Aiming at to improve the methodology for application of heat to break dormancy seeds of Brachiaria brizantha `Marandu', the physiological performance of samples of ten seed lots of this forage, with dormancy indices superior to 25%, was studied after exposure to 70 ºC for 5, 10, 15, 20, 25 and 30 hours and immersion in concentrated sulphuric acid for 15 minutes. At the beginning (immediate effect) and after six months (latent effect) storage under ambient uncontrolled conditions, the following evaluations were made: water content, germination, tetrazolium viability, sand emergence, speed of emergence index and shoot length. Results indicated that exposure of seeds to 70 ºC or to concentrated sulphuric acid reduce the dormancy rate and favor the physiological performance; after six months, the seeds submitted to 70 ºC for 5 hours show performance superior to those of the other treatments.
signalgrass; dormancy; dry heat; chemical scarification
