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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.

RESUMO

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.

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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.

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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.

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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.

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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.

RESUMO

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.

RESUMO

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.

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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.

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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)

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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.

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BACKGROUND: Sugarcane silage has been increasing as a feed in the tropics by dairy farmers. However, sugarcane normally had high yeast population that leads to intense alcoholic fermentation and excessive Dry-Matter (DM) loss during ensilage and after air exposure, as well. There are several patents that have recently shown the benefits of applying Lactobacillus buchneri in forage preservation. OBJECTIVE: This study aimed to investigate the changes in pH, DM, Water-Soluble Carbohydrates (WSC) and fermentation end product concentrations that occur in sugarcane silage with or without inoculation with L. buchneri after 45 days of ensiling. METHODS: Sugarcane plants were harvested with approximately 16 months of growth and chopped at 2 cm. Four strains of wild L. buchneri (56.1, 56.4, 56.9 and 56.26) and the commercial inoculant "Lalsil Cana" were evaluated. For all treatments, the theoretical application rate was 1.0 × 106 colony- forming units (cfu) per g of fresh weight. Data from the silo openings were analysed as a completely randomized design, with four replicates per treatment (inoculants). RESULTS: The treatment with L. buchneri affected the DM content, pH, Lactic Acid Bacteria (LAB) population, DM recovery, and concentrations of WSC, lactic acid, acetic acid and ethanol of sugarcane silage after 45 days of ensiling. Yeasts and molds populations and the concentrations of propionic and butyric acids were not affected by the treatments. CONCLUSION: Lactobacillus buchneri 56.1 and 56.4 are considered the most suitable strains for improving the fermentation of sugarcane silage and thus are potential inoculants for silage production. At present, we are preparing the patent application.

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The sugarcane borer, Diatraea saccharalis (Fabr., 1794) (Lepidoptera: Crambidae), is one of the main pests of sugarcane. This pest can reduce the quality and yield of the crop. Information on the quality and yield of cultivars in relation to the attack of sugarcane borer are necessary, since they guide the choice of the best materials for use in joint with other management tactics. Two field experiments were conducted in 2011 and 2012 to compare the quality and yield of 16 commercial sugarcane cultivars (IACSP93-3046, IACSP94-2094, IACSP94-2101, IAC91-1099, IACSP95-5000, IAC87-3396, RB92579, RB867515, RB966928, CTC2, CTC4, CTC9, CTC11, CTC15, CTC18 and SP86-0042) relative to the natural infestation of D. saccharalis. The experimental design was a randomized complete block with four replications. There was no difference between treatments for infestation index, with averages of 1.2 to 8.7% of bored internodes. Higher percentages of internodes with red rot were observed for CTC9, CTC2 and RB966928. The cultivars CTC4 and RB92579 infested with D. saccharalis resulted in lower technological quality, due the reduction in the contents of brix, apparent sucrose content (POL) and purity; and increase of the reducing sugars and, consequently, lower theoretically recoverable sugar (TRS). On the other hand, the lowest yields (t of cane ha-1) were observed for CTC18, IACSP94-2094, IACSP94-2101 and RB966928. Therefore, according to the hierarchical cluster analysis (UPGMA), the cultivars RB867515, CTC11, IAC91-1099, CTC15, SP86-0042, CTC2 and IACSP94-3046 were resistant to D. saccharalis.(AU)

