Dessecantes na produção e qualidade de sementes de soja [ Glycine max (L) Merrill]

• Ano de defesa: 2009
• Autor(a) principal: Evangelista, José Renato Emiliorelli
• Orientador(a): Oliveira, João Almir
• Banca de defesa: Vieira, Antônio Rodrigues, Rezende, Pedro Milanez de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: UNIVERSIDADE FEDERAL DE LAVRAS
• Programa de Pós-Graduação: DAG - Departamento de Agricultura
• País: BRASIL
• Palavras-chave em Português: Dessecantes; Qualidade; Soja; Semente; Tolerância à dessecação; Testes fisiológicos; Patógenos; Quality; Herbicidas; Physiological tests; Desiccation; Desiccation tolerance; Patogens; Maturation
• Área do conhecimento CNPq: CNPQ_NÃO_INFORMADO
• Link de acesso: https://repositorio.ufla.br/handle/1/4110

The ideal time to harvest soybean seeds is the closest to physiological maturity, when the dry matter, vigour and germination are high, but at this stage, the water content in the seeds is very high what makes impossible the operation of harvesting the seeds. Therefore, the use of desiccants that do not affect the yield, the germination and vigour of the seed and still allow the harvest antecipation in areas of seed production is a promising practice for the final quality of production. The drying has also as objective to reduce the imbalance of maturation, the interference of weeds, efficiency of harvesters and high quality in harvested product, and release areas sooner and less infested for cultural inheritance. This work aimed to study the physiological quality of soybean seeds harvested at different phenological stages and the ideal moment of harvesting and the effect of different desiccants products in the soybean crop. For this, seeds were collected at different points in the production field, when the water content was about 60%, 55%, 50%, 40%, 35%, 30% and 25%. The harvested pods were threshed manually and part of the seeds were subjected to germination, emergence and emergence speed index tests, and the other part was drought up to 12% of moisture in a forced air circulation dryer, which was set to 35 º C constant temperature for further evaluation. To evaluate the effect of the desiccants Gramoxone, Reglone and Finale, the spraying was done when the seeds water content were 60%, 55%, 50%, 40%, 35%, 30% and 25%. Seeds were harvested when the water content reduced to 18%, drying was carried out in shade and the threshing was manual. We evaluated the seed yield, retention in bolters, 1000 seeds weight, electrical conductivity, germination test, emergency en seedbed, accelerated aging, cold test and health. It was concluded that the highest values of germination and seed vigor were obtained when harvested with humidity below 40%. The soybean seeds become desiccation tolerant when they have around 40% of water content. Soybean seeds dried with moisture content above 40%, has their physiological quality harmed. Gramoxone do not affect productivity and physiological quality of soybean seeds when applied to dry fields, which seeds have water content below 45%. The Finale affect germination, vigor and grain yield, in addition provides lower bolters seeds. The use of desiccants influence the incidence of pathogens in seeds, especially the fungus Cercospora Kikuchi.