Main Physiological Factors Affecting the Germination of Annona muricata L. Seeds

Abstract

Dormancy and latency factors such as moisture content, temperature, growth regulators, and seed-coat affecting germination of the Annona muricata L., a tropical fruit, were studied. Three types of fruits were used with presence of stylar residues (medium and big size) and absent of stylar residues. The fruits were taken from 4-year-old trees, which were naturally pollinated. A complete randomized design was used for the study, with 50 seeds per experimental unit and four replications per treatment. The variables measured were days and percent of germination, and average germination velocity. The seed germination was affected by the moisture and oxygen content, because the structure of the seed and their high content of the lipid in there. The length of the germination period was determinated by the concentration of the exogen hormones applied, the temperature range, the kind of scarification used, the substrate utilized and the moisture content present during the assays. Highly significant differences were found among treatments. The optimal conditions for germination (97.5%) were: 30 °C of temperature, no scarification, sand as substrate, and 750 ppm of gibberellic acid. The average of days to germination was 24.5 days. No significant differences were found for the different kind of fruits used in this assay. The results showed that this species presented characteristics of recalcitrant seeds.