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A suitable design should control the environmental effect and be capable to discriminate the genotypes. Two clonal tests of Eucalyptus were planted side by side in a randomized block design with the same 32 treatments under two different plot designs. The first trial was designed in five plants per plot (linear plot – LP) within six block replicates at spacing 3 x 2 m. The second trial was designed in one plant per plot (single tree plot – STP) within 30 block replicates also at spacing 3 x 2 m. Diameter at breast height, height and individual volume were measured at five years of age. The STP design presented broad sense heritabilites ranging from 0.23 to height from 0.41 to volume, which were higher than those found for the LP design (0.12 to height from 0.22 to volume). The ratio between the estimated the genotypic variance and its standard error () were lower for the three evaluated traits in the STP. The correlations between the genetic values were positive and of high magnitude, ranging from 0.87 to height from 0.91 to volume. The STP presented better discriminant power according to the biplot analysis, as well as more accurate and reliable estimates.