Efeito de Colletotrichum dematium var. truncata e Cercospora kikuchii na germinação de sementes de soja
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Data
2005-12-01
Autores
Galli, Juliana Altafin [UNESP]
Panizzi, Rita de Cássia [UNESP]
Fessel, Simone Aparecida [UNESP]
Simoni, Fabiana de [UNESP]
Ito, Margarida Fumiko
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Tecnologia de Sementes (ABRATES)
Resumo
A antracnose, causada por Colletotrichum dematium var. truncata, é a principal doença da soja que afeta a fase inicial de formação das vagens, podendo causar a morte das plântulas. Cercospora kikuchii é o fungo causador da doença mancha púrpura nas sementes de soja, responsável por severas reduções no rendimento e na qualidade das sementes. O objetivo deste trabalho foi determinar o tempo mais apropriado para infecção das sementes de soja por C. dematium var. truncata e C. kikuchii, para posterior avaliação dos danos causados pelo fungo na germinação. Tais fungos foram cultivados em meio BDA. As sementes de soja cultivar MSOY 6101 foram colocadas sobre meio contendo o patógeno C. dematium var. truncata por 0 (testemunha), 4, 16, 24, 32 e 40h. As sementes da cv. CD 208 foram inoculadas com C. kikuchii pelos mesmos períodos citados, com adição de 48 e 56h. Após os respectivos tempos de contato, as sementes foram submetidas ao teste de sanidade (papel de filtro), com duas variações, sem e com assepsia superficial (hipoclorito de sódio 1% por três minutos). Determinado o tempo mais adequado de infecção, outras sementes foram infectadas pelo patógeno e, posteriormente, foram realizados testes de germinação em papel e areia com uma mistura de sementes sadias (colocadas sobre o meio BDA) e sementes inoculadas, resultando em lotes com 0, 20, 40, 60, 80 e 100% de sementes infectadas. O tempo de incubação de 40 e 56 horas para C. dematium var truncata e C. Kikuchii, respectivamente são suficientes para obtenção da totalidade das sementes infectadas. C. Kikuchii não prejudica a germinação das sementes.
Anthracnose, caused by Colletotrichum dematium var. truncata, is the main soybean disease that affects soybean yields. Cercospora kikuchii is the fungus that causes the purple stain disease in soybean seeds that causes severe reductions in the yield and quality of the seeds. The objective of this study was to determine the optimum period of contact of the soybean seeds with C. dematium var. truncata and C. kikuchii, for subsequent evaluation of the damage caused by the fungus on seed germination. The fungus was cultivated in PDA medium. The soybean seeds cv. MSOY 6101 were placed on Petri dishes with culture media colonized by C. dematium var. truncata for 0 (control), 4, 16, 24, 32 and 40h. The seeds of the cv. CD 208 were inoculated with C. kikuchii for the same mentioned periods, with the addition of 48 and 56h. After the respective periods of contact, they were submitted to the Blotter test, with and without superficial asepsis (sodium hipoclorite 1%, 3 minutes). After determining the optimum incubation period, other seeds were infected with the pathogen and, later, germination tests were accomplished in paper and in sand with a mixture of healthy seeds (placed on PDA medium) and inoculated seeds, resulting in lots with 0, 20, 40, 60, 80 and 100% infected seeds. The incubation time of C. dematium var truncata and C. Kikuchii, was 40 and 56 hours, respectively, and was sufficient to obtain completely infected seeds. C. Kikuchii not reduce seed germination.
Anthracnose, caused by Colletotrichum dematium var. truncata, is the main soybean disease that affects soybean yields. Cercospora kikuchii is the fungus that causes the purple stain disease in soybean seeds that causes severe reductions in the yield and quality of the seeds. The objective of this study was to determine the optimum period of contact of the soybean seeds with C. dematium var. truncata and C. kikuchii, for subsequent evaluation of the damage caused by the fungus on seed germination. The fungus was cultivated in PDA medium. The soybean seeds cv. MSOY 6101 were placed on Petri dishes with culture media colonized by C. dematium var. truncata for 0 (control), 4, 16, 24, 32 and 40h. The seeds of the cv. CD 208 were inoculated with C. kikuchii for the same mentioned periods, with the addition of 48 and 56h. After the respective periods of contact, they were submitted to the Blotter test, with and without superficial asepsis (sodium hipoclorite 1%, 3 minutes). After determining the optimum incubation period, other seeds were infected with the pathogen and, later, germination tests were accomplished in paper and in sand with a mixture of healthy seeds (placed on PDA medium) and inoculated seeds, resulting in lots with 0, 20, 40, 60, 80 and 100% infected seeds. The incubation time of C. dematium var truncata and C. Kikuchii, was 40 and 56 hours, respectively, and was sufficient to obtain completely infected seeds. C. Kikuchii not reduce seed germination.
Descrição
Palavras-chave
Anthracnose, stain purple, seed pathology, Antracnose, mancha púrpura, Patologia de sementes
Como citar
Revista Brasileira de Sementes. Associação Brasileira de Tecnologia de Sementes, v. 27, n. 2, p. 182-187, 2005.