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Search Results: 1 - 10 of 480100 matches for " MARTINELLI Luiz A. "
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Resistência quantitativa à ferrugem da folha em genótipos de aveia branca: II - Avalia??o de componentes de resistência
Chaves, Márcia S;Martinelli, José A;Federizzi, Luiz C;
Fitopatologia Brasileira , 2004, DOI: 10.1590/S0100-41582004000100008
Abstract: the use of quantitative resistance as a form to control oat (avena sativa) crown rust can be a viable alternative, once there is differentiated reaction among oat genotypes in field, which shows great variation. the slow disease progress observed in the field is the result of combined effects of resistance components as low infection efficiency, longer latent period, low number of spores per pustule and little pustules size. this work was accomplished in 1999 and 2000, and its objective was to quantify the resistance components above mentioned in 31 white oat genotypes. the reaction of these genotypes was evaluated in the field, from 1996 to 2000, and they were classified in four groups. evaluation of resistance components was accomplished in seedlings and adult plants maintained in controlled conditions, and the last two components were also quantified in leaves collected in the field trials. genotypes showed variability for all measured characteristics, except for latent period in seedlings, and those genotypes classified as resistant in the field presented the best combination of desirable components.
Resistência quantitativa à ferrugem da folha em genótipos de aveia branca: I - Caracteriza??o da rea??o em condi??es de campo
Chaves, Márcia S;Martinelli, José A;Federizzi, Luiz C;
Fitopatologia Brasileira , 2004, DOI: 10.1590/S0100-41582004000100007
Abstract: among diseases that attack oat (avena sativa) crop, crown rust, caused by puccinia coronata f. sp. avenae, has been the most destructive, being responsible for a decrease in the quality and yield of grains. control through qualitative resistance has been restricted by the capacity of the pathogen to overcome this resistance type. seeking an alternative strategy for disease control, 31 white oat genotypes were investigated for the occurrence of quantitative resistance. trials were accomplished from 1996 to 2000, in the agronomic experimental station of ufrgs, in eldorado do sul, rs, brazil. disease progress was evaluated in the field for three years, and some genotypes were tested for five years. weekly evaluations of rust severity in each plot were performed, providing data from which to determine the disease progress curves, and calculate the area under the disease progress curve (audpc), and the rate of development of disease (r). there was great variability among genotypes for all the years in regard to rust reaction, allowing the genotypes to be classified in four groups: resistant, moderately resistant, moderately susceptible and susceptible. the first two groups have good levels of quantitative resistance and can be used in the future as parents in breeding programs.
Resistência quantitativa à ferrugem da folha em genótipos de aveia branca: III - Correla??o de componentes de resistência entre si e com a intensidade de doen?a no campo
Chaves, Márcia S.;Martinelli, José A.;Federizzi, Luiz C.;
Fitopatologia Brasileira , 2004, DOI: 10.1590/S0100-41582004000200013
Abstract: selection of genotypes for quantitative resistance to oat crown rust, based on its components, needs the knowledge of the association of these components with each other and with the amount of disease in the field, represented by audpc. this work aimed to determine these correlations, based on results of previous trials, in which the reaction of 31 white oat genotypes was tested and the resistance components were quantified. correlations were usually low for the resistance components with each other and for these components with the amount of disease in the field. higher correlations, consistent among years, with audpc were infection frequency in seedlings and latent period and pustule size in adult plants. all other possible correlations were very low. these data suggest that the resistance components mentioned can influence the expression of quantitative resistance in the field in a somewhat important manner. nevertheless, the low correlation of resistance components with each other indicates that genotype selection, in this host-pathogen interaction, must not be based on a single resistance component assessment. the correlation analysis suggests that the expression of quantitative resistance to oat crown rust is not conditioned by a single resistance component but by the group effect of all of them. in addition, it is possible that different mechanisms are involved for each genotype, in such a way that the more important resistance component in one genotype may not be the same for another.
Resistência quantitativa à ferrugem da folha em genótipos de aveia branca: II - Avalia o de componentes de resistência
Chaves Márcia S,Martinelli José A,Federizzi Luiz C
Fitopatologia Brasileira , 2004,
Abstract: A utiliza o da resistência quantitativa como forma de controle da ferrugem da folha da aveia (Avena sativa) pode ser uma alternativa viável, visto que há rea o diferenciada entre genótipos em condi es de campo, a qual apresenta grande espectro de varia o. O progresso lento da moléstia observado a campo é o resultado dos efeitos combinados de componentes de resistência como baixa eficiência de infec o, período de latência longo, baixa produ o de esporos por pústula e pequeno tamanho de pústulas. Este trabalho foi realizado durante os anos de 1999 e 2000, e teve por objetivo quantificar os componentes de resistência acima citados em 31 genótipos de aveia branca. A rea o destes genótipos foi avaliada a campo, durante os anos de 1996 a 2000, os quais foram classificados em quatro grupos. A avalia o dos componentes de resistência foi realizada em plantulas e plantas adultas mantidas em condi es controladas, sendo que os dois últimos componentes também foram quantificados em folhas coletadas nos ensaios de campo. Os genótipos apresentaram variabilidade para todas as características avaliadas, exceto para o período de latência em plantulas, sendo que aqueles classificados como resistentes no campo apresentaram a melhor combina o de componentes desejáveis.
