Prediction of durum wheat quality from electrophoretic and high-performance liquid chromatography pattern of gliadins

Gliadin proteins of twenty five durum wheat varieties of diverse origins have been extracted with 70\% ethanol and analysed by both acetic acid polyacrylamide gel electrophoresis (AA-PAGE) and reversed-phase high-performance liquid chromatography (RP-HPLC) techniques. Based upon the established unbroken relationship between electrophoretic gamma-gliadin bands 45 or 42 with gluten strength or weakness, respectively, the studied varieties have been classified into high (type-45) and low (type-42) quality varieties. Four chromatographic peaks designated P1, P2, P3 and P4, eluted at retention times of 38, 39, 43 and 49 min, respectively, could be used to classify durum varieties into two groups in a way analogous io that in which electrophoresis may be used. This classification depends on the presence or absence of RP-HPLC peaks, namely P3 that corresponds to PAGE 42-gamma gliadin band, and peaks P1, P2 and P4 that correspond to 45-gamma gliadin band. However, only the relative areas of peaks P1 and P3 were highly correlated with durum quality (r = 0.68{*}{*}{*} and -0.89{*}{*}+, respectively), suggesting that they correspond to PAGE gamma-gliadin bands 45 and 42, respectively. Therefore, and because of its convenience and rapidity, RP-HPLC can be recommended as an analytical procedure alternative to electrophoresis for predicting quality and screening for durum varieties with unacceptably weak gluten characteristics when large numbers of samples must be analysed, as in early generations of wheat breeding programs.