bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcário e escória de siderurgia avaliados por análise foliar, acúmulo, e exportação de macronutrientes em cana-de-açúcar
Authors: Prado Renato de Mello , Fernandes Francisco Maximino , Natale William
Published: April 2005

A opção de uso de materiais corretivos alternativos como as escórias de siderurgia, pode influenciar na absorção de nutrientes pela planta e, consequentemente, na diagnose foliar, acúmulo e exportação de nutrientes. Com o objetivo de estudar o efeito da aplicação de doses de escória de siderurgia e de calcário na absorção de macronutrientes pela cana-de-açúcar (variedade SP80-1842), foi instalado em janeiro de 1998, em Ituverava-SP, um experimento de campo. Aplicou-se escória de siderurgia e calcário, em quatro doses equivalentes 0; 1,23; 2,52 e 3,80 t ha-1 de CaCO3, em um Latossolo Vermelho-Amarelo distrófico, em pré-plantio na cana-planta. Determinaram-se, além da produção de colmos, as concentrações de macronutrientes na folha +3 da cana-planta e da cana-soca (aos 120 dias após a emergência dos brotos) e na parte aérea da cana-soca (aos 345 dias após a emergência dos brotos). Os materiais corretivos e as doses não alteraram a absorção de macronutrientes pela cana-de-açúcar. Houve maior acúmulo e exportação de macronutrientes de acordo com as doses de ambos corretivos. A escória de siderurgia comportou-se de modo semelhante ao calcário na nutrição da cana-de-açúcar quanto aos macronutrientes.
Suscetibilidade de Oligonychus yothersi (Acari: Tetranychidae) ao fungo Beauveria bassiana
Authors: Oliveira Renato Cassol de , Alves Luis Francisco Angeli , Neves Pedro Manuel Oliveira Janeiro
Published: April 2005

A cultura da erva-mate (Ilex paraguariensis) é uma importante atividade econômica no Sul do Brasil. Com o aumento de consumo nos anos oitenta, cresceram também as áreas de monocultura, gerando condições favoráveis para o aumento populacional de insetos e ácaros fitófagos, entre eles o ácaro vermelho Oligonychus yothersi. Este estudo avaliou a suscetibilidade do ácaro vermelho O. yothersi a vários isolados do fungo Beauveria bassiana. O experimento foi conduzido em Cascavel, PR. Discos foliares de erva-mate (2,2 cm²) foram previamente infestados com 20 fêmeas adultas. Alíquotas de 1 mL de cada suspensão de conídios dos diferentes isolados de B. bassiana, ajustadas na concentração de 1,0x10(8) conídios mL-1 foram pulverizadas, separadamente, sobre um conjunto de 5 discos. Os discos foliares foram mantidos flutuando em água destilada, em caixas plásticas (3 cm de diâmetro), sob condições controladas. Diariamente, os ácaros mortos foram transferidos para câmara úmida, para confirmação de mortalidade causada pelo fungo. A mortalidade total variou entre 77 e 98% (6 dias após a aplicação), não permitindo diferenciar os isolados quanto à virulência (P>0,05). Já a mortalidade confirmada variou entre 19 e 75%, permitindo diferenciá-los (P<0,05). O ácaro vermelho O. yothersi foi suscetível, em diferentes níveis, aos isolados de B. bassiana testados.
Degradabilidade do capim-elefante em diferentes estágios de maturidade avaliada pelo método in vitro/gás
Authors: Campos Fábio Prudêncio de , Lanna Dante Pazzanese Duarte , Bose Max Lázaro Vieira , Boin Celso , Sarmento Patrícia
Published: April 2005

O capim-elefante (Pennisetum purpureum Schum.) é uma gramínea tropical de elevada capacidade de acumulação de matéria seca, mas seu valor nutritivo é acentuadamente influenciado pela maturidade. Considerando a natureza intrínseca da parede celular nas diferentes partes da planta, o conhecimento de suas taxas e extensões de degradação permite a determinação de qual componente e qual estágio de maturidade que afeta sua digestão. Portanto, o objetivo deste trabalho foi avaliar a degradabilidade da matéria seca (MS) do capim-elefante cv. Napier, pelo método in vitro/gás, com cortes de 45 a 105 dias a intervalos de 10 dias entre os cortes. Notou-se decréscimo na degradabilidade das frações do capim-elefante com o avanço do estágio de maturidade. Os coeficientes de regressão da degradabilidade da MS estimados pelo resíduo remanescente da digestão para folhas e hastes foram 0,51 e 0,89, respectivamente. Para degradabilidade da fibra em detergente neutro (FDN) os coeficientes de regressão para folhas e hastes foram 0,82 e 0,92, respectivamente. Na produção total de gás os coeficientes de regressão para folhas foi de 0,56 e 0,90 para hastes. Em geral, a haste do capim-elefante, com o avanço da maturidade vegetativa, apresentou maior influência no decréscimo da degradabilidade da MS e da FDN que as folhas. O avanço no estágio de maturidade do capim-elefante afeta diretamente a degradabilidade das hastes e das folhas. Isto é mais acentuado para hastes devido a elevada lignificação da parede celular.
Amadurecimento e senescência de mamão com 1-metilciclopropeno
Authors: Jacomino Angelo Pedro , Kluge Ricardo Alfredo , Brackmann Auri , Castro Paulo Roberto de Camargo e
Published: April 2005

