The Rice Plant
The rice plant, Oryza sativa, comes from the same taxonomical family as the grasses.
Genome of Rice
The 430Mb genome of rice is distributed among 12 chromosomes.
Subspecies of Rice
The sticky, short-grained japonica variant and the non-sticky, long-grained indica type are the two primary subspecies of Oryza sativa. The Javanica minor subspecies has broad grained and thrives in tropical environments.
Variety and Colors of Rice
Rice comes in a variety of hues, including white, black (or glutinous), purple, and red (Shao, Y., & Bao, 2015).
Growth Phases of Rice
Depending on the variety and environmental factors, rice takes three to six months to develop into a plant. Furthermore, rice growth falls under 3 phases, that is vegetative, reproductive, and the ripening stage.
Germination Stage
The germination stage involves the emergence of the first shoot and the roots from the seed, thus the growth of the rice plant. Moreover, germination of the rice seed entails absorption of water from the soil and temperature exposure of about 10-40°C, thus breaking the seed dormancy stage. Afterward, seedlings are planted in a flooded soil, where the shoot emerges. The roots develop after the emergence of the first shoot, which appears in the air. On the other hand, if transplantation occurs in the soil that is non-flooded, the root protrudes out first from the seed, then follows the shoot.
Vegetative Phase
The vegetative phase development varies from one variety of rice to the other, but is commonly approximated to be between 55 to 85 days. This stage involves the growth of leaves, tillers, and the increase in the height of the plant. The onset of the vegetative phase begins immediately when the seeds germinate into a seedling and ends during the tillering period. The seedling stage commences after the emergence of the first shoot and the root. Seminal roots and the first four to five leaves emerge at this phase, after which development of the plant continues for 3-4 days. Moreover, the plant continues to grow with the emergence of one leaf after every 3-4 days during the early vegetative stage. Tillering period initializes the late vegetative stage that commences from the time of appearance in the first tiller to the period which maximum tillering is achieved, i.e., 40 days after the sowing. The stem of the rice begins to lengthen during the end of the tillering phase while the height stops developing immediately before initiation of the panicle i.e. 52 days after sowing, thus marking the end of the vegetative stage.
Reproductive Phase
Some of the notable signs for commencement in reproductive phase is bulging of the leaf stem. Leaf stem swelling helps to cover the panicle which is developing, i.e., 'booting' stage (Fujino et al., 2014); nevertheless, the panicle tip protrudes from the stem and keeps on to grow to the 'heading' stage where it is fully visible. The flowering process develops a day after 'heading' stage and continues for the next seven days. During this process, flowers open and enhance the pollination process.
Ripening Stage
The ripening stage commences at the flowering period and ends when it is ready to be harvested. This phase takes close to thirty days depending on the rain as well as temperature changes. High rainfall and low temperatures increase the ripening stage, while the vice versa shortens the period. Some of the ripen stages include milky, yellow, dough, ripe, and maturity stage.
In Conclusion
In conclusion, the cultivation of Oryza sativa involves a procedural development phase which is intensive in regards to workforce, time, and requires proper observation.
References
Shinada, H., Iwata, N., Sato, T., & Fujino, K. (2014). QTL pyramiding for improving of
cold tolerance at fertilization stage in rice. Breeding science, 63(5), 483-488.
Shao, Y., & Bao, J. (2015). Polyphenols in whole rice grain: Genetic diversity and
health benefits. Food chemistry, 180, 86-97.
