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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.
41

Curvas de progresso de doenças foliares do milho, sob diferentes tratamentos fungicidas /

Costa, Frank Magno da. January 2007 (has links)
Orientador: Modesto Barreto / Banca: Margarete Camargo / Banca: Érika Auxiliadora Giacheto Scaloppi / Resumo: Representando cerca de 35,6% da safra de grãos do país, a cultura do milho tem sua produtividade ameaçada por um grande número de enfermidades. Diante do exposto o presente trabalho teve por objetivo analisar o progresso da Physopella zeae, Cercospora zeae-maydis e Phaeosphaeria maydis, sob diferentes tratamentos fungicidas na cultura do milho. Conduzido no delineamento de blocos casualizados com 6 tratamentos e 4 repetições em área do Departamento de Fitossanidade da FCAV-UNESP, utilizou-se os seguintes tratamentos de 1-6 (mL de p.c./ha), respectivamente: 1-testemunha; 2-epoxiconazole + pyraclostrobin 500; 3- epoxiconazole + pyraclostrobin 750; 4-azoxystrobin + cyproconazole 300 + óleo mineral parafínico 0,5%; 5-azoxystrobin + cyproconazole 300 + óleo mineral parafínico 0,5% e 6- azoxystrobin + cyproconazole 450 + óleo mineral parafínico 0,5%, todos aplicados com a planta no estádio V8, sendo que o Tratamento 5 foi repetido com a planta no início do pendoamento. Realizou-se 7 avaliações de severidade da doença com intervalos semanais. As curvas de progresso da doença foram analisadas através de 3 transformações (monomolecular, logístico e de Gompertz). Calculou-se a Área Abaixo da Curva de Progresso da Doença (AACPD) para cada doença, estas foram submetidas à análise de variância e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade. Observou-se que o modelo monomolecular foi o que melhor se ajustou aos dados para a P. zeae e para a C. zeae-maydis. Em se tratando de P. maydis o modelo logístico proporcionou melhor ajuste...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The corn represents about 35,6% grain crop in Brazil and its productivity is threatened by a great number of pests and diseases. The objective of this study was to analyze the progress of the Physopella zeae, Cercospora zeae-maydis and Phaeosphaeria maydis, under different fungicides treatments in the corn crop. This work was carried out in experimental area of the Departamento de Fitossanidade of UNESP, Campus of Jaboticabal, São Paulo State, Brasil, in the period of January to May of 2006. Was evaluated in field plots arranged in complete randomized blocks, with 6 treatments and 4 replications. The used treatments were (mL of p.c. /ha): 1-check; 2-epoxiconazole + pyraclostrobin 500; 3-epoxiconazole + pyraclostrobin 750; 4-azoxystrobin + cyproconazole 300 + mineral oil 0,5%; 5-azoxystrobin + cyproconazole 300 + mineral oil 0,5% and 6 - azoxystrobin + cyproconazole 450 + mineral oil 0,5%. All the treatments fungicide spray was applied to maize at the stage V8, and the treatment 5 was replicated in the beginning of the tasseling. It was carried out 10 evaluations of the disease severity with a week interval among them. It was analyzed the curves of progress of the diseases through 3 transformations (monomolecular, logistic and Gompertz). There was calculated Area Under Progress Curve Disease (AUDPC), whose the variance analysis and the averages were compared by the Tukey test at 5% probability. It was observed that the monomolecular model had the best adjustment to the data for the P. zeae and C. zeae-maydis. For the P. maydis the logistic model had the best adjustment...(Complete abstract, click electronic address below) / Mestre
42

