The general topic of research is the analysis and exploitation of natural genetic diversity in cereals, mainly barley and wheat. This comprises genetic mapping of single genes as well as quantitative traits (QTL), map-based cloning, analysis of genetic diversity based on molecular marker analysis and analysis of haplotypes based on DNA-sequencing. Several marker systems are in use, such as microsatellites, also called simple sequence repeats (SSRs), and SNP-markers (‘single nucleotide polymorphism’).

The advanced backcross strategy was employed to map quantitative characters (QTL) for agronomically important traits, such as yield, plant height, grain weight, grain number, days to flowering etc. in various backcross populations of barley and wheat (Huang et al. 2003; Huang et al. 2004; Li et al. 2005). For heritable QTLs nearly isogenic lines (NILs) with defined introgressions are developed by further backcrossing which allow the dissection of QTLs into single Mendelian genes. This strategy enables to dissect complex traits which are inherited by several genes into their single components for a further detailed molecular analysis. As example, a QTL for 1000-grain weight in wheat could be dissected into a single Mendelian gene (Röder et al. 2008) and is now subject of a map-based cloning approach.

Scald is a fungal disease in barley caused by Rhynchosporium secalis with economic importance in temperate climate. The resistance gene Rrs2 from the barley variety ‘Atlas’ was finemapped in a progeny of 9000 individuals on the short arm of chromosome 7H. A BAC contig for the respective genomic region was constructed by exploiting the synteny to rice chromosome 6. The sequencing of genomic fragments from varieties with and without Rrs2 led to the development of diagnostic molecular markers, which can be used selection of Rrs2 in breeding programs.

Apart from yield, malting quality is the most important trait in any spring barley breeding program. Despite its salient importance, the quantitative inheritance exacerbated a detailed genetic analysis on the structural level. The project GABI-malt is part of an integrated approach to the genetic and functional dissection of malting quality in barley. The main objective was to determine haplotypes of genes coding for key enzymes involved in the malting process and of ESTs with differential expression during malting. Their genetic contribution to the malting and brewing properties was evaluated by correlation of haplotype data to phenotypic data from micromalting in a selected set of barley varieties. It was possible to find genes associating to malting  parameters and to develop molecular high throughput markers.

In the follow-up project GABI-GENOBAR this approach is continued with further candidate genes and association mapping of agronomic traits.

In a concerted action of several groups at the IPK the genetic factors underlying seed development were dissected by various approaches within the project GABI-Seed II. The project is based on a population of barley introgression lines with defined chromosomal fragments of the wild barley species Hordeum spontaneum. This population served as the base material for transcriptome, proteome and metabolite profiling at four different time points after fertilisation. The analyses were conducted by the groups ‘Gene Expression’, and ‘Applied Biochemistry’ at the IPK. Putative transcription factors which are potential regulators during seed development were mapped on this population as SNP-markers. Furthermore, ESTs with differential expression which were identified by the group ‘Gene Expression’ were placed on the introgression lines. In the combined analysis of expression profiles of RNA, proteins and metabolites each profile was treated as a quantitative phenotype and calculated as a  quantitative trait loci (QTL). With the approach termed 'genetical genomics' QTLs  that affect the expression profiles either as cis- or as trans-acting factors were mapped in order to unravel the genetic networks underlying seed development. 

Based on these results, the follow-up project GABI-grain investigates the impact of drought stress on the regulatory networks of seed development. Lack of water during the seed filling phase can result in a derangement of the sink-source relations and  have an impact on kernel size and total yield. Our aim is to develop barley lines with improved tolerance to drought stress during seed development.