O mamão (Carica papaya L.) é uma fruta altamente perecível devido ao rápido amadurecimento após a colheita. A busca de técnicas que ampliem o período de conservação e reduzam as perdas pós-colheita é desejável. Mamões 'Sunrise Solo' foram colhidos em dois estádios de maturação (verde e maduro) e tratados com o antagonista competitivo do etileno 1-metilciclopropeno (1-MCP) nas concentrações de 0, 30, 90 e 270 nL L-1, durante 12 horas a 20ºC. Após o tratamentos os frutos foram armazenados em condições ambientais (20ºC) durante oito dias. A aplicação do 1-MCP (90 e 270 nL L-1) retardou a perda de coloração verde dos frutos e a incidência de podridões. Frutos verdes tratados com 1-MCP (270 nL L-1) apresentaram maior firmeza do que os frutos controle. O 1-MCP não afetou o conteúdo de sólidos solúveis dos frutos. A taxa respiratória e a produção de etileno foram reduzidas nos frutos tratados com 1-MCP (90 nL L-1 e 270 nL L-1) em ambos estádios de maturação. O 1-MCP (90 nL L-1 e 270 nL L-1) aumentou a vida de prateleira dos frutos do estádio verde de quatro para seis dias e dos frutos maduros de dois para quatro dias. Este bloqueador da ação do etileno mostrou-se eficiente para retardar o amadurecimento de mamões e aumentar sua vida de prateleira
Lime and gypsum application on the wheat crop
Authors: Caires Eduardo Fávero , Feldhaus Itacir Cesar , Barth Gabriel , Garbuio Fernando José
Published: April 2005

Root growth and crop yield can be affected by chemical modifications of the soil profile owing to lime and gypsum applications. A field trial was carried out on a dystrophic Clayey Rhodic Hapludox at Ponta Grossa, PR, Brazil, aiming to evaluate lime (without or with incorporation into the soil) and gypsum effects on root growth, mineral nutrition and grain yield of wheat (cv. OR 1). A randomized complete block design was used, with three replications, in a split-plot experiment. Treatments with dolomitic limestone (without lime and 4.5 t ha-1 of lime applied on the surface, in total rate and 1/3 of the requirement per year during 3 years, or incorporated into the soil) were applied in July 1998 (main plots) and the rates of gypsum (0, 3, 6 and 9 t ha-1) in October 1998 (subplots). Wheat was evaluated in the 2000 winter season. In conditions of water deficit absence, there was no limitation in root growth in depth, for exchangeable Ca of 6 mmol c dm-3. Lime incorporation of lime increased the Mg concentration in the leaves, but wheat yield was not influenced by the correction of soil acidity through liming treatments. Gypsum increased the concentrations of Ca and S in wheat leaves, with significant effects on grain yield. The critical level of S-SO4(2-) in the 0-20 cm soil layer, extracted by ammonium acetate 0.5 mol L-1 in acetic acid 0.25 mol L-1, was 25.8 mg dm-3.
Reference evapotranspiration based on class A pan evaporation
Authors: Conceição Marco Antônio Fonseca
Published: April 2005

Estimating reference evapotranspiration (ETo) based on Class A pan evaporation (ECA) is very usual in irrigated areas. For this purpose the ECA values are multiplied by a pan coefficient (Kp) to obtain ETo. Kp values can be estimated in different ways being, however, important to know which method would estimate the best value for a given locality. In the present work estimated values of ETo based on Class A pan evaporation, using Kp values determined by different methods, were compared to Penman-Monteith-FAO (EToPM) values for the northwest region of the São Paulo State, Brazil. The annual average Kp, determined dividing EToPM by ECA, was 0.74. For the rainy months (December to March) the average Kp value was 0.80 and for the dry months (April to November) 0.70. The reference evapotranspiration estimated using Kp determined by the Snyder equation presented the best regression coefficients when compared to EToPM.
Produtividade do Panicum maximum cv. Mombaça irrigado, sob pastejo rotacionado
Authors: Müller Marcela dos Santos , Fancelli Antonio Luiz , Dourado-Neto Durval , García y García Axel , López Ovejero Ramiro Fernando
Published: April 2005

O uso da irrigação em pastagens é uma realidade fundamentada na experiência empírica de produtores, devido à falta de bases científicas definidas sobre o assunto. O trabalho visou avaliar a produtividade do capim Mombaça (Panicum maximum Jacq. cv. Mombaça) manejado em pastejo rotacionado, sob sistema de irrigação e as principais variáveis climáticas responsáveis pelo acúmulo de massa de forragem. O experimento foi conduzido sob irrigação por aspersão tipo pivô central, de julho a dezembro de 1998, em região de cerrado (Latossolo Vermelho-Amarelo) em São Desidério, BA. Foi quantificada a massa de forragem da pastagem aos 30 dias de crescimento e antes do pastejo e desenvolvidos modelos matemáticos que relacionam a produção de forragem a variáveis climáticas. A produção e a taxa de acúmulo de matéria seca da pastagem, ao longo do período de inverno não apresentaram diferenças significativas. Na primavera, houve tendência de aumento em ambas, com maiores produções obtidas no período final de avaliação. As menores taxas de acúmulo durante a primavera foram observadas nos primeiros piquetes, coincidindo com a ocorrência de baixas temperaturas durante o período de descanso. Com a elevação da temperatura mínima, a produção forrageira entrou em fase de acúmulo crescente. A produção de forragem, durante a primavera, foi superior à do inverno, apresentando incrementos em função da maior temperatura mínima do ar, do período de descanso e da área foliar inicial. As principais variáveis climáticas responsáveis pela produção da forragem foram temperatura mínima do ar e disponibilidade de água no solo.
Income-elasticity of poultry meat consumption in metropolitan areas of Brazil
Authors: Bacchi Miriam Rumenos Piedade , Spolador Humberto Francisco Silva
Published: April 2005

