| Summary: | In Chile, interspecific hybrids between <i>Eucalyptus nitens</i> × <i>Eucalyptus globulus</i> (GloNi) were developed by Arauco Forestry to capture specific traits from each parental species: growth rate and cold resistance from <i>E. nitens</i> (NIT) and wood properties from <i>E. globulus</i> (GLO). Field tests of <i>E. nitens</i> × <i>E. globulus</i> were distributed in two geographic zones: Arauco (12 tests) and Valdivia (15 tests), where growth and wood properties measurements were recorded at different ages. The hybrid population is composed of clones from 28 full-sib families, being the result of crossing 12 <i>E. nitens</i> females and 8 <i>E. globulus</i> males. Progeny from each of these families were vegetatively propagated and tested on each growth zone, with a total of 1214 clones developed. The quantitative genetic parameter estimates reveal high genetic variation in hybrid volume gain and wood properties, which make possible large genetic gain in all traits analyzed. Additionally, <i>E. nitens</i> has a considerable impact on the volume gain of the hybrid, making it important to test more parents in future interspecific crosses in both hybrid zones. In contrast, <i>E. globulus</i> demonstrated zero impact in volume. In wood traits, <i>E. globulus</i> in Arauco zone demonstrates a large effect on the genetic variability of these traits; meanwhile, in the Valdivia zone, <i>E. nitens</i> and <i>E. globulus</i> parents contributed roughly similar amounts of genetic variation. The high General Hybridizing Ability (GHA) and General Combining Ability (GCA) relationship between hybrid progeny and pure species progeny performance indicates that parents could be selected for interspecific crosses based on pure species test results for volume and wood properties.
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