bluuebunny/crossref_metadata_2025 huggingface dataset:
Variabilidade e correlações entre caracteres em cruzamentos de soja
Authors: Lopes Ângela Celis de Almeida , Vello Natal Antonio , Pandini Fábio , Rocha Maurisrael de Moura , Tsutsumi Claudio Yuji
Published: April 2005

A estimação de parâmetros em gerações iniciais de endogamia tem importância para direcionar o programa de melhoramento, principalmente em relação ao processo de seleção dos genótipos mais promissores. Este trabalho avaliou 21 genótipos de soja (seis parentais e 15 combinações dialélicas em F2), em dois locais (ESALQ e Anhembi) de Piracicaba, SP. O delineamento usado foi em blocos ao acaso, com seis repetições por local. A parcela experimental foi de 12 covas de plantas individuais espaçadas de 0,80 m x 0,80 m. Os caracteres avaliados foram número de dias e altura da planta no florescimento e maturidade; valor agronômico; produtividade de grãos; teor de óleo na semente e produtividade de óleo. Todas as estimativas de parâmetros basearam-se nos componentes das análises de variância e covariância individuais e conjuntas. Parentais e F2 apresentaram variabilidade para todos os caracteres. Em termos de qualidade ambiental favorável, os dois locais foram bons para a expressão do potencial genético dos genótipos, no entanto, o local Anhembi foi mais favorável para produtividade de grãos. A interação genótipos x locais mostrou-se um importante componente da variação fenotípica, com exceção do caráter teor de óleo. As correlações genotípicas foram geralmente maiores que as fenotípicas e de ambiente nos dois locais. A magnitude das correlações fenotípicas e genotípicas mostrou que o fenótipo refletiu satisfatoriamente o genótipo. Os caracteres relacionados ao florescimento e à maturidade mostraram-se importantes para o melhoramento da produtividade, com destaque para o valor agronômico. Existe evidência de dificuldades em obter novos genótipos produtivos e precoces.
Cations extraction of sandy-clay soils from cavado valley, portugal, using sodium salts solutions
Authors: Silva João Eudes da , Castro Fernando
Published: April 2005

Cases of contamination by metals in the water wells of the Cavado Valley in north-west Portugal can be attributed to the heavy leaching of clay soils due to an excess of nitrogen resulting from the intensive use of fertilisers in agricultural areas. This work focuses on the natural weathering characteristics of soils, particularly the clay material, through the study of samples collected near the River Cavado. Samples taken from various sites, after physico-chemical characterisation, were subjected to clay dissolution tests, using sodium salts of different ionic forces, to detect the relationship between certain physico-chemical parameters of water, such as pH, nitrate, chloride and sulphate content, in the dissolution of clay and the subsequent extraction of such cations as Al, Fe and K. In acidic sandy clay soils, the mineralogical composition of which was characterised by a predominance of quartz, micas, kaolinite and K-feldspars, decreases of the clay material/water pH ratio increases dissolution of the micaceous and K-feldspars phases. The presence of nitrates in the aqueous solution apparently advanced the extraction of all three cations Al, Fe and K. The specific surface area of the clay material showed a significant correlation with the main kinetic parameters of cation extraction.
Alteração de plagioclásios dos riodacitos da formação serra geral (JKsg) da região de Piraju - SP
Authors: Truffi Silvia Alessandra , Clemente Celso Augusto
Published: April 2005

A região de Piraju -- SP é caracterizada geologicamente por apresentar uma grande distribuição de rochas básicas e ácidas da Formação Serra Geral. Os processos e produtos de alteração das rochas básicas são apresentados em muitos trabalhos, mas estudos envolvendo alteração de rochas vulcânicas ácidas são raros. Apresentam-se os resultados de estudos petrológicos, químicos e mineralógicos nas rochas vulcânicas ácidas (riodacitos da Formação Serra Geral), nos produtos de alteração dessas rochas, dando ênfase para a evolução mineralógica dos plagioclásios. Os riodacitos da Fm. Serra Geral (JKsg) possuem em sua composição mineralógica cerca de 60-65% de plagioclásios configurando assim a parte mais importante de sua constituição. O estudo da alteração desses plagioclásios oferece informações importantes em relação a própria alteração da rocha e dos solos relacionados. Resultados obtidos a partir de análises de microscopia óptica, difratometria de raios-X aliados a determinações químicas qualitativas e semi-quantitativas obtidas por microscopia eletrônica de varredura (MEV) permitiram importantes interpretações e conclusões sobre a evolução da alteração nos plagioclásios, a saber: a) por meio de intemperismo não muito intenso, isto é, processo de hidrólise parcial (monossialitização) os cristais de plagioclásio evoluem principalmente para caulinita e secundariamente para mica e haloisita; b) por meio de intemperismo intenso, isto é, processo de hidrólise total (alitização) os cristais de plagioclásio evoluem para gibbsita.
Manipulation of fire ant density, Solenopsis spp., for short-term reduction of Diatraea saccharalis larval densities in Brazil
Authors: Rossi Marcelo Nogueira , Fowler Harold Gordon
Published: April 2005

