Identification of Quantitative Trait Loci Affecting Grain Fat Content in Rice (Oryza sativa L.)

Fat content (FC) partially determines rice grain quality. The objective of this study was to identify stably expressed quantitative trait loci (QTL) for FC. A total of 85 inbred lines derived from the backcross between Sasanishiki (japonica, as the recurrent parent) and Habataki (indica) were used to detect QTLs for rice fat content. Seven QTLs (denoted as qFC-1, qFC-2, qFC-3, qFC-6, qFC-10, qFC-11, and qFC-12) were detected on chromosomes 1, 2, 3, 6 10, 11, and 12, respectively, using inclusive composite interval mapping (ICIM) method. Among them, three major QTLs (qFC-3, qFC-6, and qFC-11) with large effect were further confirmed across two different environments using some chromosome segment substitution lines (CSSLs), where Habataki was used as the donor parent and Sasanishiki as the recurrent parent. Further experiments showed that one of the major QTLs (qFC-11) could increase fat content, fat index, and grain yield together. To our knowledge, qFC-11 is a newly detected stable QTL that will provide new opportunities for improving rice fat content through marker-assisted selection.