DEVELOPMENT OF ROOT INTERCEPT BAG-NFT SYSTEM FOR PRODUCTION OF HIGH QUALITY TOMATOES

An improved nutrient film technique system (root intercept bag-NFT system) for tomato (Lycoperisicon esculentum cv. ‘House momotaro’) was developed both for elevating soluble solid content of fruits without decreasing the yield and for alternating different nutrient solution diurnally. The root intercept bag-NFT (RIB-NFT) system was composed of 2 drip hoses for supplying nutrient solution and water for temperature control, and 2 gullies for draining the water. Each was composed of a polyester sheet pad used to control rhizosphere temperature via cool and warm water. A polyester sheet bag (30 cm × 20 cm, L × W) for rooting zone restriction of the tomato plant was used in the system. When tomato plants were grown by alternation of the nutrient solution diurnally in the regime of 1-6 dS m^-1, it was found that as the solution concentration increased, tomato yield reduced. Yield was greatly reduced with higher concentrations in the daytime compared to the nighttime and the decrease of yield was alleviated by lower concentration (4/1 dS m^-1) compared to 4/4 dS m^-1 in the nighttime. Sugar content was increased by higher concentration in the daytime. It was thought that the RIB-NFT system was suitable for alternating the concentration of nutrient solution to increase the sugar content of the tomato fruit without reduction of yield.