Antracnose em feijão-fava: caracterização do agente causal e reação de genótipos a Colletotrichum truncatum
Carregando...
Data
2009-09-24
Autores
Carvalho, Eulália Maria Sousa [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A antracnose é freqüentemente encontrada em feijão-fava na região nordeste do Brasil, porém é pouco estudada. Nesse sentido, objetivou-se caracterizar o agente causal da antracnose, determinar a reação de genótipos a Colletotrichum truncatum e investigar a viabilidade da utilização da técnica de folhas destacadas em estudos relacionados a essa doença. Isolados foram caracterizados em relação a aspectos morfoculturais quando cultivados em meios de cultura batata-dextrose-ágar (BDA) e feijão-dextrose-ágar (FDA), em temperaturas de 26, 28 e 30ºC e fotoperíodo de 12 horas. A patogenicidade dos isolados e a reação dos genótipos foram avaliadas em folhas destacadas e na planta. O comportamento dos genótipos foi avaliado em duas épocas, no período chuvoso (17 de abril a 02 de junho/2008) e período seco (13 de junho a 29 de julho/2008). O delineamento utilizado foi o inteiramente casualizado com cinco e quatro repetições para avaliação da patogenicidade e dos genótipos, respectivamente. As características morfológicas e culturais variaram de acordo com o isolado e condições de cultivo, porém, foram compatíveis com as descritas para a espécie C. truncatum. A patogenicidade foi comprovada, porém não foram detectadas diferenças significativas entre os isolados. Os primeiros sintomas da doença apareceram aos três dias após a inoculação em folhas destacadas e plantas. Os genótipos UFPI - 578, UFPI - 468 e UFPI - 26 foram suscetíveis a C. truncatum. Quando avaliados em folha destacada não diferiram estatisticamente entre si no nível de infecção, independente da época. Em planta e na ausência de chuva, UFPI - 26 apresentou o maior nível de infecção, enquanto UFPI - 578, o menor. A correlação positiva e significativa (P<0,0001) entre folha destacada e planta comprova a viabilidade do emprego da técnica de folhas destacadas em estudos relacionados a essa doença
Anthracnose is often found in lima bean plantations in the northeast region of Brazil, however, has been little studied. In this sense, the goals were to characterize the causal agent of anthracnose, determine the reaction of genotypes to Colletotrichum truncatum and investigate the viability of using the technique of detached leaves in studies related to this disease. Isolates were characterized in relation to aspects morphocultural when grown in culture BDA and FDA, in temperatures of 26, 28 and 30ºC and photoperiod of 12 hours. The pathogenicity of the isolates and the reaction of the genotypes were evaluated in detached leaf and plant. The behavior of the genotypes were evaluated in two seasons, in the presence and absence of rain. The design was completely randomized to five and four replicates to evaluate the pathogenicity and genotypes, respectively. The cultural and morphological characteristics varied according with the isolates and conditions of the grown, but were compatible with those described for the species C. truncatum. The pathogenicity was proved no significant differences between the isolates. The first symptoms of the disease appeared to three days after inoculation in detached leaves and plants. The genotypes UFPI - 578, UFPI - 468 and UFPI - 26 were susceptible to C. truncatum. When evaluated in detached leaves did not differ significantly among themselves in the level of infection, independent of the season. In plants, UFPI - 26 was the most susceptible in season 2 with the highest level of infection, while the UFPI - 578 was the least susceptible. The positive and significant correlation (P <0.0001) between detached leaves and plant prove the viability of employment of detached leaves in studies related to this disease
Anthracnose is often found in lima bean plantations in the northeast region of Brazil, however, has been little studied. In this sense, the goals were to characterize the causal agent of anthracnose, determine the reaction of genotypes to Colletotrichum truncatum and investigate the viability of using the technique of detached leaves in studies related to this disease. Isolates were characterized in relation to aspects morphocultural when grown in culture BDA and FDA, in temperatures of 26, 28 and 30ºC and photoperiod of 12 hours. The pathogenicity of the isolates and the reaction of the genotypes were evaluated in detached leaf and plant. The behavior of the genotypes were evaluated in two seasons, in the presence and absence of rain. The design was completely randomized to five and four replicates to evaluate the pathogenicity and genotypes, respectively. The cultural and morphological characteristics varied according with the isolates and conditions of the grown, but were compatible with those described for the species C. truncatum. The pathogenicity was proved no significant differences between the isolates. The first symptoms of the disease appeared to three days after inoculation in detached leaves and plants. The genotypes UFPI - 578, UFPI - 468 and UFPI - 26 were susceptible to C. truncatum. When evaluated in detached leaves did not differ significantly among themselves in the level of infection, independent of the season. In plants, UFPI - 26 was the most susceptible in season 2 with the highest level of infection, while the UFPI - 578 was the least susceptible. The positive and significant correlation (P <0.0001) between detached leaves and plant prove the viability of employment of detached leaves in studies related to this disease
Descrição
Palavras-chave
Vagem, Patogenicidade, Antracnose, Phaseolus lunatus, Appressoria, Detached leaf, Pathogenicity
Como citar
CARVALHO, Eulália Maria Sousa. Antracnose em feijão-fava: caracterização do agente causal e reação de genótipos a Colletotrichum truncatum. 2009. xiv, 53 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2009.