Variation and heritability in height, diameter and volume of Pinus patula in an asexual seed orchard in Huayacocotla, Veracruz Mexico.

Pinus patula seeds are in high demand for the establishment of plantations in Mexico and around the world because of the fast growth of this species. However, genetically improved germplasm of forest species is scarce in Mexico. For this reason, in 2012, the Mexican government started a program of asexual seed orchards with species of the Pinus genus to meet the germplasm demand. Thus, the objectives of the present research were: to evaluate the height, diameter at breast height, and volume of Pinus patula clones in an asexual seed orchard and to estimate the heritability of these traits. The asexual seed orchard was established in 2012. The diameter at breast height and total height (DBH) were measured and the volume of each ramet was calculated. Subsequently, clonal heritability was estimated for each trait in the four-year-age clones. Differences were found among clones. The average height was 4.38 m, and it varied from 3.39 to 4.80 m for the clones 103 and 28, respectively. The average DBH was 5.46 cm and varied from 3.98 to 6.52 cm for clones 103 and 25, respectively. The average volume was 6.23 dm3 showing a range from 2.62 to 9.53 dm3 for clones 103 and 25, respectively. Clones of Pinus patula had high values of height, DBH, and volume. Heritability values for height, DBH and volume were 0.655, 0.508 and 0.575, respectively. Thus, these traits show high heritability, in other words, they are influenced by genetic component.