A comparative study on the low temperature tolerability of different photo-thermo sensitive genic male sterile lines in rice

【Objective】To study the low temperature tolerability of different photo-thermo sensitive genic male sterile( PTGMS) lines in rice so as to provide a basis for breeding and utilizing of the PTGMS lines with stable male sterility. 【Method 】At the temperature sensitive stages,the PTGMS lines of Xian S,N28 S,Annong S,Peiai64 S,N9S and N2 S were treated at 21 and 23 ℃ for 3,7 and 10 d in the plant growth chambers,respectively. The pollen fertilities of these PTGMS lines were investigated for 30 d after they were transferred to the outside of plant growth chamber to analyze their low temperature tolerability.【Result】The low temperature tolerability order of these PTGMS lines was Xian S,N28 S Annong S Peiai64S N9 S,N2S. The non-pollen type PTGMS lines of Xian S,N28 S and Annong S produced no fertile pollens after treated at 21 and 23 ℃ for 3 d. Xian S and N28 S were still completely sterile,while Annong S produced some fertile pollens after treated at 21 and 23 ℃ for 7 d. After treated at 21 and 23 ℃ for10 d,Xian S and N28 S produced some fertile pollens,and Annong S produced more fertile pollens compared with that for 7 d. However,the typical abortion type PTGMS lines of Peiai64 S,N9S and N2 S produced some fertile pollens after treated at 21 and 23 ℃ for 3,7 and 10 d respectively,except forPeiai64 S after treated at 23 ℃ for 3 d. The percentage of fertile pollen increased with the continuous extension of time and the temperature dropping. 【Conclusion】The low temperature tolerability of the PTGMS line relates to the type of pollen abortion besides the critical temperature inducing sterility( CTIS),and the non-pollen type PTGMS line with low CTIS shows stable male sterility. It should be paid more attentions to the non-pollen type PTGMS lines with low CTIS in the breeding process of the practical PTGMS lines.