Estimates of genetic parameters among and within Half-sib families in two selection cycles on the EEL2 maize (Zea mays L.) population

Abstract

Two cycles of selection among and within half-sib families were evaluated on the maize population EEL_2, from 1987 to 1989 in the north, south and highland of Espírito Santo State, Brazil, in order to estimate the efficiency of selection for the trait ear weight. Two hundred half-sib families, were evaluated in each cycle, using two latices 10 x 10, with two replications per location. For the cross over, the selection rates of 15% among progenies, and 12.5% within progenies was used. For the trait ear weight, the analysis of variance individual and combined, detected significant differerices for progenies and for the interaction of progenies x locations. The additive genetic variance values varied for locations and cycles, ranging from 501.4 to 1002.7 (g/plant)². The values of those variances at combined analysis were smaller than the values of individual analysis: 58.0 (g/plant)² for the first cycle and 292.7 (g/plant)² for the second cycle. Mean expected gains were 1.5% and 8.2% at first and second cycles, respectively. The magnitude of those estimations, the high values of heritability and of genetic variation coefficients, associated to the high means of progenies productivity, indicate the high potential of this population in a breeding program.