Discrimination between some Chinese and Yugoslav winter wheat cultivars by capillary electrophoresis of gliadins

Gliadin proteins extracted from seventeen China and Yugoslav winter wheat cultivars were separated by capillary electrophoresis (CE). In order to optimise resolution and reproducibility of gliadin separations, different CE conditions, including capillary length, internal diameter, temperature and voltage, were investigated. Excellent resolution and high reproducibility of gliadin CE patterns were obtained by using a 47 cm length, 50 μm i.d. capillary at 15 kV and 30°C in 0.06 M sodium borate buffer (pH 9.0), containing 20% acetonitrile (ACN) and 1% sodium dodecyl sulphate (SDS). Using these conditions, gliadin electrophoregrams of all cultivars studied showed clear qualitative and quantitative differences, including peak numbers, heights and positions. In particular, some closely related cultivars that were not differentiated by acid polyacrylamide gel electrophoresis (A-PAGE, pH 3.1) were readily differentiated by CE. These results demonstrate the great potential of CE as a new technique for crop varietal identification and seed purity testing.