São Luís, Brazil
São Luís, Brazil

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Zonta J.B.,Embrapa Cocais | Araujo E.F.,Federal University of Viçosa | Araujo R.F.,EPAMIG CTZM | Dias L.A.S.,Federal University of Viçosa
Revista Brasileira de Sementes | Year: 2011

This study aimed to evaluate different types of drying and their effects on the physiological quality of physic nut seeds (Jatropha curcas L.). Seeds with 32% water content were dried in the shade to 9.9 %, in the sun to 8.8 %, in a forced circulation oven, at a temperature of 33 °C, to 8.5 % and at 43 °C to 8.3 % water content. The physiological seed quality was evaluated by germination, first count of germination, electrical conductivity and accelerated aging tests, as well as the seedling emergence index and emergence rate. A temperature of 43 °C dries seeds faster and lasts 42 hours. The drying period at 33 °C in the sun and shade lasted longer, at 54, 144 and 456 hours respectively. Shade drying caused an immediate reduction in physiological seed quality. Those seeds dried in the sun or at a temperature of 33 °C showed no differences regarding physiological status and were better than those dried in the shade. However, germination was lower than for seeds dried at 43 °C after 180 days storage. A drying temperature of 43 °C did not affect seed germination and only slightly reduced the vigor, even after 270 days storage. As the highest temperature used did not affect seed germination, it is suggested that seed drying time was crucial to its conservation. Physic nut seeds can be dried in the sun and in temperatures of 33 and 43 °C; a temperature of 43 °C results in a shorter drying time and a better germination and seed vigor of the physic nut whereas shade drying is detrimental to seed quality.


Silva G.F.,Laboratorio Of Biologia Molecular | Santos V.S.,Laboratorio Of Biologia Molecular | Sousa N.R.,Embrapa Cocais | Hanada R.E.,National Institute of Amazonian Research | Gasparotto L.,Laboratorio Of Fitopatologia
Genetics and Molecular Research | Year: 2016

Black sigatoka, caused by the fungus Mycosphaerella fijiensis (anamorphic stage: Paracercospora fijiensis), was first detected in Brazil in early 1998 in the Benjamin Constant and Tabatinga municipalities in the State of Amazonas, near to where the borders of Brazil, Colombia, and Peru converge. Understanding how cultivars react to the pathogen, and characterizing the genetic variability of isolates from two distant and distinct banana-producing regions, are important for determining the virulence of M. fijiensis. In the present study, the genetic diversity of 22 M. fijiensis isolates was assessed using simple sequence repeats (SSR) markers, and their virulence was determined following inoculation on three different banana tree cultivars. All 22 isolates caused symptoms of the disease in the Maçã and Prata Comum cultivars 45 days after inoculation, and at least two virulence groups were identified for the Maçã and Prata Comum cultivars. For the D’Angola cultivars, two virulence groups were observed only after 60 days post-inoculation, and three of the isolates were not virulent. Using SSR markers, the isolates from two different regions of Brazil were placed into two genetic groups, both genetically distant from the Mf 138 isolate collected in Leticia, Colombia. There was no evidence of correlation between the virulence groups and the genetic diversity groups. These results demonstrate variability in virulence between isolates as measured by the severity of black sigatoka in the analyzed cultivars. © FUNPEC-RP.


PubMed | National Institute of Amazonian Research, Laboratorio Of Biologia Molecular, Laboratorio Of Fitopatologia and Embrapa Cocais
Type: Journal Article | Journal: Genetics and molecular research : GMR | Year: 2016

Black sigatoka, caused by the fungus Mycosphaerella fijiensis (anamorphic stage: Paracercospora fijiensis), was first detected in Brazil in early 1998 in the Benjamin Constant and Tabatinga municipalities in the State of Amazonas, near to where the borders of Brazil, Colombia, and Peru converge. Understanding how cultivars react to the pathogen, and characterizing the genetic variability of isolates from two distant and distinct banana-producing regions, are important for determining the virulence of M. fijiensis. In the present study, the genetic diversity of 22 M. fijiensis isolates was assessed using simple sequence repeats (SSR) markers, and their virulence was determined following inoculation on three different banana tree cultivars. All 22 isolates caused symptoms of the disease in the Ma and Prata Comum cultivars 45 days after inoculation, and at least two virulence groups were identified for the Ma and Prata Comum cultivars. For the DAngola cultivars, two virulence groups were observed only after 60 days post-inoculation, and three of the isolates were not virulent. Using SSR markers, the isolates from two different regions of Brazil were placed into two genetic groups, both genetically distant from the Mf 138 isolate collected in Leticia, Colombia. There was no evidence of correlation between the virulence groups and the genetic diversity groups. These results demonstrate variability in virulence between isolates as measured by the severity of black sigatoka in the analyzed cultivars.


