commercial cultivars grown in different ecologies in the
country. Thus, there is a lack of information on genetic
structure of Thai rice. Thailand is the world’s largest exporter
of rice, and is famous for high-quality, long-grain
white rice, because the breeding of Thai rice has been
focused on maintaining good grain characteristics and
quality. Thailand has a large collection of diverse rice
germplasm, including the famous Thai jasmine rice
(Chitrakon and Somrith 2003).
In Thailand, rice ecologies can be classified as irrigated,
rainfed lowland, deep water, and upland ecosystems.
Rainfed lowland is the majority of rice growing