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This study was performed to determine the optimum transplanting dates of ‘Bbareumi’ in the Chungnam Plain area. ‘Bbareumi’ was transplanted into a rice research field of Chungnam Agricultural Research and Extension Services at intervals of approximately 15 days from April 17th to August 1st in 2019 and 2020. The heading dates of ‘Bbareumi’ were June 23rd to September 2nd depending on transplanting dates. The highest milled-rice yield was 5.61 MT/ha on May 1st and the lowest was 3.65 MT/ha on August 1st. As the transplanting date was delayed, protein content increased; however, the number of days from transplanting to heading decreased. Protein content and the number of days from transplanting to heading showed a highly significant correlation (R² = 0.802**). Therefore, it was found that early transplanting was beneficial to produce lower protein content because head rice percentage was 84-87% for early (April 17th to May 16th), 74-80% normal (June 1st to June 16th), and 86-95% for the late transplanting date (July 1st to August 1st). The mean temperature during the ripening stage differed according to the transplanting dates, and early transplanting showed a lower temperature than the normal one (May 16th to June 15th) and a higher head rice percentage. Therefore, extremely early maturing rice cultivars should be transplanted between late April and early May to obtain lower protein content and higher head rice percentage. These results will be useful for rice breeding programs, as it is generally recognized that early transplanting results in poor rice quality; however, this study revealed contrasting results. [ABSTRACT FROM AUTHOR]

Rice research in Korea during the past 100 years has gone through tremendous changes and improvements as the country underwent a turbulent history of transformation. Full-scale R&D modernization began in the 1970s, when the government focused policy on achieving self-sufficiency in rice in order to establish the foundation for national economic growth. A major landmark was reached by the development of the rice variety “Tongil” and its cultivation technology, which was at the core of the unprecedented Korean “Green Revolution”. Since achieving self-sufficiency in rice, the breeding goal of Korea moved from increasing yield to improving grain quality as more consumers began to seek high quality food products in the 1980s. This change led to the establishment of the high quality rice breeding platform for enhancing the global competitiveness of Korean rice to cope with the opening of domestic rice market in the 2000s. Currently, the major breeding goals in rice are developing premium quality cultivars for table rice and specialized cultivars for boosting processed food industry. To date, the National Institute of Crop Science has released a total of 300 rice cultivars, including 202 table rice and 98 specialized usage cultivars. Diverse technologies have been developed and utilized for breeding new rice cultivars to meet changing needs. In the next 100 years of rice breeding, the convergence of traditional crop improvement technologies and the new breeding technologies utilizing recent advances in biotechnology will play a crucial role in enhancing breeding efficiency. [ABSTRACT FROM AUTHOR]

‘Yechan’ is a high grain quality mid-late maturing rice cultivar with lodging tolerance and multiple disease resistance. It was a derived from a cross between ‘Hopum’ and ‘Iksan537’ (cultivar name ‘Haepum’). ‘Hopum’ is a high grain quality mid-late maturing rice cultivar with strong lodging tolerance and ‘Haepum’ is a high grain quality medium maturing rice cultivar with multiple disease resistance. To shorten the breeding period, another culture method was applied to the F1 plants. ‘Yechan’ was selected through the pedigree method, yield trials, and local adaptability tests, with a high selection pressure for grain quality, lodging, and disease resistance. The heading date of ‘Yechan’ was August 14, one day later than that of ‘Nampyeong’. ‘Yechan’ is a cultivar tolerant to lodging and it has short culms. It has multiple disease resistance against rice blast, rice stripe virus, and bacterial blight, including the K3a race, the most virulent race in Korea. The yield of ‘Yechan’ was similar to that of ‘Nampyeong’. ‘Yechan’ showed excellent grain appearance, superior taste when cooked, and enhanced milling performance; thus, we concluded that it could contribute to the improvement of Korean japonica rice cultivar quality. ‘Yechan’, a high grain quality mid-late maturing rice cultivar with lodging tolerance and multiple disease resistance, would be suitable for cultivation in the southern plain area in Korea and has been utilized in the breeding programs aimed at enhancing the grain quality and stability for the cultivation of Korean japonica rice (Registration No. 7647). [ABSTRACT FROM AUTHOR]

‘Jinsang' is a new japonica rice variety was derived from a cross between ‘Yumetsukushi' as a high grain quality and ‘Milky queen' with low amylose content and good eating quality in 2000, and selected by pedigree breeding method until M8 generation. As a result, a promising line, JCH33M-15-1-9-1-5-1-1-1, was advanced and designated as the name of ‘HJ-2' in 2009. This variety has about 111 days to heading after sowing and has 75.2 cm culm height. Milled rice of that shows dull and medium short grain and 1,000-grain weight was about 20.9 g. It has low amylose content of 11.9% and lower protein content of 6.8%. The yield potential of ‘Jinsang' in brown rice was about 4.57 MT/ha by ordinary culture in replicated yield trial test. [ABSTRACT FROM AUTHOR]

