Lima N.B.,University of Pernambuco |
De A. Batista M.V.,Federal University of Pernambuco |
De Morais Jr. M.A.,Federal University of Pernambuco |
Barbosa M.A.G.,Embrapa Semiarido |
And 3 more authors.
Fungal Diversity | Year: 2013
Colletotrichum species are the most important and widespread form of decay affecting mango fruit worldwide. In this study, Colletotrichum species associated with fruit anthracnose isolated from mango in northeastern Brazil were subject to molecular and morphological analyses. The partial sequences of the glyceraldehyde-3-phosphate dehydrogenase gene of 143 Colletotrichum isolates was amplified, as an initial measure of genetic diversity. A subset of 47 isolates, selected to represent the range of genetic diversity and geographic origin, were further sequenced using the partial actin, β-tubulin, calmodulin, glutamine synthetase genes and rDNA-ITS region. The multilocus sequence analysis, together with a critical examination of the phenotypic characters, revealed four previously described species (Colletotrichum asianum, Colletotrichum fructicola, Colletotrichum tropicale and Colletotrichum karstii) and one new species. The new species is introduced as Colletotrichum dianesei and formally described, illustrated and compared with similar taxa. Only C. asianum and C. karstii have previously been reported from mango, while the other species represent the first report associated with the mango fruits worldwide. All species are reported for the first time associated with the mango fruits in Brazil. © 2013 Mushroom Research Foundation.
de Teixeira A.H.C.,Embrapa Semiarido |
Bastiaanssen W.G.M.,WaterWatch |
Bastiaanssen W.G.M.,Technical University of Delft
Irrigation Science | Year: 2012
Energy balance measurements were carried out in a mango orchard during two growing seasons in the semi-arid region of Brazil. The actual evapotranspiration (ET) was acquired by eddy correlation (EC) and Bowen ratio energy balance (BR) techniques. The daily energy balance closure in the EC measurements showed an average gap of 12%, with a root mean square error (RMSE) of 1.7 MJ m-2 d-1. Three different correction procedures were tested for closing the energy balance from the EC system: (1) the surface energy balance residual method (RES), (2) the Bowen ratio determined from the EC fluxes, the combination approach (EC_BR), and (3) a new regression energy balance closure technique (REG). All closing energy balance methods presented good correlation with the direct EC measurements, but the trends were not similar. The latent heat fluxes estimated by the BR method-λEBR-were higher than those from the direct EC measurements-λEEC. When using the RES method, the half-hour λEEC measurements represented around 88% of the λERES values, as the uncertainties of net radiation-Rn-and soil heat fluxes-G-are propagated into the RES method. The latent heat flux derived from the combination approach-λEEC_BR-also brings these uncertainties, being the agreements comparable with those for RES method. It was therefore concluded that a single correction method for EC measurements considering only the latent and sensible heat fluxes does not exist. A new way to solve the lack of energy balance closure from EC techniques was tested by means of a curve fitting, the REG method. Considering the REG corrections applied to the energy balance components involving all periods of the day and the average conditions of the two growing seasons, half-hour values of λEEC were overmeasured by 18%, HEC was undermeasured by 17%, and G values required a correction of 466%. The REG method appeared promising because it considers different weights for all energy balance components in the optimization process. Taking the REG results for the drier second growing season as a reference, it was concluded that seasonal ET values by the other methods in mango orchard ranged from 7 to 28% higher, showing that turbulent flux measurements lack accuracy for executing on-farm water-saving programmes and calibrating transient soil water flow models. © 2010 Springer-Verlag.
Santos C.A.F.,Embrapa Semiarido |
de Souza Gama R.N.C.,State University of Feira de Santana
Revista de Biologia Tropical | Year: 2013
The umbu tree (Spondias tuberosa) is one of the most important endemic species to the Brazilian tropical semiarid region. The umbu tree has edible fruits with a peculiar flavor that are consumed in natura or in a semi-industrialized form, such as jams, candies and juices. The majority of endemic species to Brazilian semiarid region have not been studied or sampled to form germplasm collections, which increases the risk of losing genetic variability of the adapted species to xerophytic conditions. The aim of this study was to estimate outcrossing rates in S. tuberosa using a multilocus mixed model in order to guide genetic resources and breeding programs of this species. DNA samples were extracted from 92 progenies of umbu trees, which were distributed among 12 families. These trees were planted by seed in 1991 in Petrolina, PE, Brazil. The experimental design was a randomized block, with a total of 42 progenies sampled in three regions. The experimental units were composed by five plants and five replications. The outcrossing rate was estimated by the multilocus model, which is available in the MLTR software, and was based on 17 polymorphic AFLP bands obtained from AAA_CTG and AAA_CTC primer combinations. The observed heterozygotes ranged from 0.147 to 0.499, with a maximum frequency estimated for the AAA_CTC_10 amplicon. The multilocus outcrossing estimation (tm) was 0.804±0.072, while the single-locus (ts) was 0.841±0.079, which suggests that S. tuberosa is predominantly an outcrossing species. The difference between tm and ts was -0.037±0.029, which indicates that biparental inbreeding was nearly absent. The mean inbreeding coefficient or fixation index (F) among maternal plants was - 0.103±0.045, and the expected F was 0.108, which indicates that there was no excess of heterozygotes in the maternal population. The outcrossing estimates obtained in the present study indicate that S. tuberosa is an open-pollinated species. Biometrical models applied to this species should therefore take into account the deviation from random outcrossing to estimate genetic parameters and the constitution of broad germplasm samples to preserve the genetic variability of the species. Outcrossing rates based on AFLP and the mixed-mating model should be applied to other studies of plant species in the Brazilian semiarid region.