The sugarcane borer, Diatraea saccharalis (Fabr.) is the main sugarcane pest in Brazil. In the State of São Paulo, the main active population control of D. saccharalis is by inundative releases of the exotic parasitoid, Cotesia flavipes (Cam.). However, the production of C. flavipes in sugar mills entails costs and few studies have evaluated the effects of native predators on sugarcane borer populations. Using a simple colony translocation method, we evaluated the effect of fire ants (Solenopsis spp.) on population densities of D. saccharalis and concurrently upon rates of parasitism by classical biological control agents in the São João sugar mill in the State of São Paulo, Brazil. The translocation technique proved to be feasible and economically possible. Sugarcane borers were sampled in each of the 5 areas for each treatment in two 1.4 x 5.0 m (7 m²) points (sample size), by opening and visually examining all canes. The average numbers and its respective standard deviations (SD) for D. saccharalis population densities before and after colony translocations considering 0, 5, 10 and 15 colonies added per 0.5 ha were, 9.2 ± 5.9, 8.4 ± 3.4, 9.0 ± 6.9, 9.4 ± 8.1 and 3.2 ± 1.8, 2.8 ± 2.7, 2.6 ± 1.5, 3.8 ± 2.8, respectively. However, we detected no significant changes in sugarcane borer densities with respect to ant colony densities over a two-week period, none of which were greater than for no colony additions. No effects of colony translocations on parasitism rates of braconid and tachinid parasitoids on D. saccharalis were detected. Thus, although the translocation technique was economically feasible, no reductions of D. saccharalis densities were produced by colony additions, and may not be a viable alternative for D. saccharalis population reduction, especially at the low population levels which prevail in Brazil.
Field comparison between selection methods at the maize seedling stage in relation to aluminum tolerance
Authors: Giaveno Carlos Daniel , Miranda Filho José Branco de
Published: April 2005

Selection and breeding for aluminum tolerance is a useful approach to increase maize (Zea mays L.) grain yield in acid soils. The objective of this work was the comparison between two screening approaches for the development of Al tolerant maize populations. One cycle of divergent selection for aluminum tolerance, using both nutrient solution and pots with acid soil, were completed in the maize population SIKALQ. The four sub-populations selected through both selection procedures were compared with the original population and checks in field trials repeated over locations. Eight environments stratified into four groups varying from non acid to high aluminum saturation were used. Three variables were analyzed for comparisons of methodologies: grain yield, plant height and days to male flowering. The populations performed similarly in the high productivity locations and the differences between tolerant and sensitive ones were more evident for increasing levels of toxic aluminum. In spite of little differences, selection in pots with acid soil was more efficient than nutrient solution in changing the genetic structure of the population toward more tolerant and sensitive levels.
Fruit characterization of high oil content avocado varieties
Authors: Gómez-López Vicente Manuel
Published: April 2005

To expand the data bank on avocado (Persea americana Mill.) varieties all over the world, and to select good varieties for commercial or improving purposes, a partial fruit characterization of 13 high oil content (11.23-18.80%) was performed. The chosen varieties are growing in a Venezuelan germplasm bank: Fuerte, Peruano, Lula, Ortega, Red Collinson, Alcemio, Araira 1, Pope, Ettinger, Gripiña 5, Barker, Duke, and Ryan. They were characterized for pulp oil and moisture; weight (whole fruit, seed, pulp and peel); length, width and fruit shape; peel characteristics (roughness, color and hand peeling); and ripeness time. The variety Ryan showed the highest oil content (18.80%) and calorific value (191 Kcal/100 g wet flesh). Avocado varieties grown in Venezuela have generally less oil content and are generally lighter than those from other countries. Most of the varieties had low pulp proportion, and were pyriform, with rough green peel and difficult to hand peel. Red Collinson had an uncommon reddish peel. The ripening time was between 4 and 10 days after harvest.
Meta-análise para estimativas de correlação genética entre pesos ao nascer e desmama de bovinos
Authors: Giannotti Juliana Di Giorgio , Packer Irineu Umberto , Mercadante Maria Eugênia Zerlotti
Published: April 2005

O problema de combinar informações de estudos independentes atinge quase todos os campos da ciência, devido, principalmente, ao grande número de artigos científicos publicados nos últimos anos, assim sumarizar informações se tornou uma necessidade. Uma meta-análise foi conduzida com o objetivo de resumir as estimativas da correlação genética entre pesos ao nascer e desmama de bovinos de corte de origem zebuína. Foi usado um conjunto de estimativas obtidas em 39 artigos publicados no período de 1968 a 2000. Os dados foram analisados de acordo com modelos fixo e aleatório, este último sob a técnica da máxima verossimilhança restrita. O modelo fixo não foi apropriado em virtude da falta de homogeneidade das estimativas de correlação, sendo portanto recomendável o modelo aleatório. A análise de subgrupo, estratificado por década de publicação, também apresentou heterogeneidade. A meta-análise constitui técnica que deve ser implementada para esta e outras finalidades
Simulation of mixed models in augmented block design
Authors: Santos Aladir Horacio , Bearzoti Eduardo , Ferreira Daniel Furtado , Silva Filho João Luís da
Published: April 2005

