Genotype x Environment interaction, stability, and adaptability in progenies of Eucalyptus urophylla S.T. BLAKE using the AMMI model

One of the determinant factors in the success of breeding pro­grams that aim to select genotypes for different geographical regions is understanding the interaction between genotypes and environments (GxE). The objectives of this study were to evaluate GxE interaction, stability, and adaptability, and deter­mine the need for environmental stratification of open pollina­ted progenies of Eucalyptus urophylla. Five progeny tests were established in study areas with different environmental condi­tions in southeast and mid-west Brazil. We used a complete randomized block experimental design with 138 to 167 proge­nies, and variations in the numbers of replicates and plants per plot. The trait measured was diameter at breast height (DBH) at two years of age and the AMMI method was used to determine patterns of GxE interaction. Significant effects were detected for genotypes, environments, and for GxE interaction. The effect of environment was responsible for the greatest propor­tion of the phenotypic variation, followed by the effect of genotypes and GxE interaction. Some progenies with greater productivity and stability were identified, although stability is not associated with productivity. The stratification of the selec­tion in three specific environments is necessary due to the occurrence of a complex GxE interaction.