The ‘Cheongbaekchal', a glutinous rice (Oryza sativa L.) cultivar, was developed by the rice breeding team of National Institute of Crop Science, RDA, in 2010. It was derived from a cross between SR20261-5-4-10 and ‘Jinbuchal' which is an extremely early maturing variety with northern alpine area adaptability. The heading date of ‘Cheongbaekchal' is July 27 that is 4 days earlier than that of ‘Odae’. This cultivar has 68 cm of culm length, 14 tillers per hill and 80 spikelets per panicle that is more than that of ‘Odae’. This variety showed similar cold tolerance to ‘Odae’ while exposed to cold stress. This variety showed resistance to blast disease but susceptible to bacterial blight, stripe virus and planthoppers. The milled rice of this variety exhibits opaque and glutinous endosperm and short grain shape. This variety has lower Alkali digestive value (5.5) than that of ‘Odae’. The dehulling recovery rate of ‘Cheongbaekchal' is lower than those of ‘Odae’. The milled rice yield performance of ‘Cheongbaekchal' was 5.35 MT/ha in local adaptability test for three years. ‘Cheongbaekchal' is adaptable to northern plain and mid-mountainous, southern alpine and north-eastern coastal area of Korea. [ABSTRACT FROM AUTHOR]

The ‘Jungsaenggold' is a japonica rice variety developed from a cross between Yeongdeog34 which has translucent milled rice and good milling properties and F1 of Yumetsukushi and Saesangju that the varieties have a good canopy architecture, cold tolerance and early maturing property by the rice breeding team at NICS, RDA in 2011. The heading date of this variety is August 8 and four days earlier than check variety, ‘Hwaseong'. ‘Jungsaenggold' has 78 cm of culm length and 113 spikelets per panicle. This variety showed similar cold tolerance to ‘Hwaseong' while exposed to cold stress. This variety showed resistance to blast disease and stripe virus, but susceptible to bacterial leaf blight and planthoppers. The milled rice of this variety exhibits translucent, clear non-glutinous endosperm and short grain shape. ‘Jungsaenggold' has better palatability index of cooked rice than that of ‘Hwaseong' because of lower protein content (6.2%) and amylose content (17.2%) than that of ‘Hwaseong'. The whole grain rate of milled rice is higher than that of Hwaseong and milled rice recovery rate of ‘Jungsaenggold' is similar to those of Hwaseong. ‘Jungsaenggold' has 5.05 MT/ha of milled rice productivity in ordinary cultivation and 5.51 MT/ha in early cultivation. ‘Jungsaenggold' could be adaptable to the middle plain area in Korea. [ABSTRACT FROM AUTHOR]

‘Sodami' is a new high quality japonica rice variety developed from a cross between ‘Iksan469' and ‘Unbong31' by the rice breeding team of Rice Breeding and Cultivation Research Division, Department of Rice & Winter Cereal Crop, NICS, RDA. This variety is suitable for low level nitrogen fertilizer (LNF, 6kg/10 a) cultivation at ordinary season. The heading date of ‘Sodami' was August 16th, the same that of ‘Nampyeong' at ordinary season cultivation. Culm length of ‘Sodami' was about 81 cm and this variety had 12 tillers per hill and 134 spikelets per panicle. Ripened grain rate of this variety was approximately 86.8%. The spikelet fertility of ‘Sodami' was similar to that of ‘Sobi' and higher than that of ‘Nampyeong' by 26% when exposed to cold stress. ‘Sodami' is resistant to bacterial blight and rice stripe virus but susceptible to blast disease and planthoppers. The milled rice of ‘Sodami' exhibits translucent, clear non-glutinous endosperm and medium short grain. It shows lower protein content than that of ‘Nampyeong' and ‘Sobi'. The milled rice yield of this variety was slightly higher than that of ‘Sobi' by 3% as about 5.2 MT/ha in LNF cultivation at ordinary season but it was not significantly different and much higher by 9% as about 6.0 MT/ha than that of ‘Nampyeong' in ordinary season cultivation in local adaptability test for three years. ‘Sodami' could be adaptable to plain areas of south of Chungcheongnamdo and southwest coastal district of Korea. [ABSTRACT FROM AUTHOR]

‘Suan' is a new high quality japonica rice variety developed from a cross between HR20017-B-19-3-1 and Iksan467 in 2003 by the rice breeding team of Rice Breeding and Cultivation Research Division, Department of Rice & Winter Cereal Crop, National Institute of Crop Science, RDA. in 2010. ‘Suan' has about 132 days growth duration from direct seeding to harvesting in the southern plain including Chungcheong province. The heading date of ‘Suan' is August 10, faster than that of ‘Nampyeongbyeo’ by 6 days at ordinary season cultivation. Culm length of ‘Suan' is about 79 cm and tiller number per hill is similar to ‘Nampyeongbyeo’ and spikelet number per panicle is fewer than ‘Nampyeongbyeo’. Ripened grain rate of this variety is approximately 94.6 %, higher than ‘Nampyeongbyeo’ and ‘Suan' showed higher spikelet fertility than ‘Nampyeongbyeo’ by 12 % when exposed to cold stress. ‘Suan' has medium size of brown rice and is resistant to leaf blast, bacterial blight and stripe virus disease but susceptible to insect pests. The milled kernel of ‘Suan' is translucent with non-glutinous endosperm. Protein content of ‘Suan' is about 6.5%, amylose content and palatability of cooked rice is similar to ‘Nampyeongbyeo’. The milled rice yield is about 5.47 MT/ha, 9% higher under wet-direct seeding, 5.56 MT/ha, 9% higher under dry-direct seeding than ‘Juanbyeo’ and 5.80 MT/ha, 4% higher under the standard fertilizer level of the ordinary transplanting cultivation when compared with ‘Nampyeongbyeo’. ‘Suan' would be adaptable for ordinary transplanting and direct seeding in the plain areas of south of Chungnam and southwest coastal district of Korea. [ABSTRACT FROM AUTHOR]