The augmented block design is widely used in breeding programs, with non-replicated treatments generally being selection units, and replicated treatments being standard cultivars. Originally, an intrablock analysis (fixed model) was proposed. Although non-replicated treatments and/or blocks can be considered of random nature, mixed linear models could be used instead. This work evaluated such an approach, using computer simulation. Populations consisted of sets of randomly generated inbred lines. Molecular marker data were also simulated to allow the estimation of the genetic covariance matrix. Different conditions were considered, varying heritability and the coefficient b of Smith of soil heterogeneity. For each condition 100 simulations were performed, considering four linear models, varying respectively the nature of the effects of blocks and non-replicated treatments (fixed - F, or random - R): FF, FR, RF and RR. In relation to FF, the mixed models were more efficient under low to intermediate heritability and high b. Mixed models could improve inference in breeding programs using the augmented block design and the choice of the model should rely on the kind of selection. If this is truncated, the RF model should be preferred; if it is not, then the RR model would be more suitable.
Curvas de dose-resposta de biótipos resistente e suscetível de Bidens pilosa L. aos herbicidas inibidores da ALS
Authors: Christoffoleti Pedro Jacob
Published: April 2005

A resistência de plantas daninhas aos herbicidas é um fenômeno de ocorrência mundial, sendo caracterizada como uma redução na resposta de uma população a produtos químicos, em sua dose recomendada, como resultado de sua aplicação sucessiva. O número de casos de resistência registrados no Brasil tem aumentado significativamente nos últimos anos, porém poucos estudos científicos têm sido feitos para elucidar este fenômeno. Sendo assim, foram conduzidos experimentos com o objetivo de elaboração de curvas de dose-resposta comparativa entre dois biótipos da planta daninha picão-preto (Bidens pilosa L.), sendo um resistente (R) e outro suscetível (S) aos herbicidas inibidores da ALS. Para isso, foram utilizados três herbicidas do grupo químico das sulfoniluréias e um do grupo químico das imidazolinonas. No estádio de três a quatro pares de folhas, as plantas R e S de B. pilosa foram pulverizadas com os herbicidas chlorimuron-ethyl, metsulfuron-methyl, nicosulfuron e imazethapyr, em doses correspondentes a múltiplos de 0,0; 0,001; 0,01; 0,1; 1,0; 10; 100 e 1000 vezes a dose recomendada para aplicação de campo. A partir dos resultados da porcentagem de fitotoxicidade foi feito o ajuste das curvas de dose-resposta. As relações entre o C50 do biótipo resistente e o C50 do biótipo suscetível (R/S) foram de 40,92; 173,84; 57,47 e 57,16 para os herbicidas chlorimuron-ethyl, nicosulfuron, metsulfuron-methyl, e imazethapyr, respectivamente. O biótipo R de B. pilosa apresenta elevado nível de resistência cruzada aos herbicidas inibidores da ALS, do grupo químico das sulfoniluréias e imidazolinonas.
Eficiência de absorção e utilização de fósforo (32P) por mudas de eucalipto e arroz
Authors: Luca Edgar Fernando de , Boaretto Antonio Enedi , Muraoka Takashi , Chitolina José Carlos
Published: April 2005

O conhecimento das habilidades das plantas em absorver o fósforo do solo e utilizá-lo no seu crescimento é uma via que pode ser importante para melhorar sensivelmente a eficiência da adubação fosfatada. Conduziu-se um experimento em casa-de-vegetação com objetivo de testar a hipótese de que o eucalipto é mais eficiente do que o arroz em absorver o fósforo de fontes poucos solúveis aplicadas a um Neossolo Quartzarênico, em função dos conceitos de eficiência. As fontes de fósforo Ca(H2(32)PO4).H 2O, CaH32PO4.2H2O e Ca3(32PO4)2 , sintetizadas em laboratório e identificadas por análises de difratometria de raios-X e térmica diferencial, foram utilizadas como traçadores isotópicos. O arroz foi mais eficiente em absorver o fósforo de fontes pouco solúveis, enquanto que o eucalipto apresentou maior utilização biológica do fósforo. O método da diferença (convencional) empregado para determinar a recuperação de P pelas plantas subestimou a absorção deste nutriente, por ambas as culturas, em relação ao método isotópico.
Poder de detecção de "Quantitative Trait Loci", da análise de marcas simples e da regressão linear múltipla
Authors: Silva Heyder Diniz , Vencovsky Roland
Published: April 2005

O mapeamento de locos envolvidos no controle gênico de caracteres quantitativos, QTL's, difere dos demais tipos de experimentos conduzidos em genética, por tratar-se, basicamente, de um procedimento de testes múltiplos. Um problema decorrente deste tipo de análise refere-se ao nível de significância conjunto e, consequentemente ao poder da mesma. Em vistas disto avaliou-se, via simulação computacional de dados, o poder de detecção de QTL's da análise de marcas simples, utilizando os critérios da razão de falsas descobertas (FDR) e de Bonferroni para determinação nível de significância conjunto alfa* e da regressão linear múltipla, empregando o procedimento "stepwise" para seleção das marcas. O procedimento baseado em regressão múltipla foi mais poderoso em identificar as marcas associadas a QTL's, do que os procedimentos baseados em testes individuais, utilizando tanto o critério FDR, quanto o de Bonferroni para o controle do nível de significância conjunto. Mesmo nos casos em que esse procedimento apresentou poder ligeiramente inferior aos demais, mostrou a grande vantagem de selecionar apenas as marcas mais fortemente ligadas a QTL's, devendo, portanto, ser preferido para seleção das marcas a serem utilizadas como covariáveis no processo de mapeamento por intervalo múltiplo. Dentre os critérios FDR e de Bonferroni, que são aplicáveis aos métodos de mapeamento por intervalo, o primeiro mostrou-se mais poderoso, devendo portanto ser preferido.
Selection methods for maize seedlings in greenhouse as related to aluminum tolerance
Authors: Giaveno Carlos Daniel , Miranda Filho José Branco de
Published: April 2005

