Yams — West Africa’s Corner on the Market

Context Global Development
5 min readMar 25, 2021

Commodity Report. Originally published June 2018.


Yam yields in Nigeria and Ghana are low, largely because the quality of seed yams sourced from the informal seed system is poor and disease pressure is high. A project funded by a multi-year grant to the International Institute of Tropical Agriculture (IITA) from the Bill & Melinda Gates Foundation aims to strengthen the entire yam value chain, from smallholder farmers to yam processors and international exporters. (Photo: Yams produced in Nigeria)

Yams present a conundrum in West Africa. While consumer demand is high, yam yields are chronically low, stymied by poor seed quality, intensive labor requirements, disease pressure, limited use of fertilizer or crop protection, and more.

West Africa accounts for 96% of the world’s yam production, with Nigeria alone producing two-thirds of the global yam crop. Ghana, also in West Africa, is the second-largest yam producer, with about 10% of the global total.

Challenging, But Profitable

Most of the yam production is by smallholder farmers in the Savannah region, with farm sizes of about one-half hectare (1.25 acres). “Farmers in this savannah region are usually resource poor and rely on rainfall for irrigation. They experience some of the highest rainfall variability in the world, both within a season and year-to-year,” says CGD Senior Program Manager Jason Nickerson. Furthermore, smallholder yam production is uniquely labor intensive. Because cultivated yams produce no seeds, tubers or pieces of tuber must be planted in prepared soil to grow new plants. Prior to planting, the soil must be mounded to receive the seed.

As soon as plants begin to grow, a framework or trellis is needed to support the 35- to 40-foot vines. Yams are often grown next to trees or intercropped with maize or sorghum where the stalks can provide support. At the beginning of the dry season, the vines die away, and the tubers are ready to be harvested. Typically, tubers weigh between 6 to 12 pounds (3–6 kg) each, although special production systems can yield tubers as large as 60 pounds (about 27 kg). Yams are usually dug out by hand to avoid damaging the tubers.

When harvested undamaged, yams are among the most storable root and tuber crops. Stored yam tubers provide food security in the dry season when other crops can fail, thus serving as a crucial, natural hedge for farmers and their families. Moreover, consumer demand for yam is robust in West Africa, rewarding farmers for their efforts.

Where Is the Research?

Against this backdrop, it is notable that yam value chains in Nigeria and Ghana are underdeveloped, with the formal seed system contributing only ~2% of total yam planted area in Nigeria.This translates into low yam yields in both countries, largely because the quality of seed yams sourced from the informal system is poor. Given yam’s pivotal role in the lives and livelihoods of farmers, it is somewhat surprising that yam has not received the research and financial support needed to set a clear path toward increasing the value of yam cultivation, according to CGD Managing Director Mark Nelson.

The development of a formal yam seed system is critical to improving yields in Nigeria and Ghana, but it has been hindered by several factors including low seed propagation rates, a lack of collaboration between the research community and processors, and farmer uncertainty around the benefit of purchasing improved seeds. As a result, the yam value chain remains unattractive to private sector investment. While the Nigerian government has made some investments in yam, programs have been modest. Opportunities to meaningfully improve the value chain remain. In contrast, governmental support for yam in Ghana is further along. The difference represents an opportunity to promote a shared learning agenda.

At present, a champion to drive needed change has not emerged: (1) industrial companies are not of scale, (2) while support is present in Ghana, the Nigerian government has not yet made yam a priority crop, and (3) few donors have invested in yam-centric programs.

Opportunity for Development

Improving the value chain for yam seed producers in Ghana and Nigeria requires a systematic and multifaceted approach. On the supply side, limited production of early generation seed is a major constraint toward improving yam yield. Yam is traditionally propagated by tuber, with a low multiplication rate of less than 1:10, compared to 1:200 in many cereals. The situation is worsened by the long growth cycle of yam. The introduction and adoption of rapid multiplication technologies developed and piloted by the International Institute of Tropical Agriculture (IITA) and partners, such as temporary immersion bioreactors, aeroponics, and adapted yam minisett technology can increase the rate of propagation, improve production economics, and accelerate the introduction of improved varieties.

On the demand side, yam processors are reluctant to invest in new processing capacity without an assurance of a steady supply of high-quality tubers. Conversely, private seed companies are reluctant to invest in high-tech seed production processes without strong indications that farmers are willing to pay a premium price for improved seed.

The Yam Improvement for Income and FoodSecurity in West Africa (YIIFSWA) project, granted to IITA in September 2011 by the Gates Foundation, is a two-phase, multiyear program that addresses challenges facing yam production in Nigeria and Ghana. Key objectives of YIIFSWA include strengthening smallholder farmer-market linkages and establishing sustainable improvements in production of clean, improved seed yam.

IITA is leading the project. Phase two of the project commenced in November 2016. Intended beneficiaries of the project extend through the entire supply chain from seed producers, farmers, processors, traders, and their surrounding communities. Under YIFSWA II, CGD is working with IITA, the national partners, and Sahel Capital to build the first formal seed yam marketplace in Nigeria and Ghana. Accelerating market uptake of improved varieties is critical to the goals of the project. By stimulating widespread adoption and ensuring the impact of breakthrough seed production technologies, the project seeks to solve the dual challenges of high scarcity and low investment in the high-quality seed yam market.

The project team is working closely with private seed companies to implement business plans and organize trials demonstrating the value of quality seed yam. These efforts are aimed improving and enabling the scale-up of private seed companies. CGD’s Nelson says: “It’s rewarding to be able to tap our private sector experience to offer guidance on business models that sharpen the marketing and operational skills of private seed companies in Nigeria and Ghana using aeroponic systems for basic seed yam production. Working with partners, we believe there is tremendous potential to improve the economics across the yam value chain by strengthening the early generation seed (EGS) system and localizing seed production.”



Context Global Development

Context Global Development® (CGD) is a non-profit organization that leads agricultural and social impact programs worldwide.