“Jeongdami” is a specialized rice (Oryza sativa L.) variety developed to enhance the competitiveness of regional branded rice through its distinct characteristics, setting it apart from those from other regions. It is an early-maturing, semi-dwarf variety with strong resistance to rice blast and features intermediate stickiness with a low amylose content (11.6%), using “Wolbaek” as the maternal parent. The paternal parent is an F₁ hybrid created by crossing the large-grain, intermediate-maturity glutinous rice variety “Nunbora,” which is resistant to bacterial blight (K1, K2, and K3), with “Boramchan,” a high-yield, medium-late Japonica variety that is resistant to bacterial blight (K1, K2, and K3) and stripe virus. The breeding process culminated in 2020, resulting in “Jeongdami.”. Key agricultural characteristics include an average heading date of August 15, which is 6 days earlier than “Baekjinju”, an important low amylose mid-late cultivar, making it a medium-late variety when grown in the four plains regions in the central plains of Korea. Its culm length is moderately short at 77 cm, with an average of 16 panicles per hill and 96 spikelets per panicle. The 1,000-grain weight of brown rice is 20.0 g, similar to that of “Baekjinju.” There was no premature heading, leaf senescence at maturity was moderate, and the pre-harvest germination rate was 1.7%, lower than that of “Baekjinju” (7.5%). The overall cold tolerance rating was 7, indicating weak tolerance similar to “Baekjinju;” however, the variety showed strong lodging resistance in the field. “Jeongdami” exhibited strong resistance to bacterial blight (K1, K2, and K3) and moderate resistance to leaf blast but showed susceptibility to stripe virus, brown planthopper, and white-backed planthopper. The average polished rice yield was 547 kg per 10a, a 16% increase compared to that of “Baekjinju” (472 kg). The grain shape, with a paddy grain length-to-width ratio of 2.2 and a brown rice length-to-width ratio of 1.8, was similar to that of “Baekjinju,” maintaining a short and round shape. The endosperm is clearer than that of “Baekjinju,” providing superior visual quality. The protein content was 6.2%, and the amylose content was 11.5%, indicating intermediate stickiness, which was attributed to the Wx-mq gene. Due to its soft texture and stable cultivation, “Jeongdami” will contribute to increasing rice consumption by enhancing the competitiveness of regionally branded rice with its excellent eating quality and cultivation stability. (Grant No. 9168).

The rice cultivar, ‘Dapum’, is a high-quality, late-maturing rice with low amylose content developed by the Chungcheongnam-do Agricultural Research and Extension Services (Yesan, Korea). Dapum was derived from a cross between Miho, a processed rice cultivar known for its cultivation stability and low amylose content, as the maternal parent, and Daohuaxing2, a high-quality aromatic rice cultivar, as the paternal parent. Subsequently, a pedigree breeding method was employed, and yield trials conducted from 2019-2020, followed by local adaptability tests from 2020-2021. As a result of the local adaptability test, the heading date of ‘Dapum’ was August 28^th, which is slower than the cultivars mainly cultivated in the Chungnam Province in Korea; therefore, it can be ripened at an appropriate temperature. The yield of milled ‘Dapum’ rice under standard fertilizer conditions was approximately 572 kg/10a, which was 15 kg/10a higher than that of Miho. The amylose content of ‘Dapum’ was 12.5%, similar to that of Miho, and the glossiness of cooked rice, which reflects its indirect eating quality, was 86.8, which was 7.0 points higher than that of Miho. The new rice cultivar, ‘Dapum’, is expected to be used in various ways, such as for cooked and processed rice, due to its low amylose content and good eating quality. Further, it has the potential to enhance the competitiveness of rice production in the Chungnam Province by diversifying the rice market, which has traditionally focused on mid-maturing, non-glutinous rice (Registration No. 10181).

‘Miho’ (Milyang300) was developed as a processing rice by means of pedigree selection. ‘Milyang300’ has slightly opaque seeds with low amylose content (11.2%), unlike cultivars such as Baegjinju and Milky-queen, which have seeds with low amylose but are opaque. ‘Milyang300’ was selected and named ‘Miho’ in 2016. ‘Miho’ is a late-maturing ecotype with an average heading date of August 21^st. It shows mild resistance to leaf blast and strong resistance to rice stripe virus, and bacterial blight (K1-K3); however, it is susceptible to brown plant hopper infestation. The yield capacity of ‘Miho’ determined over 3 years of regional yield trials was 565 kg/10 a. In terms of processing properties, ‘Miho’ shows no significant differences in textural properties when stored for 6-48 h at 3℃ and -18℃. Moreover, the physical properties of ‘Miho’ remain unaltered during freeze-thaw processes. Thus, the low-amylose rice ‘Miho’ may be suitable for the production of refrigerated and frozen cooked rice (Registration No. 7656).

