Evaluation of Heat Tolerance and Breeding Application of Rice Restorer Line R1056

The combination of interval sowing and green house with auxiliary heating was used to identify the heat tolerance of rice restorer line R1056 and the hybrid combinations from R1056 at flowering stage. The agronomic traits of R1056 and its hybrid combinations were also evaluated. The results showed that under high temperature treatment of 38 ℃ at flowering stage, the seed setting percentage, the anther dehiscence rate and the number of pollens on stigma of R1056 were 70.4%, 75.5% and 78,equivalent to the heat-tolerant variety N22(CK) and were significantly higher than those of heat-sensitive varieties. The hybrid combinations from R1056 were between R1056 and the heat-sensitive varieties. R1056 had excellent agronomic traits with high combining ability. The hybrid combinations from R1056 were characterized by shorter plant height, more spikes and higher yield. The results indicated that R1056 was both an outstanding heat-tolerant germplasm and an excellent restorer line of three-line hybrid rice.