Duração do teste de germinação de Brachiaria brizantha cv. Marandu (Hochst. ex A. Rich ) Stapf
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Data
2005-02-01
Autores
Gaspar, Carolina Maria [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O tempo recomendado pelas Regras para Análise de Sementes (R.A.S.), para a conclusão do teste de germinação de Brachiaria brizantha, é considerado longo pelos laboratórios de análise, produtores e comerciantes dessas sementes, representando um entrave na tomada de decisões relacionadas à comercialização. O presente trabalho objetivou determinar o tempo mínimo necessário à realização do teste de germinação para sementes de B. brizantha cv. Marandu (Hochst. ex A. Rich.) Stapf e determinar o método de superação de dormência e a temperatura, recomendados pelas R.A.S., que proporcionem a maior germinação no menor tempo. A pesquisa foi conduzida em duas etapas. Na primeira, trinta lotes de sementes foram submetidos ao teste de germinação, com quatro repetições, sob duas condições de temperaturas alternadas (15-35ºC e 20-35ºC), sem (ausente) e com os seguintes métodos para a superação de dormência: umedecimento do substrato com KNO3 (0,2%) e imersão das sementes em H2SO4 (98% 36N) por 15 minutos, seguido de lavagem em água, constituindo 6 tratamentos. Realizaram-se contagens diárias do número de plântulas normais, para a determinação da data mais apropriada para o término do teste. Na segunda etapa foram realizados testes de germinação em oito lotes, sendo dois de alto vigor, quatro de médio vigor e dois de baixo vigor, nos mesmos 6 tratamentos e com encerramento nas datas definidas na primeira etapa da pesquisa. As sementes não germinadas após o término do teste de germinação foram submetidas ao teste de tetrazólio para verificar sua vitalidade, e, dessa forma, comprovar a eficiência da metodologia estabelecida na primeira etapa. O delineamento experimental considerou os lotes como repetições. Na primeira etapa para cada repetição, em cada combinação de tratamento, foi realizado um ajuste...
The time recommended by the Brazilian Rules for Seed Analysis (R.A.S.) for the ending of the Brachiaria brizantha germination test, is considered long for the analysis laboratories, producers and merchants of those seeds, representing a problem in taking decisions related to commercialization. The present work had as objective to define the minimum time necessary to carry out the B. brizantha cv. Marandu (Hochst. ex. A. Rich.) Stapf. germination test and determine the dormancy breaking method and the temperature, recommended by R.A.S, that provide the largest germination in the smallest period. The research was carried out in two parts. In the first, 30 lots of seeds were submitted to the germination test, with four replicates, under two conditions of alternated temperatures (15-35ºC and 20-35ºC), without (none) and with the following dormancy breaking methods: substrate moistened with a solution of KNO3 (0,2%) and immersion of the seeds in H2SO4 (98% 36N) for 15 minutes, followed by a wash in water, forming 6 treatments. Daily counting of the number of normal seedlings was carried out, to define the most adequate date to the end of the test. In the second part germination tests were carried out in eight lots, being two of high vigor, four of medium vigor and two of low vigor, in the same 6 treatments and with the ending in date indicated in the first part of the experiment. The remaining seeds at the end of the germination test were submitted to the tetrazolium test to verify their viability, and, thus, confirm the efficiency of the methodology defined in the first part. The experimental design considered the lots as replicates. In the first part for each replicate, in each treatment combination, a non-linear adjustment was accomplished, in which the function parameters were estimated, and a growth curve to determine the minimum time necessary to carry out... (Complete abstract, click electronic access below)
The time recommended by the Brazilian Rules for Seed Analysis (R.A.S.) for the ending of the Brachiaria brizantha germination test, is considered long for the analysis laboratories, producers and merchants of those seeds, representing a problem in taking decisions related to commercialization. The present work had as objective to define the minimum time necessary to carry out the B. brizantha cv. Marandu (Hochst. ex. A. Rich.) Stapf. germination test and determine the dormancy breaking method and the temperature, recommended by R.A.S, that provide the largest germination in the smallest period. The research was carried out in two parts. In the first, 30 lots of seeds were submitted to the germination test, with four replicates, under two conditions of alternated temperatures (15-35ºC and 20-35ºC), without (none) and with the following dormancy breaking methods: substrate moistened with a solution of KNO3 (0,2%) and immersion of the seeds in H2SO4 (98% 36N) for 15 minutes, followed by a wash in water, forming 6 treatments. Daily counting of the number of normal seedlings was carried out, to define the most adequate date to the end of the test. In the second part germination tests were carried out in eight lots, being two of high vigor, four of medium vigor and two of low vigor, in the same 6 treatments and with the ending in date indicated in the first part of the experiment. The remaining seeds at the end of the germination test were submitted to the tetrazolium test to verify their viability, and, thus, confirm the efficiency of the methodology defined in the first part. The experimental design considered the lots as replicates. In the first part for each replicate, in each treatment combination, a non-linear adjustment was accomplished, in which the function parameters were estimated, and a growth curve to determine the minimum time necessary to carry out... (Complete abstract, click electronic access below)
Descrição
Palavras-chave
Capim-braquiaria, Brachiaria brizantha cv Marandu, Germinação, Sementes, Dormancy in plants, Seeds, Seeds - Longevity
Como citar
GASPAR, Carolina Maria. Duração do teste de germinação de Brachiaria brizantha cv. Marandu (Hochst. ex A. Rich ) Stapf. 2005. viii, 47 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2005.