Avaliação da qualidade fisiológica de sementes de soja, após o processo de hidratação-desidratação e envelhecimento acelerado

Abstract

A work was carried out with the purpose of evaluating the physiological quality 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 osmotic potential of -0.8 MPa and 20°C of temperature, for four days. After that, seeds were dried back to the initial moisture content and submitted to the accelerated aging test for the following periods: 0, 24, 48 and 72 hours. Two controls were used: untreated seeds and seeds soaked in water. After several determined accelerated aging periods, seeds were evaluated by the standard germination test, seedling length and dry biomass of seedlings. In greenhouse the speed of emergence-index and the final emergence in sand seedbed were determined. Soybean seeds hydration-dehydration treatment in PEG 6000 solution improved seed performance in relation to germination and vigor. The extent of the accelerated aging period affected seed performance in all parameters evaluated. However, PEG 6000 treatment was satisfactory 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 hydration-dehydration treatments and to the accelerated aging periods.