‘Saebonghwang’ was developed as a mid-late ripening rice variety with good cultivation stability and yield in transplanting and under direct seeding cultivation. It was bred by backcrossing ‘Hopum’, which has excellent cultivation stability and adaptability to direct seeding, as a repeat parent, and ‘Hitomebore,’ a Japanese rice variety with excellent taste, as a donor. The heading date of ‘Saebonghwang’ was August 11 under ordinary planting, which is two days earlier than that of ‘Nampyeong’, and August 13 under wet-direct seeding cultivation, which is the same as that of ‘Dongan’. ‘Saebonghwang’ had a culm length of 74 cm under wet-direct seeding cultivation, which is larger than that of ‘Dongan’ (69 cm), and had good cultivation stability, including lodging resistance. ‘Saebonghwang’ is resistant to bacterial leaf blight and rice stripe virus and shows moderate resistance to rice blast. Furthermore, ‘Saebonghwang’ has better grain appearance, superior taste and better milling characteristics than ‘Nampyeong’. The yield of ‘Saebonghwang’ when cultivated under ordinary planting, wet-direct seeding, and double cropping was 5.65, 5.37, and 5.37 MT/ha, respectively. Under wet direct sowing by drone cultivation, ‘Saebonghwang’ showed good initial survival rate and cultivation stability. The yield was 4.49 MT/ha, slightly lower than that obtained under transplanted cultivation (5.03 MT/ha), but was not statistically different; therefore, ‘Saebonghwang’ was adjudged to be adaptable to drone wet-direct seeding. ‘Saebonghwang’ can be used in various ways to suit the working conditions of farms, increase farm work efficiency, and expand the area of wet direct-seeding cultivation (Registration No. 9171).

‘Jonong’ is an early maturing whole crop silage (WCS) japonica rice cultivar characterized by a short growth duration and numerous spikelets. It was developed to enhance the adaptability of WCS rice to double-cropping systems. ‘Jonong’ is derived from a cross between ‘Binhae Col.#1’ and ‘Deuraechan’; ‘Binhae Col.#1’ is a semi-early maturing China rice germplasm with numerous spikelets on dense panicles, whereas ‘Deuraechan’ is a high-yielding japonica rice cultivar with numerous spikelets on long panicles. To diversify the genetic variation and shorten the breeding period, an anther culture method was applied to the F₁ plants. ‘Jonong’ was selected through the pedigree method, yield trials, and local adaptability tests, with a high selection pressure for short growth duration and high biomass. The average heading date of ‘Jonong’ was August 1^st, which is 11 days earlier than that of ‘Nokyang’, the standard cultivar for WCS rice. Moreover, the growth duration of ‘Jonong’ is the shortest among all Korean WCS rice cultivars. The culm length of ‘Jonong’ is 88 cm, which 4 cm longer than that of ‘Nokyang’ and the highest among all Korean early maturing rice cultivars. ‘Jonong’ has 149 spikelets per panicle, which is 30 more than that of ‘Nokyang’, and is the highest among all Korean early maturing rice cultivars. ‘Jonong’ exhibits stable premature heading and is tolerant to lodging. It is moderately resistant to leaf blast and resistant to the rice stripe virus. The feed value of ‘Jonong’ in terms of total digestible nutrients is good and comparable to that of ‘Nokyang’. Furthermore, compared with ‘Nokyang’, ‘Jonong’ shows a similar level of dry matter yield and a higher rough rice yield. Therefore, ‘Jonong’, an early maturing WCS japonica rice with short growth duration and numerous spikelets, would be suitable for cultivating in winter forage crop-rice double cropping systems (Registration No. 7274).

‘Sinjinbaek’ is a bacterial blight (BB)-resistant, mid-late maturing rice cultivar with high grain quality. To diversify the resistance genes and enhance the resistance of Korean rice cultivars against BB, ‘Sinjinbaek’ was developed from a cross between ‘Iksan493’ (cultivar name ‘Jinbaek’) and the F₁ cross between ‘Hopum’ and ‘HR24670-9-2-1’ (‘HR24670’). ‘Jinbaek’ is a BB-resistant cultivar with two BB resistance genes, Xa3 and xa5. ‘Hopum’ is a high grain quality cultivar with the Xa3 resistance gene. ‘HR24670’ is a near-isogenic line that carries the Xa21 gene, a resistance gene inherited from a wild rice species O. longistaminata, in the genetic background of japonica elite rice line ‘Suweon345’. ‘Sinjinbaek’ was selected through the pedigree method, yield trials, and local adaptability tests. Using bioassay for BB races and DNA markers for resistance genes, three resistance genes, Xa3, xa5, and Xa21, were pyramided in the ‘Sinjinbaek’ cultivar. ‘Sinjinbaek’ exhibited high-level and broad-spectrum resistance against BB, including the K3a race, the most virulent race in Korea. ‘Sinjinbaek’ is a mid-late maturing rice cultivar tolerant to lodging. It has multiple disease resistance against BB, rice blast, and stripe virus. The yield of ‘Sinjinbaek’ was similar to that of ‘Nampyeong’. ‘Sinjinbaek’ showed excellent grain appearance, good taste of cooked rice, and enhanced milling performance, and we concluded that it could contribute to improving the quality of BB-resistant cultivars. ‘Sinjinbaek’ was successfully introgressed with the Xa21 gene without the linkage drag negatively affecting its agronomic characteristics. ‘Sinjinbaek’ improved the resistance of Korean rice cultivars against BB by introgression of a new resistance gene, Xa21, as well as by pyramiding three resistance genes, Xa3, xa5, and Xa21. ‘Sinjinbaek’ would be suitable for the cultivation in BB-prone areas since it has been used in breeding programs for enhancing plants’ resistance to BB (Registration No. 7273).

