Vacancy Information

PhD Studentship: Interaction between light intensity and rootzone water deficit stress to improve strawberry nutrient content


Location: Kent
Closing date: 17 Jun 2022
Reference number: CTP_FCR-2022_3

Job details

Exploring the interaction between light intensity and rootzone water deficit stress as a means of improving berry phytonutrient content and Class 1 strawberry yields in TCEA systems

Mark Else (NIAB EMR), Paul Hadley and Carrie Twitchen (University of Reading)

Total environment-controlled agriculture (TCEA) systems offer great potential for a consistent supply of high quality and phytonutritious strawberries, provided that initial plant quality is high and growing conditions are fully optimised. However, this is often not the case. Although diurnal temperatures, photoperiods, light intensities, and wavelengths can all be controlled precisely, the optimum growing conditions for proprietary strawberry varieties are not known, and so Class 1 yields are significantly lower than anticipated in many TCEA systems. High relative humidifies often arise due to the constant high evaporative demand and imprecise irrigation scheduling, and so the energy costs associated with maintaining RH in the optimum range are often high.
Our previous work at East Malling showed that regulated deficit and transient deficit irrigation techniques could be used to improve resource use efficiency (light, water, fertiliser) and improve berry phytonutrient content whilst maintaining good commercial yields. The effect of a deficit-induced burst of ethylene production on antioxidant accumulation in non-climacteric strawberry fruit was also explored, and the work suggested that an interaction between light intensity and rootzone water deficits was more likely to raise berry phytonutrient content than either treatment alone.
This PhD programme will investigate the role of hydraulic and chemical signals in the regulation of strawberry responses to targeted rootzone water deficits, and this knowledge will be used to inform, develop, and test new growing protocols for TCEA systems that incorporate beneficial stresses to improve resource use efficiency, marketable yields, and berry quality.   The lighting environment (intensity, wavelength, photoperiod) will be manipulated to maximise photosynthesis throughout the light period in TCEA systems, and to accommodate the diurnal decline in photosynthetic efficiency measured in strawberry. Sensor technologies will be deployed to monitor and control the growing environment, and to measure root, leaf, and fruit responses to applied treatments in real-time. Outputs from this plant environmental science-based CTP PhD study will include innovative growing protocols for proprietary strawberry varieties, and the resulting blueprints will help to inform commercial strawberry production in TCEA systems.