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For the purpose of breeding documentation, researchers and breeders kept handwritten records of the breeding history, including parental information and breeding methods. The cultivars were used again as parents for further breeding, and modern cultivars of rice have a wide range of alleles from many generations of parents and ancestors. To understand such a breeding history, it is necessary to ask around for relevant information, which is then usually documented in Excel or Word by multiple breeders or breeding institutes. Here, we constructed RicePedigree, which contains the breeding history of rice based on the documents provided by the Rural Development Administration (RDA) in Korea. We devised a simple method for collecting a breeding history and storing it in a database. RicePedigree is a web-based application on the database that facilitates researchers' and breeders' utilization of the breeding history of rice. Based on the query cultivar name, it will return a hierarchical tree of breeding histories and a list of cultivars and breeding lines that contain query cultivars in their breeding histories. This app would be a good way to review and keep track of information about current and future cultivars. [ABSTRACT FROM AUTHOR]

‘Haedeul’ is a high-quality rice variety with early maturing that adapts to the central region of Korea. This cultivar was crossed between ‘Gopum’, which has excellent taste, and ‘Hoban’, which has a low viviparous germination rate and is moderately tolerant of cold, by the rice breeding team of the Department of Central Area Crop Science, NlCS, RDA, in 2017. In early-transplanting cultivation, the heading date of ‘Haedeul’ was July 24 in central area of Korea, which was seven days later than that of ‘Jopyeong’. ‘Haedeul’ had a culm length of 75 cm and 99 spikelets per panicle. The viviparous germination rate of ‘Haedeul’ was 7.7%. It showed resistance to blast and bacterial blight (K1, K2, K3 race), but was susceptible to the K3a race of bacterial blight, stripe virus, dwarf and black streak dwarf viruses, and plant-hoppers. The milled rice of this variety exhibited a translucent and medium short grain shape. The cooked rice grains of ‘Haedeul’ had an excellent palatability index (0.61) and lower amylose content (18.0%) than that of ‘Jopyeong’. The grain milling characteristics were better than those of ‘Jopyeong’, especially the head rice milling recovery ratio and head rice ratio (94.9%). ‘Haedeul’ milled rice productivity averaged 5.32 MT/ha at five sites under ordinary cultivation. [ABSTRACT FROM AUTHOR]

Rice blast is one of the most serious agricultural diseases in the world. Rice blast can be managed using low nitrogen fertilizers, treatment with chemical fungicides, and the most effective resistant varieties. Many genetic resources have been investigated and used along with molecular markers to breed blast-resistant rice varieties. In this study, the genetic diversity of blast resistance genes using 27 functional/linked markers and rice blast incidence over three years was investigated in 296 Korean rice varieties. Blast incidence was determined using a 0-9 scoring system (0=no lesions to 9=dead leaves) in nursery tests. The blast incidence of 296 rice varieties showed a significant correlation between years (r>0.64, p<0.001). The 261 Japonica varieties showed blast resistance compared to 114 mid-late maturing varieties or 96 medium-maturing varieties. 35 Tongil-type varieties also exhibited greater resistance than Japonica varieties. DNA marker-trait association analysis was conducted using 27 DNA markers linked to 19 blast resistance genes. Twelve DNA markers showed significant associations with the average blast incidence over 3 years. The ‘9871.T7E’ marker linked with Pi40 was strongly associated with blast disease, with a phenotypic variance of 24% over 3 years (p<0.001). Among the varieties harboring the Pi40 allele, early maturing varieties accounted for 87%. These results imply that the blast resistance of early maturing Korean varieties is associated with the Pi40 gene. These results will be beneficial for breeding blast-resistant rice in Korea. [ABSTRACT FROM AUTHOR]

