In 2020, ‘Sodammi’ was developed as a sweetpotato with a slightly moist texture, excellent palatability, and appearance. It was derived from a cross between ‘Hogammi’ (IT327288), which has a slightly moist texture and excellent palatability, and ‘Kyushu No. 121’ (IT309496), which has a yellow flesh and good appearance. The storage roots of ‘Sodammi’ have a purple-red skin, yellow flesh, and an ovate shape. ‘Sodammi’ storage roots exhibit a slightly moist texture and are more tender than those of the check variety ‘Jinhongmi’. The sweetness of steamed storage roots of ‘Sodammi’ was 19.1, which was 24.8% higher than that of ‘Jinhongmi’. Palatability of steamed storage of ‘Sodammi’ was better than that of ‘Jinhongmi’. The marketable storage root yield of ‘Sodammi’ was 19.6 MT/ha during the normal season culture. ‘Sodammi’ is moderately resistant to Fusarium wilt and root-knot nematodes. ‘Sodammi’ had very good storability, as there was almost no decay rate and no internal cavitation during long-term storage. Cultivation of the ‘Sodammi’ variety is expected to expand considerably, as it has characteristics favored by consumers, farmers, and distributors due to its excellent palatability, appearance, and storability (Registration No. 8789).

‘Hogammi’ was developed as a sweetpotato variety with β-carotene content and excellent palatability in 2015. It was derived by crossing ‘AB95007-2’, which has good shape and storage root yield, and ‘Annoimo’, which has light orange flesh and good palatability. ‘Hogammi’ had storage roots with long elliptical shape, red skin, and light orange flesh. The texture of the steamed storage root of ‘Hogammi’ was intermediate or slightly moist, and it was more tender than that of ‘Yulmi’. The soluble solid content of the steamed storage roots of ‘Hogammi’ was 29.7 °Brix, which was 10.8% higher than that of ‘Yulmi’. The palatability of the steamed storage roots of ‘Hogammi’ was better than that of ‘Yulmi’. The β-carotene content of the storage roots of ‘Hogammi’ was 9.8 mg/100 g dry weight. ‘Hogammi’ was moderately resistant to Fusarium wilt and root-knot nematode. In ‘Hogammi’, the number of marketable storage roots per plant and the average weight of marketable storage root were 3.4 and 133 g under culture in the normal season, respectively. The marketable storage root yield of ‘Hogammi’ was 24.1 MT/ha under culture in the normal season, which was 4% higher than that of ‘Yulmi’. The yield of marketable storage root over 50 g of ‘Hogammi’ was 14.5 MT/ha under culture in the early season, which was 39.8% lower than that under culture in the normal season. ‘Hogammi’ was more suitable for culture in the normal season (Registration No. 6466).

The 24 potato cultivars grown in three regions with different cultivation environments were investigated genotype and environment interaction (GEI) using the Additive Main Effects and Multiplicative Interaction (AMMI), and Genotype main effect and genotype by environment interaction (GGE) biplot model analysis. Potato yield was highly related to environment and GEI factors but the number of tubers and dry matter content were related to the genotype factor. Potato yield was the highest in ‘Seohong’ in Gangneung, ‘Dejima’ in Jinbu area, and ‘Saebong’ in Daegwallyeong area. As a result of analysis of GEI effect between genotypes and environment, ‘Seohong’ in yield, ‘Daejima in tuber, and ‘Goun’ in dry matter content were superior and were stable. The ‘Seohong’, which has the highest yield and stability, showed promising results and can substitute the ‘Superior’ variety. The ‘Goun’ was selected as a chip potato processing grade to replace ‘Dejima’, which currently is the major processing grade. Therefore, as a result of analysis of AMMI and GGE biplot models of agricultural traits of potatoes showed that the cultivation environment has greatest influence on the yield. Therefore, proper site selection for the desired cultivar is necessary for best results. Though it is also important to select the best genotype with a high dry matter content.