A broca-da-cana, Diatraea saccharalis (Fabr., 1794) (Lepidoptera: Crambidae), é uma das principais pragas da cana-de-açúcar. Essa praga pode reduzir a qualidade e a produtividade da cultura. Informações sobre a qualidade e a produtividade de cultivares em relação ao ataque da broca-da-cana são necessárias, pois orientam a escolha dos melhores materiais para utilização em conjunto com outras táticas de manejo. Dois experimentos de campo foram instalados em 2011 e 2012 para comparar a qualidade e a produtividade de 16 cultivares comerciais de cana-de-açúcar (IACSP93-3046, IACSP94-2094, IACSP94-2101, IAC91-1099, IACSP95-5000, IAC87-3396, RB92579, RB867515, RB966928, CTC2, CTC4, CTC9, CTC11, CTC15, CTC18 e SP86-0042) em relação à infestação natural de D. saccharalis. O delineamento dos experimentos foi em blocos completos ao acaso, com quatro repetições. Não houve diferença entre os tratamentos para a intensidade de infestação, com médias de 1,2 a 8,7% de entrenós brocados. Maiores porcentagens de entrenós com podridão-vermelha foram observadas para CTC9, CTC2 e RB966928. Os cultivares CTC4 e RB92579 infestados com D. saccharalis resultaram em menor qualidade tecnológica, por causa da redução nos teores de brix, teor de sacarose aparente (POL) e pureza; e aumento dos açúcares redutores e, consequentemente, menor quantidade de açúcar teoricamente recuperável (ATR). Por outro lado, as menores produtividades (t de cana ha-1) foram observadas para CTC18, IACSP94-2094, IACSP94-2101 e RB966928. Portanto, de acordo com a análise hierárquica de agrupamento (UPGMA), os cultivares RB867515, CTC11, IAC91-1099, CTC15, SP86-0042, CTC2 e IACSP94-3046 mostraram-se resistentes a D. saccharalis.(AU)

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The sugarcane borer, Diatraea saccharalis (Fabr., 1794) (Lepidoptera: Crambidae), is one of the main pests of sugarcane. This pest can reduce the quality and yield of the crop. Information on the quality and yield of cultivars in relation to the attack of sugarcane borer are necessary, since they guide the choice of the best materials for use in joint with other management tactics. Two field experiments were conducted in 2011 and 2012 to compare the quality and yield of 16 commercial sugarcane cultivars (IACSP93-3046, IACSP94-2094, IACSP94-2101, IAC91-1099, IACSP95-5000, IAC87-3396, RB92579, RB867515, RB966928, CTC2, CTC4, CTC9, CTC11, CTC15, CTC18 and SP86-0042) relative to the natural infestation of D. saccharalis. The experimental design was a randomized complete block with four replications. There was no difference between treatments for infestation index, with averages of 1.2 to 8.7% of bored internodes. Higher percentages of internodes with red rot were observed for CTC9, CTC2 and RB966928. The cultivars CTC4 and RB92579 infested with D. saccharalis resulted in lower technological quality, due the reduction in the contents of brix, apparent sucrose content (POL) and purity; and increase of the reducing sugars and, consequently, lower theoretically recoverable sugar (TRS). On the other hand, the lowest yields (t of cane ha-1) were observed for CTC18, IACSP94-2094, IACSP94-2101 and RB966928. Therefore, according to the hierarchical cluster analysis (UPGMA), the cultivars RB867515, CTC11, IAC91-1099, CTC15, SP86-0042, CTC2 and IACSP94-3046 were resistant to D. saccharalis.(AU)

A broca-da-cana, Diatraea saccharalis (Fabr., 1794) (Lepidoptera: Crambidae), é uma das principais pragas da cana-de-açúcar. Essa praga pode reduzir a qualidade e a produtividade da cultura. Informações sobre a qualidade e a produtividade de cultivares em relação ao ataque da broca-da-cana são necessárias, pois orientam a escolha dos melhores materiais para utilização em conjunto com outras táticas de manejo. Dois experimentos de campo foram instalados em 2011 e 2012 para comparar a qualidade e a produtividade de 16 cultivares comerciais de cana-de-açúcar (IACSP93-3046, IACSP94-2094, IACSP94-2101, IAC91-1099, IACSP95-5000, IAC87-3396, RB92579, RB867515, RB966928, CTC2, CTC4, CTC9, CTC11, CTC15, CTC18 e SP86-0042) em relação à infestação natural de D. saccharalis. O delineamento dos experimentos foi em blocos completos ao acaso, com quatro repetições. Não houve diferença entre os tratamentos para a intensidade de infestação, com médias de 1,2 a 8,7% de entrenós brocados. Maiores porcentagens de entrenós com podridão-vermelha foram observadas para CTC9, CTC2 e RB966928. Os cultivares CTC4 e RB92579 infestados com D. saccharalis resultaram em menor qualidade tecnológica, por causa da redução nos teores de brix, teor de sacarose aparente (POL) e pureza; e aumento dos açúcares redutores e, consequentemente, menor quantidade de açúcar teoricamente recuperável (ATR). Por outro lado, as menores produtividades (t de cana ha-1) foram observadas para CTC18, IACSP94-2094, IACSP94-2101 e RB966928. Portanto, de acordo com a análise hierárquica de agrupamento (UPGMA), os cultivares RB867515, CTC11, IAC91-1099, CTC15, SP86-0042, CTC2 e IACSP94-3046 mostraram-se resistentes a D. saccharalis.(AU)