de Freitas S.T.,Embrapa Semiarido |
Mitcham E.J.,University of California at Davis
Scientia Agricola | Year: 2013
Pitaya (Hylocereus undatus) is an exotic non-climacteric fruit that reaches its best eating quality when harvested ripe, decreasing thereafter during storage. Our objectives were to determine the best combination of storage temperature and use of perforated plastic bags to maintain the postharvest quality of the fruit. Fruits were stored at 5, 7, or 10 °C with and without a perforated plastic bag for 20 days, followed by five days at 20 °C without the bag for shelf-life determination. Storage at 5 °C, followed by 7 °C maintained better visual appearance of the pitaya fruit after 20 days, by reducing decay incidence and severity, and maintaining greener bracts compared with fruit stored at 10 °C. Pitaya fruit stored at 5 °C without a perforated plastic bag showed no decay after storage and shelf-life. In general, higher temperatures and the use of a perforated plastic bag increased decay incidence, as well as decay severity after storage and shelf-life conditions. At all temperatures, fruit stored in a perforated plastic bag had lower weight loss during storage. After shelf-life, weight loss was highest in fruit stored at higher temperatures. Storage of fruits at 5 °C resulted in minor chilling injury symptoms in the outer flesh tissue, close to the peel. Storage at 5 °C without a perforated plastic bag was the best condition to maintain the postharvest quality of the pitaya fruit.
Leao P.C.S.,Embrapa Semiarido |
Motoike S.Y.,Federal University of Viçosa
Pesquisa Agropecuaria Brasileira | Year: 2011
The objective of this work was to analyze the genetic diversity of 47 table grape accessions, from the grapevine germplasm bank of Embrapa Semiárido, using 20 RAPD and seven microsatellite markers. Genetic distances between pairs of accessions were obtained based on Jaccard's similarity index for RAPD data and on the arithmetic complement of the weighted index for microsatellite data. The groups were formed according to the Tocher's cluster analysis and to the unweighted pair-group method with arithmetic mean (UPGMA). The microsatellite markers were more efficient than the RAPD ones in the identification of genetic relationships. Information on the genetic distance, based on molecular characteristics and coupled with the cultivar agronomic performance, allowed for the recommendation of parents for crossings, in order to obtain superior hybrids in segregating populations for the table grape breeding program of Embrapa Semiárido.
Santos C.A.F.,Embrapa Semiarido |
Da Costa D.C.C.,Embrapa Semiarido |
Da Silva W.R.,Embrapa Semiarido |
Boiteux L.S.,Embrapa Hortalicas
Crop Science | Year: 2012
Genetic parameters, heritability, and minimum number of genes for total seed protein content were estimated in tropical semiaridadapted cowpea [Vigna unguiculata (L.) Walp.] germplasm aiming to provide the basis for the development of cultivars with higher nutritional value. Generation mean and variance analyses were conducted with the parental lines, F1, F2, and backcross populations derived from two contrasting crosses 'IT97K-1042-3' (31.15% total seed protein content) × 'BRS Tapaihum' (24.35%) and IT97K-1042-3 × 'Canapu' (22%). Narrowsense heritabilities were moderate (47.7%) in the cross IT97K-1042-3 × BRS Tapaihum and high (87.6%) in the cross IT97K-1042-3 × Canapu. The analyses indicated (in both crosses) the importance of additive gene effects and the parental mean for total seed protein. The minimum gene number, estimated by different methods, ranged from three to seven in the IT97K-1042-3 × Canapu cross and three to less than 25 in the IT97K-1042-3 × BRS Tapaihum cross. Transgressive segregation was observed in the F2 population from the cross IT97K-1042-3 × Canapu, with individual plants displaying up to 34.1% seed protein content. The results suggest that, although under polygenic control, the seed protein content in cowpea can be improved via standard breeding methods largely used in selfpollinated crops. © Crop Science Society of America.
