Burndown herbicides in Crambe abyssinica crops: seed yield and quality

Abstract

The application of burndown herbicides to crambe crops is important for production of quality seeds. The objective of this work was to evaluate the effect of burndown herbicides applied at pre-harvest, using different spray volumes, on seed yield and quality of crambe plants (Crambe abyssinica cv. FMS Brilhante). A randomized block experimental design was used, with four replications, in a 2×5 factorial arrangement consisted of two burndown herbicides [glyphosate (Roundup Original 360 g L^-1) and diquat (Reglone 200 g L^-1)] and five spray volumes (0.0, 0.5, 1.0, 1.5, and 2.0 L ha^-1). The burndown herbicides were applied at 74 days after sowing, when the plants presented 80% brown seeds, based on visual evaluation of the seed maturation stage. After harvest, the seeds were processed and evaluated for water content, one-thousand seed weight, seed yield, oil contents, germination, and vigor (first germination counting, emergence speed index, accelerated aging, and electrical conductivity). The pre-harvest desiccation of crambe with the herbicide diquat, using spray volumes between 1.3 and 1.5 L ha^-1, resulted in seeds with better physiological quality. The seed vigor was low when using desiccation of plants with glyphosate. The crop yield was not affected by the herbicides nor by the different spray volumes.