Genetic improvement is a useful approach to increase aluminum tolerance in maize. This experiment was carried out to compare two screening techniques under greenhouse conditions and estimate the association between the results obtained for both bioassays with grain yield. Nutrient solution (NS) and pots with acid soil (AS) were utilized as screening methodologies to perform one cycle of divergent selection for aluminum tolerance in the tropical maize population SIKALQ. The four sub-populations obtained by both approaches were compared with the original and checks in a greenhouse and in multilocation field trials. Evaluation under the conditions of NS and AS showed that the populations with the best performances were those selected for aluminum tolerance under the same condition of evaluation. The variables measured in greenhouse showed good correlation and the most closely related were fresh root weight (FRW) and dry rot weight (DRW) (0.79). All of these variables showed low correlation with yield in non acid conditions (< 0.30). The correlation was more important (~ 0.50) as soil aluminum saturation increased. The best correlation was observed for visual scoring (VS) (0.68), FRW (0.47) and net root growth (NRG) (0.52).
Isoenzymatic variability in tropical maize populations under reciprocal recurrent selection
Authors: Pinto Luciana Rossini , Vieira Maria Lúcia Carneiro , Souza Jr. Cláudio Lopes de , Silva Rainério Meireles da
Published: April 2005

Maize (Zea mays L.) is one of the crops in which the genetic variability has been extensively studied at isoenzymatic loci. The genetic variability of the maize populations BR-105 and BR-106, and the synthetics IG-3 and IG-4, obtained after one cycle of a high-intensity reciprocal recurrent selection (RRS), was investigated at seven isoenzymatic loci. A total of twenty alleles were identified, and most of the private alleles were found in the BR-106 population. One cycle of reciprocal recurrent selection (RRS) caused reductions of 12% in the number of alleles in both populations. Changes in allele frequencies were also observed between populations and synthetics, mainly for the Est 2 locus. Populations presented similar values for the number of alleles per locus, percentage of polymorphic loci, and observed and expected heterozygosities. A decrease of the genetic variation values was observed for the synthetics as a consequence of genetic drift effects and reduction of the effective population sizes. The distribution of the genetic diversity within and between populations revealed that most of the diversity was maintained within them, i.e. BR-105 x BR-106 (G ST = 3.5%) and IG-3 x IG-4 (G ST = 4.0%). The genetic distances between populations and synthetics increased approximately 21%. An increase in the genetic divergence between the populations occurred without limiting new selection procedures.
Soil management and nitrogen fertilization for sprinkler-irrigated upland rice cultivars
Authors: Arf Orivaldo , Rodrigues Ricardo Antonio Ferreira , Crusciol Carlos Alexandre Costa , Sá Marco Eustáquio de , Buzetti Salatiér
Published: April 2005

The use of sprinkler irrigation for rice (Oryza sativa L.) crop is a relatively recent practice in Brazil. Therefore, crop soil and fertilization management are still not very well defined. Another problem is the inexistence of specific cultivars adapted to this cropping system. This study aimed to evaluate sprinkler-irrigated upland rice cultivars under different soil management practices and nitrogen sidedressing rates in relation to yield and grain quality. A randomized block design was used, arranged as a 3 x 3 x 5 factorial scheme, totaling 45 treatments consisting of the combination of three rice cultivars (Primavera, Confiança and Maravilha), three soil management systems (disk harrow + levelling harrow, moldboard plow + levelling harrow and no-till) and five nitrogen rates, applied as sidedressing (0, 25, 50, 75 and 100 kg ha-1), with four replicates. The experiment was set up during the 1999/2000 and 2000/2001 cropping seasons, in Selvíria, MS, Brazil, on a Typic Haplustox of clayey texture. Cultivars Primavera and Maravilha presented higher grain yield than Confiança; on the other hand the latter showed higher milled and head rice yields during seed processing. Soil tillage with the moldboard plow and no-till interfered positively in the agronomic and productive characteristics of the crop. In relation to milled rice yield, tilling with the levelling disk + moldboard plow showed better results in relation to no-till. Nitrogen sidedressing did not interfere with the agronomic and productive characteristcs as well as with the milled rice yield of all cultivars.
Grapevine root distribution in drip and microsprinkler irrigation
Authors: Bassoi Luis Henrique , Hopmans Jan W. , Jorge Lúcio André de Castro , Alencar Cristina Miranda de , Silva José Antonio Moura e
Published: April 2005

Grape (Vitis vinifera L.) yield and its quality are dependent of the status of the root system. Root distribution information is also valuable for soil and water management. An analysis of methods to evaluate the root distribution of grapevines for both, drip and microsprinkler irrigation in a Typic Acrustox is presented for the table grape cv. Italia grafted on the rootstock IAC-313, in northeastern Brazil. Measured root parameters using the monolith method were root dry weight (Dw) and root length density (Lv), while root area (Ap) was estimated using the soil profile method in combination with digital image analysis. For both irrigation systems, roots were present to the 1 m soil depth and extended laterally to 1 m distance from the trunk, but grapevines irrigated by microsprinkler showed greater root presence as the distance from the trunk increased. Values of Ap were reasonably well correlated to Dw and Lv. However, correlation values were higher when fractional root distribution was used. The soil profile method in combination with image analysis techniques, allows proper grapevine root distribution evaluation.
Practical method for germination of Araucaria angustifolia (Bert.) O. Ktze. seeds
Authors: Moreira-Souza Milene , Cardoso Elke Jurandy Bran Nogueira
Published: April 2005

