Although Thailand is quite small, 513115 sq. km. (approximately the same size as France), different ecologies and geography in distinct parts of the country could
have some effects on our rice diversity. The first three of the four rice ecologies: irrigated, deep water, upland, and rainfed lowland ecosystems, showed distinct groups for both cluster and structure analyses. The irrigated rice lines, planted in irrigated areas in the Central plain, were grouped together and showed similar genetic structure
to IRRI germplasm. Most of the tested upland rice lines were planted in hilly areas in the North, and they were grouped with Japonica rice. Deep water rice lines were
planted in specific areas having high levels of water in the Central plain, and they were clustered together in a distinct group. Interestingly, three out of the four rainfed lowland rice lines from the South showed genetic structure that is similar to the deep water rice. In addition, groups that were sorted by population structure also displayed significant genetic difference among them.