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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Interferência de patógenos nos resultados dos testes de vigor em sementes de feijoeiro

Frigeri, Thaís [UNESP] 27 February 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-27Bitstream added on 2014-06-13T19:16:23Z : No. of bitstreams: 1 frigeri_t_me_jabo.pdf: 214550 bytes, checksum: a1c65c9e88fd5fc622a8f30d3f3a9e22 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo dessa pesquisa foi verificar a influência de Macrophomina phaseolina, Colletotrichum dematium f. truncata e Colletotrichum lindemuthianum na qualidade fisiológica de sementes de feijoeiro, em especial nos resultados do teste de condutividade elétrica. Foram utilizadas sementes das cultivares Carioca e FT Nobre. As sementes foram infectadas com os fungos em meio de cultura BDA sem e com restrição hídrica (acrescido de manitol a -1,0 MPa). Nos tratamentos testemunhas foram utilizados os mesmos meio de cultura, porém, sem a presença dos fungos. Para cada tratamento as sementes foram sobrepostas nos meios de cultura por 16 horas para M. phaseolina e por 48 horas para o caso de C. dematium f. truncata e C. lindemuthianum. Após secagem natural foram realizados testes de sanidade, germinação em areia e de vigor, como, índice de velocidade de emergência, peso da matéria seca da plântula, teste de frio, teste de envelhecimento acelerado e condutividade elétrica. Também foram realizadas análises na água de embebição das sementes no teste de condutividade elétrica, determinando-se as concentrações de potássio, cálcio e magnésio, assim como nos meios de cultura utilizados com e sem a sobreposição de sementes, para verificação da hipótese de consumo de nutrientes das sementes pelos fungos... / The aim of this research was to verify the influence of Macrophomina phaseolina, Colletotrichum dematium f. truncata and Colletotrichum lindemuthianum in the physiological quality of bean seeds, special in the results of electrical conductivity test. There were used seeds from Carioca and FT Nobre cultivars. The seeds were artificially inoculated with fungi M. phaseolina, C. dematium f. truncata and C. lindemuthianum in BDA medium culture with and without hydric restriction (it was added -1,0 MPa manitol). In the control treatment there was used the same medium culture without the presence of the fungi. For each treatment the seeds were placed on the medium culture for 16 hours for M. phaseolina and 48 hours for C. dematium f. truncata and C. lindemuthianum. After a nature dry, seeds were evaluated, by the blotter test, sand germination and vigor tests: speed of emergence index, seedlings dry weigh, cold, accelerated aging and electrical conductivity tests. Analyses from the imbibition water of the seeds in the electrical conductivity test, were also done a measuring of concentrations of potassium, calcium and magnesium, as well as in the medium culture used with and without the seeds, to verify the hypothesis of seeds nutrients consumption by the fungi...(Complete abstract, click electronic address below)
22

Seleção de genótipos de guandu para resistência a Macrophomina phaseolina e esporulação do fungo

Rosa, Janicéli [UNESP] 15 May 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-15Bitstream added on 2014-06-13T20:58:17Z : No. of bitstreams: 1 rosa_j_me_jabo.pdf: 154567 bytes, checksum: 0d2897a42007e37a9a5f314b75f0f0f0 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) / Objetivou-se o ajuste de metodologia e seleção de genótipos de guandu para resistência a Macrophomina phaseolina a partir de material obtido pela Embrapa Pecuária Sudeste, e verificar o desenvolvimento micelial e esporulação do fungo em meios de cultura. O trabalho foi conduzido em casa de vegetação na UNESP/Jaboticabal no período de agosto de 2004 a dezembro de 2005. Para o ajuste de metodologia e seleção de genótipos resistentes ao fungo as sementes foram submetidas a escarificação com lixa d'água e inoculação artificial através do método de exposição das mesmas ao patógeno por diferentes períodos, que variaram de O a 72 horas. Foram avaliadas porcentagem de plantas sobreviventes e massa fresca. Já para o crescimento micelial e esporulação do fungo foi utilizado o método de sobreposição de discos de diferentes hospedeiros no meio de cultura. A escarificação das sementes contribuiu para a penetração do fungo nas mesmas o período de 24h de exposição das sementes ao fungo são suficientes para detectar diferenças no grau de resistência dos genótipos. Os genótipos mais resistentes são g167-97, g124-95, g27-94, g40-95, g154-95, g127-97 e g9m-97, e os mais suscetíveis são g48-95, g123-95, g8-95, g168-99 e g1m-95. A sobreposição de discos foliares de guandu em meio BDA e folha de papel de filtro em meio sojinha proporcionam um incremento na esporulação de M. phaseolina. / This work had the objective of determining the best schedule for artificial inoculation and select pigeon pea genotypes resistant to Macrophomina phaseolina in material obtained by Embrapa Pecuária Sudeste, and verify the mycelial growth and sporulation of the fungi in middle of culture. The work were carried in greenhouse at the UNESP/Jaboticabal, from August 2004 to December 2005. For the methodology and selection adjustment of resistant genotypes to the fungi the seeds were submitted scarified with water sandpaper and artificial inoculation the seeds were the contact method to fungi for different periods, which varied from O to 72 hours. They were evaluated percentage of surviving plants and fresh mass. For the mycelial growth and sporulation of the fungi was used the superposition of disks method of different hosts in the middle of culture. The scarified of the seeds contributed for penetration of the fungi at the seeds; the period of 24h of contact of the seeds to the fungi enough to detect differences in the resistance degree ofthe genotypes. The genotypes g167-97, g124-95, 927-94, g40-95, g154-95, g127-97 and g9m-97 were found to be the most resistant and most susceptible were g48-95, g123-95, g8-95, g168-99 and g1m-95. The treatment with superposition of the leaf disks of pigeon pea in BDA and disks of filter paper in middle of soybean extract were the treatments that provided better sporulation levei in the conditions of that experiment were half.
23

