Southwest Native American Tribes, such as the Navajo, Hopi, and Pueblo, have grown peaches at least since the early 1600’s, making them a nutritionally and culturally important food source. Historic management practices consisted of reduced irregular irrigation of sandy to sandy loam soils with no fertilizer additions, no pruning, and no fruit thinning. Recent research indicates germinated peach seedlings from seed sourced from a Navajo orchard in Utah are more drought resistant when compared to direct seeded ‘Lovell’ seedlings, and container transplanted ‘Lovell’ seedlings. The purpose of this study was to characterize the Navajo seedlings’ root distribution after direct seeding to better understand their rooting dynamics with regular irrigation and no pruning. All trees were direct seeded in May 2018 and destructively sampled in May 2022. Three trees from each Navajo and ‘Lovell’ treatment were destructively harvested to determine above ground biomass. Root distribution (location relative to the trunk and depth in the soil profile) was determined using a soil core sampling technique. Soil cores were taken in a radial array around the tree, and tree roots (small, medium, large) were separated from the soil cores in the field, before drying and weighing. After the cores were extracted, the remaining root system was excavated, air dried for 10 days, then weighed and photographed. The main effect and interactions of tree type, sampling location, and depth were tested by analysis of variance. The Navajo seedlings had a more extensive root system, including more roots in the grass alleyways, than Lovell seedlings indicating a more competitive root system. There were also qualitative differences in root types between Navajo and ‘Lovell’ in the occurrence of lateral primary roots, sinker roots or fibrous roots. The results of this research will be utilized to determine the Navajo seedlings’ potential for becoming a viable rootstock for the fruit industry.
