Morphological Identification of Elymus sibiricus,E. nutans,and E. burchan-buddae,and Their Genomic Relationships

In order to investigate morphological variations of Elymus sibiricus L., E. nutansGriseb., and E. burchan-buddae (Nevski) Tzvelev ［=Roegneria nutans (Keng) Keng］,and to explore their systematic relationships, six morphological characters were measuredand compared between the Elymus species. Interspecific hybridizations between E. nutansand E. sibiricus, and E. burchan-buddae were carried out with the aid of embryo rescue.Chromosome pairing behaviour was also analysed at metaphase- I of meiosis in pollen mother cells of F₁ hybrids. Morphologic characters, such as length of spikes and length of glumesvaried considerably between different individuals of each species, whereas length and widthof paleas were quite stable and different between species. The interspecific hybrids were completely sterile and their meioses were irregular. Meiotic configuration of E. nutans × E. burchan-buddae was 7.70I +13.40Ⅱ+0.06Ⅲ+0.08 IV, whereas that of E. sibircus×E.nutans was 11.98I+9.61Ⅱ+0.64Ⅲ+0.39Ⅳ+0.01V. It is concluded from the morphological and cytological study that (1) it is possible to identify the three Elymus speciesusing the palea character, in addition to other traditionally applied characters; (2) Elymusnutans and E. burchan-buddae have a comparatively high genomie relationship, while E. nutans and E. sibircus have a relatively low genomic affinity to one another; and (3) a certainchromosome pairing regulator was presented in the hybrid between E. burchan-buddae andE. nutans.