ASPECTOS DE LA BIOLOGÍA REPRODUCTIVA DE STEVIA REBAUDIANA (ASTERACEAE).

The genus Stevia Cav. (Asteraceae) consists of about 200 species in the Americas. Stevia rebaudiana (Bertoni) Bertoni, originally from Paraguay, is the only cultivated species. It has widely been studied chemically, because of the active compounds found in the leaves. However, there is controversy about its reproductive system, as some authors consider it an obligate apomict, while others a sexually reproducing species. In order to clarify this issue: the megasporogenesis, megagametogenesis, floral phenology, pollen viability, and stigmatic receptivity were studied in three ecotypes, under self-pollination and cross-pollination. According to our results, the plants reproduce sexually and have a self-incompatibility system that prevents self-fertilization. [ABSTRACT FROM AUTHOR]