EFFECTS OF NUTRIENT MANAGEMENT ON YELLOW SHOULDER FRUIT INCIDENCE AND CAROTENOID METABOLISM FOR TOMATO GROWN IN THE EXTREMELY LOW VOLUME SUBSTRATE

In the present study, each tomato (Solanum lycopersicum L. ‘CF Momotaro Yoku’) plant was cultured in 250 mL D alphabet shape pot which was filled with granular rockwool. At the same time, we combined low nod order pinching and high density planting. Low concentration nutrient solutions were distributed through frequent and small amount drip fertigation which was controlled by closed recirculating growing system and integrated solar radiance. Two experiments with 5 different nutrient concentration regimes in Experiment 1 and 2 levels of K concentra¬tion in Experiment 2 were carried out to investigate the effects of nutrients on yellow shoulder fruit incidence (YSI) and carotenoid metabolism. YSI decreased with in¬creasing of potassium application amount. There was strong negative linearity correlation coefficient between them (R²=0.93). Except β-carotene, fruit red color and the content of lycopene and phytoene in tomato fruit increased with K fertigation levels.