Identifying a new candidate space crop: the alpine strawberry Fragaria vesca

New food systems are needed for multi-year space missions. Supporting long missions exclusively with preserved food is logistically impractical and would have negative physical and psychological impacts on crew members. One option is to grow crops of fresh food on spacecraft or in off-Earth habitats. Strawberry (Fragaria sp.) has been identified as a potential space crop due to its physical, physiological and sensory properties. We assessed the potential of the alpine strawberry, F. vesca, as a new space crop by comparing F. vesca accession Hawaii 4 (F7) to NASA's space strawberry candidate F. x ananassa 'Delizz'. F. vesca is a diploid strawberry and more readily amenable to genetic optimisation for space than the octoploid F. x ananassa. We grew the two strawberry species in a deep-water culture hydroponic system under conditions that simulated an enclosed space habitat and measured their growth and biomass allocation. We grew both species from seed because seed can be sterilised and stored more easily in space than vegetative plant material. F. vesca was additionally grown from runner plantlets in the system to identify differences between seed and plantlet propagation. Plants were harvested on day 0, 43 and 78 after transplantation into the hydroponic system. Total leaf area, total root length and dry mass of plant tissues were measured. F. vesca showed more promising results when grown from seed compared to runner plantlet. When started from seed, F. vesca accumulated three times more biomass than F. x ananassa 'Delizz' seedlings in the first eight weeks preceding transplant to the hydroponic system on day 0. By day 78 after transplanting, there were no significant differences in total biomass and harvest index between the two strawberry species grown from seed. Seed-grown F. vesca also had a higher specific leaf area by a factor of 1.4 and twice the number of buds, flowers and fruit than F. x ananassa 'Delizz' grown from seed. Despite these favourable traits, the Hawaii 4 (F7) accession of F. vesca appears unsuitable as a space crop in its current form, primarily due to high biomass allocation to runners. Future studies of F. vesca's potential as a space crop should focus on runnerless accessions, propagation from seed, refinement of nutrient concentrations and ambient conditions, and on genetic transformation, to enhance fruit quality, increase fruit yield and optimise root architecture for hydroponics.