Sampling locations of Oryza rufipogon (blue) and O. nivara (red) populations used in this study. Inset photo of perennial O. rufipogon (left) and annual O. nivara (right) plants originally published in Journal of Systematics and Evolution (2013, 51: Cover) and adapted with permission. Circles denote the six population pairs of O. rufipogon and O. nivara used in the common garden experiment, of which three pairs (i.e., NEP1, LAO2, and KHM) were used for artificial crossing. The green star and cross show the locations where the common garden experiment and the artificial crossing study were conducted, respectively. Detailed information on all the populations is listed in supplementary table S1, Supplementary Material online.