Research Activity

Title:Evaluation Of Light Bulbs And The Use Of Foliar Fertilizer During Off-Season Production Of Dragon Fruit

Dragon cactus is photoperiodic, meaning it flowers in response to the length of the day and night. It produced flowers and bears fruit during the long-day months of May to October thatrequiresshort dark night to produce flowers. Controlling the day length or photoperiod by providing supplemental lighting can influence flower induction.The induction of flowering by manipulating the environment is possible already in other countries. In Taiwan, the flowering of dragon fruit can be prolonged between September and March. The flowering can be induced by breaking the dark period with supplemental lighting between 10:00 p.m. and 2:00 a.m., allowing off-season production from November to April. The fruits produced during the cool season in Taiwan are more desired in the market than fruits from summer crops because the off-season fruits are larger and sweeter. The recommend lighting utilizes 100 watt-incandescent light bulbs at about 4–5 feet spacing suspended about 6 feet above the ground (Zee et al. 2004).

In the Philippines, the use of incandescent light bulbs might be prohibitive in the off-season dragon fruit production because this requires high electricity cost. The search of alternative bulbs is deemed necessary. Together with the incandescent bulb, other locally available bulbs such as CFL and LEDwere evaluated to compare their profitability as supplemental lighting during off-season dragon fruit production. In addition, the foliar fertilization can possibly increase the yield.Thus, this study was conducted.

The experiment was conducted at the dragon farm of MMSU. In each treatment, fifteen posts of dragon cactus were usedlaid out in three rows and five posts in each row. The inner row was used as sampling area.

The experiment was laid out in a Split Plot Design where light bulbs served as the main plot and foliar fertilization as the sub-plot. The main plotwas100 watt-incandescent bulb (IB), 26 watt-compact fluorescent bulb(CFL) and 6 watt- light emitting diode (LED). The sub-plot waswith or no foliar fertilizationwhere thefoliar fertilizerwas applied using the manufacturer’s recommendation at weekly interval.

Supplemental lighting was introduced between 10 o’clock in the evening until two o’clock the following morning by suspending the bulbs. These were positioned at the center of the four posts of dragon cactus about five feet above the ground.

Data on the light intensity of the different bulbs, weight of fruits, number of fruits, yield per post as well as the cost and return were gathered.