‘Hwanggeummatchal’, a yellow waxy corn hybrid obtained by crossing inbred ‘KY37’ and ‘KY29’, was developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA, Korea, in 2017. The number of days to silking of ‘Hwanggeummatchal’ was 69 days after planting, 2 days earlier than ‘Ilmichal’ (a control variety). Plant height of ‘Hwanggeummatchal’ was 205 cm, lower than that of the control, and ear height ratio was 49%, which was lower than that of ‘Ilmichal’. Lodging resistance of ‘Hwanggeummatchal’ was similar to ‘Ilmichal’. The fresh ear yields were 6,389 ears in 10 a. The carotenoid content of ‘Hwanggeummatchal’ was 16.4 μg 100 g^-1 fresh weight, which was much higher than that of ‘Ilmichal’. The pericarp thickness was 41 μm. The sensory evaluation value was 5.7, and the flavor was excellent. The flowering period of its parental lines was well matched, and seed production was best at a planting ratio of maternal and paternal lines, 3:1. ‘Hwanggeummatchal’ is suitable to the whole country, except for Jeju-do. Seeds of ‘Hwanggeummatchal’ must be renewed annually because it is a single cross hybrid. If this hybrid is cultivated under high-density conditions, the ear size and the ratio of kernel set length to ear length will be lower than that of standard cultivation. Pest control should be performed for this hybrid because it is susceptible to corn borer (Registration No. 8136).

‘Godangok1’, a sweet corn hybrid obtained by crossing the inbred KSE13 (female) and KSE37 (male), was developed by the maize breeding team at the National Institute of Crop Science (NICS), Rural Development Administration, Korea, in 2016. ‘Godangok1’ has the sugary enhancer (se) gene, and the ear is yellow-white. The number of days to silking of ‘Godangok1’ was 59, similar to ‘Danok3’ (check variety), but ear length and the ratio of kernel set length to ear length (18.7 cm and 96%, respectively) were superior to those of ‘Danok3’. The resistance to Bipolaris maydis, Exserohilum turcicum, and Ostrinia furnacalis was similar to that exhibited by ‘Danok3’, whereas the lodging tolerance was stronger than that of ‘Danok3’. The fresh ear yield of ‘Godangok1’ was 6,530 ears, with 1,139 kg per 10a, and the sugar content was 20.8 °Brix. The hundred kernel weight was 27.4 g, smaller than that of ‘Danok3’. The flavor was excellent and assigned a sensory score of 5.7. Unique properties of ‘Godangok1’ coded by the recessive se gene are eliminated due to crosspollination when growing along with other types of corn such as general corn (sh, sh2, bt, etc.). Therefore, it must be isolated in time or space and harvested in order to produce high-quality sweet corn (Registration No. 7506).

In Korea, native or open pollinated corn varieties that were not improved before 1960 were cultivated. The 1960s was a step that created the foundation for the development of varieties. In 1962, systematic corn breeding was started when the synthetic type ‘Hwangok 2’ was distributed to farmers. The 1970s was the era of the change from synthetic varieties to hybrid ones, with a focus on the development of single-cross hybrids among the corn hybrids. The single-cross corn hybrid, ‘Suwon 19’, was an epoch-marking variety that had a unit-yield closer to that of advanced countries. The 1980s was a time when the breeding direction was changed from grain corn to silage because the corn cultivation area for silage increased rapidly with the government's livestock promotion policy, and the corn seed supply system of single-cross hybrids was established. In the 1990s, the era of globalization and the launching of imports of agricultural products, the living standards of consumers became more advanced, and the development system of corn varieties was established for various use purposes. As we entered the 2000s, it started the heyday of developing corn varieties, with 29 corn varieties of various use purposes and excellent cultivation stability developed. In the 2010s, the scope of corn variety development expanded from government or universities to private seed companies. Thus, the corn varieties in Korea have changed and developed in response to the situation of the times, and there are currently 110 corn varieties registered with Korea Seed & Variety Service (KSVS). In the future, vegetable corn is expected to be continuously developed, with functional ingredients such as strengthening vitamins, trace elements, and antioxidant components. Specialized grain corn, such as lysine and maltodextrin, will be developed and commercialized in order to improve the value added. In the case of silage corn, there will be varieties of early maturing and late planting adaptability, with no more than 110 days until maturity, suitable for the cropping system, such as second cropping and double cropping, as well as high digestion rate and nutrition varieties with high feed value, and excessive water tolerance corn varieties that adapt well to paddy fields. Furthermore, it is expected that corn varieties that adapt well to Southeast Asia, Latin America, and Africa will continue to be developed and supplied.

