Comparison of American and European maize (Zea mays L.) protein profiles

Maize is an important crop with great use in agriculture, food and other industries. The aim of this work was to compare 30 varieties of Zea mays L., that were grown in the USA and Europe in terms of nutritional quality and to genetically distinguish them by creating a dendrogram of relationship. The content of total nitrogen, crude protein content, fractional composition of proteins and the calculated coefficient of nutritional quality were all determined. Compared to American varieties, higher nutritional quality was shown by the varieties of European origin with the coefficient of nutritional quality higher about 17.55%. However, the highest value was achieved by the American variety Howling Mob (331.91%). Storage proteins - glutelins were divided according to molecular weight into HMW-GS (high molecular weight glutelin subunits), LMW-GS (low molecular weight glutelin subunits) plus zeins and residual albumins and globulins by electrophoretic separation. The biggest difference was recorded among HMW-GS content - 5.77% (American varieties) and 7.35% (European varieties), while the LMW-GS plus zeins and residual albumins and globulins content was similar. 20 protein bands (15 polymorphic and 5 monomorphic) in American varieties and 18 protein bands (10 polymorphic and 8 monomorphic) in European varieties were evaluated in the electrophoretograms. Based on the presence of individual proteins, a dendrogram was constructed, using the UPGMA (Unweighted Pair-Group Method Using Arithmetic Averages) method and the Jaccard coefficient of similarity. In the dendrogram, 2 clusters of varieties with the dissimilarity 0.481 were formed. In the subgroups, from the point of glutelin polymorphism, the varieties Illinois Hulles and Queen Anna were separated from the others. The European varieties were segregated within the second cluster and created the common subgroup of 2 varieties - Madarska cukrova (Hungary) and Zlota Handlowa (Poland).