Flowering time is an important ecological trait that determines growing seasons and regional adaptability of plants to specific natural environments.Rice is a short-day plant that originated in the tropics.Increasing evidence suggests that the northward expansion of cultivated rice was accompanied by human selection of the heading date under non-inductive long-day conditions (LDs).We report here the molecular cloning and characterization of DTH2, a minor-effect QTL that promotes heading under LDs.