The discriminant analysis of main components
(DAPC) that was available in the adegenet package for
R, version 3.0.1 (R Development Core Team 2013) was
used to define the clusters of cassava hybrids and elite
varieties because this technique does not require the
prior definition of genetic groups (Jombart et al., 2010).
Successive clustering with the K-means and the Bayesian
Information Criterion (BIC) method was used to set
the number of groups, where the K with the lowest BIC
value is the most likely element of the data set under
analysis. K values from 1 to 10 were tested, with 10 runs
for each K. After defining the number of groups, the
main component analysis axes that explained more than
80 % of the total variance were retained