Effect of Spraying with Amino Acids (Tryptophan and Glycine) and Nano-Potassium on some Vegetative Growth Characteristics of Stevia Plant (Stevia rebaudiana Bertoni)

Abstract

Researchers from the College of Agriculture at the University of Kerbala in the Karbala province of Iraq used a greenhouse to examine the effects of nano-potassium and the amino acids tryptophan and glycine on the development of the stevia plant and the concentration of its active substances in the local climate. The experiment had three replicates and was carried out using a factorial trial design within a randomized complete block design (R.C.B.D). The study had three variables. The first component was tryptophan, with three concentrations (0, 25, and 50 mg. L-1), the second factor was glycine, with three concentrations (0, 500, and 1000 mg. L-1), and the third factor was nano-potassium, with two values (0, and 100 nmol L-1) (0, 2 g. L-1). The findings demonstrated that the variables under study, whether acting separately or in combination, significantly improved all characteristics of vegetative development. The triple interaction treatment (50 mg. L-1 tryptophan + 1000 mg. L-1 glycine + 2 g. L-1 potassium) gave the highest percentages for plant height, number of main branches, leaf dry weight, number of total leaves, and total chlorophyll content, where recorded (89.68 cm, 12.67 main branches. plant-1, 48.43 g. plant-1, 189.09 leaves. plant-1, 12,609 mg. 100 g-1 fresh weight, respectively). It may be concluded that the application of an integrated fertilization program can sustain or enhance stevia production in both quantity and quality under challenging environmental circumstances.