Tolerance of a Restorer Line R1056 to High Temperature and Its Application in Rice Breeding.

The tolerance of a restorer line R1056 of rice and its hybrid combinations to high temperature at flowering stage was evaluated by sowing them at three different dates and transplanting them into a greenhouse equipped with heating system at flowering stage. Several important agronomic traits of these rice varieties or combinations were also measured. The results revealed that treated by high temperature (38 °C) at flowering stage, the seed setting rate (70.4%), percentage of dehiscent anthers (75.5%), and pollen number per floret (78) of R1056 were close to those of N22, which is tolerant to high temperature, and significantly higher than those of the rice varieties sensitive to high temperature. The seed setting rate, percentage of dehiscent anthers, and pollen number per floret of the hybrid combinations generated from R1056 were smaller than those of R1056, but higher than those of the rice varieties sensitive to high temperature. R1056 had excellent agronomic traits, and good combining ability, and its hybrid combinations had low plant height, numerous panicles and high yield, suggesting that R1056 is not only an excellent rice variety with tolerance to high temperature, but also an excellent restorer in three-line hybrid rice breeding. [ABSTRACT FROM AUTHOR]