Abstract: Accelerated ageing soybean seeds with different viability were used as materials,their germination time-course in 20 ℃ and dark incubation were described with three level polynomial regression curve,and germination rate curves were also described in differential functions of germination curve.Based on the comparison of parameters in both types of curves established in different ageing soybean seeds,e.g.germination origin and transmitting,it is found that  founded regression curves include much more information than traditional germination parameters;furthermore,they are  more sensitive and accurate.

Key words: polynomial regression, seed vigor, germination origin, maximum germination rate