Quantitative trait loci regulate the concentrations of steryl ferulates in brown rice

Background and objectives gamma-Oryzanol and its major components, 24-methylenecycloartanyl ferulate and cycloartenyl ferulate, which are distributed in the rice bran layer, exert biomedical effects. The objective of the present study was to detect QTLs regulating the concentrations of 24-methylenecycloartanyl ferulate and cycloartenyl ferulate by using the reciprocal CSSLs derived from a cross between an indica-type cultivar Takanari and a japonica-type cultivar Koshihikari, having low and high concentrations, respectively. Findings Conclusions We detected QTLs for the concentrations of gamma-oryzanol and 24-methylenecycloartanyl ferulate (mu g/grain and/or mg/kg) on chromosome 5 and the concentrations of cycloartenyl ferulate (mu g/grain and/or mg/kg) on chromosomes 4 and 11 in reciprocal genetic backgrounds. The concentrations were increased by the Koshihikari allele but decreased by the Takanari allele. In addition, we found a QTL for cycloartenyl ferulate concentration (mg/kg) on chromosome 2 in reciprocal genetic backgrounds. Interestingly, unlike the QTLs on chromosomes 4, 5, and 11, the concentrations were decreased by the Koshihikari allele but increased by the Takanari allele. The favorable alleles from japonica-type cultivars can be used to improve the lower concentrations of gamma-oryzanol, 24-methylenecycloartanyl ferulate, and cycloartenyl ferulate in indica-type cultivars. In addition, the favorable alleles from indica-type cultivars can be used to further increase the higher concentrations of cycloartenyl ferulate in japonica-type cultivars. Significance and novelty The QTLs detected in this study should contribute to future-breeding programs can enhance the health benefits conferred by rice.