Qualidade de sementes de soja armazenadas e tratadas com produtos fitossanitários

Abstract

The storage is essential to guarantee the physiological quality of soybean seeds. Thus, research in this scope is essential to provide information for the productive sector, from the phytosanitary treatment process, conditions of the storage environment and even characteristics inherent to the genotypes, guaranteeing the adequate recommendation for the storage of these seeds. The water content is essential for maintaining seed quality and despite this, there are few recommendations for this factor in relation to the process of chemical treatment of soybean seeds. Another factor that has been observed in recent years is the occurrence of soybean cultivars with a greater amount of tegument tears, which are still little explored in quality control, mainly in relation to their influence on the quality of treated and stored seeds. Another important aspect concerns the differences between soybean seed cultivars in relation to storage tolerance, which despite being highly productive, present different responses in relation to quality during storage. Thus, three studies were carried out with the objectives of evaluating how the water content of soybean seeds at the time of chemical treatment affects the quality of seeds stored at different temperatures and establishing ideal values for this operation; to evaluate the influence of tegument tearing on soybean seed quality, as a function of seed treatment and storage; analyze and relate lignin content in the tegument, enzymatic expressions and morphoanatomical analyzes of soybean cultivar seeds with the maintenance of physiological quality and storage tolerance. The initial water content influences the quality of soybean seeds treated during the storage period, and in seeds stored with an initial water content above 13%, there is a greater loss of quality during storage. Seed treatment with water content below 9% favors the incidence of mechanical damage and optimize imbibition damage when immediately evaluated by the germination test. Chemical treatment of seeds with water content close to 11% is recommended, due to the reduction of mechanical damage and preservation of quality after treatment and storage. Storage at a temperature of 10°C provides better conservation of the physiological quality of soybean seeds treated for up to 135 days. Under temperature conditions of 20-30 and 30°C, seed deterioration is more pronounced, especially at 30°C. There are differences between the genotypes studied in relation to storage tolerance due to the different levels of tegument tearing. The physiological quality of soybean seeds is affected under storage conditions at a temperature of 20-30ºC, at 60 days, mainly in treated seeds where deterioration is more pronounced. The level of tearing in the tegument influences the quality of seeds, in lots with percentages above 20%, there is a greater reduction in quality after storage and when treated, this effect is enhanced. There is an effect of genotype on the tolerance of soybean seeds to long periods storage. In seeds with high physiological quality and tolerant to storage, there is less accumulation of hydrogen peroxide and less lipid peroxidation. Morphoanatomical analyzes can contribute to the evaluation of genotypes for high physiological quality and storage tolerance.