Rice can be categorised into two main types – Japonica and Indica.
The characteristics and forms of these two types of rice differ.
Japonica rice is usually grown in temperate climates. The grains are round and do not easily crack or break. When cooked, this rice is sticky and moist. The rice produced in Japan is mostly Japonica.
Indica rice is usually grown in hot climates. The grains are long and tend to break easily. When cooked, the rice is fluffy and does not stick together. Most of the rice produced in Southern Asia, including Sri Lanka, India, Thailand, Vietnam and Southern China is Indica rice.
Both Japonica and Indica types of rice include non-glutinous and glutinous rice. Each type of rice has its own special characteristics and each has its own place in rice cooking.
Non-glutinous rice is popularly used in general rice cooking. This rice is somewhat transparent and when cooked is less sticky than glutinous rice. It is usually cooked in water and served plain.
Glutinous rice tends to be white and opaque and is very sticky when cooked. It is commonly used to make rice cakes and various kinds of desserts, and processed to make rice snacks.
Indica is grown mostly in tropical and subtropical regions and accounts for more than 75 percent of global trade. Indica rice cooks dry, with separate grains.
Japonica rice, typically grown in regions with cooler climates, accounts for more than 10 percent of global rice trade.
Aromatic rice, primarily jasmine from Thailand and basmati from India and Pakistan, accounts for 12-13 percent of global trade and sells at a premium in world markets.
Glutinous rice, grown mostly in Southeast Asia and used in desserts and ceremonial dishes, accounts for the remainder.
Aromatic and Glutinous rice varieties are seen in both Indica and Japonica main types of rice.
There are more than 40,000 varieties of cultivated rice (grass species Oryza sativa) said to exist. But the exact figure is uncertain. Over 90,000 samples of cultivated rice and wild species are stored at the International Rice Genebank and these are used by researchers from the world.
The different varieties of rice are not considered interchangeable, either in food preparation or agriculture. Therefore, each major variety is a completely separate market. It is common for one variety of rice to rise in price while another one drops in price.