1,602 research outputs found

    Pastagens para ovinos.

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    Espécies forrageiras mais indicadas; Sistema de pastejo; Sistema de pastejo com lotação contínua; Sistema de lotação rotacionada; Com um grupo de animais; Com dois grupos de animais; Creep grazing; Diferido ou protelado; Manejo e lotação da pastagem; Estacionalidade de produção de forragem

    Recurrence of multiple meiotic abnormalities in maize genotypes from the same origin and their influence on productivity.

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    The frequency of meiotic abnormalities among single-, double- and three-way cross experimental hybrids and their parental inbred lines is studied. Among the sixteen inbred lines examined, fifteen originated from populations developed at the National Center of Research in Maize and Sorghum (CNPMS/Embrapa) and one from a population developed at ESALQ (Faculty of Agriculture Luiz de Queiroz of the University of São Paulo). Previous analyses of homozygous and heterozygous maize genotypes from CNPMS populations demonstrated high meiotic instability. The present investigation aims at analyzing the meiotic behavior of different inbred lines obtained from CNPMS populations by another breeding enterprise to verify the presence of the same abnormalities and determine whether the abnormalities might compromise productivity. Analyses showed the presence of some abnormalities described previously, albeit at a lower frequency. The most common abnormalities in homozygous and heterozygous genotypes from CNPMS populations were related to irregular chromosome segregation and to chromosome stickiness. An inbred line from the ESALQ population showed only abnormalities related to irregular chromosome segregation caused by the presence of univalent chromosomes. The Pearson correlation procedure indicated high negative correlation between meiotic abnormalities and productivity

    Recurrence of multiple meiotic abnormalities in maize genotypes from the same origin and their influence on productivity.

    Get PDF
    The frequency of meiotic abnormalities among single-, double- and three-way cross experimental hybrids and their parental inbred lines is studied. Among the sixteen inbred lines examined, fifteen originated from populations developed at the National Center of Research in Maize and Sorghum (CNPMS/Embrapa) and one from a population developed at ESALQ (Faculty of Agriculture Luiz de Queiroz of the University of São Paulo). Previous analyses of homozygous and heterozygous maize genotypes from CNPMS populations demonstrated high meiotic instability. The present investigation aims at analyzing the meiotic behavior of different inbred lines obtained from CNPMS populations by another breeding enterprise to verify the presence of the same abnormalities and determine whether the abnormalities might compromise productivity. Analyses showed the presence of some abnormalities described previously, albeit at a lower frequency. The most common abnormalities in homozygous and heterozygous genotypes from CNPMS populations were related to irregular chromosome segregation and to chromosome stickiness. An inbred line from the ESALQ population showed only abnormalities related to irregular chromosome segregation caused by the presence of univalent chromosomes. The Pearson correlation procedure indicated high negative correlation between meiotic abnormalities and productivity

    Unidades de observação de híbridos de milho, em dois espaçamentos entre linhas, na Região de Clima Temperado ? Safra. 2009/10.

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    A seleção de critérios no zoneamento agroecológico: proposta metodológica.

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    A seleção de critérios espaciais para um trabalho de zoneamento agroecológico envolve critérios de aptidão, biodiversidade, socioeconomia, recursos hídricos, legais, ambientais, políticas etc. É necessário identificar a questão-chave e traçar diretrizes do zoneamento que representem as orientações do setor. Essas diretrizes são econômicas, estratégicas, empresariais, sociais, técnicas e políticas, obtidas em negociação com representantes de diferentes setores da sociedade e, ao fim, ponderar os diversos critérios segundo a importância de cada um, no contexto em análise. Este trabalho tem por objetivo apresentar uma metodologia de identificação coletiva desses critérios com o aporte de recursos de sistemas de suporte à decisão espacial e de planejamento estratégico territorial. A metodologia apresenta as seguintes etapas: diagnóstico estratégico, identificação de critérios determinantes (não ponderáveis), identificação dos critérios a serem ponderados e uma proposta de fluxo de procedimentos para a seleção de critérios espaciais. Visa subsidiar a formulação de políticas públicas de ordenamento territorial do setor rural. O resultado é composto de um conjunto de procedimentos e de uma lista de perguntas-chave para compor os diagnósticos e selecionar os critérios espaciais que podem ser aplicados em trabalhos de planejamento territorial adicionado a visão estratégica

    High conversion of palm olein to ethyl esters using a strong anion exchange resin: study of the operational parameters

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    Biodiesel, known as a mixture of fatty acid ethyl/methyl esters, is seen as an alternative, ecofriendly, biodegradable and renewable non-fossil fuel. The use of heterogeneous catalysts for biodiesel synthesis can solve several problems associated with the homogeneous alkaline catalyzed-transesterification. Therefore, this work reports the evaluation of the commercial resin Amberlyst A26OH, a strong anion exchange resin, as a heterogeneous catalyst for the batch transesterification of refined palm olein with ethanol. It was studied the effects of the main operational parameters, considering the molar ratio of the reaction mixture (MRRM), namely the molar ratio of ethanol to olein taking into account only the ethanol added to the reaction system, and the total molar ratio (TMR), in this case considering also the amount of ethanol carried by the resin after its pretreatment. It was determined an optimal range of operational conditions by response surface methodology, guaranteeing conversion to ethyl esters higher than 96% with a catalyst amount corresponding to a range from 10.4 to 11.4% of the oil quantity, a temperature within the range of 55 to 60 ºC and a MRRM within the range from 3.5:1 to 6.0:131714011412CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP406963/2016-9; 406856/2013-3; 429873/2018-2; 305870/2014-9Sem informação2014/21252-0; 2016/10636-
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