The effect of varying nitrogen supply on the protein composition of a high lysine mutant of barley

Amino acid analyses of the grain of barley cultivars Risø 1508, Hiproly and Maris Mink carried out using grain of comparable protein levels have shown that the amino acid composition of Risø mutant 1508 is fundamentally different from that of the other varieties. A high proportional content of lysine and other nutritionally essential amino acids in Risø 1508 is achieved mainly at the expense of large decreases in glutamic acid and proline. Furthermore, a high lysine content in Risø mutant 1508 was maintained when the level of grain protein was raised by increasing the supply of nitrogen fertiliser.