Temperate japonica is used as the parent for crossing in the breeding of new rice cultivars in Korea, and the grain shape of the developed lines or cultivars is a semi-round and medium-short grain length. To overcome the current low quantity of japonica cultivar germplasm and deterioration in quality caused by climate change, it is necessary to diversify the grain characteristics of japonica. Most of the United States (US) cultivars are classified as medium, long, extra-long, and half spindle- and spindle-shaped grains. The qSW5 allelotype, a major gene involved in grain width, is found in all US cultivars. In addition, the US cultivar ‘Saber’ has both qgl3 and GS3_B alleles, which have low allele frequencies among Korean rice cultivars, and ‘A020’ had gw8, an allele with a reduced grain width. The pasting properties and texture of medium-grain length and half-spindle-shaped cultivars were relatively similar to those of the Korean rice cultivar, but different from those of long-grain and long spindle-shaped cultivars. Therefore, grain shape is associated with pasting properties and texture traits. Among the rice cultivars in the US, tropical japonica belongs to the same japonica as the Korean rice cultivar; however, its grain shape is similar to that of indica. As grain shape is also related to grain quality, US cultivars can be used as a useful genetic resource for diversifying the grain characteristics of Korean japonica cultivars and breeding new cultivars. [ABSTRACT FROM AUTHOR]

Revealing genomic variation of representative and diverse germplasm is the cornerstone of deploying genomics information into genetic improvement programs of species of agricultural importance. Here we report the re-sequencing of 239 japonica rice elites representing the genetic diversity of japonica germplasm in China, Japan and Korea. A total of 4.8 million SNPs and PAV of 35,634 genes were identified. The elites from Japan and Korea are closely related and relatively less diverse than those from China. A japonica rice pan-genome was constructed, and 35 Mb non-redundant novel sequences were identified, from which 1131 novel genes were predicted. Strong selection signals of genomic regions were detected on most of the chromosomes. The heading date genes Hd1 and Hd3a have been artificially selected during the breeding process. The results from this study lay the foundation for future whole genome sequences-enabled breeding in rice and provide a paradigm for other species. • A set of 239 diverse japonica rice elites was re-sequenced, and 4.8 million SNPs and PAV of 35,634 genes were identified. • The elites from Japan and Korea are closely related and relatively less diverse than those from Northeast China. • A japonica rice pan-genome was constructed, and 1131 full-length novel genes were predicted from 35 Mb non-redundant novel sequences. • Strong selection signals of genomic regions were detected on most of the chromosomes. [ABSTRACT FROM AUTHOR]

Rice is the most important staple food in Korea. Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases in the rice-growing world and in Korea. Eighteen major blast resistance genes were screened in 33 leading Korean japonica varieties using 44 DNA markers. The 33 leading japonica varieties are cultivated in 659,642 ha (90.4%), and a variety of Samkwang is cultivated widely on a nation-wide scale. Four resistance genes, Pia, Pib, Pi19, and Pb1, were detected in 10-21 varieties, and the R-genes of Pii, Pish, Pita/Pita-2, Piz/Piz-t, Pi35, and Pi65(t), were present in 2-5 varieties. Five R-genes, Pit, Pi5, Pi9, pi21, and Pi40, were not detected in the Korean japonica rice varieties. A total of six varieties, two mid-late flowering varieties, Ilmi and Saeilmi, a medium flowering variety Gopum; and three early flowering varieties Jopyeong, Haedamssal, and Haedeul; were resistant to blast nursery screening over 12 years. A variety of Gopum harbored alleles for Piz/Piz-t, and three early flowering varieties, Jopyeong, Haedamssal, and Haedeul, had extensive loci of the multiple-gene family Piz/Piz-t, Pi9, and Pi40 on chromosome 6. Two mid-late flowering varieties, Ilmi and Saeilmi, harbored the Pita-2 gene, and Gopum had Pita. In the japonica rice breeding program, an effective means for enhancing stable resistance to blast would be introduced to 2-3 R genes among resistance genes Pit, Pi5, Pi9, pi21 and Pi40 which were not identified in Korean japonica rice varieties, and resistance genes Pita/Pita-2, Piz-t/Piz-5, to 2-3 R genes among and Pi20 that showed stable resistance in monogenic IRBL lines. [ABSTRACT FROM AUTHOR]

