Six different levels of vigour of sorghum seeds from an identical lot were obtained through accelerated aging for various periods of time. Vigour was estimated according to yielding ability of the seed in the field. After 6 d of aging, seed invigoration, to the extent of a 20% increase in yield, was observed. However, this was followed by a gradual decrease in yield following aging of up to 48 d. All seed lots showed 88–92% germination or emergence capacity when tested in the laboratory, which correlates poorly with vigour. However, vigour correlated well with the rates of germination and root emergence when tested in the laboratory, as well as with emergence rate in the field.