Abstract:

Wide compatibility restorer line is an important parent material for utilizing the heterosis of inter- subspecies, i.e. indica and japonica rice. In production of hybrid rice, indica CMS lines mostly utilize the male sterile cytoplasm from Hainan male sterile wild rice (WA type) and partly from Hainan red awned wild rice (HL type), japonica CMS lines mostly utilize the male sterile cytoplasm from India Chinsurah Boro Ⅱ (BT type). These are so called 3 kinds of representative cytoplasm types. The different CMS lines need different restoring genes to restore their fertilities. So, it is very difficult for a line with single restoring gene to restore different CMS lines. Intention of this study was to breed a restorer line with wide compatibility and wide restoring ability and find a way to utilize the heterosis between indica and japonica rice in the three-line breeding program. In order to screen the restorer lines with wide restoring ability to different CMS lines, one set of isonuclear alloplasmic CMS lines with wide compatibility of Suqiu genetic background and above 3 kinds of cytoplasms were crossed with 9 indica restorer lines (include 136, 388, 6078, Minghui 63, 413, 559, 9311, Teqing, and 1001) and 10 japonica restorer lines(include T1950, C9083, 77302-1, Ninghui 3-2, C Bao, Wanhui 9, Xianghu 115, C9022, Pei C 311, and Lunhui 422). According to the appraisal result of spikelet fertility of F₁ between proposed restorer lines and CMS lines, restorer line 6078 had wide restoring ability to the above 3 kinds CMS lines. Afterward, wide compatibility gene S5n of Lemont was transferred into 6078, and SWR 78 (SWR is the abbreviation for Jiangsu wide compatibility restorer line) with wide compatibility and wide restoring ability was bred by successive back-crosses. By test-crossing and appraising, SWR 78 had wide restoring ability to 10 indica and japonica CMS lines with 4 different kinds of cytoplasm.

Key words: Rice, Wide compatibility, Cytoplasmic-nucleic male sterility, Restorer line