3,306 research outputs found

    Produtividade de leguminosas em sistema agroflorestal.

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    O experimento foi conduzido para avaliar a produtividade de leguminosas de sub-bosque em sistema agroflorestal. Foi adotado um esquema de parcelas subdivididas no espaço, no delineamento em blocos casualizados com três repetições. A parcela principal foi o espaçamento do eucalipto e a subparcela espécies de leguminosas. Foram encontradas diferenças de produtividade de MS do subbosque em função do espaçamento de plantio com 100 dias de rebrota das leguminosas e não foram encontradas diferenças de produtividade entre leguminosas de sub-bosque. O maior valor de produtividade (5.984 kg de MS/ha) de leguminosas para sub-bosque foi obtido no espaçamento 12x3. As produtividades das leguminosas estilosantes, calopogônio e amendoim foram, respectivamente, de 5.031; 2.923 e 5.494 kg de MS/ha. Os resultados encontrados são importantes para escolher tanto o espaçamento de plantio de eucalipto como a espécie de sub-bosque em sistemas agroflorestais no Cerrado brasileiro. Productivity of legumes in agroforestry system. Abstract: The work was carried out to evaluate the productivity of understory?s legumes in agroforestry system. A split plot arrangement, with three replicates in the randomized block design, was utilized. Main plot was eucalyptus spacing and sub-plots legumes species. Differences were found to productivity of understory in function of planting spacing with 100 days of regrowth of legumes and there was not difference of productivity between understory?s legumes. The highest productivity (5,984 kg of DM/ha) of legumes to understory was found in 12x3 spacing. The yields of legumes Stylosanthes, Calopogonium and Arachis were respectively 5,031; 2,923 and 5,494 kg of DM/ha. Results found are important to choose as planting spacing to eucalyptus as specie of understory in agroforestry system in Brazilian Cerrado

    Fontes de resistência de videira ao fungo oídio no Nordeste brasileiro.

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    Foram avaliadas 135 variedades distintas em três ciclos, observando-se as mesmas plantas sem nenhum oídicida

    Box-Behnken Design for optimization of Fenton-type reaction for water treatment using heterogeneous catalysts

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    Response Surface Methodology (RSM) was widely used in numerous research works for the optimization of different processes for liquid effluents treatment, since water pollution is one of the most serious environmental problem concerning human health and sustainability.1,2 RSM is a statistical technique applied to reduce the number of experiments, optimize and analyze the experimental independent parameters, that affect a process efficiency, and to generate a mathematical model which describes the process behavior.1,3 In this work, Box-Behnken design (BBD) was used for optimize the Fenton-type reaction using different bimetallic catalysts based in Rare Earth Elements with iron ion exchanged in zeolite (NaY) or a natural clay from Morocco. The effect of different experimental parameters such as, temperature, concentration of H2O2 and the heterogeneous catalysis used, was studied and optimized.We thank the Fundação para a Ciência e Tecnologia for financial support through Centre of Chemistry (UID/QUI/00686/2013 and UID/QUI/0686/2016) and BioTecNorte (operation NORTE-01-0145-FEDER-000004)info:eu-repo/semantics/publishedVersio

    Relevance of additive and non-additive genetic relatedness for genomic prediction in rice population under recurrent selection breeding

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    In genomic recurrent selection programs of self-pollinated crops, additive genetic effects (breeding values) are effectively relevant for selection of superior progenies as new parents. However, considering additive and nonadditive genetic effects can improve the prediction of genome-enhanced breeding values (GEBV) of progenies, for quantitative traits. In this study, we assessed the magnitude of additive and nonadditive genetic variances for eight key traits in a rice population under recurrent selection, using marker-based relationship matrices. We then assessed the goodness-to-fit, bias, stability and accuracy of prediction for breeding values and total (additive plus nonadditive) genetic values, in five genomic best linear unbiased prediction (GBLUP) models, ignoring or not nonadditive genetic effects. The models were compared using 6174 single nucleotide polymorphisms (SNP) markers from 174 S1:3 progenies evaluated in field yield trial. We found dominance effects accounting for a substantial proportion of the total genetic variance for the key traits in rice, especially for days to flowering. In average of the traits, the component of variance additive, dominance, and epistatic contributed to about 34%, 14% and 9% for phenotypic variance. Additive genomic models, ignoring nonadditive genetic effects, showed better fit to the data and lower bias, in addition to greater stability and accuracy for predict GEBV of progenies. These results improve our understanding of the genetic architecture of the key traits in rice, evaluated in early-generation testing. Clearly, this study highlighted the advantages of additive models using genome-wide information, for genomic prediction applied to recurrent selection in a self-pollinated crop

    Sensory analysis as a tool to support rice breeding research: a comparison between hybrid rice and conventional commercial rice.

