Embrapa Amapa

Macapá, Brazil

Embrapa Amapa

Macapá, Brazil
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Yokomizo G.K.I.,Embrapa Amapa | Maia M.C.C.,Embrapa Agroindustria Tropical | da Trindade C.F.,Embrapa Amapa
Revista Caatinga | Year: 2017

Mangabeira fruits are collected from native populations under anthropic pressure. It is therefore essential to obtain morphogenetic information to genetically improve populations, thereby preventing genetic erosion. This research was carried out in the state Amapá and aimed to verify the morphological dissimilarity between two populations, one composed of 36 native progenies and one of eight progenies from Paraiba, outlined in lattices with two replications and six plants per part. The evaluated characteristics were: agronomic value (VA), treetop circumference (CCP), plant height (ALP), estimated number of fruits per plant (NEF), fruit color (COF), average weight of 10 fruits (PMF), fruit diameter (DF), average pulp weight of ten fruits (PMP), average length of 10 fruits (CMF), average number of seeds of 10 fruits (NMS). Our results indicate that the phenotype was mainly determined by responses to environmental changes; in the correlations, inherent fruit characteristics (weight, size, and color) did not affect the VA, while biometric characters influenced VA values. Higher plants presented larger fruits and a larger diameter, bigger quantities, there is also apparent contrast, with a larger amount of smaller size; the populations are dissimilar, indicating the possibility of obtaining of diverging superior segregating. © 2016, Universidade Federal Rural do Semi-Arid. All rights reserved.

Macedo Silva R.,University do Estado do Amapa | Tavares-Dias M.,Embrapa Amapa | Reis Dias M.W.,Embrapa Amapa | Reis Dias M.K.,Federal University of Amapá | das Gracas Barbosa Marinho R.,Federal University of Amapá
Pesquisa Agropecuaria Brasileira | Year: 2013

The objective of this work was to evaluate the parasitic fauna of hybrid tambacu (Colossoma macropomum x Piaractus mesopotamicus) from fish farms and the host-parasite relationship. A hundred and fourteen fish were collected from four fish farms in Macapá, in the state of Amapá, Brazil, 80.7% of which were infected by: Ichthyophthirius multifiliis (Ciliophora); Piscinoodinium pillulare (Dinoflagellida); Anacanthorus spatulatus, Notozothecium janauachensis, and Mymarothecium viatorum (Monogenoidea); Neoechinorhynchus buttnerae (Acanthocephala); Cucullanus colossomi (Nematoda); Perulernaea gamitanae (Lernaeidae); and Proteocephalidae larvae (Cestoda). A total of 8,136,252 parasites were collected from the examined fish. This is the first record of N. buttnerae, C. colossomi, N. janauachensis, M. viatorum, and Proteocephalidae for hybrid tambacu in Brazil. Ichthyophthirius multifiliis was the most prevalent parasite, whereas endohelminths were the less. A positive correlation was observed between number of I. multifiliis and total length and weight of fish, as well as between number of P. gamitanae and total length. The infection by I. multifiliis had association with the parasitism by Monogenoidea. Low water quality contributes to high parasitism of hybrid tambacu by ectoparasites, which, however, does not influence the relative condition factor of fish.

PubMed | Embrapa Amapa, National Institute of Amazonian Research, Embrapa Amazonia Ocidental, Federal University of Amapá and University do Oeste do Para
Type: | Journal: Veterinary parasitology | Year: 2017

In vivo and in vitro antiparasitic activity of the essential oil of Lippia sidoides and blood and histological alterations were assessed in Colossoma macropomum (tambaqui). Essential oil concentrations of 10, 20, 40, 80, 160 and 320mg/L were assayed in vitro against monogenoideans Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri from fish gills. Lippia sidoides essential oil concentrations of 320 and 160mg/L were 100% effective against monogenoideans in 10min and 1h of exposure, respectively. However, the effectiveness of 100% concentrations of 80mg/L and 40mg/L occurred in 3 and 6h, respectively. In the in vivo tests, juvenile fish were submitted to 60min of baths with 10mg/L and 15min of baths with 20mg/L of the essential oil of L. sidoides. These therapeutic baths were not efficient against Ichthyophthirius multifiliis, and monogenoideans present in the gills of C. macropomum. In addition, 10 and 20mg/L of the essential oil of L. sidoides caused an anesthetic effect on the fish and did not influence total glucose and protein plasma levels; however, it decreased the number of total erythrocytes in fish exposed to the higher concentration of this essential oil. Severe alterations and irreversible damage were observed in the fish gills just after L. sidoides essential oil baths and after 24h of recovery. The most recurrent lesions found were hyperplasia and fusion of the lamellar epithelium, vasodilation, detachment of the gill epithelium and lamellar aneurism, epithelial breakdown with hemorrhage, congestion, edema and necrosis, proliferation of the mucous cells and chloride cells and lamellar hypertrophy. Therefore, since the essential oil of L. sidoides has in vitro antiparasitic activity and low concentrations of it have shown toxic effects, the bioactive potential of its main chemical components should be investigated, as well as more efficient forms of its administration in therapeutic baths in order to eliminate fish parasites.

