In the Philippines, Stevia rebaudiana commonly known as "Sweet Leaf" is now recognized as a potential alternative sugar for tea products such as ginger and turmeric tea by several processors to cater to a significant number of people who are health conscious Because of the growing number of people who would like to endeavor on Stevia production most especially for integration in various established fruit farm areas in the country, there should always be available planting materials to support the increasing requirement. Micropropagation or in-vitro culture can potentially produce large quantity of Stevia plantlets in a short time.

A micropropagation protocol on half strength Murashige and Skoog (MS) media using two-stage culture procedures has been adopted in this research. Varying concentrations of cytokinins namely, Benzylaminopurine, (BAP), and Thidiazuron kinetin (TDZ), and auxin (Indole-acetic acid, IAA) were supplemented in the nutrient media to observe their effects on shoot development particularly on shoot induction, elongation and multiplication.

All the applied growth regulators promoted shoot induction and formation however, best response was observed in the combination of BAP and IAA at 0.5 mg/l each with five (5) induced shoots per explant which was not significantly different at lesserconcentration of BAP at 0.2 mg/l combined with 0.5 mg/l IAA that produced an average of 3.35 induced shoots after three weeks of culture. At these rates of hormone supplementation, the total number of shoots that may be produced could range from 2,500 to 3,125 after one cycle or from one explant alone after three months from induction to multiplication.

The shoots from selected induction medium were sub-cultured on the multiplication media. The medium containing 0.01 mg/1 TDZ produced greatest number of shoots but not significantly different with BAP alone at 0.5 mg/l as well as combination of BAP and IAA at 0.5 mg/l. The same trend was observed on shoot elongation particularly on shoot length and leaf number.

The micropropagation protocol using two-stage culture procedure may be adopted for Stevia. For best results, the induction medium should be supplemented with 0.2 mg/1 BAP combined with 0.5 mg/l IAA or BAP IAA, both at 0.5 mg/l. The multiplication medium on the other hand, should be supplemented by BAP alone at 0.5 mg/1.

Thesis (Master of Science in Crop Science - Horticulture)

Includes appendices and bibliographical references.