Assessment of biogeographic variation in traits of Lewis flax (Linum lewisii) for use in restoration and agriculture

Authors: INNES, PETER - University Of Colorado; GOSSWEILER, ANDRE - North Dakota State University; JENSEN, SCOTT - Us Forest Service (FS); TILLEY, DEREK - Natural Resources Conservation Service (NRCS, USDA); ST. JOHN, LOREN - Natural Resources Conservation Service (NRCS, USDA); Hulke, Brent; KITCHEN, STANELY - Us Forest Service (FS); Jones, Thomas

Submitted to: AoBP (Annals of Botany PLANTS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2022
Publication Date: 2/4/2022
Citation: Innes, P., Gossweiler, A., Jensen, S., Tilley, D., St. John, L., Jones, T.A., Kitchen, S.G., Hulke, B.S. 2022. Assessment of biogeographic variation in traits of Lewis flax (Linum lewisii) for use in restoration and agriculture. AoBP (Annals of Botany PLANTS). 14(2). Article plac005. https://doi.org/10.1093/aobpla/plac005.
DOI: https://doi.org/10.1093/aobpla/plac005

Interpretive Summary: Flax is grown worldwide as a food and fiber crop, and is a short-lived annual. In the United States and Canada, there exists a native perennial relative, Lewis flax, found in western pine forests from about 2,000 to 11,000 feet in elevation above sea level. The USDA Forest Service, Natural Resources Conservation Service, and Agricultural Research Service, in collaboration with University of Colorado and North Dakota State University, have collected Lewis flax from the Intermountain West and observed the collections in common garden trials in two sites in Utah for plant-growth-related traits. Seed samples were analyzed for their usefulness as a human-consumable vegetable oil. The results show a great amount of variation among collections for plant and seed traits. These results will facilitate the domestication of Lewis flax as a high-omega-3 vegetable oil source for human consumption, as well as seed increase of Lewis flax for native plant restoration of disturbed lands in the American West.

Technical Abstract: Lewis flax (Linum lewisii) is widely distributed across western North America and is currently used in native ecosystem restoration. There is also growing interest in de novo domestication of Lewis flax as a perennial oilseed crop. To better understand this species and facilitate both restoration and domestication, we used common gardens to assess bio-geographical variation in a variety of seed and growth traits from 37 flax accessions, consisting of 35 wild populations from the Intermountain west region of the United States and two cultivars, and related it to collection site geography and climate. Results from linear mixed models suggest there is extensive, genetically-based trait variation among populations of Lewis flax within the Intermountain west, which is a fraction of its complete range. Using a multivariate approach, we identify a key suite of traits, including flowering indeterminacy, seed size, stem number, that are related to latitude and climate and may facilitate adaptation. These traits should be taken into account when considering the release of new germplasm for revegetation purposes. We also find that Lewis flax seed contains desirably high amounts of alpha-linolenic acid and is otherwise mostly indistinguishable in fatty acid composition compared to oil-type varieties of cultivated flax (L. usitatissium); this provides an excellent starting point for oilseed breeding. Overall, this study provides fundamental knowledge for future research into the ecology and evolution of Lewis flax, which will inform its use in both restoration and agriculture.