TREATMENTS FOR SEED DORMANCY RELEASE IN Brachiaria humidicola (Rendle) Schweick

Abstract

Most of the tropical forages is affected by seed dormancy, which can hinder the determination of its physiological quality, field seedling emergence, and the establishment of pastures. This study aimed to evaluate the effectiveness of acid scarification and application of germination promoters on the dormancy release of stored seeds of Brachiaria humidicola. Seeds stored during nine and 21 months were scarified with the aid of concentrated sulfuric acid. Afterwards, the seeds were placed to germinate on a blotter paper moistened with the following solutions: KNO₃ (0.2%), gibberellic acid (100 mg L^-1), H₂O₂ (0.30%), and distilled water. The seeds remained for 21 days under an alternating temperatures regime (15-35ºC) and light cycles (8 hours of light/16 hours of darkness), when the percentages of germination and dormant seeds were evaluated. Acid scarification was more effective on dormancy release in the seeds stored up to nine months, in comparison to the ones stored for 21 months, with reduction of dormant seeds percentage from 84% to 36%. Acid scarification of seeds stored up to nine months, followed by the gibberellic acid treatment, or the storage of seeds up to 21 months resulted in a 60% germination rate. The storage of B. humidicola seeds up to 21 months is more effective for dormancy release than the acid scarification or the application of germination promoters.