Ideal crop plant architecture is mediated by tassels replace upper ears1, a BTB/POZ ankyrin repeat gene directly targeted by TEOSINTE BRANCHED1

Significance Teosinte, the wild ancestor of maize, is a highly branched and low-yielding plant. Branch suppression in maize was achieved through selection for overexpression of the teosinte branched1 ( tb1 ) transcription factor that acts as a repressor of axillary branching. Here, we show a molecular mechanism for how TB1 transformed teosinte into a viable crop plant. The tassels replace upper ears1 ( tru1 ) mutant causes maize to revert back to its highly branched ancestral state, much like tb1 . We demonstrate that tru1 is a direct target of TB1 and is overexpressed in modern maize. The genetic mechanism underlying the tb1 and tru1 pathway reveals a blueprint for domesticating new grass species.