Epidemiologia da mancha de phaeosphaeria e da cercosporiose em milho

Koshikumo, Érica Sayuri Maneti [UNESP] 07 August 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-08-07Bitstream added on 2014-06-13T20:18:16Z : No. of bitstreams: 1 koshikumo_esm_me_jabo.pdf: 514654 bytes, checksum: c6c89f1bd2aafce34a1da5563e125019 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com objetivo de analisar aspectos epidemiológicos da Mancha de Phaeosphaeria (Phaeosphaeria maydis) e da Cercosporiose (Cercospora zeae - maydis) do milho (Zea mays) no município de Capão Bonito/SP de março a agosto de 2002 a 2006, sendo que a primeira ocorreu em todo período de estudo, enquanto a Cercosporiose (Cercospora zeae-maydis) ocorreu em dois anos (2002 e 2004), foram feitos ensaios em Blocos Casualizados com 3 repetições com 42 a 54 cultivares dependendo do ano. Quatro avaliações em todos os ensaios em intervalos semanais utilizando-se escala diagramática proposta pela Agroceres em 1993. Foi calculada a Curva de Progresso da Doença e a Área abaixo da mesma (AACPD), a qual foi analisada pelo teste F e as médias comparadas pelo teste de Scott-Knott. Com base neste teste os cultivares foram divididos em 4 grupos: Resistentes, Moderadamente Resistentes, Moderadamente Suscetíveis e Suscetíveis. Dados climáticos foram correlacionados com a doença. Foram testados os modelos matemáticos: Logístico, Exponencial, de Gompertz e Monomolecular. Sendo que este último foi o que melhor se ajustou aos dados em todos os anos para as duas doenças, tomando por base o R*2 (coeficiente de determinação entre os valores previstos e os observados). O ano de maior severidade para a Mancha de Phaeosphaeria foi o de 2005, enquanto para a Cercosporiose foi de 2002; isto provavelmente é devido às condições climáticas. A maioria dos cultivares se comportou como moderadamente resistente e resistente à Mancha de Phaeosphaeria e a Cercosporiose. Nota-se que nos anos onde a Mancha de Phaeosphaeria e Cercosporiose ocorreram concomitantemente (2002 e 2004), a primeira apresentou em todos os grupos (R, MR, MS e S) maiores severidades e inicio da epidemia mais tardia que a Cercosporiose. Em ambas a diferença de severidade deve-se principalmente à taxa de progresso de doença (r). / With the aim to analyze epidemiological aspects the Phaeosphaeria spot (Phaeosphaeria maydis) and gray leaf spot (Cercospora zeae-maydis) of maize (Zea mays) at Capão Bonito city, from march to august of 2002 to 2006, were studied, as the first occurred in all the period of study, while the gray leaf spot occurred in 2 years (2002 and 2004). The experimental design was casualized blocks with 3 repetitions each and 42 to 54 treatments, depending on the year. Four evaluations were made in weekly intervals using Agroceres diagrammatic scale. The disease progress curve (AUDPC) and its area under it was calculated and submitted to variance analysis (ANAVA) by F test, which averages were compared by Scott-Knott. Based on the results, the cultivars were grouped in resistant, moderately resistant, moderately susceptible and susceptible. Climate data were related to the disease. The logistic, exponential, Gompertz and monomolecular mathematic models were tested, being the monolecular model which better suited the data in all years, for both diseases, based in R*2. The year with higher Phaeosphaeria spot severity was 2005, while for Cercospora leaf spot was 2002, probably caused by climatic conditions. Most varieties were moderately resistant or resistant for Phaeosphaeria spot and Cercospora leaf spot. It was observed that on the years where Phaeosphaeria spot and Cercospora leaf spot occurred concomitantly (2002 and 2004); the first presented in all groups (R, MR, MS and S) higher levels of severity and the delay on the begining of the epidemy compared to Cercospora leaf spot. For both diseases, the difference on the disease progress occured mainly beause of the disease progress rate (r).
43

Curvas de progresso de doenças foliares do milho, sob diferentes tratamentos fungicidas

