Natural variation among O. rufipogon and O. sativa in the degree of seed shattering. The degrees of seed shattering were measured upon maturation of the rice seeds. Colors of bars indicates subgroups of lines: black for O. rufipogon, orange for indica, green for tropical japonica, dark blue for temperate japonica with the qSH1-Kas allele, and light blue for temperate japonica with the qSH1-Nip allele. A clear association of the degree of seed shattering with the presence of a qSH1 genotype can be seen, but qSH1 alone cannot explain all the variation in the degree of seed shattering in tropical japonica. Note that all O. sativa contain the defective sh4 allele. Data were obtained from Konishi et al. .