Biology subjects

Brasier, C.

Publications and source records attributed to Brasier, C..

3 recordsLinked to original sources

bioRxiv2026

Mapping the distribution of elms in Britain after a century of Dutch elm disease

The establishment of novel pests and pathogens that devastate populations of trees is increasing around the world, giving rise to policy and management decisions about how to restore treescapes. Such decisions may be informed by the example of Dutch elm disease (DED) which caused most mature elms in Europe and North America to be lost in the mid-20th Century. Although affected elms can regenerate, they succumb again after several years. Considerable effort has been made to restore elm through: (1) cloning and breeding of surviving local trees, (2) introduction of resistant Asiatic species, (3) introduction or production of hybrids bred from local and Asiatic species. As trees are planted out into the landscape, it is necessary to record them, and monitor their survival. Here, we compile and map 82,244 elm trees in Britain recorded as 269 distinct elm species, hybrids and cultivars. The vast majority of records are for surviving field elm, English elm and wych elm, which would grow again to maturity if the virulence of the pathogen could be attenuated. The most commonly planted elms were the hybrids: Nanguen (commercial name Lutece), followed by New Horizon, Ademuz, Lobel and Sapporo Autumn Gold, each of which had over 200 occurrences. The current elm-scape of Britain represents much restoration effort and contains considerable genetic diversity.

plant biology↗

bioRxiv2026

Genomic diversity of elm trees for future treescapes

O_LIDutch elm disease has devastated the treescapes of Europe and North America, causing large elm trees to become largely absent. Several decades of work are now coming to fruition with the availability of potentially resistant cultivars for restoration. C_LIO_LIWe analysed genome-wide single-nucleotide polymorphisms derived from whole-genome sequences of more than 200 trees, including elm species, British morphological forms, disease-tolerant Spanish selections and cultivars from several breeding programmes. C_LIO_LIWhile confirming many specimen labels and multigenerational crossing records, our results also revealed unexpected misidentifications and origins of some samples. This included past hybridisation in some resistant selections thought to be pure species. We find that within our samples, field elm (Ulmus minor) is more genetically diverse than wych elm (U. glabra). We show that over ten British elm forms sometimes assigned species epithets fall within the genetic range of U. minor, U. glabra or hybrids. C_LIO_LIWith their exotic parentage, many of the elm cultivars introduced into Britain post-epidemic represent a considerable increase in nucleotide diversity over the still numerically large, native U. minor and U. glabra populations. Currently, the cultivars are being planted mainly as ornamentals. Their long-term arboricultural, adaptive and landscape suitability remains to be demonstrated. C_LI

plant biology↗

bioRxiv2026

Genetic mapping of Dutch elm disease resistance

Dutch elm disease (DED) has killed millions of field elms (Ulmus minor) in Britain and Europe since the 1970s, causing incalculable damage to landscapes and their associated biodiversity. While the species U. minor is highly susceptible to DED, some east Asian and Himalayan species of elm are resistant. These Asiatic species differ in their growth and form to U. minor and cannot fully substitute for it in the landscape. Several breeding programmes have attempted to generate trees that combine DED-resistance with the growth and form of U. minor via hybridisation and back-crossing. These have been partly successful, but further breeding is needed to fully realise these ambitions. Most recently in Britain, a complex resistant hybrid Wingham (FL493) was crossed with a surviving U. minor tree in Tonge Mill, Kent. Sixty progeny from this cross were tested for field resistance to DED and show segregation for this trait. Here, we analyse the genome of these progeny in order to: (1) construct a linkage map of the elm genome, and (2) identify regions of their genome derived from east Asian and Himalayan species that could be associated with DED-resistance. Such knowledge could accelerate future breeding programmes and enhance our understanding of the mechanistic basis of resistance.

genomics↗