Studies on the Development of Stevia (Stevia rebaudiana Bertoni M.) as a New Sweetness

The consumption of sugar in our diet increased so great that much U. S. dollars are spended to import sugar source from foreign contries. To replace a part of it we adopted mother plant and seeds of the well-known Stevia (Stevia rebaudiana Bertoni M.) originated from south America, from the Agricultural Experimental Station of Hokkaido, Japan, in 1974. In order to determine the growth condition of Stevia in our climate and soil condition, the results of survey and determination were as follows: 1. Germination rate of Stevia was averaged 33.6% at 35 th day after seedling and the maximum germination period was between 5 and 20 days after seedling. 2. The seedling rate of Stevia was about 8%. 3. Establishment of roots of Stevia propagated by cutting method was above 90% but only S-1 strain showed lower rate., 75%. 4. S-2 strain showed the best growth rate that was about 160cm by plant height and it was decreased by the following order : S-4, S-3, S-1, S-6 and S-5 strains. 5. S-4 strain resulted in 45 branches that was the highest number among strains tested and S-2 strain was the next. 6. The content of sweetening compound of Stevia, stevioside, was 5.3% in S-1, S-2, S-5 and S-4 strains but S-3 and -6 strains were relatively low content, 4.9%. From the above results we obtained Stevia could be propagated by cutting method and the growth conditions including plant height, number of branches and content of stevioside were relatively better in S-2 and S-4 strains that were differentiated by the shape of leaf.