Allele mining in wild barley: finding new exotic genes which control flowering time in the barley nested association mapping (NAM) population HEB-25 (DFG-Schwerpunkt SPP1530)

The nested association mapping (NAM) design was recently implemented in maize to tap into the wealth of genetic diversity which is available for modern crop species. A major first application of the NAM design was reported by Buckler et al. (2009), who dissected the genetic architecture of flowering time (FTi) into quantitative trait loci (QTLs) using a set of 5,000 maize NAM lines.

During the course of the project, we aim to use the NAM design to explore the genetic diversity for FTi in wild barley. For this, we have developed the barley NAM population HEB-25, consisting of 1,500 BC1S3 lines. HEB-25 originates from crosses of the barley cultivar Barke with 25 highly divergent wild barley accessions. For genetic characterization, the NAM population will be genotyped with 9,000 Infinium SNPs plus selected candidate genes with known function in FTi control. For phenotypic characterization, the HEB-25 lines will be grown in greenhouses and in the field where life history traits will be recorded manually. Simultaneously, we plan to develop an automatic, non-invasive, high-throughput system to measure FTi behavior. We aim to overcome the limitations of manual phenotyping by automatic data acquisition and interpretation based on 3D image analysis techniques in high temporal resolution. We expect that the techniques developed will also substantially advance high-throughput phenotyping in general.

After genotype and phenotype data have been collected, both data sets will be joined in order to carry out an association genetics screen to localize new wild barley QTLs which are associated with the expression of FTi. The new exotic QTL alleles will help to broaden the genetic diversity which is present in our elite barley gene pool. Simultaneously, the exotic QTL alleles will shed further light on the genetic network of FTi control in cereals.