Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Committee Chair(s)

Yajun Wu, Richard R.-C. Wang


Yajun Wu


Richard R.-C. Wang


David Hole


The Triticeae tribe DUMORTER in the grass family (Poaceae) includes the most important cereal crops such as wheat, barley, and rye. They are also economically important forage grasses. Elymus is the largest and most complex genus with approximately 150 species occurring worldwide. Asia is an important centre for the origin and diversity of perennial species in the Triticeae tribe, and more than half of the Elymus are known to occur in the Asia. Cytologically, Elymus species have a genomic formula of StH, StP, StY, StStY, StHY, StPY, and StWY. About 40% of Elymus species are still unknown for the genomic constitution and some have questionable genomic combination. However, the origin of the Y genome is unknown. In order to identify the origin of the Y genome, 212 accessions of Elymus, Pseudoroegneria, and Hordeum species were tested using a Y genome specific Sequence Tagged Site (STS) marker. We obtained evidence supporting the hypothesis that the Y genome in some Elymus species shared a progenitor genome with the St genome. Our study suggested that Pseudoroegneria spicata (PI 232134), P. ferganensis (T 219), and P. libanotica (PI401326) are the donors of the Y genome in the Elymus species. The DNA sequences of the Y-genome marker in these three Pseudoroegneria species are more similar to those obtained from Elymus species having the Y genome than those from Hordeum marinum and H. murinum, making the Xa and Xu genomes less likely the donors of Y genome.