Resistência quantitativa à ferrugem da folha em genótipos de aveia branca: I - Caracteriza o da rea o em condi es de campo
Chaves Márcia S,Martinelli José A,Federizzi Luiz C
Fitopatologia Brasileira , 2004,
Abstract: Entre as doen as que se manifestam na cultura da aveia (Avena sativa), a ferrugem da folha, causada por Puccinia coronata f. sp. avenae, tem-se mostrado a mais destrutiva, sendo responsável pelo decréscimo na qualidade e no rendimento dos gr os. O controle da doen a através do uso de cultivares com resistência qualitativa vem sendo restringido pela capacidade do patógeno em superar este tipo de resistência. Visando possibilitar a utiliza o de uma estratégia alternativa para o controle da doen a, foi investigada a ocorrência de resistência quantitativa em 31 genótipos de aveia branca. Os ensaios foram realizados durante os anos de 1996 a 2000, na Esta o Experimental Agron mica da UFRGS, em Eldorado do Sul, RS, Brasil. Foi avaliado o progresso da doen a no campo nos genótipos durante três anos, sendo que alguns deles foram testados durante cinco anos. Para tal, foram realizadas avalia es semanais da severidade da ferrugem nas parcelas, tra ando-se, a partir destes dados, as curvas de progresso da doen a, sendo calculadas também as áreas delimitadas por essas curvas (AACPD) e a taxa de progresso da doen a (r). Em todos os anos houve grande variabilidade entre os genótipos quanto à rea o à ferrugem da folha, e, conforme sua rea o ao longo dos anos em que foram testados, os genótipos foram classificados em quatro grupos: resistentes, moderadamente resistentes, moderadamente suscetíveis e suscetíveis. Os dois primeiros grupos apresentam bons níveis de resistência quantitativa e poder o ser usados futuramente como genitores em programas de melhoramento genético.
Resistência quantitativa à ferrugem da folha em genótipos de aveia branca: III - Correla o de componentes de resistência entre si e com a intensidade de doen a no campo
Chaves Márcia S.,Martinelli José A.,Federizzi Luiz C.
Fitopatologia Brasileira , 2004,
Abstract: A sele o de genótipos com resistência quantitativa à ferrugem da folha da aveia (Avena sativa), baseada nos componentes que a condicionam, necessita do conhecimento da associa o destes componentes entre si e deles com a quantidade de doen a no campo, representada pela área abaixo da curva de progresso da doen a (AACPD). Este trabalho objetivou determinar estas correla es, a partir de resultados de ensaios realizados previamente, em que 31 genótipos de aveia branca tiveram sua rea o à ferrugem determinada no campo e seus componentes de resistência quantificados. As correla es encontradas foram geralmente baixas, tanto dos componentes entre si, como deles com a intensidade da doen a no campo. As correla es mais altas, e consistentes entre os anos, com a AACPD foram da eficiência de infec o em plantulas, do período de latência e do comprimento de pústulas em plantas adultas. Estes dados sugerem que os componentes citados podem ter uma influência um pouco maior que os demais sobre a express o da resistência parcial a campo. Entretanto, a baixa correla o entre os componentes medidos, indica que a sele o de genótipos, nesta intera o patógeno-hospedeiro, n o deve ser realizada com base em apenas um componente de resistência. Os resultados sugerem que a express o da resistência parcial à ferrugem da folha da aveia n o é condicionada apenas por um componente de resistência, mas sim pelo efeito conjunto de todos eles. Além disto, é possível que mecanismos diferenciados estejam atuando em cada genótipo, de forma que os componentes de resistência mais importantes para um n o sejam os mesmos para outro.