Signor D.,Embrapa Cocais | Signor D.,University of Sao Paulo | Cerri C.E.P.,University of Sao Paulo | Conant R.,Colorado State University | Conant R.,Queensland University of Technology
Environmental Research Letters | Year: 2013

Among the main greenhouse gases (CO2, CH4 and N 2O), N2O has the highest global warming potential. N 2O emission is mainly connected to agricultural activities, increasing as nitrogen concentrations increase in the soil with nitrogen fertilizer application. We evaluated N2O emissions due to application of increasing doses of ammonium nitrate and urea in two sugarcane fields in the mid-southern region of Brazil: Piracicaba (São Paulo state) and Goianésia (Goiás state). In Piracicaba, N2O emissions exponentially increased with increasing N doses and were similar for urea and ammonium nitrate up to a dose of 107.9 kg ha-1 of N. From there on, emissions exponentially increased for ammonium nitrate, whereas for urea they stabilized. In Goianésia, N2O emissions were lower, although the behavior was similar to that at the Piracicaba site. Ammonium nitrate emissions increased linearly with N dose and urea emissions were adjusted to a quadratic equation with a maximum amount of 113.9 kg N ha-1. This first effort to measure fertilizer induced emissions in Brazilian sugarcane production not only helps to elucidate the behavior of N2O emissions promoted by different N sources frequently used in Brazilian sugarcane fields but also can be useful for future Brazilian ethanol carbon footprint studies. © 2013 IOP Publishing Ltd.


Fernandes J.S.,Laboratorio Of Biologia Molecular | Angelo C.S.,Embrapa Cafe Fundacao Procafe | Cruz J.C.,Laboratorio Of Biologia Molecular | Santos J.M.M.,University of the State of Amazonas | And 2 more authors.
Genetics and Molecular Research | Year: 2016

Fusarium oxysporum f. sp cubense (Foc), the causal agent of Panama disease, is responsible for economic losses in banana crops worldwide. The identification of genes that effectively act on pathogenicity and/or virulence may contribute to the development of different strategies for disease control and the production of resistant plants. The objective of the current study was to analyze the importance of SGE1 gene expression in Foc virulence through post-transcriptional silencing using a double-stranded RNA hairpin. Thirteen transformants were selected based on different morphological characteristics, and sporulation in these transformants was significantly reduced by approximately 95% (P < 0.05) compared to that of the wild-type strain. The relative SGE1 expression levels in the transformant strains were reduced by 27 to 47% compared to those in the wild-type strain. A pathogenicity analysis revealed that the transformants were able to reach the rhizomes and pseudostems of the inoculated banana plants. However, the transformants induced initial disease symptoms in the banana plants approximately 10 days later than that by the wild-type Foc, and initial disease symptoms persisted even at 45 days after inoculation. These results indicate that the SGE1 gene is directly involved in the virulence of Foc. Therefore, SGE1 may be a potential candidate for host-induced gene silencing in banana plants. © FUNPEC-RP.


PubMed | Embrapa Cocais, Laboratorio Of Biologia Molecular, Embrapa Cafe Fundacao Procafe and University of the State of Amazonas
Type: Journal Article | Journal: Genetics and molecular research : GMR | Year: 2016

Fusarium oxysporum f. sp cubense (Foc), the causal agent of Panama disease, is responsible for economic losses in banana crops worldwide. The identification of genes that effectively act on pathogenicity and/or virulence may contribute to the development of different strategies for disease control and the production of resistant plants. The objective of the current study was to analyze the importance of SGE1 gene expression in Foc virulence through post-transcriptional silencing using a double-stranded RNA hairpin. Thirteen transformants were selected based on different morphological characteristics, and sporulation in these transformants was significantly reduced by approximately 95% (P < 0.05) compared to that of the wild-type strain. The relative SGE1 expression levels in the transformant strains were reduced by 27 to 47% compared to those in the wild-type strain. A pathogenicity analysis revealed that the transformants were able to reach the rhizomes and pseudostems of the inoculated banana plants. However, the transformants induced initial disease symptoms in the banana plants approximately 10 days later than that by the wild-type Foc, and initial disease symptoms persisted even at 45 days after inoculation. These results indicate that the SGE1 gene is directly involved in the virulence of Foc. Therefore, SGE1 may be a potential candidate for host-induced gene silencing in banana plants.


