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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #334389

Research Project: Taxonomy of Landscape Trees and Shrubs

Location: Floral and Nursery Plants Research

Title: Genome size variation in elms (Ulmus spp.) and related genera

Author
item Whittemore, Alan
item Xia, Zheng-lian

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2017
Publication Date: 5/15/2017
Citation: Whittemore, A.T., Xia, Z. 2017. Genome size variation in elms (Ulmus spp.) and related genera. HortScience. 52(4):547-553.

Interpretive Summary: The elms (the genus Ulmus) are one of the most important tree crops for the $4.7-billion per year U.S. nursery industry. Utilization of these plants has been limited in recent decades by diseases introduced from outside the U.S., especially Dutch elm disease. Past research and breeding have been based on a small number of species. Additional elm species from Asia have been introduced to the West in recent years. In order to improve our understanding of genetic relationships among available elm species, a broad survey of genome size in species of elm and related genera was carried out using flow cytometry, a technique that measures the amount of genetic material (DNA) in a cell's nucleus. The results of our survey have improved our understanding of genetic diversity among the elms, confirmed that it is rare for elm species to have extra sets of chromosomes (polyploidy), and supported the currently recognized subgenera of elms. This work has allowed us to identify elms that have not been used in research and breeding that show promise for research on, and breeding for, resistance to Dutch elm disease. These results will be used by taxonomists, geneticists, and tree breeders working on elms and related genera.

Technical Abstract: The elms (the genus Ulmus) are one of the most important tree crops for the $4.7-billion per year U.S. nursery industry. Utilization of these plants has been limited in recent decades by diseases introduced from the Old World, especially Dutch elm disease. Past research and breeding have been based on a small number of species. Much additional germplasm has become available in recent years. In order to clarify genetic relationships among available elm species, a broad survey of genome size in species of elm and related genera was carried out using flow cytometry. The results of this survey have improved our understanding of genetic diversity among the elms, confirmed the rarity of polyploidy in this group, and supported the currently recognized subgenera of elms. This work has allowed us to identify hitherto unutilized germplasm that shows promise for research on, and breeding for, resistance to Dutch elm disease. These results will be used by taxonomists, geneticists, and tree breeders working on elms and related genera.