The germination of seeds of Araucaria angustifolia (Brazilian Pine) is generally a slow and fastidious process that causes loss of many seeds because of the incidence of pathogens. The objective of this study was to evaluate whether seeds with cut edges present greater germination percentages or precocity when compared to untreated, normal seeds. The experimental design was completely randomized design with 100 pre-cut and 100 non-treated seeds. The experiment was installed twice, in 1998 and 1999, from fresh seeds. Pre-cut seed germination was higher: 92 and 95% respectively, whereas whole seed germination was 60 and 64% in the two experiments. Seedlings originated from pre-cut seeds were uniform and showed less fungal contaminants.
Multiperspective analysis of erosion tolerance
Authors: Sparovek Gerd , De Maria Isabella Clerici
Published: April 2005

Erosion tolerance is the most multidisciplinary field of soil erosion research. Scientists have shown lack in ability to adequately analyze the huge list of variables that influence soil loss tolerance definitions. For these the perspectives of erosion made by farmers, environmentalists, society and politicians have to be considered simultaneously. Partial and biased definitions of erosion tolerance may explain not only the polemic nature of the currently suggested values but also, in part, the nonadoption of the desired levels of erosion control. To move towards a solution, considerable changes would have to occur on how this topic is investigated, especially among scientists, who would have to change methods and strategies and extend the perspective of research out of the boundaries of the physical processes and the frontiers of the academy. A more effective integration and communication with the society and farmers, to learn about their perspective of erosion and a multidisciplinary approach, integrating soil, social, economic and environmental sciences are essential for improved erosion tolerance definitions. In the opinion of the authors, soil erosion research is not moving in this direction and a better understanding of erosion tolerance is not to be expected in the near future.
Soybean yield estimation by an agrometeorological model in a GIS
Authors: Berka Luciana Miura Sugawara , Rudorff Bernardo Friedrich Theodor , Shimabukuro Yosio Edemir
Published: April 2005

Agrometeorological models interfaced with the Geographic Information System - GIS are an alternative to simulate and quantify the effect of weather spatial and temporal variability on crop yield. The objective of this work was to adapt and interface an agrometeorological model with a GIS to estimate soybean [Glycine max (L.) Merr.] yield. Yield estimates were generated for 144 municipalities in the State of Paraná, Brazil, responsible for 90% of the soybean production in the State, from 1996/1997 to 2000/2001. The model uses agronomical parameters and meteorological data to calculate maximum yield which will be penalized under drought stress. Comparative analyses between the yield estimated by the model and that reported by the Paraná State Department of Agriculture (SEAB) were performed using the "t" test for paired observations. For the 1996/1997 year the model overestimated yield by 10.8%, which may be attributed to the occurrence of fungal diseases not considered by the model. For 1997/1998, 1998/1999 and 1999/2000 no differences (P > 0.05) were found between the yield estimated by the model and SEAB's data. For 2000/2001 the model underestimated yield by 10.5% and the cause for this difference needs further investigation. The model interfaced with a GIS is an useful tool to monitor soybean crop during growing season to estimate crop yield.
Nutrient losses by water erosion
Authors: Bertol Ildegardis , Mello Eloy Lemos , Guadagnin Jean Cláudio , Zaparolli Almir Luis Vedana , Carrafa Marcos Roberto
Published: April 2005

Water erosion causes soil degradation, which is closely related to nutrient losses either in, the soluble form or adsorbed to soil particles, depending mainly on the adopted soil management system. This study was carried out in São José do Cerrito, SC, Brazil, between March 2000 and June 2001. The objective was to quantify available nitrogen, phosphorus, potassium, calcium and magnesium losses in water erosion obtained with simulated rainfall in the following soil management systems: conventional tillage with no-crop (bare soil) (BS), conventional tillage with soybean (CT), reduced tillage with soybean (RT), no tillage with soybean on a desiccated and burned natural pasture (DBNP), and no tillage with soybean on a desiccated natural pasture (DNP). A rotating boom rainfall simulator was used to perform three rainfall tests with constant intensity of 64 mm h-1 and sufficient duration to reach constant runoff rate, on a clayey-loam, well-structured Typic Hapludox, with an average slope of 0.18 m m-1. The first test was carried out five days before soybean emergence and the second and third at 30 and 60 days, respectively. The nutrient concentration in water and total losses of nitrogen, phosphorus, potassium, calcium and magnesium were higher under CT than in the other soil management systems.
Phytase enzyme in diets containing defatted rice bran for growing swine
Authors: Moreira José Aparecido , Vitti Dorinha Miriam Silber Schmidt , Trindade Neto Messias Alves da , Lopes João Batista
Published: April 2005

