Morphological diversity of Bobgunnia madagascariensis (Desv.) J. H. Kirkbr. & Wiersema, across the Sudanian and Sudano-Guinean zones of Benin Republic

Abstract

• Three morphotypes of Bobgunnia madagascariensis were identified in Benin. • Phyto-geographical zones affects the repartition of Bobgunnia madagascariensis. • High correlation exists between B. madagascariensis fruit length and fruit width. Although Bobgunnia madagascariensis is an important tree species known in traditional medicinal with a well-recognized galactogenic properties, it remains poorly documented. In Benin, little information is available on this species which is highly threatened in its natural habitat. In this study, the morphological variability of 51 trees of B. madagascariensis from Sudanian (28 trees) and Sudano-Guinean zones (23 trees) of Benin was evaluated using 20 descriptors, including 7 qualitative and 13 quantitative traits. A hierarchical ascending classification followed by principal component analysis, analysis of variance and quantitative traits correlation analysis were used to describe the intraspecific diversity of B. madagascariensis in the study areas. Analysis of morphometric data revealed the existence of three morphological groups within the species with a distinct morphological organization among the trees sampled. The discriminating morphological descriptors included the total height of the tree, the diameter at 1.30m, the bole height, the leaf length, the number of leaflets of the leaf, the fruit weight, the fruit length and width, as well as the seed length and weight. Individuals in group 3 had the highest values for nine of the 10 most discriminating traits. A significant and positive correlation was found between trees’ total height and seed length, as well as between fruit traits (fruit weight, fruit length) and seed traits (seed weight, seed length). In addition, the diameter at 1.3 m was positively correlated with the leaf width. The results also revealed a significant difference between the trees observed in the Sudanian zone and those in the Sudano-Guinean zone with the number of leaflets, the petiole length, the fruits width, the seeds weight and length as discriminating traits. This study provided preliminary data on the morphological variability of B. madagascariensis and will serve as basis for a selection, conservation and domestication program.