Baekgeumok, a sweet corn hybrid made by crossing inbred KSE15 and KSE21, was developed by the maize breeding team at the National Institute of Crop Science, Rural Development Administration in 2015. Baekgeumok silks at 63 days, similar to Danok3 (check variety). The plant height is 179 cm, higher than check variety, and the ear height is 105 cm, similar to check variety. Baekgeumok has an excellent lodging resistance. The fresh ear yields were 6,411 ears and 1,141 kg in 10 a. Pericarp thickness was 39 µm and sugar content was 19.5 °Bx. Sensory evaluation value was 6.1 and flavor was excellent. This hybrid can be cultivated in Gyeonggi-do, Gangwon-do, Chungcheongbuk-do, Gyeongsangbuk-do, and Gyeongsangnam-do. Seeds of Baekgeumok must be renewed annually, because this hybrid is a single cross hybrid. This sweet corn hybrid must be cultivated at least 200 m from areas with other corn varieties, because of their recessive gene. When cultivated at high density, the ear size and ratio of kernel set length / ear length will be lower in this hybrid than in standard cultivars. This hybrid requires pest control because it is susceptible to corn borer infestation. Drainage management is important in the rainy season. (Registration No. 6725)

‘KM1’, a corn hybrid was developed for seed export to Southeast Asia by the maize breeding team of the National Institute of Crop Science (NICS), RDA in 2016. The hybrid ‘KM1’ was obtained by crossing two inbred lines, ‘KS155’ and ‘15VL060’. After yield trials at Dong Trieu, Vietnam for one year, country adaptability trials were subsequently carried out in three countries (Vietnam, Cambodia, and Indonesia) in 2016. ‘KM1’ is a white-yellow and dent-like corn, and the plant adapts to the northern part of Vietnam and northwestern part of Cambodia; and the corn can be used as food and feed. The plant is fast flowering and has strong lodging tolerance and resistance to southern leaf blight and downy mildew. Silking date of ‘KM1’ is 5 days earlier than that of Vietnam’s leading cultivar ‘LVN10’. The grain yield of ‘KM1’ is 879 kg/10a in Vietnam, which is 22% higher than that of LVN10, and 914 kg/10a in Cambodia, which is 5% higher than that of Cambodia’s leading cultivar ‘CP888’. This hybrid requires the implementation of disease control measures because it is susceptible to corn rust. (Registration No. 7507).

‘Hwangdaok’, a new maize F1 hybrid (Zea mays L.), was developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2016. The high-yielding yellow dent hybrid named ‘Hwangdaok’ was obtained by crossing between two inbred lines, ‘KS203’ and ‘KS190’. After advanced yield trial in Suwon in 2012, regional yield trial was subsequently carried out to evaluate the growth and yield of ‘Hwangdaok’ at three different locations from 2014 to 2016. The number of days to silking of ‘Hwangdaok’ is 76. The plant height is 262 cm and ear height ratio is 51%, which are similar to those of ‘Jangdaok’. It has resistance to lodging. The number of ears per 100 plants is 95. The ear length is 21.3 cm and weight of 100 seeds is 34.7 g, similar to those of ‘Jangdaok’. It has moderate resistance to southern leaf blight (Bipolaris maydis) and European corn borer (Ostrinia nubilalis). The grain yield (10 ton/ha) of ‘Hwangdaok’ is 6% higher than that of ‘Jangdaok’. The seed production rate of ‘Hwangdaok’ is acceptable due to good synchronization of flowering period during crossing between the seed parent, KS203, and the pollen parent, KS190, in Yeongwol. F1 seed yield was 1.68 ton/ha. ‘Hwangdaok’ can be a suitable cultivar to plain areas in Korea. (Variety registration No. 7502).

