Fig. 5
Genetic model of the heterosis for sorghum culm length (CL). Six genes (Dw1, Dw3, Dw7a, SbPhyB, SbGhd7, and SbPRR37) contributed to the heterosis for the CL of F1 variety ‘Tentaka’. The dark and thin color of six genes indicate dominant and recessive alleles, respectively. The thick lines in the circles represent the linkage between genes, resulting in pseudo-overdominance in F1 due to the repulsive linkages. The inner lines represent epistasis, and the dotted lines show repressed relationships. The female parent (MS79) carries dw7a and sbghd7, and the male parent carries dw1, dw3, sbphyB, and sbprr37. The F1 hybrid has all dominant alleles of six genes and positive epistasis, but the effects of epistatic interactions are weaker than those of single QTLs. Therefore, the heterosis is explained mainly by the dominance model but partially by the epistasis model.
