Sugar apple (Annona squamosa L.) seed germination affected by the application of gibberellins

This research sought to establish the response of the germination percentage (PG), synchrony index (E), mean germination time (MGT) and mean germination rate (MGR) of Annona squamosa L. seeds from Apulo (province of Cundinamarca) and Castilla (province of Tolima), Colombia, to treatments with 0, 50, 100, 200, 400, 600, or 800 mg L-1 of gibberellic acid (GA). All of the treatments with GA increased the PG at each point of time of seed incubation. The 600 mg L-1 GA treatment resulted in higher PGs (92.3% at 16 days for Apulo and 95% at 24 days for Castilla) and lower MGTs (8.75 and 5.38 days for Apulo and Castilla, respectively) than those found with the concentration of 0 mg L-1 GA (17.68 and 10.88 days for Apulo and Castilla, respectively). Also, treating the seeds with 600 mg L-1 GA generated higher MGRs (0.18 and 0.12 germinated seeds/day for Castilla and Apulo, respectively) than those obtained with 0 mg L-1 GA (Castilla = 0.09 and Apulo = 0.06 germinated seeds/ day). Likewise, the germination was synchronized with the application of any concentration of GA. The results evidenced a positive response to the GA application, which provided a tool for the characterization of the phenomenon of dormancy in the A. squamosa seeds.