Aplicação estratificada do tratamento químico na manutenção da qualidade fisiológica de sementes de milho armazenadas

Abstract

The increasing adoption of industrial seed treatment and the need to anticipate this process for logistical reasons have extended the storage period of treated seeds. Maize seeds may be produced by the seed industry in the first season of an agricultural year and sown in the field, for grain production, in the second season of the following year. Thus, they can be subjected to prolonged storage periods, which can reach up to approximately 360 days. However, the prolonged storage of treated seeds may cause a loss of physiological quality due to the long exposure of the seeds to chemical treatment components with phytotoxic potential, especially insecticides from the neonicotinoid group. Therefore, recent studies have explored alternatives to solve or mitigate this negative effect, such as the stratified application of the chemical treatment, which consists of applying the products sequentially rather than simultaneously, under the hypothesis that this separation reduces the contact of the seeds with potentially phytotoxic products. In this context, the objective of this study was to evaluate the effectiveness of the stratified application of chemical treatment in maintaining the physiological quality of maize seeds. The experiment was conducted in a completely randomized design in a 2 × 2 × 5 triple factorial scheme, comparing stratified and conventional applications (the latter with all products applied simultaneously), using two chemical treatment formulations with insecticides from different chemical groups, and evaluations performed over one year of storage. Seed physiological quality was assessed through germination tests, radicle length, accelerated aging on substrate, and cold test. It is concluded that stratified application constitutes an efficient technological alternative to extend the storability of treated maize seeds by presenting significantly higher vigor values with formulations of high phytotoxic potential and prolonged storage, contributing to greater safety in early treatment and the maintenance of seed vigor until sowing.