Abstract
The experiment was carried out in the lath house at the Station Research of Horticulture and Landscape Department/College of Agriculture/University of Diyala, Iraq for the fall season 2016-2017. The experiment included two factors, first one foliar application with polyamines (PAs), putrescine and spermidine, at concentrations of 0 (distilled water as control), 50 and 100 mg.l−1 of putrescine, and 50, 100 mg.l−1 of spermidine. The second factor was foliar spray with salicylic acid (SA) at concentrations of 0, 100 and 200 mg.l−1. Foliar application of PAs (putrescine and spermidine) led to enhance all vegetative growth and flowering qualities of gerbera (Gerbera jamesonii) cv. ‘Great Smoky Mountains’. Treatment with 100 mg.l−1 of spermidine gave the best results in terms of number of leaves, leaves area, relative chlorophyll content of leaves, flowering date, length and diameter of flower stalk, percentage of dry material in flowers. While, treatment with 100 mg.l−1 of putrescine gave the best results in terms of percentage of leaves dry material, number of flowers, and flower diameter. Foliar spray with SA affected positively in most vegetative and flowering qualities of gerbera, the best results were achieved when sprayed with 200 mg.l−1 in terms of percentage of leaves dry material, number of flowers, flower diameter, flower stalk length, percentage of flowers dry material. While, spraying with 100 mg.l−1 gave the best results in terms of number of leaves, leaves area, relative chlorophyll content of leaves, flowering date and diameter of flower stalk. Interaction between PAs (putrescine and spermidine) and SA showed significant improvement in all vegetative and flowering characters of gerbera. Treatment of 100 mg.l−1 of spermidine combined with 100 mg.l−1 of salicylic acid gave the best results in terms of number of leaves, leaf area, relative chlorophyll content in leaves, flowering date, flower diameter, length and diameter of flower stalk, percentage of flowers dry material. Treatment of 100 mg.l−1 of putrescine combined with 200 mg.l−1 of salicylic acid was surpassed in giving best total content of carbohydrate in leaves and number of flowers.
