Barley allele-specific amplicons useful for identifying wheat-barley recombinant chromosomes

Barley (Hordeum vulgare L.) is potentially a new source of genes for wheat (Triticum aestivum L.) improvement. Wheat-barley chromosome recombinant lin es provide a means for introgressing barley genes to wheat genome by chromo some engineering, and since these are expected to occur only rarely in spec ial cytogenetic stocks, an efficient selection skill is necessary to identi fy them. To convert RFLP markers to barley allele-specific PCR markers usef ul for effective production of wheat-barley recombinant lines, 91 primer se ts derived from RFLP clones which were previously mapped to the barley chro mosomes were examined for PCR amplification using 'Chinese Spring' wheat, ' Betzes' barley and the wheat-barley chromosome addition lines. The polymorp hisms were detected by an agarose gel electrophoresis of the PCR products w ithout digestion with restriction enzymes. Out of 81 primer sets producing polymorphisms between the wheat and barley genomes, 26 amplified barley chr omosome-specific DNAs which were confirmed to be located on the same chromo some as the RFLP markers by using the wheat-barley chromosome addition line s. These amplified DNAs represent barley allele-specific amplicons, which d istinguish barley alleles from their wheat homoeologous counterparts. The p resent investigation revealed a higher probability for obtaining allele-spe cific amplicons from genomic DNA-derived RFLP markers than from cDNA-derive d ones. The barley allele-specific amplicons developed in this study, namel y, four for chromosome 2H, two for 3H, seven for 4H, eight for 5H, one for 6H and four for 7H, are suitable for identifying 'Chinese Spring' wheat- 'B etzes' barley recombinant chromosomes. However, one out of eight barley all ele-specific amplicons on chromosome 5H did not detect a unique barley band in a 'New Golden' barley chromosome 5H addition line of 'Shinchunaga' whea t, indicating there may be a need to reconstruct allele-specific amplicons with different barley cultivars.