Japonica rice explained

Japonica rice (Oryza sativa subsp. japonica), sometimes called sinica rice, is one of the two major domestic types of Asian rice varieties. Japonica rice is extensively cultivated and consumed in East Asia, whereas in most other regions indica rice is the dominant type of rice. Japonica rice originated from Central China, where it was first domesticated along the Yangtze River basin approximately 9,500 to 6,000 years ago.[1] [2] [3]

Classification

The subspecies japonica can be classified into three subgroups, 'temperate japonica', 'tropical japonica' (obsolete designations: 'javanica';),[4] and 'aromatic'.[5] Temperate japonica is cultivated in East Asia (China, Japan, Korea, Vietnam, and Taiwan), while tropical japonica is in Indonesia, Madagascar, and also the Americas where it was brought to with slave trade.[6]

Characteristics

Japonica rice grains are rounder, thicker, and harder, compared to longer, thinner, and fluffier indica rice grains. Japonica rice is also stickier due to the higher content of amylopectin, whereas indica rice starch consists of less amylopectin and more amylose.[7] Japonica rice plants are shorter than indica rice plants.

Genetics

Temperate japonica has a large amount of waxy protein and a low amount of the non-waxy type. Non-waxy rice proteins are produced by four alleles, each producing one of four protein subtypes. Temperate japonica is the only source of Type III, shares Type IV with only tropical japonica ("javanica"), and lacks Type I and Type II.[8]

Cultivars

See also

Notes and References

  1. Web site: Hirst. K. Kris. The Origins and History of Rice in China, India/Pakistan and Africa. 2020-08-02. .
  2. Web site: 2011-05-02 . Rice's origins point to China, genome researchers conclude . James. Devitt. 2020-08-02 . . en-US.
  3. Gross. Briana L.. Zhao. Zhijun. 2014-04-29. Archaeological and genetic insights into the origins of domesticated rice. . en. 111. 17. 6190–6197. 10.1073/pnas.1308942110. 0027-8424. 24753573. 4035933. 2014PNAS..111.6190G. free.
  4. Web site: javanica rice. . 27 December 2016.
  5. Garris . Amanda J. . Tai . T. H. . Coburn . J. . Kresovich . S. . McCouch . S. . Susan McCouch . 2004 . Genetic structure and diversity in Oryza sativa L. . . 15654106 . 10.1534/genetics.104.035642 . 169 . 3 . 1631–1638 . 1449546.
  6. 松尾 弌之. (2009).“「アメリカ50州」の秘密 “ レッカ社
  7. Web site: Endless Variations on Rice. Kim. Jin-young. 4 November 2016. . Korea Foundation. 27 December 2016.
  8. Book: 1991 . 2 . Manila, Philippines . . Rice Genetics : Proceedings of the Second International Rice Genetics Symposium 14-18 May 1990 . Rice Genetics Collection .