Studies on the meat market behavior may result in interesting parameters for the market and public policy agents. The definition of the income-elasticity of poultry consumption enables the elaboration of prospective analysis on the potential demand of this product. Thus, the main objective of the present study is to estimate the income-elasticities of poultry consumption. Data from the 1995-96 and 1987-88 Consumer Expenditure Survey, published by IBGE (Brazilian Institute of Geography and Statistics), were used in the analysis. The elasticities were obtained by fitting a three-segment polygonal curve relating the logarithm of the per capita poultry meat consumption as a function of the per capita family income. Generalized Least Squares method was used for the econometric model fitting. The elasticities were obtained considering the total, carcasses and selected individual poultry parts consumption. Average income elasticity of the total consumption enables the classification of poultry meat as a normal product. The observed average income elasticities showed that breast and thighs are superior products. In the last period, a negative elasticity was observed for carcasses.
Atividade de buprofezin sobre a cigarrinha verde do feijoeiro Empoasca kraemeri (Ross & Moore, 1957) (Hemiptera, Cicadellidae) em condições de laboratório
Authors: Moreno Paulo Rogério , Nakano Octávio
Published: April 2005

A espécie Empoasca kraemeri é uma importante praga para a cultura do feijoeiro (Phaseolus vulgaris L.) em toda a América Latina, sendo necessário recorrer ao controle químico quando a praga atinge alta população. Neste trabalho, foi estudado o efeito do inseticida buprofezin sobre ninfas de primeiro instar de Empoasca kraemeri (Hemiptera, Cicadellidae), sob condições de laboratório. Esta fase da praga mostrou-se altamente susceptível ao inseticida, sendo a CL50 estimada de 0,112 mg L-1. Em outro bioensaio, casais virgens e recém-emergidos foram colocados em contato com plantas de feijoeiro previamente imersas na calda do inseticida. A longevidade média para fêmeas/machos foi de: 46/27, 18/16 e 16/14 dias para a testemunha, 10 e 50 mg L-1 de buprofezin, respectivamente. Observou-se uma média de 102; 0,9 e 0,1 ovos por fêmea no tratamento testemunha, 10 e 50 mg L-1 de buprofezin, respectivamente. O ritmo de postura, que determina a longevidade dos indivíduos, foi de 2,31; 0,09 e 0,01 ovos/fêmea/dia para a testemunha, 10 e 50 mg L-1 de buprofezin, respectivamente. No último bioensaio, foi investigado o efeito de buprofezin sobre os adultos, porém, tratando-se apenas fêmeas e machos isoladamente com o inseticida em superfície contaminada a 1000 mg L-1 de buprofezin e posteriormente, colocando-os junto a insetos do sexo oposto que não haviam sido contaminados. Foi observada longevidade para fêmeas/machos de: 46/27, 35/23 e 27/13 dias para o tratamento testemunha, fêmeas tratadas e machos tratados, respectivamente. O ritmo de postura não apresentou diferença, sendo de 2,31; 2,56 e 2,42 ovos/fêmea/dia no tratamento testemunha, fêmeas tratadas e machos tratados, respectivamente.
Produção e qualidade de folhas de amoreira em função da época do ano e de colheita
Authors: Miranda José Ednilson , Bonacin Gisele Aparecida , Takahashi Roque
Published: April 2005

A quantidade e qualidade das folhas de amoreira (Morus alba L.) exercem influência marcante sobre o desenvolvimento do bicho-da-seda e são, por sua vez, influenciadas por fatores como a idade das folhas, época do ano e características genéticas dos cultivares. Avaliou-se a produção e a qualidade nutricional de folhas de cinco cultivares de amoreira em diferentes épocas do ano e de colheita, objetivando verificar sua adaptação na região de Jaboticabal (SP). As folhas dos cultivares 'Miura', 'Korin', 'Calabresa', 'FM86' e 'FM Shima-Miura' foram colhidas na primavera, verão e outono após 45, 60, 75 e 90 dias da poda (DAP) e avaliadas quanto à produção de folhas níveis de proteína bruta (PB) e fibra em detergente neutro (FDN). As melhores produções foram verificadas em 'FM Shima-Miura', principalmente aos 75 DAP na primavera e no verão e aos 90 DAP no outono. No verão, as colheitas efetuadas aos 60, 75 e 90 DAP resultaram em produções mais elevadas. As épocas de colheita que resultaram em maiores níveis de PB foram aos 45 e 60 DAP e em menores níveis de FDN aos 60 DAP, respectivamente. Foi possível conciliar altos níveis de PB, baixos níveis de FDN e relativamente alta produção de massa foliar somente na colheita efetuada aos 75 DAP.
Isoenzymatic variability of cassava accessions from different regions in Brazil
Authors: Cabral Betânia Lúcia Rocha , Souza Joelson Araújo de , Ando Akihiko , Veasey Elizabeth Ann , Cardoso Eloisa Maria Ramos
Published: April 2005

Cassava (Manihot esculenta Crantz) belongs to the Euphorbiaceae family, and is widely cultivated in Brazil. The objective of this study was to evaluate the isoenzymatic variability of 200 cassava accessions from the germplasm bank of Embrapa Amazonia Oriental. Seven groups were formed according to their origin: 1-Amazonas, 2-Amapa, 3-Bahia, 4-Para, 5-Rondonia, 6-Various, for accessions with a maximum of three individuals per place of origin, and 7 - Accessions of indefinite origin. The accessions were also evaluated as a whole. For the electrophoretic analyses, samples of young leaves were used in a 12% starch gel. Eight isoenzymatic systems were evaluated: acid phosphatase (ACP), leucine aminopeptidase (LAP), glucose-6-phosphate dehydrogenase (G6PDH), malate dehydrogenase (MDH), shikimate dehydrogenase (SKDH), malic enzyme (ME), glutamate dehydrogenase (GTDH) and isocitrate dehydrogenase (IDH). Analysis revealed a polymorphic locus for each system and high isoenzymatic variability among accessions. The average number of alleles per locus varied from 2.3 to 2.5. Average observed heterozigosity varied from 0.381 to 0.615 and the diversity index varied from 0.479 to 0.559. Genetic variability within groups was greater than among groups, suggesting a distribution pattern similar to what can be expected for natural populations of outcrossing plants.
Adição de Zn e absorção, translocação e utilização de Zn e P por cultivares de cafeeiro
Authors: Reis Jr. Roberto dos Anjos , Martinez Hermínia E. P.
Published: April 2005

