ASSESSMENT OF THE EARLY SELECTION EFFICIENCY IN EUCALYPTUS CLOEZIANA MUELL,F IN THE NORTHWEST OF MINAS-GERAIS STATE (BRAZIL)

Three hundred and seventeen half-sib progenies of Eucalyptus cloeziana F. MUELL. of 8 different origins in the northwest of the state of Min as Gerais, Brazil were assessed far early selection efficiency. The ex periment was carried out in the county of Bocaiuva in 1987, using the compact progenies block design with 10 replications and 6 plants per p lot. The stem diameter at breast height (DBH) was taken at 29, 42, 56, 67 and 80 months of plant age. The estimates of the genetic and pheno typic parameters for the DBH trait were obtained for each age and for the combination of ages. The trait genetic correlations at the differe nt ages and the correlated response to selection were also estimated. The methodologies used in the assessment of the early selection effici ency demonstrated that this strategy should be used in Eucalyptus bree ding. The selection done at the age of 29 months proved to be more eff icient, propitiating a superior gain per unit of time, compared to any other of the selection strategies.