Qualidade fisiológica de sementes de milho-doce BR 400 (bt) em função do teor de água na colheita e da temperatura de secagem
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Data
2002-01-01
Autores
Guiscem, Josiane Marlle
Nakagawa, João [UNESP]
Zucareli, Claudemir [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Tecnologia de Sementes (ABRATES)
Resumo
O objetivo deste estudo foi avaliar a qualidade fisiológica das sementes de milho-doce em função do teor de água na colheita e da temperatura de secagem em espiga. O experimento foi instalado na área experimental da FCA/Unesp, Botucatu-SP. Utilizou-se a cultivar BR 400 (bt) 'Super doce'. O delineamento experimental empregado foi o de blocos ao acaso com seis repetições, constituindo os tratamentos as épocas de colheitas. As colheitas das espigas foram iniciadas após a maturidade fisiológica; após despalhadas e divididas em duas porções, as espigas foram submetidas a secagem em estufas com circulação forçada nas temperaturas de 30 e 40ºC. Foi utilizada uma testemunha com sementes secadas no campo com 10,1% de teor de água. Foram determinados os teores de água das sementes, inicial e após a secagem, de todas as colheitas. Após a secagem, as espigas foram debulhadas manualmente, as sementes acondicionadas em saco de papel e armazenadas em condições ambientais de laboratório. As avaliações da qualidade fisiológica das sementes (emergência de plântulas no campo, índice de velocidade de emergência, matéria seca de plântulas, germinação, vigor-primeira contagem do teste de germinação, envelhecimento acelerado, teste de frio, condutividade elétrica e teores de Ca, Mg, K e Na lixiviados na solução do teste de condutividade elétrica) foram realizadas antes e após seis meses de armazenamento. As sementes de milho-doce cultivar BR 400 (bt), com teor de água igual ou menor do que 35%, podem ser submetidas à secagem em espiga a temperatura de 30 ou 40ºC, sem perdas significativas em sua qualidade fisiológica.
The purpose of the present research was to study the physiological seed quality of sweet corn as a function of water content at harvest time and drying temperatures of the ears. Experiments were made in the Agriculture School of São Paulo State University located in Botucatu, São Paulo, Brazil. Ears of sweet corn cultivar, BR 400 Super Sweet (brittle), were harvested at different times, starting at physiological seed maturity and submitted to different drying temperatures (30 and 40ºC) in an air circulation chamber. Field dried seeds, with 10.1% of water content, were utilized as a control. After drying, ears were shelled and seeds were stored in paper bags under laboratory environmental conditions. Initial water content of seed before and after drying was determined. Physiological seed quality for each harvesting date and drying temperature were analyzed before storage and six months after. The following characteristics were utilized: seedling emergency, speed of seedling emergence, seedling dry matter content, germination, first germination count, accelerated ageing, cold test, electrical conductivity and Ca, Mg, K and Na lixiviated from seeds in the water of the conductivity test. Seeds of the cultivars BR 400 (bt) with water content of 35% or less may be submitted to drying temperatures of 30 or 40ºC without loose physiological quality.
The purpose of the present research was to study the physiological seed quality of sweet corn as a function of water content at harvest time and drying temperatures of the ears. Experiments were made in the Agriculture School of São Paulo State University located in Botucatu, São Paulo, Brazil. Ears of sweet corn cultivar, BR 400 Super Sweet (brittle), were harvested at different times, starting at physiological seed maturity and submitted to different drying temperatures (30 and 40ºC) in an air circulation chamber. Field dried seeds, with 10.1% of water content, were utilized as a control. After drying, ears were shelled and seeds were stored in paper bags under laboratory environmental conditions. Initial water content of seed before and after drying was determined. Physiological seed quality for each harvesting date and drying temperature were analyzed before storage and six months after. The following characteristics were utilized: seedling emergency, speed of seedling emergence, seedling dry matter content, germination, first germination count, accelerated ageing, cold test, electrical conductivity and Ca, Mg, K and Na lixiviated from seeds in the water of the conductivity test. Seeds of the cultivars BR 400 (bt) with water content of 35% or less may be submitted to drying temperatures of 30 or 40ºC without loose physiological quality.
Descrição
Palavras-chave
sementes, milho-doce, temperatura de secagem, retardamento da colheita, teor de água, seed, sweet corn, drying temperature, moisture content
Como citar
Revista Brasileira de Sementes. Associação Brasileira de Tecnologia de Sementes, v. 24, n. 1, p. 220-228, 2002.