A crescente exigência de nutrientes, especialmente micronutrientes, pelos cultivares de café vem exigindo uma melhor compreensão da dinâmica desses nutrientes no sistema solo-planta. Com o objetivo de avaliar o efeito de concentrações de Zn (0,4 ; 1,3 e 2,3 mimol Zn L-1) na solução nutritiva sobre o crescimento, produção de matéria seca, eficiência de absorção, translocação e utilização de Zn e P em dois cultivares de café (Coffea arabica cv. Catuaí e Coffea canephora cv. Conilon), foi realizado um experimento sob delineamento inteiramente casualizado com esquema fatorial 3 × 2 (três doses de Zn e dois cultivares) com três repetições. Plantas de café dos dois cultivares estudados foram cultivadas em casa de vegetação, com solução nutritiva completa por 50 dias, após os quais receberam solução nutritiva modificada com três doses de Zn. Aos 114 dias após a transferência para a solução nutritiva modificada, as plantas foram coletadas e separadas em folhas superiores, inferiores, caule e raízes. Foram avaliadas altura do caule, número de ramificações laterais, área foliar, produção de matéria seca e conteúdos de P e Zn nas diversas partes da planta, além das eficiências de absorção, translocação e utilização de P e Zn. A dose 2,3 mimol Zn L-1 proporcionou os maiores valores para as características de crescimento avaliadas, tanto para o cultivar Catuaí, quanto para Conilon. Os maiores conteúdos de Zn observados no Catuaí indicam que este é mais exigente em Zn que o Conilon na fase de mudas. O Conilon apresentou menores eficiências de absorção e translocação e maior eficiência de utilização de Zn, refletindo sua menor demanda por este nutriente. As concentrações de Zn empregadas neste experimento não promoveram interação Zn-P.
Produção de amônia anidra e aquamônia enriquecida em 15N a partir de (15NH4)2SO4
Authors: Bendassolli José Albertino , Trivelin Paulo Cesar Ocheuze , Ignoto Raquel de Fátima
Published: April 2005

No Brasil, a aquamônia vem sendo utilizada como fertilizante nitrogenado, especialmente na cultura de cana de açúcar. Entre os fatores que influenciam a produtividade das culturas agrícolas, está a eficiência de utilização de fertilizantes nitrogenados (EUF), sendo a técnica isotópica com 15N empregada em investigações dessa natureza. Este trabalho procurou estabelecer métodos de produção de amônia anidra (15NH3) e aquosa (15NH3aq), enriquecidas em 15N, em um único sistema, a partir do sulfato de amônio previamente enriquecido no mesmo isótopo. O processo de produção de 15NH3 e 15NH3aq foi avaliado em função dos fatores: temperatura (60, 70 e 75ºC) e tempo de reação (90, 120, 150, 165, 210 e 255 minutos), fluxo de gás de arraste (140; 180 e 220 mL min-1 de N2) e massa de sulfato de amônio utilizada na reação (40; 72,6; 106; 132 e 200 g). As melhores condições com relação à produção de 15NH3 e 15NH3aq foram proporcionadas pela temperatura de 70ºC, fluxo de gás de arraste de 180 mL min-1 de N2 e tempo de reação de 210 minutos. O teor de N na 15NH3aq variou de 15 a 20% (m/m) e o sistema apresentou capacidade de produção de aproximadamente 280 mL de 15NH3aq com concentração de 15% (m/m) por batelada. O processo global apresentou rendimento na faixa de 91 a 99%, em função da massa de (15NH4)2SO4 utilizada, sendo as perdas de 15N desprezíveis.
Conceitos sobre solos coesos e hardsetting
Authors: Giarola Neyde Fabíola Balarezo , Silva Alvaro Pires da
Published: April 2005

Diferenças marcantes entre os graus de consistência do solo seco e úmido foram incorporadas ao sistema brasileiro de classificação de solos por meio da utilização do termo "coeso", o qual caracteriza solos que, quando secos, apresentam um incremento acentuado de resistência à penetração, e uma sensível redução dessa resistência, quando úmidos. Esse comportamento foi observado, há muito tempo, em solos da Austrália, tendo sido originalmente incorporado ao sistema australiano de classificação como "hardsetting". O objetivo deste trabalho foi mostrar as similaridades entre solos coesos e "hardsetting", com o entendimento de que essa conexão será útil nas pesquisas com solos coesos no Brasil.
Genetic divergence among elephantgrass cultivars assessed by RAPD markers in composit samples
Authors: Daher Rogério Figueiredo , Pereira Messias Gonzaga , Pereira Antônio Vander , Amaral Jr. Antônio Teixeira do
Published: April 2005

Elephantgrass (Pennisetum purpureum Schum.) is native to regions of tropical Africa and was introduced in Brazil around 1920 through plantings imported from Cuba. It is currently one of the most widespread forage plants throughout the country. At first, there were two cultivars, Napier and Mercker, with well defined characteristics. New genotypes arose and it is believed that the large number of cultivars existing today in germplasm bank is due to duplicates. DNA markers for cultivar characterization are a very valuable tool, especially in situations where morphological and isoenzymatic markers have already been used as in the case of elephantgrass. Thus RAPD markers were used to estimate the genetic divergence among the Napier group elephantgrass cultivars from the elephantgrass Active Germplasm Bank at EMBRAPA Dairy Cattle. The polymerase chain reaction with 37 arbitrary primers from the OPERON Technologies series supplied 94 polymorphic and 73 monomorphic bands. From the matrix of complement of the Nei index, cluster analysis by the Tocher optimization method formed three clusters. Pearson correlation among genetic distance estimates obtained from the DNA markers and the isoenzymatic markers showed the consistency of both the methods in assessing genetic divergence among elephantgrass cultivars. No duplicates were found in the treatments assessed.
Fluidodinâmica de sementes de brócolos em leito fluizado e leito de jorro
Authors: Almeida Celina de , Rocha Sandra Cristina dos Santos
Published: April 2005

