SEED STRUCTURE AND GERMINATION OF CHERIMOYA (ANNONA CHERIMOLA MILL.)
Different pre-applied treatments, soaking in different concentrations (ranging between extreme values of 500 – 10,000 ppm) of gibberellic acid (GA3), soaking for different periods (12 – 72 hours) in distilled water and chemical scarification with sulphuric acid were evaluated in germination percentage and germination rate. Gibberellic acid showed a clear positive effect on both germination percentage and rate, although no significant differences between different concentrations were noted. Soaking in distilled water for 48 – 72 hours or 12 hours in gradually cooling water (initial temperature 92 °C) also showed a significant effect although germination was much more spread over time and irregular, making it a cheaper though less effective alternative for phytohormone treatment. Significant differences between the control, and water and gibberellic acid pre-applications suggest the presence of dormancy in cherimoya seeds.
Germination was evaluated during a period of 900 days, at the end of which germination was still occurring although reduced to very low levels. Germination varied between 10 – 74.5% after 98 days and ranged 49.5 – 77% after 900 days over the different treatments. Uncontrolled temperature regime may probably account for similar peaks in the different germination curves.