Showing papers in "Scientia Agricola in 2000"
TL;DR: In this paper, a software for adjustment of soil water retention curves (SWRC) is presented, using twelve models found in the literature, and the adjustment of SWRC is described.
Abstract: A software for the adjustment of soil water retention curves (SWRC) is presented, using twelve models found in the literature.
144 citations
TL;DR: In this paper, the authors studied the methodology of the accelerated aging test to evaluate the physiological quality of carrot seeds and the efficiency of using saturated salt solution for water uptake by seeds during the accomplishment of the test.
Abstract: The objective of the present work was to study the methodology of the accelerated aging test to evaluate the physiological quality of carrot (Daucus carota L.) seeds and the efficiency of using saturated salt solution for water uptake by seeds during the accomplishment of the test. Four lots of carrot seeds cv. Brasilia were tested for germination, seedling emergence, electrical conductivity and accelerated aging (41°C; 48, 72 and 96h; with and without the use of saturated solution of NaCl). Accelerated aging (with and without salt) ranked different vigor levels among seed lots, as well as seedling emergence. It was concluded that, among the accelerated aging protocols studied, the period of 72h, with the use of the saturated solution of NaCl, is considered appropriate to assess the physiological quality of carrot seeds, cv. Brasilia. It was also observed that seed water content after the saturated salt accelerated aging test was lower and more uniform, thus showing advantages in relation to the conventional procedure.
103 citations
TL;DR: Avaliou-se o desempenho produtivo de tres cultivares de soja, pertencentes a diferentes ciclos de maturacao, instalados in epocas de semeadura normal, tardia e safrinha as discussed by the authors.
Abstract: Avaliou-se o desempenho produtivo de tres cultivares de soja, pertencentes a diferentes ciclos de maturacao, instalados em epocas de semeadura normal, tardia e safrinha. Cada epoca constituiu experimento individual delineado em blocos casualizados num fatorial 3 x 3 (tres cultivares: IAC-12, IAC-17 e IAC-19; tres densidades de plantas: 10, 20 e 30 plantas.m-1), com tres repeticoes. Os componentes da producao, destinados a avaliacao do rendimento, numero total de vagens por planta e numero total de graos por planta, foram determinados em 10 plantas aleatorias na parcela util. A massa de 1000 graos e o rendimento de graos foram determinados com base na populacao final de plantas na area util de cada parcela. Concluiu-se que: os caracteres componentes do rendimento apresentam variacoes entre eles, com efeito de compensacao, no sentido de uniformizar o rendimento de graos, entre cultivares, densidades e epoca de semeadura; o cultivar IAC-19 apresenta melhor desempenho para rendimento de graos em epoca de semeadura safrinha, independente das densidades; a epoca de semeadura e o fator que mais influencia no rendimento de graos.
94 citations
TL;DR: Pre-breeding is a promising alternative to link genetic resources and breeding programs for maize and several aspects for maize such as concept, importance, methods and results are discussed.
Abstract: Activities related to genetic resources are characterized by high cost and long term return. Thus the conservation of genetic variability for the future and the efficient utilization of available accessions are two important goals to be attained. However, the low utilization of germplasm banks is not restricted to Brazil but to other developing countries as well. Therefore, pre-breeding is a promising alternative to link genetic resources and breeding programs. Several aspects for maize are discussed such as concept, importance, methods and results. Problems to be investigated and suggestions are also presented.
93 citations
TL;DR: In this paper, the authors estimate the number of people that could be served each year by this biomass if its energy was converted into electricity, based on logical assumptions and appropriate data.
Abstract: Brazil is a developing tropical country with abundant biomass resources. Sugar cane (Saccahrum spp.) is primarily produced to obtain sugar and alcohol. Presently sugar cane is burned before harvest. If the cane were not burned before harvest, the trash (tops and leaves) could be collected and burned to produce steam to generate electricity, or be converted into alcohol fuel and decrease the severe air pollution problems caused by sugar cane burning. Based upon logical assumptions and appropriate data, we estimate the number of people that could be served each year by this biomass if its energy was converted into electricity. From trash and bagasse, 7.0x106 and 5.5x106 people y-1 could be served, respectively.
88 citations
TL;DR: Screening fourteen Trichoderma strains against Rhizoctonia solani revealed that all T. harzianum strains interacted with R. solani, inhibiting the mycelial growth and Penetration of host cells was apparently accomplished by mechanical activity.