Lacerda A.C.F.,State University of Maringá | Takemoto R.M.,State University of Maringá | Tavares-Dias M.,Embrapa Amapa | Poulin R.,University of Otago | Pavanelli G.C.,State University of Maringá
Journal of Parasitology | Year: 2012

Biological invasions are considered a major threat to biodiversity around the world, but the role of parasites in this process is still little investigated. Here, we compared parasite infections of a host species in the areas where it originated and where it was introduced, and in native and introduced species in the same environment, using the endoparasites of the fish Plagioscion squamosissimus (Sciaenidae) in 3 Brazilian basins. Samples were taken in 2 rivers where the species is native, i.e., Solimes River (SO) and Tocantins River (TO), and where the species was introduced, the upper Paran River (PR). In addition, abundances of diplostomids and larval nematodes were compared between P. squamosissimus and 2 native competitors in the PR, Hoplias malabaricus and Raphiodon vulpinus. In total, 13 species of endoparasites were recorded, but only Austrodiplostomum sp. and cestode cysts were present in all localities. Although infracommunity richness was similar, their species composition was slightly different among localities. General linear models using the relative condition factor of fish as response variables, and abundance of the most prevalent parasites as possible predictors showed that the condition of fish is negatively correlated with parasite abundance only in the native range (TO). Abundance of diplostomid eye flukes was higher in the PR, and in the native species H. malabaricus when compared to the invader, which might present an advantage for P. squamosissimus if they compete for prey. However, although P. squamosissimus may have lost some of its native parasites during its introduction to the PR, it is now possibly acting as a host for native generalist parasites. © 2012 American Society of Parasitologists.

We determined the influence of resin ducts, sap content, and fruit physicochemical features of four mango cultivars (Criollo, Manila, Ataulfo, and Tommy Atkins) on their susceptibility to the attack of the two most pestiferous fruit fly species infesting mangoes in Mexico: Anastrepha ludens (Loew) and Anastrepha obliqua (Macquart). We performed three studies: 1) analysis of resin ducts in mango fruit exocarp to determine the density and area occupied by resin ducts in each mango cultivar, 2) assessment of mango physicochemical features including fruit sap content, and 3) a forced infestation trial under field conditions using enclosed fruit-bearing branches to expose mangoes to gravid A. ludens or A. obliqua females. Infestation rates, development time from egg to prepupae and pupae, pupal weight, and percent of adult emergence, were assessed. Ataulfo and Tommy Atkins cultivars exhibited the highest resin duct density and sap content, the lowest infestation rate, and had a negative effect on immature development and pupal weight. In sharp contrast, Manila and Criollo cultivars, with the lowest resin duct density and sap content, were highly susceptible to A. ludens and A. obliqua attack. We conclude that sap content and the number, size, and distribution of resin ducts as well as firmness in mango fruit exocarp are all involved in the resistance of mango to A. ludens and A. obliqua attack.

Castro G.S.A.,Embrapa Amapa | Crusciol C.A.C.,São Paulo State University
Geoderma | Year: 2013

Soil acidity and low natural fertility are the main problems for grain production in Brazilian 'cerrado'. Although lime has been the most applied source for soil correction, silicate may be an alternative material due to its lower solubility and Si supply, which is beneficial to several crops. This work aimed to evaluate the efficiency of superficial liming and calcium/magnesium silicate application on soil chemical attributes, plant nutrition, yield components and final yield of a soybean/white oat/maize/bean rotation under no-tillage system in a dry-winter region. The experiment was conducted under no tillage system in a deep acid clayey Rhodic Hapludox, Botucatu-SP, Brazil. The design was the completely randomized block with sixteen replications. Treatments consisted of two sources for soil acidity correction (dolomitic lime: ECC=90%, CaO=36% and MgO=12%; calcium/magnesium silicate: ECC=80%, CaO=34%, MgO=10% and SiO2=22%) applied in October 2006 to raise base saturation up to 70% and a control, with no soil correction. Soybean and white oat were sown in 2006/2007 as the main crop and off-season, respectively. Maize and bean were cropped in the next year (2007/2008). Products from silicate dissociation reach deeper soil layers after 18months from the application, compared to liming. Additionally, silicate is more efficient than lime to increasing phosphorus availability and reducing toxic aluminum. Such benefits in soil chemical attributes were only evidenced during bean cropping, when grain yield was higher after silicate application comparatively to liming. Both correction sources were improved mineral nutrition of all the other crops, mainly Ca and Mg levels and agronomical characteristics, reflecting in higher yield. © 2012 Elsevier B.V.

