Development of a scar marker for the Ph1 locus in common wheat and its application

To facilitate wheat breeding with the Ph1 gene, 19 sequence tagged-polymerase chain reaction (STS-PCR) primers developed previously from barley chromosome 5H were screened. One pair of STS-PCR primers differentiated 'Chinese Spring' (CS, Ph1) and the CS mutant (ph1b). The diagnostic fragment was 920 base pairs (bp) in size, designated as ABC(920), and was located on the interstitial deletion of the long arm of chromosome 5B of ph1b mutant. Plants with or without the Ph1 gene could be distinguished among 148 F-2/97 BC1 plants from the cross CS (Ph1) x CS mutant (ph1b) on the basis of the presence or absence of this fragment. Subsequently, two 24-mer sequence characterized amplified regions (SCAR) primers were developed on the basis of sequences at both ends of the ABC920 fragment to generate a single amplified band in plants with the Ph1 genotype. The Ph1 and ph1b genotypes can be readily scored in the PCR products of individual plant DNA. This SCAR marker (SCABC(823)) was used to facilitate the transfer of the ph1b locus into an elite wheat (Triticum aestivum L.) cultivar. This marker is expected to aid in gene transfer between wheat and its wild relatives.