Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-09Bitstream added on 2014-06-13T19:13:48Z : No. of bitstreams: 1 silva_es_me_botfca.pdf: 2204058 bytes, checksum: 3b9b852e779ccf23c221c712179cfa66 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O controle químico tem sido utilizado freqüentemente com baixa eficiência para o fungo Didymella bryoniae, causador da doença crestamento gomoso ou cancro da haste em meloeiro. Porém, alternativas de controle como uso da enxertia e manipulação da nutrição devem ser estudadas. Avaliou-se porta-enxertos e concentrações de potássio na resistência de meloeiro rendilhado a Didymella bryoniae em ambiente protegido. No primeiro experimento, quatro porta-enxertos (melão „Dinero‟, melancia „Ojakkyo‟, abóbora „Strong Tosa‟ e cabaça „Calabash TI-191‟) foram inoculados com discos de micélio (7 mm de diâmetro) de quatro isolados de Didymella bryoniae (Dbr 34, Dbr 36, Dbr 37 e Dbr 39) em caule previamente ferido. Baseado no tamanho da lesão, o porta-enxerto „Dinero‟ foi susceptível, „Strong Tosa‟ moderadamente resistente, „Ojakkyo‟ e „Calabash TI-191‟ resistentes e o isolado Dbr 37 se mostrou mais agressivo dentre os isolados. No segundo experimento, o híbrido de meloeiro „Bônus II‟ foi enxertado nos porta-enxertos „Dinero‟ e „Strong Tosa‟, inoculadas com o isolado Dbr 37 do fungo e submetidas a diferentes concentrações de potássio (0; 62,5; 125; 187,5; 250 mg L-1), tanto plantas enxertadas como pé-franco. As plantas do híbrido „Bônus II‟ enxertadas foram resistentes ao fungo e as pé-franco susceptíveis. As concentrações de potássio não influenciaram no tamanho da lesão e na sobrevivência das plantas, porém influenciaram na condutância estomática e transpiração das plantas. / Chemical control of the fungus Didymella bryoniae, causal agent of gummy stem blight of melon, is frequently inefficient. Alternative methods as grafting on resistant rootstocks and nutrition handling must be studied. Different rootstocks and potassium concentrations were tested to control the disease on net melon grown under plastic house conditions. In a first experiment four rootstocks (melon „Dinero‟, watermelon „Ojakkyo‟, squash „Strong Tosa‟ and calabash „TI-191‟) were tested for resistance inoculated by disks mycelium (7 mm diameter) with four isolates ( Dbr 34, Dbr 36, Dbr 37 and Dbr 39) of D. bryoniae in stem previously injured. Based on lesion size „Dinero‟ proved to be susceptible to the fungus, „Strong Tosa‟ moderately resistant and „Ojakkyo‟ and „TI-191‟ resistant and the isolated Dbr 37 proved more aggressive among isolates. In a second experiment hybrid net melon „Bonus II‟ was grafted on rootstocks „Dinero‟ and „Strong Tosa‟, inoculated with isolate Dbr 37 of the fungus and submitted to different potassium concentration (0; 62,5; 125; 187,5; 250 mg L-1), inoculated both grafted plants as non grafted. Grafted plants of „Bonus II‟ were resistant to the fungus and the non grafted ones susceptible. Potassium concentrations did not influenced size of the lesion on the stem and also in the plants survival, however influence on stomatal conductance and transpiration plants.

