COMBINATION ABILITY OF TROPICAL MAIZE POPULATIONS UNDER LOW NITROGEN STRESS

The aim of this study was to determine the combination capacity among populations, to identify germoplasm fonts of tropical maize populations and, to define strategies to maize breeding under low nitrogen stress (N). Two germoplasm fonts of maize were used (elite cultivars and local open pollinated populations) in a complete randomized block scheme, with two replicates. It one was obtained with low nitrogen fertilizer only in the sowing. The general combination abilities (GCA), that evaluated additive effects, were significatives to height of plants and ears to elite cultivars and to grain yield, ear yield, and height of ears to local populations. The specific combination abilities, that evaluated non-additive effects, were not significative to every trait. So, we conclude that to tropical maize populations evaluated in the low nitrogen the general combination capacity is the main effect to traits; It is possible to make new populations with local populations and use intrapopulation methods; the populations Caiano de Sobralia and Nitrodente in hybrids combinations with elite cultivars were adequate germoplasm to increase the grain yield with short plants and ears; the hybrids combinations between local populations and elite cultivars are not adequate to obtain hybrids.