Utilização de métodos físicos e de fitorreguladores para superação de dormência em sementes de pinha

Abstract

The custard apple is a very popular fruit because of the flavor, and can be propagated by seed or grafting. However, the production of seedlings per seed propagation is hindered by the strong seed dormancy. The objective was to determine the best treatment for overcoming pine cone seed dormancy (Annona squamosa L.), submitting them to pregerminative mechanical and non-mechanical combination treatment. The completely randomized design in 4 × 2 factorial arrangement with four replicates were used. Treatments consisted of four pre-germination treatments not mechanical in combination with mechanical pre-germination treatment (presence or absence) with mechanical scarification with sandpaper. The treatments were: T1 - control without scarification; T2 - mechanical scarification; T3 - Ethrel (500 mg L -1 ); T4 - Ethrel (500 mg L -1 ) + mechanical scarification; T5 - hot water (60 °C for 1 minute); T6 - hot water (60 °C for 1 minute) + mechanical scarification; T7 - gibberellic acid, GA 3 (1000 mg L -1 ); T8 - gibberellic acid, GA 3 (1000 mg L -1 ) + mechanical scarification. The germination, time, index and germination rate, and length of primary root were measured. The pre-germination treatments of pine cone seeds with gibberellic acid in combination with mechanical scarification is the preferred method for breaking dormancy of this species.