Productivity and physiological quality of seeds with burn down herbicides at the pre harvest of bean crops

Abstract

The physiological quality of bean seeds is influenced by the production environment and management practices employed during cultivation. The objective of this study was to evaluate the productivity and physiological quality of bean seeds after desiccant applications at different times at pre-harvest. A randomized block design was used, with a factorial (3x3) + 1 arrangement, where the application of three desiccants was tested: glyphosate (960 g a.i. ha-1), paraquat dichloride (240 g a.i. ha-1) and glufosinate ammonium (400 g a.i. ha-1) + mineral oil, applied three times (days after flowering - DAF), and a control without herbicide in four replications. Seed quality was determined by the following tests: germination, first count, seedling emergence speed rate, accelerated aging, electrical conductivity and seedling dry biomass. Seed yield was not influenced by either herbicides or time of application. Regardless of time of application, the lowest percentage of normal seedlings after the germination, first count and accelerated aging tests was observed in seeds desiccated with the herbicide glufosinate ammonium. The herbicide glyphosate reduces seedling vigor. The times of application of the product paraquat dichloride did not affect the germination and vigor of bean seeds.