Os processos em leito fluidizado e de jorro são comumente empregados para secagem, recobrimento e granulação de sistemas particulados nas indústrias química e farmacêutica, enquanto na área agronômica estão limitados a tratamento de algumas espécies de sementes. Este trabalho objetivou apresentar a análise fluidodinâmica dos leitos fluidizado e de jorro, quando são utilizadas sementes de brócolos (Brassica oleracea L. var. Italica) e verificar a influência na germinação das sementes, submetidas aos dois tipos de processo por 60 min à temperatura do ar de 25°C. A fluidodinâmica nos dois tipos de contato, leitos fluidizado e de jorro, foi estabelecida pelas medidas da queda de pressão no leito e vazões de ar crescentes e decrescentes, para diferentes cargas de sementes. As condições experimentais foram baseadas nas análises das propriedades físicas das sementes e limitadas às dimensões do equipamento de laboratório. O leito cone-cilíndrico foi projetado e construído em acrílico, para permitir a visualização do processo. Os valores de queda de pressão máxima, vazão de jorro mínimo, vazão de jorro estável e queda de pressão no mínimo jorro foram obtidos a partir dos gráficos de queda de pressão-vazão para o leito de jorro. Estes valores foram comparados aos correspondentes valores obtidos por equações empíricas citadas na literatura. O mesmo procedimento foi realizado para o leito fluidizado obtendo-se os valores para velocidade de mínima fluidização e queda de pressão na mínima fluidização. Não houve danos à germinação das sementes que participaram dos processos.
Development of Bemisia tabaci (Gennadius,1889) biotype B on Lycopersicon spp. genotypes
Authors: Marilene Fancelli , Vendramim José Djair
Published: April 2005

Whiteflies are phytophagous insects, whose nymphs and adults suck the phloem sap, causing direct damage due to host plant weakness. In tomato (Lycopersicon spp.) crops, they are important vectors of limiting fitoviruses. The objective of this study was to determine the effects of Lycopersicon spp. genotypes on Bemisia tabaci (Gennadius, 1889) biotype B development under greenhouse conditions. The evaluated genotypes were LA462 (L. peruvianum), LA716 (L. pennellii), LA1584 (L. pimpinellifolium), LA1609 (L. peruvianum), LA1739 (L. hirsutum), P25 (L. esculentum), PI134417 (L. hirsutum f. glabratum) and Santa Clara (L. esculentum). LA716 was non-preferred for oviposition by the whitefly, which suggests an antixenotic effect. LA1584 showed an antibiotic resistance because nymphal survival was reduced and nymphal developmental time was increased. Antixenotic resistance was observed in LA1739 and PI134417, based on a reduction of oviposition. PI134417 also reduced nymphal survival, which suggests an antibiotic effect, but LA1739 was suitable for insect development. LA1609 was highly preferred for oviposition, however it reduced insect survival. P25 and Santa Clara (L. esculentum) were highly preferred for oviposition.
Extração e dosagem da atividade da polifenoloxidase do café
Authors: Mazzafera Paulo , Gonçalves Kátia Viviane , Shimizu Milton Massao
Published: April 2005

A atividade de polifenoloxidase (PFO) tem sido usada como indicadora da qualidade de bebida de café. Foram feitas comparações entre o método tradicionalmente usado para extração de polifenoloxidase de café e outro, onde impediu-se a oxidação de fenóis durante a extração, com posterior eliminação por filtração em coluna de exclusão. Um método intermediário entre os dois também foi testado. As medições de atividade foram feitas por espectrofotometria e por consumo de O2. Os métodos tradicionais de extração e dosagem da atividade de PFO sofrem forte interferência de fenóis presentes no extrato, não permitindo reprodução dos dados publicados na literatura. Por espectrofotometria foi possível diferenciação apenas entre café de bebida Mole de cafés de bebida Dura e Rio, mas não entre as duas últimas. Café de melhor qualidade, bebida Mole, apresentou maior atividade de PFO. Extração de PFO na presença de antioxidantes e complexadores de fenóis, seguida pela eliminação dos mesmos por cromatografia de exclusão é essencial para uma avaliação correta. Entretanto, usando este procedimento e consumo de O2, a atividade de PFO também não diferenciou os três cafés testados, exceto o Mole dos dois outros. No lugar de DOPA (3,4 - dihidroxifenilalanina), usado comumente nas dosagens por espectrofotometria, sugere-se o emprego de ácido clorogênico (ácido 5-cafeoilquínico).
Estimating peach palm fruit surface area using allometric relationships
Authors: Bovi Marilene Leão Alves , Spiering Sandra Heiden
Published: April 2005

Fruit surface area is an important trait in studies of developmental physiology, as well as in entomological and phytopathological research, where damage caused by insects and/or microorganisms needs to be quantified. Nonetheless, direct measurement of this trait is difficult, not very precise and destructive. This study establishes allometric relationships to estimate the surface area of peach palm (Bactris gasipaes Kunth, Palmae) fruits. Five fruits were harvested, at different maturation stages, from each of 18 plants. Image digitalization and edition methodology was adapted and compared with the traditional gravimetric method. Regression analysis and curve fitting were used to compare the two methods and establish allometric relationships among fruit surface area and fruit weight and size. The method based on image digitalization was twice as fast as the gravimetric method. Curve fitting for all pairs of independent and dependent variables was better with the image method. For most relationships, the best model was the exponential function (Y = ax b), although, due to its simplicity, the linear model is also adequated. The best allometric estimates of fruit surface area (Y) were obtained using the product of fruit length by maximum width (x) were: Y = 2.077 x 1.189 (R² = 94.8%); and Y = - 6.261 + 3.961 x (R² = 94.5%). Traits needed to establish this relationship are easily measured and non-destructive in nature. Validation of the allometric equations is essential when applied to other populations or landraces.
Diallel crossing among maize populations for resistance to fall armyworm
Authors: Alvarez María del Pilar , Miranda Filho José Branco de
Published: April 2005

