Study on growth and development of rice root under different water regimes was conducted in greenhouse at Thai Nguyen Agriculture and Forestry University in 2014. The Khang Dan 18 variety with 5 treatments of water regimes: (1) keeping water all the season
(2)
(3), and (4) are. treatments of alternatively drained and supplied water regularly 5, 10 and 15 days all the season respectively
and (5) moisturizing soil maintained at least 80 percent humidity all the season). The results shown the rice rhizophere was affected by water: such as number of root, diameter of root, weight of root and the length of root. The rice root growth almost concentrated from 015cm of deep soil layer, a few does from 15-25cm of deep. The treatments with low water level resulted more number of roots at 15 - 25 cm layer. The rate of root weight on shoot weight increased significantly at panicle initiation time to flowering time and decreased notably from flowering time to the milky compression.