‘Dapyeongok’, a new maize F₁ hybrid (Zea mays L.), is developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2010. The high-yielding hybrid, named ‘Dapyeongok’ was bred by crossing between two inbred lines, ‘KS158’ and ‘KS155’. It is a yellow dent maize hybrid (Zea mays L.). After preliminary yield trial and advanced yield trial of Dapyeongok in Suwon for two years, regional yield trial of that was subsequently carried out for evaluation of its growth and yield at three different locations from 2008 to 2010. The silking date of Dapyeongok is the same with that of the check hybrid, ‘Jangdaok’. The plant height of Dapyeongok is similar to Jangdaok, and its ear height ratio is the same with that of Jangdaok. It has resistance to lodging. The ear length of Dapyeongok is shorter than that of Jangdaok. The weight of 100 seeds of Dapyeongok is lighter than that of Jangdaok. It has strong resistance to northern leaf blight (Exserohilum turcicum) and southern leaf blight (Bipolaris maydis). It has moderate resistance to black streaked dwarf virus (BSDV), ear lot and corn borer. The grain yield (8.6 ton/ha) of Dapyeongok was 8% higher than that of Jangdaok. The seed production of Dapyeongok has gone well due to a good synchronization of flowering period during crossing between the seed parent, KS158, and the pollen parent, KS155, in Yeongwol and F₁ seed yield was 2.8 ton/ha. Dapyeongok would be a suitable cultivar to all plain area in Korea.

Cheongdaok, a new single maize (Zea mays L.) variety, was developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2010. This high-yielding hybrid was produced by crossing two inbred lines, KS159 and KS155. KS159 is the seed parent and KS155 is the pollen parent of Cheongdaok. It is a yellow dent maize hybrid. After the preliminary yield trial and advanced yield trial of Cheongdaok in Suwon for two years, the regional yield trial was subsequently carried out for evaluation of its growth characteristics and yield at four different locations from 2008 to 2010. The silking date of Cheongdaok is one day earlier than that of the check hybrid, Kwangpyeongok. Compared to Kwangpyeongok, the Cheongdaok show short in plant height and low in ear height ratio. It has resistance to lodging. The stay-green degree and the ear ratio of Cheongdaok are similar to Kwangpyeongok. It has moderate resistance to southern leaf blight (Bipolaris maydis) and strong resistance to northern leaf blight (Exserohilum turcicum). It has moderate resistance to black streaked dwarf virus (BSDV), ear lot, and corn borer. The dry matter yield 20.24 ton/ha and the total digestible nutrient (TDN) yield (13.80 ton/ha) of Cheongdaok were similar to Kwangpyeongok. The grain yield (8.51 ton/ha) of Cheongdaok was higher than that of Jangdaok. The seed production of Cheongdaok was well processed due to a good synchronization of flowering period during crossing between the seed parent KS159 and the pollen parent KS155, and the F1 seed yield was 1.8 ton/ha in Yeongwol.