About (The Exotic Bread Wheat and Landrace Pillar)
Objectives
1. Multiplication and curation of exotic bread wheat germplasm collections for use across the programme.
2. Contribution to primary phenotypic screens of germplasm collections.
3. Mining of novel alleles for genes of known function.
4. Production of segregating populations (25 each year) for lines of interest identified in primary germplasm screens.
5. Use existing landrace x elite segregating populations to identify QTL controlling traits of interest.
6. Production of Near Isogenic Lines for prioritised QTL and genotypically defined allelic variants.
7. Assessment of agronomic performance of Near Isogenic Lines.
8. Development of informative genetic markers for marker assisted selection in commercial wheat breeding programmes.
9. A relational database for full public access to data generated.
The genomes of modern, elite bread wheat varieties are mosaics of chromosomal segments originating from wheat lineages (land races) that arose during the 10,000 years separating the domestication of hexaploid wheat and the birth of modern plant breeding. As plant breeding progressed through the 20th century, quantitative genetic gain was increasingly achieved through the deployment of already selected alleles into new combinations. This is a very efficient approach for the fine tuning of germplasm for a specific set of environments. However, the search for new and useful allelic variation outside of adapted germplasm is challenging for commercial wheat breeders. This is an essential element of any strategy for continuance and consolidation of the genetic gains achieved for UK wheat, as well as an opportunity to arm UK wheat breeders with alleles that will facilitate adaptation to new environmental challenges: reduced nitrogen inputs; drought; thermal stress; and new pests and diseases. This project will hopefully provide greater resilience and flexibility for the existing academic to commercial genetic pipeline for UK wheat breeding.
Physiological, agronomic, and breeder’s models of mechanisms underlying target traits will guide extensive phenotypic screens of landrace and non-adapted germplasm collections. This is a scoping exercise for the extent of variation available. It will guide the selection of parents for the development of segregating populations in which the genes controlling traits of interest will be characterised as quantitative trait loci (QTL). Potentially useful alleles will be introgressed into a set of elite genetic backgrounds so that their value for breeding can be assessed against the best existing varieties. This work will deliver pre-breeding germplasm for UK varietal improvement within the WISP project and also to world wheat breeding. It will test and guide modification of the physiological models driving this programme. The genetic materials produced, together with associated phenotyping and genotyping inputs from other WISP work packages, will facilitate the positional cloning and elucidation of molecular genetic mechanisms underlying these key traits via ‘uplift’ activities.
The ultimate outcome of this work, together with the UK existing wheat genetics and physiology programme, will be sustainable genomics led predictive wheat breeding in the UK.
Research Programme
Sources of new genetic variation in hexaploid germplasm: The UK wheat genetics community has made a long term investment into four germplasm collections that are highly suited to the objectives and scale of the work proposed here. 1) The AE Watkins Collection comprises 831 land race accessions collected from thirty three countries in the 1920s and 1930s. The collection of Watkins samples, prior to the introduction of improved varieties in these countries eliminates the possibility of contamination from modern wheat varieties and provides a genuine snapshot of global wheat germplasm prior to systematic inter-crossing and selection. As part of the Defra funded Wheat Genetic Improvement Network (WGIN http:www.wgin) each accession has been genetically fixed. Moreover, data for a number of traits including height, heading date, grain shape, glutenin composition, foliar disease, growth habit, and morphology have been collected. Over twenty single seed descent (SSD) populations are under development. 2) The Gediflux Collection was assembled as a JIC contribution to an EU FP6 project. It comprises over 500 Western European winter wheat varieties that individually have occupied over 5% of National acreage from 1940 onwards. 3) A collection of lines with extreme phenotypes largely collected by John Snape and the late Tony Worland at JIC. 4) Non UK parents of existing mapping populations that can be used for the identification of QTL. An example of this type of material would be the key CIMMYT varieties Weebil, Bacanora, Milan and Catbird. JIC has already produced doubled haploid (DH) populations and genetic maps for these varieties and identified QTLs for a wide range of traits in diverse environments.
As the programme progresses new sources of genetic diversity will be identified and multiplied for characterisation beyond the three years of research proposed here.