Abstract: Rhizoctonia solani causes serious diseases in a wide range of plant species. The fungus Trichoderma has been shown to be particularly effective in the control of the pathogen. Thus, this research was carried out to screen fourteen Trichoderma strains against R. solani in vitro. All strains tested inhibited the growth of R. solani. Three T. koningii strains produced toxic metabolites with strong activity against R. solani, inhibiting the mycelial growth by 79%. T. harzianum, Th-9 reduced the viability of sclerotia of R. solani by 81.8% and T. koningii, TK-5 reduced by 53%. Electron microscopic observations revealed that all T. harzianum strains interacted with R. solani. Th-9 grew toward and coiled around the host cells, penetrating and destroying the hyphae. Penetration of host cells was apparently accomplished by mechanical activity.
86 citations
TL;DR: In this article, a sistema de manejo de solo (plantio direto, grade aradora, escarificacao profunda, and aracaula profunda) associados with tres niveis of adubacao fosfatada e potassica was evaluated.
Abstract: O sistema de plantio direto tem sido adotado expressivamente por agricultores do cerrado brasileiro. Contudo, seu uso continuado em regioes tropicais, com insuficiencia de cobertura do solo e sucessivas adubacoes superficiais, pode resultar em alteracoes nos parâmetros do solo, como compactacao e acumulo de nutrientes na superficie, e na baixa expressao do potencial produtivo das culturas. O presente estudo teve como objetivo principal verificar o efeito de quatro sistemas de manejo de solo (plantio direto; grade aradora; escarificacao profunda e aracao profunda) associados com tres niveis de adubacao fosfatada e potassica (sem adubacao, recomendacao oficial e equivalente a exportacao pelas colheitas) sobre o rendimento das culturas do milho, soja, feijao e arroz em area submetida a plantio direto durante oito anos. Os experimentos com soja, milho, arroz e feijao foram conduzidos em um Latossolo Roxo eutrofico no esquema de faixas e delineamento de blocos completos casualizados, com quatro repeticoes. Avaliou-se ainda o rendimento de graos. Nao houve resposta da soja aos diferentes manejos do solo nem aos niveis de adubacao. Ja a aracao profunda resultou nos maiores rendimentos de milho, arroz e feijao, sendo intermediarios os efeitos devidos a escarificacao. Exceto para o feijao, nestas culturas tambem nao se verificou efeito da adubacao.
71 citations
TL;DR: Results indicated that these hybrids attend the Sao Paulo market exigence, and became the 'COMPOSTO IAC-27' cultivar.
Abstract: Este experimento foi conduzido em Monte Alegre do Sul, SP, de 1995 a 1997, com o objetivo de se obter um cultivar de maracuja amarelo, homogeneo quanto a qualidade de fruto, de alta produtividade e bem aceito pelo mercado. Estudou-se o comportamento de 8 hibridos, obtidos em sucessivos ciclos de selecao recorrente, a partir de individuos pre-selecionados em pomares comerciais ou bancos de germoplasma. Foram avaliados desenvolvimento vegetativo, tipos de flores, periodo de florescimento e frutificacao e produtividade. A analise qualitativa dos frutos incluiu peso, diâmetro longitudinal e transversal dos frutos; proporcao da polpa e sua coloracao, teor de solidos soluveis totais (SST), numero de sementes e classificacao comercial. A melhor combinacao desses fatores foi obtida em 'IAC-3', 'IAC-5' e 'IAC-7', que produziram frutos ovais, compactos, com elevada proporcao de polpa alaranjada-intensa, peso medio de 170 a 218g, SST medio de 15°Brix e 51% de rendimento em polpa. A produtividade media foi de 45 a 50 t/ha/ano, com polinizacao manual, resultando em frutos do tipo 2A e 3A, com dimensoes externas de 8,8 x 7,3 cm e 400 sementes/fruto. Essas tres selecoes atenderam as atuais exigencias do mercado, sendo reunidas no 'COMPOSTO IAC-27', lancado como cultivar, em 1998.
63 citations
TL;DR: The objective of this work was to quantify the genetic diversity among cassava folk varieties as well as to examine the distribution of the genetic Diversity among varieties of different origin and type.
Abstract: The objective of this work was to quantify the genetic diversity among cassava folk varieties as well as to examine the distribution of the genetic diversity among varieties of different origin and type. Fifty-four cassava varieties were chosen from 4 Brasilian regions: 45 of the Amazon basin (23 from River Negro, 6 of the River Branco and 16 of the River Solimoes) and 9 of the south coast of the Sao Paulo State, Brazil. The modern variety Mantiqueira was also included as a reference. Among these, 38 were bitter varieties and 17 sweet. Three different types of DNA markers were used: RAPD (randomly amplified polymorphic DNA), AFLP (amplified fragment length polymorphism) and microsatellites. Analysis of the results consisted of a description of band patterns, a calculation of similarity indexes (Nei & Li) and a principal coordinate analysis (PCoA) for each marker type. Heterozygosity, diversity indexes (DI, Weir) and genetic differentiation coefficients (GST) were calculated for the microsatellite loci.Genetic variability was more concentrated within regions, then among regions (GST = 0.07). Mean heterozygosity was 56%. Mean similarity indexes were dependent on the marker used: S = 0.89 for RAPD, S = 0.85 for AFLP and S = 0.59 for microsatellites. PCoA analysis revealed groups, distinguishing bitter from sweet varieties.