Among the insects infecting the maize (Zea mays L.) crop in Brazil, the fall armyworm (Spodoptera frugiperda Smith, 1797, Lepdoptera: Noctuidae) is considered one of the most important because it causes the highest damage to yield. Genetic resistance to the fall armyworm has be an effective control strategy. The main objective of this work was to evaluate new germplasm sources for resistance to the fall armyworm, the key pest for the maize crop in Brazil. A partial diallel design between 20 varieties of Brazilian germplasm and nine exotic and semi-exotic varieties of different origin was used. The 180 crosses and 29 parental varieties along with two commercial checks were evaluated in three locations in the State of São Paulo State (Brasil). Fall armyworm resistance (FAWR) under artificial and natural infestations, grain yield (GY), and plant height (PH) were analyzed. The populations CMS14C and MIRT, and hybrid São José x MIRT showed the highest resistance, with values of 1.8, 1.7 and 1.4, respectively. Populations PMI9401 and PR91B, and the hybrid CMS14C x (B97xITU) had best yields, with 4893, 3858 and 5677 kg ha-1, respectively. Heterosis ranged from -28% to 47% for FAWR and from -21% to 125% for GY, with mean values of -0,43% and 31%, respectively. Genotype by environment interaction was not significant for FAWR. The effects of varieties and heterosis were significant for all traits, showing that both additive and dominance effects may be important as sources of variation. For FAWR, only specific heterosis presented significance, suggesting strong genetic divergence between specific pairs of parental populations. Brasilian populations PMI9302 and São José, and the exotic population PR91B presented high performance per se, and also in croses for FAWR and GY. Crosses PMI9401 x (Cuba110 x EsalqPB1) and São José x MIRT presented high specific heterosis effects for both characters. These populations can be useful to be introgressed in maize breeding programs.
More adequate probability distributions to represent the saturated soil hydraulic conductivity
Authors: Mesquita Maria da Glória Bastos de Freitas , Moraes Sérgio Oliveira , Corrente José Eduardo
Published: April 2005

The saturated soil hydraulic conductivity (Ksat) is one of the most relevant variables in studies of water and solute movement in the soil. Its determination in the laboratory and in the field yields high dispersion results, which could be an indication that this variable has a no symmetrical distribution. Adjustment of the normal, lognormal, gamma and beta distributions were examined in order to search for a probability were density function that would more adequately describe the distribution of this variable. The experiment consisted in determining the saturated hydraulic conductivity, through the constant head permeameter method, in undisturbed samples of three soils of different textures from the central western region of the São Paulo State, Brazil, and submitting the results to the statistical tests for identification of the most adequate asymmetrical distribution to represent them. Ksat presented high variability, non normal distribution and lognormal, gamma and beta distributions fit. The lognormal probability density function was the most indicated to describe the variable, due to the verified greater agreement.
Degradation of caffeine by microorganisms and potential use of decaffeinated coffee husk and pulp in animal feeding
Authors: Mazzafera Paulo
Published: April 2005

Coffee husk and coffee pulp are coffee processing by-products. Coffee husk is obtained when harvested coffee is processed by the dry method, and coffee pulp is produced by the wet method. In Brazil, coffee is usually processed by the dry method, therefore an expressive amount of husk is obtained every year. Some of the husk is used as organic fertilizer but, other applications are very limited, mainly because it is a bulky product. The presence of tannins and caffeine diminish acceptability and palatability of husk by animals. This review discuss degradation of caffeine by microorganisms, with special attention to bacterial, biological decaffeination of coffee husk and pulp and its subsequent use on animal feeding. The known biochemical routes of caffeine degradation by microorganisms are initially discussed; problems concerning physiological effects in animals, focusing on the limitations imposed by caffeine as an antiphysiological component are raised; the use of microorganisms to decaffeinate coffee husk and pulp is discussed. The discussions offer a view on decreasing caffeine content of coffee husk and pulp, which would allow the use of larger amounts of these products in animal feeding, partially replacing traditional components such as cereal grains.
Start-up adjustment of a plug-flow digester for cassava wastewater (manipueira) treatment
Authors: Ribas Maria Magdalena Ferreira , Barana Ana Cláudia
Published: April 2005

Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic biodigestion. To study the start-up process of a plug-flow digester for manipueira treatment, this work consisted of two stages: gradual decrease of the hydraulic retention time (HRT) to the preset time of 4 days or maintaining a fixed HRT of 4 days with gradual increase of the substrate concentration. A digester of 1980 mL capacity was opperated, at constant temperature (32 ± 1º C), with substrate pH corrected between 5.5 and 6.0. The first stage had durations of 16.6; 13.6; 11.6; and 9.6 days and the organic loads were 3.1; 2.0; 2.3; and 2.9 COD L-1 d-1, (chemical oxigen demand) respectively. The second stage was characterized by a fixed HRT (4 days) and organic loads of 0.48; 0.86; 1.65; and 2.46 g COD L-1 d-1. Total solids (TS), volatile solids (VS), COD, alkalinity and volatile acidity were determined in the substrate and in the effluent. During the first stage, the HRT of 9.6 days and organic load of 2.9 g COD L-1 d-1 resulted in the best performence; reductions in COD, total and volatile solids were 60, 44 and 60%, respectively. During the second stage, with a 4-day HRT, the best results were achieved with the 0.86 g COD L-1 d-1 organic load, which provided reductions in COD, total and volatile solids of 71, 58 and 79%, respectively. The start-up of the plug-flow digester for manipueira treatment can be made by gradually by decreasing the HRT, or fixing HRT and increasing substrate concentration.
Stomatal responses of Eucalyptus species to elevated CO2 concentration and drought stress
Authors: Lima Walter de Paula , Jarvis Paul , Rhizopoulou Sophia
Published: April 2005

