Time filter

Source Type

Cruz W.P.,Federal University of Tocantins | Sarmento R.A.,Federal University of Tocantins | Teodoro A.V.,Embrapa Coastal Tablelands | Neto M.P.,Federal University of Tocantins | Ignacio M.,Federal University of Tocantins
Experimental and Applied Acarology | Year: 2013

Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies. © 2013 Springer Science+Business Media Dordrecht.

PubMed | Embrapa Coastal Tablelands and Federal University of Tocantins
Type: Journal Article | Journal: Experimental & applied acarology | Year: 2016

Weed management in physic nut plantations has generally been performed by spraying the herbicide glyphosate. However, the effects of glyphosate on non-target organisms present in the crop system are unknown. Here, we evaluated the toxicity of glyphosate (Roundup Transorb()) against the pest species Polyphagotarsonemus latus (Acari: Tarsonemidae) and Tetranychus bastosi (Acari: Tetranychidae) which can be exposed by drift. These mites are considered pests of the physic nut; however, they can also feed and reside on weeds associated with the crop, serving as food sources for predatory mites. When subjected to residue (by ingestion of sap of treated plants), and direct contact to glyphosate, P. latus reproduction was affected but T. bastosi was affected only by the residual effect. Although the herbicide caused a reduction in the number of eggs laid by the females of both pest mites, it is suggested that sublethal effects of glyphosate stimulates oviposition of P. latus and T. bastosi: both species displayed higher reproductive rates when exposed to 0.36kgha(-1) of the herbicide. We conclude that glyphosate negatively affects the arthropod herbivores studied and we discuss possible implications on their biological control in Jatropha curcas plantations.

Anthony F.,IRD Montpellier | Diniz L.E.C.,Embrapa Coastal Tablelands | Combes M.-C.,IRD Montpellier | Lashermes P.,IRD Montpellier
Plant Systematics and Evolution | Year: 2010

Phylogeographic analysis of the Coffea subgenus Coffea was performed using data on plastid DNA sequences and interpreted in relation to biogeographic data on African rain forest flora. Parsimony and Bayesian analyses of trnL-F, trnT-L and atpB-rbcL intergenic spacers from 24 African species revealed two main clades in the Coffea subgenus Coffea whose distribution overlaps in west equatorial Africa. Comparison of trnL-F sequences obtained from GenBank for 45 Coffea species from Cameroon, Madagascar, Grande Comore and the Mascarenes revealed low divergence between African and Madagascan species, suggesting a rapid and radial mode of speciation. A chronological history of the dispersal of the Coffea subgenus Coffea from its centre of origin in Lower Guinea is proposed. No relation was found between phylogenetic topology and the age of emergence of the volcanic islands that Coffea species have colonised in the Indian Ocean, suggesting dispersal from mainland Africa after the emergence of the youngest island, Grande Comore, 500,000 years ago. Additional sequences were obtained from GenBank for 24 species of other Rubiaceae genera, including the Rubia genus whose origin has been dated from the Upper Miocene. Estimates of substitution rates suggested that diversification in Coffea subgenus Coffea occurred about 460,000 years ago or as recently as the last 100,000 years, depending on the cpDNA region considered and calibration. The phylogenetic relationships based on plastid sequences confirmed biogeographic differentiation of coffee species, but they were not congruent with morphological and biochemical classifications, or with the capacity to grow in specific environments. Examples of convergent evolution in the main clades are given using characters of leaf size, caffeine content and reproductive mode. © The Author(s) 2010.

Fernandes M.F.,Embrapa Coastal Tablelands | Barreto A.C.,Embrapa Coastal Tablelands | Mendes I.C.,Embrapa Cerrados | Dick R.P.,Ohio State University
Agriculture, Ecosystems and Environment | Year: 2011

We evaluated the short-term (three years) impact of agricultural practices (soil tillage methods, maize cropping systems, and Brachiaria fallow) on the physical and chemical aspects of soil quality (SQ) of a kaolinitic Kandiudalfs in Northeastern Brazil, and the correlation between SQ and microbiological variables. A forest site was also sampled as reference of undisturbed soil. SQ was evaluated by multivariate analyses of total and particulate organic matter carbon, cation exchange capacity, mean weigh diameter and percentage of water stable aggregates of soil samples (0-20. cm depth). Phospholipid fatty-acids were used to quantify microbial biomass (MB), fungi to bacteria ratio (F/B) and an indicator of bacterial stress (19:0cy/18:1ω7c), whereas microbial enzyme activity was determined by the hydrolysis of fluorescein diacetate (FDA). A gradient of SQ, described by increases in the values of physical and chemical variables, was observed according to the sequence: cropped areas, irrespective to the agricultural practices < Brachiaria fallow < forest. SQ was positively correlated with MB, F/B and FDA, and negatively with 19:0cy/18:1ω7c. F/B was more sensitive than SQ to the agricultural practices. In the short term, the physical and chemical aspects of the quality of a kaolinitic soil is restored by Brachiaria fallow, but is not affected by tillage methods or maize. +. pigeonpea intercropping. F/B ratio is a potential predictor of changes in the quality of kaolinitic soils in response to agricultural practices. © 2011 Elsevier B.V.

