Abstract: Roegneria C. Koch is a relatively large polyploid perennial genus with 130 species in the Triticeae, and consisting of the St and Y genomes. There are different opinions about whether Roegneria is an independent genus, or whether it should be included in the genus Elymus L. For many species of Roegneria, their genome constitution and phylogenetic relationship are still unknown. More research about the maternal genome donor of the Roegneria species is needed. To investigate the phylogenetic relationships and maternal genome donor of Roegneria and its affinitive genera, phylogenetic analyses of two chloroplast regions ndhF and trnH–psbA sequences were carried out in this study. The results showed that: (i) Campeiostachys Drobow (StYH) and all Roegneria (StY, StStY) species were scattered with Pseudoroegneria Á. Löve (St) species; (ii) R. sinica Keng, R. schugnanica (Nevski) Nevski, R. seriotina Keng, and Elymus calcicolus (Keng) Á. Löve containing the St genome; (iii) there was differentiation among species of Pseudoroegneria; and (iv) the St genome in diploid, tetraploid, and hexaploid species are divergent. Thus, it is suggested that: (i) Pseudoroegneria served as the maternal genome donor of Roegneria, including four species with unknown genomic constitutions (R. sinica, R. schugnanica, R. seriotina, and E. calcicolus); (ii) species of Roegneria or Pseudoroegneria might serve as the maternal genome donor of Campeiostachys; and (iii) the St genome has undergone differentiation during polyploidization in diploid, tetraploid, and hexaploid species.

Key words: Campeiostachys, Elymus, maternal donor, ndhF, Roegneria, trnH–psbA