Controle de Macrophomina phaseolina em soja por extrato de alecrim e análise dos mecanismos de defesa envolvidos

Lorenzetti, Eloísa 10 February 2017 (has links)
Submitted by Helena Bejio (helena.bejio@unioeste.br) on 2017-11-23T17:51:39Z No. of bitstreams: 2 Eloisa Lorenzetti 2017.pdf: 1638897 bytes, checksum: 37d0d636adf093d3df43c201d58eeb5b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-11-23T17:51:39Z (GMT). No. of bitstreams: 2 Eloisa Lorenzetti 2017.pdf: 1638897 bytes, checksum: 37d0d636adf093d3df43c201d58eeb5b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Several works using extracts obtained from medicinal plants have demonstrated direct and potential antimicrobial action to induce the accumulation of secondary metabolites, which are very important as plant defense mechanisms against pathogens. The objective of this work was to develop an alternative method using rosemary extract (Rosmarinus officinalis L.) at concentrations 0%, 1%, 2.5% and 5%, to verify the antimicrobial activity against Macrophomina phaseolina, control of charcoal rot in soybean stem and determine the activity of peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase (PAL) and protein content on soybean plants. We performed in vitro assays in order to analyze mycelial growth of the fungus, fungus mass and number of micro-sclerotia, greenhouse tests to evaluate the area under the disease progress curve (AUDPC), and biochemical analyzes to verify a possible induction of resistance in the treated plants. For the determination of the defense enzymes, soybean plants were treated with the extracts and inoculated with M. phaseolina. Samples were collected at 0, 36, 72, 120, 168, 216 and 264 h after treatment. The rosemary extract reduced by 44% and 74% the fungal growth on solid and liquid media, respectively, while for the micro-sclerotia the reduction was of 61%. For the AUDPC in the first and in second assays, there were a reduction of 53% and 56% respectively in the disease. For the samples collected at the base of steam, peroxidase had the highest concentrations of the extract with two peaks of induction. The polyphenol oxidase activity increased from 36 to 120 hours after treatment with extract at 5%. PAL activity was induced only with 5% extract, with increases 83% and 130% higher in times 168 and 216 hours after treatment, respectively. For enzymes activities in root, peroxidase again showed two peaks for increase at 5% concentration, polyphenol oxidase was 426% higher at 216 hours after treatment and PAL showed an increase of 340% at 216 hours after treatment with 5% extract. These results indicate potential of rosemary extract in the control of charcoal rot in soybean and in the induction of plant defense enzymes in soybean. / Diversos trabalhos utilizando extratos obtidos de plantas medicinais têm demonstrado ação antimicrobiana direta e potencial de induzir o acúmulo de metabólitos secundários, sendo estes muito importantes nos principais mecanismos de defesa das plantas aos patógenos. O objetivo deste trabalho foi desenvolver um método alternativo através da utilização do extrato de alecrim (Rosmarinus officinalis L.), nas concentrações 0%, 1%, 2,5% e 5%, para verificar a atividade antimicrobiana contra Macrophomina phaseolina, controlar a podridão cinzenta da haste em soja e determinar as atividades de peroxidase, polifenoloxidase, fenilalanina amônia-liase e teor de proteína de plantas de soja tratadas. Foram realizados ensaios in vitro a fim de analisar o crescimento micelial do fungo, a massa do fungo e o número de microescleródios, ensaios in vivo em casa de vegetação para avaliar a área abaixo da curva de progresso da doença (AACPD), além de análises bioquímicas para verificar uma possível indução de resistência nas plantas tratadas. Para determinação das enzimas de defesa, plantas de soja foram tratadas com os extratos e inoculadas com M. phaseolina, sendo retiradas amostras para análise nos tempos 0, 36, 72, 120, 168, 216 e 264 h após o tratamento. O extrato de alecrim reduziu em até 44% e 74% o crescimento fúngico em meios sólido e líquido, respectivamente, enquanto que para micro-escleródios a redução foi de 61%. Para AACPD, no primeiro e no segundo ensaios houve redução de 53% e 56% respectivamente. Nas amostras retiradas do colo das plantas, para peroxidase, as concentrações mais elevadas do extrato proporcionaram dois picos de indução. Houve constante incremento na atividade de polifenoloxidase desde 36 até 120 h após o tratamento para a concentração 5% do extrato de alecrim. Para FAL apenas a concentração 5% promoveu incremento 83% e 130% maior nos tempos 168 e 216 h após o tratamento, respectivamente. Para as atividades na raiz, a peroxidase novamente apresentou dois picos de incremento para a concentração 5% do extrato, a polifenoloxidase foi 426% maior na concentração 5% às 216 h após o tratamento e a atividade de FAL apresentou incremento de 340% no tempo 216 h após o tratamento com 5% do extrato. Estes resultados indicam potencial do extrato de alecrim no controle de podridão cinzenta da haste em soja e na indução da atividade de enzimas de defesa em colo e raiz de soja.
24

