Soybean seeds were primed in a laboratorial study with 1% solution of potassium nitrate for 24 hours at 20°C and tested under field conditions in Iran. According to the results from the laboratory experiments, germination percentage, germination rate and seedling dry weight were improved. In the field study, seeds primed with KNO3 showed the highest values for all of the evaluated traits; the number of pods per plant, the number of seeds per pod, 1000-seed weight, height, LAI and the yield (Table 1 and 2). Seed priming significantly improved the soybean plant traits compared to the control (no priming).
Table 1. The results of the KNO3 and control treatment for the laboratorial traits: germination percentage (GP), germination rate (GR) and seedling dry weight (SDW).
Table 2. The results of the KNO3 and control treatment for the field traits: number of pods per plant (NPPP), number of seeds per pot (NSPP), 1000 seed weight (1000-SW), height (H), leaf area index (LAI) and seed yield. 