Santos C.A.F.,Embrapa Semiarido |
Boiteux L.S.,Embrapa Hortalicas
Genetics and Molecular Research | Year: 2013
One strategy to mitigate human malnutrition in semi-arid areas is to increase the protein and mineral content of cowpea cultivars. Total seed protein, potassium, calcium, iron, zinc, and sodium contents were quantifed in elite cowpea lines, with the aim to develop cultivars that had improved levels of these nutrients. Eighty-seven F6 lines derived from 6 crosses were evaluated under rain-fed conditions in Petrolina, Brazil. Seed protein and mineral content were quantifed by the micro-Kjeldhal method and in an atomic absorption spectrophotometer, respectively. Statistical analyses were estimated for all traits, including grain yield. Signifcant differences were observed for all characteristics. Seed protein content ranged from 22.5 to 34.1%, potassium levels ranged from 20,200 to 27,000 ppm, and calcium levels ranged from 410 to 6260 ppm. Iron content ranged from 36.5 to 137 ppm, while zinc content ranged from 36 to 58 ppm and sodium content ranged from 29.2 to 88 ppm. Simple correlation coeffcient values indicated that selection for high protein and mineral content does not affect grain yield. These results demonstrate that it is feasible to obtain new biofortifed cowpea cultivars by combining higher levels of protein and essential minerals. © FUNPEC-RP.
Wadt P.G.S.,Embrapa Acre |
Silva D.J.,Embrapa Semiarido
Pesquisa Agropecuaria Brasileira | Year: 2010
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.
de C. Teixeira A.H.,Embrapa Semiarido
Remote Sensing | Year: 2010
To achieve sustainable development and to ensure water availability inhydrological basins, water managers need tools to determine the actual evapotranspiration (ET) on a large scale. Field energy balances from irrigated and natural ecosystems togetherwith a net of agro-meteorological stations were used to develop two models for ETquantification at basin scale, based on the Penman-Monteith equation. The first model (PM1) uses the resistances to the latent heat fluxes estimated from satellite measurements,while the second one (PM2) is based on the ratio of ET to the reference evapotranspiration (ET0) and its relation to remote sensing parameters. The models were applied in the Low-Middle São Francisco river basin in Brazil and, after comparison against field results, showed good agreements with PM1 and PM2 explaining, respectively, 79% and 89% of the variances and mean square errors (RMSE) of 0.44 and 0.34 mm d-1. Even though the PM1 model was not chosen for ET calculations, the equation for surface resistance (rs) was applied to infer the soil moisture conditions in a simplified vegetation classification. The maximum values of rs were for natural vegetation-caatinga (average of 1,937 s m-1).Wine grape and mango orchard presented similar values around 130 s m-1, while table grape presented the lowest ones, averaging 74 s m-1. Petrolina and Juazeiro, in Pernambuco (PE) and Bahia (BA) states, respectively, were highlighted with the biggest irrigated areas. The highest increments are for vineyards and mango orchards. For the first crop the maximum increment was verified between 2003 and 2004 in Petrolina-PE, when the cultivated area increased 151%. In the case of mango orchards the most significant period was from 2005 to 2006 in Juazeiro-BA (129%). As the best performance was for PM2, it was selected and used to analyse the regional ET at daily and annual scales, making use of Landsat images and a geographic information system for different soil moisture conditions. Considering the daily rates of the regional ET, pixels with values lower than 1.0 mm d-1 occurred outside the rainy season, representing the caatinga species. Values from 1.0 to 5.0 mm d-1 during the driest conditions of the year coincided with irrigated crops, being the highest values for table grapes. The highest accumulated ET values during 2006 were for mango orchards, being around 500-1,300 mm yr-1. Vineyards presented lower values, ranging from 450-800 mm yr-1, while in caatinga they werebetween 200 and 400 mm yr-1. It could be concluded that irrigated mango orchards andvineyards in that year consumed more water than caatinga by factors of 3 and 2, respectively. The mango orchards and vineyard areas, representing 19.4 and 8.2% of the total irrigated area, respectively, resulting in a total evaporative depletion of 0.22 km3 yr-1 in the growing regions comprised of the agro-meteorological stations. © 2010 by the authors; licensee MDPI, Basel, Switzerland.
Bassoi L.H.,Embrapa Semiarido |
Goncalves S.O.,São Paulo State University
IRRIGA | Year: 2011
Irrigation management may influence the ecophysiological behavior and yield of grapevine. The objective of this study was to evaluate the influence of different irrigation management strategies in leaf water potential, quantitative and qualitative aspects of grapes from the first growing season of cv. Syrah / Paulsen 1103 vineyard. The experiment was carried out at experimental field of Embrapa Tropical Semiarid, in Petrolina, Pernambuco State, Brazil. Plants were irrigated by drippers and irrigation depth was estimated based on crop evapotranspiration. The experimental design was a randomized block, with 4 replications, and with 3 treatments: full irrigation with water application throughout the growing season; deficit irrigation with water application interrupted in the pea-sized berries phase; and regulated deficit irrigation with irrigation also interrupted in the same phenological phase but eventually performed after that according to soil water monitoring. Plant water deficit has favored a higher sugar concentration and lower acidity in the berries which are desirable for winemaking.