Hordeum bulbosum - Genetic Resources for Barley Crop Improvement Revisited

We explored the usefulness of Next-Generation-Sequencing technology for developing and scoring molecular markers in diploid introgression lines (IL) of cultivated barley (Hordeum vulgare L.) containing chromatin from its wild relative Hordeum bulbosum L..

We used a recently developed whole exome capture assay in combination with a custom SNP genotyping assay as well as two-enzyme genotyping-by-sequencing (GBS) to allocate the introgression interval of a H. vulgare/H.bulbosumIL and to genotype progeny segregating for the introgression. Both methods provided fast and reliable detection and mapping of the introgressed segment and enabled the identification of recombinant plants avoiding tedious and iterative steps of marker development.

In a subsequent study GBS was applied to characterize 141 barley/H. bulbosum ILs by looking at H. bulbosum specific SNP frequencies along the barley reference map. H. bulbosumsegments could be identified on all chromosomal arms and even very small (< 1 MB) introgressed fragments could be detected and localized with about 8 and 9 SNPs per 1 MB or 1 cM, respectively. In fact, 13 ILs displayed additional introgressed segments, which haven’t been identified by previous attempts.

Furthermore, two diploid H. bulbosum F1 mapping populations were developed and genotyped with GBS to generate an integrated high density genetic which will be utilized to study in greater detail vulgare/bulbosum genome colinearity to reach also a better understanding of the structure of the introgressed bulbosum genome segments.