‘Sangbo’ is a japonica rice (Oryza sativa L.) variety with high head rice grain ratio and good ripened grain color, as well as resistance to rice dwarf virus (RDV) and bacterial blight disease (BB). It was developed by the rice breeding team of the Yeongdeok Branch of the National Institute of Crop Science, RDA, Korea, in 2015. This variety was derived in the 2002 summer season from a cross between ‘Yeongdeog32’, with high eating quality, and ‘Nampyeong’, with a high milling ratio. In 2012, a promising line, YR24256-142-5-3-1-1-2, selected by the pedigree breeding method, was designated the name, ‘Yeongdeog59’. After performing a local adaptability test at nine locations from 2013 to 2015, ‘Yeongdeog59’ was released with the name ‘Sangbo’ in 2015. ‘Sangbo’ has a culm length of 77 cm and a medium-late growth duration. This variety was resistant to K1, K2, and K3 races of bacterial blight, along with the dwarf virus, and was moderately resistant to leaf blast disease. Based on the results of a panel test, ‘Sangbo’ has translucent and clear milled rice kernel without white core and belly rice, and good eating quality. The yield potential of ‘Sangbo’ in milled rice was approximately 6.21 MT/ha at the ordinary fertilizer level of the local adaptability test (LAT). This cultivar would be adaptable to the middle plain, south plain, Yeongnam plain, east coastal area, and south mid-mountainous areas of Korea. [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]

Jungmo1022’, a japonica rice cultivar, was developed by a cross between ‘Jinbu31’ (IT212616) and ‘Gyodong23’ (IT213764) by the rice breeding team at the National Institute of Crop Science, Korea, in 2000. ‘Jinbu31’ is tolerant to cold, and ‘Gyodong23’ is early maturing with high yield potential. The growth period of ‘Jungmo1022’ in paddy fields was 116 days on the North-middle highland in Korea, shorter than that of ‘Jinbu’. The culm length of ‘Jungmo1022’ was 67 cm, which was 2 cm shorter than that of ‘Jinbu’. There were 91 spikelets per panicle in ‘Jungmo1022’. The elite line was developed by shuttle breeding in a cold screening field at Chuncheon and highland Jinbu sites in order to screen for cold tolerant varieties. Forty-five lines with more than 50% fertility were selected from the F2 generation in the cold screening field, and the line SR28990-B-2-2-2 was selected by the pedigree breeding method through F3-F7 generations cultivated on the North-middle highland in Jinbu. During the yield trial conducted in 2008-2009 yield trial, an early heading, high-yielding, and cold tolerant line ‘Jinbu 48’ was selected for the local adaptability tests conducted from 2010 to 2012. The early maturing and cold-tolerant ‘Jinbu 48’ was superior to ‘Jinbu’ in exhibiting shorter heading delay, reduced culm length, and spikelet fertility under cold temperature. The new line showed a milled rice productivity of 5.69 MT/ha at Jinbu sites under North-middle highland cultivation and was registered as a new cultivar ‘Jungmo1022’ (Registration No. 5563). [ABSTRACT FROM AUTHOR]

Direct seeding is increasingly being practiced in rice cultivation areas because it saves labour and reduces cost of production and management. In this study, four japonica‐type breeding lines were developed from a cross of a japonica cultivar and an AG‐tolerant donor, KHO, using marker‐assisted selection. Validation of the target genes AG1 and AG2 in the selected lines was examined by PCR analysis and the background recovery rate by the recurrent parent was confirmed by genotyping using a 6K SNP chip. Compared to the recurrent, the survival rates of the selected lines were improved in a range from 33% to 115% in three conditions; in particular, the survival rate was increased in more than twice that of the recurrent parent under the hypoxic condition. The main agronomic trait, yield and quality‐related traits were similar to those of the recurrent parent. The use of these lines will contribute to the expansion of the cultivation area due to the proven economic benefits of direct seeding in Korea. [ABSTRACT FROM AUTHOR]