Organic phosphorus is poorly utilized by monogastric animals because they lack phytase, the enzyme that cleaves the ortho-phosphate groups from the phytate molecule. Diets fed to pigs are supplemented with inorganic P, and this can increase environmental pollution and diet costs. Sixty mixed sex, half-breed pigs, were used to evaluate the effect of increasing dietary levels of phytase (253, 759, 1265 and 1748 PU kg-1 feed) on animal performance as compared to a control without phytase but supplemented with dicalcium phosphate. Enzyme levels did not affect daily feed intake, food conversion, average daily weight gain, plasma P and Ca, calcium and phosphorus in bone ash, and the calcium/phosphorus ratio in the plasma and bones. A quadratic relationship between phytase levels and the percentages of P and Ca in bone ash was observed, reaching a maximum at the 880 and 879 PU levels, respectively. Animals fed diets containing phytase presented low plasma P values when compared to the control, but no effects were observed for the regression analysis. Using 759 PU phytase in rations containing corn, soybean bran and defatted rice bran for growing pigs can eliminate the use of traditional sources of P.
Biological aspects and life table of Uroleucon ambrosiae (Thomas, 1878) as a function of temperature
Authors: Auad Alexander Machado , Moraes Jair Campos de
Published: April 2005

The aphid Uroleucon ambrosiae (Thomas) is considered a pest of hidroponically-grown lettuce, but basic and applied information on its control are scarce in Brazil. The aim of this study was to determine the effect of different temperatures on biological aspects and life history of U. ambrosiae (Thomas) developing on hydroponic lettuce (Lactuca sativa L.) crop. Newly emerged nymphs were placed on 4-cm discs of hydroponic lettuce, var. Verônica, which were maintained on 5-cm Petri dishes, at temperatures of 15, 20 and 25ºC and 14 h photophase, and inside a greenhouse, within micro-cages at room temperature. The duration of development in all nymphal stages varied inversely to temperature. Nymphs maintained at 20ºC and 25ºC, had similar development period. However, at fluctuating greenhouse temperatures (daily mean = 21ºC), different results were obtained, which was also true for the pre-reproductive, reproductive and post-reproductive periods. Daily and total fertilities at 20ºC were better in comparison to the other treatments. The highest mortality rate of aphids occurred under greenhouse conditions. The production of 1.28 nymphs per female per day, the time needed for the population to double in size (TD=2.77days), and the intrinsic rate of population increase (r m=0.25), were similar for in insects maintained at 20 and 25ºC. On the other hand, time interval between generations (T) and the net reproductive rate (Ro) were higher at 20ºC. In the greenhouse, even though T was similar to laboratory conditions at 20 and 25ºC, the R0, r m and l parameters were lower and TD was higher. Based on biological aspects, fertility and life expectancy tables, constant temperature of 20ºC is the most suitable for U. ambrosiae.
Fermentation of irradiated sugarcane must
Authors: Alcarde André Ricardo , Walder Júlio Marcos Melges , Horii Jorge
Published: April 2005

Bacillus and Lactobacillus are bacteria that usually contaminate the ethanolic fermentation by yeasts and may influence yeast viability. As microorganisms can be killed by ionizing radiation, the efficacy of gamma radiation in reducing the population of certain contaminating bacteria from sugarcane must was examined and, as a consequence, the beneficial effect of lethal doses of radiation on some parameters of yeast-based ethanolic fermentation was verified. Must from sugarcane juice was inoculated with bacteria of the genera Bacillus and Lactobacillus. The contaminated must was irradiated with 2.0, 4.0, 6.0, 8.0 and 10.0 kGy of gamma radiation. After ethanolic fermentation by the yeast (Saccharomyces cerevisiae) the total and volatile acidity produced during the process were evaluated; yeast viability and ethanol yield were also recorded. Treatments of gamma radiation reduced the population of the contaminating bacteria in the sugarcane must. The acidity produced during the fermentation decreased as the dose rate of radiation increased. Conversely, the yeast viability increased as the dose rate of radiation increased. Gamma irradiation was an efficient treatment to decontaminate the must and improved its parameters related to ethanolic fermentation, including ethanol yield, which increased 1.9%.
Plant regeneration from proroplasts of alfalfa (Medicago sativa) via somatic embryogenesis
Authors: Monteiro Mariza , Appezzato-da-Glória Beatriz , Valarini Maria José , Oliveira Carlos Alberto de , Vieira Maria Lucia Carneiro
Published: April 2005

Alfalfa is one of the most frequently studied species from the production of tissue culture-derived embryos point of view. In this study, five alfalfa cultivars were analyzed with reference to their ability to regenerate plants from protoplast cultures via somatic embryogenesis. Plant regeneration from leaf-derived protoplasts isolated from the cultivar Rangelander was achieved using a protocol defined for alfalfa cell suspension-derived embryogenesis. Because of its high efficiency, this procedure is recommended for protoplast electroporation-mediated genetic transformation of alfalfa.
Selected mild strains of Passion fruit woodiness virus (PWV) fail to protect pre-immunized vines in Brazil
Authors: Novaes Quelmo Silva de , Rezende Jorge Alberto Marques
Published: April 2005

