The genes of the Green Revolution.

The spectacular increases in wheat and rice yields during the 'Green Revolution', were enabled by the introduction of dwarfing traits into the plants. Now, identification of the genes responsible for these traits shows that they interfere with the action or production of the gibberellin (GA) plant hormones. We knew that the wheat Rht genes encode growth repressors that are normally suppressed by GA, and recent work shows that the rice sd1 gene encodes a defective enzyme in the GA-biosynthetic pathway.