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).

In 2019, ‘Bodeuremi’ was developed as a high-yielding sweetpotato variety with good palatability. It was derived from a cross between ‘MI2006-58-02’ with high yield and ‘Beniharuka’ (IT309504) with good palatability. The storage roots of ‘Bodeuremi’ have a red skin, light orange flesh, and an ovate shape. When steamed, ‘Bodeuremi’ storage roots exhibit a moist texture and are more tender than those of the check variety ‘Pungwonmi’. The sugar content of steamed ‘Bodeuremi’ storage roots was 33.4 mg/100 g dw, which was 6.0% higher than that of ‘Pungwonmi’. The marketable yield of ‘Bodeuremi’ storage roots was 30.3 MT/ha in the early season culture, which was 4.5% higher than that of ‘Pungwonmi’ with high yield in the early season culture. ‘Bodeuremi’ is resistant to root-knot nematode and moderately resistant to Fusarium wilt. ‘Bodeuremi’ is expected to contribute to increased income of sweetpotato growers as it has high cultivation stability and can be shipped at a time when the market price is high owing to its high yield in the early cultivation.

In order to select sweetpotato varieties with excellent tip characteristics, we investigated the appearance, yield, and functional compounds in 32 domestic sweetpotato varieties. During the cultivation period, the total production of sweetpotato tips among the different variety ranged from 1,780 to 9,923 g/m², with that of the Gogeonmi variety being the highest. The lutein content among varieties ranged from 21.7 to 47.0 mg/100 g and was highest in the Juhwangmi variety, whereas the ß-carotene content ranged from 25.5 to 183.4 mg/100 g and was highest in the Hayanmi variety. The total polyphenol content ranged from 30.7 to 74.4 mg CAE/g, and it was high in the Pungwonmi, Daeyumi, and Dahomi varieties at 74.4, 73.8, and 72.9 mg CAE/g, respectively, whereas the DPPH radical scavenging activity of tips ranged from 88.6% to 91.6%, with Gogeonmi and Healthymi showing the highest value of 91.6%. ABTS radical scavenging activity was found to be lowest in the Yeonjami variety at 86%, whereas the remaining 31 varieties showed values in excess of 96%. ABTS radical scavenging activity showed a high positive correlation with total polyphenol content. On the basis of these analyses, we identified Juhwangmi with high lutein content, Hayanmi with high beta-carotene content and high yield, and Gogeonmi with high DPPH radical scavenging activity and high yield, as being suitable varieties for tip cultivation. We anticipate that these sweetpotato varieties with excellent tip characteristics will be used as parents for the breeding of varieties for vegetable use.

AbstractIn 2016, ‘Jinyulmi’ was developed as a sweetpotato variety with good palatability and high marketable storage root yield. It was derived from a cross between ‘Sinchunmi’ and ‘Jeonmi’. ‘Sinchunmi’ is small, with an average storage root weight of 141 g and an average number of marketable storage roots of 3.4. ‘Jeonmi’ has a high storage root yield of 26.2 MT/ha and intermediate steamed storage root texture. The storage roots of ‘Jinyulmi’ are elliptical and have red skin and yellow flesh. ‘Jinyulmi’ is resistant to Fusarium wilt and moderately resistant to root-knot nematode. The steamed storage root texture of ‘Jinyulmi’ is intermediate and more tender than that of check variety ‘Yulmi’. The sweetness of ‘Jinyulmi’ steamed storage roots was 13.1, which was 12.9% higher than that of ‘Yulmi’. ‘Jinyulmi’ steamed storage roots are also more palatable than those of ‘Yulmi’. The marketable storage roots yield of ‘Jinyulmi’ was 24.2 MT/ha in the early season culture, which was 26.0% higher than that of ‘Yulmi’. Its average marketable storage root weight was 137 g in the normal season culture, which was lower than that of ‘Yulmi’, but the number of marketable storage roots per plant was 3.6, which was higher than that of ‘Yulmi’. The marketable storage root yield of ‘Jinyulmi’ was 28.6 MT/ha in the normal season culture, which was 19.7% higher than that of ‘Yulmi’. ‘Jinyulmi’ is, therefore, suitable for both early and normal season cultures (Registration No. 7053).