The growth of rice plant can be divided into three stages: vegetative, reproductive, and ripening. The full cycle of growth varies from 70 to 170 days depending on the cultivar. The duration of the vegetative and reproductive phases is identical, but the duration of the vegetative phase differs between cultivars. The vegetative phase extends from germination to panicle initiation, during which the plant increases in size by the increase in root formation, leaf number, and tiller number. The reproductive phase covers plant growth from panicle initiation to anthesis. It is characterized by the elongation of the main culm, degeneration of unproductive tillers, the emergence of flag leaves, booting, heading, and the emergence of anthers. In the ripening phase, assimilates are stored in developing grains as reserve food; over time, the grains lose water and harden physically to reach maturation. An assortment of MADS-box genes controls the development of roots, leaves, and floral structures. The MADS-box homeotic genes defining the floral organ identity of rice spikelets are divided into five classes encapsulated in a scientific model adopted for angiosperms called the ABCDE flower model. The identity of the genes depends on which organ they affect. The patterns of MADS-box gene expression in the meristem that is responsible for floral organ identity are regulated by upstream promoter regions and transcription factors. A rice panicle is a complex determinate type of racemose branching inflorescence borne on the uppermost internode of the culm named the peduncle. The main axis bears 8–10 primary branches and 2–3 secondary branches on each primary branch. Pedicellate spikelets are borne on the top and nodes of branches and bear a grain each upon maturity. The rice spikelet is hermaphrodite. The pollens released from the anthers travel in the air within the hull for self-fertilization. Like in other angiosperms, double fertilization in rice results in the development of endosperm and embryo, and interactions between them affect seed setting and development. The role of the PTB1 (POLLEN TUBE BLOCKED 1) gene is crucial for the regulation of panicle set and yield.