63 citations
TL;DR: Patterns of tiller population density, tiller appearance and mortality rates, proportion of flowering tillers and herbage dry matter accumulation for Cynodon spp.
Abstract: The aim of this study was to verify patterns of tiller population density, tiller appearance and mortality rates, proportion of flowering tillers and herbage dry matter accumulation for Cynodon spp. (cv. Tifton 85). Treatments corresponded to four "steady state" conditions characterised by sward surface heights of 5, 10, 15, and 20 cm, maintained by sheep grazing under continuous stocking and variable stocking rate. Treatments were allocated to experimental units (400 m2 each) according to a completetely randomised block design with four replication. Tillering evaluations consisted of tagging and counting all tillers present and new tillers emerging within two 15 cm diameter plastic rings (PVC) per experimental unit. Herbage accumulation was measured using exclosure cages rotated every three weeks. There was a time effect (P 0,10).
55 citations
TL;DR: In this paper, the presence of heavy metals in sewage sludge amended soils can cause concern due to the possibility of the absorption of these metals by plants growing on these soils, and the availability of Cd, Cr, Cu, Ni, Pb and Zn to corn plants in soils continuously treated with biosolids (sewage sludge) was evaluated by an experiment performed in 0.5 m3 pots with a dystrophic Typic Hapludox (LAd) and a dy-strophic Rhodic Haus (LVd).
Abstract: The presence of heavy metals in sewage sludge amended soils can cause concern due to the possibility of the absorption of these metals by plants growing on these soils. The availability of Cd, Cr, Cu, Ni, Pb and Zn to corn plants in soils continuously treated with biosolids (sewage sludge) was evaluated by an experiment performed in 0.5 m3 pots with a dystrophic Typic Hapludox (LAd) and a dystrophic Rhodic Hapludox (LVd). The adopted statistical design was random blocks with four treatments (LAd+sludge, LAd, LVd+sludge and LVd) and four replications. Biosolids from SABESP-Barueri treatment plant (Sao Paulo/Brazil) were applied every two months to the soils until one year before planting corn, totallizing 388 Mg ha-1. Before sowing the corn the control treatments (without sludge addition) received lime and NPK fertilizers. During crop growth soils with biosolids were also fertilized with NPK. At harvest corn plantlets were divided into: diagnose leaf, old leaves, stem, sheath, grains, corn cob and straw. This material was submitted to nitro-percloric digestion, and metals were quantified by conventional flame atomic absorption spectrophotometry. The successive biosolid applications, at rates of 78 Mg ha-1 each, did not increase corn yield, however plant availability was observed for Cu and Zn. No plant availabilities for Cd, Cr, Mn, Ni and Pb were observed.
TL;DR: A fenologia foi associada a o numero relativo de graus-dia, onde se observou uma relacao linear as discussed by the authors.
Abstract: Com os objetivos de avaliar o efeito da temperatura media do ar no rendimento de graos e de prever a epoca de ocorrencia dos estadios fenologicos da cultura de milho em funcao da soma calorica, foi conduzido um experimento de campo utilizando tres hibridos, com diferentes exigencias termicas, em tres diferentes epocas de semeadura. Para estimativa do rendimento de graos foram determinados seus diferentes componentes, onde se observou um decrescimo do rendimento com aumento da temperatura em funcao das epocas de semeadura utilizadas. A fenologia foi associada ao numero relativo de graus-dia, onde se observou uma relacao linear. Ha uma temperatura media do ar correspondente ao maximo rendimento de graos, e os estadios fenologicos da cultura podem ser previstos atraves do conhecimento previo da serie historica de temperatura da localidade e da soma calorica requerida para o ponto de maturidade fisiologica.
TL;DR: In this paper, the neutralization power of lime would be compatible with the residue used to produce steel, as a function of pH, H+Al, and Ca+Mg contents on acid soils in the Cerrado region, for sugar cane cultivation.
