Cytology of the Elymus (Agropyron) elongatus complex

Abstract

The taxa cytologically studied in the Elymus (Agropyron) elongatus complex included three subspecies of E. elongatus, i.e., ssp. elongatus and ssp. haifensis (2n= 14) and ssp. flaccidi-folius (2n = 28), as well as E. varnensis (2n = 70). A brief taxonomic treatment of these different types is presented. Differences in karyotype were observed between materials of ssp. elongatus that have different origin as well as between ssp. elongatus and ssp. haifensis. Both subspecies have heteromorphic chromosome pairs. In the case of ssp. flaccidifolius, it was possible to arrange the chromosomes in seven groups of four. These groups correspond to the seven pairs of the diploid subspecies which indicates the likelihood of an autopolyploid origin of the tetraploid subspecies. That the chromosomes in most of these groups could be further differentiated into pairs suggests that “intervarietal” crossings have also been involved. Meiosis was studied in ssp. elongatus and flaccidifolius. The satellited chromosomes detectable in E. varnensis were few; they represent, however, types that are found in the three subspecies of E. elongatus. This indicates that the two species are interrelated.