EFFECTS OF SHRUNKEN AND OTHER MUTATIONS ON THE PROPERTIES OF RICE ENDOSPERM STARCH

Starch granules were isolated from rice endosperms of twenty mutants, included two kinds of shrunken (shr) mutant, and two cultivars of thei r normal counterparts. The shr mutants, EM-20 and Kenkei 2088, showed opposite effects on the amylose content, that is, EM-20 had 5% higher than its normal counterpart and Kenkei 2088 had 3% lower than its one. The amylopectin of EM-20 was composed of slightly shorter chains on t he average than its normal one. The gelatinization temperature and hea t of gelatinization were affected by the mutation of shr, EM-20. The a mylose extender (ae) mutant, Kenkei 2064, had a comparable amylose con tent with its normal counterpart but its amylopectin had higher conten t of long chain than the normal one. Twelve kinds of dull (du) mutant reduced the amylose content which varied from 2% to 16%.