Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Committee Chair(s)

Larry Rupp


Larry Rupp


Michael Kuhns


Teryl Roper


Single-leaf pinyon pines are drought tolerant trees native to the Great Basin. This species is a source of wild-collected, edible pine nuts that are in great demand. With no previous research apparent, this thesis aimed to identify wild trees with high cone production as sources for evaluating grafting onto immature and mature trees. Wild sources of scions were identified from four wild stands and six trees per stand. Counting and analyzing the number of scars left by mature cones along the leader branch provided an estimate for each tree’s productivity and identified trees with greater productivity within a stand. The three best trees in each stand were selected as a scion source grafting on the estimated cone production and health of the new growth of each tree. Scions from each selected single-leaf pinyon tree were grafted onto two-leaf pinyon seedling root stocks using two graft types. After one year, survival rates were above 80% with no difference between graft types. Grafting onto mature trees with treatments including scion treatments, timing of grafting event, and graft type were evaluated in 2017. The treatments with the highest survival rates were scions with needles, spring timing of grafting, and side-wedge graft type. In 2018 and 2019, further graft evaluations were done to compare graft types with final evaluations on March 11, 2020 (2019 grafts had survival rates over 67%).