Physical and chemical methods to breach seed dormancy of sugar apple

Abstract

Cultivation of sugar apple has increased in the Setentrional Amazon, but one of the problems for obtaining quality seedlings is related to overcoming dormancy of its seeds. The objective of the present study was to evaluate the efficiency of physical and chemical methods to break sugar apple seed dormancy. Ripe sugar apple fruit were collected from an orchard located in Boa Vista-RR, pulped and their seeds washed in running water and dried in the shade for 24 h. A completely randomized experimental design was used in a factorial 2 (0 and 1000 mg L–1 GA3 = gibberellic acid) × 4 immersion times (0, 6, 12 and 24 h) × 2 (with and without scarification) with 4 replications and 50 seeds per replication. The seeds were then sown in beds under greenhouse-type shade with 50% brightness in soil and sand mixture (3:1 v / v) subtrate. The following were evaluated 30 days after sowing: percentage of emergence (%) and shoot growth after seedling emergence, at four-day intervals. At fifty‑eight days after sowing, the shoot and root lengths, number of leaves, shoot and root dry matter were assessed. The highest sugar apple seedling emergence speed and growth rate were obtained when the seeds were subjected to the method of scarification and soaking in GA3 for 12-24 h. Scarification and soaking in water for 24 h resulted in greater economy, practicality and financial savings.