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Quality protein maize (QPM) is high lysine (tryptophan) maize with hard endosperm and good agronomic performance. QPM was developed primarily for utilization in tropical and sub-tropical regions where maize is a staple food. Its adaptation and cultivation in temperate areas is still not fully developed, although QPM could have merits for production and consumption in developed parts of the world, especially as animal feed. Maize Research Institute Zemun Polje has a program on developing QPM genotypes for growing in temperate regions. The objective of our research was initial screening of 72 hybrids (derived from crosses between QPM lines adapted to temperate environments and three commercial lines with standard kernel quality) for kernel modification, tryptophan and protein contents, quality index (QI) and grain yield. Five hybrids with high tryptophan content (0.071 to 0.081%) and yield at the level of standard hybrids (96 - 114%) were identified. Protein content ranged from 10 to 11.20%, similar to standard hybrids. QI was in the range from 0.71 to 0.74, which was better than in standard hybrids (0.57 - 0.62), but below the QPM threshold of 0.80. The percentage of good kernel modifications (type 1 and 2) was over 80% in three and over 74% in two hybrids. The results indicated the complexity of obtaining high yielding hybrids with high levels of essential amino-acids. Identified potential QPM hybrids have to be further evaluated for agronomic traits, but the results can be considered important in the context of limited information on QPM adapted to temperate environmental conditions.

Since the mid 1960's, when the Maize Research Institute "Zemun Polje" began its maize breeding activities, there have been five cycles of selection primarily referring to the period of introducing new, higher-yield hybrids into mass production. This paper provides genetic characterization Of 30 maize hybrids developed by the Maize Research Institute "ZenlUn Polje", by RAID markers, in order to determine genetic relatedness of hybrids of different breeding cycles. The Jaccard similarity coefficients have been Computed and used for Cluster analysis by UPGMA and by Wards' method, discriminant analysis and correspondence analysis. Cluster analysis clearly delineates groups of hybrids by time cycles, while the correspondence analysis indicates that a division into three cycles Could be more adequate. The territorial map of the discrimination area, reduced to two dimensions, is an indication of the proximity between the cycles III and IV. Also the proximity of group centroids, of different cycles, by delineation lines indicates that the discrimination among groups is not so strong. The results Of all three analysis indicate that in genetic terms there -,ire three different selection cycles. Introduction of novel germ plasma into existing breeding material implies, in genetic terms, a beginning of new selection cycle.