Pre-planting Exogenous Application of Gibberellic Acid Influences Sprouting, Vegetative Growth, Flowering, and Subsequent Bulb Characteristics of 'Ad-Rem' Tulip

Tulip (Tulipa gesneriana L.) is a fascinating bulbous cut flower, and also used for potting, bedding, and border purpose. However, under the sub-tropical climatic conditions, quality tulip flower production is severely affected by its non-uniform bulb sprouting, lack or erratic flowering, small flower stalk, and short vase life. Hence, this study was performed to evaluate the potential of gibberellic acid (GA(3)) on sprouting, vegetative growth, flowering, flower quality, and vase life, including different bulb characteristics of 'Ad-Rem' tulip. Tulip bulbs were dipped in aqueous solution of different GA3 concentrations (0, 50, 75, 100, 125, and 150 mg L-1) for 30 min with Tween-20 (0.01%) as a surfactant. Tulip bulbs treated with 100 mg.L-1 GA(3) sprouted in significantly less number of days, exhibited higher sprouting percentage, more plant height, leaf area, leaf chlorophyll, photosynthesis rate, flower stalk length, stalk diameter, and fresh and dry flower stalk weight. Moreover, 100 mg.L-1 GA(3) application also decreased overall flower emergence time, increased flower size, produced attractive, glowing, and sturdy flowers with increased quality, and extended the vase life of 'Ad-Rem' tulip flowers up to 2.9-folds. However, 150 mg.L-1 GA(3) application exhibited better results regarding daughter bulblets per clump with a subsequent increase in bulb diameter, and weight compared to other treatments. Additionally, significant correlation was also found among different growth, flower, and bulb characteristics of GA(3)-treated tulip plants. Hence, 100-150 mg.L-1 pre-planting exogenous application of GA(3) may be effective for quality tulip production under the sub-tropical climatic conditions.