Transmissão planta - semente de Curtobacterium flaccumfaciens pv. flacumfaciens em cultivares de feijoeiro
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Data
2008-10-17
Autores
Camara, Renata de Cássia [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
murcha-de-curtobacterium é uma doença que acarreta sérios prejuízos na produção do feijoeiro no País e seu agente causal, a bactéria Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), é transmitido por sementes. São indicados o uso de sementes livres do patógeno, rotação de culturas e cultivares resistentes para o manejo da doença em campo. Foi realizada a avaliação da transmissão de Cff via sementes de feijão, em três ensaios, em seis cultivares de feijoeiro (IAC Carioca, IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã, IAC Carioca Tybatã e Pérola). Essas cultivares foram inoculadas com um isolado de Cff via punção no caule e os sintomas da doença foram avaliados com uma escala de notas. A análise da transmissão da bactéria pelas sementes foi realizada nos três ensaios, em 500 sementes das cultivares IAC Carioca, IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã, IAC Carioca Tybatã e para a cultivar Pérola, foram analisadas 46, 155 e 87 sementes respectivamente no primeiro, segundo e terceiro ensaios. As sementes foram maceradas individualmente em água destilada e esterilizada, incubadas por 24 horas e a suspensão obtida foi semeada em placas de Petri contendo meio de cultura semi-seletivo para Cff e incubadas à temperarura de 28 a 30 oC, durante 96 a 120 horas. As colônias com características típicas de Cff, comparadas com um isolado puro padrão, foram purificadas em meio NSA + NaCl 7%, realizados testes de coloração diferencial de Gram, KOH e patogenicidade. Os isolados primeiro e segundo ensaios foram caracterizados por Microlog2TM e os do terceiro, via PCR. Os resultados mostraram que as cultivares de feijoeiro IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã e IAC Carioca Tybatã apresentaram baixos índices de severidade da doença, indicando resistência à murcha-de-curtobacterium, já as cultivares Pérola e IAC...
Bean bacterial wilt is a disease that cause serious losses to the Brazilian dry beans production and its causal agent, Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), is seedtransmitted. The use of pathogen-free seeds, culture rotation and resistant cultivars are recommended for disease handling on the field. The evaluation of Cff transmission by seeds was carried out by conducting three assays in six common beans cultivars (IAC Carioca, IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã, IAC Carioca Tybatã and Pérola). These cultivars were inoculated with a Cff isolate via a puncture on the stem and the desease symptoms were evaluated with severity index. The analysis of bacterial seed transmission was carried out in all of the three assays in 500 seeds of cultivars IAC Carioca, IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã and IAC Carioca Tybatã. For cultivar Pérola, 46; 155 and 87 seeds were analyzed respectively on the first, second and third assays. Seeds were individually macerated in distilled and sterilized water for 24 hours and the suspension thus obtained was sown on Petri dishes with a Cff semi-selective medium and incubated at 28 - 30 °C from 96 to 120 h. Colonies with typical Cff characteristics as compared with a standard pure isolate were purified in a NSA + NaCl 7% medium, Gram, KOH and pathogenicity tests being carried out. The isolates from the first and second assays were characterized by Microlog2TM and those of the third one by PCR. Results showed that common beans cultivars IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã and IAC Carioca Tybatã presented... (Complete abstract click electronic access below)
Bean bacterial wilt is a disease that cause serious losses to the Brazilian dry beans production and its causal agent, Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), is seedtransmitted. The use of pathogen-free seeds, culture rotation and resistant cultivars are recommended for disease handling on the field. The evaluation of Cff transmission by seeds was carried out by conducting three assays in six common beans cultivars (IAC Carioca, IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã, IAC Carioca Tybatã and Pérola). These cultivars were inoculated with a Cff isolate via a puncture on the stem and the desease symptoms were evaluated with severity index. The analysis of bacterial seed transmission was carried out in all of the three assays in 500 seeds of cultivars IAC Carioca, IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã and IAC Carioca Tybatã. For cultivar Pérola, 46; 155 and 87 seeds were analyzed respectively on the first, second and third assays. Seeds were individually macerated in distilled and sterilized water for 24 hours and the suspension thus obtained was sown on Petri dishes with a Cff semi-selective medium and incubated at 28 - 30 °C from 96 to 120 h. Colonies with typical Cff characteristics as compared with a standard pure isolate were purified in a NSA + NaCl 7% medium, Gram, KOH and pathogenicity tests being carried out. The isolates from the first and second assays were characterized by Microlog2TM and those of the third one by PCR. Results showed that common beans cultivars IAC Carioca Aruã, IAC Carioca Akytã, IAC Carioca Pyatã and IAC Carioca Tybatã presented... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Feijão comum, Fitopatologia, Feijão comum - Resistencia a doenças e pragas, Murcha-de-curtobacterium, Phaseolus vulgaris, Resistance, Wilt
Como citar
CAMARA, Renata de Cássia. Transmissão planta - semente de Curtobacterium flaccumfaciens pv. flacumfaciens em cultivares de feijoeiro. 2008. v, 41 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas de Botucatu, 2008.