Evaluation of Host Resistance and the Utilization of Organic Amendments to Manage Macrophomina Crown Rot of Strawberry in California

Winslow, Jonathan W 01 June 2019 (has links)
The production of strawberries can be severely limited by soilborne plant pathogens, insects and weeds. Macrophomina phaseolina is a problematic soilborne fungal pathogen in California strawberry production inciting the disease Macrophomina crown rot. When established, the pathogen can cause extensive plant decline and mortality. Host resistance will be a critical tool for managing this disease and guiding breeding programs in the post methyl bromide era. Evaluation of host resistance in strawberry germplasm to M. phaseolina was evaluated through phenotypic assessments of disease incidence. A total of 90 strawberry cultivars and elite selections were included in a replicated field trial conducted in artificially inoculated soils to assess host resistance. Significant differences in levels of resistance and susceptibility were observed among genotypes tested in this trial. The five most resistant strawberry genotypes from highest to lowest in percent plant mortality were: UC-R, UC-G, UC-V, Manresa, and Osceola. The five most susceptible strawberry genotypes with the highest percent mortality in ranking order from highest to lowest were: UC-J, Ruby June, Festival, UC-Y, and UC-A. Of the genotypes tested in this trial UC-V, Manresa and Osceola could be characterized as highly resistant, but no complete resistance was observed. An additional study was conducted to correlate host symptom expression with the extent of pathogen colonization in different strawberry tissues, and to determine if resistant germplasm can contribute to secondary inoculum production in the field. An established qPCR method was utilized to quantify M. phaseolina colonization of strawberry tissues. There were significant effects for cultivar (P < 0.0001) as well as a significant two-way interaction of cultivar x sample time (P= 0.0083) on the concentration of M. phaseolina DNA detected in strawberry tissues. Expression of the resistant phenotype in strawberry cultivars was associated with limited plant colonization by M. phaseolina. The extent of colonization of a specific cultivar by M. phaseolina was dependent on the sample time after inoculation with the pathogen. In addition, the roots and crowns of a specific strawberry cultivar were equally colonized on a per plant tissue weight basis, but this provides only speculation into the mechanisms conferring host resistance. A third study was conducted to integrate host resistance of strawberry genotypes with the use of organic amendments in effort to mutually enhance the efficacy of each factor for the control of Macrophomina crown rot. Artificially inoculated potting substrate was amended with Brassica juncea mustard seed meal at a rate of 4.94 tons ha-1(MSM), and anaerobic soil disinfestation utilizing rice bran at a rate of 22.24 tons ha-1 (ASD) were compared to a non-amended (UTC) and steam controls. The soil assay indicated that the ASD and steam treatments were able to reduce the CFU g-1 potting substrate of M. phaseolina by 99.7-100%. In addition, there were significant effects of soil treatment on the fresh biomass of weed seedlings recovered from the potting substrate. However, disease severity and host colonization of multiple strawberry cultivars by M. phaseolina was not reduced when grown in the treated potting substrate. The effect of strawberry cultivar on the extent of pathogen colonization was highly significant (P < 0.0001), in which cultivars characterized as resistant from phenotypic screenings possessed lower concentrations of M. phaseolina DNA. The suppression of M. phaseolina in response to organic amendments was limited but this study supports findings from previous experiments that genotype specific host resistance minimizes host colonization and reduces the production of secondary inoculum.
25

Inibição do crescimento micelial de Macrophomina phaseolina (Tassi.). Goid por óleos vegetais. / Inhibition of mycelial growth of Macrophomina phaseolina (Tassi.).

