Roots and tubers refer to any growing plant that stores edible material in subterranean root,
corm and tuber (Shajeela et al., 2011).They are the most important food crops in the tropics
and subtropics (Behera et al., 2009). Cassava, sweet potato, potato and yam are grown in
varied agroecologies and production systems contributing more than 240 million tons
annually, covering around 23 million hectares. The aggregate value of yam, cassava, potato
and sweet potato exceeds all other African staples, including cereal crops
(NteranyaSanginga, IITA, 2015).
The four crops have common and unique challenges related to quality of seed production,
new variety adoption, losses due to insects and diseases, low productivity in poor soils,
tolerance to stress associated with heat and drought, consumer preferences, and storage of
harvested products (NteranyaSanginga, IITA, 2015).