从甜味成分种类及含量的不同，研究甜菊（Stevia rebaudiana Bertoni）实生群体和单株无性系的变化，从中选育优质甜味成分含量高的良种。主要结果：（１）在实生群体中，丰产株型（圆纺锤形株）占７.３％，其中，优质甜味成分Ｒ－Ａ含量超过Ｓｔ含量的Ｒ－Ａ型株占１０．９６％，它们的Ｒ－Ａ含量变幅为３．３～１２．０％。（２）Ｒ－Ａ型良种Ｊ－２单株无性系在繁殖达２０００万株时，叶片大小和含甙量均存在极显著差异，Ｒ－Ａ含量变幅为４．５～１２．２％。（３）从Ｒ－Ａ含量为３．８６％的实生群体中选出Ｒ－Ａ含量为７．０４～１２．０３％的单株及从Ｒ－Ａ含量为９．１０％的良种单株无性系中选出Ｒ－Ａ含量为１０．１５～１２．１５％的单株，它们的Ｒ－Ａ含量均大幅度提高。

The present paper deals with the investigation on the seedling population and clone variation from the difference of sweet component and content in Stma ~reEaudian0 Bertoni, improved types of high content of Rebaudioside A(R-A) was selected. The results showed : (1) There are 7. 3% high yielding plants in seedling population, in which the proportion of R-A type with content of R-A over St content is 10. 96%, and their R-A content varies from 3. 3 to 12. 0 %. (2) Among the selected improved clone 5-2, there are high significant difference in leaf size and steviosides content. The R-A content varies from 4. 5 to 12. 2 %. (3) The individuals with R-A content of 7. 04- 12. 03 % from seedling population (original content 3. 86 % ) and individuals with R-A content of 1 0. 15- 12. 15 % from improved individual clone (original content 9. I 0% ) were selected out.