Propagating selected Pinus monophylla accessions by grafting to Pinus edulis seedling rootstocks

Abstract

Single-leaf pinyon pine (Pinus monophylla Torr. & Frém. [Pinaceae]) is a resilient native of the Great Basin and a source of wild-collected, edible pine nuts. It has potential for greater use in sustainable landscaping and as an agroforestry crop on marginal lands. We initiated steps toward identifying superior nut-producing accessions by selecting 6 trees, subjectively based on visible cones on and around the trees, from each of 4 pinyon stands historically used for pine nut collection. Cone production in selected trees was quantified by counting cone abscission scars on 6 branches collected from the top of each tree. Propagation of 3 trees from each stand was undertaken by grafting to seedling double-leaf pinyon pine (Pinus edulis Engelm. [Pinaceae]) rootstocks. Side-wedge and side-veneer grafting techniques were compared by completing 12 replications of each graft for each scion selection. Grafting success was high, and 11 mo after grafting, no significant difference between techniques was seen (91% of the side-wedge and 81% of the side-veneer grafts were successful). Grafted plants were successfully transplanted to an orchard environment as shown by 99% survival after the first field-growing season. Future long-term evaluation of this common garden will provide information toward selecting superior nut-producing trees for northern Utah.