Abstract: 【Objective】To ascertain the root properties of hybrid rice and mechanism of increasing yield under different tillage system. 【Method】 The effects of no-tillage (NT) and conventional tillage (CT)on root properties and yield of direct broadcasted (DB) hybrid rice and raise seedlings and transplanted (RT) hybrid rice on the conditions of field experiments were studied. 【Results】 The results showed that the root/shoot ratio, root dry weight, root absorbing surface area and root active absorbing surface in NT at maximum tillering stage were higher than those in CT. Furthermore, the root weight and root weight density in 0-5 cm soil layer and the specific root length in 5-10 cm and 10-20 cm soil layer of NT at mature stage were higher than those of CT no matter which rice establish method was adopted. The root length and root length density and root surface area in 0-5 cm soil layer of NT at mature stage were higher than those of CT, and also the total 32P activity absorbed by rice roots and oxidation ability of rice roots of NT rice at maximum stage were 40.72% and 13.81% higher than those of CT on the average in RT, respectively. In DB condition, the total 32P activity absorbed by roots and the root oxidation ability in NT at maximum stage, booting stage and full heading stage were 54.56% and 12.59%, 19.53% and 24.06%, 2.80% and 74.19% higher than those of CT on the average, respectively. In addition, the partitioning of 32P absorbed by root into aerial parts in NT rice at booting stage was 13.78% higher than that of CT on the average, while the root residual rate of 32P in NT at the same stage was 6.84% lower than that in CT rice on the average. The effective panicle in NT was lower than that in CT, while the spikelet number per panicle in NT was higher than that in CT no matter which rice establish method was adopted. The rice yield of NT rice reached to 8979.0 kg·ha-1and 8588.0 kg·ha-1, increasing by 2.30%, 1.19%, compared with CT on the average on DB and RT condition, respectively, although the difference was not significant between CT and RT. 【Conclusion】 The rice yield superiority in NT was obvious compared with in CT, which was the reaction of good root properties in NT.

Key words: Tillage system, Hybrid rice, Root properties, Yield