Effect of environmental variability on fruit quality and phytochemical content of soilless grown tomato cultivars in a non-temperature-controlled high tunnel

Abstract

The present study investigated the influence of environmental conditions (growing regions and/or fruit-harvesting periods) and cultivar on fruit phytochemical content and quality parameters of “salad-type” fresh market tomatoes grown in protected soilless culture under non-temperature-controlled high tunnels. Sixteen high yielding hybrid tomato cultivars of indeterminate growth were grown in three different regions (Tshwane, Eastern and Western regions) of a subtropical highland climate, and the fruits were harvested in three different periods of the growing season for fruit quality analysis. The Eastern region was in general the most ideal environment for increased fruit quality (particularly fruit electrical conductivity) and phytochemical content of soilless grown tomato cultivars in a non-temperature-controlled high tunnel. The fruit electrical conductivity was considerably high in this region, irrespective of its harvesting period. The potential to maximize a certain type of phytochemical or fruit quality parameter was cultivar-dependant. Cultivars responded differently to the changing environment. However, the fruit total soluble solids level of those cultivars showing superior performance was positively influenced by increased levels of thermal time accumulation and minimum relative humidity, while their fruit electrical conductivity level was reduced with increased vapour pressure deficit. On the contrary, the fruit pH level did not seem to be affected by the environment or cultivar type. Therefore, identifying appropriate growing environments for the tomato cultivars is crucial for improved phytochemical content and fruit quality parameters, contributing to nutrition security, improved income generation for farmers and overall societal well-being.