• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.31-31
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• 2022

Rice contains a wealth of genetic diversity, both within Oryza sativa and in related A-genome species. Decades of genetic research into this diversity have identified dozens of major genes contributing to a wide variety of important traits, including disease resistance, abiotic stress tolerance (drought, salinity, submergence, heat, cold etc.), grain quality, flowering date and maturity and plant architecture. Yet despite these opportunities, very few of the major genes and QTLs known have been successfully applied through rice breeding programs to produce sustained changes in farmer's fields. This presentation will briefly examine some of the factors limiting application of major genes in the mainstream breeding programs, and steps that have been taken to alleviate those limitations. As a result of these interventions, dozens of major genes that were previously unavailable to breeders are now being used confidently in the variety development process. Case studies will be discussed of genes critical for blast resistance worldwide, rice yellow mottle virus for Africa, and new validated QTLs for salinity tolerance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.112-116
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• 1999

Genetic diversity of 31 rice varieties including 25 japonica and 6 indica varieties was evaluated using a combination of 19 microsatellite or simple sequence repeats (SSRs) and 28 random decamer oligonucle-otide primers. All 19 microsatellite primer sets representing 19 loci in the rice genome showed polymorphisms among the 31 varieties and revealed 91 alleles with an average of 4.80 bands per primer. Also all 28 random decamer primers used were informative and generated 114 non-redundant bands with a mean of 4.07 bands. Microsatellite markers detected higher number of alleles than random primers .although the mean difference was not statistically significant. A cluster analysis based on Nei＇s genetic distances calculated from the 205 bands resolved the 31 varieties into two major groups that correspond to indica and japonica subspecies, which is consistent with the genealogical information. As few as six random decamer primers or a combination of one microsatellite and four random decamer primers were sufficient to uniquely differentiate all 31 varieties. These combinations would be potentially useful in rice variety protection and identification considering that 25 out of 31 varieties used in this study are japonica rices with high grain quality and have close make up.

• Journal of Plant Biotechnology
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• v.44 no.3
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• pp.243-263
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• 2017

This study is to establish the varietal discrimination based on DNA profiling of different varieties of rice. We examined the genetic distance among Korean rice varieties using allele frequencies and a genetic diversity analysis with Simple Sequence Repeats (SSRs) markers. The analysis of the genetic diversity and genetic relationships of 243 Korean rice varieties was varied out using 20 SSRs markers. A total of 268 alleles were detected, ranging from 6 to 32, with an average of 13.45 alleles per locus, and and average of gene diversity (GD) of 0.556. Seven SSR markers were selected as key markers for discrimination among the Korean rice varieties. Concerning the results, 243 varieties (100%) were discriminated among by using acrylamide gel and fragment analyzer-based markers. In conclusion, this study provides useful basic data that can be utilized concerning Korean rice varieties breeding and development. In addition, we will have to manage and conserve as a valuable genetic resource, without losing the diversity of Korean rice varieties.

• Journal of Life Science
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• v.16 no.6
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• pp.1001-1005
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• 2006

The objective of this study was carried out to evaluate the suitability of simple sequence repeat (SSR) markers for genetic diversity assessment and identification of rice varieties. The 23 primers selected from 50 SSR primers showed polymorphisms in the 21 rice varieties. The 2 to 9 SSR alleles were detected for each locus with an average of 3.00 alleles per locus. The polymorphism information content (PIC) ranged form 0.091 to 0.839. Based on band patterns, UPGMA cluster analysis was conducted. These varieties were separate into 4 groups corresponding to rice ecotype and pedigree information and genetic distance of cluster ranging from 0.59 to 0.92. The 4 SSR primer sets (RM206, RM225, RM418, RM478) selected form 23 polymorphic primers were differentiated all the rice variety from each other by markers genotypes. These markers may be used wide range of practical application in variety identification of rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.266-266
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• 2022

