The University of Hohenheim，too，is researching into Stevia；this photo was taken at the horticultural experiment station. Photo：University of Hohenheim

Background

Providing access to genetic resources and ensuring their sustainable use is a key objective of the Convention on Biological Diversity（CBD）adopted in 1992 so，too，is sharing，in a fair and equitable way，the benefits arising from the utilisation of these resources. The aim is to create incentives for the sustainable and profitable utilisation of biological diversity to the benefit of developing countries. For these countries are home to some 80 percent of species diversity worldwide. Nonetheless，despite such governance mechanisms and intensive debate at international level，there are hardly any examples as yet of successful and sustainable implementation of equitable benefit sharing in relation to an animal breed or plant variety of global commercial interest. Utilising Stevia，the sweet herb of Paraguay，is of very great commercial interest. Benefit sharing as envisaged by the CBD has not yet emerged.

This article explores the setting and presents experience gathered in relation to benefit sharing. This experience may provide a basis for ways to handle other genetic resources of commercial importance.

“Ka’a he’ê”-“sweet herb”-is the name given by the indigenous Guaraní people in eastern Paraguay to the perennial shrub whose leaves they have used for centuries to sweeten their mate tea. They were also aware of the healing properties of the sweet herb and made use of these-although modem medicine continues to doubt the pharmacological effect of Stevia.

Until about one hundred years ago，Ka’a he’ê or Stevia rebaudiana Bertoni，as the plant is called in scientific nomenclature，only grew in the wild. The Swiss botanist Moises Bertoni，who “discovered” the plant towards the end of the 19th century，classed it in the sunflower family （Asteraceae）and gave it its scientific name，and thus made the plant known outside Paraguay. In 1908，Stevia was domesticated for the first time. Its commercial use only began in the late 1960s and early 1970s. The aqueous extract of the leaves was used to sweeten beverages，cakes，ice cream and other foodstuffs. Japan，China，Brazil，Switzerland and the United States were the first countries to use Stevia as a sweetener on a larger scale.

Stevioside is the principal component of Stevia. It makes the leaves of the plant 20 - 30 times sweeter than sugar. In chemical terms，this is a glycoside，i.e. sugar molecules bound to alcohol. The plant contains further，related constituents that also have a sweetening effect. Depending upon the specific plant material and the area in which it is cultivated，one kilogram of dried Stevia leaves contains 40 - 200 grams of sweettasting glycosides.