Towards targeted breeding of a European SRC willow crop for diverse environments and future climates (BREDNET-SRC)

Lead Research Organisation: Rothamsted Research
Department Name: Agro-Ecology

Abstract

Short Rotation Coppice (SRC) willow (genus Salix) is amongst the most advanced second generation energy crops in temperate regions. Breeding and improvement of this crop has been significantly enhanced by underpinning with genetic and genomic approaches led by two independent leading programmes in the UK and Sweden. To further advance the crop, cultivars are needed that will grow on a wider range of environments and that are future climate proof. The research proposed here will increase the effectiveness of public research supporting the genetic improvement of willow for Short Rotation Coppice in Europe by combining the two leading efforts and targeting them towards these goals. It will do this by taking shared approach to the delivery of key underpinning research, developing and sharing key research and genetic resources, and by working proactively and collectively with stakeholders to deliver this research into practice. The research brings together Europe's leading publicly funded research based SRC willow genetic improvement and public breeding programme based at Rothamsted (UK) with the long-standing Swedish willow breeding effort at the Swedish University of Agricultural Sciences and at Uppsala; Lantmännen/Agroenergi AB as the premier private sector marketer of willow in Europe; and the expertise in phenotyping, science communications, innovation and policy interactions in Lower Saxony's Network for Renewable Resources (3N) in Germany. This consortium will deliver six interconnected research outputs: 1. The establishment of a new S. viminalis population comprising accessions of potential value across Europe from existing unique germplasm collections held by partners; 2. The deployment of association mapping methodologies to willow for the first time; 3. Building on and sharing existing research to identify candidate genes and polymorphic markers within the population; 4. Testing candidate genes and their alleles for associations with key productivty traits under a range on environments; 5. The analyse of existing public research outputs for relevance to the genetic improvement of willow across Europe; 6. The proactive engagement of key stakeholders, including the ERANET's funding authorities, to ensure delivery into practice so that the research provides a public legacy for efficient research in the future. In recent years, Swedish and UK breeding programmes, underpinned by molecular approaches, have made significant progress in terms of improving willow SRC. As SRC willow production increases across Europe, suitable cultivars for a range of contrasting environments will be required. This research will deliver understanding into breeding programmes (including partners' breeding programmes) about the genetic basis of yield in the context of different European environments. It will deploy association mapping methodologies in willow for the first time through which the measurable characteristics of genes in candidate clones are associated with clone performance in diverse environments. Phenotyping of the population across a range of contrasting European sites will be used to link beneficial traits to variation in genes and provide an understanding of yield in the context of diverse environments, including on marginal land and under conditions relevant to a warmed climate. The population and associated trait data will also provide a valuable, permanent resource for use within existing and future national research programmes enabling the efficiency and delivery of the ERANET's partners public research effort to be improved in the longer term.

Technical Summary

Genetic improvement programmes in Sweden and the UK have made significant progress in breeding Short Rotation Coppice (SRC) willow. However, to expand production, cultivars suited to wider range of European environments and future climates will be needed. The research will address this by delivering an understanding of the genetic basis of yield in the context of varied European environments into breeding programmes and provide molecular tools for selection. The research will focus on a Salix viminalis association mapping population generated from the unique germplasm resources held by Rothamsted Research and Swedish partners. After first assessing population structure in the germplasm, suitable material (~400 genotypes) will be planted at seven contrasting sites across Europe and key biomass-related traits will be assessed. Comparative trait data will be used in candidate gene-based association mapping to identify favourable alleles that will be delivered to breeding programmes for the development and deployment of molecular based selection strategies. Focus will be given to traits that are not yet well-studied in national programmes but are of importance, namely achievement of high biomass yield on marginal land and in conditions where water may be limiting. For growth on marginal land, novel microarray studies will be performed to identify candidate genes involved in this trait. To study yield in the context of future climate conditions, candidate genes for drought-related traits will be selected from our QTL and from the available literature. A similar approach will be taken for phenology traits. A significant component of the research comprises the analysis and transfer of existing research outputs to support this project and the development of willow in partner countries. Furthermore, active knowledge management and stakeholder interaction will ensure delivery into practice and provide an accessible legacy for efficient public research in the future.

Publications

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Description In willow, the main targets for improvement are pest and disease resistance and most importantly, high yield,even when planted on sites that would normally be considered poor for conventional agriculture. Climate change is also
likely to lead to a greater requirement for drought tolerance in some areas. All of these traits are complex and are governed by many genes and interactions with the environment, making breeding challenging. One way to improve breeding efficiency is to identify plants that carry beneficial versions of the important genes by examining their DNA in a process known as marker-assisted selection. However, as a prerequisite for this, we first need to identify regions of the genome that harbour the important genes. DNA-based tests to determine whether or not particular plants carry the optimal
versions of particular genes can then be developed. In this project, we aimed to identify the important genome regions by associating variation in growth traits with difference in the DNA sequences of about 360 different willow tree collected from across Europe. This population of trees was established at four field contrasting sites, two in the UK and two in Sweden, to provide information on how differences in the environment may also influence performance. By comparing key trait measurements made at the field sites throughout the project with differences in the DNA sequences of the different individuals, we successfully identified variations in 20 genes that were significantly associated with our target traits. These results will now be used to develop tests for marker-assisted selection in willow breeding programmes in the UK and Sweden.
Exploitation Route Directly - the genes can be selected for in breeding programmes to either increase or decrease the number of shoots that emerge after coppicing.
Sectors Agriculture, Food and Drink,Energy,Environment

 
Description 1. An extremely valuable and unique, permanent genetic resource was established for bioenergy tree research. The Salix viminalis association mapping population created comprises accessions from major European willow collections and new material from natural populations of the Czech Republic, Sweden and Poland. The population is characterised in terms of diversity and population structure and remains at four sites (two Swedish, two UK) where it underpins new aspects of gene discovery and molecular breeding research in both countries. 2. A database of phenotypic data was generated for key traits of importance to bioenergy trees. The multi-site nature of the project generated valuable new information on GxE interactions, phenotypic stability and a resource for future association studies. 3. Variation in several candidate genes, including novel loci highlighted by our transcriptomic studies, was shown to be associated with phenotypic diversity in phenology and architecture traits, providing markers for breeding and further biological insight.
First Year Of Impact 2013
Sector Agriculture, Food and Drink,Energy
Impact Types Societal,Economic