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RESUMO

ABSTRACT Although there are evidences that the proper supply of mineral nutrients to plants relieves water stress, little is known on the approach of how the drought affects the absorption and accumulation of nutrients by distinct sugar cane genotypes, or in different parts of a same plant. Thus, the objective of this study was to determine the content and accumulation of N, P and K in the aerial part of plant from three genotypes of sugar cane, submitted to three water potentials in the soil, and check the relationship of these variables with the tolerance of plants to prolonged drought. In order to access this objective, an experiment under greenhouse conditions, comprised by a fatorial 3 × 3, in a randomized block design, and four replicates was carried out. After 90 days from treatment imposition, the plant transpiration rate, plant dry mass, concentration of N, P and K were determined in leaves and culms, as well as in total plant shoot were measured. It was found that tolerance to drought in sugar cane is related to higher levels of N and K in the leaves and stems, and larger accumulations of K and P in the plant shoot. There is high positive correlations among accumulation of N, P and K in the plant shoot and dry matter production by plants submitted to drought. There are intermediate correlations among plant transpiration and nutrient uptake by plants under drought. Plants of the genotype SP81-3250 are more tolerante to prolonged drought, than the RB855453 and IACSP95-5000 plants.

RESUMO Embora existam evidências de que o adequado fornecimento de nutrientes minerais para plantas alivia o estresse hídrico, pouco se sabe sobre a abordagem de como a seca afeta a absorção e acumulação de nutrientes por distintos genótipos de cana-de-açúcar, ou por diferentes partes de uma mesma planta. Assim, o objetivo deste estudo foi determinar o teor e acúmulo de N, P e K na parte aérea da planta de três genótipos de cana-de-açúcar, submetidos a três potenciais hídricos do solo e verificar se existe relação dessas variáveis ​​com a tolerância das plantas ao déficit hídrico prolongado. Para isso, foi realizado um experimento em casa de vegetação, em um esquema fatorial 3×3, em delineamento de blocos casualizados, com quatro repetições. Após 90 dias da imposição dos tratamentos, foi determinada a massa seca e a taxa de transpiração das plantas, a concentração de N, P e K nas folhas e colmos, além do acúmulo desses nutrientes na parte aérea das plantas. Verificou-se que a tolerância à seca em cana está relacionada com níveis mais altos de N e K nas folhas e caules e maiores acumulações de K e P na parte aérea das plantas. Existem fortes correlações positivas entre acúmulo de N, P e K na parte aérea das plantas e produção de matéria seca. Existem correlações intermediárias entre a transpiração da planta e absorção de nutrientes pelas plantas sob seca. Plantas do genótipo SP81-3250 são mais tolerantes à seca prolongada, que as plantas RB855453 e IACSP95-5000.

RESUMO

This experiment evaluated the correlation between the estimates of fecal digestibility and dry matter digestibility (DMD) and nutrients obtained using internal (indigestibles dry materiDM, neutral detergent fiber-iNDF, acid detergent fiber-iADF and acid detergent ligniniADL) and external (chromium oxide-Cr2O3, titanium dioxide-TiO2, and purified and enriched lignin from eucalyptus-LIPE®) markers and the values obtained by the total feces collection method. Twenty uncastrated male sheep, with 29.64±5.53 kg average live weight; approximately 12 months old, were kept in metabolic cages and fed diets containing untreated sugarcane-top hay or sugarcane-top hay hydrolyzed with 3 and 6% urea or 1.5 and 3% calcium oxide (CaO). There was a positive correlation (P<.05) between the fecal production estimated by the markers and via total feces collection, with coefficients higher than 90% for iDM, Cr2O3, and TiO2. The DMD and nutrients estimated with the use of markers was positively correlated (P<.05) with that obtained by total feces collection. Coefficients of correlation for digestibility obtained by total collection were higher than those obtained with Cr2O3, but close to those obtained using TiO2. The coefficient of correlation between the digestibility of protein and fiber fraction estimated with iDM and iNDF and that obtained by total collection was higher than 70%. Internal marker iDM and external markers Cr2O3 and TiO2 are effective in estimating fecal production and DMD and nutrients.(AU)