Costa, Frank Magno da [UNESP] 05 March 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-03-05Bitstream added on 2014-06-13T20:37:27Z : No. of bitstreams: 1 costa_fm_me_jabo.pdf: 412278 bytes, checksum: b137b47f1e7a98ef2356e7beda9b1bee (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Representando cerca de 35,6% da safra de grãos do país, a cultura do milho tem sua produtividade ameaçada por um grande número de enfermidades. Diante do exposto o presente trabalho teve por objetivo analisar o progresso da Physopella zeae, Cercospora zeae-maydis e Phaeosphaeria maydis, sob diferentes tratamentos fungicidas na cultura do milho. Conduzido no delineamento de blocos casualizados com 6 tratamentos e 4 repetições em área do Departamento de Fitossanidade da FCAV-UNESP, utilizou-se os seguintes tratamentos de 1-6 (mL de p.c./ha), respectivamente: 1-testemunha; 2-epoxiconazole + pyraclostrobin 500; 3- epoxiconazole + pyraclostrobin 750; 4-azoxystrobin + cyproconazole 300 + óleo mineral parafínico 0,5%; 5-azoxystrobin + cyproconazole 300 + óleo mineral parafínico 0,5% e 6- azoxystrobin + cyproconazole 450 + óleo mineral parafínico 0,5%, todos aplicados com a planta no estádio V8, sendo que o Tratamento 5 foi repetido com a planta no início do pendoamento. Realizou-se 7 avaliações de severidade da doença com intervalos semanais. As curvas de progresso da doença foram analisadas através de 3 transformações (monomolecular, logístico e de Gompertz). Calculou-se a Área Abaixo da Curva de Progresso da Doença (AACPD) para cada doença, estas foram submetidas à análise de variância e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade. Observou-se que o modelo monomolecular foi o que melhor se ajustou aos dados para a P. zeae e para a C. zeae-maydis. Em se tratando de P. maydis o modelo logístico proporcionou melhor ajuste... / The corn represents about 35,6% grain crop in Brazil and its productivity is threatened by a great number of pests and diseases. The objective of this study was to analyze the progress of the Physopella zeae, Cercospora zeae-maydis and Phaeosphaeria maydis, under different fungicides treatments in the corn crop. This work was carried out in experimental area of the Departamento de Fitossanidade of UNESP, Campus of Jaboticabal, São Paulo State, Brasil, in the period of January to May of 2006. Was evaluated in field plots arranged in complete randomized blocks, with 6 treatments and 4 replications. The used treatments were (mL of p.c. /ha): 1-check; 2-epoxiconazole + pyraclostrobin 500; 3-epoxiconazole + pyraclostrobin 750; 4-azoxystrobin + cyproconazole 300 + mineral oil 0,5%; 5-azoxystrobin + cyproconazole 300 + mineral oil 0,5% and 6 - azoxystrobin + cyproconazole 450 + mineral oil 0,5%. All the treatments fungicide spray was applied to maize at the stage V8, and the treatment 5 was replicated in the beginning of the tasseling. It was carried out 10 evaluations of the disease severity with a week interval among them. It was analyzed the curves of progress of the diseases through 3 transformations (monomolecular, logistic and Gompertz). There was calculated Area Under Progress Curve Disease (AUDPC), whose the variance analysis and the averages were compared by the Tukey test at 5% probability. It was observed that the monomolecular model had the best adjustment to the data for the P. zeae and C. zeae-maydis. For the P. maydis the logistic model had the best adjustment...(Complete abstract, click electronic address below)
44

Caracterização morfológica de cercospora e eficiência da toxina cercosporina na seleção de genótipos de pimenteiras ornamentais / Characterization cercospora morphological and toxin efficiency in genotypes cercosporin selection chili ornamental

