Phenology of Bobgunnia madagascariensis (DESV.) J. H. Kirkbr. & Wiersema and Euphorbia sepium N.E. Br. in relation to climatic factors in the Sudano-Guinean zone of Benin

Bobgunnia madagascariensis and Euphorbia sepium are two galactogenic species used for livestock farming in Benin. However, there is a few studies on these two species, especially about their characterization and phenology. Knowing plant phenology provides a useful understanding of their autoecology and contributes to conservation and management strategies. The study aimed to describe in relation to climatic factors the different phenological stages of B. madagascariensis and E. sepium in the Sudano-Guinean zone of Benin. Trees spaced at least 13 m apart were chosen randomly and ten individuals of each species were identified and monitored. The observations were made on the phenological stages of both species and were carried out every 10 days during two years in the municipality of Nikki located in Sudano-Guinean zone of Benin. The results shown a single phenological stage (leafing) on E. sepium , characterized by alternating leaf emergence from March to October and leaf fall between November and February. However, three phenological stages were observed (leafing, flowering and fruiting) on B. madagascariensis . Leafing occurred from March to November, flowering from May to August and fruiting from July to February. Peak flowering and fruiting were observed in May-June and August-September, respectively. Leafing of both species was positively and significantly correlated with rainfall. Minimum temperature was positively and significantly correlated (r = 0.61) with flowering on B. madagascariensis . However, fruiting in the same species was negatively correlated (r = -0.89) with maximum temperature. This study provides important information for a better valorization and in situ conservation of the two species in Benin.