Effects of summer day-time temperature on sugar content in several portions of watermelon fruit (Citrullus lanatus)

摘要

Effects of temperature on the sugar content of watermelons were investigated in the outer, middle and central portions of the fruit, respectively. Cubic boxes covered with transparent plastic film (designated as the film covering) and well ventilated wooden slats (designated as the shading), were put on watermelon fruits from 0500 to 1800 hours for 10 d from day 30 after anthesis (daa). Flesh temperature at all portions was highest in the film covering and the lowest in the shading. Rind thickness was least in the shading. Sucrose content was high in the middle portion of the fruit in the shading, but was low in the film covering. Glucose and fructose content was high in the central portion of the fruit in the shading but low in the film covering. Watermelon fruit with thin rind and high sugar content can be produced by lowering the day temperature by shading only the fruits.