PubMed | Embrapa Coastal Tablelands, Federal University of Sergipe and State University of Rio de Janeiro
Type: Journal Article | Journal: PloS one | Year: 2016

The diversity and genetic relationships among two accessions of tall coconut palms collected in Brazil and seven accessions introduced from different geographic regions of the world were analyzed using 25 microsatellite primers, 19 of which were polymorphic and detected between 4 and 10 alleles per locus, with an average of 6.57. The observed and expected heterozygosity ranged from 0.25 and 0.40 in the Rennell Islands Tall (RIT) accession to 0.54 and 0.62 in the Polynesian Tall (PYT) accession. The analysis of genetic structure resulted in the formation of five distinct groups. The first group was formed by the accessions Brazilian Tall-Praia do Forte (BRTPF), Brazilian Tall-Merepe (BRTMe) and West African Tall (WAT); the second group consisted of Malaysian Tall (MLT); the third group of RIT; the fourth group of Vanuatu Tall (VTT); and the fifth group of Rotuman Tall (RTMT), Tonga Tall (TONT) and PYT. The dendrogram based on the nearest-neighbor method detected the formation of two main groups and five subgroups, indicating that the genetic relationships of the accessions are based on their geographic regions of origin. The analyses revealed genetic relationships between the accessions collected in Brazil and the accession from Africa, and among palms from South East Asia and the South Pacific, confirming the common origin of these accessions. The information obtained in this study can guide decisions on germplasm conservation activities and the efficient selection of genetically divergent parents for use in coconut breeding programs in Brazil, which are attempting to select for disease resistance, mainly to lethal yellowing, among other characteristics.

Nogueira G.F.,Capes Embrapa Project | Pio L.A.S.,Federal University of Lavras | Pasqual M.,Federal University of Lavras | Amaral A.,Embrapa Coastal Tablelands | Scherwinski-Pereira J.E.,Embrapa Genetic Resources and Biotechnology
In Vitro Cellular and Developmental Biology - Plant | Year: 2014

In vitro conservation techniques can be utilized for germplasm maintenance. However, few reports on the in vitro conservation of sugarcane species are present in the literature. The objective of this study was to subject sugarcane plants to in vitro under minimal growth conditions and to evaluate the survival, regeneration, and the monitoring of nuclear DNA content levels of the plants. Shoots from 10 sugarcane varieties (Saccharum spp.) were introduced into two media: MC1, consisting of half-strength Murashige and Skoog (MS) salts and 3% sorbitol, or MC2, similar to the first formulation, but additionally supplemented with 3.8 μM abscisic acid (ABA). The shoots were maintained for up to 12 mo at 18°C in the presence of light. At the end of the period, the explants were inoculated onto multiplication medium containing 0.9 μM 6-benzylaminopurine (BAP) and 0.47 μM kinetin (Kin) for growth recovery. Flow cytometry analysis of shoots was verified at every 6 mo of storage. As a result, we found distinct behaviors of the varieties studied over the storage time, but in general, MC1 provided the greatest explant survival rates, with an average of approximately 80% cultures being able to recover. Once in the recovery media, the explant regrowth was fast, and the ability to multiply shoots was reestablished from the second 30-d subculture. However, by flow cytometry analysis, we observed a decrease in the estimated relative amount of DNA at 12 mo storage for most varieties examined, which was not observed when the monitoring was done at 6 mo. From these results, we conclude that sugarcane plants survived the minimal growth condition; however, maintaining the genotypes for extended periods in vitro may lead to variations in the estimated amount of nuclear DNA and, thus, be at risk of somaclonal variation. © 2014 The Society for In Vitro Biology

de Carvalho L.M.J.,Federal University of Rio de Janeiro | Gomes P.B.,Federal University of Rio de Janeiro | Godoy R.L.D.O.,Embrapa Food Technology | Pacheco S.,Embrapa Food Technology | And 6 more authors.
Food Research International | Year: 2012

Landrace pumpkins occur in nature and their potential as source of pro-vitamin A may be investigated in order to be used in conventional plant breeding or biofortification programs, aiming to increase the total carotenoids and β-carotene contents. The objective of the study was to determine the total carotenoid, α-carotene, β-carotene and its isomers and contents in two landrace samples (A and B) of raw pumpkins (Cucurbita moschata) to verify its seed production potential. High Performance Liquid Chromatography and UV/Visible spectrophotometry were used to determine α-carotene, β-carotene and its isomers, and total carotenoid contents, respectively. All analyses were carried out in triplicate. The results showed mean total carotenoid contents of 404.98 in sample A, and 234.21 μg/g in sample B. The α-carotene contents varied from 67.06 to 72.99 μg/g in samples A and B, respectively. All E-β-carotene was the most abundant isomer found varying from 244.22 to 141.95 μg/g in samples A and B, respectively. The 9 and 13-Z-β-carotene isomers were still found in low concentrations in both analyzed landrace samples. The content of β-carotene in raw sample A showed to be promising for the production of seeds for cultivation and consumption. © 2011 Elsevier Ltd.

