Soybean physiological seed quality evaluation after hydration-dehydration process and accelerated aging

A work was carried out with the purpose of evaluating the physiological qua lity of osmoconditioned soybean (Glycine max (L.) Merrill) seeds of UFV-10, IAC-8 and Doko RC varieties, in terms of response to stress induced by the accelerated aging test. Seeds were osmoconditioned in PEG 6000, with an os motic potential of -0.8 MPa and 20 degrees C of temperature, for four days. After that, seeds were dried back to the initial moisture content and subm itted to the accelerated aging test for the following periods: 0, 24, 48 an d 72 hours. Two controls were used: untreated seeds and seeds soaked in wat er. After several determined accelerated aging periods, seeds were evaluate d by the standard germination test, seedling length and dry biomass of seed lings. In greenhouse the speed of emergence-index and the final emergence i n sand seedbed were determined. Soybean seeds hydration-dehydration treatme nt in PEG 6000 solution improved seed performance in relation to germinatio n and vigor. The extent of the accelerated aging period affected seed perfo rmance in all parameters evaluated. However, PEG 6000 treatment was satisfa ctory in maintaining the seed quality during the accelerated aging periods. The soybean seed water soaking affected negatively the physiological seed quality. The soybean varieties showed differential response to the hydratio n-dehydration treatments and to the accelerated aging periods.