Abstract: The neutralizing components of steel will residue are linked with high energy, combined with the presence of several metallic elements; these characteristics interfere in the chemical evaluation of their neutralization power. The aim of this study was to evaluate if the neutralization power of lime would be compatible with the residue used to produce steel, as a function of pH, H+Al, and Ca+Mg contents on acid soils in the Cerrado region, for sugar cane cultivation. This study was performed in 20 dm3 pots in a greenhouse, with Acrustox and Quartzipsamment soils, in two sucessive cultivations of sugar cane (first cutting and second cutting), harvest was 210 days after ammendments incorporation, for each cultivation. Treatments constituted of two corrective agents: limestone and steel will residue, in two levels of application, as follows: level 1 = the rate to increase V to 50%, and level 2 = double of the rate necessary to increase V to 50%. At the end of each cultivation, soils were sampled and analysed chemicaly. The reactivity of the steel will residue depends on the soil class type. The efficiency of the steel will residue based on the power of neutralization adopted for limestone was not sufficient to allow evaluation of the quantity necessary of the product for the correction of soil acidity, suggesting the necessity of further studies.
TL;DR: The effect of aqueous extracts of Trichilia pallida leaves and twigs on the development and oviposition of Tuta absoluta was evaluated, and no ovicidal activity was detected with T. pallida leaf extract.
Abstract: The effect of aqueous extracts of Trichilia pallida leaves and twigs on the development and oviposition of Tuta absoluta was evaluated. Larvae of T. absoluta were fed with tomato leaves (Lycopersicon esculentum, cv. Santa Clara) previously treated with extracts at concentrations of 0.1; 1.0 and 5.0%. The effects of the leaf extracts at 1.0 and 5.0% were evaluated on eggs of this pest. Free-choice non-preference tests for oviposition were also conducted with treated and non-treated tomato leaves with the extract at concentration of 5.0%. Leaf and twig extracts affect the insect development mainly at the larval stage, increasing the length and reducing viability of this stage. The activity of the leaf extract is greater than that of the twig extract with the reduction of larval viability to approximately 20% at concentration of 1.0%. No ovicidal activity was detected with T. pallida leaf extract at 5.0%, however, the treated substract can become less attractive for oviposition.
TL;DR: A methanolic extract from neem seed kernels, obtained using the Soxhlet apparatus was used to study the mortality of eggs and larvae of Tuta absoluta and to evaluate of the ovicidal effect.
Abstract: A methanolic extract from neem seed kernels, obtained using the Soxhlet apparatus was used to study the mortality of eggs and larvae of Tuta absoluta (Lepidoptera: Gelechiidae) and to evaluate of the ovicidal effect. Eggs 24 hours after oviposition were counted and sprayed with the extract at the concentrations of 1000, 500, 250, 125 and 62.5 mg L-1. Controls were sprayed with water and methanol. The experiment was conducted in laboratory conditions at 25±2°C; UR 50±10% and 12 h of photophase. Incubation period for all treatments, including controls, was four days on the average. The extract did not affect the viability of eggs, although the values varied between of 51.7% the 80.6%. Larvae recently hatched from eggs were placed in glass tubes containing a tomato leaflet previously immersed for five seconds into the extract, at concentrations of 2000, 4000, 6000 and 8000 mg L-1 and conditioned on BOD at 27±1°C; 65±10% RH and 12 hours of light. By the fourth day after treatment the extract caused mortalities of 82, 68, 94.7 and 100%, respectively. By the sixth day, all concentrations caused 100% mortality of the larvae. The controls with water and methanol presented mortalities of 4 and 8%, respectively.
TL;DR: The bioactivity of aqueous extracts of Melia azedarach leaves and Trichilia pallida twigs on the silverleaf whitefly Bemisia tabaci (Gennadius) biotype B, reared on tomato is determined.
Abstract: The silverleaf whitefly is today one of most important pests of tomato. The use of botanical extracts to control this insect is an interesting technique, but more research about it should be carried out. The objective of this work was to determine the bioactivity of aqueous extracts of Melia azedarach leaves and Trichilia pallida twigs on the silverleaf whitefly Bemisia tabaci (Gennadius) biotype B, reared on tomato. Extracts were applied to eggs, and mortality and duration of egg and nymphal stages were evaluated in two experiments. In the first experiment, extracts were tested at concentrations of 1 and 2% (w/v) and in the second experiment the concentration of 3% was added. The ovicidal effect was observed in all treatments. The highest value was obtained with the extract of T. pallida at 3% (52.32%). For the other treatments the mortality ranged between 16 and 37%. The extracts applied on eggs presented low effect on nymphs. With exception of T. pallida at 2%, in the first experiment, where the nymphal mortality was 26.42%, in the other treatments the values were lower than 16%. The duration of egg and nymph periods were not affected by the extracts.
TL;DR: The effect of seed vigor on the growth of two cultivars of cultivated black oats (Avena strigosa Schreb) was evaluated, as well as to verify possible interactions with plant population, to verify a compensatory effect of the plant population on dry matter production.
