ao T11, agruparam-se com os maiores valores de gs. Em relação a concentração interna de carbono, destacaram-se os tratamentos T1, T2, T6 e T8. Para a variável transpiração, o T6 apresentou influência significativa da torta de filtro. Com o referido estudo, concluiu-se que a utilização da torta de filtro enriquecida como adubação de fundação na cultura da cana-de-açúcar possibilita aumento no rendimento produtivo da variedade RB 041443, bem como respostas positivas para as trocas gasosas da planta, sendo os tratamentos T1 e T10 indicados para aumentar a produção do setor sucroenergético.

Impact of Si on C, N, and P stoichiometric homeostasis favors nutrition and stem dry mass accumulation in sugarcane cultivated in tropical soils with different water regimes.

Studies with silicon (Si) in sugarcane indicate a greater response in productivity in plants under stress, and the underlying mechanisms of Si in the crop are poorly reported. In this context, the benefits of Si in the crop's stem production are expected to occur at the C:N:P stoichiometry level in plant tissues, benefiting plants with and without stress. However, the extension of this response may vary in different soils. Thus, this research aimed to evaluate if fertigation with Si modifies the C:N:P stoichiometry and if it can increase sugarcane's nutritional efficiency and vegetative and productive parameters. Therefore, three experiments were installed using pre-sprouted seedlings to cultivate sugarcane in tropical soils belonging to the Quartzarenic Neosol, Eutrophic Red Latosol, and Dystrophic Red Latosol classes. The treatments comprised a 2 × 2 factorial scheme in each soil. The first factor was composed without water restriction (water retention = 70%; AWD) and with water restriction (water retention = 35%; PWD). The second factor presented Si concentrations (0 mM and 1.8 mM) arranged in randomized blocks with five replications. Fertigation with Si increases the Si and P concentration, the C and N efficiency, the C:N ratio, and the dry mass production. However, it decreases the C and N concentration and the C:P, C:Si, and N:P ratios in sugarcane leaves and stems regardless of the water regime adopted in the three tropical soils. Cluster and principal components analysis indicated that the intensity of the beneficial effects of Si fertigation on sugarcane plants varies depending on the cultivation soil and water conditions. We found that Si can be used in sugarcane with and without water stress. It changes the C:N:P homeostasis enough to improve the nutritional efficiency of C, P, N, and, consequently, the dry mass accumulation on the stems, with variation in the different cultivated soils.

Silicon as a Sustainable Option to Increase Biomass With Less Water by Inducing Carbon:Nitrogen:Phosphorus Stoichiometric Homeostasis in Sugarcane and Energy Cane.

Climate change has prolonged periods of water deficit in sugarcane and energy cane crops. This condition induces an imbalance of the carbon (C): nitrogen (N): phosphorus (P) stoichiometric homeostasis, impairing accumulated nutrients from being converted into biomass. Silicon (Si) supplementation can mitigate the damage caused by water deficit in plants by improving the C:N:P balance, increasing C, N, and P use efficiencies and the biomass conversion, and reducing climate change effects on crops. This study assesses the beneficial effects of Si applied through fertigation associated with foliar spraying on the alleviation of damage caused by severe water deficit in sugarcane and energy cane for intermediate and long periods. In addition, the effects in maintenance of nutritional homeostasis we assessed and C, N, and P use efficiencies on sugarcane and energy cane under those conditions were increased. Four experiments were conducted during the first growth cycle of each species. The effect of fertigation associated with Si foliar spraying was evaluated by applying Si only during the seedling formation phase in sugarcane and energy cane grown under severe water deficit for 60 days after transplanting (intermediate period). Then, the effect of Si applied during seedling formation and supplemented after transplanting was evaluated in sugarcane and energy cane grown under severe water deficit for 160 days after transplanting (long period). The Si supply decreased C contents, modified the C:N:P ratio, and increased C, N, and P use efficiencies in plants of both species under water deficit at the intermediate and long periods after transplanting. The effects of applying Si through fertigation associated with foliar spraying during seedling formation mitigated the damage caused by severe water deficit in the intermediate period, which was mainly observed in sugarcane. When supplemented with Si after transplanting, the mitigating effects occurred in both species under severe long period water deficit. Therefore, the Si supply through fertigation associated with foliar spraying is a viable alternative to provide Si to the plant. It also comes with beneficial effects that partially reverse the damage to nutritional homeostasis and increase nutritional efficiency in plants under severe water deficit.