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    This study aims to assess sensory differences between a hybrid variety sample and conventional commercial rice samples by the Difference from Control Method. This method provides information on the size of the difference between a control and other sample

    Wood characterization using the power spectral density and phase velocity of ultrasonic signals.

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    The application of non-destructive testing (NDT) in the analysis of trees in forest plantations permits the evaluation of the wood quality, the internal defects in development or pest attack and its characterization for application as solid wood and its products. These techniques have been constantly improved with the use of computers, electronics and agricultural control levels in order to provide tools to the specialists in integrated management. The ultrasound has been used in agriculture as NDT to determine the elasticity modulus of juvenile and mature wood of pinus and other species. This study aimed to the evaluation of new techniques for characterization of wood using parameters such as the power spectral density (PSD) and phase velocity of ultrasonic signals propagating in wood. The tests were performed using a pair of ultrasonic transducers with central frequency of 50 kHz (083-067-038, GE) which were connected to an ultrasonic pulser/receiver (5077PR, Olympus). The transmitting transducer was coupled to the samples of pinus using ultrasound gel and excited with negative pulses of short duration (5 μs) and high amplitude (-400 V) to generate longitudinal and shear waves. The ultrasound signals that propagated through the samples were received by the receiving transducer, amplified (20 to 40 dB), acquired in a digital scope (MSO4104B, Tektronix) and then transferred to a microcomputer. The tests have been done with 10 reference samples (healthy) and 10 attacked by wood wasps, with small holes in the bark. The transducers were placed on the samples in the axial, radial and inclined modes. The data were processed using the Matlab (Mathworks Inc.) to determine the power spectral density (PSD), the root mean square deviation index (cRMSDdB) and the phase velocity between the reference and attacked samples. The cRMSDdB calculated between the PSD of the reference and the attacked samples were generally higher for samples with higher degree of damage, however, in some cases, they were lower due to the presence of wood knots. The phase velocities were calculated in the frequency range 1-200 kHz and generally show higher values for the reference samples. The group velocities were also calculated and the results were in the range 1200-3000 m/s, indicating that these parameters can be used for wood characterization

    Análise da população de arqueas metanogenicas no lodo de reator UASB alimentado com dejetos de suínos utilizando a eletroforese em gel com gradiente desnaturante (DGGE).

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    Foi realizada a caracterização microbiana, por meio de técnicas de biologia molecular, do lodo anaeróbio de um reator UASB de volume 12 m3 alimentado com dejetos de suínos operado em condições mesofílicas com TDH médio de 72 h. Essa caracterização foi realizada no lodo ao longo do compartimento de digestão por meio de sete pontos eqüidistantes entre si em 0,40 cm (P1 mais próximo ao fundo a P7). A caracterização microbiana foi realizada por meio da técnica de reação em cadeia da polimerase (PCR) seguida de eletroforese em gel com gradiente desnaturante (DGGE). Posteriormente serão feitos o sequenciamento e análise filogenética com o objetivo de identificar os grupos de microrganismos predominantes nas amostras. Até o momento observou-se a presença de cinco grupos de bandas de Archae em todos os perfis, sendo que o número de bandas totais encontrados nos perfis das amostras decresce à medida que se aumenta o nível na coluna do reator. Também foi constatada uma diversidade relativamente baixa de arqueas nas amostras de lodo, que pode está associada à estabilização do ambiente no reator

    Avaliação das perdas minerais provocadas pelo polimento do arroz (Oryza sativa L.).

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    Esse trabalho tem como objetivo quantificar as perdas nutricionais em relação às concentrações de Fe, Zn, Cu e Mn em oito genótipos de arroz não comerciais submetidos ao beneficiamento convencional da sua forma integral
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