Screening and identification of rice non-floury endosperm mutants with different starch components

Starch components determine rice quality and utilization. Rice floury endosperm grains have poor quality. In this study, we screened 27 non-floury endosperm mutants with different starch components from a mutant population derived from japonica rice variety Nipponbare using urea gelatinizing grain-iodine staining method. Nine mutants of MY03, MY12, MY16, MA06, MA15, MP09, MP20, MP31 and MP40 were chosen for identification of homozygous mutant and analysis of starch components and grain properties. The amylose content in single grain indicated that the screened mutants were homozygous and the stained solution color of gelatinized grain could reflect the starch components of brown rice grain. The MY03, MY12 and MY16 grains had altered amylopectin structures and exhibited high gelatinization temperatures and strong resistances to urea gelatinization. Compared with Nipponbare grains, MA06 and MA15 grains had very high amylose and lipid contents. The MP09, MP20, MP31 and MP40 grains had significantly lower amylose contents than Nipponbare grains. The screened mutants had similar grain transparency to Nipponbare. This study provided a method reference for rapidly screening rice non-floury endosperm mutants from thousands of mutant lines, and the screened mutants were important genetic materials for revealing starch synthesis and regulation and good germplasm resources for rice quality breeding.