The outbreaks of blast, bacterial blight and viral diseases have been increasing in early maturing rice cultivating areas in the central northern regions, recently. As the occurrence of sudden insects pests and disasters increases due to global climate warming, it is urgent to develop a variety of disaster-tolerant, high-quality varieties in response. This study was carried out to elucidate the characteristics of early-maturing, high-quality and multiple disease resistant rice variety, Cheolweon109 that was adapted to cultivation in the mid-mountainous regions of the central northern regions. Cheolweon109 was derived from a cross between Suweon546, medium maturing variety, and Sangju44 which is early maturing and resistant to blast, bacterial blight and rice stripe virus. The heading date of Cheolweon109 was July 30, 3 days later than Odae. The culm length of Cheolweon109 was 79 cm, which was about 5 cm taller than Odae, and the ripening ratio was 85.1%, which was 10% higher than that of Odae. This variety had 5.54 MT/ha of milled rice productivity, which was 99% of the Odae. Although Cheolweon109 was tall, it was strong against lodging. It was strong against bacterial blight (K1, K2, K3 race), rice stripe virus, and the pre-harvest sprouting which rate was 2.4%. The appearance of the grains of rice was clean, the glossiness was 70.6, and the head rice ratio was 95.3% high. Because Cheolweon109 had superior disease resistance, disaster resistance, and high quality than Odae, it was expected that can be used to expand the diversity of early maturing and high-quality rice varieties in central northern regions.

• Korean Journal of Community Nutrition
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• v.8 no.1
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• pp.41-52
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• 2003

The purpose of this study was to evaluate the diversity of food intake among Korean college students of a nutrition education course through the internet. Subjects were 796 nation-wide college students (male 278, female 518). A dietary survey collected from 3 day-recalls were analyzed by the Computer Aided Nutritional Analysis Program. Diet variety was assessed by DDS (dietary diversity score), MBS (meal balance score), and DVS (dietary variety score). The foods consumed in largest amounts were rice (54.42 g), citrus fruit (36.41 g) and milk (30.91 g). The foods consumed most frequently were rice (65.28%), garlic (63.65%) and salt (63.64%). The average food intake was 1325.3 g (male 1420.6 g, female 1274.1 g), with vegetable and animal food comprising 78.5% and 21.5% of total food intake, respectively. The consumption of the major five food groups comprised DDS, and 66.0% (male 56.1%, female 71.3%) of subjects had a DDS of 5 and 27.4% (male 33.5%, female 24.1%) of subjects had a DDS of 4..Groups most frequently missed were dairy products (56.5%) and fruits (41.6%). The average of MBS were 10.88 (11.61 in Seoul, 11.03 in Kyungsang, 10.88 in Chungcheong, 10.85 in Incheon, 10.57 in Kyunggi) in male and 11.08 (11.47 in Kyungsang, 11.20 in Seoul, 11.18 in Kyunggi, 10.82 in Chungcheong, 10.64 in Incheon) in female. Male students in Seoul (18.2) and female students in Kyungsang (18.6) had the greater number of consumed food items. Subjects who had higher DDS had significantly higher DVS (p < 0.001). Based on these results, the food intake of the subjects regarded as not adequate, especially with regards to the dairy and fruit groups. Considering their nutritional characteristics, dietary guidelines as well as education should be made to improve the food intake and include various foods in their diet.

• Journal of the Korean Dietetic Association
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• v.27 no.3
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• pp.133-148
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• 2021

This study was undertaken to identify dietary patterns of Korean elderly people living alone, and to compare the quality of diet consumed. Data of 821 elderly people aged 65 years or older who were living alone, was obtained from the 2016~2018 National Health and Nutrition Survey. The percentage energy intake from 24 food groups was calculated, and a cluster analysis was applied to identify dietary patterns. General characteristics, energy and nutrient intake, nutrient adequacy ratio (NAR), mean adequacy ratio (MAR), and index of nutritional quality (INQ) were analyzed. Dietary variety score (DVS) and dietary diversity score (DDS) were subsequently calculated. The rice-centered diet group and mixed diet group were characterized as consuming higher intake of rice and a wider variety of food groups, respectively. The mean age and percentage of participants living in rural areas were higher, whereas education level and monthly income were lower, in the rice-centered diet group (P<0.001 for all). Intakes of energy and all other nutrients (except carbohydrate and thiamine) were lower in the rice-centered diet group (P<0.001 for all). The NAR for all nutrients (except thiamine), MAR, and INQs (except thiamine and iron) were significantly lower in the rice-centered diet group (P<0.001 for all). The rice-centered diet group had significantly lower DVS (P<0.001) and DDS (P<0.001), as compared with the mixed diet group (P<0.001). Due to the insufficient energy and nutrient intake in the rice-centered diet group, it is necessary to develop nutritional monitoring and customized nutrition policies for these individuals.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.217-224
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• 2021

