IMG_0967
One of the Hordeum spontaneum parents of the Barley NAM population

Delivering sustainable food production in the face of climate change requires a revolution in breeding crops that deliver high and sustainable yield under fluctuating disadvantageous environmental conditions. The ancestral wild germplasm of modern crops contains allelic variants that can achieve this goal, yet modern crops are becoming increasingly depleted in biodiversity. The two key obstacles to successful exploitation of wild germplasm are finding the wild‐derived alleles needed and testing them in the field.

IMG_0916
Barley NAM population at JHI in 2015. Concerto is the control strip on the RHS
IMG_1003
Some lines just want to keep photosynthesising whilst the majority are senescing

The BARLEY‐NAM project is using wild barley (Hordeum vulgare ssp. spontaneum) as a model and apply novel genomic and breeding tools to improve agronomic performance of elite barley under abiotic and biotic stresses. For this, we are applying the nested association mapping (NAM) approach using the first cereal NAM population, HEB‐25. HEB‐25 comprises 1,420 BC1S3 lines, sub‐divided into 25 families, originating from crosses of the elite barley cultivar Barke with 25 different wild barley donors. The HEB‐25 lines will first be assessed for allele content at 21,643 genes (every known highconfidence barley gene), employing state‐of‐the‐art exome capture and next generation sequencing. We expect to map roughly 400,000 SNPs within HEB‐25 giving unprecedented levels of gene and genome resolution for barley. Second, all HEB lines have been cultivated in field trials in Germany, Scotland and Israel for harvest years 2014 and 2015 to assess agronomic performance under nitrogen deficiency, drought and pathogen attack. Yield components and nutrient content are being scored, as well as resistance against the major barley diseases leaf rust, yellow rust and net blotch. In addition, agronomic performance will be modelled by non‐invasive remote sensing technology to establish phenotype predictions. Third, the collected data sets will be archived and further processed in a central data warehouse, built around a custom web‐accessible relational database. Fourth, genotype and phenotype data of HEB‐25 will be combined in a genome‐wide association scan (GWAS) to identify wild barley alleles that improve plant performance under stress. Since the gene resolution is extremely high, this study will yield individual high confidence candidate genes that putatively regulate the studied traits. Fifth, to validate the identified trait‐improving exotic alleles, segregating high‐resolution progeny will be developed from the HEB lines.

The BARLEY‐NAM project will be beneficial in two directions. On the one hand, the genes and gene variants regulating agronomic traits in barley will be defined at a level of detail unprecedented for the crop and this will inform future strategies for parallel improvement in wheat and rye. On the other hand, trait‐improving wild barley alleles will be available for application in future barley breeding. This will lead to new barley cultivars with improved performance and extend the biodiversity and sustainability of the elite barley gene pool.

 
For further information on this project please contact Andy Flavell (a.j.flavell@dundee.ac.uk), Bill Thomas (bill.thomas@hutton.ac.uk) or Hazel Bull (hazel.bull@hutton.ac.uk) from the James Hutton Institute / University of Dundee.