Made available in DSpace on 2014-06-11T19:26:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-05Bitstream added on 2014-06-13T20:15:24Z : No. of bitstreams: 1 santos_rl_me_botfca.pdf: 445446 bytes, checksum: 519c1f4ba1fef0646cb280c8d0582ec6 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A ervilha (Pisum sativum L.) é um dos alimentos mais produzidos no mundo. Uma das principais doenças que ocorrem na cultura é o oídio, causada por Erysiphe pisi DC. O controle da doença tem sido realizado por meio de pulverizações com fungicidas, no entanto, o uso de cultivares resistentes deve ser pensado como uma alternativa viável e de efetivo controle no manejo da doença. O trabalho objetivou elucidar a herança da resistência ao oídio na cultivar de ervilha MK-10 e caracterizar alguns aspectos histológicos da infecção de E. pisi nessa cultivar. Para o estudo da herança, as gerações F1, F2, retrocuzamentos e geração F3 de MK-10 com duas populações suscetíveis foram avaliadas em ambiente protegido e a epidemia foi aberta. Nas avaliações histológicas, os seguintes parâmetros foram avaliados: % de germinação dos conídios, % de conídios germinados que formaram apressório, % de conídios germinados com apressório que estabeleceram colônia (% colonização) e número de haustórios por colônia. Para comparar as razões de segregação obtidas no estudo da herança da resistência, adotou-se o teste do Qui-quadrado (X²) e para os dados das análises histológicas, utilizou-se o teste Tukey a 5% de probabilidade. Com base nas segregações obtidas no estudo da herança e nas análises histológicas realizadas, concluiu-se que a resistência de MK-10 ao oídio é devida a um par de alelos recessivos, provavelmente o er1er1 e que a resistência é expressa na fase de pré-penetração, completada por uma morte celular localizada pós-penetração. / The pea (Pisum sativum L.) is the most produced foods in the world. One of the main diseases that occur in the culture is the powdery mildew, caused for Erysiphe pisi DC. The control of the disease has been carried through by means of sprayings with fungicides, however, the use to cultivars resistants must be thought as a viable alternative and of effective control about the handling of the disease. The work objectified to elucidate the inheritance of the resistance to powdery mildew in cultivar of pea MK-10 and to characterize some histological aspects of the infection of E. pisi in this cultivar. For the study of the inheritance, the F1, F2, generations, backcrosses and F3 generations of MK-10 with two susceptible populations had been evaluated in protected environment, the epidemic were open. In the histological evaluations, the following parameters had been evaluated: percentage of germination, percentage of germinated sporelings forming aprressorium, percentage of germinated sporelings with appressorium that established a colony (% colonization) and number of haustoria for colony. To compare the gotten reasons of segregation in the study of the inheritance of the resistance, the test of Qui-square (X²) was adopted and for the data of the histological analyses, the Tukey test was used 5% of probability. On the basis of the segregations gotten in the study of the inheritance and the carried through histological analyses, were concluded that the resistance of MK-10 to the powdery mildew must to a pair of recessive alleles probably er1er1 and that the resistance is express in the pre-penetration phase, completed for a cellular death located post-penetration.

Resumo: A ervilha (Pisum sativum L.) é um dos alimentos mais produzidos no mundo. Uma das principais doenças que ocorrem na cultura é o oídio, causada por Erysiphe pisi DC. O controle da doença tem sido realizado por meio de pulverizações com fungicidas, no entanto, o uso de cultivares resistentes deve ser pensado como uma alternativa viável e de efetivo controle no manejo da doença. O trabalho objetivou elucidar a herança da resistência ao oídio na cultivar de ervilha MK-10 e caracterizar alguns aspectos histológicos da infecção de E. pisi nessa cultivar. Para o estudo da herança, as gerações F1, F2, retrocuzamentos e geração F3 de MK-10 com duas populações suscetíveis foram avaliadas em ambiente protegido e a epidemia foi aberta. Nas avaliações histológicas, os seguintes parâmetros foram avaliados: % de germinação dos conídios, % de conídios germinados que formaram apressório, % de conídios germinados com apressório que estabeleceram colônia (% colonização) e número de haustórios por colônia. Para comparar as razões de segregação obtidas no estudo da herança da resistência, adotou-se o teste do Qui-quadrado (X²) e para os dados das análises histológicas, utilizou-se