Effects of Culture Method and Hydroponic Solution Nutrient Level on Bitterness and Quality of Cucumbers (Cucumis sativus L. cv. Kema)

establish an efficient cultivation for producing high qualitycucumbers (Cllcumissativus cv. Kema) ， a comparison of cucumbers grown in soil culture and hydroponic solution cu 1t ure with different nutrient levels was carried ou t. The hydroponically grown cucumbers were bitter compared with the cucumbers grown in soi l. The maximum and minimum fruit productions were obtained at high and low nutrient levels ， respectively. However ， most of the cucumbers were bitter when they were grown at high nutrient leve l. The cucumbers had the lowest concentration of nitrate ion in the hydroponic culture solution with low nutrient leve l. and vice versa. Nitrate ions may cause bitterness in cucumbers by promoting nitrogen metabolism ， which in turn favors the enzymatic synthesis of cucurbitacin C. From these results ， we conclude that the yield of bitter cucumbers can be reduced by growing them in soil culture rather than in rockwool cultur ・ eand in hydroponic solution with low nutrient leve l.