Results
The phenotypic data collected at seedling, clonal and
preliminary evaluation stages showed variation typical
of a quantitative trait for fresh root yield at 7 MAP
among the genotypes in each population (Table 3).
There was reduction in the number of individuals used
at subsequent stages of the phenotypic evaluation of
the progeny in the nine families (Table 4). This was
due to poor vigour of some progeny which made it
impossible to get enough planting materials for further
evaluation. It was even difficult to get just a plantable
cutting from the stems of some progeny and this was
observed in all the nine populations. Cassava is highly
heterozygous; the poor vigour observed in some
progeny may therefore be consequence of inbreeding
depression.
The number of individuals used for genetic analysis
ranged between 42 and 123 per population and about
7–20 genotypes were used to form the contrasting