‘Alchanheukchal’ is a single-cross hybrid waxy corn cultivar developed by using the inbred line ‘KBW16’ as the seed parent and ‘KBW23’ as the pollen parent. Yield trials were conducted in 2013 and 2015 followed by regional adaptability tests at six locations over three years (2018-2020). Recognized for its superior performance, it was designated as a new variety by the NICS in 2020. ‘Alchanheukchal’ contains 32.9 μg 100 g^-1 of anthocyanins, resulting in black-colored ears and exhibiting an intermediate ear shape. Its silking period was 74 days, equivalent to that of the standard variety ‘Ilmichal’. The ear length was 19.3 cm, similar to ‘Ilmichal’, while the kernel set rate was 94%, which was lower than that of ‘Ilmichal’. In terms of disease and pest resistance, including southern rust, northern corn leaf blight, and corn borer, as well as lodging resistance, ‘Alchanheukchal’ was comparable to ‘Ilmichal’. The number of ears and ear weight per 10a were 6,336 ears and 1,136 kg, respectively, which indicates a higher ear number but lower ear weight than ‘Ilmichal’. The 100-kernel weight was 27.7 g, smaller than that of ‘Ilmichal’. In sensory evaluation tests, the overall acceptability score was 4.7, which was lower than that of ‘Ilmichal’. The highest seed production efficiency was observed when the planting ratio of the seed parent to pollen parent was 2:1. However, because the silking date of the pollen parent occurred later, it was considered necessary to perform staggered sowing (Registration No. 10033).

‘Godangok 2’, a yellow sweet corn hybrid obtained by crossing inbred KSE14 (female) and KSE23 (male) varieties harboring the sugary enhancer (se) gene, was developed by the maize breeding team at the National Institute of Crop Science (NICS), Rural Development Administration, Korea, in 2020. Days to silking of ‘Godangok 2’ (65 days) was 3 days later than ‘Danok 3’ (check hybrid, 62 days). The ear length of ‘Godangok 2’ (18.9 cm) was similar to that of ‘Danok 3’, but it exhibited a higher kernel filling rate (97%). In addition, the lodging tolerance of ‘Godangok2’ was greater than that of ‘Danok3’. The number of ears per 10a in Godangok2 (6,177) was 4% higher than that in ‘Danok 3’, whereas ear weights (1,075 kg) were 4% lower. ‘Godangok 2’ had a high sugar content of 23.4° Brix, a thin pericarp thickness of 21.4 μm, and a light 100-kernel weight of 25.4 g compared to that of the check hybrid. ‘Godangok 2’ showed the highest seed yield of 270 kg/10a at a 4 (female):1 (male) planting ratio. Because ‘Godangok 2’ carries the recessive se gene, its unique qualities may be compromised by cross-pollination with other corn varieties (e.g., sh2, bt, wx types). Therefore, to maintain sweet corn quality, corn should be grown and harvested separately in time and space (Registration No. 10059).

‘KM7’, a maize hybrid for grain production, was developed for the Southeast Asian seed market by the maize breeding team of the National Institute of Crop Science (NICS), Rural Development Administration (RDA) in 2020. The hybrid, ‘KM7’, was bred by crossing two inbred lines, CL32 and 14K23. After a one-year yield trial in Dong Trieu, Vietnam, country adaptability trials were performed three times in three different countries (Vietnam, Cambodia, and Indonesia) in both 2019 and 2020. The seed type was flint-like and suitable for both food and feed. ‘KM7’ adapted well to conditions in northern Vietnam, northwestern Cambodia, and Central Java in Indonesia. The silking date of ‘KM7’ in Vietnam was 62 d, which was 1 d earler than that of LCH9, a leading cultivar in Vietnam. ‘KM7’ is an early maturing, high-grain yielding F1 hybrid that is also resistant to downy mildew. ‘KM7’ produced a grain yield of 842, 831, and 950 kg/10a in Vietnam, Cambodia, and Indonesia, respectively. This demonstrated a higher yield than that of the leading cultivars in each respective country. ‘KM7’ produced 26% more grain in Vietnam, 28% more in Cambodia, and 56% more in Indonesia than the respective control varieties (Registration No. 10034).

‘KM3’ is an F1 hybrid maize developed by the maize breeding team at the National Institute of Crop Science (NICS), Rural Development Administration (RDA), for the Southeast Asian seed market. This hybrid was obtained by crossbreeding two inbred lines—14K26 and 15VL027. The hybrid was evaluated in a crop-year yield trial in Cambodia, followed by country adaptability trials in Cambodia and Indonesia in 2016 and 2017, respectively. The flint-like seed type of ‘KM3’ makes it suitable for both food and feed, demonstrating its adaptability to Southeast Asia. ‘KM3’ exhibited early maturity, high grain yield as an F1 hybrid, and resistance to downy mildew. The silking date of ‘KM3’ was two days earlier than that of the leading cultivar ‘CP888’ in Cambodia, with a grain yield of 913 kg/10a, outperforming ‘CP888’ by 26% (Registration No. 9319).

