Karyological Analysis of Introduced <i>Stevia rebaudiana</i> Bertoni (Asteraceae) in Moderate Climate

Abstract

The karyological results of Stevia rebaudiana introduced in the Primorye region (Far-east of Russia) are presented. S. rebaudiana has a chromosome number of 2n=2x= 22 with a karyotype formula of 8m+2sm+1st. The chromosome size is very short (1.1-3.1 µm). The relative length of chromosomes varies from 5.1 to 16.16%. The centromere index (CI) varies from 15 to 49%. An interphase nucleus of S. rebaudiana has one or two nucleoli, which suggests the presence of one pair of nucleolar chromosomes. The clonal propagation method provides a high multiplication rate and also preserves these plants in vitro within a cold period. S. rebaudiana has adapted to the new ecological niche on a constant chromosomal number within the genotype reaction norm.