Evaluating The Role of Meta-Topolin and Tryptophan Foliar Application in Reducing The Growth Period Before Budding in Flying Dragon [Poncirus Trifoliata (L.) Raf. Var. Monstrosa (T. Itô) Swingle] Rootstock

Foliar spraying using different levels of meta-topolin (0, 10, 20, and 30 mg L-1) and tryptophan (0, 50, and 100 mg L-1) was done to investigate their influence on the seedling growth and chemical composition of Flying Dragon rootstock. Additionally, a factorial experiment was conducted utilizing three replications following a randomized complete block design on the success of Washington navel orange scions. The study was conducted from September 2022 to June 2023 at a lath house at the Department of Horticulture and Landscape Gardening, College of Agriculture, University of Anbar, Iraq. The results revealed that the two study factors significantly impacted all traits, particularly at higher concentrations. The 30 mg L-1 meta-topolin treatment significantly increased plant height, leaves number, leaves area, stem diameter, number of buddable seedlings, vegetative dry weight, stem total carbohydrate, leaves nitrogen content, and total chlorophyll content, and scion success. Moreover, 50 mg L-1 tryptophan foliar spraying significantly increased all the above traits, while the control treatment had the lowest values