Identification of quantitative trait loci for -oryzanol concentration using a cross between cultivars with extremely high and low -oryzanol levels

Background and Objective: Aside from its various biomedical effects, gamma-oryzanol is a biomarker for heat stress in rice (Oryza sativa L.). Recently, we found that a japonica cultivar Momiroman had the highest gamma-oryzanol among 92 cultivars. In the present study, we aimed to detect the quantitative trait locus (QTLs) for the concentrations of cycloartenyl ferulate (1), 24-methylenecycloartanyl ferulate (2), and total gamma-oryzanol in the populations from a cross between Momiroman and an indica cultivar Takanari. Findings: We detected the QTLs for the concentrations of 1, 2, and/or total gamma-oryzanol on chromosomes 4, 5, 9, and 11. The Momiroman alleles at the QTLs on chromosomes 4, 5, and 11 increased the concentrations of 1, 2, and/or total gamma-oryzanol, whereas the Takanari alleles at the QTLs on chromosome 9 increased. Conclusion: Considering the literature data, the japonica alleles at the QTLs on chromosomes 4, 5, and 11 may increase the concentrations of 1, 2, and/or total gamma-oryzanol in the indica genetic background. Significance and Novelty: This study revealed the QTLs for the concentrations of 1, 2, and/or total gamma-oryzanol on chromosomes 4, 5, 9, and 11, providing essential information for the development of cultivars with specific biomedical properties or heat stress resistance.