A PCR-based DNA marker for detection of mutant and normal alleles of the Wx-D1 gene of wheat

To assist waxy wheat breeding a DNA marker was developed to discriminate mu tant and normal alleles at the Wx-D1 locus. This polymerase chain reaction- based marker distinguishes the mutant from the normal allele by targeting t he previously reported deletion basis of the mutant. The marker codominantl y identifies the normal allele of the Wx-D1 gene from the mutant allele ori ginated from the Chinese landrace 'Baihoumai'. However, attempts with a num ber of primer combinations targeting this deletion failed to amplify the co rresponding fragment from an unrelated wheat line (NP150) that has a mutant null allele at the same locus. This indicates that NP150 has a different m utant allele from that of 'Baihoumai'. This marker is a useful tool to iden tify wheat cultivars with mutant and normal alleles of the Wx-D1 gene, and is used in marker-assisted selection of the Wx-D1 gene in our waxy wheat br eeding programme.