In vitro propagation of <i>Stevia rebaudiana</i> B. from nodal segments

Abstract

Stevia rebaudiana B. is the only crop that produces a non-caloric natural sweetener known as stevioside, which is 300 times sweeter than sucrose. This study was conducted to establish an in vitro reproduction protocol from nodal segments and the cost per plant produced. Consistency of the media (solid or liquid), concentration of macro-elements Murashige and Skoog (MS) (50 or 100%), type of citocinin (kinetin or 6-bencilaminopurine) and the amount of each citocinin (0, 2, 4, or 6 μM/L) were evaluated during the establishment stage on a basal MS formulation. Larger shoots were obtained from the liquid MS medium containing 50% inorganic salts supplemented with bencilaminpurine (BAP) (6 μM). For shoot multiplication, this same treatment was evaluated using three levels of kinetin (2, 4 or 6 μM) to stimulate growth and new shoots. During this stage, best shoot formation was observed when using 6 μM of kinetin in the medium. In vitro rooting evaluations were performed on a basal MS medium containing one of three auxins: Indole-Acetic Acid (IAA), Indole- Butiric Acid (IBA) or Naphthalene Acetic Acid (NAA), and one of five concentrations for each auxin. The highest number and best quality of roots were observed when using ANA (0.5 mg/L), 15 days after induction. During acclimation, the tallest plants and rate of survival were observed when using micro-tunnels as watering management systems, plastic bags as containers and Pro-Mix ‘BX’:sand (1:1) as substrate. Under laboratory conditions, and based on an average multiplication rate of 6, around 8,000 plants ready for acclimation can be produced from each established explant. The average cost is approximately $1.69 per acclimated plant.

Key words: Acclimation; micro propagation; micro-tunnels; natural sweetener; sweet herb; tissue culture.

DOI: http://dx.doi.org/10.5377/ceiba.v47i1-2.442

Ceiba, 2006. Volumen 47(1-2):11-18