The Passion fruit woodiness virus (PWV) is the most important virus affecting passion fruit (Passiflora edulis f. flavicarpa Deg.) crops in Brazil. The main purpose of this work was to select mild strains of PWV and to evaluate their protective effect against a severe strain of the virus. Three mild strains were selected from outstanding plants found in orchards severely affected by the virus (F-101, F-102 and F-103) and three others were obtained from blisters formed in passion fruit vine leaves showing mosaic (F-99, F-144 and F-145). The protective effect of the mild strains was evaluated for vines under greenhouse and field conditions. Plants pre-immunized with mild strains F-101, F-102 and F-144, in a greenhouse, had partial protection against the severe strain PWV-SP. In a first field experiment, all passion fruit vines pre-immunized with the six selected mild strains showed severe symptoms of the disease, approximately four months after the challenge inoculation with the PWV-SP strain. Results from a second field experiment, with vines pre-immunized with strains F-101 and F-144, followed by a quantitative evaluation of the mild strains in different leaves of the protected plants, indicated that breakdown in protection seems to be related to the low concentration and/or irregular distribution of the mild strains in leaves, which allows the existence of infection sites available for the establishment of the severe strain. Pre-immunization was not an appropriate alternative for the control of the passion fruit woodiness disease.
Ultrasonography as a predicting tool for carcass traits of young bulls
Authors: Suguisawa Liliane , Mattos Wilson Roberto Soares , Oliveira Henrique Nunes de , Silveira Antônio Carlos , Arrigoni Mário de Beni , Haddad Cláudio Maluf , Chardulo Luis Artur Loyola , Martins Cyntia Ludovico
Published: April 2005

Considerable resources have been allocated to support research in the development of non-invasive and non-destructive techniques for carcass composition and quality evaluation. Ultrasonography is a reliable and relatively low-cost technique that can be used. In the present study, real-time ultrasonography was used to predict ribeye area (REA) and subcutaneous fat thickness (FT) in live animals as compared to carcass measurements. Animals used were 115 yearling bull calves (initial body weight, 329 kg), kept under feedlot conditions, of four genetic groups (30, ½ Angus x Nellore; 30, ½ Canchim x Nellore; 30, ½ Simmental x Nellore, and 25 Nellore), and two finishing frame sizes (small and large). Four ultrasonographic measurements were taken every 28 days until slaughter. Predictive precision of ultrasonographic measurements increased as animals approached slaughter, reaching maximum values at the last measurement (R²=0.68 and 0.82 for REA and FT, respectively). FT carcass measurements was influenced by genetic group and live measurements (P < 0.05). Frame size did not influence REA and FT, probably due to small, but distinctive differences among genetic groups.
Biosolids and heavy metals in soils
Authors: Silveira Maria Lucia Azevedo , Alleoni Luís Reynaldo Ferracciú , Guilherme Luiz Roberto Guimarães
Published: April 2005

The application of sewage sludge or biosolids on soils has been widespread in agricultural areas. However, depending on their characteristics, they may cause increase in heavy metal concentration of treated soils. In general, domestic biosolids have lower heavy metal contents than industrial ones. Origin and treatment method of biosolids may markedly influence their characteristics. The legislation that controls the levels of heavy metal contents in biosolids and the maximum concentrations in soils is still controversial. In the long-term, heavy metal behavior after the and of biosolid application is still unknown. In soils, heavy metals may be adsorbed via specific or non-specific adsorption reactions. Iron oxides and organic matter are the most important soil constituents retaining heavy metals. The pH, CEC and the presence of competing ions also affect heavy metal adsorption and speciation in soils. In solution, heavy metals can be present either as free-ions or complexed with organic and inorganic ligands. Generally, free-ions are more relevant in environmental pollution studies since they are readily bioavailable. Some computer models can estimate heavy metal activity in solution and their ionic speciation. Thermodynamic data (thermodynamic stability constant), total metal and ligand concentrations are used by the GEOCHEM-PC program. This program allows studying heavy metal behavior in solution and the effect of changes in the conditions, such as pH and ionic strength and the application of organic and inorganic ligands caused by soil fertilization.
Manual transportation within the plot and physical damages to bananas
Authors: Magalhães Mário Jorge Maia de , Abrahão Roberto Funes , Leal Paulo Ademar Martins
Published: April 2005

The manual transportation of banana bunches within plots provokes physical damages to fruits compromising their quality. To assess the influence of the distance banana bunches travel on the shoulders of harvesters within the plot, on the incidence of physical damages present on the peel of fruits of the Nanicão cultivar, two experiments were carried out in the Vale do Ribeira region (SP), in sites with slope < 1%. Each experiment divided the plot in different distance bands, two of which were included in this study: one located far away from the collection roads (30-50 m and 80-100 m distance bands) and another in an intermediate position (70-80 m and 130-150 m distance bands). For each distance band, six banana bunches of 36 mm gauged fruits were randomly sampled. Four banana hands were cut from the middle region of each bunch and ten fruits were assessed per hand, totaling 240 fruits per treatment. Bunches were harvested at the same maturity degree and those served as control were not transported. A total of 1440 fruits was assessed in the two experiments. The physical damages on the fruit surface were graded on a scale with 6 divisions: 0-0.25 cm²; 0.25-0.5 cm²; 0.5-1.0 cm²; 1.0-1.5 cm²; 1.5-2.0 cm²; 2.0-2.5 cm². The bunches transported on the shoulders of harvesters on distances over 70 m suffered increased (P < 0.01) damaged area. Most damages presented areas up to 0.5 cm².
Organic matter quality in a soil cultivated with perennial herbaceous legumes
Authors: Canellas Luciano Pasqualoto , Espindola José Antonio Azevedo , Rezende Carlos Eduardo , Camargo Plínio Barbosa de , Zandonadi Daniel Basílio , Rumjanek Victor Marcos , Guerra José Guilherme Marinho , Teixeira Marcelo Grandi , Braz-Filho Raimundo
Published: April 2005

