[SSR polymorphism on the waxy gene locus and their relationship to amylose content in wheat]

Variation of one simple sequence repeat (SSR)(AT (AT)n AT) in the 3 end of the waxy gene was analyzed in samples of 32 cultivars, including different wheat cultivars in Shandong region and representing a wide distribution range of amylose content (AC) in cultivated wheat. In this study, we found two fragments were present in all cultivars, one of 204bp, the expected size, and one of 225-346bp. 204bp fragment located on the chromosome 7DS, while 225-346bp fragment located on the chromosome 7AS. That is, Wx-Ala gene and Wx-Dla gene present in all wheat lines, but the larger fragment showed length polymorphism. The result showed that the amylose level is highly positive correlated with the length of the polymorphic SSR. Amplified fragment is long in high AC cultivars and electrophoresis migration rate is small, while the fragment is short in low AC cultivars and electrophoresis migration rate is large. AC is highly diverse among different lines with the various SSR genotypes. Although the SSR variation did not seem to have obvious function in the synthesis of the starch synthase encoded by the waxy gene, the correlation between the SSR and AC level could be used as molecular marker for quality improvement in wheat programs.