Avaliou-se a correlação das estimativas de produção fecal e digestibilidade da matéria seca (DMS) e nutrientes obtidas por indicadores internos (matéria seca-MSi, fibra em detergente neutro-FDNi, fibra em detergente ácido-FDAi e lignina em detergente ácido-LDAi indigestíveis) e externos (óxido de cromo-Cr2O3, dióxido de titânio-TiO2 e lignina purificada e enriquecida de eucalipto-LIPE®) com valores obtidos pelo método de coleta total de fezes. Utilizaram-se 20 ovinos, machos, não castrados, com 29,64 ± 5,53 kg de peso vivo médio e aos 12 meses de idade, mantidos em gaiolas metabólicas e alimentados com rações compostas por feno de ponta de cana-de-açúcar não tratado ou hidrolisado com 3 e 6% de ureia ou 1,5 e 3% de óxido de cálcio (CaO). Houve correlação positiva (P<0,05) da produção fecal estimada pelos indicadores com a coleta total de fezes, com coeficientes maiores de 90% para MSi, Cr2O3 e TiO2. A digestibilidade da MS e de nutrientes estimada a partir do uso de indicadores correlacionou-se positivamente com a obtida pela coleta total de fezes. Maiores coeficientes de correlação foram obtidos para a digestibilidade por coleta total em relação ao Cr2O3, com valores aproximados aos obtidos para TiO2. Quanto aos indicadores internos MSi e FDNi, a digestibilidade da proteína e fração fibrosa apresentou coeficiente de correlação com a digestibilidade por coleta total superior a 70%. O indicador interno MSi e os externos Cr2O3 e TiO2 são eficazes na estimativa da produção fecal e digestibilidade da MS e nutrientes.(AU)

Assuntos

RESUMO

This experiment evaluated the correlation between the estimates of fecal digestibility and dry matter digestibility (DMD) and nutrients obtained using internal (indigestibles dry materiDM, neutral detergent fiber-iNDF, acid detergent fiber-iADF and acid detergent ligniniADL) and external (chromium oxide-Cr2O3, titanium dioxide-TiO2, and purified and enriched lignin from eucalyptus-LIPE®) markers and the values obtained by the total feces collection method. Twenty uncastrated male sheep, with 29.64±5.53 kg average live weight; approximately 12 months old, were kept in metabolic cages and fed diets containing untreated sugarcane-top hay or sugarcane-top hay hydrolyzed with 3 and 6% urea or 1.5 and 3% calcium oxide (CaO). There was a positive correlation (P<.05) between the fecal production estimated by the markers and via total feces collection, with coefficients higher than 90% for iDM, Cr2O3, and TiO2. The DMD and nutrients estimated with the use of markers was positively correlated (P<.05) with that obtained by total feces collection. Coefficients of correlation for digestibility obtained by total collection were higher than those obtained with Cr2O3, but close to those obtained using TiO2. The coefficient of correlation between the digestibility of protein and fiber fraction estimated with iDM and iNDF and that obtained by total collection was higher than 70%. Internal marker iDM and external markers Cr2O3 and TiO2 are effective in estimating fecal production and DMD and nutrients.

Avaliou-se a correlação das estimativas de produção fecal e digestibilidade da matéria seca (DMS) e nutrientes obtidas por indicadores internos (matéria seca-MSi, fibra em detergente neutro-FDNi, fibra em detergente ácido-FDAi e lignina em detergente ácido-LDAi indigestíveis) e externos (óxido de cromo-Cr2O3, dióxido de titânio-TiO2 e lignina purificada e enriquecida de eucalipto-LIPE®) com valores obtidos pelo método de coleta total de fezes. Utilizaram-se 20 ovinos, machos, não castrados, com 29,64 ± 5,53 kg de peso vivo médio e aos 12 meses de idade, mantidos em gaiolas metabólicas e alimentados com rações compostas por feno de ponta de cana-de-açúcar não tratado ou hidrolisado com 3 e 6% de ureia ou 1,5 e 3% de óxido de cálcio (CaO). Houve correlação positiva (P<0,05) da produção fecal estimada pelos indicadores com a coleta total de fezes, com coeficientes maiores de 90% para MSi, Cr2O3 e TiO2. A digestibilidade da MS e de nutrientes estimada a partir do uso de indicadores correlacionou-se positivamente com a obtida pela coleta total de fezes. Maiores coeficientes de correlação foram obtidos para a digestibilidade por coleta total em relação ao Cr2O3, com valores aproximados aos obtidos para TiO2. Quanto aos indicadores internos MSi e FDNi, a digestibilidade da proteína e fração fibrosa apresentou coeficiente de correlação com a digestibilidade por coleta total superior a 70%. O indicador interno MSi e os externos Cr2O3 e TiO2 são eficazes na estimativa da produção fecal e digestibilidade da MS e nutrientes.

