Effect of different mechanical seed scarification methods on germination and emergence dynamics of baobab (Adansonia digitata L.)

The African baobab (Adansonia digitata L.) is a multipurpose fruit-producing tree that is indigenous to the African savannahs. Commercial interest in the species has grown in recent years. The major obstacle of seed-based propagation of baobab is its inherent seed dormancy. Therefore, in this study the effects of different mechanical seed scarification methods on seed germination parameters and seedling development of A. digitata were tested. The results show that mechanical scarification had a significant effect on germination and emergence dynamics of A. digitata. The highest total emergence percentage with 61.7% was achieved by scarifying the seeds with a saw on the hilum side. Cotyledon damage due to mechanical scarification occurred in all treatments. Proportions of damage categories depended significantly on treatment. The largest proportion of undamaged cotyledons was with 63.6% achieved by scarifying the seeds with a saw on the hilum side. This precise technique may be suitable for mass propagation of baobab in a rural setting but the effects of scarification methods on seedling emergence should be further investigated.