A polymorphic microsatellite in the 3 ' end of 'waxy' genes of wheat, Triticum aestivum

Potential polymorphism of an (AT)(n) microsatellite at the 3' end of waxy g enes in bread wheat was examined. Primers were designed from a published cD NA sequence of a wheat waxy gene. Polymerase chain reaction (PCR) amplifica tion of genomic DNA from 135 mainly Australian cultivars revealed eight all eles on chromosome 7A. This polymorphic microsatellite is a potential codom inant marker for the Wx-A1 locus in breeding programmes. A distinguishable fragment was also amplified from chromosome 7D. This fragment was absent wh ere a plant was null for the waxy gene on chromosome 7D, being a dominant m arker for the Wx-D1 locus. The primers were also useful for amplifying geno mic DNA from barley, rye and triticale and can be used to detect potential polymorphism in these species.