Abstract
Dieback of European ash, caused by a fungus presumably introduced to Europe relatively recently, is threatening the tree on a continental scale. Norway represents the currently expanding frontier of the disease, and the aim of this proposal is to provide key information about ash dieback, the causative agent, genetic structure and disease resistance of Norwegian ash populations. No prior information is available about the genetic structure of Norwegian ash populations. Therefore, characterizing the present genetic resources, on a genome wide basis, and comparison with other European populations will provide us vital information to evaluate conservation efforts. By sampling primarily within the nature reserves present in Norway, the survey will yield valuable data for evaluation of migration and gene flow among these populations, as well as estimation of effective population size to avoid inbreeding within these fragmented populations. Danish field trials have implicated a genetic component in host resistance towards ash dieback. As there is clustering of relatives in many ash populations, we will also test if spatial variation in susceptibility to ash dieback is related to certain family groups. Identification of such superior families can be employed in breeding programmes. In addition the proposal includes molecular characterization of the causative pathogen and establishment of the host developmental stage and tissue through which the infection takes place. We will also develop a high-throughput diagnostic assay for detection of the fungus in diseased trees and propagation material. In cooperation with the Norwegian genetic resource centre, the data will be passed down to the management authorities to be used in developing sustainable management plans for ash in nature reserves in Norway. In conclusion, the project will contribute to maintenance of ash-associated biodiversity, sustainable management of ash stands and disease-free propagation of the tree.
Norway