Breeding perennial flax for ornamental and agronomic traits simultaneously during crop domestication increases the efficiency of selection

Floriculture breeders select elite genotypes with proven stability in performance over years and locations, allowing for global distribution of ornamental cultivars. In contrast, agronomic crops are bred for latitude-specific cultivation. The University of Minnesota flower breeding program for perennial flax, in partnership with the Forever Green Initiative, implements domestication, breeding and selection for wide adaptation of both ornamental and agronomic traits. Perennial flax (Linum perenne, L. lewisii, L. austriacum) possess a wide range of traits for both the floriculture (cut flowers, garden) and agronomic (oilseed, fiber) markets as well as corollary ecosystem services (pollinators). The objectives of this study were to demonstrate the innovation and efficiency of integrated breeding of perennial flax using multiple crop ideotypes. A total of 37 wild flax species (150 accessions) and 11 advanced populations were evaluated in 2021-2 for selection frequency of trait expression, % rooting, and seed yield. Traits selected were ornamental – cut flower (CF), floral markings (FLM), floriferousness (FL), garden (G), groundcover (GC), holding potential (HP), lodging resistance (LR), pollinators (P), white flowers (WHT); agronomic – oilseed (OS), fiber (F), regrowth potential (R). Selection frequencies demonstrated that, in wild species, 7 trait combinations (CF, FL, FLM, G, HP, OS, R) in 32/200 genotypes (16%) in 18 populations, while in advanced selections, 9 trait combinations (CF, FL, FLM, G, HP, LR, OS, R, WHT) in 66/220 genotypes (30%) in 11 populations are selectable. There was a similar likelihood that 7 agronomic/horticultural traits in both wild and selected populations could be simultaneously selected with similar frequency. For most selected traits, wild (2.4-87.3%) vs. selected (9.6-98.4%) genotypes had statistically similar rooting in paired comparisons, except for G, which differed significantly among wild species (9.6%) and selections (84.1%). Linum austriacum exhibits the greatest potential for domestication, based on summer/winter survival. Thus, it is feasible to simultaneously select for both agronomic and ornamental traits to make gains from selection.