Brant R.S.,Embrapa Cocais | Pinto J.E.B.P.,Federal University of Lavras | Rosal L.F.,Instituto Federal Of Educacao | Alves C.,Federal University of Lavras | And 2 more authors.
Revista Brasileira de Plantas Medicinais | Year: 2011

The aim of this study was to evaluate physiological and anatomical modifications in lemon balm plants, cultivated under thermo-reflector nets (Aluminet ®) at different levels of shading, in order to understand the phenotypic plasticity in adaptation response to different light quantities. The treatments were characterized by plants subjected to full sun and 20 and 60% of luminous intensity, and arranged in completely randomized design (CRD). The quantifications of chlorophylls were done in four replicates, the measurements of epidermis and parenchymas were repeated 15 times and 10 replicates were used to evaluate characteristics of chloroplasts and their starch grains. Plants subjected to 20% of luminous intensity showed higher quantity of chlorophyll a and, therefore, higher chlorophyll a/b ratio. Lemon balm leaves under full sun and 60% of light showed thicker adaxial epidermis cells, but the abaxial epidermis cells showed characteristics found in shaded leaves, i.e., they were slender. The higher the light intensity, the larger the number of chloroplasts; however, under full sun, they were slender and had smaller area. The starch grains of leaves grown under shaded environments showed larger area and, at 60% of luminous intensity, occupied the largest part of chloroplasts. Thus, lemon balm plants, subjected to shading conditions, showed phenotypic plasticity.


Gualter R.M.R.,Federal Rural University of Rio de Janeiro | Boddey R.M.,Embrapa Agrobiologia | Rumjanek N.G.,Embrapa Agrobiologia | de Freitas A.C.R.,Embrapa Cocais | Xavier G.R.,Embrapa Agrobiologia
Pesquisa Agropecuaria Brasileira | Year: 2011

The objective of this work was to evaluate the agronomic efficiency of rhizobia strains for inoculation, in field conditions, of the cowpea BRS Guariba cultivar. Experiments were carried out in two areas in Santa Luzia do Paruá, Maranhão state, Brazil, in the Pre-Amazon region, in 2009. The BR 3299, BR 3262, INPA 03-11B Bradyrhizobium strains, an absolute control, and a nitrogen treatment (80 kg ha-1 N) were tested. At 30 and 50 days after emergence (DAE) of plants assesments were made. At 65 DAE, grain yield was evaluated. The number and dry weight of nodules, shoot dry mass, relative efficiency, and N accumulation in shoots were evaluated. All strains provided higher values for number and dry weight of nodules, and higher productivity in comparsion to the absolute control, without inoculation and urea, in the two areas. Regarding shoot dry matter, relative efficiency, and N accumulation in shoots, BR 3299 differed significantly from the absolute control, at 30 DAE, in one of the farms. Cowpea yield responds positively to inoculation with strains, especially strain BR 3299.


do Nascimento E.N.,University Vale do Acarau | Rogerio M.C.P.,Embrapa Caprinos e Ovinos | Batista A.S.M.,University Vale do Acarau | Carneiro M.S.S.,Federal University of Ceará | And 6 more authors.
Revista Brasileira de Saude e Producao Animal | Year: 2012

This work aimed to determine the nutrient intake and quantitative aspects of sheep carcass from three different genetic groups. Eighteen animals with initial average body weight of 20.1kg were used in a completely randomized design, in a factorial 3x2 scheme (three different crossbreeds - 6 F1Dorper x non defined breed, 6 F1Somalis x non defined breed and 6 F1Santa Inês x non defined breed versus two diets). The diets fed to the animals were formulated with or without cashew nuts. The inclusion of cashew nut meal in the diet influenced nutrient intake. Differences of intake among the animal groups were observed as higher intake for F1Dorper x non defined breed (NDB), followed by F1Somalis x NDB and for F1Santa Inês x NDB. However, the control diet produced no difference among these genotypes. The average daily gain was lower for both crossbreeds when cashew nut meal was added in the diets. The evaluated crossbreeds and diets did not affect the feed:gain ratio. The carcasses analyses showed that the inclusion of cashew nut meal in the diets reduced the cold carcass weight and the rib weight. The addition of cashew nut meal in the diets for lambs reduces food intake and carcass yield. The crossbreed F1Dorper x NDB presented the higher rate of average daily gain.


PubMed | Embrapa Cocais, DuPont Company, Federal University of Lavras and Embrapa Semi Arido
Type: | Journal: TheScientificWorldJournal | Year: 2014

This study was carried out to obtain the estimates of genetic variance and covariance components related to intra- and interpopulation in the original populations (C0) and in the third cycle (C3) of reciprocal recurrent selection (RRS) which allows breeders to define the best breeding strategy. For that purpose, the half-sib progenies of intrapopulation (P11 and P22) and interpopulation (P12 and P21) from populations 1 and 2 derived from single-cross hybrids in the 0 and 3 cycles of the reciprocal recurrent selection program were used. The intra- and interpopulation progenies were evaluated in a 10 10 triple lattice design in two separate locations. The data for unhusked ear weight (ear weight without husk) and plant height were collected. All genetic variance and covariance components were estimated from the expected mean squares. The breakdown of additive variance into intrapopulation and interpopulation additive deviations ( (2)) and the covariance between these and their intrapopulation additive effects (Cov A) found predominance of the dominance effect for unhusked ear weight. Plant height for these components shows that the intrapopulation additive effect explains most of the variation. Estimates for intrapopulation and interpopulation additive genetic variances confirm that populations derived from single-cross hybrids have potential for recurrent selection programs.

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