Biosystematics of Genus Elymus

Roegneria yenchiana: A new species in the Triticeae (Poaceae) from the Hengduan Mountain region

“…GISH results confirmed that R. yenchiana is a tetraploid (2 n = 4 x = 28) with the StY genome constitution. Based on the genomic system of classification as a guide to resolve taxonomic treatment in Triticeae (Barkworth & von Bothmer, 2009 ; Baum et al., 1995 ; Dewey, 1984 ; Wang et al., 1994 ; Yen & Yang, 2011 ), this species should be included in the genus Roegneria . Phylogenetic analysis based on all three unlinked single‐copy sequences showed that the St ‐genome homoeologous types of R. yenchiana were grouped with the sequences of Pseudoroegneria and Roegneria , and the Y ‐genome homoeologous types of R. yenchiana were clustered with the sequences of Roegneria with high statistic supports (BS > 70% and PP > 0.9).…”

“…Chen and Zhu ( 2006 ) and Tvelev ( 1976 ) included Roegneria in Elymus because of their many commonly morphological characters, e.g., plants usually tufted; lemma lanceolate‐oblong, rounded abaxially, 5‐veined, veins connivent at apex. Despite the criteria used, there is morphological disagreement over the circumscription of Elymus and Roegneria , and Roegneria is distinguished from Elymus by single spikelet per rachis node with lanceolate glumes and short and broader palea as well as glume retention after caryopsis abscission (Baum et al., 1991 , 1995 ; Yen & Yang, 2011 ). Based on these morphological disagreements, Baum et al.…”

“…Cytogenetics and molecular phylogeny provided additional support for Roegneria as an independent genus (Fan et al., 2013 ; Lu et al., 1988 ; Yen & Yang, 2011 ), corresponding to the genome system of classification in Triticeae (Dewey, 1984 ). Since then, Roegneria is a large genus in the wheat tribe (Poaceae: Triticeae), which includes approximately 100 species that are of Asian origin and distributed in the Qinghai–Tibetan Plateau, Central Asia, East Asia, West Asia and South‐east Europe (Yen & Yang, 2011 ). The largest number is found mainly in the mountains of the Qinghai–Tibetan Plateau, with 33 species being recorded.…”

“…Most species of Roegneria can usually be recognized in the field by a combination of characters: (a) lack of underground rhizomes; (b) spikes often slightly curved to erect, with arrangement of spikelets nearly parallel to and appressed to rachis and only one per node, with long rachis internodes; (c) spikelets functionally disarticulating above the glumes (Baum et al., 1995 ). Cytologically, all the species of Roegneria are allotetraploids with StY genomes (Yen & Yang, 2011 ). The St genome is derived from Pseudoroegneria (Nevski) Á. Löve (Löve, 1984 ; Wang et al., 1994 ).…”

“…The St genome is derived from Pseudoroegneria (Nevski) Á. Löve (Löve, 1984 ; Wang et al., 1994 ). It is unknown where the Y genome originates, although it is a fundamental Roegneria genome (Yen & Yang, 2011 ). The tetraploid species Roegneria alashanica Keng was found to have the StSt Y genome constitution (Wang & Jensen, 2017 ), suggesting that the Y genome might derive from St through StY .…”