Predicted genetic gains for growth traits and Genotype x Environment interaction in Pinus greggii: new perspectives for genetic improvement in Brazil.

Pinus greggii has potential for inclusion in temperate zone breeding programs around the world as it is frost resistant and produces high yields for pulp production. This study estimates the genetic parameters for two P. greggii progeny tests established in Telêmaco Borba, Paraná, Brazil. We evaluated diameter at breast height (DBH) and total height (H) at seven and nine years of age. The narrow-sense heritability ( h i 2 ) ranged from 0.225 (H, 7 years) to 0.515 (H, 9 years). The genetic correlation was high for all traits, reaching up to 0.91 between traits and 0.94 between ages. In addition, the results show the presence of Genotype x Environment interaction, and as such, the most productive and stable progeny were identified based on the Harmonic Mean of the Relative Performance of Genetic Values (MHPRVG) values. These population has genetic materials that are superior in terms of both DBH and H compared to the control and to P. greggii materials analyzed internationally. Our results contribute to the literature by providing further genetic information on this species, while also demonstrating the implications of thinning for genetic gains and effective population size.