Dessecação Pré-Colheita de soja e performance fisiológica de sementes no armazenamento

Abstract

The uneven senescence between soybean plants is one of the major challenges for high quality seed production. Therefore, this study aims to evaluate the physiological quality of soybean seeds subjected to pre harvest desiccation while also evaluating the effect on quality during storage. Desiccation was performed at the R7.3 stage, using cultivars BMX Ativa RR and NA 5909 RG and the herbicides glufosinate-ammonium and diquat. These seeds were evaluated for germination, field emergence, accelerated aging and electrical conductivity, immediately after harvest and after three months of storage. When subjected to the germination test, quality of seeds from diquat and glufosinate-ammonium desiccated plants did not differ among storage times, while seeds from plants treated wit glufosinateammonium presented a better performance than Diquat in both periods. On the accelerated aging test, the cultivar BMX Ativa RR presented a better performance compared to NA 5909 RG in both periods tested and the two cultivars were superior before storage, still, for the cultivar NA 5909 RG the use of Diquat presented inferior performance when compared to glufosinate-ammonium and the control, while there was no difference between treatments used for the cultivar BMX Ativa RR. For field emergence evaluations at the 7 and 14 days, the use of the desiccant glufosinateammonium was superior in both evaluations for the cultivar NA 5909 RG, while for the cultivar BMX Ativa RR the use of diquat was superior in both evaluations. The results from the electrical conductivity tests indicated that the use of diquat and glufosinate-ammonium do not differ in the evaluations performed shortly after harvest, however, with greater amount of leached solutes than the control. Furthermore, when examined separately, in the evaluations performed after three months of storage, the use of glufosinate-ammonium presented a greater amount of leached solutes, followed by the use of diquat and, with lesser amounts of leached solutes, the control. The cultivar BMX Ativa RR presented smaller amounts of leached solutes when compared to the cultivar NA 5909 RG after desiccation with diquat and glufosinate-ammonium.