One of the most important phases in commercial maize breeding programs is the
assessment of the value of newly-developed progeny by testing in hybrid
combinations. In this study, non-parametric stability measures were applied
to analyze the genotype ? environment interaction and to assess phenotypic
stability of two half-sib maize populations, each consisting of 40
genotypes, across 9 variable environments. Non-parametric tests of
significance determined the presence of qualitative interaction for grain
yield in both observed populations. Results of the stability analysis showed
no significant differences between the two progeny groups indicating that
the used testers did not bring significant increase in stability in either
of the analyzed half-sib populations. Individual genotypes were also
compared based on grain yield stability within both progeny groups using the
stability parameters Si(1), Si(2), Si(3) and Si(6). Association between the
grain yield and stability indices Si(1) and Si(2) of the analyzed genotypes
was presented graphically enabling the identification of genotypes which can
be recommended for further breeding process as the most promising ones. The
correlations between grain yield and stability parameters were tested by
Spearman?s rank correlations. Both progeny groups (HS1 and HS2) showed no
significant correlations between the grain yield and stability parameters
Si(1) and Si(2), but the rank correlations between Si(1) and Si(2) values
were very strong and highly significant. Highly significant negative
correlations were found between grain yield and stability indices Si(3) and
Si(6) in both progeny groups, and very strong and highly significant
correlations were found between Si(3) and Si(6) values.