Sugarcane yield and quality using soil magnetic susceptibility

The concept of production environments, which is widely used to classify the yield potential of soils, and magnetic susceptibility (MS), is emerging as an important tool for mapping ultra-detailed areas. Given this background, this paper aims to evaluate the use of MS as a tool for the identification of areas with different potential the enhancing of sugarcane yield and quality, and the allocation of varieties. An area of 445 ha was sampled at 1 point every 7 ha, and 14 points were determined for stratified sampling following the top of the landscape. Particle size and MS of samples at depths of 0.0-0.2 and 0.2-0.4 m were analyzed. The data on yield and quality of raw material were obtained from a nine crop season database and biometry performed in the 2018/19 crop season. The multivariate analysis of historical results showed the formation of three groups with different yield and quality potential, with a difference of up to 17.28 mg of cane per hectare between the group with the highest and lowest potential, based on soil MS. An analysis of the performance of the varieties involved showed that MS is effective in identifying areas with different potential for sugarcane yield and quality, differentiating by up to 34.5 % the performance of the same variety in different MS classes and by up to 38.5 % the performance of different varieties in similar MS classes. Thus, MS is an effective tool for identifying areas with different potential for sugarcane yield and quality, and can be used for allocating varieties in the field.

Novel Tools for Adjusting Spatial Variability in the Early Sugarcane Breeding Stage.

The detection of spatial variability in field trials has great potential for accelerating plant breeding progress due to the possibility of better controlling non-genetic variation. Therefore, we aimed to evaluate a digital soil mapping approach and a high-density soil sampling procedure for identifying and adjusting spatial dependence in the early sugarcane breeding stage. Two experiments were conducted in regions with different soil classifications. High-density sampling of soil physical and chemical properties was performed in a regular grid to investigate the structure of spatial variability. Soil apparent electrical conductivity (ECa) was measured in both experimental areas with an EM38-MK2® sensor. In addition, principal component analysis (PCA) was employed to reduce the dimensionality of the physical and chemical soil data sets. After conducting the PCA and obtaining different thematic maps, we determined each experimental plot's exact position within the field. Tons of cane per hectare (TCH) data for each experiment were obtained and analyzed using mixed linear models. When environmental covariates were considered, a previous forward model selection step was applied to incorporate the variables. The PCA based on high-density soil sampling data captured part of the total variability in the data for Experimental Area 1 and was suggested to be an efficient index to be incorporated as a covariate in the statistical model, reducing the experimental error (residual variation coefficient, CVe). When incorporated into the different statistical models, the ECa information increased the selection accuracy of the experimental genotypes. Therefore, we demonstrate that the genetic parameter increased when both approaches (spatial analysis and environmental covariates) were employed.

Trichoderma asperellum Inoculation as a Tool for Attenuating Drought Stress in Sugarcane.

Drought stress is an important concern worldwide which reduces crop yield and quality. To alleviate this problem, Trichoderma asperellum has been used as a plant growth-promoting fungus capable of inducing plant tolerance to biotic and abiotic stresses. Here, we examined the effect of T. asperellum inoculation on sugarcane plant above and belowground development under drought stress and investigated the role of this fungus on inducing tolerance to drought at physiological and biochemical levels. The experiment was performed in pots under greenhouse conditions, with four treatments and four replicates. The treatments consisted of sugarcane plants inoculated or not with T. asperellum and grown under drought stress and adequate water availability. Drought-stressed sugarcane plants inoculated with T. asperellum changed the crop nutrition and chlorophyll and carotenoid concentrations, resulting in increased photosynthesis rate, stomatal conductance, and water use efficiency compared to the non-inoculated plants. In addition, the antioxidant metabolism also changed, increasing the superoxide dismutase and peroxidase enzyme activities, as well as the proline concentration and sugar portioning. These cascade effects enhanced the root and stalk development, demonstrating that T. asperellum inoculation is an important tool in alleviating the negative effects of drought stress in sugarcane. Future studies should be performed to elucidate if T. asperellum should be reapplied to the sugarcane ratoons.

