Effect of GA3 Treatment on Bud Formation, Fruit Set, and Enlargement in Ardisia pusilla

The objective of this study was carried out to investigate the proper plant growth regulator for increasing the number of flower, fruit set, and to enlarge the size of the berries in Ardisia pusilla. Flower bud formation was used rooted cutting, and fruit set, enlargement, and coloration of fruit were used with two years-old. GA(3) concentrations were treated with 0, 100, 200, or 400 mg.L-1. Flower bud formation was effective in 400 mg.L-1 GA(3) and it was 1.8 times greater than control. Plant growth regulators were applied by foliar spray at full bloom stage to increase the fruit set. As a result, GA(3) was the most effective for increasing fruit set. Also, auxins of 4-CPA (Tomatotone, Donbu hitech Co., Korea) and dichloprop triethanol amine (Antifall, Bayer Crop Science Co., Ltd., Korea) were effective. When GA(3) concentrations of 0.5 and 1.0 mg.L-1 were used, fruit set (%) reached to 70% and 77%, respectively. Effectiveness of GA(3) was 1.8 times greater than control. Also, auxins, dichloprop triethanol amine increased to about 7-12% during fruit setting, but cytokinin and anti-gibberellin were ineffective. To investigate the fruit enlargement and coloration, GA(3) was treated with 0.3, 0.6, and 1.2 mg.L-1. Fruit enlargement was achieved to about 15% by GA(3) 0.6 mg.L-1 when GA(3) was treated 3 times at the interval of 1 month per treatment when fruit size was about 2-3mm (after full-blooming two months). But anthocyanin contents for coloration of fruit skin were not significant according to GA(3) concentration. The results showed that GA(3) enhanced bud formation, fruit set and enlargement of fruit size in Ardisia pusilla.