Embrapa Acre

Rio Branco, Brazil

Embrapa Acre

Rio Branco, Brazil
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This study had the objective to investigate the effects of gamma ray radiation on survival and proliferation of shoots from stem nodal segments and on the germination seeds passion fruit (Passiflora edulis f. flavicarpa). Stem segments explants (2cm) containing one axillary bud obtained from in vitropropagated seedlings of passion fruit were treated with γ-rays at dosages ranging from 10 to 60Gy and subsequently transferred to Murashige and Skoog (MS) medium supplemented with 4.0mg L-1 BAP. Seeds of passion fruit were irradiated with gamma rays at dosages ranging from 75 to 200Gy. Germination and survival of seedlings were measured after 30 and 60 days of transfer to MS medium, respectively. After 30 days of irradiation of stem segments it was observed 50% reduction in survival of explants and the number of shoots formed in vitro at 21.31 and 12.20Gy, respectively. The LD50 for seed germination is 160Gy, while for seedling survival is 125Gy. © 2015, Universidade Federal de Santa Maria. All rights reserved.

Santos R.S.,Embrapa Acre | Martinelli P.R.P.,Instituto Taquaritinguense Of Ensino Superior Ites
Ciencia Rural | Year: 2016

The aim of this study was to conduct a survey on nematodes associated with five cultivated fruit trees growing in the Agroforestry System (AFS) of the municipality of Oiapoque, Amapá, Brazil. Rhizosphere samples were collected from three points at the base of murici (Byrsonima sp.), soursop (Annona muricata), cupuaçu (Theobroma grandiflorum), passion fruit (Passiflora sp.) and peach palm (Bactris gasipaes) trees. Four species of phytonematodes were identified, namely Pratylenchus brachyurus, Helicotylenchus dihystera, Mesocriconema xenoplax and Rotylenchulus reniformis. The most prevalent and abundant species was R. reniformis, which was found in the rhizospheres of passion fruit, cupuaçu, soursop, and peach palm. The first record in Brazil of the nematode P. brachyurus, found in the roots of murici is reported here, and all of the nematode species identified here are the first records for fruit trees in the state of Amapá. © 2016, Universidade Federal de Santa Maria. All rights reserved.

da Silva R.F.,Emater Acre | Ascheri J.L.R.,Embrapa Agroindustria de Alimentos | de Souza J.M.L.,Embrapa Acre
Ciencia e Agrotecnologia | Year: 2010

Brazil nut (Bertholletia excelsa H.B.K.) is an important raw material. It constitutes a basic stable of the population living in the Amazon region. Due to high unsaturated lipid content, around 60 to 70% is highly perishable. Moreover, inadequate processing practices result in high broken or damaged nuts. The objective this work was to make a comparative study of the physicochemical properties, mineral contents, lipids, and essential amino acid profiles between intact and highly damaged Brazil nut. All samples were stored in the same conditions. Samples were stored during three months at room temperature. The mineral profile of both samples did not show significant variation in total contents. It resulted, however, in significant loss of unsaturated fatty acids such as oleic and linoleic acid, besides essential amino acid, specially lysine. This fact can imply a reduction in the nutritional and sensory properties of the nut.

de Souza Gomes Guarino E.,Embrapa Acre | Scariot A.,Embrapa Recursos Geneticos e Biotecnologia
Ecological Research | Year: 2014

Natural tree regeneration in abandoned pastures can be hampered by various biotic and abiotic filters, including seed removal and predation. We tested the effects of maintenance and removal of grass and seed deposition (buried and unburied) on seed germination of 12 tree species in dry forest pastures. We obtained evidence supporting the hypothesis that seeds attain higher germination under a grass canopy than on bare ground. For most species, grass cover provides safety from seed predators and facilitates germination by providing a suitable microclimate with soil humidity similar to the forest. The hypothesis that buried seeds attain higher germination was not supported by our data. Predation and removal of unburied seeds ranged from 0 to 77 % and, alone or together, were the major causes of non-germination. Direct seeding is a promising technique for revegetation of recently abandoned pastures in areas originally covered by tropical dry forests. The high germination rate of seeds deposited on the ground and under grass reduces costs during initial restoration stages, potentially facilitating the spread and use of this technique. © 2014 The Ecological Society of Japan.

The objective of this work was to evaluate the agronomic performance of the maize and xaraés palisade grass (Urochloa brizantha 'Xaraés') crops in intercropping, grown in no-tillage and conventional tillage, in an agrosilvopastoral system, with the application of different nitrogen topdressing rates. The experiment was conducted in a maize crop area with the forest species "mulateiro" (Calycophyllum spruceanum). The experimental design was randomized complete blocks, in a split-plot arrangement with two systems of soil management (no-tillage and conventional tillage with heavy disk) allocated to the plots and five rates of nitrogen topdressing (0, 50, 100, 150, and 200 kg ha-1 N) to the subplots, totaling ten treatments. Maize grain yield responded linearly to N application in area of conventional tillage. In no-tillage area, the dose of 165 kg ha-1 N topdressing was necessary to obtain satisfactory yields. Nitrogen topdressing in maize crop until the dose of 200 kg ha-1 N does not influence xaraés palisade grass yield when intercropped between the lines, after maize harvest.

de Souza Gomes Guarino E.,Embrapa Acre | Scariot A.O.,Embrapa Genetic Resources and Biotechnology
Journal of Forest Research | Year: 2012

We evaluated the survival and growth of Amburana cearensis, Cedrela fissilis, and Sterculia striata seedlings in three seasonally tropical dry forest fragments that were subjected to different logging levels (intact, intermediately and heavily logged). In each fragment, we planted 40 seedlings of each species and monitored these over a period of 1 year. The highest seedling survival rate (64%) occurred in the heavily logged fragment, which, however, also had the highest mortality risk for all species during the dry season. Only S. striata seedlings had different survival rates among the fragments. Height and diameter growth were higher at sites with higher canopy openness in the wet season. The survival and growth rates of seedlings planted in logged fragments indicate that this technique can be applied to restore and enrich logged forests of the Paranã River Basin. © 2011 The Japanese Forest Society and Springer.