Respostas da aplicação foliar de glicina betaína em cana-de-açúcar submetida a estresse hídrico e reidratação / Responses of the leaf application of glycine betaine on sugarcane submitted to drought stress and rehydration

O crescimento das plantas de cana-de-açúcar é bastante reduzido devido à ocorrência de déficit hídrico, o que acaba afetando a produção. Diante disso, vem sendo utilizadas diferentes estratégias para atenuar condições de estresse, como a aplicação exógena de glicina betaína. Com este trabalho, objetivou-se avaliar a taxa de crescimento e a massa seca de cana-de-açúcar aplicada glicina betaína, e submetida adéficit hídrico e reidratação. O experimento foi realizado em casa de vegetação com seis tratamentos: G0I - plantas sem glicina betaína com irrigação adequada, G0E - plantas sem glicina betaína e estresse hídrico, G1I - plantas com uma aplicação de glicina betaína e irrigação adequada, G1E - plantas com umaaplicação de glicina betaína e estresse hídrico, G2I - plantas com duas aplicações de glicina betaína e irrigação adequada, G2E - plantas com duas aplicações de glicina betaína e estresse hídrico. Aos seis dias após o estresse as plantas foram reidratadas. As taxas relativas de crescimento das plantas de cana-de-açúcar reduziram com o estresse hídrico. No entanto, estas reduções foram minimizadas com a aplicação foliar de glicina betaína, principalmente, com a reidratação em que a taxa relativa de crescimento reduziu apenas 19 e 18,4%, respectivamente, em G1 e G2, enquanto em G0 a redução foi de 37,2%. A glicina betaína também minimizou as reduções na produção de massa seca total sob estresse hídrico, com reduções de 5,8 e 5,9% em G1 e G2, respectivamente, enquanto em G0 foi de 15,1%. A aplicação foliar de glicina betaína melhora a taxa relativa de crescimento de plantas de cana-de-açúcar sob estresse hídrico, sobretudo após a reidratação o que diminui os efeitos negativos do estresse sobre a produção de massa seca.(AU)

The growth of sugarcane plants is greatly reduced due to the occurrence of drought stress, which ultimately affects production. Therefore, different strategies have been used to attenuate stress conditions, such as the exogenous application of glycine betaine. The objective of this work was to evaluate the growth rate and dry mass of sugarcane that received a glycine betaine application and was submitted todrought stress and rehydration. The experiment was carried out in a greenhouse with six treatments: G0I - plants without glycine betaine with adequate irrigation, G0E - plants without glycine betaine and drought stress, G1I - plants with an application of glycine betaine and adequate irrigation, G1E - plants with an application of glycine betaine and drought stress, G2I - plants with two applications of glycine betaine and adequate irrigation, G2E - plants with two applications of glycine betaine and drought stress. Six days after the stress, the plants were rehydrated. The relative growth rates of sugarcane plants decreased with the drought stress. However, these reductions were partially minimized with the foliar application of glycine betaine, mainly with the rehydration, with the relative growth rate decreasing by only 19% and 18.4%, respectively, in G1 and G2, while the reduction was 37.2% in G0. Glycine betaine also minimized reductions in total dry mass production under drought stress, with decreases of 5.8% and 5.9% in G1 and G2, respectively, while it was 15.1% in G0. The leaf application of glycine betaine improves the relative growth rate of sugarcane plants under drought stress, especially after rehydration, which decreases the negative effects of stress on dry mass production.(AU)

Respostas da aplicação foliar de glicina betaína em cana-de-açúcar submetida a estresse hídrico e reidratação / Responses of the leaf application of glycine betaine on sugarcane submitted to drought stress and rehydration