Fernandes M.F.,Embrapa Coastal Tablelands | Saxena J.,Ohio State University | Dick R.P.,Ohio State University
Microbial Ecology | Year: 2013

The whole-cell lipid extraction to profile microbial communities on soils using fatty acid (FA) biomarkers is commonly done with the two extractants associated with the phospholipid fatty acid (PLFA) or Microbial IDentification Inc. (MIDI) methods. These extractants have very different chemistry and lipid separation procedures, but often shown a similar ability to discriminate soils from various management and vegetation systems. However, the mechanism and the chemistry of the exact suite of FAs extracted by these two methods are poorly understood. Therefore, the objective was to qualitatively and quantitatively compare the MIDI and PLFA microbial profiling methods for detecting microbial community shifts due to soil type or management. Twenty-nine soil samples were collected from a wide range of soil types across Oregon and extracted FAs by each method were analyzed by gas chromatography (GC) and GC-mass spectrometry. Unlike PLFA profiles, which were highly related to microbial FAs, the overall MIDI-FA profiles were highly related to the plant-derived FAs. Plant-associated compounds were quantitatively related to particulate organic matter (POM) and qualitatively related to the standing vegetation at sampling. These FAs were negatively correlated to respiration rate normalized to POM (RespPOM), which increased in systems under more intensive management. A strong negative correlation was found between MIDI-FA to PLFA ratios and total organic carbon (TOC). When the reagents used in MIDI procedure were tested for the limited recovery of MIDI-FAs from soil with high organic matter, the recovery of MIDI-FA microbial signatures sharply decreased with increasing ratios of soil to extractant. Hence, the MIDI method should be used with great caution for interpreting changes in FA profiles due to shifts in microbial communities. © 2013 Springer Science+Business Media New York.

Matos M.C.B.,State University of Maranhão | Silva S.S.,Embrapa Coastal Tablelands | Teodoro A.V.,State University of Maranhão
Revista Brasileira de Entomologia | Year: 2016

Solitary wasps and bees (Hymenoptera) play a key role in ecosystem and agroecosystem functioning. Crops may benefit from biological pest control and pollination carried out by predatory solitary wasps and solitary bees, respectively. Here, we aimed at evaluating the abundance and faunistic compositions of solitary wasps and bees in respect to land-use (pasture, alley cropping, young fallow and old fallow) over an entire year using trap nests in the Brazilian northeastern state of Maranhão. Land-use did not influence the abundance of solitary wasps and bees, however, levels of dominance, abundance and frequency of the species Pachodynerus guadulpensis Saussure, Isodontia sp. 1, Isodontia sp. 2, Trypoxylon nitidum Smith and Megachile cfr. framea Schrottky varied with land-use. The abundance of wasps and bees varied over the period of the year with populations peeking in January (bees), and June and July (wasps). Relative humidity explained most of the variation for the abundance of wasps while temperature explained higher portions of the variance for the abundance of bees. There was an interaction between period of the year and land-use for the abundance of wasps (but not for bees). We concluded that total population abundance of solitary wasps and bees were not affected by the land-use however, levels of dominance, abundance and frequency of some species of these hymenopterans changed according to land-use. Also, relative humidity and temperature were important environmental variables explaining the abundances of wasps and bees. © 2016 Sociedade Brasileira de Entomologia.

Chico D.,Technical University of Madrid | Santiago A.D.,Embrapa Coastal Tablelands | Garrido A.,Technical University of Madrid
Spanish Journal of Agricultural Research | Year: 2015

Ethanol production in Brazil has grown by 219% between 2001 and 2012, increasing the use of land and water resources. In the semi-arid north-eastern Brazil, irrigation is the main way for improving sugarcane production. This study aimed at quantifying water consumed in ethanol production from sugarcane in this region using the water footprint (WF) indicator and complementing it with an evaluation of the water apparent productivity (WAP). This way we were able to provide a measure of the crop´s physical and economic water productivity using, respectively, the WF and WAP concepts. We studied sugarcane cultivation under nine different water regimes, including rainfed and full irrigation. Data from a mill of the state of Alagoas for three production seasons were used. Irrigation influenced sugarcane yield increasing total profit per hectare and economic water productivity. Full irrigation showed the lowest WF, 1229 litres of water per litre of ethanol (L/L), whereas rainfed production showed the highest WF, 1646 L/L. However, the lower WF in full irrigation as compared to the rest of the water regimes implied the use of higher volumes of blue water per cultivated hectare. Lower water regimes yielded the lowest economic productivity, 0.72 US$/m3 for rainfed production as compared to 1.11 US$/m3 for full irrigation. Since economic revenues are increased with higher water regimes, there are incentives for the development of these higher water regimes. This will lead to higher general crop water and economic productivity at field level, as green water is replaced by blue water consumption. © 2015 INIA.

Loading Embrapa Coastal Tablelands collaborators
Loading Embrapa Coastal Tablelands collaborators