Santos, Aline da Silva 29 May 2015 (has links)
Submitted by Katiane Souza (katyane.souza@gmail.com) on 2016-06-05T14:30:20Z No. of bitstreams: 1 arquivototal.pdf: 2173132 bytes, checksum: 26847d26f9234311c1ecbcd39be1a04e (MD5) / Made available in DSpace on 2016-06-05T14:30:20Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2173132 bytes, checksum: 26847d26f9234311c1ecbcd39be1a04e (MD5) Previous issue date: 2015-05-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Cercospora leaf spot is an serious fungal disease of plants of the genus Capscum, it is caused by fungi of genus Cercospora, which produce a toxin, the cercosporin, that has a red coloration which is very toxic to the plant tissues. Therefore, this work purpose was realize a characterization of this disease in ornamental chili plants, as well as, try the efficiency of cercosporin toxin in the genotype of chili ornamental plants. Therefore, it has proceeded an organs collet of infected organs by ornamental chili plants grown in a greenhouse, located in the Science Center Agrarian of Federal University of Paraíba – UFPB/CCA, Campus II, Areia – PB. The samples were taken to the Biotechnology Laboratory of UFPB/CCA for a morphological characterization of the fungus. The disease characterization was did observing plants with symptoms of the disease. To test the efficiency of the cercosporin, it was realized an induction of the production of cercosporin in fungi colonies grown in different in various culture media having as the base coconut milk (LCO), coconut water (ACO), V8 juice (A- V8), leaf extract of pepper (A – P), and water agar (A-A). After that, the toxin was identified throw de change of coloration to green of the fungal solution in contact with the alkaline way, KOH 5N. After this moment of identification, it was realized a quantification and an extraction of cercosporin with the aid of extractor solution Tris-HCl that has pH 6,8. The toxin quantification was made using the Bradford method, proceeding its inoculation in leaves of seven genotypes of chili plants using the concentration that best expressed the symptoms. When the results was analyzed, it has observed that fungous structure was the same kind of the description of the cercospora capsici fungi, which is the responsible for the Cercospora leaf spot has said the Koch postulate. Direct isolation method has given the possibility the achievement of fungus in all plants parts, and, the indirect method have given possibility it with the branches. The water agar base way has promote a bigger mycelial growth, and the leaf extract base way improve a bigger colony proportion. The ACO way has promote the toxin expansion in all Petri dish and has have a bigger quantity of cercosporin for mycelial disc. All the way, except the A-A, has induced a cercosporin produce. The coconut milk base way and the leaf extract with and without gelling present the biggest cercosporina production. The isolated grown in the A-A way has produced quantities of cercosporin equal the isolated grown in the LCO and P-A ways with gelling. The toxin concentrations 40% and 50% showed better the cercosporin symptoms. The UFPB 131, UFPB 132, and UFPB 358 has showed tolerance to the cercosporin toxin. / A cercosporiose é uma grave doença fúngica de plantas do gênero Capsicum, causada por fungos do gênero Cercospora, que se caracterizam por produzir uma toxina, a cercosporina, de coloração vermelha de alta toxidez aos tecidos vegetais. Com isso, o objetivo do trabalho foi realizar a caracterização da doença em plantas de pimenteiras ornamentais, bem como, testar a eficiência da toxina cercosporina na seleção de genótipos de pimenteiras ornamentais. Para isso, procedeu-se a coleta de órgãos infectados de plantas de pimenteiras ornamentais cultivadas em casa de vegetação, no Centro de Ciências Agrárias da Universidade Federal da Paraíba - UFPB/CCA, Campus II, Areia – PB. As amostras foram encaminhadas para o Laboratório de Biotecnologia da UFPB/CCA, para a caracterização morfológica do fungo. A caracterização da doença foi realizada observando plantas com sintomas da doença. Para testar a eficiência da cercosporina, realizou-se a indução da produção de cercosporina em colônias fúngicas cultivadas em diferentes meios de cultura à base de leite de coco (LCO), água de coco (ACO), suco V8 (A-V8), extrato de folhas de pimenteiras (A-P) e água-ágar (A-A). Em seguida, identificou-se a toxina através da mudança de coloração para verde da solução fúngica em contato com o meio alcalino KOH 5N. Após a identificação foi realizada a quantificação e a extração da cercosporina, com auxilio da solução extratora Tris-HCl com pH 6,8. A quantificação da toxina foi feita pelo método de Bradford, procedendo a sua inoculação em folhas de sete genótipos de pimenteiras utilizando a concentração que melhor expressou os sintomas. Analisando os dados, observou-se que estruturas fúngicas presentes em lesões de pimenteiras foram semelhantes às descritas para o fungo Cercospora capsici, e confirmando como causador de cercosporiose pelo postulado de Koch. O método de isolamento direto possibilitou a obtenção do fungo em todas as partes vegetais e o método indireto utilizando os ramos. O meio à base de ágar-água promoveu o maior crescimento micelial e o meio à base de extrato de folhas de pimenteira o maior tamanho da colônia. O meio ACO promoveu a expansão da toxina em toda a placa de Petri e obteve a maior quantidade de cercosporina por disco micelial. Todos os meios, com exceção do meio A-A, induziram a produção de cercosporina. Os meios à base de leite de coco e extrato de folha de pimenteira com e sem geleificante apresentaram as maiores produções de toxina. Os isolados cultivados no meio A-A produziram quantidades de cercosporina iguais aos dos isolados cultivados nos meios LCO e P-A com geleificantes. As concentrações da toxina 40 e 50% foram as que melhor expressaram os sintomas de cercosporiose. Os genótipos UFPB 131, UFPB 132 e UFPB 358 apresentaram tolerância à toxina cercosporina.
45

