Variation in Hyphaene thebaica Mart. fruit: physical characteristics and factors affecting seed germination and seedling growth in Benin (West Africa)

摘要

Hyphaene thebaica (dum palm) is an important tree species that grows wild in the semi-arid regions of tropical Africa. Increased knowledge on the effect of stress on the propagation and establishment of these plants is needed to optimise its domestication. This study assessed the physical characteristics of H. thebaica fruit harvested from three phytodistricts in Benin. The germinability of the seeds, before and after water-soaking and removal of the seed coat, was tested, and the number and size of the leaves produced in the resulting seedlings were measured. Hierarchical classification of the characteristics of fruit revealed the existence of three morphotypes. A Factorial Discriminant Analysis performed on these morphotypes revealed highly significant differences (P = 0.001). Morphotype 3 (48 seeds) had the highest rate of seed germination (49.99%) and the widest leaves (28 mm) over the 154 d of the experiment. Seedlings of morphotype 2 and morphotype 3 (48 seeds each) had the highest number of leaves (two per seedling), whereas only morphotype 2 seedlings had the longest leaves (35 mm). Results from Analysis of Variance revealed that the time of germination and water-soaking had significant effects (P = 0.05) on seed germination. The study also showed that the growth of seedlings differed with the time of germination, and that these differences varied with morphotype. These results may be used to improve current propagation and conservation strategies in this species in its areas of origin.