The rice plant has several distinct successive nodes on the culm. A node bears one leaf. On the axil of the leaf, there is a bud that forms a stem branch or tiller. Tiller development is characterized by three stages: (A) apical and axillary meristem initiation, (B) bud development, and (C) extension of bud growth to a tiller. The tillers generated on the leaf axils of the main culm are primary. In the same sequence, secondary and tertiary tillers are produced on primary and secondary tillers, respectively. Tiller production continues in the leaf axils until the end of the vegetative period. Tiller genesis occurs temporally in the main and other shoots of the plant, but maturity is almost synchronous. The tiller number varies with the variation in genotype and growth habitat. Fertilizing rice with NPK during the vegetative growth period promotes tillering, leading to high grain yield. However, heterogeneity in tiller yield associated with tiller formation and fertilizer application reveals that tiller asynchrony increases with the level of fertilization, mainly nitrogen. The positive effects of nitrogen on the rice population are the outcome of an increase in the grain yield of early-formed tillers. Thus, the primary tiller number is always critical for achieving high grain yield in rice.