Samples of five commercial seed lots B. dictyoneura from Colombia, Panama and Costa Rica of identical age were studied in a series of laboratory trials. To characterice the physical and physiological dormancy as well as its dynamics in time. Complete spikelets, spikelets scarified with sulfuric acid during 30 minutes, an naked caryopses of each sample were exposed to treatments as follows: 1. Application of different dry-heat regimes with three temperature levels (ambient, 40 and 6CJ>C) and three times (0, 72 and 240 hours), at 1 and 3 months after harvest. 2. Application of Gelvatol in combination with hydration, dehydration, potassium nitrate application, and low temperature treatment. The Gelvatol treatment was compared with an application of a 0,2% potassium nitrate solution; the control treatment was water. The seed dormancy is high and persistent even eleven months post harvest. Two forms o f seed dormancy could be detected, one physiological, the other physical associated with external coats of seeds. The physiological form is minimal at three months while physical form is high even six months after harvest. Complete spikelets maintened a high level of dormancy (73-83%) even eleven months after harvest. Application of Gelvatol and potassium nitrate reduced dormancy of seeds only nine months after harvest. In contrast, acid-scarified spikekelets showed a progressive decrease of dormancy with time, reaching a minimum value at six months after harvest. Dry heat, particularly 60 ° C improved Normal Germination until six months after harvest. After six months the dry-heat regimes were similar to acid scarification only.