Testes de vigor e sanidade de sementes de Brachiaria brizantha cv. Marandú e Xaraés
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Data
2016-07-27
Autores
Melo, Paulo Alexandre Fernandes Rodrigues de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Dentro de um programa de controle de qualidade, a avaliação da sanidade e do vigor das sementes é necessária para o sucesso da produção. Assim, o trabalho foi conduzido com o objetivo de identificar os fungos e verificar a eficiência de testes de vigor na diferenciação da qualidade dos lotes de sementes de Brachiaria brizantha cv. Marandú e Xaraés, visando obter informações sobre a qualidade sanitária das sementes e a emergência de plântulas em campo. Vinte lotes de sementes produzidas nos Estados de Mato Grosso do Sul, Mato Grosso, Goiás, Minas Gerais, São Paulo e Bahia foram submetidos à avaliação do teor de água, germinação e microflora fúngica, realizada pelo método do papel de filtro (blotter-test). Para avaliar o vigor e potencial fisiológico foram utilizados dezessete lotes de sementes, sendo oito da cultivar Marandú e nove da Xaraés, avaliados quanto ao teor de água, testes de germinação e vigor (primeira contagem de germinação, condutividade elétrica, emergência de plântulas, primeira contagem e índice de velocidade de emergência de plântulas em areia no laboratório e emergência de plântulas em campo). A microflora fúngica diagnosticada em sementes comerciais de capim marandú e xaraés é constituída por Helminthosporium sp., Fusarium sp., Phoma sp., Curvularia sp., Pyricularia grisea, Chaetomium sp., Nigrospora sp., Colletotrichum sp. e Aspergillus sp. não afeta a germinação de sementes de capim-marandú, no entanto, a incidência de Fusarium sp. e Aspergillus sp. reduz a germinação de sementes de capim-xaraés. Em relação aos locais de produção, nenhum se destacou quanto à qualidade sanitária das sementes produzidas. Os fungos mais disseminados, que ocorreram em mais de 90% dos lotes das diversas regiões de procedência foram Helminthosporium sp. em sementes de capim-marandú, Chaetomium sp. em capim-xaraés e Fusarium sp. em sementes de ambos os capins. Este é o primeiro relato de ocorrência de Pyricularia grisea em sementes de gramíneas forrageiras tropicais produzidas no Sudeste (Monte Alegre de Minas - MG) e Nordeste (Luís Eduardo Magalhães - BA) do Brasil. O teste de condutividade elétrica utilizando o método alternativo de amostragem de sementes imersas em 75 mL de água e leituras após duas ou quatro horas de embebição, assim como, os testes de germinação, emergência de plântulas e o índice de velocidade de emergência de plântulas em areia são os mais sensíveis na diferenciação do vigor e potencial fisiológico dos lotes de sementes visando à emergência de plântulas em campo para sementes dos capins marandú e xaraés, respectivamente.
Within a quality control program, the evaluation of health and seeds vigor are fundamental and necessary for the successful production. Thus, this study was conducted in order to identify fungi and verify the efficiency of vigor tests in the quality differentiating of Brachiaria brizantha cv., Marandu and Xaraes seed lots, in order to obtain information that improve the sanitary quality of seeds and seedling emergence in the field. Twenty seed lots produced in the states of Mato Grosso do Sul, Mato Grosso, Goias, Minas Gerais, Sao Paulo and Bahia were evaluated for water content, germination and fungal microflora by the filter paper method (blotter-test). To evaluate the vigor and potential physiological were used seventeen seed lots, eight of the cultivar Marandu and nine of the Xaraes submitted to the germination test, first counting of germination test, electrical conductivity, seedling emergence, first germination count and seedling emergence speed index in the sand performed in the laboratory and emergency seedling tests in the field. The fungal microflora diagnosed in commercial seed lots of marandu and xaraes grasses consists of Helminthosporium sp., Fusarium sp., Phoma sp., Curvularia sp., Pyricularia grisea, Chaetomium sp., Nigrospora sp., Colletotrichum sp. and Aspergillus sp.. germination of marandu grass seeds was not affected by the incidence of fungi. The incidence of Fusarium sp. and Aspergillus sp reduces the germination of xaraes Regarding producing locations, none stands out as to sanitary quality of the seeds produced. The grass seeds. This is the first report of the occurrence of Pyricularia grisea in tropical grasses seed produced in Southeast (Monte Alegre de Minas - MG) and Northeast (Luis Eduardo Magalhaes - BA) of Brazil. Electrical conductivity test using the sampling alternative method of seeds immersed in 75 mL of water and readings after two or four hours, as well as germination tests, seedling emergence and seedling emergence speed index in the sand are efficient in the evaluation of the vigor and potential physiological of seed lots of marandu and xaraes grass aiming to the seedling emergence in field respectively.
Within a quality control program, the evaluation of health and seeds vigor are fundamental and necessary for the successful production. Thus, this study was conducted in order to identify fungi and verify the efficiency of vigor tests in the quality differentiating of Brachiaria brizantha cv., Marandu and Xaraes seed lots, in order to obtain information that improve the sanitary quality of seeds and seedling emergence in the field. Twenty seed lots produced in the states of Mato Grosso do Sul, Mato Grosso, Goias, Minas Gerais, Sao Paulo and Bahia were evaluated for water content, germination and fungal microflora by the filter paper method (blotter-test). To evaluate the vigor and potential physiological were used seventeen seed lots, eight of the cultivar Marandu and nine of the Xaraes submitted to the germination test, first counting of germination test, electrical conductivity, seedling emergence, first germination count and seedling emergence speed index in the sand performed in the laboratory and emergency seedling tests in the field. The fungal microflora diagnosed in commercial seed lots of marandu and xaraes grasses consists of Helminthosporium sp., Fusarium sp., Phoma sp., Curvularia sp., Pyricularia grisea, Chaetomium sp., Nigrospora sp., Colletotrichum sp. and Aspergillus sp.. germination of marandu grass seeds was not affected by the incidence of fungi. The incidence of Fusarium sp. and Aspergillus sp reduces the germination of xaraes Regarding producing locations, none stands out as to sanitary quality of the seeds produced. The grass seeds. This is the first report of the occurrence of Pyricularia grisea in tropical grasses seed produced in Southeast (Monte Alegre de Minas - MG) and Northeast (Luis Eduardo Magalhaes - BA) of Brazil. Electrical conductivity test using the sampling alternative method of seeds immersed in 75 mL of water and readings after two or four hours, as well as germination tests, seedling emergence and seedling emergence speed index in the sand are efficient in the evaluation of the vigor and potential physiological of seed lots of marandu and xaraes grass aiming to the seedling emergence in field respectively.
Descrição
Palavras-chave
Patologia de sementes, Potencial fisiológico, Sementes de forrageiras, Urochloa brizantha, Pathology seeds, Potential physiological, Forage seeds, Urochloa brizantha