Rye has been a major winter forage crop in Korea. Varietal improvement of rye has been practiced either by hybrid or population breeding systems. Hybrid breeding offers important advantages over population breeding since it is normally a cross-pollinated crop. The hybrid breeding in rye has been possible since cytoplasmically inherited forms of male sterility (CMS) and corresponding nuclear restorer genes were found. The objectives of this research were to develop the maintainer and restorer lines of Korean inbred lines and to estimate the effect of 'Pampa' type of CMS cytoplasm on yield and its related characteristics. For easy discrimination of male-sterile status of plants, anther scoring and the restore index system in which seed-setting and pollen quantity of viability were taken into account were established. High significant correlation between pollen quantity and pollen viability was found. For "Pampa" cytoplasm, four of 14 Korean inbred lines tested turned out to be a maintainer but no restorer was found. But for "235b" CMS cytoplasm, seven inbred lines acted as complete restorers. The Korean inbred rye lines acted mainly as maintainers in "Pampa" cytoplasm but acted mainly as restorer in "235b" cytoplasm. The 'Pampa' cytoplasm inducing male sterility reduced cohn length and plant height and increased the number of tiller, so forage yield and grain yield were enhanced. However, heading date was slightly delayed compared to the normal cytoplasm.elayed compared to the normal cytoplasm.

Rye breeding using F1 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 F2 populations showed that the segregation of self-fertile and sterile plants in F2 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 F2 plants showed almost the same self-fertility as their parents and showed no genetic segregation

This experiment was conducted to evaluate the effect on evapotranspiration and yield of soybean according to different soil water conditions, and to find the optimum time and amount for irrigation in soybean cultivation. The difference between potential evapotranspiration (PET) and maximum evapotranspiration (MET) during growing season of soybean planted in lysimeter was higher during reproductive stage than during vegetative one. The maximum crop coefficient was obtained at beginning seed stage of soybean. Soil water coefficient of irrigation treatment was higher than that of non-irrigation treatment during soybean growth stage in field experiment. Grain yield was highest in lysimeter due to its high water use efficiency and evapotranspiration rate.