‘Daanok’, 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 2013. The high-yielding hybrid, named ‘Daanok’ was bred by crossing between two inbred lines, ‘KS174’ and ‘KS175’. It is a yellow semi-flint maize hybrid (Zea mays L.). After preliminary yield trial and advanced yield trial of Daanok 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 2011 to 2013. The silking date of Daanok is earlier than that of the check hybrid, ‘Jangdaok’. The plant height of Daanok is 229cm, similar to Jangdaok, and its ear height ratio is similar with that of Jangdaok.It has resistance to lodging. There are much of the No. of ear per 100 plants. The ear length of Daanok is similar with that of Jangdaok. The weight of 100 seeds of Daanok is the same with that of Jangdaok. It has strong resistance to northern leaf blight (Exserohilum turcicum) and southern leaf blight (Bipolaris maydis). It has strong resistance to ear lot. It has moderate resistance to corn borer. The grain yield (7.34 ton/ha) of Daanok was 23% higher than that of Jangdaok. The seed production of Daanok has gone well due to a good synchronization of flowering period during crossing between the seed parent, KS174, and the pollen parent, KS175, in Yeongwol and F1 seed yield was 2.38 ton/ha. Daanok would be a suitable cultivar to all plain area in Korea.

A ‘Hayanchal95’, a new waxy corn hybrid, is a single cross hybrid developed by the maize breeding team at the National Institute of Crop Science (NICS), Rural Development Administration(RDA) in 2011. This hybrid was made by crossing between seed parent KW44 and pollen parent KW35. Days to silking of Hayanchal95 was three days earlier than Ilmichal, a check hybrid. Ear length and diameter of Hayanchal95 were 18.3 cm and 4.1 cm, respectively. The ratio of kernel set length to ear length was 90% and lower than Ilmichal. Its quality characteristics like amylopectin content, hardness of kernels, and value of sensory evaluation were not significantly different from Ilmichal except grain length. Resistance to corn borer and lodging tolerance of Hayanchal95 were better than Ilmichal. The number of fresh ears was similar to those of Ilmichal and weight of fresh ears was lower than Ilmichal in regional yield trials (RYT) from 2009 to 2011. Although flowering time of its parent lines was good match during crossing between the seed and pollen parents, seed production was low. It is adaptable to the whole country. Plant variety protection right of ‘Hayanchal95’ was registered in July 2014, and its grant number is 5110.

A single cross hybrid, ‘Godangok’, is a yellow sweet corn developed by the maize breeding team at the National Institute of Crop Science (NICS), Rural Development Administration (RDA) in 2011. This hybrid was produced by crossing between KSE5 and KSE19. KSE5 is a seed parent and KSE19 is a pollen parent of Godangok. Days to silking of Godangok was 3 days later than Danok 3, a check hybrid. Ear length and diameter of Godangok were 17.6 cm and 4.4 cm, respectively. The ratio of kernel set length to ear length was 87.1%. These characteristics of ear were similar to those of the check hybrid. However, the Degree Brix was 24.3 °Bx, higher than the check hybrid, 14.1 °Bx. Lodging tolerance of Godangok was better than the check hybrid. The number and weight of fresh ear of Godangok were similar to those of the check hybrid in regional yield trials (RYT) from 2009 to 2011. Seed production of this hybrid is good due to good match between the seed and pollen parent. It is adaptable to the whole country. Plant variety protection right of ‘Godangok’ was registered in July 2014, and its grant number is 5094.

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.