Although lime is currently the material most frequently used to ameliorate soil acidity in Brazil, silicate could efficiently replace this source because of its greater solubility and its greater silicon content, which are beneficial for plant development. This study aimed to evaluate the effects of superficial lime and silicate application on soil chemical attributes as well as on soybean and maize nutrition and grain yields when these crops are grown in rotation with green manure. The experimental design was a complete randomized block with sixteen replicates. Plots were treated with one of two materials for acidity correction (dolomitic lime and calcium/magnesium silicate) or with no soil correction, as a control. Silicate corrected soil acidity and increased exchangeable base levels in soil at greater depths faster than does liming. The application of both acidity-correcting materials increased N, Ca and Mg leaf concentrations, and all yield components and grain yield in soybean; but in maize, just silicate also increased N and Si when compared with lime, whereas both acidity-correcting increased just two yield components: grains per ear and mass of 100 grains, resulting in highest grain yield. The application of both acidity-correcting materials increased dry matter production of green manures, but for pigeon pea the silicate provided the best result in this dry-winter region. © 2015, Instituto Agronomico. All rights reserved.

Soratto R.P.,São Paulo State University | Crusciol C.A.C.,São Paulo State University | da Costa C.H.M.,São Paulo State University | Neto J.F.,São Paulo State University | Castro G.S.A.,Embrapa Amapa
Pesquisa Agropecuaria Brasileira | Year: 2012

The objective of this work was to evaluate the biomass production and the rates of decomposition and macronutrient and silicon release on crop residues of sunnhemp (Crotalaria juncea) and pearl millet (Pennisetum glaucum), in monocropped and intercropped systems. A randomized complete block design was used, with four replicates in a factorial arrangement consisting of three cover crops - pearl millet, sunnhemp, and these species intercropped - and six sampling times - 0, 18, 32, 46, 74, and 91 days after management (DAM). Pearl millet produces a greater amount of dry matter and accumulates more N, P, K, Mg, S, C, and Si, whereas sunnhemp accumulates more Ca. Pearl millet phytomass has the highest rates of decomposition and nutrient release. These rates are higher between 0 and 18 DAM. Over the time, the C/N, C/P and C/S ratios increase, and the C/Si ratio, as well as the decomposition rate, decreases. Potassium is the most rapidly released nutrient, and silicon has the lowest release rate.

Crusciol C.A.C.,São Paulo State University | Soratto R.P.,São Paulo State University | Castro G.S.A.,Embrapa Amapa | da Costa C.H.M.,São Paulo State University | Neto J.F.,São Paulo State University
Revista Ciencia Agronomica | Year: 2013

The application of silicon (Si) is beneficial to plants. However, there are doubts about the efficiency of foliar application. The objective of this work was to evaluate the effect of foliar application of Si, in the form of stabilized silicic acid (a newly developed source), on the nutrition and productivity of crops of soybean, common bean and peanut. The experimental design for each crop was of randomized blocks with fourteen replications. The treatments were foliar application of Si at a dosage of 2L ha-1 of Silamol ® (0.8% soluble Si as a stabilised concentrate of silicic acid) and a control (without the application of Si). The Si was divided into four applications. Foliar application increased the Si content, providing an increase in the number of pods and a higher seed yield in all three crops. The increase was around 14; 15 and 9.6%, respectively, for the soybean, common bean and peanut.

Castro G.S.A.,Embrapa Amapa | Crusciol C.A.C.,São Paulo State University
Pesquisa Agropecuaria Brasileira | Year: 2013

The objective of this work was to evaluate the efficiency of superficial applicationof limestone and slag, and their effects on soil chemical attributes and on yield and mineral nutrition of soybean, maize, and Congo signal grass (Urochloa ruziziensis). The experiment was carried out in a Rhodic Hapludox under no tillage system. The treatments consisted of the use of limestone or slag (silicates of calcium and magnesium) to correct soilacidity, and of a control treatment without the use of soil correctives. Rates were calculated in order to raise soil base saturation up to 70%. Soybean was sown in November 2006and maize in December 2007. Congo signal grass was sown right after the harvests of soybean and maize, and it was cropped during the offseasons. Soil chemical attributes were evaluated at 6, 12, and 18 months after the application of the corrective materials. Slag isan efficient source for soil acidity correction, being able to raise the exchangeable base levels in the soil profile faster than lime. Both limestone and slag increase dry matter yield of Congo signal grass, and grain yield of soybean and maize. Slag is more effective in improving maize grain yield.

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