Five species of Eucalyptus (E. grandis, E. urophylla, E. camaldulensis, E. torelliana, and E. phaeotrica), among the ten species most commonly used in large scale plantations, were selected for studies on the effects of elevated CO2 concentration [CO2] and drought stress on stomatal responses of 2.5-month old seedlings. The first three species belong to the subgenus Smphyomyrtus, whereas the fourth species belongs to the subgenus Corymbia and E. phaeotrica is from the subgenus Monocalyptus. Seedlings were grown in four pairs of open-top chambers, arranged to have 2 plants of each species in each chamber, with four replications in each of two CO2 concentrations: 350 ± 30 mumol mol-1 and 700 ± 30 mumol mol-1. After 100 days in the chambers, a series of gas exchange measurements were made. Half the plants in each chamber, one plant per species per chamber, were drought-stressed by withholding irrigation, while the remaining plants continued to be watered daily. Drought stress decreased stomatal conductance, photosynthesis and transpiration rates in all the species. The effect of drought stress on stomatal closure was similar in both [CO2]. The positive effects of elevated [CO2] on photosynthesis and water use efficiency were maintained longer during the stress period than under well-watered conditions. The photosynthetic rate of E. phaeotrica was higher even in the fourth day of the drought stress. Drought stress increased photoinhibition of photosynthesis, as measured by chlorophyll fluorescence, which varied among the species, as well as in relation to [CO2]. The results are in agreement with observed differences in stomatal responses between some eucalyptus species of the subgenera Symphyomyrtus and Monocalyptus.
Alcobaça allele and genotypic backgrounds affect yield and fruit shelf life of tomato hybrids
Authors: Dias Túlio José Mendes , Maluf Wilson Roberto , Faria Marcos Ventura , Freitas Joelson André de , Gomes Luiz Antonio Augusto , Resende Juliano Tadeu Vilela , Azevedo Sebastião Márcio de
Published: April 2005

Post-harvest shelf life of tomato fruit may be increased by deploying mutant alleles which affect the natural ripening process and/or by a favorable genotypic background. Among the several ripening mutant genes, alcobaça (alc) has proved to be highly efficient in increasing shelf life of commercial tomato fruits, especially in heterozygosis, a state at which no limiting deleterious effects upon fruit color occur. The effects of heterozygosity in the alcobaça locus (alc+/alc) on yield and fruit quality traits of tomato hybrids with three genotypic backgrounds. We evaluated three pairs of hybrids obtained from crosses between the near-isogenic pollen source lines Flora-Dade (alc+/alc+) and TOM-559 (alc/alc), and three maternal lines (Stevens, NC-8276 and Piedmont). The six treatments were factorial combinations of two different status in the alc locus (alc+/alc and alc+/alc+) versus three different genotypic backgrounds (maternal lines). Fruits were harvested at the breaker stage of maturation and stored in shelves at 21ºC for 14 days. Yield and fruit quality traits were then evaluated. Regardless of the background, the alc allele in heterozygosis (alc+/alc) did not interfere with the total yield, commercial yield, average mass per fruit, average mass per commercial fruit, fruit shape, or with fruit peduncular scar diameter. The alc+/alc genotype reduced the rate of firmness loss and delayed evolution of the red color of the fruit, thus contributing to an increase of the post-harvest shelf life for all three genotypic backgrounds.
Potential of the ESA23B maize population for protein and oil content improvement
Authors: Mittelmann Andréa , Miranda Filho José Branco de , Lima Gustavo Júlio Mello Monteiro de , Hara-Klein Claudete , Tanaka Ricardo Takao
Published: April 2005

Among the traits that may add commercial value to maize (Zea mays L.), those related to nutritional quality, specially protein and oil content, are of great interest to the feed industry. The objective of this work was studying the variability of protein and oil content, as well as yield, in a group of maize testcrosses. One hundred and twenty S1 families of the ESA23B maize population were crossed with two testers, an open-pollinated population (BR108) and an exotic line (CML269). Testcrosses were evaluated at two locations under a completely randomized block design with three replications. Ear and grain yield, protein and oil content were evaluated. The three-way interaction location x tester x progeny was significant for all traits, except for oil content. Differences among progenies were detected for all traits. Testcross means varied from 8.40% to 11.82% for protein content and from 3.77% to 5.10% for oil content. Hybrids with similar or superior means to the best check were identified for protein content, ear yield, and grain yield. Estimates of the interpopulation additive variance ranged from 0.553 to 1.124 for protein content; 0.034 to 0.057 for oil content (percent data); 132.13 to 521.74 for ear yield and 116.33 to 381.73 for grain yield (data in grams per plant). The population ESA23B can potentially be improved for all the traits studied. Associations among traits were weak, thus concomitant selection of quality and yield can be feasible.
Mycorrhizal effectiveness and manganese toxicity in soybean as affected by soil type and endophyte
Authors: Nogueira Marco Antonio , Cardoso Elke Jurandy Bran Nogueira
Published: April 2005

