Alterações fisiológicas nos componentes de rendimento e qualidade nutricional do gergelim associadas a aplicação de dessecante

• Ano de defesa: 2022
• Autor(a) principal: Lopes, Maria de Fátima de Queiroz
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Agropecuária; Programa de Pós-Graduação em Agronomia; UFPB
• Palavras-chave em Português: colheita; fotossíntese; minerais; potencial produtivo; Sesamum indicum; vigor; CNPQ::CIENCIAS AGRARIAS
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/123456789/29671

Sesame (Sesamum indicum) is considered one of the most important oilseed species in the world. Despite the importance, the non-uniformity in the maturation of the crop causes difficulty for its expansion and losses in the harvest, in this sense, herbicides appear as an alternative for desiccation and optimization in the harvesting process. With this, the objective of the research was to evaluate the potential of desiccants from the identification of the type and time of application of the product in the culture, as well as the harvest period in different parts of the plant, in order to evaluate their effects on the physiology of the plant. plant and its seeds, production components and nutritional quality of seeds from two stages of maturation. For this, the cultivar BRS Anahí was cultivated under rainfed conditions for two years, applying glyphosate and diuron + paraquat as desiccants in pre-harvest, in two reproductive periods (R5 and R7), with different forms of application (conventional spraying, directed jet, control) using a randomized block design. Gas exchange, photochemical efficiency, chlorophyll a, b and total, phytotoxicity, production components, physiological seed quality, proximate composition and mineral content were evaluated. Data were subjected to multivariate analysis of clustering, principal components and correlation. Among the products used, glyphosate caused less interference on the physiology of the plant and provided a greater production of the culture and there were no expressive changes in the centesimal and mineral composition in relation to the control, promoting improvements in the uniformity of desiccation of the plant, on the other hand. On the other hand, both products impair the physiological quality of the seeds, and glyphosate is responsible for promoting greater phytotoxicity to the root system of sesame seedlings. The jet directed, for both products, at the base of the plant promotes less phytotoxicity and is more efficient in production by avoiding the opening of the capsules and seed release, and mainly by facilitating the mechanized harvest of the culture and guaranteeing good physiological potential of the seeds, in contrast, the conventional application. reduces the productivity and speed of germination and emergence of seedlings. The application in R7 is more efficient and does not interfere with the production and physiological quality and nutritional composition of the seed. The late harvest stands out in relation to the early harvest and the lower part of the plant presents more favorable results in relation to the physiological quality and proximate composition of the seeds, while the upper part has a higher mineral content. Thus, with regard to late harvest (90-105 days) for grain production, the application of glyphosate in the R7 phase, with the directed jet, does not change the centesimal and mineral composition of sesame seeds. In conclusion, for grain production, desiccation with glyphosate in the R7 phase, applied with the directed jet and late harvest is recommended, as it does not change the proximate and mineral composition of sesame seeds.