Water Use in Sugar and Ethanol Industry in the State of São Paulo (Southeast Brazil)  [PDF]
Luiz A. Martinelli, Solange Filoso, Cecilia de Barros Aranha, Silvio F. B. Ferraz, Tatiana M. B. Andrade, Elizabethe de C. Ravagnani, Luciana Della Coletta, Plinio Barbosa de Camargo
Journal of Sustainable Bioenergy Systems (JSBS) , 2013, DOI: 10.4236/jsbs.2013.32019
Abstract:

Brazil is the largest producer of ethanol from sugarcane in the world. While the ethanol industry is economically important to Brazil for several reasons, it also has a significant impact on the environment. Here we analyze the water consumptive use in the transformation of the feedstock (sugarcane) into ethanol and the impact of industrial byproduct effluents on water resources of the state of Sao Paulo, Brazil. Our estimates indicated that in the 2007-2008 harvest, 700 million m3 was withdrawn mainly from rivers and streams by 140 mills, and of this total 440 million m3 was consumed which yielded a water use of approximately 1.53 m3 ·water·tonˉ1 sugarcane or approximately 18 L·water·L-ˉ1 ethanol. At the same time, a total of 120 million m3 of vinasse by-product was produced in the state, equivalent to an organic load of approximately 3 billion kg·BOD during the harvest season or approximately 8 million kg·BOD·dˉ1. Although the water used by sugarcane mills has decreased in recent decades, it is still possible to further decrease the amount of water used by ethanol production. This would decrease the pressure on 1st order streams of the state from which most water is withdrawn. In addition, the enormous volume of vinasse production must be reduced because it exerts constant pressure on aquatic ecosystems, soil and groundwater due to the constant increase in the potassium (K) concentration in areas where it is used as a fertilizer.

Processo de infec??o e forma??o de mancha em gr?os de aveia branca com níveis diferenciados de resistência para Pyrenophora chaetomioides
Bocchese, Carla A. C.;Martinelli, José A.;Federizzi, Luiz C.;Rosa, Carlos R. E.;
Fitopatologia Brasileira , 2006, DOI: 10.1590/S0100-41582006000300007
Abstract: the black spots of oat (avena sativa) grains, caused mainly by pyrenophora chaetomioides, is characterized by the darkening of their superficial tissues, with reduction in their quality and value for the industry. in order to understand the infection process and formation of kernel spots the objectives of this work were i) to determine the period of kernel's susceptibility during their spot formation by p. chaetomioides on the floral components; ii) to determine the different levels of resistance of 15 oat genotypes to black spot and its correlation with kernel infection; iii) to assess the effect of chemical control on the expression of the disease during the period of kernel formation. in the laboratory, the percentage of spotted grains and the incidence of p. chaetomioides in the floral components was evaluated, whereas in the field, yield and industrial weight were measured. milk and dough stages had the largest incidences of p. chaetomioides in the floral components. the genotypes differed with regard to the black spot symptom on the kernel as well as with the incidence, but no correlation between these two variables was observed. chemical control during the flowering stage reduced in 21% the incidence of the fungus in the seed in relation to the control. despite of this, chemical control was neither efficient enough to reduce spot formation nor to increase yield to compensate its cost.
Estabelecimento de Pyrenophora chaetomioides em cariopses de aveia branca em condi??es de campo
Rosa, Carlos R. E. da;Martinelli, José A.;Federizzi, Luiz C.;Bocchese, Carla A. C.;
Fitopatologia Brasileira , 2003, DOI: 10.1590/S0100-41582003000400018
Abstract: oat (avena sativa) is one of the most important crops in south brazil. as acreage increases, particularly in the no-till system, some diseases became more significant. in order to identify which growth stage of the kernel is more susceptible to the establishment of the fungus pyrenophora chaetomioides, three experiments were conducted under field conditions. oat panicles were exposed to natural inoculum during specific periods of time from their extrusion. to protect the panicles from the inoculum, cellophane bags were used to cover them. at the end of the cycle the panicles were individually harvested and the percentage of infected kernels was calculated after plating them in an artificial medium. the kernels exposed to the inoculum during the milk and dough stages showed the highest percentages of infection. temperature and precipitation did not contribute to the infection, although high temperature and precipitation along with occurrence of other diseases anticipated the senescence of basal leaves, favoring the inoculum production.
Quantifica??o dos conídios produzidos por Pyrenophora chaetomioides em folhas mortas de Avena sativa em condi??es de campo
Rosa, Carlos R. E. da;Martinelli, José A.;Federizzi, Luiz C.;Bocchese, Carla A. C.;
Fitopatologia Brasileira , 2003, DOI: 10.1590/S0100-41582003000300017
Abstract: efforts were made to quantify the production of pyrenophora chaetomioides conidia on basal, dead oat leaves and to correlate it with temperature and precipitation during the crop season. at regular intervals of time samples of dead leaves were harvested from the surface of the plots, and the conidia were counted in the laboratory. the results showed that conidia decreased as the sowing date was delayed and that spore production was higher on the early variety than on the later ones. there was an association between the accumulated precipitation in the previous period of the harvested sample and the conidia produced.
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