Rice blast caused by Pyricularia oryzae, which is a major threat to food security worldwide, markedly decreases the yield of rice. Some rhizobacteria called 'plant growth-promoting rhizobacteria' inhibit plant pathogens and improve plant growth by secreting iron-chelating siderophores. The decreased availability of iron adversely affects the survival of pathogens, especially fungal pathogens, in the rhizosphere. This study aimed to determine the morphological diversity of siderophore-producing bacteria, analyze the type of siderophores produced by the bacteria, and examine their growth-inhibitory activity against Pyricularia oryzae. The rhizobacteria were isolated from the rhizosphere of Sembada Hitam variety of black rice plants in Pakem, Sleman, Yogyakarta, Indonesia. In total, 12 distinct isolates were screened for the production of siderophores. It was found that 9 out of 12 bacteria produced siderophore and most of them were Gram positive bacteria. The best siderophore-producing isolates with different type of siderophore were used in further studies. The IS3 and IS14 isolates were found to be the best siderophore producer that produced hydroxamate and mixed type of hydroxamate-carboxylate type of siderophore, respectively. In the dual culture assay, IS14 showed a strong antagonistic effect against Pyricularia oryzae by the 81.17% inhibition.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.112-112
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• 2017

Rice blast caused by Magnaporthe oryzae is one of the most serious diseases that affect the quantity and quality of rice production. The use of resistant rice varieties would be the most effective way to control the rice blast. However R gene incorporation into the rice variety takes time and pathogen could overcome the R gene effects after for a while. For monitoring the rice blast resistance gene distribution in Korean varieties, the four major blast resistance genes against M. oryzae were screened in a number of Korean rice varieties using molecular markers. Of the 120 rice varieties tested, 40 were found to contain the Pi-5 gene, 25 for the Pi-9 gene, 79 for Pi-b and 40 for the Pi-ta gene. None of these rice varieties includes tested 4 R genes. 3 R genes combination, Pi-5/Pi-9/Pi-b, Pi-5, Pi-9.Pi-ta, or Pi-9/Pi-b/Pi-ta were found in 12 varieties, the rice blast disease severity were showed as resistant in the rice verities containing Pi-9/Pi-b/Pi-ta R genes combination, respectively. Also pathogenic diversity of M. oryzae isolates collected in the rice field from 2004 to 2015 in rice field in Korea were analyzed using rice blast monogenic lines, each harboring a single blast resistance gene. Compatibility of blast isolates against rice blast monogenic lines carrying the resistance genes Pi5, Pi9, Pib, and Piz showed dynamic changes by year. It indicates that pathogen has high evolutionary potential adapted host resistances to increase fitness and would lead to rice blast resistance bred into the cultivar becoming ineffective eventually.

• Korean Journal of Community Nutrition
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• v.15 no.4
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• pp.536-549
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• 2010

The purpose of this study was to investigate food intake, dietary diversity and dietary pattern during the summer in middle aged and older adults living in Gugoksundam (Gurye, Goksung, Sunchang and Damyang counties), Jeonla Province located in southern part of Korea and known as one of the representative Korean longevity areas. Food intake and dietary diversity were assessed by using the data from 2 day-24 hour recall of 1,051 subjects (394 males and 711 females) aged 45 years and older (45-93 years in male, 45-105 years in female). The average ages of males and females were 70.7 years and 71.1 years, respectively. Average total daily food intake was significantly decreased with aging in both genders, and the average animal food intake ratio to total food intake was ranged 10~14% in 3 different age groups, 45~64 years, 65~74 years and 75 years and older. The contribution of each food group, in weight, to total food intake showed the descending order of grains, fruits, vegetables and alcohols in males, and grains, fruits, potatoes and meats in females. On daily intake amount of each food item, rice, watermelon, soju, kimchi, and potato were ranked on top 5 in descending order in males, and rice, watermelon, potato, kimchi and ylmukimchi in females. On intake frequency, rice, kimchi, onion, green pepper and potato were ranked on top 5 in descending order in both genders. Dietary variety score (DVS) and dietary diversity score (DDS) for the assessment of dietary diversity and balance were significantly decreased with aging in both genders. In food group intake pattern (DMGFV), 01101 type without consumption of dairy and fruits was the most prevalent, and only 3.6% of male and 3.9% of female subjects showed 11111 type, consumed all the 5 food groups a day. Dietary pattern of subjects was analyzed by cluster analysis with 18 food groups intake. Overall dietary pattern was classified into two clusters, one was more desirable and the other was less desirable. The percentage of subjects with more desirable dietary pattern was about 15% in male and 32% in female. In conclusion, most of our subjects living in Gugoksundam area were taking very simple diet with low amount of dairy products and fruits. These results indicate that nutrition intervention and education for older people living in rural areas should be focused on various food intake including dairy products and fruits.