Japonica rice GC13 was considered as a special wide compatibility variety (SWCV), because its compatibility was weak within subspecies and strong between subspecies. The result of genetic analysis of wide compatibility and allelism indicated that GC13 expressed an obvious effect of a major gene controlling wide compatibility, which may be modified by minor genes and be allelic to one of the locus S 7, S 9 or S 15 . GC13 could be combined inter-subspecifically with PGMS line Pei-ai 64S. GC13 is one of restorer gene donors of Japonica group, from which the restorer lines GR209, GR220 and GR238 were developed.