The study aimed to estimate the parameters and the genetic gain in selection of half-sib for nitrogen use efficiency, through simultaneous selection of characters. Two experiments were established, differentiated by nitrogen fertilization, one with proper fertilization (high N) and another in stress conditions (low N). The experiment was using a 10x10 lattice with two replications. In the tests we used 84 different half-sib and 16 witnesses. From the mean squares of analysis of variance in each environment were the estimates of genetic parameters. After the analysis were selected in each environment 17 different half-brothers, through the classical index selection, and verified the repeatability of the progeny in both environments. Observed variability among progenies, determining the potential for population screening for nitrogen use efficiency. The parameter estimates and genetic gains were higher in high N The use of selection index promoted estimates of selection gain of 24.43 and 21.05% for high and low N, respectively, for grain yield. The progenies showed average yield of 13.45 and 19.47% higher than control in high and low N, respectively.
Zea mays L.; recurrent selection; abiotic stress; genetic gain
