Multivariate approach in eucalyptus breeding and its effecton genotype x environment interactions

In view of the need to obtain genetically superior eucalyptus clones that promote productivity coupled with quality, we used multivariate statistical techniques for the selection and evaluation of Eucalyptus spp. clones for wood production. The experiments were carried out in three environments in the districts of Eldorado do Sul, Butiá and São Gabriel. A clone of the commercial species Eucalyptus saligna was used as a common control in all trials. A total of 84 eucalyptus clones were used belonging to the breeding program in Rio Grande do Sul, Brazil, in a randomized block design, with 20 replicates and one plant per plot, spacing 3.50 x 2.14 m. Silvicultural practices were performed according to the particularities required by each environment. The clones were evaluated at 36 months for diameter at breast height, total height, total individual volume with bark and survival of clones. The datawere submitted to a joint analysis of variance, and the significance was interpreted by the F test at 5% probability. Interaction tests were performed and then multivariate models were used. Selection of clones from their values of genetic divergence and heterogeneity in relation to the others can be used to increase variability in breeding populations. Improvement strategies such as Intrapopulation Recurrent Selection can be "fed" from selections made based on these parameters, but also focusing on increasing productivity and improving wood technology. There wasa great difference in behavior of the clones for each environment, demonstrating the influence of genotype x environment interactions, which can be evaluated later in amplified clonal tests or in the observation plantings of these clones; these will serve for the future indication of genotypes for commercial plantations.