Genetic Improvement of Stevia: A Natural Non-Calorie Sweetener

Abstract

Stevia rebaudiana, a native of South America, is a perennial herb of the Asteraceae family, also known as a natural sweetener due to the presence of steviol glycosides (SGs) in the leaves. China is the largest producer and exporter of stevia, while Japan is the primary consumer. The increasing demand for natural low-calorie sweeteners in the medicine and food industry has increased the pressure over stevia cultivation. Still, its cultivation and region-specific agrotechnologies need to be developed. The major bottleneck in stevia production are the lack of region specific cultivation technologies, non-availability of quality planting material, and uncharacterized and not properly conserved plant genetic resources. All these constraints have limited the stevia production to some specific regions of the world. Development of high-yielding cultivars with enhanced SGs content using modern breeding techniques is of prime importance to meet its increasing demand. Among the glycosides present in the leaves, rebaudioside-A is the most desirable glycosides having 250–300 times sweeter than sucrose, while, after bitter taste is due to the presence of stevioside and dulcoside. Therefore, the development of varieties with high rebaudioside-A and low stevioside content is highly desirable. This chapter focused on the improvement of propagation methods, characterization and conservation of genetic resource in stevia and its utilization in crop improvement programs.