o teste Tukey a 5% de probabilidade. Com base nas segregações obtidas no estudo da herança e nas análises histológicas realizadas, concluiu-se que a resistência de MK-10 ao oídio é devida a um par de alelos recessivos, provavelmente o er1er1 e que a resistência é expressa na fase de pré-penetração, completada por uma morte celular localizada pós-penetração. / Abstract: The pea (Pisum sativum L.) is the most produced foods in the world. One of the main diseases that occur in the culture is the powdery mildew, caused for Erysiphe pisi DC. The control of the disease has been carried through by means of sprayings with fungicides, however, the use to cultivars resistants must be thought as a viable alternative and of effective control about the handling of the disease. The work objectified to elucidate the inheritance of the resistance to powdery mildew in cultivar of pea MK-10 and to characterize some histological aspects of the infection of E. pisi in this cultivar. For the study of the inheritance, the F1, F2, generations, backcrosses and F3 generations of MK-10 with two susceptible populations had been evaluated in protected environment, the epidemic were open. In the histological evaluations, the following parameters had been evaluated: percentage of germination, percentage of germinated sporelings forming aprressorium, percentage of germinated sporelings with appressorium that established a colony (% colonization) and number of haustoria for colony. To compare the gotten reasons of segregation in the study of the inheritance of the resistance, the test of Qui-square (X²) was adopted and for the data of the histological analyses, the Tukey test was used 5% of probability. On the basis of the segregations gotten in the study of the inheritance and the carried through histological analyses, were concluded that the resistance of MK-10 to the powdery mildew must to a pair of recessive alleles probably er1er1 and that the resistance is express in the pre-penetration phase, completed for a cellular death located post-penetration. / Orientador: Marcelo Agenor Pavan / Coorientador: Norberto da Silva / Banca: Tiyoko Nair Hojo Rebouças / Banca: Edson Luiz Furtado / Mestre

Resumo: O controle químico tem sido utilizado freqüentemente com baixa eficiência para o fungo Didymella bryoniae, causador da doença crestamento gomoso ou cancro da haste em meloeiro. Porém, alternativas de controle como uso da enxertia e manipulação da nutrição devem ser estudadas. Avaliou-se porta-enxertos e concentrações de potássio na resistência de meloeiro rendilhado a Didymella bryoniae em ambiente protegido. No primeiro experimento, quatro porta-enxertos (melão „Dinero‟, melancia „Ojakkyo‟, abóbora „Strong Tosa‟ e cabaça „Calabash TI-191‟) foram inoculados com discos de micélio (7 mm de diâmetro) de quatro isolados de Didymella bryoniae (Dbr 34, Dbr 36, Dbr 37 e Dbr 39) em caule previamente ferido. Baseado no tamanho da lesão, o porta-enxerto „Dinero‟ foi susceptível, „Strong Tosa‟ moderadamente resistente, „Ojakkyo‟ e „Calabash TI-191‟ resistentes e o isolado Dbr 37 se mostrou mais agressivo dentre os isolados. No segundo experimento, o híbrido de meloeiro „Bônus II‟ foi enxertado nos porta-enxertos „Dinero‟ e „Strong Tosa‟, inoculadas com o isolado Dbr 37 do fungo e submetidas a diferentes concentrações de potássio (0; 62,5; 125; 187,5; 250 mg L-1), tanto plantas enxertadas como pé-franco. As plantas do híbrido „Bônus II‟ enxertadas foram resistentes ao fungo e as pé-franco susceptíveis. As concentrações de potássio não influenciaram no tamanho da lesão e na sobrevivência das plantas, porém influenciaram na condutância estomática e transpiração das plantas. / Abstract: Chemical control of the fungus Didymella bryoniae, causal agent of gummy stem blight of melon, is frequently inefficient. Alternative methods as grafting on resistant rootstocks and nutrition handling must be studied. Different rootstocks and potassium concentrations were tested to control the disease on net melon grown under plastic house conditions. In a first experiment four rootstocks (melon „Dinero‟, watermelon „Ojakkyo‟, squash „Strong Tosa‟ and calabash „TI-191‟) were tested for resistance inoculated by disks mycelium (7 mm diameter) with four isolates ( Dbr 34, Dbr 36, Dbr 37 and Dbr 39) of D. bryoniae in stem previously injured. Based on lesion size „Dinero‟ proved to be susceptible to the fungus, „Strong Tosa‟ moderately resistant and „Ojakkyo‟ and „TI-191‟ resistant and the isolated Dbr 37 proved more aggressive among isolates. In a second experiment hybrid net melon „Bonus II‟ was grafted on rootstocks „Dinero‟ and „Strong Tosa‟, inoculated with isolate Dbr 37 of the fungus and submitted to different potassium concentration (0; 62,5; 125; 187,5; 250 mg L-1), inoculated both grafted plants as non grafted. Grafted plants of „Bonus II‟ were resistant to the fungus and the non grafted ones susceptible. Potassium concentrations did not influenced size of the lesion on the stem and also in the plants survival, however influence on stomatal conductance and transpiration plants. / Orientador: Rumy Goto / Coorientador: Edson Luiz Furtado / Coorientador: Dirceu Maximino Fernandes / Banca: César Júnor Bueno / Banca: Haydée Siqueira Santos / Mestre

