Haghighi M., J. France, M.H. Behboudian and T.M. Mills. 2013. Fruit quality responses of ‘Petopride’ processing tomato (Lycopersicon esculentum Mill.) to partial rootzone drying. Journal of Horticultural Science and Biotechnology.(2013) 88 (2) 154–158.
Partial rootzone drying (PRD) is a promising water-saving irrigation strategy for processing tomato, but its effects on fruit quality have not been fully explored.We explored PRD using glasshouse-grown ‘Petopride’ processing tomato.The treatments were (i) fully-watered control (C), or (ii) PRD where half the volume of water given to C was applied to one side of each plant, with the other side being watered next. Plants were irrigated twice a week, when the nonirrigated side of the PRD treatment had dried.The experiment was arranged in a completely randomised design, with six replications of each treatment. Each replication had four plants. Mid-day leaf water potentials were significantly lower in PRD plants than in C plants. PRD fruit matured earlier and had a higher yield than C fruit in the first six harvests. PRD fruit became redder than C fruit, from 3 d after harvest, as judged by their lower hue angle values.Total soluble solids contents and soluble sugars (sucrose, glucose, and fructose) concentrations were higher in PRD-treated fruit. During the first week after harvest, the average rates of ethylene production (in nmol CO2 g–1 s–1 ± SE) were 54.37 ± 8.10 for PRD fruit and 23.59 ± 4.75 for C fruit, respectively. The corresponding values for rates of respiration (in mmol g–1 s–1 ± SE) were 229.29 ± 33.69 for PRD fruit and 109.34 ± 23.21 for C fruit. Fruit weight loss in storage was similar between the two treatments.The values (as a percentage of original weight) were 11.46 ± 1.02% for PRD fruit and 10.53 ± 0.43% for C fruit. The water content of PRD fruit was lower than C fruit, which is an advantage for processing tomatoes.The PRD treatment saved 50% of the irrigation water, while improving many of the fruit quality attributes that are important for processing tomatoes. PRD is therefore confirmed as a feasible irrigation option when growing processing tomatoes.