‘Haepum’ is a bacterial blight-resistant, medium maturing rice cultivar with high grain quality. It was derived from a cross between ‘Iksan493’ (cultivar name ‘Jinbaek’) and the F₁ cross between ‘Iksan495’ (‘Dacheong’) and ‘Iksan496’ (‘Jungmo1005’). Of these three cultivars, ‘Jinbaek’ is a bacterial blight-resistant mid-late maturing rice cultivar with high grain quality, ‘Dacheong’ is a mid-late maturing rice cultivar with multiple resistance to disease and insects, and ‘Jungmo1005’ is a mid-late maturing rice cultivar with lodging tolerance. To develop fixed lines, the anther culture method was applied to F₁ plants. The cultivar ‘Haepum’ was selected using the pedigree method, yield trials, and local adaptability tests. The heading date of ‘Haepum’ was August 11^th, three days earlier than that of ‘Nampyeong’ cultivar. Haepum’ is a cultivar tolerant to lodging and it has short culms. Due to its low rate of viviparous germination, ‘Haepum’ could be useful for preventing pre-harvest sprouting in cultivation of medium maturing rice in the southern plain area of Korea. ‘Haepum’ carries two bacterial blight resistance genes (Xa3 and xa5), and in our study, it exhibited high-level and broad-spectrum resistance against bacterial blight, including K3a, the most virulent race in Korea. ‘Haepum’ is also resistant to the rice stripe virus and moderately resistant to rice blast. The yield of ‘Haepum’ was similar to that of ‘Nampyeong’. ‘Haepum’ showed excellent grain appearance and good taste of cooked rice, and therefore it could contribute to the development of bacterial blight-resistant rice cultivars of improved quality. ‘Haepum’ would be suitable for cultivation in the southern plain area of Korea as well as in bacterial blight-prone areas. (Registration No. 6068)

Joil’ is a multiple disease resistant early maturing rice cultivar with high grain quality. ‘Joil’ was derived from a single cross between ‘Unbong37’ (cultivar name ‘Unmi’) and ‘HR23156-26-2-3-5’. ‘Unmi’ is an early maturing rice cultivar with high grain quality and resistance to rice blast and stripe virus. ‘HR23156-26-2-3-5’ is an early maturing elite rice line with lodging resistance and cold tolerance. ‘Joil’ was selected through the pedigree method, yield trials, and local adaptability tests. ‘Joil’ was an early maturing rice. The heading date of ‘Joil’ was July 16 in early transplanting cultivation, which was 2 days later than that of ‘Jopyeong’. ‘Joil’ was a lodging resistance rice with a short culm and showed better tolerance to viviparous germination than that of ‘Jopyeong’. ‘Joil’ was a multiple disease resistant rice with resistance against rice blast, bacterial blight, and stripe virus. ‘Joil’ showed higher yield in both early and late-transplanting cultivations than those of the standard rice cultivars ‘Jopyeong’ and ‘Geumo’. ‘Joil’ had enhanced grain quality under high temperature ripening conditions in early transplanting cultivation. The cooked rice had good grain appearance and taste attributes, and this cultivar had a higher head rice ratio than that of ‘Jopyeong’. ‘Joil’, a multiple disease resistant early maturing rice cultivar with high grain quality, would be suitable for early transplanting cultivation in the southern plain area (Registration No. 6792).

‘Jungmo1045’, a multi-resistant japonica rice cultivar developed from a cross between ‘Hanggeumnuri’ having a good eating-quality and high yield and ‘SR30071’ having brown planthopper (BPH) resistance, was developed by the rice breeding team of NICS, RDA in 2015. This cultivar has about 121 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It has 73cm culm length and 22cm panicle length. In reaction to biotic and abiotic stresses, it shows resistance to bacterial blight pathogen races from K1 to K3, stripe virus and brown planthopper. The milled rice of ‘Jungmo1045’ exhibits translucent, relatively clear non-glutinous endosperm and medium short grain. It has good palatability of cooked rice compared with ‘Nampyeongbyeo’. The milled rice yield performance of this variety is about 5.74 MT/ha in local adaptability test for three years. ‘Junngmo1045’ would be useful genetic resources for multi-resistance breeding program against disease and insect and eco-friendly cultivation.

