The tiller number is associated with grain yield. Old tillers contribute to yield as much as main shoots do, but late tillers waste investment in primary production, although some of them remobilize reserve carbon. Late tillers synchronize with early tillers at maturity, resulting in less biomass and yield, and are sometimes unproductive altogether. The competence for accruing yield benefits declines progressively with age. It happens so because the initiation of tillers is staggered and spaced in chronological order, and the later-formed tillers on upper internodes have little time for primary production supportive of grain yield. The hierarchy of tiller development becomes evident as grain yield becomes poorer for each successive tiller. High tillering was a breeding priority for semi-dwarf rice over traditional rice. But, augmenting the tiller number, as has been done in profuse-tillering semi-dwarf rice, by adopting an ideotype approach was not a preferential choice for advancement of yield potential. Therefore, the pyramiding of potentially useful traits in super or NPT rice invoked the preclusion of unproductive tillers amounting to low tiller numbers per plant.