‘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).

‘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).