Mycorrhizal plants may present Mn toxicity alleviation and this depends on the plant-endophyte-environment interaction. The effectiveness of three arbuscular mycorrhizal fungi (AMF) (Glomus macrocarpum, G. etunicatum, G. intraradices) and a control without AMF in two soils: Typic Rhodudalf with high Mn availability and a Typic Quartzipsamment, with low Mn availability, was evaluated in a time-course experiment at 3, 6, 9 and 12 weeks after soybean (Glycine max L.) seedling emergence. The objective was to select the most effective AMF species to enhance plant growth and to assess its effects upon Mn uptake by plants and Mn availability in the soil. For the sandy soil, AMF inoculation resulted in increased plant biomass, especially with G. intraradices and G. etunicatum. Lower Mn concentrations were observed in shoot and root of mycorrhizal plants. For the clayey soil, there was also an increase in plant biomass, but only for plants inoculated with G. intraradices and G. etunicatum. Mycorrhizal plants presented higher Mn concentrations in shoot and root and there was an increase of available Mn in the soil, in relation to the control, especially in the treatment with G. macrocarpum. When inoculated with G. macrocarpum, plants presented Mn toxicity symptoms and reduced biomass in comparison to control plants. The effects of mycorrhizal inoculation, either positive or negative, were most intense at 9 and 12 weeks.
Nutrient cycling in a RRIM 600 clone rubber plantation
Authors: Murbach Marcos Roberto , Boaretto Antonio Enedi , Muraoka Takashi , Souza Euclides Caxambu Alexandrino de
Published: April 2005

Few reports have been presented on nutrient cycling in rubber tree plantations (Hevea brasiliensis Muell. Arg.). This experiment was carried out to evaluate: the effect of K rates on the amount of nutrients transfered to the soil in a 13-year old Hevea brasilensis RRIM 600 clone plantation, nutrient retranslocation from the leaves before falling to the soil, and nutrient loss by dry rubber export. The experiment started in 1998 and potassium was applied at the rates of 0, 40, 80 and 160 kg ha-1 of K2O under the crowns of 40 rubber trees of each plot. Literfall collectors, five per plot, were randomly distributed within the plots under the trees. The accumulated literfall was collected monthly during one year. The coagulated rubber latex from each plot was weighed, and samples were analyzed for nutrient content. Increasing K fertilization rates also increased the K content in leaf literfall. Calcium and N were the most recycled leaf nutrients to the soil via litterfall. Potassium, followed by P were the nutrients with the highest retranslocation rates. Potassium was the most exported nutrient by the harvested rubber, and this amount was higher than that transfered to the soil by the leaf literfall.
Digital-image analysis to predict weight and yields of boneless subprimal beef cuts
Authors: Teira Gustavo Adolfo , Tinois Eduardo , Lotufo Roberto de Alencar , Felício Pedro Eduardo de
Published: April 2005

For several decades, beef carcass evaluation for grading or research purposes has relied upon subjective visual scores, and manually taken measurements, but in recent times there has been a growing interest in new technologies capable of improving accuracy of estimates. Equations to predict weight and yield of beef pistol subprimal cuts were developed in this work using digital image analysis (VIA) of the 12th rib steak. Equations to predict total pistol subprimal cuts weight (CUTS) had coefficients of determination (CD) of 0.84, or 0.87 to 0.88, when the independent variables were the VIA parameters and the half carcass weight (HC) or the total pistol weight (TP), respectively. The predicted values for the total seven subprimal cuts, as a percentage of half carcass weight (CUTS%), presented CD values ranging from 0.37 to 0.47, or 0.21 to 0.31, using HC or TP as a principal independent variable. Likewise, the equation for weight of the individual subprimal cuts had CD values ranging from 0.40 to 0.72, or 0.43 to 0.74 using HC or TP, respectively. In this research, the developed VIA procedure has demonstrated good repeatability and accuracy to estimate the total pistol subprimal weights, and some individual subprimal weights.
Cupric citrate as growth promoter for broiler chickens in different rearing stages
Authors: Brainer Mônica Maria de Almeida , Menten José Fernando Machado , Vale Marcos Martinez do , Morais Sônia Cristina Daroz de
Published: April 2005

Feeding cupric citrate as alternative to cupric sulfate to broilers has been suggested in the literature. Day-old male broiler chicks (1,200) were used in an experiment to evaluate the efficacy of cupric citrate supplementation (75 mg Cu kg-1) during the 1-21, 22-42 or 1-42 d periods in comparison to an unsupplemented diet and a diet supplemented with cupric sulfate (200 mg Cu kg-1, 1-42 d). A randomized block design was used, with five treatments, six replicates and 40 birds per pen. The diets, based on corn and soybean meal, and water were offered ad libitum during the 42-day experimental period. Over the entire period, there was no effect of copper supplementation (P > 0.05) on bird live weight, weight gain, feed intake, feed conversion and mortality. Cupric citrate supplementation on the 22-42 d period resulted in worse feed conversion as compared to broilers receiving cupric sulfate (2.014 vs. 1.967, P < 0.05). Copper residues in the litter were reduced when broilers were fed cupric citrate, as compared to cupric sulfate (P < 0.01). The absence of response to copper supplementation can be attributed to the environmental and sanitary rearing conditions.
Logistic rice model for dry matter and nutrient uptake
Authors: García y García Axel , Dourado-Neto Durval , Basanta Maria del Valle , López Ovejero Ramiro Fernando , Favarin José Laércio
Published: April 2005

The temporal variation of cumulative dry matter can be represented by a sigmoidal curve and the temporal variation of nutrient uptake follows this characteristic shape. Therefore, modeling the temporal variation of cumulative dry matter allows estimating nutrient uptake along the crop cycle. The objective of this study was to propose a sine model to estimate dry matter and macronutrient uptake, and to estimate the moments of maximum N and K uptake rates for the rice crop. The field experiment was carried out on a wetland area of Piracicaba, SP, Brazil, consisting of an Humic Haplaquept. The chosen rice variety was IAC 103, a middle season cycle and high yield. Observed variables were dry matter of different plant parts (root, leaf and stem, and panicle) and macronutrient contents per unit dry matter. A sine model was proposed for the cumulative variation of these variables, based on biological events that occurred during the crop cycle. The temporal variation of nutrient uptake was estimated and a lower accuracy was observed for K uptake. The maximum absorption rate for N and K was found at 56% of the relative development of the crop, corresponding to 60 days after emergence in this experiment. The proposed model presented a satisfactory behavior to define the order of magnitude of estimated dry matter and macronutrient uptake by the rice crop and maximum N and K uptake rates.