There are three groups of glutinous rice-based on grain sizes, small (japonica), medium (upland), and long slender (indica) grains. The origin of glutinous rice has become a hot topic for discussion by evolutionists who speculate that glutinous rice has two roots. Glutinous rice has been grown in the Greater Mekong Sub-region (GMS), especially in Laos, for 4,000 – 6,000 years, and at least 2,000 years in Yunnan, China, by Tai ethnic groups. In particular, ethnic groups in Myanmar, Thailand, and Laos helped conserve upland rice diversity. Furthermore, Laos has contributed the most remarkable genetic diversity in glutinous rice to the International Rice Genebank at the International Rice Research Institute (IRRI).
Laos and Thailand are the only countries that consume glutinous rice as primary stable food. Laos consumes glutinous rice at 171 kg per year, the highest per capita consumption globally. In Thailand, glutinous rice is vital for household consumption in the north and northeast at 125-155 kg per capita per year. Thai farmers typically grow side-by-side, glutinous rice for household consumption and Hommali rice for cash. The current consumption of glutinous rice in Thailand has been on the rise recently due to the popularity of the northeastern cuisines in restaurants and street foods among Thais and tourists. From 2021 to 2026, the demand for glutinous rice is increasing healthily.