‘Golden queen 3’, an aromatic rice variety, was developed by Seedpia inc. (Suwon, Korea) breeding company in 2014. This cultivar was derived from a cross between ‘HJ-11’, a high-yield, aromatic line, and ‘JCH33M-15-1-9-1’, which has a low amylose content. During the F₃-F₈ generation, breeding lines were selected using a pedigree breeding method. The most promising line (JS9-3-73-15-5-1-5-3-1-1) was advanced and named ‘SP005’ in 2013. This variety was headed on August 13, two days later than ‘Hwayeong’ in the ‘in middle plane’ is commonly used to distinguish rice cultivation areas in Korea, so I think it's no problem to the understanding for readers (including farmers). The culm and panicle lengths of this variety were 75.7 cm and 20.1 cm, respectively. It has approximately 14.7 tillers per hill and 104.8 spikelets per panicle, and the 1000-grain weight was 21.8 g. The yield performance was 5.47 MT/ha in the local adaptability test, and the amylose content of this variety was 12.5%. 2-Acetyl-1-pyrroline was detected as the major volatile ingredient in aromatic rice, and a 1 bp insertion on the 14th exon (badh2.7 allele) was identified in the Badh2 gene. (Registration No. 7308).

‘Gawagi1’ is an early maturing, low amylose rice variety with a medium to short culm, developed by Gyeonggi-Do Agricultural Research & Extension Services, Hwaseong, Korea in 2016. ‘Gawagi1’ was derived from the cross between ‘Baegjinju’ and ‘Sangmibyeo’ in 2004. Heading date was 4th of August 15 day earlier than ‘Baegjinju’ in Gyeonggido. The culm length was 67 cm. It had 15 panicles per hill and 104 spikelets per panicle. It is a medium-grain variety whose 1,000 grains weight of brown rice is 19.3 g. The protein content of milled rice was 6.3%, which is higher than that of ‘Baegjinju’ and its amylose content was 8.2% which is lower than that of ‘Baegjinju’. Its milling ratio is 75.5%, which is higher than that of ‘Baegjinju’. The yield of milled rice was 4.99 MT/ha under the standard cultivation practices at the local adaptability tests in 3 regions from 2014 to 2016. ‘Gawagi1’ is highly adaptable to Gyeonggido, especially to the northern region of Han River. (Registration No. 7280)

The Jinsang 2 cultivar is a new late-maturing, low amylose rice variety with a medium to short culm created by the Seedpia Inc. breeding company in 2012. This variety was derived from a cross between Junam, a high-yield and lodging tolerant source, and DM3-8-72-9, which was derived from a cross between Donjinchal and Milkyqueen, with a low amylose content and superior agronomic traits. A general single seed descent method was applied to develop Jinsang 2 in the F3-F4 generations. During the F5-F8 generations, the breeding lines were selected through a pedigree breeding method. A promising line, JS6-B-52-8-3-5-1-B-B-B, was selected and named HJ-6 in 2011. This variety headed on the 25^th of August, which was 14 days later than Hwayoung. The culm and panicle length of the variety was 71.6 cm and 19.9 cm, respectively. The milled rice from the variety had a dull and medium- to short-grain, and the 1,000-grain weight was around 20.0 g. It had a low amylose content of 12.2% and a low protein content of 6.8%. The yield performance of Jinsang 2 milled rice was about 5.36 MT/ha from the ordinary culture replicated yield trial test.

The amylose contents of rice determine eating quality which is one of the major traits in rice breeding program. To identify the low-amylose gene of the japonica rice cultivar Baegjinju, genetic analysis was conducted using 200 F₂ population derived from a cross between the japonica cultivars, Saeilmi and Baegjinju. Individual F₂ plants were classified as wild type (translucent grain) and mutant type (dull grain) based on the grain appearance of brown rice. Two hundred F₂ plants were segregated into 155 wild type plants and 45 mutant type plants, which fit the 3:1 ratio (x² = 0.667, df = 1, p = 0.414) and this result indicated the low-amylose gene of Baegjinju is a single recessive gene which controls the amylose contents. Linkage analysis was conducted to localize the low-amylose gene of Baegjinju and fine mapped within an 800-kb interval between 17.5 to 18.8Mb on short arm of chromosome 10. Co-segregated SSR marker, RM25648 was developed and it could be useful for marker-assisted selection and determination of the genetic resource related with amylose contents in rice breeding.

In chronic renal failure, to reduce the burden on the kidneys, it is necessary to provide patients with therapy based on a low-protein diet. To cope with this situation, low and easy to-digest protein rice variety is helpful. ‘Geongyang2’, low glutelins rice cultivar, was developed by the National Institute of Crop Science (NICS), RDA, Miryang, Korea in 2012. ‘Geongyang2’was derived from a cross between ‘Junambyeo’and‘Chugoku 173’ as a source of low glutelin and amylose. The pedigree of ‘Geongyang2’was YR24174-B-B-B-B-46 and designated as the ‘Milyang262’ in 2009. The local adaptability test of ‘Milyang262’ was carried out at six locations from 2010 to 2012. ‘Geongyang2’ is a mid-maturing ecotype with 65cm in culm length and the number of spikelet/panicle and 1,000 grain weight of brown rice were slightly lower compared to those of ‘Nampyeongbyeo’. ‘Geongyang2’ is resistant to bacterial blight and virus disease while susceptible to major insect and pest. The glutelin and amylose contents of ‘Geongyang2’ were 63.1% and 11.5%, respectively. The milled rice yield of ‘Gyeongyang2’ is 4.61MT/ha at the ordinary transplanting of the local adaptability test. This cultivar would be adaptable to the plain paddy field of middle, honam and yeongnam province of Korea under ordinary cropping system.

‘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.