[Analysis of genetic effects for growth traits of Eucalyptus globulus Labill. in a 6 x 6 diallel design].

The genetic effects of general and specific combining ability, male, female, and specific reciprocal cross were estimated for height, diameter of breast height (dbh), volume, crown-width, under branch height, crook degree and ratio of branch with shoot in Eucalyptus globulus Labill. Three quantitative characters, i.e. tree height, dbh, volume were focused, and their effects were discussed in detail. It was found that the GCA, SCA and specific reciprocal cross effects (SRE) were most important, and female effect (FEM) and male effect (MAL) were less important. Three parents with high GCA were good materials used for establishing seed orchard. Eight combinations significantly improved quantitative characters. One of them was improved on quantitative character and trunk quality at the same time. The breeding strategy and methods were also suggested for E. globulus.