Does water stress improve fruit quality in open field grown strawberry ?

Strawberry (Fragaria x ananassa) yield is known to be sensitive to water stress. Even in the Belgian temperate climate irrigation is a necessity to ensure maximal yield in open field grown strawberry. Recent research, mainly in greenhouse experiments, shows how sugar/acid ratio and total soluble solids (TSS) are positively affected at a lower irrigation level (e.g. Borbonada and Terry, 2010)1. In 2015 and 2016 irrigation experiments were set up in two research locations in Belgium to test the effect of water stress on strawberry quality. One experiment was set up with a June-bearing variety and the other one with an everbearing variety. Two different irrigation regimes were applied in a randomized experiment with four replications. Discussion Strawberry is affected by water stress as shown by the relation between Ψplant and TSS and fruit firmness. Lower Ψplant was linked to higher TSS, confirming previous findings1 in a greenhouse. The observed relationship between fruit firmness and water stress was less straightforward since relation was only observed in Sint-Truiden and not in Meerle. Furthermore relationship was positive in June-bearing Elsanta in 2016 but negative for everbearing Portola in 2016. In general relation between Ψplant and TSS, fruit firmness was weak with R² hardly exceeding 0.5, only on a part of the harvest dates. These findings are arguments to irrigate with care. However deliberately inducing low Ψplant by deficit irrigation poses risks since total yield can be affected, as in Sint-Truiden in 2015.