Abstract: This study was carried out in Capao do Leao, RS, Brazil, with the objective of evaluating the effect of seed vigor on the growth of two cultivars of cultivated black oats (Avena strigosa Schreb), as well as to verify possible interactions with plant population (150, 300 and 450 pl m-2). Seed vigor and plant population affected dry matter production during the vegetative period. The effects were reduced progressively in the growing season, with no more difference after anthesis. The extreme levels of seed vigor and plant population produced differences in dry matter yield of 410 kg ha-1 and 480 kg ha-1, respectively, at the 75th day after emergence, these effects were due to differences in crop growth rates. A compensatory effect of the plant population on dry matter production was verified, so that the effect of low seed vigor could be compensated by an increase in plant population; the lower the seed vigor level, the greater was the plant population required. High vigor seeds also compensated the effects of low plant populations.
TL;DR: The reproductive capacity of the endoparasitoid Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hym.: Eulophidae) on lepidopteran host pupae was dealt with, with significant difference in the progeny emergence.
Abstract: This paper deals with the reproductive capacity of the endoparasitoid Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hym.: Eulophidae) on lepidopteran host pupae: Diatraea saccharalis F. (Pyralidae), Anticarsia gemmatalis Hubner, Spodoptera frugiperda J. E. Smith and Heliothis virescens Fabricius (Noctuidae). The experiments were carried out under control (25 ± 1°C, 70 ± 10% RH, 14-hour photofase). Parasitism did not differ significantly among host species. However there was significant difference in the progeny emergence, with the highest number for S. frugiperda (130.6 ± 5.8 offsprings/pupa) and lowest for H. virescens (105.3 ± 2.9 offsprings/pupa). However no significant difference between D. saccharalis (122.9 ± 5.5 offsprings/pupa) and A. gemmatalis (118.3 ± 6.5 offsprings/pupa) was observed.
TL;DR: The nodulating cultivar with inoculation or in soil with efficient native population can eliminate the N top dressing with no decrease in yield.
Abstract: Avaliando o comportamento do feijoeiro inoculado com cinco estirpes de Rhizobium tropici e a adubacao mineral com nitrogenio, sobre alguns fatores relacionados a sua produtividade, utilizou-se um delineamento experimental de blocos ao acaso, com oito tratamentos constituidos pela inoculacao do feijoeiro cultivar IAC Carioca com cinco estirpes de Rhizobium tropici (CIAT 899 - estirpe referencia; F35; F54; F81 e CM255), dois controles sem inoculacao sendo um adubado com N na semeadura e em cobertura e outro sem adubacao e um cultivar nao nodulante (NORH 54) adubado; com seis repeticoes. Avaliaram-se: numero de nodulos por planta; massa de material seco da parte aerea; teor de N nas folhas; numero de vagens por planta; numero de graos por planta; numero de graos por vagem; peso de 100 graos e produtividade de graos. A inoculacao de estirpes eficientes de Rhizobium em cultivar nodulante de feijoeiro, ou o cultivo deste em solos com populacao nativa eficiente, pode possibilitar a nao utilizacao de nitrogenio em cobertura na cultura do feijoeiro, sem afetar a produtividade.
TL;DR: In this paper, spray deposition and losses were evaluated using 2% KCl and NaCl solutions in air-assisted and conventional non-assisted sprayers, respectively, for the soybean crop.
Abstract: The spray deposition and losses of pesticide application were evaluated for the soybean crop. In this study two sprayers were used: the air-assisted sprayer (Vortex-Jacto) and the conventional non-assisted sprayer (Condor M12-Jacto), both with API 110-1.5 flat fan nozzles operating at 30 psi working pressure, with 0.5 m spacing on the boom. Volume rates were 100 L ha-1 for both equipments. A completely randomized experiment with four replicates was carried out in the field. For all treatments, the ground speed was 6 km h-1 and boom height was 0.40 m above canopy. Spray deposition and losses were evaluated using 2% KCl and NaCl solutions in air-assisted and conventional non assisted sprayers. Deposition evaluations were performed on leaves from the upper, medium and lower parts of the soybean plant. Spray losses to the soil were evaluated using artificial targets (square wood board) that were distributed on the soil surface at intervals of 3 m from each other. Drift was evaluated through these targets and pipe cleaners fixed on rods placed at the left and right sides at the crop. There were no significant differences in the deposition for both equipments in the upper parts of the plants, but there were differences in the medium and lower parts, showing an advantage of the air-assisted sprayer. Drift and losses were larger for the conventional non assisted sprayer at similar meteorological conditions.
TL;DR: In this article, the authors present a critical appraisal on the use of the "broken-line" model in the analysis of growth data derived from a dietary protein requirement assay with "tambaqui" ( Colossoma macropomun).
