Seed Germination and Growth of Irvingia gabonensis (Aubry-Lecomte ex O'Rorke) Baill. (Irvingiaceae) Seedlings in a Controlled Environment East of Taï National Park (Buyo, South-West of Ivory Coast)

Abstract

Anthropogenic activities tend to destroy forest resources such as Irvingia gabonensis, a species much prized by the local populations of the Taï National Park (TNP). The enormous pressure on the natural stands of this species is leading to its rarefaction and even extinction. This study was to identify the best methods for germinating Irvingia gabonensis seeds, with a view to facilitating their integration into cropping systems on the outskirts of the park, with a view to conserving the species and promoting nutritional security. The methodological approach consisted of a series of five (5) treatments to lift dormancy and control seeds (T0) and measure germination and seedling growth parameters, all in a randomised Fisher experimental set-up. In order to control soil moisture, watering was carried out morning and evening, except in the event of rain. The seedlings were placed under a shade canopy to reduce their exposure to light. The results showed that seeds subjected to treatments T3 (soaking seeds in 33% dilute sulphuric acid for 96 h followed by rinsing with well water), T4 (soaking seeds in well water for 96 h) and T5 (manual scarification of seeds using a lime) had a better germination rate (83.33%, 80% and 66.66% respectively). The shortest germination times were recorded in T5 (5 days), T2 (heating at 45°C for 10 min followed by soaking the seeds in well water for 24 h) and T3 (8 days) and T1 (soaking the seeds in well water for 24 h followed by heating at 45°C for 10 min) with 11 days. T1 and T4 gave the shortest germination times (4 and 6 days respectively). In addition, the height growth of seedlings from T2, T3 and T4 was better. However, serious regressions were observed in the diameter growth of seedlings from T2 and T3 after 21 days. Treatments T3 and T4 are the most appropriate for growing Irvingia gabonensis. The results of this research could be applied to the conservation of Irvingia gabonensis by facilitating its integration into local cropping systems, thereby improving agricultural practices.