1 Introduction
Roegneria C, Koch was erected and circumscribed by Koch (1848)
according to Roegneria caucasica C. Koch as the type species.
Nevski (1934) played a major role in popularizing the genusRoegneria , which he recognized distinct from AgropyronGaertner as an independent genus and described 49 species ofRoegneria . Tzvelev (1976) and Chen et al., (2006) includedRoegneria 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
circumscription of Elymus and Roegneria , andRoegneria 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. Based on these
morphological disagreements as a guide to resolve taxonomic treatment,
Baum et al. (1991) recognized only one genus. Cytogenetics and molecular
phylogeny provided additional support for the Roegneria as an
independent genus (Lu et al., 1988; Yen et al., 2011; Fan et al., 2013),
corresponding to genome system of classification in Triticeae. Since
then, Roegneria is a large genus in the wheat tribe, Triticeae
(Poaceae), which includes approximately 120 species that are of Asian
origin and distributed in the Qinghai–Tibetan Plateau, Central Asia,
East Asia, West Asia and South-east Europe (Baum et al., 1995; 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 ofRoegneria are allotetraploids with StY genomes (Yen &
Yang, 2011). The St genome is derived fromPseudoroegneria (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). Dewey (1984)
considered that the Y genome has its origin in Central Asia or
the Himalaya region, and may be extinct. Extensive cytogenetic and
molecular studies have suggested that the St(Pseudoroegneria ), W [Australopyrum (Tzvelev)
Á. Löve], V [Dasypyrum villosum (L.) Candargy],
and Xp [Peridictyon O. Seberg, S. Frederiksen & C.
Baden] genomes are potential donors of the Y genome (Liu et
al., 2006; Sun & Komatsuda, 2010; Fan et al., 2013; Lei et al., 2022;
Liu et al., 2022).
Here, we described a new species of Roegneria that was discovered
from the Hengduan Mountain Region during an expedition to the
Qinghai-Tibetan plateau in 2021 to collect germplasm of various members
of the Triticeae. The new species was discovered in stony slope of Haba
Snow Mountain with about 3200m and 2500m altitude. A few weeks later, it
was collected in stony slope of Yulong Snow Mountain with approximately
3200m altitude. The two localities are more than 90 km apart. This study
conducted on morphological observations, sampling of multiple
accessions, genomic in situ hybridization (GISH), and phylogenetic
reconstruction methods. Our goal was to determine whether this was the
case as a new species within Roegneria and, if so, to determine
the genomic constitution of the new species and provide it with an
appropriate name.