Potato late blight caused by the fungus Phytophthora infestans is one of the most important diseases worldwide. Developing potatoes with resistance to late blight through breeding programs is a key research interest in Korea. ‘Mangang’ was bred for late blight resistance through a breeding program at the Highland Agriculture Research Institute of National Institute of Crop Science. The population derived from the cross between ‘Atlantic’ as the female parent, which has excellent chipping quality and ‘CIP393371.159’ as the male parent, a late blight-resistant clone introduced from International Potato Center (CIP), was selected. In ‘Mangang’, the plant maturity occurs late and the growth habit is of the erect type. The tuber shape is round and eye-depth is medium. The skin color of ‘Mangang’ is light yellow; however, there are pink spots around the eyes of the tuber, and the flesh color is white. Leaf color is green and flower color is light-purple. ‘Mangang’ exhibits resistance to early blight (Alternaria solani) and leaf roll virus (PLRV). In addition, it has moderate resistance to common scab (Streptomyces scabies). The response to late blight was evaluated in a non-agrochemical treated field for five years between 2012 and 2016; ‘Mangang’ exhibited resistance to late blight. The mean AUDPC (Area Under Disease Progress Curve) values of ‘Mangang’ and ‘Atlantic’ were 165.5 and 795.8, respectively. Total tuber yield from the non-agrochemical application trial at three regions during the five years was 40.3 ton/ha; this was 40.4% higher than that from ‘Atlantic’. The dry matter content of ‘Mangang’ was 21.3%, which was slightly higher than that of ‘Atlantic’. The chip color was 66.5, and the chip processing quality of ‘Mangang’ was at a level similar to that of ‘Atlantic’ (Registration No. 9312).

‘Saebong’ is a double cropping potato variety bred by the Highland Agriculture Research Institute, NICS, RDA, in 2010. Although the major double-cropped potato cultivar of Korea, cv. Dejima, with a dormancy period of 50-60 days after harvest was introduced in 1978, it is susceptible to physiological disorders, such as abnormal tubers and cracking, and common scab. The ‘Chubaek’ variety matures very early and has a dormancy period similar to that of cv. Dejima, yet it is highly susceptible to potato virus Y and has a low dry matter content. ‘Saebong’ was obtained by crossing ‘Daegwan2-8’ with ‘DH9-231’ in 2002. Seedling and line selections were performed from 2003-2004, and yield trials were carried out from 2005-2006 in Gangneung and Pyeongchang. Regional yield trials were conducted in spring and autumn in Namhae, Jeju, and Gangneung from 2007-2008 and in Muan, Jeju, and Gangneung in 2009. This variety produces many white flowers and berries, narrow green leaflets and petioles, and round tubers with beige-colored skin and white-colored flesh. Its dormancy period, when stored at 20℃, was 50-60 days after harvest in spring, similar to cv. Dejima and Chubaek. The average tuber yields in spring and autumn regional trials were 40.4 and 30.5 ton⋅ha^-1, respectively. It is susceptible to common scab but highly resistant to potato leafroll virus and potato virus Y. Its dry matter content was 21.56% and 20.60% in spring and autumn, respectively (similar to those of cv. Atlantic and cv. Goun). It produces brighter colored potatoes and can be used to process potato chips and table stock after autumn cultivation in the potato double cropping area of Korea (Registration No. 4873).

A new double cropping potato variety, ‘Gangseon’, was bred by the Highland Agriculture Research Institute, National Institute of Crop Science (NICS), RDA, Korea, in 2016. ‘Gangseon’ was obtained from the cross between ‘Daegwan1-83’ and ‘Chubaek’ in 2006. Seedling and line selection was performed from 2008 to 2009, and preliminary and advanced yield trials were carried out with ‘Gangseon’ from 2010 to 2013 in Gangneung city. The regional yield trials were conducted in Gangneung, Muan, and Jeju from 2014 to 2016. ‘Gangseon’ has light purple flowers, green narrow leaflets and petioles with medium anthocyanin coloration, round tubers with yellow russet skin, and yellow flesh. The dormancy of ‘Gangseon’ stored in 20 ℃ was 60-70 days after harvesting, which is longer than those of ‘Dejima’ and ‘Chubaek’, but shorter than that of ‘Superior’. The average yields of tubers in the spring and fall seasons were 36.6 and 21.2 ton⋅ha^-1, respectively, in the regional yield trials. It is susceptible to common scab and potato virus Y, but has high resistance to potato leaf roll virus, potato virus X, early blight, and late blight. The dry matter contents were 22.1% in spring and 19.8% in autumn. The adaptation area of ‘Gangseon’ is the southern coastal area, including Jeju Island, Korea. The plant variety protection right of ‘Gangseon’ was registered in April 2020, and its grant number is 8081.

Abstract‘Daegwang’ was developed in a potato breeding program at the Highland Agriculture Research Institute, National Institute of Crop Science, Rural Development Administration, South Korea. It was selected from the hybrid ‘Haryeong’בP03404-1’ from 2007. In 2011-2012, the major agronomic characteristics of this variety were evaluated in Gangneung for spring cultivation and Pyeongchang for summer cultivation as clone number ‘P07917-4’. ‘P07917-4’ was renamed as ‘Daegwan 1-127’, and regional yield trials for this clone were conducted in Cheongju, Naju, Gangneung, and Pyeongchang in 2013-2015. This cultivar was registered as ‘Daegwang’, based on its key agronomic characteristics, including drought tolerance, late blight resistant, and high yield. It has medium maturity and a semi-erect growth habit. ‘Daegwang’ has a round to short oval tuber shape, shallow eye-depth, yellow skin color, and white flesh color. Its leaf color is green, and its white flowers bloom abundantly. This cultivar is resistant to potato late blight but susceptible to potato common scab. The incidences of hollow heart and internal brown spot were low. However, the frequency of tuber cracking was high, at about 6.0% in summer cultivation in Pyeongchang. In the regional yield trials, ‘Daegwang’ had an average tuber yield of 34.1 ton/ha, which was 6.2% higher than that of ‘Sumi’, and its dry matter content was 16.8%. Boiled ‘Daegwang’ tubers have a viscous-floury texture and a pleasant taste. ‘Daegwang’ is expected to be produced as a table potato. (Registration No. 7664).