Characterization of Cytochrome B from European Field Isolates of Cercospora Beticola with Quinone Outside Inhibitor Resistance

Birla, Keshav January 2012 (has links)
Cercospora leaf spot (CLS), caused by the fungal pathogen Cercospora beticola, is the most important foliar disease of sugar beet worldwide. Control strategies for CLS rely heavily on fungicides including quinone outside inhibitor (QOI) fungicides. We collected 866 C. beticola isolates from sugar beet growing regions in France and Italy and assessed their sensitivity to the QOI fungicide pyraclostrobin. To gain an understanding of the molecular basis of QOI resistance, we cloned the full-length coding region of Cbcytb. All tested QOI-resistant isolates harbored a point mutation in Cbcytb at nucleotide position 428 that conferred an exchange from glycine to alanine at amino acid position 143 (G143A). A PCR assay was developed to discriminate QOI-sensitive and QOI-resistant isolates based on the G143A mutation. Our results indicate that QOI resistance has developed in some European C. beticola populations in Italy and monitoring the G143A mutation is an essential fungicide resistance management strategy.
46

Identifying Frogeye Leaf Spot Resistance in Two Elite Soybean Populations and Analysis of Agronomic Traits in Resistant Lines

Smith, Kelsey 01 June 2021 (has links)
Soybeans (Glycine max L.) are an important crop globally for its food, feed, and oilpurposes. It is impacted by many diseases, including Cercospora sojina, the causal agent of Frogeye Leaf Spot (FLS). Chemical and cultural controls to this fungal pathogen are insufficient, so genetic resistance must be acquired for adequate control. To this end, two recombinant inbred populations were screened in a greenhouse setting for their relative resistance to FLS, and their genomes were analyzed for contributing quantitative trait loci (QTL). In the Essex ́ Forrest population, one QTL was discovered on chromosome 13, and in the Forrest ́ Williams 82 population, two QTL were identified on chromosomes 6 and 11, respectively. These populations were then also screened in a field setting for agronomic traits. These traits were analyzed to detect one superior line for both FLS resistance and advanced agronomic traits, F ́W 125. This line should be used in future breeding projects to increase FLS resistance and reduce linkage drag for other desired characteristics.
47

Quantification of Fungicide Resistance in Cercospora sojina Populations and Development of a Fungicide Application Decision Aid for Soybean in the Mid-Atlantic U.S.

