EFFECT OF SOME GROWTH REGULATORS ON THE GROWTH AND FLOWERING OF TULIP PLANTS CV (JUDITH LEYSTER)

The research was conducted in the open field of Al-Noor Al-Ahly nursery to study the effect of different growth regulators on the growth, flowering and bulb formation of Tulipa gesneriana L. bulbs grown in pots. The studied factors included the following: The vegetative were sprayed with salicylic acid two months after planting at a concentration of 0 and 100 mg.L-1 in addition to the treatment of bulbs with the growth regulator paclobutrazol by pre-soaking the bulbs at concentrations of 0, 25 and 50 mg.L-1 and the control treatment was soaked with distilled water. After the bulbs are planted and grown, the shoots are sprayed to until wet with Gibberellic acid after a month and a half of planting, at concentrations 0, 50 and 100 mg.L-1. The results indicated that spraying with salicylic acid did not have a significant effect on the characteristics of the vegetative growth, but it significantly increased the number of bulbs and bulblets formed to 9,650 bulbs. plant-1, vs 8,445 bulbs.plant-1 in control treatment. The pre-soaking of bulbs with paclobutrazole at a concentration of 25 mg.L-1 led to a significant decrease in plant height compared to other treatments, except for the treatment with paclobutrazole at a concentration of 50 mg.L-1. It also led to delaying the flowering date to 119.3 days and increasing the fresh weight and specific weight of bulbs and bulblets, which amounted to 42,705 g and 41.583 g, respectively. It differed significantly from all studied treatments, and the intensity of chlorophyll increased, amounting to 62.579 SPAD and the number of bulbs and bulblets formed on the plant 10,708 bulbs.Plant-1 when soaking with a high concentration of paclobutrazol. Spraying with gibberellic acid at a concentration of 50 mg.L-1 led to an increase in the height of the plant and reached 31.25 cm, in addition to an increase in the diameter and weight of the daughter bulb, which amounted to 32,683 mm and 15.547 g, respectively.