The use of floury endosperm mutants to develop rice cultivars suitable for dry milling

Starch is the major constituent of rice grains determining eating, cooking, and processing properties. While rice endosperm mutants with modified starch characteristics have provided valuable materials for elucidating the gene mechanisms involved in starch biosynthesis and grain development, their practical use in crop improvement has been rarely documented. In this review, we focus on the use of floury endosperm mutants with reduced grain hardness to breed rice cultivars suitable for dry milling. We describe the identification of “Suweon542”, the original genetic source carrying flo4-4 [formerly flo7(t) ] which has been used to develop Korean rice cultivars specialized for dry-milled flour production. Molecular breeding efforts are highlighted in the development of “Garumi1” and “Garumi2”, the floury endosperm rice cultivars with improved agronomic characteristics.