‘Dacheongok’, 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 2016. The high-yielding hybrid, named ‘Dacheongok’ was bred by crossing between two inbred lines, ‘KS197’ and ‘KS202’. It is a yellow dent maize hybrid. After advanced yield trial of ‘Dacheongok’ in Suwon for one year, regional yield trial was subsequently carried out for evaluation of its growth and yield at four different locations from 2014 to 2016. The days to silking of ‘Dacheongok’ are 80, similar to ‘Kwangpyeongok’. The plant height of ‘Dacheongok’ is 267 cm, similar to ‘Kwangpyeongok’, and its ear height ratio is 51%, similar with that of ‘Kwangpyeongok’. It has resistance to lodging. The stay-green of ‘Dacheongok’ is not different with that of ‘Kwangpyeongok’. The number of ear per 100 plants of ‘Dacheongok’ is 95, similar to ‘Kwangpyeongok’. The ear length of ‘Dacheongok’ is 18.6 cm, longer than that of ‘Kwangpyeongok’. The weight of 100 seeds of ‘Dacheongok’ is 29.8 g, similar to that of ‘Kwangpyeongok’. It has moderate resistance to southern leaf blight (Bipolaris maydis). It has moderate resistance to European Corn Borer (Ostrinia nubilalis). The dry matter yield (23.69 ton/ha) of ‘Dacheongok’ was 10% higher than that of ‘Kwangpyeongok’. The TDN (Total Digestible Nutrients) yield (16.11 ton/ha) of ‘Dacheongok’ was 7% higher than that of ‘Kwangpyeongok’. The seed production of ‘Dacheongok’ was acceptable due to a good synchronization of flowering period during crossing between the seed parent, KS197, and the pollen parent, KS202, in Yeongwol and F₁ seed yield was 2.46 ton/ha. ‘Dacheongok’ would be a suitable cultivar to all plain area in Korea. (Variety registration No. 7054)

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.