“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).

‘Dahongmi’ was developed to enhance the quality of colored rice by crossing ‘Jeogjinju’, Korea’s red-brown colored rice variety, with ‘Junam’, a variety known for excellent cultivation characteristics. ‘Dahongmi’ is a mid-maturing cultivar harvested approximately 15 days later than ‘Jeogjinju’, suitable for the mid-central plains. Each ‘Dahongmi’ plant bears 14 panicles, similar to that in ‘Jeogjinju’ but with an additional 22 grains per panicle and a heavier 1000-grain weight compared to that of ‘Jeogjinju’. ‘Dahongmi’ exhibited superior low-temperature germination rate (85.1%) and a higher percentage of fertile grains at a cold-water irrigated nursery (36.2%) compared to ‘Jeogjinju’. The stem height of ‘Dahongmi’ is 89.7 cm, similar to that of ‘Jeogjinju’. However, ‘Dahongmi’ has a third node height 9 cm shorter than that of ‘Jeogjinju’, enhancing its resistance to lodging. Furthermore, it displayed resistance to leaf blast, bacterial leaf blight (K1, K2, and K3 strains), and rice stripe virus, ensuring stability during cultivation. The protein and amylose content of ‘Dahongmi’ are 5.5% and 18.9%, respectively, similar to that of ‘Jeogjinju’ (5.9%, 18.3%). The levels of antioxidant components such as total polyphenols and flavonoids are comparable to that of ‘Jeogjinju’. However, ‘Dahongmi’ does not exhibit resistance against bacterial leaf blight strain K3a and delphacidae, underscoring the importance of timely and balanced fertilization for effective early-stage management. ‘Dahongmi’ exhibits better yield, straw strength, and plant architecture compared to ‘Jeogjinju’. It has immense potential for augmenting the yield of high-antioxidant-pigmented rice varieties. In addition, it could provide valuable foundational data for the brown rice processing industry (Registration Number: 8680).

‘Gowoo’, a mid-late flowering, high yielding rice (Oryza sativa L.) cultivar with glabrous leaf and hull and resistant to multiple diseases and insects, was developed for forage use. It was developed for use as a whole crop silage obtained from a cross between ‘Kusahonami’ with high biomass, smooth leaf and hull, lodging resistance and Japonica high yielding line ‘Iksan514,’ which showed resistance to bacterial blight (BB) (race K1, K2, K3) and rice stripe virus (RSV). In the central plain region of Suwon, ‘Gowoo’ cultivar exhibited a growth period of approximately 120 days from seeding to heading, 111 cm culm length, 22 cm panicle length, 12 panicles per hill, 140 spikelets per panicle, and 1,000-grain weight of 23.4 g as brown rice. This hairless forage rice variety was weak in response to cold stresses, similar to ‘Nokyang’. However, it was resistant to lodging in the field and showed a strong response to viviparous germination. In addition, ‘Gowoo’ was resistant to leaf and neck blast, BB, RSV, and small brown planthopper. Its average dry matter yield for three years reached 18.2 MT/ha, which was 21% higher than that of ‘Nokyang’. This glabrous cultivar had 5.3% crude protein and 68.2% total digestible nutrients, a little low compared to ‘Nokyang’. In Korea peninsular, ‘Gowoo’ grows well in central and southern plain and is good to harvest between 15 to 30 days after heading to improve its feeding value and digestion rate of livestock (Grant No. 8681).

Objective
of this study was to investigate the difference of cadmium (Cd) levels in rice grains from non-polluted fields and to define the gene associated with Cd uptake for producing safety food. Cd was analyzed by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The average concentration of Cd in rice grains was 0.943 μg/kg and Cd levels ranged from 0.050 to 5.699 μg/kg. Genome-Wide Association study (GWAS) based on phenotype data for Cd levels was performed. However, results of GWAS were affected by subpopulation structure and caused false positive. Therefore, GWAS for rice ecotypes (temperate Japonica, tropical Japonica, Indica, Aus, Aromatic, and Admixture) was performed to minimize false positive. GWAS results showed that Os01g0611300, Os01g0611900, Os01g0611950, Os01g0612000, Os01g0612200, Os11g0444400, Os11g0444700, Os11g0444800, and Os11g0444900 genes have significant correlation with Cd levels in rice grains. The sequences of these genes were compared to sequence positions of each other gene (haplotype analysis). According to the results of haplotype analysis, Cd levels of non-synonymous group were higher than other groups and sequence of non-synonymous group was similar to that of Indica. These results were corresponding to the previous research result that Cd levels of Indica were higher than Japonica. Therefore, candidate genes detected through GWAS need to be examined by knock-out or cross breeding.