Comparative chromosomal features and new karyological data in Salvia: B-chromosomes, polyploidy, dysploidy and symmetric karyotypes

The genus Salvia is characterized by such small chromosomes, which has so far restricted the cytogenetic studies. Therefore, karyomorphological aspects of the chromosome complement were rarely analyzed in the genus. The aim of this study was to report the interspecific relationships and new chromosomal data in Salvia. The chromosomal records of 25 taxa were herein provided, 8 of which were reported for the first time, 3 presented new chromosome numbers, and 14 agreed previous reports. In addition, a detailed chromosomal data of 16 taxa were provided. Eleven different chromosome numbers (2n = 12, 14, 16, 18, 22, 26, 28, 36, 38, 42, and 52) were found by the basic number of 6, 7, 8, 9, 11, and 13. S. candelabrum was the only taxon with B-chromosomes. Salvia algeriensis had different chromosome numbers with probably dysploidy mechanisms. The polyploidy was demonstrated by the prevalence of cells with 2n = 4x = 28, 36, and 52 (tetraploid) and 2n = 6x = 42 (hexaploid). No clear relationship was observed between basic numbers/ploidy level and subgenera. Salvia taxa had different karyotypes in terms of asymmetry degrees, which had relatively low asymmetry in nine taxa, average asymmetry in five taxa, higher intrachromosomal asymmetry in S. glutinosa, and higher interchromosomal asymmetry in S. interrupta. S. taraxacifolia, S. canescens, S. jurisicii, and S. nutans were cytotaxonomically very close species by basic numbers of x = 11 and 13. The possible ancestral number is x = 11. The results contributed to some missing parts in Salvia cytotaxonomy.

Automated summary

This study reports on the interspecific relationships and chromosomal data in the genus Salvia. It found eleven different chromosome numbers with the basic numbers of 6, 7, 8, 9, 11, and 13. The degree of asymmetry varied among the Salvia taxa. The ancestral number is likely to be 11. These findings contribute to the cytogenetic studies of Salvia plants.