Dessecação em pré-colheita e armazenamento na qualidade de sementes de crambe

Abstract

The use of desiccants constitutes a technique to standardize seed maturation, allowing the anticipation of the harvest and avoiding its exposure to unfavorable environmental conditions in the field, with reflexes on the physiological quality, which can be influenced by the time and condition of storage. Thus, the objective was to evaluate the effects of using desiccant herbicides applied in pre-harvest and storage on the physiological quality of crambe seeds. For this, two experiments were conducted in a randomized block design, with four replications per treatment. In the first experiment, the treatments were arranged in a 2 x 5 factorial arrangement, involving the pre-harvest application of two desiccant herbicides (Diquat and Glyphosate) and five dosages (0.0; 0.5; 1.0; 1.5 and 2.0 L ha-1 ). After harvesting and processing, the seeds were subjected to evaluations of water content, weight of a thousand seeds, productivity, oil content, germination and vigor (first germination count, emergence speed index, accelerated aging and electrical conductivity). The second experiment was conducted in a 2 x 2 x 5 factorial arrangement, which consisted of harvesting seeds obtained from plants with and without desiccation, two types of packaging (paper bags and polyethylene bags) and five storage times (0, 3 , 6, 9 and 12 months). The analyzes consisted of determining the water content of the seeds and evaluating their physiological quality by means of germination tests, seedling emergence, emergence speed index, accelerated aging and electrical conductivity. Productivity and germination were not influenced by desiccants and their dosages. However, the vigor of the seeds, evaluated by the tests of accelerated aging and electrical conductivity, was negatively affected by the herbicide Glyphosate, whereas seeds obtained from plants dried with Diquat, in dosages between 1.3 to 1.5 L ha-1 showed higher physiological quality. In addition, the physiological performance of the seeds was enhanced by storage in ambient conditions for nine months, whose paper packaging provided a better condition for preserving their vigor.