Characteristics of quantitative resistance in pea (Pisum sativum L.) to Erysiphe pisi DC, the pathogen causing powdery mildew, were investigated. Cultivars and seedlines of pea expressing quantitative resistance to E. pisi were identified and evaluated, by measuring the amounts of pathogen present on plant surfaces in field and glasshouse experiments. Disease severity on cv. Quantum was intermediate when compared with that on cv. Bolero (susceptible) and cv. Resal (resistant) in a field experiment. In glasshouse experiments, two groups of cultivars, one with a high degree of resistance and the other with nil to low degrees of resistance to E. pisi, were identified. This indicated either that a different mechanism of resistance applied in the two groups, or that there has been no previous selection for intermediate resistance. Several other cultivars expressing quantitative resistance were identified in a field experiment. Quantitative resistance in Quantum did not affect germination of E. pisi conidia, but reduced infection efficiency of conidia on this cultivar compared with cv. Pania (susceptible). Other epidemiological characteristics of quantitative resistance expression in Quantum relative to Pania were a 33% reduction in total conidium production and a 16% increase in time to maximum daily conidium production, both expressed on a colony area basis. In Bolero, the total conidium production was reduced relative to Pania, but the time to maximum spore production on a colony area basis was shorter. There were no differences between the cultivars in pathogen colony size or numbers of haustoria produced by the pathogen. Electron microscope studies suggested that haustoria in Quantum plants were smaller and less lobed than those in Pania plants and the surface area to volume ratios of the lobes and haustorial bodies were larger in Pania than in Quantum. The progress in time and spread in space of E. pisi was measured in field plots of cultivars Quantum, Pania and Bolero as disease severity (proportion of leaf area infected). Division of leaves (nodes) into three different age groups (young, medium, old) was necessary because of large variability in disease severity within plants. Disease severity on leaves at young nodes was less than 4% until the final assessment at 35 days after inoculation (dai). Exponential disease progress curves were fitted for leaves at medium nodes. Mean disease severity on medium nodes 12 dai was greatest (P<0.001) on Bolero and Pania (9.3 and 6.8% of leaf area infected respectively), and least on Quantum (1.6%). The mean disease relative growth rate was greatest (P<0.001) for Quantum, but was delayed compared to Pania and Bolero. Gompertz growth curves were fitted to disease progress data for leaves at old nodes. The asymptote was 78.2% of leaf area infected on Quantum, significantly lower (P<0.001) than on Bolero or Pania, which reached 100%. The point of inflection on Quantum occurred 22.8 dai, later (P<0.001) than on Pania (18.8 dai) and Bolero (18.3 dai), and the mean disease severity at the point of inflection was 28.8% for Quantum, less (P<0.00l) than on Pania (38.9%) or Bolero (38.5%). The average daily rates of increase in disease severity did not differ between the cultivars. Disease progress on Quantum was delayed compared with Pania and Bolero. Disease gradients from inoculum foci to 12 m were detected at early stages of the epidemic but the effects of background inoculum and the rate of disease progress were greater than the focus effect. Gradients flattened with time as the disease epidemic intensified, which was evident from the large isopathic rates (between 2.2 and 4.0 m d⁻¹) Some epidemiological variables expressed in controlled environments (low infection efficiency, low maximum daily spore production and long time to maximum spore production) that characterised quantitative resistance in Quantum were correlated with disease progress and spread in the field. These findings could be utilised in pea breeding programmes to identify parent lines from which quantitatively resistant progeny could be selected.