Location: Floral and Nursery Plants ResearchTitle: Phylogeny, biogeography, and classification of the elms (Ulmus)
|FULLER, RYAN - University Of Chicago|
|BROWN, BETHANY - Ball Horticultural Company|
|HAHN, MARLENE - Morton Arboretum|
|GOG, LINUS - Parkland College|
|WEBER, JAIME - Morton Arboretum|
|HIPP, ANDREW - Morton Arboretum|
Submitted to: Systematic Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2021
Publication Date: N/A
Interpretive Summary: The genus Ulmus (the elms) has been very important in American horticulture, but exotic diseases (Dutch elm disease and elm yellows) have seriously limited its use in recent decades. Continued effective utilization of elms in landscapes will require identification of sources of disease resistance. A better understanding of relationships between the elm species is needed to enable efficient identification, breeding, and selection of resistant taxa. A team of scientists from ARS, universities, and arboreta used DNA sequencing to elucidate relationships among elm species worldwide. These results will allow potential sources of resistance to DED and elm yellows to be evaluated, and the most compatible germplasm selected for testing.
Technical Abstract: A RAD-seq phylogeny is presented for the genus Ulmus, and a revised infrageneric classification is given. The previously accepted classification was based on a cpDNA phylogeny, but several well-marked clades in the chloroplast phylogeny are not recovered in the RAD-seq phylogeny and do not seem to represent valid clades in the organismal phylogeny. Our results support a broad species concept in Ulmus sect. Foliaceae. Three sections of the genus are disjunct between Eurasia and North America, indicating multiple dispersals between the northern continents. Some characters previously considered characteristic of subg. Oreoptelea are shared with the unrelated U. villosa and should be considered plesiomorphic in the genus.