Zhou, Tian 09 October 2019 (has links)
Soybean is an important source of protein in animal feed, and growing demand for meat consumption worldwide has led to increased soybean production. Over 120 million metric tons of soybean were harvested in the United States in 2018, approximately one-third of the world production. In the Mid-Atlantic region, soybean is one of the most valuable field crops. Major foliar diseases that reduce soybean yield in the Mid-Atlantic region are frogeye leaf spot (FLS) and Cercospora leaf blight. In addition to crop rotation and host resistance, foliar fungicides, often with quinone outside inhibitor (QoI) active ingredients, are used to manage these soybean foliar diseases. Yield benefits of foliar fungicides have been inconsistent and this may be the result of low disease pressure, unfavorable environmental conditions for disease development, or the presence of fungal pathogen populations that have developed resistance to fungicides. The objectives of this research were 1) to develop a pyrosequencing-based assay to rapidly quantify QoI resistance frequencies in Cercospora sojina, the causal agent of FLS, 2) to examine the effects of fungicide application timings, disease pressure, and environmental factors on soybean yield, and 3) to develop a weather-based soybean foliar fungicide application decision aid for the Mid-Atlantic U.S. using a threshold decision rule. A pyrosequencing assay targeting the G143A mutation was designed, and a Virginia survey of C. sojina populations indicated that the G143A mutation conferring QoI resistance is widespread. In small plot fungicide application timing experiments, five weekly fungicide applications starting at beginning pod (R3) resulted in the greatest yield, but for single fungicide applications, R3 or 1 week after R3 resulted in the greatest yields. There was positive relationship between the cumulative number of disease favorable days (mean daily temperature 20-30°C and ≥ 10 hours of relative humidity >90%) from planting to R3 and disease severity at the full pod stage (r = 0.97, P = <0.01). Higher disease severity was associated with greater yield loss (r2 =0.53, P = 0.10) suggesting foliar fungicide applications are more likely to have yield benefits as the number of disease favorable days prior to R3 increase. A disease favorable-days threshold (FDT) using the environmental parameters indicated above was evaluated in on-farm experiments throughout Virginia, Maryland, and Delaware. Based on decision rules, FDT = 8 three weeks prior to R3 was the best predictor of a yield benefit with an R3 fungicide application. The decision aid was also able to correctly predict when a fungicide application would not be profitable ≥90% of the time. This weather-based decision aid along with monitoring of fungicide resistance development within the region will provide soybean growers in the Mid-Atlantic U.S. with tools to maximize yields and profitability. / Doctor of Philosophy / Soybean is the third most valuable field crop in the world, ranked only behind rice and wheat in value. Over 98% of the soybean crop is used for animal feed due to its high protein content. The United States is the largest soybean producer in the world, responsible for one-third of global production. Soybean is the top cash crop in the Mid-Atlantic region. Foliar fungal diseases can reduce the soybean yield by causing lesions on the leaves that reduce photosynthesis and cause premature defoliation. Frogeye leaf spot (FLS) caused by Cercospora sojina is a major yield reducing soybean foliar diseases in the Mid-Atlantic region. Foliar fungicides, often with quinone outside inhibitor (QoI) active ingredients, are used to manage the disease. However, fungicide efficacy has been inconsistent. Inconsistencies may be due to low disease pressure, improper application timing, or fungicide resistance. The purpose of this research was to investigate the fungicide efficacy inconsistencies and to develop management tools to improve yield and maximize profitability. Our objectives were to 1) develop a molecular assay to quantify frequencies of the mutation conferring fungicide resistance in Virginia populations of C. sojina, 2) examine the effects of fungicide application timings, disease severity, and weather on soybean yield, and 3) develop a weather-based soybean foliar fungicide application decision aid for the Mid-Atlantic U.S. The C. sojina fungicide resistance mutation was widespread in Virginia, but overall frequencies were relatively low compared to findings from Midwest and Southern states. In fungicide timing experiments, beginning pod (R3) applications resulted in the most consistent yield benefits, and disease severity and yield loss increased as the number of weather-based disease favorable days prior to R3 increased. We used data from on-farm experiments in Virginia, Maryland, and Delaware to develop a weather-based disease favorable-days threshold that increased the probability that a fungicide application at R3 would have a yield benefit in soybean. The results of our research have led improved fungal disease management recommendations for soybean in the Mid-Atlantic that will maximize yields and profitability.
48

Método computacional para identificação do fungo Cercospora Kikuchii em sementes de soja / Método computacional para identificação do fungo Cercospora Kikuchii em sementes de soja

