BARLEY CULTIVAR IDENTIFICATION BY ELECTROPHORETIC ANALYSIS OF HORDEIN PROTEINS: I. EXTRACTION AND SEPARATION OF HORDEIN PROTEINS AND ENVIRONMENTAL EFFECTS ON THE HORDEIN ELECTROPHOREGRAM

Reproducible hordein electrophoregrams were obtained when hordeins, extracted from Canadian-grown barley cultivars, were subjected to polyacrylamide gel electrophoresis at acid pH (acid-gel PAGE). The hordeins were extracted at room temperature into a solution of 55% (vol/vol) isopropanol containing 2% (vol/vol) monothioglycerol. Extraction of hordein at high temperature (60 °C) produced significant reduction in the number of protein bands available for cultivar identification. Alkylation of the reduced hordeins, prior to acid-gel PAGE, did not improve the resolution or appearance of the hordein electrophoregrams. The effect of environment on the hordein electrophoregram was studied. Four barley cultivars were grown at eight locations in Western Canada during 2 successive years. Hordein electrophoregrams were qualitatively independent of growth location, year of growth and protein content. These results suggest that acid-gel PAGE should prove useful as a technique for barley cultivar identification.