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

Background and Objective: Aside from its various biomedical effects, γ‐oryzanol is a biomarker for heat stress in rice (Oryza sativa L.). Recently, we found that a japonica cultivar Momiroman had the highest γ‐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 γ‐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 γ‐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 γ‐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 γ‐oryzanol in the indica genetic background. Significance and Novelty: This study revealed the QTLs for the concentrations of 1, 2, and/or total γ‐oryzanol on chromosomes 4, 5, 9, and 11, providing essential information for the development of cultivars with specific biomedical properties or heat stress resistance. [ABSTRACT FROM AUTHOR]