Genetic Parameters and Family Selection of Pinus pseudostrobus var. apulcensis Through Growth and Stem Quality in Mixteca Oaxaqueña Region, Mexico

The Mixteca Oaxaqueña region has historically suffered from soil and vegetation loss. However, since the last decade of the previous century, successful reforestation efforts have been carried out in many areas. As a result, there is now a need to select phenotypes with superior growth and good wood quality. This study aimed to estimate genetic parameters and identify superior families of Apulco pine (Pinus pseudostrobus var. apulcensis (Lindl.) Shaw) based on growth and stem quality traits. After four years, growth and stem quality traits were evaluated in 64 open-pollinated families. Different selection intensities were tested using two evaluation methods. All traits showed significant differences among families (p ≤ 0.0016), with genetic coefficients of variation ranging from 8.01% to 18.84%. Heritability estimates for growth traits were high (hi2 = 0.42−0.66; hf2 = 0.55−0.63), whereas heritability for stem quality traits was slightly lower (hi2 = 0.01−0.38; hf2 = 0.01−0.38). Genetic correlations (rg) among growth traits were high and positive (rg ≥ 0.857), while correlations among stem quality traits and between quality and growth traits were more variable (r9 = −0.498 to 0.899). Based on both evaluation methods and a 25% selection intensity, sixteen superior families were identified, showing estimated genetic gains of approximately 4% for growth-related traits. These families are recommended for use in timber plantations, whereas a broader set is suggested for reforestation efforts in order to maintain genetic diversity.