Effect of mechanical scarification and gibberellins (GA₃) on seed germination and growth of <i>Garcinia kola</i> (Heckel)

Abstract

Objective: Garcinia kola (Heckel) in general has been shown to have a low germination and this constitutes a real obstacle to any domestication initiative. The experiment was conducted in an attempt to improve seeds germination.
Methodology and results: Scarification in combination with Gibberellins (GA3) application and soaking in distillated water was carried out on fresh seeds and sown in two types of soil substrate: sandy topsoil (1/1) and 100 % topsoil. Parameters related to seed germination and seedlings vigour was evaluated. Results indicated that substrate do not affect seed germination and plant vigour. However, the percentage of germination (92.33±3.19) and germination rate (0.013 ±0.00) were highest when scarified seeds were soaked in increasing concentrations of GA3 (10-4 to 10-2 g L-1). In addition, scarified seeds soaked in distillated water have improved percentage of seed germination. Concerning plants vigour, GA3 application increased significantly plant height (11.22±4.31 cm) and plant wingspan (13.35±6.36 cm) against 9.19±4.17 cm and 11.67±6.78 cm for plant height and wingspan in the control.
Conclusion and applications of findings: Results suggest that G. kola seeds present seed coat dormancy. Scarification and GA3 application offer possibly an alternative methodology to improve seed germination and seedling vigour for a large-scale production of G. kola seedlings, a prior step of plant species domestication process.

Keywords: Garcinia kola, seed coat dormancy, mechanical scarification, GA3, seed germination