White Guinea yam is widely grown in the West African coastal region (Guinea Savanna) and is an important crop that supports food supply and demand in this region. However, the labor-intensive cultivation of white Guinea yams is a major burden on farmers. In collaboration with the International Institute of Tropical Agriculture (IITA) in Nigeria, JIRCAS has now clarified the effect of flowering sex on tuber yield of white Guinea yam, which has not been well understood for a long time. This achievement reveals the possibility of yield improvement through flowering control in yams.