Qualidade fisiológica de sementes de crambe dessecado em pré-colheita com glyphosate

Abstract

Non-uniform seed maturation is a characteristic in some plant species, making it difficult to harvest at the right time. Thus, the application of desiccants in the pre-harvest can be an alternative, as it promotes the uniformity in the stand, reducing the period of permanence of the seeds in the field after the physiological maturity. The objective of this work was to evaluate the effect of desiccant glyphosate on the physiological quality of crambe seeds at different times of desiccation of preharvest plants. The experimental design was completely randomized in a 2 x 4 factorial scheme, involving the application of glyphosate desiccant in the preharvest plants and the control treatment (without plant desiccation), in four desiccation times, with three replications per treatment. The times of desiccation were based on the stages of seed maturation, verified by visual observation of the percentage of brown seeds (45, 60, 75 and 90%), which occurred at 88, 93, 98 and 103 days after sowing (DAS). The seeds were evaluated for water content, germination and vigor (first germination count, germination speed index, seedling emergence, fresh and dry matter of seedlings, accelerated aging and electrical conductivity). The desiccation of pre-harvest crambe plants with glyphosate positively affects the physiological quality of the seeds. When 90% of seed become brown color, which occurred at 103 days after sowing, the application of the desiccant in crambe plants provides seeds with higher physiological quality.