HIGH-LYSINE MUTANTS OF RICE, ORYZA-SATIVA L

In order to improve the nutritive value of rice protein, it is necessa ry to increase the level of lysine and threonine. Ten high-lysine muta nts were selected from N-methyl-N-nitrosourea-induced (MNU-induced) mu tant lines, using high-performance liquid chromatography for amino aci d analysis. The lysine content of these mutants ranged from 5.10% to 6 .38% of total amino acids, while that of the original varieties was ab out 4%. All high-lysine mutants also had a greatly increased histidine content and a floury endosperm. An increase in lysine content of the albumin/globulin fraction was characteristic of the MNU-induced high-l ysine mutants. The segregation ratio of normal to floury endosperm in the FZ seeds from a cross between 'Kinmaze' and a high-lysine mutant f itted the expected 3:1 ratio. The high level of lysine and the floury endosperm may be controlled by the same gene.