Genome Analysis, Morphology, and Taxonomy of Elymus gmelinii and E. strictus (Poaceae: Triticeae)

Elymus gmelinii (Ledeb.) Tzvelev and E. strictus (Keng) A. Love were studied to describe their reproductive characteristics, cytogenetic behavior, genomic constitution, and morphological variations. Both species were tetraploids (2n = 28) and behaved as strict allotetraploids, averaging 13.99 and 13.95 bivalents per cell, respectively. Both species were self-fertile. Hybrids were obtained between E. gmelinii and E. strictus, and the following "analyzer" parents with known genomic formulas: Pseudoroegneria spicata (Pursh) A. Love, 2n = 14, SS; P. stipifolia (Czern. ex Nevski) A. Love, 2n = 14, SS; Elymus canadensis L., 2n = 28, SSHH; E. lanceolatus (Scribn. & Smith) Gould, 2n = 28, SSHH; E. dentatus (Hook. f.) Tzvelev ssp. ugamicus (Drob.) Tzvelev, 2n = 28, SSYY; E. abolinii (Drob.) Tzvelev, 2n = 28, SSYY. Chromosome pairing in this series of hybrids demonstrated that E. gmelinii and E. strictus contain the S and Y genomes. Morphological variation of 36 characters was measured for both taxa, utilizing 24 operational taxonomic units (OTUs) of E. gmelinii, and 38 OTUs of E. strictus. The data are analyzed using principle components and cluster analysis. Based on this study it is proposed that E. strictus be reduced to a subspecies of E. gmelinii.