Genus Oryza: All kinds of rice

GENUS ORYZA: All kinds of rice

a- Oryza genus in the modern scientific classification

Kingdom:	Plantae
Phylum:	Angiosperms
Class:	Monocots
Order:	Poales
Family:	Poaceae = Gramineae =Poa L. (12 subfamilies with 91 genera)
Subfamily:	Bambusoideae ( with 13 tribes)
Tribe	Oryzeae (12 tribes with over 20 genera)
Genus	Oryza L. (There are 13 species )

In the modern scientific classification the Family Poaceae has about 800 genera with over 10,000 species. Family Poaceae has 12 subfamilies in which subfamily Bambusoideae is one of them with 91 genera.

Subfamily Bambusoideae has 13 tribes and divided into two groups: the Oryzodae (12 tribes) and the Bambusodae (1 tribe).

The Oryzodae has 12 tribes, as following:

1&2-Oryzodae: This group is also separated into subfamily Oryzaceae (13 genera).

3&-4-Tribe Anomochloeae: This tribe is also separated to form subfamily  Anomochlooideae. (1 genera).

5-Tribe Diarrheneae (1 genera).

6-Tribe Ehrharteae (1 genera).

7-Tribe Olyreae (20 genera).

8-Tribe Phaenospermatae (1 genera).

9-Tribe Phareae (4 genera).

10-Tribe Phyllorhachideae (2 genera).

11-Tribe Streptochaeteae (1 genera).

12-Tribe Streptogyneae (1 genera).

A kind of wild rice

-The Tribe Oryzeae: This tribe also forms subfamily Oryzoideae (13 genera).

Chikusichloa, Hydrochloa, Hygroryza, Leersia, Luziola, Maltebrunia, Oryza, Porteresia, Potamophila, Prosphytochloa, Rhynchoryza, Zizania,Zizaniopsis.

-The Genus Oryza is a genus of seven to twenty species (depending on many different systems) of rices or grasses in the tribe Oryzeae, within the subfamily Bambusoideae, native to tropical and subtropical regions of Asia, Northern Australia and Africa. They are tall, wetland grasses, growing to 1–2 m tall; the genus includes both annual  and  perennial species.

Harvesting wild rice

Oryza is situated within the tribe Oryzeae, which is characterized morphologically by its single-flowered spikelets whose glumes are almost completely suppressed. In Oryza, two sterile lemma simulate glumes. The tribe Oryzeae is within the subfamily Bambusoideae, a group of Poaceae tribes with certain features of internal leaf anatomy in common. The most distinctive leaf characteristics of this subfamily are the arm cells and fusoid cells found in their leaves. The Bambusoideae are in the family Poaceae, as they all have fibrous root systems, cylindrical stems, sheathing leaves with parallel-veined blades, and inflorescences with spikelets.

While USDA plants lists have only seven species, others have identified up to 17 or over, including sativa, barthii, glaberrima, meridionalis, nivara, rufipogon, punctata, latifolia, alta, grandiglumis, eichingeri, officinalis, rhisomatis, minuta, australiensis, granulata, meyeriana, and brachyantha.

One species, Asian rice (O. sativa), provides 20% of global grain and is a food crop of major global importance. The many species mentioned above are divided into two subgroups within the genus (wild and planting rice).

Colors of some wild rice grains

b-Selected species

-Oryza australiensis- wild rice grows in northern Australia.

-Oryza barthii-wild rice grows in sub-Saharan Africa.

-Oryza glaberrima - African growing rice.

-Oryza latifolia- wild rice in central and south America.

-Oryza longistaminata-Red wild rice in South Africa

-Oryza meridionalis-wild rice in  Western Australia, Northern Queensland.

-Oryza officinalis- wild rice in  Sri Lanka.

-Oryza punctata-wild rice in central and north Africa.

-Oryza rufipogon – wild rice in north America named brownbeard or red rice.

-Oryza sativa - Asian growing rice.

-Oryza nivara - Indian wild rice.

c-Introduction to growing rice

Rice is central to the lives of billions of people around the world. Possibly the oldest domesticated grain (~10,000 years), rice is the staple food for 3.5 billion people and growing rice is the largest single use of land for producing food, covering 9% of the earth's arable land. Rice provides 21% of global human per capita energy and 15% of per capital protein . Calories from rice are particularly important in Asia, especially among the poor, where it accounts for 50-80% of daily caloric intake. As expected, Asia accounts for over 90% of the world's production of rice, with China, India and Indonesia producing the most . Only 6-7% of the world's rice crop is traded in the world market. Thailand, Vietnam, China and the United States are the world's largest exporters. The United States produces 1.5% of the world's rice crop with Arkansas, California and Louisiana producing 80% of the U.S. rice crop.

85% of the rice that is produced in the world is used for direct human consumption . Rice can also be found in cereals, snack foods, brewed beverages, flour, oil, syrup and religious ceremonies to name a few other uses.

Rice belongs to the genus Oryza and has two cultivated and 22 wild species. The cultivated species are Oryza sativa and Oryza glaberrima. Oryza sativa is grown all over the world while Oryza glaberrima has been cultivated in West Africa for the last ~3500 years . Rice is grown under many different conditions and production systems, but submerged in water is the most common method used worldwide. Rice is the only cereal crop that can grow for long periods of time in standing water. 57% of rice is grown on irrigated land, 25% on rainfed lowland, 10% on the uplands, 6% in deepwater, and 2% in tidal wetlands . The flooded rice paddy is a field of aquatic biodiversity, providing a home for fish, plants, amphibians, reptiles, mollusks, and crustaceans, which many of can be used as a means to incorporate protein into the diets of poor and malnourished people in low and middle income countries that farm rice .

Just as rice can be grown in many different environments, it has many characteristics, making one variety more popular in one region of the world than another. Rice can be a short, medium or long grain size. It can also be waxy (sticky) or non-waxy. Some rice varieties are considered aromatic. Rice also comes in many different colors including brown, red, purple and black .

With that brief introduction to rice, we encourage you to explore Gramene's Doorway to Oryza to learn many more specific details about this versatile and very important grass species.

References:

1-Oryza sativa- From Wikipedia, the free encyclopedia

2-Gramene Statistics and Queries for Oryza.

3. IRRI, 2001. Rice Research and Production in the 21st Century.

4. Chaudhary, R., et al., eds., 2001. Speciality rices of the world. Science Publishers, Inc, NH, USA.
5-International Year of Rice, 2004. "Rice and human nutrition" [PDF] factsheet. 

6-Rice Knowledge Bank www.knowledgebank.irri.org/.