Abstract: The growth of the fish industry, as a result of the development of aquaculture, requires specific knowledge on nutritional requirements of cultured fish and shellfish species. These requirements can be influenced by factors as diverse as fish size, feed composition, feeding practices, system management, as well as by the statistical and mathematical tools utilized in the analysis of fish nutritional research data. This paper presents a critical appraisal on the use of the 'broken-line' model in the analysis of growth data derived from a dietary protein requirement assay with 'tambaqui' ( Colossoma macropomun). Results show that the 'broken-line model analysis', as performed by a linear regression procedure, is simple, fast and reliable, suitable for the analysis of fish growth data. Nevertheless, the model may underestimate values determined
TL;DR: Os resultados permitem inferir that a exigencia nutricional do tucunare pode ser suprida por uma racao contendo entre 8 e 9 kcal de ED g-1 de PB, ou seja, 37 a 41% of PB e 3.500 kcal of ED kg-1 of alimento.
Abstract: O objetivo deste estudo foi avaliar o efeito da relacao energia:proteina no desempenho e composicao corporal do tucunare. Para tanto, 196 alevinos de tucunares (Cichla sp.), condicionados a aceitar alimentos secos, com peso medio vivo de 10 g, foram estocados em gaiolas de tela de volume igual a 25 L, alojadas em 16 caixas de cimento amianto com volume de 500 L, instaladas em uma estufa e abastecidas por um sistema fechado de recirculacao de agua. Os peixes foram alimentados ad libitum com racao seca em duas refeicoes diarias, por um periodo de 65 dias com quatro racoes isoenergeticas (3.500 kcal de ED kg-1 de racao), com niveis de proteina bruta de 41%, 37%, 33% e 30% de forma a obter uma relacao ED:PB de 8, 9, 10 e 11 kcal de ED g-1 de PB, estabelecendo-se um delineamento experimental inteiramente casualizado com 4 tratamentos e 4 repeticoes. No inicio do experimento um lote de peixes foi sacrificado para determinacao dos teores corporais de proteina, gordura, agua e materia mineral. No final do periodo experimental, foram sacrificados lotes de peixes de cada tratamento para nova analise de composicao corporal. Os dados obtidos foram submetidos a analise de variância utilizando-se do software SAS, e aplicando-se regressao polinomial para avaliar o efeito das relacoes ED:PB nas variaveis analisadas ao nivel de 5% de probabilidade. Os resultados permitem inferir que a exigencia nutricional do tucunare pode ser suprida por uma racao contendo entre 8 e 9 kcal de ED g-1 de PB, ou seja, 37 a 41% de PB e 3.500 kcal de ED kg-1 de alimento.
TL;DR: The first count test, accelerated aging and electrical conductivity at 4 and 24 hours were reliable to detect differences in vigor of pepper seed lots, and Electrical conductivity test at 4 hours was more reliable for the classification of lots by vigor.
Abstract: O objetivo deste trabalho foi avaliar a eficacia de diferentes metodos para a determinacao da qualidade fisiologica de sementes de pimentao (Capsicum annuum L.), cv. All Big, procurando obter informacoes que possam indicar opcoes de utilizacao nos programas de controle de qualidade, bem como tornar possivel, atraves de testes de laboratorio, a identificacao do potencial de emergencia das plântulas em campo. Para tanto, foram avaliadas sementes de quatro lotes, pelos testes de germinacao, primeira contagem de germinacao, condutividade eletrica apos quatro e 24 horas, envelhecimento acelerado, frio em rolo de papel sem solo, emergencia das plântulas em campo e grau de umidade. Os resultados indicaram que os testes de primeira contagem de germinacao, envelhecimento acelerado e condutividade eletrica durante quatro e 24 horas de embebicao das sementes sao os mais indicados para a separacao dos lotes de sementes de pimentao em diferentes niveis de vigor. A condutividade eletrica avaliada apos quatro horas de acondicionamento das sementes mostrou-se o metodo mais eficiente para a estratificacao dos lotes em funcao do vigor.
TL;DR: Most of the genetic variability of cassava landraces was restricted within the geographical regions, which confirmed the evolutionary dynamic model for this species.
Abstract: The management practices used in authoctonous agriculture with landraces of cassava (Manihot esculenta Crantz) play an important role in the in situ conservation of genetic resources The objective of this work was to analyze the genetic variability present in 141 landraces of cassava, collected in gardens of different geographical regions of Brazil using isozyme techniques visualized by starch gel electrophoresis Eleven enzymatic systems were analised Of the 15 polymorphic loci evaluated the observed mean heterozigosity was 0354 GST estimates presented a value of 880% for the genetic variability between regions In cluster analysis, three distinct groups were observed: the first group was formed by the gardens of the Amazon; the second group consisted of gardens of Sao Paulo State; and the third group was formed by the gardens of the Xingu region Most of the genetic variability of cassava landraces was restricted within the geographical regions, which confirmed the evolutionary dynamic model for this species
TL;DR: The authors avaliar o efeito da adubacao NPK sobre o desenvolvimento de mudas de laranjeira "Valencia" (Citrus sinensis) sobre a porta-enxerto de limoeiro 'Cravo' (C. limonia) em vasos com substrato de Pinus, vermiculita e perlita.