O crescimento das plantas de cana-de-açúcar é bastante reduzido devido à ocorrência de déficit hídrico, o que acaba afetando a produção. Diante disso, vem sendo utilizadas diferentes estratégias para atenuar condições de estresse, como a aplicação exógena de glicina betaína. Com este trabalho, objetivou-se avaliar a taxa de crescimento e a massa seca de cana-de-açúcar aplicada glicina betaína, e submetida adéficit hídrico e reidratação. O experimento foi realizado em casa de vegetação com seis tratamentos: G0I - plantas sem glicina betaína com irrigação adequada, G0E - plantas sem glicina betaína e estresse hídrico, G1I - plantas com uma aplicação de glicina betaína e irrigação adequada, G1E - plantas com umaaplicação de glicina betaína e estresse hídrico, G2I - plantas com duas aplicações de glicina betaína e irrigação adequada, G2E - plantas com duas aplicações de glicina betaína e estresse hídrico. Aos seis dias após o estresse as plantas foram reidratadas. As taxas relativas de crescimento das plantas de cana-de-açúcar reduziram com o estresse hídrico. No entanto, estas reduções foram minimizadas com a aplicação foliar de glicina betaína, principalmente, com a reidratação em que a taxa relativa de crescimento reduziu apenas 19 e 18,4%, respectivamente, em G1 e G2, enquanto em G0 a redução foi de 37,2%. A glicina betaína também minimizou as reduções na produção de massa seca total sob estresse hídrico, com reduções de 5,8 e 5,9% em G1 e G2, respectivamente, enquanto em G0 foi de 15,1%. A aplicação foliar de glicina betaína melhora a taxa relativa de crescimento de plantas de cana-de-açúcar sob estresse hídrico, sobretudo após a reidratação o que diminui os efeitos negativos do estresse sobre a produção de massa seca.

The growth of sugarcane plants is greatly reduced due to the occurrence of drought stress, which ultimately affects production. Therefore, different strategies have been used to attenuate stress conditions, such as the exogenous application of glycine betaine. The objective of this work was to evaluate the growth rate and dry mass of sugarcane that received a glycine betaine application and was submitted todrought stress and rehydration. The experiment was carried out in a greenhouse with six treatments: G0I - plants without glycine betaine with adequate irrigation, G0E - plants without glycine betaine and drought stress, G1I - plants with an application of glycine betaine and adequate irrigation, G1E - plants with an application of glycine betaine and drought stress, G2I - plants with two applications of glycine betaine and adequate irrigation, G2E - plants with two applications of glycine betaine and drought stress. Six days after the stress, the plants were rehydrated. The relative growth rates of sugarcane plants decreased with the drought stress. However, these reductions were partially minimized with the foliar application of glycine betaine, mainly with the rehydration, with the relative growth rate decreasing by only 19% and 18.4%, respectively, in G1 and G2, while the reduction was 37.2% in G0. Glycine betaine also minimized reductions in total dry mass production under drought stress, with decreases of 5.8% and 5.9% in G1 and G2, respectively, while it was 15.1% in G0. The leaf application of glycine betaine improves the relative growth rate of sugarcane plants under drought stress, especially after rehydration, which decreases the negative effects of stress on dry mass production.

Sugarcane production and climate trends in Paraíba state (Brazil).

Statistical surveys to detect trends in time series are fundamental tools to evaluate farming dynamics of sugarcane and of adaptation plans for possible impacts caused by climate change. This work analyzed the influence of climate change in the cultivation of sugarcane in the state of Paraíba (Northeast Brazil), in order to investigate what are the consequences of temperature increase, air humidity level, and changes in the precipitation regime forecasted for the region in sugarcane farming. Data of temperature, total precipitation, and relative humidity of six meteorological stations kept by the Brazilian National Institute of Meteorology (INMET) spread across the state of Paraíba and data from the area of sugarcane harvesting from the Brazilian Institute of Geography and Statistics (IBGE). Mann-Kendall trend test was employed in order to analyze the existence of trends in each station, separately. The results pointed trends of significant increase in temperature for the stations of Campina Grande, João Pessoa, Monteiro, Patos, and Sousa. The stations of Areia, Campina Grande, and João Pessoa obtained significant precipitation trends. Regarding relative humidity, the stations of João Pessoa, Monteiro, and Patos presented significant decreasing trends, while Sousa showed significant increase trends. The results suggest that these trends may be increasing sugarcane production close to the coast of the region and decreasing production inland.

