Dual-low breeding and application of two-line rice ‘Peiai 64S’ after space flight

Objective  To solve the problems of thermo-photo-sensitive genic male sterile (PTGMS) rice ‘Peiai 64S’ caused by rising critical sterility-inducing temperature (CSIT) and higher amylose content in practical production, and breed new male sterile line.

Method  ‘Peiai 64S’ seeds, which were carried by the agricultural satellite named as “practical #8”, were planted, tracked and directionally selected. The steady sterile line with low amylose content was obtained. In the mean time, according to YUAN Longping’s method for the purification and propagation of PTGMS lines, CSIT was selected and identified by adding pressure.

Result  The mutant plants with low amylose content (about 8.69%) and low CSIT (below 23.0 ℃) were found. One new mutant line with the dual-low characteristics was identified and named as ‘Hang 17S’. The plant height of ‘Hang 17S’ was 79.62 cm, the flag leaf length and width were 32.54 and 1.82 cm respectively, the panicle number per plant was 11.4, the panicle length was 22.01 cm and the grain number per panicle was about 181. Except for the flag leaf width, there was no significant difference for most of the traits compared with its wild type ‘Peiai 64S’.

Conclusion  The newly bred ‘Hang 17S’ is much like its wild type ‘Peiai 64S’ for most of the traits except for the dual-low characteristics. And it retains the characteristics of good outcrossing rate and strong combining ability of ‘Peiai 64S’. ‘Hang 17S’ was appraised by the government committee and commercially released in 2015.