‘Jinhan’, a japonica rice variety, was developed from a cross between ‘Cheolwon68’ (IT218244) and ‘Junghwabyeo’ (IT260473) by the rice breeding team at National Institute of Crop Science in 2015. ‘Cheolwon68’ is early maturing and resistant to blast disease, and ‘Junghwabyeo’ is a cold-tolerant and high-quality variety. The growth duration of ‘Jinhan’ in the paddy field was 116 days in the Northern Central Highland in Korea, which was similar to that of ‘Jinbu’. The culm length of ‘Jinhan’ was 61 cm, which was 10 cm shorter than that of ‘Jinbu’. The panicle of ‘Jinhan’ was composed of 66 spikelets. The viviparous germination rate of ‘Jinhan’ was 33.2%. ‘Jinhan’ showed resistance to blast disease, but was susceptible to stripe virus, dwarf and black-streaked dwarf viruses, and plant hoppers. The milled rice grains of ‘Jinhan’ showed an excellent palatability index (0.23) and lower protein content (5.7%) than that of ‘Jinbu’. The grain milling characteristics of ‘Jinhan’ were similar to those of ‘Jinbu’. ‘Jinhan’ showed a milled rice productivity of 5.43 MT/ha at four sites cultivated in the Northern Central Highland (Registration No. 7318). [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]

Oryza sativa ‘Sinbo’ is a cultivar of japonica rice with good eating quality as well as resistance to rice dwarf virus (RDV) and bacterial blight disease (BB). It was developed in 2013 by the rice breeding team of Yeongdeok Branch, National Institute of Crop Science, RDA, Korea. This cultivar was derived from a cross between ‘Yeongdeog34‘, a cultivar with good eating quality, and ‘Saekyehwa’, a cultivar of a good plant type, in summer of 2002. A promising line (YR24264-25-3-2) selected using the pedigree breeding method was designated as ‘Yeongdeog55’ in 2010. After carrying out the local adaptability test at nine locations from 2011 to 2013, ‘Yeongdeog55’ was published under the name of ‘Sinbo’ in 2013. ‘Sinbo’ is a medium-late maturing cultivar with a short culm length of 70 cm. This cultivar is resistant to K1, K2, and K3 races of bacterial blight as well as to dwarf virus, and it is moderately resistant to leaf blast disease. The results of the panel test indicated that ‘Sinbo’ has translucent and clear milled rice kernel without white core and belly rice as well as good eating quality. The yield potential of ‘Sinbo’ was approximately 5.67 MT/ha at the ordinary fertilizer level in the local adaptability test (LAT). This cultivar could be adaptable to the middle plain, south plain, Yeongnam plain, east costal area, and south mid-mountainous area of South Korea. (Registration No. 5643) [ABSTRACT FROM AUTHOR]

‘Chamdream’ is a medium-late maturing, high-quality rice cultivar developed in 2014 by the crop breeding team of Crop Research Division, GARES, Hwaseong, Korea, in cooperation with the rice breeding team of the National Institute of Crop Science, RDA, Korea. ‘Chamdream’ was first developed in 2004 from a backcross between the F1 hybrid ‘Samgwang/Jojeongdo’ and ‘Samgwang’ cultivar. The heading date of this cultivar is August 17 th in Gyeonggido Province. Its culm length is 79 cm and it has 15 panicles per hill and 115 spikelets per panicle. It is a medium-grain brown rice cultivar with a weight of 22.9 g per 1,000 grains. Its cold tolerance is lower than that of ‘Hwaseongbyeo’ and its degree of lodging tolerance is similar to that of ‘Hwaseongbyeo’. This cultivar is resistant to bacterial leaf blight and stripe virus diseases and moderately resistant to rice blast diseases, but it is susceptible to other virus diseases and pests. The appearance of milled ‘Chamdream’ rice is clear and its protein content is 5.4%, which is lower than that of ‘Hwaseongbyeo’. The palatability of cooked ‘Chamdream’ rice is better than that of ‘Chucheongbyeo’ which is mainly cultivated in Gyeonggido. Its milling ratio is 76.8% which is higher than that of ‘Hwaseongbyeo’. The yield of milled ‘Chamdream’ rice was 5.9 MT/ha in the local adaptability tests in standard cultivation in four regions from 2012 to 2014. ‘Chamdream’ is highly adaptable to the environmental conditions of Gyeonggido Province, especially to the southern region of Han River. (Registration No. 6065) [ABSTRACT FROM AUTHOR]

