IMPACT OF PINCHING DATE AND FOLIAR SPRAY WITH ASCORBIC ACID ON GROWTH AND FLOWERING OF CHRYSANTHEMUM PLANT (Chrysanthemum morifolium Ramat) CV. 'DEBONAIR'

Abstract

ABSTRACTThe experiment was conducted in the lath house of the research station of Horticulture and Landscape Design Department/College of Agriculture/University of Diyala to study the effect of pinching date, which included three levels (without pinching, pinching after 15 and 30 days of transplanting) and foliar spray with ascorbic acid at four levels (100, 150 and 200 mg.l-1, as well as foliar spray with distilled water as a control treatment) in vegetative and flowering growth characteristics of chrysanthemum plant cv. 'Debonair' with flowers in violet color. The research was carried out as a factorial experiment (3×4) in split plots according to a Randomized Complete Blocks Design (RCBD) with three replicates. Treatments of pinching date represented the main plots and treatments of foliar spray with ascorbic acid were the secondary plots. The results can be summarized as follows: Pinching date was significantly affected on both vegetative and flowering growth characteristics of chrysanthemum plant. It was found that the highest rate of plant height was achieved in control treatment (without pinching) and significantly superior to the pinching treatments after 15 and 30 days of transplanting which did not differ significantly. Pinching treatment after 15 days of transplanting led to a significant increase in number of branches.plant-1, number of leaves.plant-1, leaves area.plant-1, percentage of total carbohydrates in leaves. Late pinching treatment (30 days after transplanting) significantly increased age of flower on the plant, while control treatment (without pinching) led to early emergence of first flower and a significant increase in flower diameter. Foliar spray with ascorbic acid led to improving all vegetative and flowering characteristics except flower diameter of chrysanthemum plant. Foliar spray at concentration of 150 mg.l-1 was significantly superior in giving the best results for plant height, number of branches.plant-1, leaves area.plant-1, relative chlorophyll content in leaves, vegetative dry weight, percentage of total carbohydrates in leaves, number of flowers.plants-1, age of flower on plant, dry weight of flower and total petals content of anthocyanin. Interaction between pinching date and foliar spray with ascorbic acid had a significant effect on all vegetative and flowering growth characteristics. Treatment of P30×AsA150 was superior and gave the best results for number of leaves.plant-1, leaves area.plant-1 and flower age on the plant. Treatment of P15×AsA150 was significantly superior in number of branches.plant-1, vegetative dry weight and number of flowers.plants-1, while treatment of P0×AsA150 was superior in content of relative chlorophyll in leaves, percentage of total carbohydrates in leaves, flower dry weight and total petals content of anthocyanin.