Effect of pre-germination treatments on the dormancy breaking and early growth performance of bitter kola (Garcinia kola- (heckel) in south southern Nigeria

Abstract

The demand for bitter kola (Garcinia kola) is high in Nigeria market but the population of the species is low both in the wild and home gardens. Rapid deforestation, heavy exploitation in the natural forest and difficulties associated with its germination occasioned by seed dormancy have been blamed. The study on enhancing germination and early growth of Garcinia kola was conducted using Complete Randomized Design (CRD) with three treatments and a control. The control was made of untreated seeds (T₁) while the treatments included nicked seeds soaked in water for 24 hours (T₂), seeds from fermented pods (T₃), and seeds from fresh pods (T₄). Seed germination tests were carried out after pre treatment using 16 seeds for each treatment anf the control in the nursery site of the Cross River University of Technology (CRUTECH, Obubra campus) in South southern Nigeria.. The result showed that cutting seeds at the opposite end to the radicle (nicking) was the most suitable pre-sowing treatment to increase seed germination and early growth performance of Garcinia kola. Treating the seeds with mechanical scarification (nicking) significantly enhanced germination (P<0.001) and significantly influenced seedlings growth (P<0.05). The highest mean values of 8, 14.65 cm and 5 were obtained for germination count, plant height and leaf number respectively from nicked seeds soaked in water for 24 hours. Dormancy in Garcinia kola seeds can be removed by nicking the seeds and soaking in cold water for a day.

Keywords: Germination, growth, seed nicking, pre-treatment, dormancy