The objective of this research was to study the effects of thermal and chemical treatments on Brachiaria brizantha cv. Marandu seeds, particularly in relation to dormancy. Seeds presenting dormancy indices higher than 25% and physical purity above 98% were submitted to temperatures of 65, 70, 75 and 80 °C for periods of 5, 10 and 15 hours and to immersion in sulphuric acid (98%, 36N) for 15 minutes. At the beginning and at the end of six months storage under uncontrolled laboratory conditions, seeds were evaluated in relation to germination, tetrazolium (viability), first count of germination, seedling shoot lenght, seedling emergence and speed of emergence index. Some specific thermal treatments showed positive effects similar to sulphuric acid treatment in reducing seed dormancy without causing latent physiological deterioration; 70°C/15h was the best thermal treatment to dormancy reduction in cv. Marandu.
seed storage; vigor; sulfuric acid; seed dormancy
