RESPONSE OF TOMATO TO PARTIAL ROOTZONE DRYING AND DEFICIT IRRIGATION

Abstract

Water is a limiting factor for plant production worldwide, and therefore it is necessary to adopt water saving irrigation practices. Partial rootzone drying (PRD) is a new water saving irrigation techique, which was compared with deficit irrigation (DI). The effects of PRD and DI on leaf water potential, plant growth, biomass allocation, yield, and fruit quality of ‘Petopride’ processing tomato (Lycopersicon esculentum Mill.) were studied. The treatments were: daily full irrigation (FI) on both sides of the root system (RS) considered as control; irrigation on one side of the RS with half the volume of water given to controls where the irrigation was shifted over from the wetted part to the drying part of the RS every day (PRD); and full irrigation every other day on both sides of the RS, considered as DI. Leaf water potential, total plant fresh weight and total dry weight of fruit were lower in DI than in FI and PRD. In PRD irrigation water use efficiency was improved by 83 % relative to FI. For DI dry mass partitioned into stems and leaves was higher, but dry mass partitioned into fruits was lower in PRD and DI than in FI. Fruit water content and fruit background skin colour were the same among treatments, but total soluble solids concentration was higher in PRD and DI fruits. Leaf calcium concentration was lower and the incidence of blossom-end rot was higher in DI and PRD than in FI. The PRD is more advantageous than DI and may be recommended for areas where water is scarce.