Inheritance and improvement of protein quality and content in maize; annual report, 1976/1977

DURATION: April 1975-March 1978. DEVELOPMENTS: The project is screening for new high-lysine mutants and identifying problems associated with acceptance of high lysine maize through an interdisciplinary and cooperative approach. A group of 55 collections of maize from the world germplasm bank have been screened for potential higher lysine with the ninhydrin test. Lysine content of positive reacting kernels was at the normal level but protein showed a tendency toward higher levels. Two low lysine-high protein populations and two high lysine-low protein populations were fractioned using the Landry and Moureaux method. The extreme difference in lysine content was strictly a function of varying amounts of protein present in the various fractions. Lysine content in the various fractions was not changed by selection. Developmental studies are in progress to determine the interactions of genotype on germ and endosperm storage and compensation effects involved in constraints to yield, protein, starch, and oil accumulation in the kernel. Two varieties adapted to the more temperate areas have been developed from diverse germplasm. Selection for improved agronomic and nutritional characteristics is being conducted in opaque-2 and sugary-2 opaque-2 versions of these two varieties. The variety Colus from Colombian and U.S. germplasm has been converted to opaque-2 and is undergoing selection. Maize is a particularly efficient crop species and with improved protein quality and agronomic characteristics can play an increasing role in solving the world"s human and animal nutrition problems.