‘KM5,’ a high grain yielding maize hybrid, was developed for the Southeast Asian seed market in 2018 by the maize breeding team of the National Institute of Crop Science (NICS), Rural Development Administration (RDA). ‘KM5’ was bred by crossing two inbred lines—14K23 and CL59. After a 1-crop year yield trial in Dong Trieu and Vietnam, country adaptability trials were performed in 2017 and 2018 in three different countries—Vietnam, Cambodia, and Indonesia. The seed type is flint-like and suitable for both food and feed. ‘KM5’ adapted well to northern Vietnam, northwestern Cambodia, and Central Java in Indonesia. It is an early maturing, high grain yield F1 hybrid that is also resistant to downy mildew. The silking date of ‘KM5’ in Vietnam is 74 days, which is the same as that of LCH9—a leading cultivar in Vietnam. ‘KM5’ produced a grain yield of 695, 764, and 678 kg/10a in Vietnam, Cambodia, and Indonesia, respectively, thus demonstrating a higher yield than the leading cultivar in each country. ‘KM5’ produced 2%, 27%, and 8% more grain than the respective control varieties in Vietnam, Cambodia, and Indonesia, respectively (Registration No. 8947).

‘Sinhwangok2’ is a single cross maize F₁ hybrid (Zea mays L.) that was developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA, in 2018. This yellow high-yielding intermediate maize hybrid was obtained by crossing between two inbred lines― KS214 and KS215. After advanced yield trials over two years in Suwon, a regional yield trial for ‘Sinhwangok2’ was conducted to evaluate its growth and yield at three different locations, from 2016 to 2018. ‘Sinhwangok2’ requires 72 days for silking and its plant height is 243 cm, similar to that of ‘Jangdaok’; its ear height ratio is 49%, like that of ‘Jangdaok’, and the hybrid shows resistance to lodging. The number of ears per 100 plants was found to be 100 and the ear length of ‘Sinhwangok2’ is 19.5 cm, which is shorter than that of ‘Jangdaok’. The weight of 100 seeds of ‘Sinhwangok2’ is 30.8 g, similar to that of ‘Jangdaok’. This hybrid shows moderate resistance to southern leaf blight (Bipolaris maydis). It has moderate resistance to European Corn Borer (Ostrinia nubilalis). The grain yield (i.e., 9.41 ton/ha) of ‘Sinhwangok2’ was found to be 13%, which is higher than that of ‘Jangdaok’. Seed production of ‘Sinhwangok2’ was 2.36 ton/ha and was considered acceptable due to a good synchronization of flowering period during crossing between the seed parent, KS214, and the pollen parent, i.e., KS215, in Yeongwol and F₁ seed yield. ‘Sinhwangok2’ can thus be a suitable cultivar for all plain areas in Korea and can possibly be cultivated via double cropping with winter forage crop because of their early maturity. (Registration No. 8963).

‘KM2’, a maize hybrid grain was developed for the Southeast Asian seed market by the maize breeding team of the Rural Development Administration (RDA), South Korea 2018. ‘KM2’ was bred by crossing two inbred lines, ‘15VL065’ and ‘KS155’. After a advanced yield trial at Dong Trieu, Vietnam, for the first cropping cycle in 2016, country adaptability trials were performed twice in three different countries: Vietnam, Cambodia, and Indonesia, in 2016 and 2017. ‘KM2’, a yellow intermediate seed for food and feed, adapts well to the northern Vietnam, northwestern Cambodia, and Central Java in Indonesia. It is an early maturing high-grain yield F1 hybrid. This hybrid is resistant to downy mildew, but not corn rust. The silking date of ‘KM2’ is 10 days earlier than that of ‘LVN10’, a leading cultivar in Vietnam. ‘KM2’ produced grain yields of 811 kg/10a, 845 kg/10a, and 783 kg/10a in Vietnam, Cambodia, and Indonesia, respectively, showing even higher grain yield than the countries’ respective leading cultivar. ‘KM2’ produced 61%, 17%, and 14% higher grain yield in Vietnam, Cambodia, and Indonesia, respectively, than their respective control cultivars (‘LVN10’, ‘CP888’, ‘P21’) (Registration No. 8192).

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).