Using herbaceous legumes in agricultural systems yields great quantities of plant residues, allowing changes in soil organic matter quality and content over the years. This study was conducted on an Ultisol, at Seropédica, RJ, Brazil, to evaluate the effects of different perennial herbaceous legumes on soil organic matter quality. A factorial scheme with three replications was used to evaluate the species: forage groundnut cv. BR-14951 (Arachis pintoi), tropical kudzu (Pueraria phaseoloides), and siratro (Macroptilium atropurpureum). After the first cut, each plot was divided into two subplots; plants were cut and left on the soil surface or cut and removed. Soil samples of a closed area covered by spontaneous vegetation (mainly C3 plants) or by Panicum maximum were also analysed. Samples were collected from two layers (0-5 and 5-10 cm), processed for the fractionation of organic matter and the evaluation of structural characteristics of humic acids (HA). Evaluated legumes did not change total organic carbon contents, but promoted HA accumulation in the superficial soil layer. Humic acids may be used as indicators of the management effects on soil organic fractions, because there was significant incorporation of carbon and nitrogen derived from the legume residues, even for the short experimentation time (28 months). Residue management did not modify quantitative aspects of the distribution of the humified organic matter, but promoted, however, a higher condensation degree of humic acids evaluated by the elementary composition, IR and fluorescence spectroscopy.
Kinetics of phosphorus uptake and root morphology of local and improved varieties of maize
Authors: Machado Cynthia Torres de Toledo , Furlani Ângela Maria Cangiani
Published: April 2005

Interspecific and intraspecific differences in the efficiency of utilization of soil phosphorus (P) are explained, in part, by plant morphological and physiological variations, which characterize the plant for nutrient acquisition. As part of a study on maize genotypes characterization for P-uptake and use efficiency, kinetic parameters of P uptake and root morphological characters were evaluated for six local and improved maize varieties, grown in nutrient solution. The kinetic parameters related to P influx were: maximal transport rate (Vmax), the Michaelis-Menten constant (Km), and the external concentration when net uptake is zero (Cmin). Measured root morphological characters were: root length, radius, and surface area. Shoot and root dry matter yield and the P content in these parts were also determined. Diferences among varieties were observed in the kinetic parameters Vmax and Km, root length and in root/shoot dry matter ratio. Lower Km values were better indicatives of P uptake ability of the varietes and were significantly correlated to higher dry matter production and P-efficiency index.
Muskmelon seed priming in relation to seed vigor
Authors: Nascimento Warley Marcos , Aragão Fernando Antônio Souza de
Published: April 2005

A number of important factors may affect seed priming response, including seed quality. Effects of seed vigor on seed priming response were investigated using seed lots of two muskmelon (Cucumis melo L.) cultivars. Seeds of muskmelon, cvs. Mission and Top Net SR were artificially aged at 43°C for 0, 20 and 40 hours. Seeds were primed for six days in darkness at 25°C in KNO3 (0.35 mol L-1) aerated solution. Aged seeds germinated poorly at 17°C. Priming increased germination rate at 17 and 25°C and germination percentage at 17°C. An interaction effect on germination performance between vigor and priming was observed, especially at low temperature. Priming increased germination performance in seeds of low vigor, and the response was cultivar dependent.
Hydrocyclone for pre-filtering of irrigation water
Authors: Soccol Olívio José , Botrel Tarlei Arriel
Published: April 2005

The use of water containing suspended sediments causes serious problems to irrigation systems. Choosing the right filtering system type and capacity is essential to avoid increases in operational and maintenance costs of irrigation resulting from the need for cleaning and frequent component replacing. Pre-filters, such as the hydrocyclone, are important for their significant capability of retaining particles suspended in the water. Data on hydrocyclones performance for pre-filtering of irrigation water can be found in the literature, but research data in Brazil are scarce. Therefore, four Rietema type hydrocyclones (50 mm diameter) were constructed, one with circular-end and the other three presenting rectangular-end feeding tubes. The evaluation of hydrocyclones performance was conducted by using suspensions of fine sand and clay soil particles under varied pressure differentials. The comparison criteria were the discharge and the separation capability, given by total efficiency and reduced total efficiency. The hydrocyclone with circular-end feeding tube presented the highest indexes for the adopted criteria, considering sand and soil suspensions.
Performance of Santa Ines lambs fed diets of variable crude protein levels
Authors: Rocha Márcia Helena Machado da , Susin Ivanete , Pires Alexandre Vaz , Fernandes Jr. Jalme de Souza , Mendes Clayton Quirino
Published: April 2005

Differences among dietary protein levels suggested in the literature point out to the need for better evaluation of protein requirements of growing lambs, raised in drylot on a high-concentrate diet. This study evaluates the influence of crude protein (CP) levels in high concentrate diets on performance and carcass traits of ram lambs, confined for 56 days. Forty eight (48) Santa Ines lambs (initial body weight 18.4 ± 0.4 kg; 86 ± 2 days old) were fed 4 experimental diets containing 14, 16, 18 or 20% CP, in a completely randomized block design. Diets consisted of 80% concentrate and 20% sugarcane bagasse. There were no differences in average daily gain: values of 228, 220, 230 and 231 g d-1 were obtained for diets containing 14, 16, 18 and 20% CP, respectively. There were no differences in dry matter intake and feed conversion: values were 1.03; 1.02; 1.08 and 1.10 kg d-1; 4.19; 4.28; 4.35 and 4.44 kg DM kg-1 gain for diets with 14, 16, 18 and 20% CP, respectively. Plasma urea nitrogen concentrations increased linearly as diets contained more CP. There were no differences in carcass traits.