Genetic parameters of a progeny trial of Pinus greggii Engelmann ex Parlatore var. australis Donahue & Lopez in the Mixteca Alta of Oaxaca, Mexico

Introduction: The Mixteca Alta of Oaxaca has high environmental degradation. Several species have been planted to recover vegetation cover; Pinus greggii Engelmann ex Parlatore var. australis Donahue & Lopez has grown successfully even without selected material. Objective: To determine growth performance and genetic parameters of 90 families at early ages, for use in the selection of superior trees. Materials and methods: In San Miguel Achiutla, Oaxaca, genetic variation in growth, conformation and straightness of 90 selected open-pollinated families of P. greggii var. australis was evaluated in a progeny trial five years after planting in two different quality sites. Additive genetic variation, heritability (h(2)) and genetic and phenotypic correlations were calculated. Results and discussion: h(2) were superior in the more fertile site. Height, whorls, straightness and volume had greater genetic control (0.09 < h(i)(2) , < 0.18). h(i)(2), of stem straightness was higher when evaluated as a whole than when divided into three sections. Genetic correlations were high and positive among growth variables (r(g) > 0.81; diameter vs. volume = 0.99) and low to moderate for the rest. Volume had a higher genetic correlation with other traits and higher genetic variation and heritability, so it could be used as a selection criterion for breeding cycle. Some genetic correlations differed contrastingly between sites in equal pairs of variables. Conclusion: Differences between families and heritability will allow the identification of superior individuals for germplasm sources for regional use.