Survival analysis of freezing stress in the North American native perennial flax, Linum lewisii Pursh

Authors: GOSSWEILER, ANDRE - North Dakota State University; Hulke, Brent; SMART, BRIAN - North Dakota State University

Submitted to: AoBP (Annals of Botany PLANTS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2024
Publication Date: 4/5/2024
Citation: Gossweiler, A.D., Hulke, B.S., Smart, B. 2024. Survival analysis of freezing stress in the North American native perennial flax, Linum lewisii Pursh. AoBP (Annals of Botany PLANTS). 16(3). Article plae022. https://doi.org/10.1093/aobpla/plae022.
DOI: https://doi.org/10.1093/aobpla/plae022

Interpretive Summary: Flax is grown for use in foods and nutritional supplements as a plant-based source of omega-3 fatty acids. Omega-3 fats are required for proper cardiovascular function in humans, but are required in the diet as humans lack the enzymes to generate them. A perennial species of flax, Lewis flax, is a stress-tolerant plant that produces the same omega-3 fats as traditional annual flax but has traits that benefit agriculture, such as deeper roots for water and nutrient uptake and the ability to use the entire growing season. In order to maintain perennial habit, it must be freeze tolerant. In this paper, the authors surveyed available collections of Lewis flax for freezing tolerance using a laboratory based method. Plants with excellent growth rates and survival beyond the lowest observed soil temperatures were discovered, providing excellent materials for breeding Lewis flax for cultivation. This will contribute useful knowledge to the domestication and commercialization of Lewis flax for sustainable agriculture.

Technical Abstract: The expansive range of Lewis flax (Linum lewisii Pursh.), an herbaceous perennial, exposes the species to a diversity of climatic conditions. As interest in the domestication and adoption of perennial crop alternatives grows and interest in this species for natural area restoration continues, the assurance of a commercial plant variety’s ability to endure the full range of possible climatic extremes is paramount. This study examines the freezing tolerance of a geographically representative sampling of 44 Lewis flax accessions at winter temperature extremes experienced in the northern Great Plains of the United States. Survival analysis models were adapted to include temperature exposure, in replacement of ordinal time typically used in such models, to produce statistics evaluating reactions to extreme temperatures that Lewis flax would encounter in our field environments. Our results revealed Lewis flax is more freezing tolerant than previously reported, and revealed four accessions with significantly superior genetic freezing tolerance than the released ‘Maple Grove’ cultivar. Furthermore, regrowth analyses indicate variation among accessions not associated with survival, which could lead to improving regrowth rate and survival simultaneously. These findings and their methodology expand the understanding of Lewis flax adaptation for winter hardiness and offer an efficient, new model that can be used to evaluate freezing tolerance at ordinal temperatures without requiring extensive prior physiological knowledge for a species.