Résumé
The intra- and interpopulation genetic variability was studied in 2 forage maize populations at Co and C1 cycles of selection, from nested mating designs. The following traits were studied: flowering earliness, plant and ear heights, length and width of ear leaf, whole-plant yield and dry matter content. The nature of genetic variance was the same in intrapopulation and in interpopulation progenies: for yield and length of ear leaf, the dominance variance was significant; for the other traits, the additive variance explained most of the genetic variability. The intrapopulation and interpopulation additive variances were similar for highly heritable traits (heights and earliness) and were quite different for yield. The male plant average effects, estimated in intrapopulation and in interpopulation, were related: correlations were positive for all traits, lower for low heritable traits. Results were consistent with those reviewed from different selection experiments. Conclusions for breeding methods were then suggested.