Effect of water deficit irrigation on strawberry (Fragaria × ananassa) fruit quality.

Growers are under increasing pressure to demonstrate that their water abstractions for irrigation are reasonable, justified and environmentally sustainable. Deficit irrigation (DI) is one means of reducing water usage. However, many authors have shown that DI can reduce berry size and yield in strawberry plants. The present study demonstrated that whilst DI did detrimentally affect berry size, it had a profound influence on both fruit physiology and biochemistry. Dry matter content as a proportion of fresh weight was increased by a quarter in both primary and secondary position fruit (primary truss) from water-stressed plants as compared to fruit harvested from plants held at or near field capacity. Strawberry 'Elsanta' fruit from plants that received less water had higher levels of abscisic acid (ABA). Concomitant to this, the concentration of some taste-related (viz. monosaccharides and sugar:acid ratios) and health-related compounds/parameters (viz. antioxidant capacity and total phenolics) were generally much greater in DI-treated fruit. Glucose and fructose concentrations were 1.2-fold higher in DI-treated as compared to non-drought-stressed fruit. Similarly, total phenolics were up to 1.4-fold higher in fruit from DI-treated plants. The effect of inoculation at anthesis with Botrytis cinerea on ripe fruit was also tested. Fruit derived from inoculated plants displayed symptoms of grey mould postharvest disease earlier than non-inoculated fruit, and had double the concentration of ABA. Inoculation had no significant effect on any other target analytes measured. There was no interaction between water treatment and inoculation.