The potential for field studies and genomic technologies to enhance resistance and resilience of British tree populations to pests and pathogens

Abstract

Genetic research on the interactions of temperate tree hosts with pests and pathogens, and breeding for resistance or low susceptibility, are hindered by the long generation time and large size of tree species. Foresters need to be quick to exploit new technologies that may accelerate research and breeding programmes, and opportunistic in gaining maximum use from existing experimental tree plots. A fruitful approach may be to apply new genomic methods to the analysis of established provenance and progeny trials, seed orchards and clonal archives, where screening for pests and pathogens may occur. An important test case of this approach is underway in Britain with respect to ash (Fraxinus excelsior L.) and the search for resistance to the dieback caused by Hymenoscyphus fraxineus (T. Kowalski) Baral, Queloz, Hosoya, comb. nov. This review examines: (1) the use of field trials for pathogen and pest resistance in forest trees, (2) how field trials may support the application of genomic technologies to tree health issues, (3) the extent of the field trial resource in Britain, (4) issues that constrain the use and maintenance of field trials, (5) an outline of possible experimental designs, (6) the use of natural systems and (7) funding of long-term trials. Application of the latest technologies may be critically dependent on the availability of welldesigned and maintained, long-term, field trials that produce invaluable resources and results for decades.