Paraquat action in reproductive phases of sunflower on agronomic behavior and seed quality

Abstract

The use of pre-harvest desiccants contributes to reducing the exposure of seeds to unfavorable climatic conditions, reducing environmental interference in their quality. But this use must be done in a way that affects, as little as possible, the agronomic behavior of the plants. The objective of this study was to evaluate the action of paraquat desiccation, applied at different reproductive stages, on the agronomic behavior of sunflower plants and the quality of its seeds. The experimental design used was randomized blocks in a factorial scheme with three repetitions. The herbicide Paraquat (2,0 L ha-1) was applied in the phases R7, R8 and R9 to plants of the cultivars BRS 323, Aguará 4 and M734. The characters evaluated were achene yield, oil content, weight of one thousand achenes, and germination. The most adequate reproductive stage for desiccation of sunflower plants with Paraquat was the R8 stage, obtaining the highest yield of achenes, oil content and weight of one thousand achenes. At this reproductive stage, there was no difference between the average germination values of sunflower achenes obtained with or without the application of the desiccant.