The ‘Hangaru’ is a rice variety derived from a cross between ‘Seolgaeng’, which is suitable for making rice wine, and ‘Daeripbyeo1’, which has a heavy grain weight (34.8g) and is suitable for deep fried rice, by the rice breeding team at the National Institute of Crop Science, Rural Development Administration, in 2017. The heading date of ‘Hangaru’ was August 18 and was 10 days later than check variety, ‘Hwaseong’, in Suwon. It had a culm length of 79 cm and 102 spikelets per panicle, and showed similar tolerance to ‘Hwaseong’ when exposed to cold stress. ‘Hangaru’ showed medium resistance to blast disease, but susceptibility to bacterial blight, viruses and brown planthoppers. The milled rice of this variety exhibited an opaque and non-glutinous endosperm. The 1,000 grain weight of brown rice was 32.9 g, which was 10.8 g heavier than that of ‘Hwaseong’; the protein content was 7.0% and the amylose content (19.2%) was similar to that of ‘Hwaseong’. The milled rice recovery rate was lower than that of ‘Hwaseong’. However, opaque grain percentage of milled rice was 88.1%. The hardness of the rice grain was soft and the starch granule shape in the endosperm was round, similar to wheat. The average size of rice flour was 71.0 μm and the damaged starch rate was 6.4%. These results showed that this variety could be suitable for dry milling rice flour production. ‘Hangaru’ had a yield of 5.42 MT/ha of milled rice productivity in ordinary cultivation, which was 99% of that of ‘Hwaseong’. ‘Hangaru’ was adaptable to the middle plain area and Mid-west coast of Korea (Registration No. 7270). [ABSTRACT FROM AUTHOR]

‘Jungmo1033’, a japonica rice variety, was developed by the rice breeding team at the National Institute of Crop Science (NICS) in 1992. It is derived from a cross between a native variety ‘Jagwangdo’, which has translucent milled rice and medium maturity; and ‘Hwayeong’, which is an elite line with bacterial blight resistance and mid-late maturity. The heading date of ‘Jungmo1033’ was August 10 in the middle plain area of Korea, which was two days later than that of ‘Hwaseong’. ‘Jungmo1033’ has a culm length of 79 cm, which was 5 cm shorter than that of ‘Hwaseong’, and 105 spikelets per panicle. ‘Jungmo1033’ showed resistance to bacterial blight (K1, K2, and K3 races) and stripe virus, but susceptibility to the K3a race of bacterial blight, dwarf and black-streaked dwarf viruses, and planthoppers. The milled rice of this variety exhibited translucency and a medium short grain shape. It had an excellent appearance and lower amylose content (19.1%) than that of ‘Hwaseong’. The characteristics related to grain milling were better than those of ‘Hwaseong’, especially head rice milling recovery ratio and head rice ratio (94.8%). ‘Jungmo1033’ showed a milled rice productivity of 5.38 MT/ha at 11 sites under ordinary cultivation conditions. (Registration No. 5723) [ABSTRACT FROM AUTHOR]

‘Jinkwang’, a japonica rice variety, was developed by a cross between ‘Hopum’ (IT23527) and the F1 hybrid of ‘Unkwang’ (IT217814) and ‘Koshihikari’ (IT157335) by the rice breeding team at NICS in 2016. ‘Unkwang’ shows an early maturity and high yield and ‘Koshihikari’ is a high-quality variety. The growth duration of ‘Jinkwang’ in the paddy field was 114 days in the middle plain region in Korea, which was six days later than that of ‘Jopyeong’. The culm length of ‘Jinkwang’ was 62 cm, which was 13 cm shorter than that of ‘Jopyeong’. The panicle of ‘Jinkwang’ was composed of 100 spikelets. The viviparous germination rate of ‘Jinkwang’ was 28.3%. ‘Jinkwang’ showed resistance to blast and bacterial blight (K1, K2, and K3 races); however, it was susceptible to stripe virus, dwarf and black-streaked dwarf viruses, and plant hoppers. The milled rice grains of ‘Jinkwang’ showed an excellent palatability index (0.42) and lower protein content (6.2%) than that of ‘Jopyeong’. The grain milling characteristics were better than those of ‘Jopyeong’, especially in terms of brown/rough rice ratio and milled/rough rice ratio (75.9%). ‘Jinkwang’ showed a milled rice productivity of 5.91 MT/ha at eight sites under ordinary cultivation conditions. (Registration No. 7318). [ABSTRACT FROM AUTHOR]