Qualidade fisiológica de sementes e crescimento de plântulas de feijoeiro, em função de aplicações de paraquat em pré-colheita
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Data
2012-03-01
Autores
Kappes, Claudinei [UNESP]
Arf, Orivaldo [UNESP]
Ferreira, João Paulo [UNESP]
Portugal, José Roberto [UNESP]
Alcalde, Andrews Molnar [UNESP]
Arf, Marcelo Valentini [UNESP]
Vilela, Rafael Gonçalves [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Escola de Agronomia e Engenharia de Alimentos/UFG
Resumo
A qualidade fisiológica de sementes e o crescimento de plântulas de feijão são influenciados pelo ambiente de produção e por práticas de manejo, como a dessecação química, em pré-colheita. O presente trabalho objetivou avaliar a qualidade fisiológica de sementes e o crescimento de plântulas de feijão, após aplicações de paraquat, em diferentes épocas e doses, em pré-colheita. Utilizou-se delineamento de blocos ao acaso, em esquema fatorial 4x4 (épocas de aplicação x doses do herbicida), com quatro repetições. O paraquat foi aplicado aos 30, 35, 40 e 45 dias após o florescimento da cultura (DAF), nas doses de 0 g ha-1, 200 g ha-1, 400 g ha-1 e 600 g ha-1. Os resultados foram submetidos a análise de variância, sendo as épocas comparadas pelo teste Tukey e as doses por regressão. A germinação, o envelhecimento acelerado de sementes e o comprimento total de plântula não foram prejudicados, após as aplicações de paraquat em pré-colheita. Porém, a germinação, após o teste de frio, e o comprimento da parte aérea de plântula foram afetados pelas épocas de aplicações de paraquat, obtendo-se melhores resultados quando o dessecante foi aplicado aos 30 DAF. A condutividade elétrica de sementes diminuiu linearmente, à medida em que as doses de paraquat aumentaram, e resultado similar foi constatado, também, para o comprimento de raiz primária de plântula, com aplicação aos 30 DAF, e primeira contagem de germinação e índice de velocidade de germinação, com aplicação aos 45 DAF. A qualidade fisiológica de sementes e o crescimento de plântulas foram afetados pela aplicação de paraquat em pré-colheita.
The physiological quality of seeds and the growth of bean seedlings are influenced by the production environment and handling practices, such as the pre-harvest chemical desiccation. This study aimed to evaluate the physiological quality of seeds and growth of bean seedlings, after pre-harvest paraquat applications in different times and rates. A randomized blocks design, in a 4x4 (application time x herbicide rates) factorial scheme, was used, with four replications. The paraquat was applied at 30, 35, 40, and 45 days after flowering (DAF), in rates of 0 g ha-1, 200 g ha-1, 400 g ha-1, and 600 g ha-1. The results were submitted to variance analysis, the times compared by using the Tukey test and the rates by regression. The germination, accelerated aging of seeds, and total seedling length were not affected after the pre-harvest paraquat applications. However, the germination, after the cold test, and the seedling shoot length were affected by paraquat application times, presenting better results when the desiccant was applied at 30 DAF. The electrical conductivity of seeds decreased linearly in proportion to the increase of paraquat rates, and similar results were also observed for primary root length of seedling, with application at 30 DAF, and for first germination counting and germination speed index, with application at 45 DAF. The physiological quality of seeds and growth of seedlings were affected by pre-harvest paraquat application.
The physiological quality of seeds and the growth of bean seedlings are influenced by the production environment and handling practices, such as the pre-harvest chemical desiccation. This study aimed to evaluate the physiological quality of seeds and growth of bean seedlings, after pre-harvest paraquat applications in different times and rates. A randomized blocks design, in a 4x4 (application time x herbicide rates) factorial scheme, was used, with four replications. The paraquat was applied at 30, 35, 40, and 45 days after flowering (DAF), in rates of 0 g ha-1, 200 g ha-1, 400 g ha-1, and 600 g ha-1. The results were submitted to variance analysis, the times compared by using the Tukey test and the rates by regression. The germination, accelerated aging of seeds, and total seedling length were not affected after the pre-harvest paraquat applications. However, the germination, after the cold test, and the seedling shoot length were affected by paraquat application times, presenting better results when the desiccant was applied at 30 DAF. The electrical conductivity of seeds decreased linearly in proportion to the increase of paraquat rates, and similar results were also observed for primary root length of seedling, with application at 30 DAF, and for first germination counting and germination speed index, with application at 45 DAF. The physiological quality of seeds and growth of seedlings were affected by pre-harvest paraquat application.
Descrição
Palavras-chave
Phaseolus vulgaris L., dessecação com herbicida, germinação, vigor de sementes, Phaseolus vulgaris L., herbicidal desiccation, germination, seeds vigor
Como citar
Pesquisa Agropecuária Tropical. Escola de Agronomia e Engenharia de Alimentos/UFG, v. 42, n. 1, p. 9-18, 2012.