History, current status, and prospects of soybean production and research in sub-Saharan Africa

Soybean (Glycine max (L.) Merr.) is a non-native and non-staple crop in sub-Saharan Africa (SSA) with potential to be a commercial crop owing to its wide range of uses as food, feed, and industrial raw material. Soybean was first introduced to SSA by Chinese traders in the 19th century and was cultivated as an economic crop as early as 1903 in South Africa. In the past four decades, soybean cultivation area and production in SSA has increased exponentially, from about 20,000 ha and 13,000 t in the early 1970s to 1,500,000 ha and 2,300,000 t in 2016. Soybean yield has been stagnant in SSA for decades at about 1.1 t ha−1, much lower than the world average, representing one of the most challenging issues in the soybean industry in SSA. The low soybean yield in SSA can be attributed to the use of poor-performing varieties and to the limited application of fertilizers and rhizobial inoculants in soils with no history of soybean production. South Africa, Nigeria, Zambia, and Uganda are the leading soybean producers in SSA. Soybean research in SSA is conducted by international and national research institutions, including IITA, national soybean improvement programs, universities, and the private sector. Between 1970 and 2011, 195 soybean varieties were released by IITA, private breeders, and national soybean improvement programs in SSA. This paper reviews the history and current state of soybean production and of the utilization and adoption of tropical varieties in SSA, addresses the major soybean yield-limiting factors across the region, and discusses the potential of the soybean industry in SSA. It also highlights soybean improvement efforts and lessons learned from previous soybean improvement efforts and the current progress of some national soybean improvement programs in SSA. Opportunities for scaling up tropical soybean as a major crop across SSA countries are promising. Keywords: Soybean, Sub-Saharan Africa (SSA), History, Current status, Prospect