Franco, Jaqueline Rissá 29 June 2017 (has links)
Made available in DSpace on 2017-07-21T14:19:31Z (GMT). No. of bitstreams: 1 dissertacao_jaqueline_franco.pdf: 5450978 bytes, checksum: ccba56653d20a1b74e0758541848145a (MD5) Previous issue date: 2017-06-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The condition known as purple spot in soybean seed is caused by the fungus Cercospora kikuchii and can influence both yield and quality losses in the production of soybean derivatives. Seed quality control is essential to avoid such losses, so there are conventional methods, such as visual inspections to identify contaminated seeds. However, these conventional processes are slow and imprecise, since they depend directly on the analyst. The present work had as objective to develop a computational system for the identification of soybean seeds contaminated by the fungus Cercospora kikuchii. The proposed method was developed based on the OpenCV library, using the Java programming language and the integration interface of the WEKA tool. Samples of 150 healthy seeds and 150 contaminated seeds were considered. The individual image acquisition of each seed, for purposes of classification in healthy or contaminated, was performed and was consided in the process the individual quality of each stage. The obtained result was 88% of correct classifications, using crossvalidation in the constructed neural network model and 100% correct classifications in the used images. The best results found in studies of other authors, specifically considering the fungus Cercospora kikuchii, were 66% to 83% of the correct classifications. / A presença da patologia conhecida como mancha púrpura da semente de soja é causada pelo fungo Cercospora kikuchii e pode implicar em prejuízos tanto de produtividade quanto de qualidade na produção de derivados. O controle de qualidade de sementes é essencial para evitar perdas como essas, sendo então convencionalmente realizadas inspeções visuais, para identificar as sementes contaminadas. Porém, tais processos convencionais são lentos e imprecisos, uma vez que depende diretamente do analista. O presente trabalho teve por objetivo desenvolver um sistema computacional para a identificação de sementes de soja contaminadas pelo fungo Cercospora kikuchii. O método proposto foi desenvolvido utilizando a biblioteca OpenCV, por meio da linguagem de programação Java, e utilizando a interface de integração da ferramenta WEKA. Foram consideradas amostras de 150 sementes sadias e de 150 sementes contaminadas. A obtenção individual da imagem de cada semente, para fins de classificação em sadia ou contaminada, foi realizada e foi considerada durante o processo a qualidade individual de cada etapa do processo. O resultado alcançado foi de 88% de assertividade, utilizando a validação cruzada sobre o modelo de rede neural artificial construído, e de 100% de assertividade sobre as imagens utilizadas. Os melhores resultados encontrados em trabalhos de outros autores, considerando especificamente o fungo Cercospora kikuchii, foram de 66% a 83% de assertividade.
49

Epidemiologie von Cercospora beticola Sacc. und Befalls-Verlust-Relationen bei Zuckerrüben (Beta vulgaris L.) in Abhängigkeit von der Anfälligkeit von Sorten und Konsequenzen für sortenspezifische Bekämpfungsschwellensysteme / Epidemiology of Cercospora beticola Sacc. and disease-loss relationship in sugar beet (Beta vulgaris L.) depending on the susceptibility of cultivars and consequences for cultivar specific threshold systems

Kaiser, Ulrike 19 July 2007 (has links)
No description available.
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Comportamento de fungicida em plantas de soja submetidas a diferentes regimes hídricos e horários de aplicação / Performance of fungicide in soybean plants under different water regimes and times of application

