Water Relations, Growth, and Yield of Processing Tomatoes Under Partial Rootzone Drying

ABSTRACT Water for irrigation is limited worldwide. Therefore water saving practices will have to be adopted. This experiment was carried out to compare deficit irrigation (DI) with partial rootzone drying (PRD) for their effects on the processing tomato (Lycopersicon esculentum Mill.) cv. Petopride. The treatments were: full watering of both sides of the root system (RS) at each irrigation as control (C), half of irrigation water in C divided equally to both sides of the RS with each watering (DI), and half of irrigation water in C given only to one side of the RS with each irrigation (PRD). Photosynthetic rate, transpiration, stomatal conductance, and leaf water potential were measured on five occasions, and were found to be the same among treatments. Total fruit fresh mass was lower in DI and PRD than in C, but total fruit dry mass was the same among treatments. Irrigation use efficiency was higher in DI and PRD than in C. Vegetative fresh mass was not affected by treatment. However, compared with C plants, vegetative dry mass was higher in DI and PRD plants. Percentage of dry mass allocated into roots was the same among treatments, but a higher allocation was into stems and leaves in DI and PRD plants than in C plants. This was the opposite for the fruit. Total fruit fresh mass was affected by the quantity of irrigation water applied, but not by the volume of soil wetted. Both DI and PRD treatments were found to be feasible water-saving practices for ‘Petopride’.