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RESUMO

The widespread usage of commercial varieties of sugar that are adapted to agricultural system and come from parents with a small genetic distance can lead to a narrowing of the genetic basis of sugarcane. This study aimed to induce mutations and evaluate the genetic distance among the sugarcane mutants produced by different multivariate techniques. Were induced mutations and then evaluate the genetic distance among these sugarcane mutants with the use of multivariate techniques. The study was conducted in the experimental area of the UFSM, Frederico Westphalen - RS. The genotype used for mutation induction was IAC 873396. The induction process proceeded with the placement of buds in a solution of the mutagenic agent MMS (Methyl Methane Sulfonate). A total of 22 mutants and six commercial checks were evaluated for 12 traits of agronomic interest. The analyses were: the evaluation of individual averages, Tocher"s grouping, average Euclidean distance, an analysis of principal components, and the relative contribution of characteristics. The mutation induction process generated significant patterns of genetic variability among sugarcane mutants verified by three multivariate analyses. The UPGMA clustering methods, Tocher and principal component analysis revealed similar results related to the dissimilarity of sugarcane genotypes. Genotypes 20, 24, and 10 were greater than the general average of genotypes and have a high genetic dissimilarity for traits. The yield of stems, bagasse mass, and the yield sugarcane broth are sufficient to characterize a set of sugarcane genotypes.(AU)

O uso generalizado de variedades comerciais adaptadas ao sistema agrícola, oriundas de genitores muito próximos, com pequena distância genética pode levar ao estreitamento da base genética em cana-de-açúcar. O trabalho teve por objetivo induzir mutação e avaliar a distância genética entre os mutantes produzidos de cana-de-açúcar, por diferentes técnicas multivariadas, almejando a identificação de mutantes com caracteres contrastantes, com interesse para o melhoramento de cana-de-açúcar no Sul do Brasil. O trabalho foi desenvolvido na área experimental da Universidade Federal de Santa Maria, Campus de Frederico Westphalen, RS. O genótipo utilizado para indução de mutação foi o IAC 873396. O processo de indução transcorreu com a alocação de gemas em solução do agente mutagênico MMS. Foram avaliados 22 mutantes e seis testemunhas comerciais para 12 caracteres de interesse agronômico. As análises realizadas foram: avaliação das médias dos indivíduos, agrupamento de Tocher, distância euclidiana média, análise de componentes principais e a contribuição relativa dos caracteres. O processo de indução de mutação gerou padrões significativos de variabilidade genética entre os mutantes de cana-de-açúcar verificada pelas três análises multivariadas. Os métodos de agrupamento UPGMA, Tocher e a análise de componentes principais revelam resultados próximos quanto à dissimilaridade dos genótipos de cana-de-açúcar. Os genótipos 20, 24 e 10 são superiores a média geral dos genótipos e apresentam elevada dissimilaridade genética. O rendimento do colmo, massa do bagaço e rendimento de caldo são caracteres suficientes para realizar a discriminação do conjunto de genótipos de cana-de-açúcar.(AU)

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RESUMO

The aim of this work was to evaluate the development and quality of sugarcane variety RB 867515 and chemical attributes of the soil in response to the application of increasing level of fertilization. It was used randomized blocks design, with five treatments (0, 3, 6, 9 and 12 t/ha of poultry litter) and four replications. At four months after planting there were no differences among poultry liter levels on plant height, culm diameter, and leaves width and length, but the number of plants/m linear and number of leaves/plant reached maximum values using 8.7 and 5.3 t/ha of poultry litter, respectively. At 12 months after planting, there was increase in P, K, Ca and Mg by increasing the level of fertilization with poultry litter and linear increase in productivity of sugarcane green mass. Therefore, up to 12 t/ha of poultry litter can be applied to maximize the performance of sugarcane and improve soil fertility. In addition to the reached productivity, the accumulation of soluble sugar (mean 20 degrees Brix), as well as contents of dry matter (32.9%) and neutral detergent fiber (46.7%) indicates that the sugarcane variety RB 867515, of mean/late cycle, presents appropriate for the first cut for animal feeding at 12 months after planting.(AU)

