Traumatic ducts size varies genetically and is positively associated to resin yield of Pinus oocarpa open-pollinated progenies

Abstract

Mexico ranks 5th in worldwide resin production. Pinus oocarpa is the most widely tapped pine tree in Mexico. Michoacán (central-western Mexico) is the first nationwide state producer of resin. Despite the P. oocarpa relevance, there is no genetic improvement program in the country for resin production. We evaluated the degree of genetic control for growth, anatomical traits, resin yield, and the correlation among them at an early age (five-years-old for growth, six for resin, and anatomical traits) in a P. oocarpa half-sib progeny trial. Families were originated from selected mother trees, based on their resin yield. We found significant genetic variation among families for stem volume (h 2 i = 0.12, h 2 f = 0.35), traumatic ducts (diameter: h 2 i = 0.63, h 2 f = 0.51; area: h 2 f = 0.81), and resin yield (individual and family narrow-sense heritability: h 2 i = 0.20, h 2 f = 0.52), and a positive correlation between diameter and area of traumatic ducts with resin yield (Pearson correlation: r= 0.73, p= 0.04; r= 0.71, p= 0.0497; respectively). Results suggest that the early selection (six-years-old) of superior P. oocarpa families, based on resin yield (estimated by microchipping technique), and/or based on larger diameter and area of traumatic ducts, appears to be a feasible strategy to develop seed orchards able to provide genetically improved seeds for intensive resin tree plantations. That would be an important alternative for a state as Michoacán, Mexico, where natural P. oocarpa stands are being replaced for avocado orchards for exportation.

Abundance of Dendroctonus frontalis and D. mexicanus (Coleoptera: Scolytinae) along altitudinal transects in Mexico: Implications of climatic change for forest conservation

“…On the other elevational extreme, transects at Chiapas state covers a pine forest dominated by P . oocarpa , that neighbor with tropical dry forest, and is also the most important resin producer in México [ 58 ]. Pinus leiophylla , a pine widely used also as resin producer [ 59 ], is also covered on transects at Durango.…”

“…The transects cover the two pine species that conform the extremes of the pine and pine oak forest in Me ´xico: The transects at Sierra de Arteaga, Coahuila state, includes pine forests dominated by Pinus hartwegii, a high altitude pine that conforms the timberline at Me ´xico, that reach 4,000 m of altitude and dominate several Natural Protected Areas on the highest mountains of Me ´xico [57]. On the other elevational extreme, transects at Chiapas state covers a pine forest dominated by P. oocarpa, that neighbor with tropical dry forest, and is also the most important resin producer in Me ´xico [58]. Pinus leiophylla, a pine widely used also as resin producer [59], is also covered on transects at Durango.…”