Fig. 4

The hybrid origin of O. sativa. a Gene genealogies showing two recombinant alleles identified in O. sativa. One is japonica allele at OsAPS1, and the other indica allele at iPGAM1. Both can be generated by one crossing-over event during synapsis between chromatids of parental genomes O. rufipogon (Or) and O. nivara (On), as shown to the right. b Origins of structural genes of two metabolic pathways in rice. c The distribution of plant height in O. sativa. Plant height was measured at harvest on F2 progeny (N = 305) of a cross between Heidao as pollen receiver and Jixuenuo as pollen donor. See Additional file 6: Data 1 for detail. d Variation of the anther length just before dispersal of pollen. A total of 65 plants from the F2 population, one japonica, and three indica cultivars were sampled in two days at noon when flowers (N = 466) were open. See Additional file 7: Data 2 for detail. e Degree of panicle exsertion in O. sativa. A random sample of 232 plants from 46 accessions of indica, japonica, and their crossed progeny were measured at 696 panicles for stem length beyond the sheath of flag leaf. Details see Additional file 7: Data 2. f A brief summary of rice domestication. The green rectangle indicates the period when rice was selected as one crop. The colored arrows show contributions of parental genomes, and the bar of the same color indicates slight more contribution of the species to the subgroup. The dots represent other subgroups