Comparison of East and West African populations of baobab (Adansonia digitata L.). (Special Issue: Fruit trees in West African parklands.)

摘要

The baobab tree (Adansonia digitata L.) is of large socioeconomic importance. However, domesticated plant material of baobab is rarely available to African farmers, and very limited pre-breeding knowledge is available. To evaluate genetic differentiation between geographical origins we compared vigor and leaf morphology of trees from 17 West African and 13 East African provenances of baobab. Seedlings were grown and evaluated in a common garden test at Bamako, Mali. Germination was assessed and growth measured 3 and 12 months after germination. Leaf morphology (leaf length, leaflet number, petiole length and diameter and leaflet border) were assessed after 12 months. Significant differences between the provenances were observed for both growth rate and leaf morphology. West African provenances in general grew faster than East African provenances, but leaf characters did not reveal a particular geographic structure, and the correlations between geographic distances and multivariate Mahalanobis distances were not significant. The correlations between leaf morphological traits and climatic data were in general low at the provenance level. However, the number of leaflets was significantly higher for provenances from drier areas. Two years increment at a field site also varied significantly between the provenances, where West African provenances confirmed their tendency to higher growth rate. Still, trees are young and results regarding both growth data and leaf characteristics should be confirmed when the trees are closer to maturity.