Chromosome numbers in some Artemisia (Asteraceae, Anthemideae) species and genome size variation in its subgenus Dracunculus: Karyological, systematic and phylogenetic implications

Abstract

Chromosome counts in 12 Artemisia species from Russia are presented in this paper. Chromosome numbers of A. czekanowskiana, A. globosa, A. ledebouriana, A. lithophila, A. macilenta, A. pycnorhiza and A. sosnovskyi are reported for the first time. The chromosome counts carried out in A. czekanowskiana (2n=10x=90) and A. macrantha (2n=12x=108) indicate cases of aneusomaty. The presence of a dicentric chromosome and acentric fragments or a B-chromosome is reported for one species. Besides these, genome size in 21 populations of 18 species of Artemisia belonging to the subgenus Dracunculus, mainly from Russia and Mongolia, has been assessed by flow cytometry. The nuclear DNA content ranges from 2C=4.21 to 2C=24.58 pg, and the nuclear DNA content per basic chromosome set (1Cx) from 2.06 to 3.00 pg. The constancy of genome size has been evaluated concluding that there exists a nuclear DNA loss (at the 1Cx-value level) within ascending ploidy levels. Possible correlations between genome size, morphological traits and the phylogenetic position of species have been tested.