UGULINO, Andressa Lacerda Nóbrega 03 May 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-03T18:31:57Z No. of bitstreams: 1 ANDRESSA LACERDA NÓBREGA UGULINO - DISSERTAÇÃO PPGSA ACADÊMICO 2017..pdf: 676544 bytes, checksum: 0dd2e41c1011a60929ca0702449f6287 (MD5) / Made available in DSpace on 2018-05-03T18:31:57Z (GMT). No. of bitstreams: 1 ANDRESSA LACERDA NÓBREGA UGULINO - DISSERTAÇÃO PPGSA ACADÊMICO 2017..pdf: 676544 bytes, checksum: 0dd2e41c1011a60929ca0702449f6287 (MD5) Previous issue date: 2017 / O fungo Macrophomina phaseolina (Tassi.). Goid é o agente etiológico de uma das principais doenças na cultura do feijão-caupi, vulgarmente conhecida como podridão cinzenta do caule. Em decorrência da falta de produtos fitossanitários registrados para o controle desta doença um aumento na busca por métodos de controle alternativo é cada vez mais comum. O objetivo do presente trabalho foi avaliar o efeito de óleos essenciais sobre o crescimento micelial do fungo M. phaseolina. Os óleos testados foram de hortelã (Mentha sp.), eucalipto (Eucalyptus spp.), copaíba ( Copaifera sp.) e alecrim-da-chapada (Lippia gracilis), nas concentrações 0,4; 0,6; 0,8 e 1,0%. Os óleos foram incorporados ao meio de cultura do tipo BDA e posteriormente vertidos em placas de Petri de 90x15mm, após a solidificação do meio, discos de 8mm contendo o micélio do patógeno foram repicados para as placas com os respectivos tratamentos. O experimento foi conduzido no delineamento experimental inteiramente casualizado (DIC) em arranjo fatorial 4 x 4 + 1 +1, sendo dezesseis tratamentos mais uma testemunha negativa e uma testemunha positiva que constou da aplicação suplementar no meio (BDA) do fungicida Sportak 450 EC (Procloraz), e cinco repetições, totalizando 90 parcelas experimentais. Posteriormente todas as placas foram transferidas para incubadora do tipo B.O.D. (biochemical oxygen demand) a 27 ± 2 ºC. Foram realizadas medições diárias do diâmetro da colônia em dois sentidos perpendiculares até que tomasse toda a superfície do meio de cultura de uma das placas. Os dados obtidos foram interpretados por meio de análise de variância não paramétrica e as médias foram comparadas pelo teste de Kruskal-wallis, a 5% de probabilidade de erro e Scott Knott a 5% de probabilidade nos casos em que existiram diferenças significativas e normalidade dos dados. Os óleos essenciais de hortelã e alecrimda-chapada apresentaram melhores resultados quanto a inibição do crescimento micelial, enquanto que os óleos de eucalipto e copaíba apesar de potencialmente promissores, apresentaram inibição intermediária do crescimento micelial do fungo. / Macrophomina phaseolina (Tassi.). Goid is the etiological agent of one of the major diseases in cowpea bean crop, commonly known as gray rot stem. Due to the lack of registered phytosanitary products to control this disease, the search for alternative control methods is increasingly common. The objective of this study was to evaluate the effect of essential oils on the mycelial growth of M. phaseolina. The oils tested were Mentha sp.,Eucalyptus spp., Copaifera sp., and Lippia gracilis at concentrations of 0.4; 0.6; 0.8 and 1.0%. The work was conducted in Phytopathology Laboratory of the Federal University of Campina Grande. Daily measurements of the colony diameter were performed in two perpendicular directions until it filled the entire surface of the culture medium of one of the plates. The experiment was conducted in a completely randomized experimental design in a factorial arrangement 4 x 4 + 1+1, with sixteen treatments plus one negative control and one positive control, which consisted of the supplemental application in the medium (BDA) of the fungicide Sportak 450 EC (Procloraz), and five replications, totaling 90 experimental plots. The data were interpreted through non-parametric analysis of variance and the means were compared by the Kruskal-wallis test, with a 5% probability of error and Scott Knott at 5% probability in cases where there were significant differences and data normality. The Mentha sp. essential oil and Lippia gracilis showed better results in inhibiting mycelial growth, while the Eucalyptus essential oil and Copaifera, although potentially promising, showed intermediate inhibition of fungal mycelial growth.

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