Sweet potato harvest in Uganda

Despite a common (trust us, it's not just you) misconception, sweet potato (Ipomoea batas L. Lam) is not at all related to potato (Solanum tuberosum), nor to the true yam (Dioscorea batatas). In fact, they are all quite different. Sweet potato is a root crop, and potato and yams are tuber crops. Even researchers sometimes get confused that their publications mistakenly relate the crop species and data.

For example, some countries reported the production of sweet potato as yam, and vice versa. Some countries still combine sweet potato and yam in the same category as an aggregate.

Useful Facts about Sweet Potato in Sub-Saharan Africa

  1. Sweet potato belongs to the morning-glory family, and it was originated in Latin America and is thought to have been brought to Africa by slave traders.
  2. The growth period for sweet potato is 3-7 months. In countries with two rainy seasons (e.g., Rwanda, Burundi, Uganda), sweet potato is available in the market 11 months of the year and is a primary staple. Elsewhere in Africa, it is available 4-8 months of the year.
  3. Sweet potato is the 3rd most important food crop in seven East and Central African countries (6.8 million tons), after cassava (28.4 million tons) and maize (13.2 million tons). It ranks 4th in six Southern African countries, and 8th among four in West Africa.
  4. Sweet potato is high in carbohydrates and can produce more edible energy per hectare per day than wheat, rice, or cassava.
  5. Sweet potato requires fewer inputs and less labor than other crops such as maize, and tolerates marginal growing conditions (e.g., dry spells, poor soil).
  6. Many parts are edible. The leaves and tips of the sweet potato plant are widely consumed by people in Africa. Sweet potato vines provide a high-protein animal feed.
  7. Sweet potato is also a valuable source of vitamins B, C, and E, and it contains moderate levels of iron and zinc.
  8. The flesh color of sweetpotato ranges from white, cream, and yellow to orange and purple.
  9. Sweet potato in Sub-Saharan Africa is primarily grown on small plots by poor farmers, mainly women.
  10. Better agronomic practices, such as site selection, planting techniques, spacing, weed control, soil fertility and water management could more than double sweet potato yields in Sub-Saharan Africa.
  11. One of the greatest threats to sweet potato production is sweet potato weevil, which often causes losses of 60-100% especially during droughts.
  12. Sweet potato is bulky and perishable, yet promising pilot efforts are expanding market opportunities through the use of sweet potato flour, dried chips, juice, and bread as well as its use as animal feed. Investments in improved infrastructure and value chain efficiency could expand sweetpotato markets, including into growing urban markets.
  13. Most commonly used varieties in Sub-Saharan Africa are white or yellow-fleshed.  There is a strong emphasis on introducing and promoting orange-fleshed varieties because just one small root (100-125 gms) supplies the daily vitamin A needs for a young child.

Farmers planting sweet potato vines between the cassava in Tanzania

We <3 Sweet Potato

Given the importance of sweet potato in the food consumption in many countries and its nutrition value as well as potential market opportunities, HarvestChoice is closely working together with International Potato Center (CIP; one of the CGIAR Centers) to improved the quality of sweet potato production statistics data, modeling growth and yield of sweet potato in Sub-Saharan Africa, and assessing the potential benefits of introducing new management technologies to smallholder farmers.

More information on sweet potato on the Sweetpotato Knowledge Portal: www.sweetpotatoknowledge.org

Citation

HarvestChoice, 2011. "So You Think You Know Sweet Potato?." International Food Policy Research Institute, Washington, DC., and University of Minnesota, St. Paul, MN. Available online at http://harvestchoice.org/node/1426.
Feb 21, 2011