Strassburg B.B.N.,International Institute for Sustainability | Strassburg B.B.N.,Pontifical Catholic University of Rio de Janeiro | Latawiec A.E.,International Institute for Sustainability | Latawiec A.E.,Opole University of Technology | And 8 more authors.
Global Environmental Change | Year: 2014

Providing food and other products to a growing human population while safeguarding natural ecosystems and the provision of their services is a significant scientific, social and political challenge. With food demand likely to double over the next four decades, anthropization is already driving climate change and is the principal force behind species extinction, among other environmental impacts. The sustainable intensification of production on current agricultural lands has been suggested as a key solution to the competition for land between agriculture and natural ecosystems. However, few investigations have shown the extent to which these lands can meet projected demands while considering biophysical constraints. Here we investigate the improved use of existing agricultural lands and present insights into avoiding future competition for land. We focus on Brazil, a country projected to experience the largest increase in agricultural production over the next four decades and the richest nation in terrestrial carbon and biodiversity. Using various models and climatic datasets, we produced the first estimate of the carrying capacity of Brazil's 115 million hectares of cultivated pasturelands. We then investigated if the improved use of cultivated pasturelands would free enough land for the expansion of meat, crops, wood and biofuel, respecting biophysical constraints (i.e., terrain, climate) and including climate change impacts. We found that the current productivity of Brazilian cultivated pasturelands is 32-34% of its potential and that increasing productivity to 49-52% of the potential would suffice to meet demands for meat, crops, wood products and biofuels until at least 2040, without further conversion of natural ecosystems. As a result up to 14.3Gt CO2 Eq could be mitigated. The fact that the country poised to undergo the largest expansion of agricultural production over the coming decades can do so without further conversion of natural habitats provokes the question whether the same can be true in other regional contexts and, ultimately, at the global scale. © 2014 The Authors.

The objective of this work was to test the application of accuracy measures to determine the usefulness of nutritional diagnosis to compare different DRIS formulas, and to evaluate the use of these measures in the DRIS function modeling process. Three DRIS formulas were evaluated: bivariate relations (simplified); multivariate relations; and DRIS function modeling. Monitoring data from commercial mango orchards grown at São Francisco River Valley, Brazil, were used. Formula performances were evaluated based on the agreement of their diagnoses with the one provided by the sufficiency range method. Global accuracy, and the ones for insufficiency, equilibrium, excess, deficiency, sufficiency and nutritional toxicity were determined. The simplified and multivariate formulas showed similar results for insufficiency and deficiency accuracies, but they had a lower performance than the DRIS function modeling formula. This latter, for allowing of the adjustment of each DRIS function sensibility coefficient, showed to be promising in reducing the risks of false diagnosis for deficiency (as for not recommend the nutrient when it is necessary) and for insufficiency (as for recommend the nutrient when it is not necessary). However, the DRIS formula for function modeling does not show a satisfactory performance for other accuracy measures.

Wadt P.G.S.,Embrapa Acre | Dias J.R.M.,Federal University of Rondônia
Pesquisa Agropecuaria Brasileira | Year: 2012

The objective of this work was to evaluate the performance of regional and inter-regional norms of the diagnosis and recommendation integrated system (DRIS) on the nutritional diagnosis of Conilon coffee (Coffea canephora). Data on foliar contents of N, P, K, Ca, and Mg, obtained from 268 coffee crops from the states of Espírito Santo and Rondônia, Brazil, were used to define four sets of DRIS norms: three for specific conditions (regional norms), and one for all the tested conditions (inter-regional norms). Crops differed greatly as to management and environmental conditions. After the determination of the norms, the nutritional diagnoses obtained from them were confronted with each other. All the norms were effective in providing diagnoses to distinguish the nutritional patterns of the crops, both in the states of Espírito Santo and Rondônia. For the inter-regional DRIS norms, the means and standard deviations of the multivariate ratios between nutrients had intermediate values in comparison to those obtained for the sets of regional norms. No randomness was observed in the nutritional diagnosis provided by inter-regional norms, which had a great agreement level with the one provided by regional norms. Specific norms should be used only in the conditions in which they were developed, whereas generic norms have a wider applicability without jeopardizing the accuracy of the diagnosis.

Bergo C.L.,Embrapa Acre | Negreiros J.R.S.,Embrapa Acre | Miqueloni D.P.,Embrapa Acre | Lunz A.M.P.,Embrapa Acre
Revista Brasileira de Fruticultura | Year: 2013

Brazil is the largest producer and consumer of palm heart in the world. Its economic importance brings the need for studies to support the selection of superior individuals for breeding programs of species. Thus, the objective of this study was determinate the repeatability coefficient of the production characteristics of peach palm to palm heart in order to estimate the minimum number of evaluations capable of providing levels of certainty to the prediction of the progenies actual value. It was evaluated four cycles of cultivation of 85 half-sib progenies of peach palm race macrocarpa Putumayo. The experiment was conducted in randomized blocks and evaluated: base mass of the palm heart, mass of first and second quality of the palm heart, number of stalks per tiller, and diameter of the palm heart tillers per plot. Analysis of variance, principal components and structural determination of the repeatability coefficient and number of measurements were performed. There is regularity in predicting the superiority of individuals over the measurements for all traits. It takes seven cycles of measurements to predict the actual value of all traits of the progenies with 85% accuracy by the method of principal components based on the matrix of phenotypic variance and covariance.

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