Grain yield is heavily influenced by the architecture of the inflorescence. However, little is as yet known concerning the genetic control of this trait complex in crops. The identification of the DEP1 locus offers prospects for gaining a deeper understanding of the molecular basis of panicle branching in rice. As a key regulator of grain number, the DEP1 locus (and perhaps also its homologs in other small-grain cereals) may provide a means of manipulating grain yield in these crucial crops.