‘Manbaek’ is a bacterial blight resistant mid-late maturing rice cultivar with high grain quality. ‘Manbeak’ was derived from anther culture using the backcross combination, Hopum*2/SR30075. ‘Hopum’ is a mid-late maturing rice cultivar with high grain quality and ‘SR30075’ is a pyramid line carrying three bacterial blight resistance genes. ‘Manbaek’ was selected through the pedigree method, yield trials, and local adaptability tests. ‘Manbeak’ carrying two bacterial blight resistance gene Xa3 and xa5 showed high-level and broad-spectrum resistance against bacterial blight. ‘Manbaek’ was resistant to K3a, mostly virulent race in Korea, and exhibited resistance reaction against 16 Korean bacterial blight isolates. ‘Manbaek’ was a mid-late maturing rice. The heading date of ‘Manbaek’ was August 19th, which was 5 days later than that of ‘Nampyeong’. Manbaek’ was a lodging-tolerant rice with short culm and dark green leaf. Due to the low viviparous germination, ‘Manbaek’ could be a useful material to prevent pre-harvest sprouting. ‘Mabeak’ was resistant to bacterial blight and rice stripe virus, but susceptible to other virus diseases and insect pests. The yield of ‘Manbaek’ was similar to ‘Nampyeong’. ‘Manbaek’ showed excellent grain appearance and good tastes of cooked rice, so that it could contribute to improving the quality of bacterial blight resistant cultivars. ‘Manbaek’, bacterial blight resistant cultivar with high grain quality, is suitable for the cultivation at bacterial blight prone area and has been utilized in the breeding programs for enhancing the resistance against bacterial blight (Registration No. 6069).

‘Chindeul’, a new japonica rice cultivar developed from a cross between HR22538-GHB-36-4 having brown planthopper (BPH) resistance and Iksan471 having a good eating-quality and high yield, was developed by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2012. This variety has about 124 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It has 83 cm culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows resistance to bacterial blight pathogen races from K1 to K3, stripe virus and brown planthopper. The milled rice of ‘Chindeul’ exhibits translucent, relatively clear non-glutinous endosperm and medium short grain. It has lower protein content of 5.9% and good palatability of cooked rice compared with Nampyeongbyeo. The milled rice yield performance of this variety is about 5.61 MT/ha in local adaptability test for three years. ‘Chindeul’ would be useful genetic resources for multi-resistance breeding program against disease and insect.

‘Huimangchan’ is a new japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2011. This variety was derived from the three-way cross of ‘Milyang165’, ‘Shindongjin’ and ‘YR19105-Acp222’. This variety has about 126 days of growth duration from transplanting to harvesting in Honam and Youngnam plain of Korea. It is about 91 cm in culm length and tolerance to lodging. In reaction to biotic stresses, it shows moderate resistance to blast, resistance to bacterial blight pathogen races from K1 to K3, and rice stripe virus, but susceptible to other major diseases and insect pests. The milled rice of ‘Huimangchan’ has high quality, midium short grain. The milled rice yield of this variety is about 6.18 T/ha in local adaptability test for three years. ‘Huymangchan’ would be adaptable to Middle plain, Honam plain and Youngnam plain area of Korea.

‘Sanhomi’, a new japonica rice cultivar developed from a cross between Sangmibyeo and F₁ plant derived from the cross between Sangju24 and Hwayeongbyeo having bacterial blight and rice stripe virus resistance was developed by the rice breeding team of Sangju Substation, NICS, RDA in 2012. This variety has about 114 days of growth duration from transplanting to harvesting in southern mid-mountainous area of South Korea. It has 70 cm culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows multiple resistance to blast, bacterial blight and rice stripe virus. The milled rice of ‘Sanhomi’ exhibits translucent and, relatively clear non-glutinous endosperm, and medium short grain. This variety has a higher milled rice recovery (67.3%), better palatability of cooked rice and similar amylose content (19.9%) compared with Odaebyeo. The milled rice yield performance of this variety was about 5.60 MT/ha in local adaptability test for three years. ‘Sanhomi’ would be adaptable to southern mid-mountainous of South Korea.

This study was conducted to develop breeding lines carrying bacterial blight resistance genes, Xa2, Xa3, xa5, and Xa21 for enhancing the resistance of early maturing glutinous japonica rice. Resistant lines were developed by backcrossing into early maturing glutinous elite cultivar, Sangjuchalbyeo and phenotypic selection for bacterial blight resistance and agronomic traits. Selected lines were confirmed the incorporation of the resistance genes using DNA markers and evaluated the resistance reaction against four Korean and eleven Philippine bacterial bight races. HR24465 line carrying Xa2 was resistant to Korean races K1, K2, and Philippine race 9a. HR24666 line carrying Xa3 was moderately resistant or resistant to races except for Korean race K3a and Philippine race 6. Resistant lines carrying xa5 were resistant to all races except for Philippine race 6. HR24669 line carrying Xa21 was moderately resistant or resistant to races except for Korean race K1 and Philippine race 10. Yield-related traits of breeding lines exhibited similar characteristics to Sangjuchalbyeo. These resistant lines could be useful breeding materials for improving the resistance of early maturing glutinous japonica rice against Xanthomonas oryzae pv. oryzae.