Nitrogênio e Azospirillum brasilense no desenvolvimento inicial da cana-de-açúcar / Nitrogen and Azospirillum brasilense in the initial development of sugarcane

Um estudo foi conduzido com o objetivo de avaliar os efeitos da interação entre a inoculação da muda pré-brotada com Azospirillum brasilense e a adubação nitrogenada em cobertura no desenvolvimentodas plantas de cana-de-açúcar(Saccharum officinarum). Mudas pré-brotadas de cana-de-açúcar, oriundas de minirrebolos de 3,0cm de comprimento da variedade RB867515, foram transplantadas aos 25 dias após a brotação para vasos plásticos de 12 L. Os tratamentos foram dispostos em um delineamento de blocos casualizados, em esquema fatorial 2 × 5:dois tratamentos de inoculação [sem (controle) e com inoculação de Azospirillum brasilense] e cinco doses de adubação nitrogenada em cobertura (0, 30, 60, 90 e 120 mg dm–3de N), com quatro repetições. A inoculação com A. brasilense foi realizada no transplantio das mudas com o uso de 4 mL do inoculante AzoTotal®por muda, contendo as estirpes AbV5e AbV6. A adubação nitrogenada em cobertura foi realizada aos 20 dias após o transplantio das mudas na forma de ureia (45% de N).Os resultados reportaram que a aplicação de doses de N em coberturaresultou no incremento linear da altura de planta, diâmetro de colmo, número de folhas por planta, número de perfilhos e produção de matéria seca das plantas inoculadas com A. brasilense. Quando as plantas não foram inoculadas com A. brasilense, a adubação nitrogenada resultou apenas no aumento do número de folhas e de perfilhos por planta. O uso da inoculação de A. brasilenseem mudas de cana-de-açúcar pré-brotadas tem efeito benéfico no desenvolvimento das plantas somente quando associada a adubação nitrogenada em cobertura. As plantas de cana-de-açúcar não adubadas com fertilizante nitrogenado tem resposta negativa à inoculação com A. brasilense, indicando a ocorrência de possíveis efeitos fitotóxicos no desenvolvimento das plantas até os 60 dias após o transplantio.(AU)

A study was conducted with the objective of investigating the effects of the interaction between the inoculation of the pre-sprouted seedlings with Azospirillum brasilenseand the nitrogen fertilization in topdressing on the development of sugarcane plants(Saccharum officinarum). Pre-sprouted sugarcane seedlings, produced from 3.0 cm long mini-stems of the RB867515 variety, were transplanted 25 days after sprouting into 12 L plastic pots. The treatments were arranged in a randomized block design, in a 2 × 5 factorial scheme: two inoculation treatments [without (control) and inoculation with Azospirillum brasilense] and five application rates of N fertilizer in topdressing (0, 30, 60, 90 and 120 mg dm–3of N), with four repetitions. The inoculation with A. brasilense was carried out in transplanting the seedlings using 4 mL of the inoculum AzoTotal® per seedling, containing the strains AbV5 and AbV6. The nitrogen fertilization in topdressing was performed at 20 days after transplanting the seedlings as urea (45% of N). The results reported that the application of N fertilizer rates in topdressing resulted in a linear increase in plant height, stem diameter, number of leaves per plant, number of tillers and dry matter production of plants inoculated with A. brasilense. When the plants were not inoculated with A. brasilense, nitrogen fertilization resulted in an increase also in the number of leaves and tillers per plant. The use of A. brasilense inoculation in pre-sprouted sugarcane seedlings has a beneficial effect on the development of plants only when associated with nitrogen fertilization in topdressing. Sugarcane plants not fertilized with N have a negative response to inoculation with A. brasilense, indicating the occurrence of possible phytotoxic effects on plant development up to 60 days after transplanting.(AU)

