GROWTH, YIELD, AND POSTHARVEST ATTRIBUTES OF GLASSHOUSE TOMATOES PRODUCED UNDER DEFICIT IRRIGATION

In glasshouse-grown tomatoes (Lycopersicon esculentum Mill. 'Virosa'), deficit irrigation (DI), in which plant water potential was allowed t o decrease from -0.5 to -1.2 MPa, reduced plant growth and fruit yield , size and count, and caused blossom-end rot. Deficit-irrigated fruit had higher color intensity, lower water content, and higher concentrat ion of sucrose, glucose, and fructose than web-watered (control) fruit . Fruit concentrations of Ca, Mg, and K were the same for both treatme nts on a dry weight basis, but they were higher in DI fruit than in co ntrol fruit on a fresh weight basis. Fruit gas exchange was measured f or two 30-day-apart harvests. For both harvests, DI fruit produced hig her quantities of CO2 and ethylene than control fruit. Ethylene and CO 2 production peaks coincided for the first harvest in both treatments. In the second harvest, the CO2 production peak preceded that of ethyl ene. Despite yield reduction, DI enhanced fruit desirability in terms of higher concentration of soluble sugars and higher color intensity.