Colchicine induced mutation and enhancement of the steviol glycoside content in Stevia rebaudiana / Nur Izzati Azizan

Stevia rebaudiana is a sweet herb that belongs to the family Asteraeae. Steviol glycoside, a natural sweetener derived from Stevia leaves are 100-300 times sweeter than sucrose and contain a complex mixture of sweet diterpene glycoside. the mutagenic effect of colchicine to improve leaf and steviol glycosides yield in stevia was investigated. Stevia plant were treated with five different colchicine concentrations (0.5%, 1.00%, 1.50%, 2.0%, 2.5% and 0.0% act as control) for 48h. The plants were arranged in a completely randomized block design. Treated plants were characterized based on morphological traits such as plant height, leaf length and leaf thickness. The results obtained revealed significant difference (p≤0.05) in the morphological traits of the mutants when compared with the control. Overall, 2.00% colchicine concentrations resulted in higher average plant height by 36.0% ±0.6 leaf length increments by 43.0%± 0.7 and the leaf thickness increment by 5.0%±0.1. The improvement of the mutants' traits is concentration dependent and increases with increment in colchicine concentration. Therefore it is suggested that 2.0% concentration should be applied in improving stevia growth and yield related traits.