Plant architecture, referring here to the aerial part of a higher plant, is mainly determined by factors affecting shoot branching, plant height and inflorescence morphology. Significant progress has been made in isolating and characterizing genes that are directly involved in the formation of plant architecture, especially those controlling the initiation and outgrowth of axillary buds, elongation of stems and architecture of inflorescences. Most of these genes are conserved between dicotyledonous and monocotyledonous plants, indicating that these plants share similar regulatory pathways to establish their shape. The conservation of these genes makes them of great agronomical importance for improving crop yields.