Biochemical and agronomic performance of quality protein maize hybrids adapted to temperate regions

Abstract

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.