Abstract:

Use of local varieties in cassava gcrmplasm improvement has been intensified in the recent past as farmers demand for
resistant types of their local varieties. This seems to indicate that recently released varieties may be lacking certain
unique characteristics for which farmers selected and maintained the local varieties. During the evolution of the local
varieties, there were hardly any biotic stresses on cassava and therefore, farmers did not consider this in their
selection criteria. As a result, most, if not all local varieties, are susceptible to most of the important diseases and pests
of cassava. Therefore, considerable breeding efforts have centred around improvement of such local cassava varieties
for disease and pest resistance. Sources of resistance have been mainly the Tropical Manihot Series(TMS lines).
Though it has been difficult to get resistant progeny from local cassava female parents, one successful clone yielded
a resistant clone, 95/SE-0087 from a local female parent(Bao) and an improved male parent, TMS60142 (Nasc I). The
clone 95/SE-0087 yields up to 24 tons/ha. It is sweet with good architectural characteristics, a low cyanogenic
potential, good resistance to bacterial blight, cassava green mite and has so far not shown any symptoms of mosaic.