Item Details

Title: Review of sweetpotato seed systems in East and Southern Africa

Date Published: 2009
Author/s: R. Gibson, R.O.M. Mwanga, S. Namanda, S.C. Jeremiah, I. Barker
Data publication:
Funding Agency : Bill and Melinda Gates Foundation
Copyright/patents/trade marks: International Potato Center (CIP)
Journal Publisher: International Potato Center (CIP)
Affiliation: Natural Resources Institute, University of Greenwich, National Crop Resources Research Institute, International Potato Center, Lake Zone Agricultural Research and Development Institute


The sweetpotato crop in much of Africa, including East Africa, is largely grown by women in
smallholder farming households; its seed systems are, similarly, predominantly in the informal
sector and women seem important though their roles are inadequately researched. The crop, as
elsewhere in the world, is propagated primarily from foliar cuttings. In equatorial regions where
there is bimodal rainfall and the crop is grown throughout the year, these can easily be obtained
from existing mature crops and this region is where the crop is mostly grown. Although there are
few issues regarding planting material availability or even price as it is mostly free, improvements
are needed in quality of the planting material, particularly:
? the range of good varieties (both for all-round better varieties; varieties with specific
attributes, such as orange-fleshed to broaden the market and an emphasis on participatory
? freedom from weevils
? sweetpotato virus disease (SPVD), and
? physiological vigor.
However, even just a few degrees north or south of the Equator, the increasing unimodality of the
rains leads to long dry seasons during which sweetpotato cannot survive as an actively growing
plant. Although the above issues remain, the overwhelming constraint is lack of planting material at
the beginning of the rains, leading to late planting and limited areas planted. The latter leads to the
crop failing to fulfill its potential to be the first major food crop to be harvested, to fill the ‘hungry
gap’ when granaries are empty and to realize high sales and prices. This lack of planting material is
the main reason why the crop is grown so much less away from the Equator, further impoverishing
some of the poorest people in Africa such as in Ethiopia, Sudan and other Sahelian countries,
Mozambique, Zimbabwe, Malawi etc. T