Morphological identification of genomic genera in the Triticeae

Abstract

, Northwest Frontier Province, PakistanOur goal was to determine whether the genomic groups of perennial species Triticeae having solitary spikelets could be identified morphologically and, if so, to construct identification keys that could be used for this purpose. If so, it would strengthen the argument for recognizing such groups as genera. We conducted Discriminant and Random Forest ® analyses of 61 characters scored on 218 herbarium specimens representing 13 genomic groups. In addition, we closely examined some additional characters that came to our attention, evaluating our findings on specimens not scored for the two kinds of analysis. Random Forest ® analysis was almost always more successful in distinguishing the genomic groups, whether separating all 13 groups or a subset of the 13. The results suggest that it is usually possible to identify the genomic group to which a specimen of perennial Triticeae with solitary spikelets belongs on the basis of its morphology but that doing so will require examination of characters that have not been considered particularly important in the past. Among these are the length of the middle inflorescence internodes, the width of the palea tip, and the morphology of the glumes. Generic descriptions and keys have been posted to the web (see http://herbarium.usu.edu/ triticeae). They include all the genera that we recognize in the tribe, not just those included in the analyses, and will be improved as additional information becomes available.

A worldwide phylogenetic classification of the Poaceae (Gramineae)

“…Triticinae is derived from within Hordeinae s.l, but no new infratribal classification has been offered (Seberg & Petersen, 2007). The tribe is well known for reticulate evolution and the classification of genera is largely based on genome types and pairings (Barkworth et al, ; Anamthawat‐Jonsson, ; Sha et al, ; Sun ; Wang & Lu, 2014; Zhang et al, ).…”

Biosystematics and evolutionary relationships of perennial Triticeae species revealed by genomic analyses

“…Yen & Yang () and Barkworth et al () defined genera delimitation based on genome constitutions of species. Two new genera, Douglasdeweya and Conconorochloa , were erected by Yen et al () and Barkworth et al () for the StP (Wang et al, ; Jensen et al, ) and StYHW genome combinations (Zhang et al, ) in known species, respectively.…”

Breeding Perennial Grain Crops Based on Wheat

“…There is continuing debate on the relative merits of a genomically based taxonomic system versus one that is focused on morphology (Dewey, 1984;Barkworth et al, 2009). Work to determine the relatedness of different species based on observation of meiosis in F 1 hybrids has been helpful for breeders, who are more interested in genetic compatibility than morphology (Wang, 1989;Wei and Wang, 1995).…”

“…Disagreement over genomic constitutions and their symbols in Thinopyrum (and other genera in the Triticeae) makes listing them here difficult and might contribute to the confusion. Conversation about how genomic and morphological data should be balanced for taxonomic placement and nomenclature continue to restructure the placement of species and boundaries of genera (Barkworth et al, 2009). We outline some general strategies and combinations for hybridization below, but a review of the literature relevant to species of interest is advised before developing a breeding program.…”