Objetivou-se com este trabalho avaliar o desenvolvimento e a qualidade da cana-deaçúcar variedade RB 867515 e os atributos químicos do solo em resposta à aplicação de níveis variáveis de fertilização. Utilizou-se o delineamento experimental em blocos casualizados, com cinco tratamentos (0, 3, 6, 9 e 12t/ha de cama de frango) e quatro repetições. Aos quatro meses pós-plantio não houveram diferenças entre os níveis de cama de frango sobre a altura das plantas, diâmetro do colmo, largura da folha e comprimento da folha, mas o número de plantas/m linear e número de folhas/planta atingiram valores máximos utilizando 8,7 e 5,3 t/ha de cama de frango, respectivamente. Aos 12 meses após o plantio foram observados aumentos de P, K, Ca e Mg pelo incremento no nível de fertilização com cama de frango e aumento linear na produtividade de massa verde da cana. Portanto, pode-se aplicar até 12 t/ha de cama de frango para maximizar o desempenho da cultura e melhorar a fertilidade do solo. Além da produtividade alcançada, o acúmulo de açúcar solúvel (média de 20 graus Brix), bem como os teores de matéria seca (32,9%) e fibra em detergente neutro (46,7%) indicam que a cana variedade RB 867515, de ciclo médio/tardio, já se apresenta apropriada para o primeiro corte para alimentação animal aos 12 meses pósplantio.(AU)

Assuntos

RESUMO

The aim of this work was to evaluate the development and quality of sugarcane variety RB 867515 and chemical attributes of the soil in response to the application of increasing level of fertilization. It was used randomized blocks design, with five treatments (0, 3, 6, 9 and 12 t/ha of poultry litter) and four replications. At four months after planting there were no differences among poultry liter levels on plant height, culm diameter, and leaves width and length, but the number of plants/m linear and number of leaves/plant reached maximum values using 8.7 and 5.3 t/ha of poultry litter, respectively. At 12 months after planting, there was increase in P, K, Ca and Mg by increasing the level of fertilization with poultry litter and linear increase in productivity of sugarcane green mass. Therefore, up to 12 t/ha of poultry litter can be applied to maximize the performance of sugarcane and improve soil fertility. In addition to the reached productivity, the accumulation of soluble sugar (mean 20 degrees Brix), as well as contents of dry matter (32.9%) and neutral detergent fiber (46.7%) indicates that the sugarcane variety RB 867515, of mean/late cycle, presents appropriate for the first cut for animal feeding at 12 months after planting.

Objetivou-se com este trabalho avaliar o desenvolvimento e a qualidade da cana-deaçúcar variedade RB 867515 e os atributos químicos do solo em resposta à aplicação de níveis variáveis de fertilização. Utilizou-se o delineamento experimental em blocos casualizados, com cinco tratamentos (0, 3, 6, 9 e 12t/ha de cama de frango) e quatro repetições. Aos quatro meses pós-plantio não houveram diferenças entre os níveis de cama de frango sobre a altura das plantas, diâmetro do colmo, largura da folha e comprimento da folha, mas o número de plantas/m linear e número de folhas/planta atingiram valores máximos utilizando 8,7 e 5,3 t/ha de cama de frango, respectivamente. Aos 12 meses após o plantio foram observados aumentos de P, K, Ca e Mg pelo incremento no nível de fertilização com cama de frango e aumento linear na produtividade de massa verde da cana. Portanto, pode-se aplicar até 12 t/ha de cama de frango para maximizar o desempenho da cultura e melhorar a fertilidade do solo. Além da produtividade alcançada, o acúmulo de açúcar solúvel (média de 20 graus Brix), bem como os teores de matéria seca (32,9%) e fibra em detergente neutro (46,7%) indicam que a cana variedade RB 867515, de ciclo médio/tardio, já se apresenta apropriada para o primeiro corte para alimentação animal aos 12 meses pósplantio.

Assuntos