Abstract: O objetivo deste trabalho foi avaliar o efeito da adubacao NPK sobre o desenvolvimento de mudas de laranjeira 'Valencia' (Citrus sinensis) sobre o porta-enxerto de limoeiro 'Cravo' (C. limonia) em vasos com substrato de casca de Pinus, vermiculita e perlita. Utilizou-se um esquema de fatorial fracionario (1/5)53 com um delineamento em blocos ao acaso. Os tratamentos consistiram em 5 doses (em g por planta) de N: 1,25; 6,25; 11,25; 16,25; 21,25; 5 doses de K: 0,42; 3,75; 6,22; 9,34; 12,45; e 5 doses de P: 0,19; 0,89; 1,59; 2,29; 2,99. O N e o K foram fornecidos semanalmente, sendo 37,5% da dose para o porta-enxerto. O P foi fornecido totalmente no plantio. Avaliaram-se a producao de material seco das folhas, raizes, caule, parte aerea e total; area foliar, relacao raizes/parte aerea; altura de plantas; volume radicular, relacao area foliar/material seco para os porta-enxertos e as mudas, e o diâmetro do caule para os porta-enxertos. Funcoes de resposta foram ajustadas e os niveis de nutrientes foram calculados. Os resultados mostraram que as doses de fertilizantes que levaram as melhores respostas para producao de mudas de laranjeira 'Valencia'/'Cravo' sobre o porta-enxertos de limoeiro 'Cravo' foram: N, 9,85; P, 2,86; K, 7,99 g por plantas.
TL;DR: Em regioes tropicais a interacao genotipo x ambiente e uma importante fonte de variacao, estudo teve por objetivos avaliar em cruzamentos dialelicos as capacidades de combinacao e suas interacoes com ambientes e identificar as Combinacoes hibridas mais promissoras entre dez linhagens selecionadas
Abstract: Em regioes tropicais a interacao genotipo x ambiente e uma importante fonte de variacao. Esse estudo teve por objetivos avaliar em cruzamentos dialelicos as capacidades de combinacao e suas interacoes com ambientes e identificar as combinacoes hibridas mais promissoras entre dez linhagens selecionadas de milho (Zea mays L.). Os hibridos e as testemunhas foram avaliados no delineamento latice triplo 7 x 7 em tres ambientes durante o ano agricola de 1984/85. Nesse trabalho sao discutidos apenas os dados de producao de graos, os quais foram corrigidos para a variacao de estande (50 plantas por parcela) e umidade de grao (15,5%). Os dados de peso de espigas foram analisados utilizando-se uma adaptacao do metodo IV de Griffing, no qual os cruzamentos obtidos no dialelico completo sao avaliados em varios ambientes. A media dos hibridos considerando todos os ambientes variou de 6,6 t/ha a 10,3 t/ha. Na analise dialelica conjunta foram detectadas diferencas altamente significativas (P<0,01) para ambientes, capacidade geral de combinacao (CGC), capacidade especifica de combinacao (CEC) e para a interacao CGC x ambientes; a interacao CEC x ambientes nao foi significativa. Os resultados obtidos mostraram que tanto CGC como CEC foram importantes para esse conjunto de hibridos. Para os 13 hibridos mais produtivos as contribuicoes dos efeitos da CGC e CEC foram 56% e 44%, respectivamente. Por outro lado, tomando-se apenas os cinco melhores hibridos, os efeitos da CEC foram sempre mais expressivos em relacao aos efeitos da CGC, para cada hibrido e na media dos ambientes.
TL;DR: Pasteurization of a Brazil nut extract with and without addition of chemical preservatives and the storage of this product under refrigeration was performed to evaluate the conservation of this extract.
Abstract: Pasteurization of a Brazil nut extract with and without addition of chemical preservatives and the storage of this product under refrigeration was performed to evaluate the conservation of this extract. The product was monitored during 180 days by microbiological, physical and chemical analysis including titratable acidity and pH. Treatments with chemical preservatives were microbiologically stable and titratable acidity and pH were equilibrated. Absence of total and fecal coliforms demonstrated the pasteurization efficiency. It is concluded that the pasteurization is only a viable method for preservation of the Brazil nut extract when associated with chemical preservatives and refrigeration.
