Seed vigor is a multiple and complex trait associated with various aspects of seed performance, such as rate and uniformity of germination and tolerance to adverse conditions. The metabolic events activated in early imbibition may provide important information to explain behavior variations in seeds with different vigor levels. The objective was to study soybean seed vigor using different approaches. For this experiment, soybean seeds of cultivars BRS 133 and MG/BR 46 (Conquista) were produced under ideal conditions and under drought stress (from R5.5). In chapter 1, the seeds were submitted to physiological quality tests, biochemical analyzes, biospeckle activity during imbibition and expression of genes related to vigor evaluated in the embryonic axis at 0, 6 and 10 hours after imbibition. In chapter 2, the objective was to study two hydropriming protocols (soaking in water and between paper) and to evaluate the effects on the physiological performance and gene expression of soybean seeds produced in chapter 1. In chapter 1, the results indicated that the drought stress during seed development and maturation not only reduces the vigor of the soybean seeds produced, but also changes the levels of enzymatic activity, biospeckle activity and gene expression during imbibition. During early imbibition, there are significant changes in the gene expression of genes related to several processes, such as DNA repair, oxidative stress, respiratory activities, cell elongation and cell wall modification. In chapter 2, the hydropriming between paper provided higher percentage and speed of germination, and faster onset of the protrusion, especially in suboptimal temperatures. Gene expression analysis demonstrated that the primed seeds of both cultivars and production conditions showed higher expression of transcripts involved in cellular respiration and reserve mobilization, cell elongation, cell wall loosening and biosynthesis of cell wall, which may indicate the beneficial effects of priming on physiological performance in primed seeds during germination.