Nitrogênio e Azospirillum brasilense no desenvolvimento inicial da cana-de-açúcar / Nitrogen and Azospirillum brasilense in the initial development of sugarcane

Um estudo foi conduzido com o objetivo de avaliar os efeitos da interação entre a inoculação da muda pré-brotada com Azospirillum brasilense e a adubação nitrogenada em cobertura no desenvolvimentodas plantas de cana-de-açúcar(Saccharum officinarum). Mudas pré-brotadas de cana-de-açúcar, oriundas de minirrebolos de 3,0cm de comprimento da variedade RB867515, foram transplantadas aos 25 dias após a brotação para vasos plásticos de 12 L. Os tratamentos foram dispostos em um delineamento de blocos casualizados, em esquema fatorial 2 × 5:dois tratamentos de inoculação [sem (controle) e com inoculação de Azospirillum brasilense] e cinco doses de adubação nitrogenada em cobertura (0, 30, 60, 90 e 120 mg dm–3de N), com quatro repetições. A inoculação com A. brasilense foi realizada no transplantio das mudas com o uso de 4 mL do inoculante AzoTotal®por muda, contendo as estirpes AbV5e AbV6. A adubação nitrogenada em cobertura foi realizada aos 20 dias após o transplantio das mudas na forma de ureia (45% de N).Os resultados reportaram que a aplicação de doses de N em coberturaresultou no incremento linear da altura de planta, diâmetro de colmo, número de folhas por planta, número de perfilhos e produção de matéria seca das plantas inoculadas com A. brasilense. Quando as plantas não foram inoculadas com A. brasilense, a adubação nitrogenada resultou apenas no aumento do número de folhas e de perfilhos por planta. O uso da inoculação de A. brasilenseem mudas de cana-de-açúcar pré-brotadas tem efeito benéfico no desenvolvimento das plantas somente quando associada a adubação nitrogenada em cobertura. As plantas de cana-de-açúcar não adubadas com fertilizante nitrogenado tem resposta negativa à inoculação com A. brasilense, indicando a ocorrência de possíveis efeitos fitotóxicos no desenvolvimento das plantas até os 60 dias após o transplantio.

A study was conducted with the objective of investigating the effects of the interaction between the inoculation of the pre-sprouted seedlings with Azospirillum brasilenseand the nitrogen fertilization in topdressing on the development of sugarcane plants(Saccharum officinarum). Pre-sprouted sugarcane seedlings, produced from 3.0 cm long mini-stems of the RB867515 variety, were transplanted 25 days after sprouting into 12 L plastic pots. The treatments were arranged in a randomized block design, in a 2 × 5 factorial scheme: two inoculation treatments [without (control) and inoculation with Azospirillum brasilense] and five application rates of N fertilizer in topdressing (0, 30, 60, 90 and 120 mg dm–3of N), with four repetitions. The inoculation with A. brasilense was carried out in transplanting the seedlings using 4 mL of the inoculum AzoTotal® per seedling, containing the strains AbV5 and AbV6. The nitrogen fertilization in topdressing was performed at 20 days after transplanting the seedlings as urea (45% of N). The results reported that the application of N fertilizer rates in topdressing resulted in a linear increase in plant height, stem diameter, number of leaves per plant, number of tillers and dry matter production of plants inoculated with A. brasilense. When the plants were not inoculated with A. brasilense, nitrogen fertilization resulted in an increase also in the number of leaves and tillers per plant. The use of A. brasilense inoculation in pre-sprouted sugarcane seedlings has a beneficial effect on the development of plants only when associated with nitrogen fertilization in topdressing. Sugarcane plants not fertilized with N have a negative response to inoculation with A. brasilense, indicating the occurrence of possible phytotoxic effects on plant development up to 60 days after transplanting.