Combined Effects of the Training Method and Deficit Irrigation on the Yield and Fruit Quality of Semi-Determinate Cherry Tomato (<i>Solanum lycopersicum</i> L.)

Abstract

Deficit irrigation can be used to improve tomato fruit quality. The semi-determinate tomato behaves like a bush tomato, with lateral shoots providing additional vegetative growth, but the response to deficit irrigation and the suitable training method have not been properly understood. Therefore, we clarify the combined effect of a training method (non-training, which omits manual plant management such as lateral shoot removal) and deficit irrigation (30–36% of field capacity) on yield, growth, and fruit quality of semi-determinate cherry tomato. Although deficit irrigation influenced non-training plants more than single-training plants (a conventional method by removing all lateral shoots) owing to the lowest midday leaf water potential, both plants showed the same levels of maximum quantum efficiency of photosystem II and fruit yield under deficit irrigation. Furthermore, non-training plants produced the highest levels of total soluble solids, glucose, fructose, citric acid, malic acid, and ascorbic acid under deficit irrigation. These observations indicated that the increased concentrations of the abovementioned components occurred as a result of water shortage in the fruit when compared with single-training plants. We conclude that non-training is suitable for semi-determinate cherry tomato cultivation under deficit irrigation, and that this method can produce high-quality fruits while mitigating manual plant management.