|Authors: ||S. De Smet, P. Van Damme, X. Scheldeman, J. Romero|
|Keywords: ||dormancy, Andean fruits, gibberellic acid, pre-application treatment|
Uneven and irregular germination of cherimoya (Annona cherimola Mill.) seeds results in difficulties in propagating this fruit tree.
Prior to a germination test, structures of the ungerminated and germinating seed were studied and the different parts described.
It was found that cherimoya embryo is small (3 – 4 mm) and located inside an impermeable testa, with the micropyle being the only entrance for water.
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.
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