Breaking dormancy in Brachiaria brizantha (Hochst. ex A. Rich.) Stapf seeds

Abstract

The seed dormancy of Brachiaria brizantha is responsible for the lack of uniformity and low booth production fields. The nature, intensity and persistence of this phenomenon are not sufficiently elucidated. The objective of this work was to evaluate methods for overcoming seed dormancy of two cultivars of Brachiaria brizantha, whether or not they were treated with fungicides - carboxin (20.0% m/v) + tiram (20,0% m/v). The study was conducted in factorial scheme 2 x 4 x 2 (cultivars x treatments to overcome dormancy x without and with fungicide). The cultivars tested were MG-5 and Marandu. The four treatments for rupture of dormancy consisted of scarification with sulfuric acid (H₂SO₄ – 98%, 36N) during 10 and 15 minutes, treatment with water at room temperature of 21.7 ºC, besides the control. Seeds were evaluated in germination trials at 7 and 21 days (end of trial). The treatment of seeds with the fungicides had no positive effect on dormancy and percentage of germination of 'MG-5' and 'Marandu' cultivars. The seeds of the two cultivars reacted very differently to the pre-treatments.