The morphological characteristics of root systems in rice cultivars were examined employing different nutrition levels. Norin 3 had a small spreading angle, on the other hand, Rikuu 132 showed a large spread. F1 plants from the cross between Norin 3 and Rikuu 132 had an intermediate spreading angle of root system between that of each parent. In the rhizotron experiments we have observed that F 2 segregating rice populations the rooting patterns are controlled by a single dominant gene. We are continuously selecting germplasm that has deeper rooting habit.
Deeper rooting helps the plant withstand lodging and leads to higher yields.
Moreover, Monolith method was used to investigate the root morphology under the field condition. In this experiment, significant differences on the root system were recognized. No-tillage and traditional transplanting treatment were used with Koshihikari and Bluebonnet. The same results was shown in this experiment. To get the stable yield of rice under the different cultivation technique, it is necessary to promote the root growth from surface to deeper layer in the soil.