TL;DR: In this paper, a maquina foi operada in quatro velocidades de deslocamento (3, 6, 9, and 11,2 km/h) and em duas profundidades of adubacao (5 and 10 cm).
Abstract: Na semeadura mecanizada diversos fatores interferem no estabelecimento do estande de plantas e, com frequencia, na produtividade da cultura, destacando entre eles a velocidade de operacao da maquina no campo e a profundidade de deposicao do adubo no solo. Neste estudo avaliou-se o estabelecimento da cultura do milho, atraves de uma semeadora-adubadora provida de um dosador de sementes de disco horizontal perfurado e de quatro linhas de semeadura. A maquina foi operada em quatro velocidades de deslocamento (3, 6, 9 e 11,2 km/h) e em duas profundidades de adubacao (5 e 10 cm), num Latossolo Roxo eutrofico com plantio direto ha 12 anos. O numero de plantas de milho na linha de semeadura foi menor nas maiores velocidades de operacao da maquina. As sementes de milho que passaram pelo dosador de disco horizontal, nao foram sensivelmente danificadas nas velocidades de semeadura mais elevadas. A uniformidade dos espacamentos entre as sementes de milho na linha de semeadura foi considerada excelente para velocidade de 3 km/h, regular para 6 e 9 km/h e insatisfatoria para 11,2 km/h. As velocidades da semeadora-adubadora de ate 6 km/h e a adubacao realizada a 10 cm de profundidade propiciaram maiores estandes de plantas e numero de espigas por metro e foram responsaveis pelos maiores rendimentos de graos.
TL;DR: In this paper, a trabalho aimed at avaliar a concentracao de nutrientes of sete diferentes compostos orgânicos produced with bagaco de cana-de-acucar, capim napier, palha de cafe, and dejeto de suinos.
Abstract: Este trabalho objetivou avaliar a concentracao de nutrientes de sete diferentes compostos orgânicos produzidos com bagaco de cana-de-acucar, capim napier, palha de cafe e dejeto de suinos na forma liquida. Cada composto foi produzido com um ou mais residuos vegetais associados ao dejeto de suinos, sendo o bagaco de cana-de-acucar tambem associado ao gesso e ao superfosfato triplo. Foi utilizado o delineamento experimental de blocos casualizados, com tres repeticoes e sete tratamentos. Aos 120 dias, as amostras foram coletadas e analisadas quimicamente, para quantificacao, em espectrofotometro de plasma, de macro e micronutrientes presentes nos compostos orgânicos. A presenca do bagaco de cana-de-acucar, como unico residuo vegetal, possibilitou a producao de compostos orgânicos com menor valor de K, Mg, B e pH. A adicao de gesso e superfosfato triplo nao proporcionou melhorias significativas na qualidade do composto produzido com bagaco de cana-de-acucar e dejeto de suinos. Os compostos produzidos com palha de cafe apresentaram valores mais altos para K e pH. A combinacao de bagaco de cana-de-acucar com palha de cafe melhorou a qualidade dos compostos orgânicos e pode ser pratica promissora para a Zona da Mata Mineira, pois estes sao residuos facilmente encontrados na regiao. A concentracao de Cu, Fe e Zn, nos compostos produzidos nao ultrapassaram os limites de seguranca para sua utilizacao no solo.
TL;DR: In this paper, one soybean seed lot, cv. BRS-155, was separated into different sizes (6.75, 6.35, 5.95 and 4.75 mm) for determining the pattern of water uptake of soybean seeds and its relationship to their physiological potential.
Abstract: Water uptake of soybean seeds, depending on seed size, occur at different intensities and can be related to the physiological potential. With the purpose of determining the pattern of water uptake of soybean seeds and its relationship to their physiological potential, one soybean seed lot, cv. BRS-155, was separated into different sizes (6.75; 6.35; 5.95; 5.55; 5.15; 4.75 e 4.35 x 19 mm). Seed sizes 6.35; 5.55 and 4.75 mm were submited to a slow hydration (pre-conditioning) and dried to the original water content. Water uptake was evaluatad at 20oC in samples of 130 seeds distributed on a suspended wire-mesh screen inside a plastic box, with the addition of 20 ml of water. Initial water content was evaluated through drying, and the imbibition rate through weighting the seeds after 3, 6, 9, 12, 15, 18, 21 e 24 hours, in 5 replications. Physiological quality was evaluated through standard germination, accelerated aging and electrical conductivity tests, before and after water uptake. Among the different sizes, smaller seeds had lower physiological quality in the treatment without conditioning and, except for the accelerated aging without conditioning, medium seed size had the best performance. Water uptake was more intense in smaller seeds. In general, the smallest or largest seeds were of lower quality than those of medium size.