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%.