Use of of gibberellic acid (GA) as fruit enhancer for Queen pineapple

Queen pineapple (Ananas comosus L.) is one of the priority crops under the High Value Commercial Crop (HVCC) Program of DA in the Bicol Region [Philippines]. With the growing demand, their is a need to produce more quality pineapple fruits to expand local and foreign markets. To address this concern, Obrero (DA-5) verified the effect and profitability of GA application on fruit size improvement in Queen pineapple. The study was conducted from January 2004 to March 2006. GA is widely used plant growth regulator to promote fruit development in melons, pineapples, oranges and grapes; stimulates the growth of leafy vegetables such as spinach; break dormancy of seeds like potato; and promote seed development. To enhance fruit size, GA is applied at dry petal stage or when the developing fruits of pineapple have totally completed pollination where the flowers have dried or fall off. Findings of the study revealed the following: GA applied as fruit enhancer for Queen pineapple was found effective in terms of weight, length, and diameter. It also lengthened shelf life of fruits under ordinary storage condition but there was no positive effect on sugar content, fruit crown, and production of suckers. The dry season harvest in 3-15% increase in fruit weight corresponding to the GA rate while the rainy season harvest also registered 15-28% increase in fruit weight corresponding with the GA rate. However, effect was minimal as GA rate was reduced. Plants treated with GA yielded longer fruits compared with the control plants. Dry season harvest posted 0.41-0.58 cm increase while the rainy season crop had 0.63-1.48 cm increase in fruit length. Improvement in fruit diameter was more prominent at the top portion of the fruit with 0.28-0.61 cm increase for the dry season harvest and 0.38-0.98 cm for the wet season harvest. Increase in fruit diameter was also noted at the middle and bottom portion of the fruit. GA application delayed ripening of fruits. Plants created with GA had fewer fruits at maturity index of 1 or above at the time of harvest. The total number of fruits with GA application had 33-89% marketable life after 8 days of storage. Higher economic return was attained using the rate of three-fourths tablet per sprayer load (16 L water) which netted Php 12,564/ha during the rainy season harvest for the local market and Php 25,304/ha if the produce will be sold to the export market. For best results, the researcher recommended GA (Berelex tablet) application at dry petal stage using three-fourth tablet per sprayer load. However, for farmers with limited capital, one-half tablet per sprayer load can already bring substantial return. The researcher further recommends the inclusion of the technology in the production guide for Queen pineapple.