Overcoming dormancy of seeds of Copaifera arenicola (Ducke) J. Costa & L. P. Queiroz

ABSTRACT: Seed dormancy can occur due to a combination of intrinsic factors and stimuli from the external environment. From a production perspective, it is an undesirable characteristic, as it hinders germination and limits production. This study aimed to identify the type of primary dormancy and determine the most efficient method to overcome it in seeds of Copaifera arenicola (Ducke) J. Costa & L. P. Queiroz (Fabaceae), a tree species endemic to the Caatinga. The experiment was conducted in a completely randomized design, with 52 experimental units distributed in 13 treatments with four replications. The treatments included scarification (mechanical and chemical), hot stratification, use of growth regulators, washing/leaching, soaking and control. Germitest paper was used as substrate in germination chambers (B.O.D) under alternating temperatures of 20-30 ± 2 °C and a 12-hour photoperiod (white light). Seeds with root protrusion ≥ 2 mm were considered germinated, evaluated at two-day intervals. The following parameters were analyzed: first count and total germination percentage; mean germination time and rate; speed index, uncertainty and germination uniformity coefficient. The data were subjected to ANOVA, and the means were compared by Tukey test (p ≤ 0.05). The dormancy mechanism identified was physical. The most effective treatments to overcome dormancy were: chemical scarification with sulfuric acid (H₂SO₄-98%) for 10 and 5 minutes; mechanical scarification (abrasion with 100 grit wood sandpaper) without additional treatment; and scarification followed by immersion in potassium nitrate (KNO₃) for 30 minutes.