Genetic interaction network of quantitative trait genes for heading date in rice

Several quantitative trait genes (QTGs) related to rice heading date, a key factor for crop development and yield, have been identified, along with complex interactions among genes. However, a comprehensive genetic interaction network for these QTGs has not yet been established. In this study, we use 18K-rice lines to identify QTGs and their epistatic interactions affecting rice heading date. We identify 264 pairs of interacting QTL and construct a comprehensive genetic network of these QTL. On average, the epistatic effects of QTL pairs are estimated to be approximately 12.5% of additive effects of identified QTL. Importantly, epistasis vary among different alleles of several heading date genes. Additionally, 57 pairs of interacting QTGs are also significant in their epistatic effects on 12 other agronomic traits. The identified QTL genetic interactions are further validated using near-isogenic lines, yeast two-hybrid, and split-luciferase complementation assays. Overall, this study provides a genetic network of rice heading date genes, which plays a crucial role in regulating rice heading date and influencing multiple related agronomic traits. This network serves as a foundation for understanding the genetic mechanisms of rice quantitative traits and for advancing molecular breeding efforts.