Characterization of acquisition of physiological quality in soybean seeds from desiccated plants

ABSTRACT: Desiccation interrupts the acquisition of physiological quality in soybean seeds, as this quality peaks at R9. However, this interruption can be mitigated by the stage in which herbicide is applied and which herbicide is used. The aim of this study was to characterize the acquisition of physiological quality in soybean seeds from plants desiccated by herbicides at different stages. A completely randomized experimental design was used in a 3×6 factorial arrangement, consisting of three phenological stages (R6, R7.1, R7.3) and six different desiccant treatments (Diquat 1.5 L.ha-1; Glufosinate 1.5 L.ha-1 and 2.0 L.ha-1; Diquat 1.0 L.ha-1 + Glufosinate 1.0 L.ha-1; Saflufenacil 140 g.ha1 + Glufosinate 1.0 L.ha-1; and Saflufenacil 140 g.ha-1 + Diquat 1.0 L.ha-1), with four replications. The following evaluations were made: desiccation rate, germination, desiccation tolerance (DT), longevity (P50), viability after one year of storage, and thousand seed weight. Seeds are able to germinate and have DT when plant desiccation through application of Diquat, Diquat + Glufosinate, Saflufenacil + Diquat, and Saflufenacil + Glufosinate occurs at R6, and for Glufosinate, at R7.1. The use of Diquat + Glufosinate and their combination with Saflufenacil showed less impact on acquisition of soybean seed longevity, which was better when application was made at R7.3.