Abstract
Rye breeding using F$_1$ hybrid began about 30 years ago, when cytoplasmically inherited forms of male sterility (CMS) and corresponding nuclear restorers were detected. It is very important to produce inbred lines for making hybrid lines because of strong self-incompatibility in rye. Among the 456 rye germplasms used in hybrid breeding scheme, 24 lines (5.3%) had the above 60% of self-fertility, and six lines of them were selected for their good agronomic characteristics and were used for subsequent inbreeding program. The average self-fertility of selected six lines was 78.4%, ranging from 72.2 to 99.5%. Genetic analysis for the self-fertility using $F_2$ populations showed that the segregation of self-fertile and sterile plants in F$_2$populations could be fit into 3 to 1 ratio suggesting self-fertility in rye be controlled by one major gene. The four different self-fertile lines, PI237923, 5C11, 5G5 and Florida black, had the same self-fertility gene because their F$_2$ plants showed almost the same self-fertility as their parents and showed no genetic segregation.