Effect of different substrates on the domestication of Saba comorensis (Bojer) Pichon (Apocynaceae), a spontaneous plant used in agroforestry system

Saba comorensis is a multipurpose woody liana which is threatened in Western Africa due to deforestation. To protect it from future extinction, the present study was carried out and aimed to evaluate the effect of different substrates on seed germination and seedlings growth in nursery. Fresh unpulled seeds were sown in polyethylene bags arranged in sub-blocks and containing the following substrates: cocoa pod + topsoil (¼; ¾), sawdust + topsoil (¼; ¾), poultry dung + topsoil (¼; ¾), rice bran + topsoil (¼; ¾) and only topsoil serving as control. The germination data obtained after regular watering for 35 days and growth data during 5 months were analyzed throughout R software for a one-way analysis of variance using the appropriate tests to establish significant differences. Results showed that the highest germination rate was obtained with the sawdust + topsoil mixture and the control (58.33% each). On the other hand, the latency time was better with the sawdust + topsoil mixture (16 days) than all the others. There was a significant difference (p˂0.05) in height between the plants obtained from the sawdust + topsoil mixture (28.45 ± 1 cm) and those from the other substrates, except for the plants bred in poultry dung + topsoil mixture (25.70 ± 1.25 cm). Thus, in view of these results, the mixture of sawdust + topsoil (¼; ¾) is suitable for ensuring the domestication and conservation of Saba comorensis.