Stefanello, Marlon Tagliapietra 21 February 2014 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The climatic factors, especially water deficit, cause changes in biochemical and morphophysiological aspects in soybean plants, which consequently affect the performance of fungicide applications on leaves and pathogenicity of fungi. This study aimed to evaluate the performance of fungicide in soybean under different water regimes and times of application. For this purpose two experiments were conducted, one in the greenhouse and one on the field, both in Itaara RS, Brazil. The experimental design in greenhouse was composed by completely randomized design with four replications in a factorial (2x6x5), which factors were composed, factor 01: two water regimes (50-60% of the field capacity and 90-100% of the field capacity); factor 02: five times of application (04:00 a.m., 09:00 a.m., 14:00 p.m., 18:00 p.m., 23:00 p.m.) and a control without fungicide applying; factor 03: four time periods between the fungicide application and simulated rain (0, 30, 60 and 120 ) plus a control with no rain. Fungicide comprising the active ingredients Trifloxystrobin + Prothioconazole (70.0 + 60.0 g ha-1 a.i.) was used with the addition of Aureo® at a dose of 0.375 l ha-1 c.p. The parameters evaluated were the number of days until the first pustule preview of asian rust, the severity of Phakopsora pachyrhizi and Cercospora kikuchii in leaves, incidence of C. kikuchii in grain, relative chlorophyll content, stomatal density, trichome density, concentration of hydrogen peroxide, lipid peroxidation, yield and grain weight. The experimental design in the field was composed by randomized blocks with split plots. The experiment consisted of two factors (6x5). The first factor was composed of the application time (04:00 a.m., 09:00 a.m., 14:00 p.m., 18:00 p.m., 23:00 p.m.) and a control without fungicide applying. The second factor was composed of the time periods between the fungicide application and simulated rain (0, 30, 60 and 120 ) plus a control with no rain. The parameters evaluated were the severity of the asian rust, the relative chlorophyll content stratified in three thirds of the canopy, area under the disease progress curve, yield and hundred grain weight. The results indicate that the penetration of fungicide is faster in leaflets in sunlight. It finds that the application of fungicides in plants under water deficit provides the greatest number of days until the first pustule preview. The simulated rainfall has a greater effect on the removal of fungicide applications made at night. The fungicide application in leaflets made at 09:00 am provides the greatest number of days until the first pustule preview. Soybean plants in water deficit develop strategies to reduce the loss of water, which affects the pathogenicity of Phakopsora pachyrhizi and Cercospora kikuchii. / Os fatores climáticos, em especial o déficit hídrico, provocam alterações nos aspectos morfofisiológicos e bioquímicos nas plantas de soja, que consequentemente, afetam o comportamento de aplicações fungicidas foliares e a patogenicidade de fungos. O presente trabalho objetivou avaliar o comportamento de fungicida em plantas de soja submetidas a diferentes regimes hídricos e horários de aplicação. Para isso foram conduzidos dois experimentos, sendo um em casa de vegetação e outro à campo, ambos no município de Itaara RS. Em casa de vegetação foi utilizado o delineamento inteiramente casualizado com quatro repetições, em arranjo trifatorial (2x6x5), cujos fatores foram, fator 01: dois regimes hídricos (50-60% da capacidade de campo e 90-100% da capacidade de campo); fator 02: cinco horários de aplicação (04:00, 09:00, 14:00, 18:00, 23:00 horas), além de um testemunha sem aplicação; fator 03: quatro intervalos de tempo entre a aplicação de fungicida e a aplicação de chuva simulada (0, 30, 60 e 120 min) mais uma testemunha sem chuva. Foi utilizado o fungicida composto pelos ingredientes ativos Trifloxistrobina + Protioconazol (70,0 + 60,0 g i.a.ha-1) com adição de Aureo® na dose de 0,375 L p.c ha-1. Os parâmetros avaliados foram o tempo decorrido entre a aplicação e o surgimento da primeira pústula de ferrugem asiática, a severidade de Phakopsora pachyrhizi e Cercospora kikuchii em folhas, incidência de C. kikuchii em grãos, teor relativo de clorofila, densidade estomática, densidade de tricomas, concentração de peróxido de hidrogênio e peroxidação lipídica, produtividade e a massa de grão. À campo foi utilizado o delineamento experimental de blocos ao acaso com parcelas subdivididas. O experimento constituiu-se de dois fatores (6x5). O primeiro fator foi composto pelos horários de aplicação (04:00, 09:00, 14:00, 18:00, 23:00 horas), e uma testemunha sem aplicação de fungicida. O segundo fator foi composto pelos intervalos de tempo entre a aplicação de fungicidas e a simulação de chuva (2, 30, 60 e 120 min), mais uma testemunha sem chuva. Os parâmetros avaliados foram a severidade de ferrugem asiática e o teor relativo de clorofila estratificados nos três terço do dossel, área abaixo da curva de progresso da doença, produtividade e massa de 100 grãos. Os resultados obtidos indicam que a penetração de fungicida é mais rápida em trifólios sob luz solar. Verifica-se que a aplicação de fungicida em plantas sob déficit hídrico proporciona o maior número de dias para o aparecimento da primeira pústula. A simulação de chuva tem maior efeito na remoção de fungicidas em aplicações realizadas à noite. A aplicação de fungicida em trifólios realizada às 09:00 horas proporciona o maior número de dias para o aparecimento da primeira pústula. As plantas de soja em déficit hídrico desenvolvem estratégias para reduzir a perda de água, o que afeta a patogenicidade de Phakopsora pachyrhizi e Cercospora kikuchii.

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