• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.456-460
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• 2008

A new mungbean cultivar Daseon (Vigna radiata (L.) Wilczek) was derived from the cross between KM9003-2B-783 and Keumseong at the Jeollanamdo Agricultural Research ＆ Extension Services (JARES) in 2006. Daseon has erect growth habit, heart leaflet, greenish purple hypocotyl, black and straight pod when matured, and dull green seed surface. A thousand seed weight was 52 g, sprout yield ratio was 630%, and the anthocyanin (delphinidin 3-glucoside) of fresh sprouts contained 1.7 ug/g. The average plant height was 2 cm shorter than the check cultivar (Owool). It is field resistance to mungbean mottle virus, cercospora leaf spot, and powdery mildew. The average yield was 1.76 ton/ha, which was 21% more than check cultivar.

• Plant Breeding and Biotechnology
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• v.7 no.3
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• pp.186-199
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• 2019

We selected 68 Chinese maize inbred lines to understand the genetic diversity, population structure, and marker-trait associations for eight agronomic traits and 50 simple sequence repeats (SSRs) markers. In this study, effective traits, such as days of anthesis (DA), days of silking (DS), ear height (EH), plant to ear height ratio (ER), plant height (PH), and leaf width (LW) were divided into PC1 and PC2 by PCA analysis for maize inbred lines. Genetic diversity analysis revealed a total of 506 alleles at 50 SSR loci. The mean number of alleles per locus was 10.12. The averages of genetic diversity (GD) and polymorphic information content (PIC) values were 0.771 and 0.743, respectively. Based on a membership probability threshold of 0.80, the population structure revealed that the total inbred lines were divided into three major groups with one admixed group. A marker-trait association using Q + K MLM showed that nine SSR markers (bnlg1017, umc2041, umc2400, bnlg105, umc1229, umc1250, umc1066, umc2092, and umc1426) were related with seven agronomic traits. Among these SSR markers, eight SSR markers were associated with only one agronomic trait (DA, DS, ER, LL, LW, PH, and ST), whereas one SSR marker (umc1229) was associated with two agronomic traits (DA and ST). These results will help in optimizing the choice of inbred lines for cross combinations, as well as in selecting markers for further maize breeding programs.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.64-64
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• 2020

Bakanae disease, caused by several Fusarium species, imposes serious limitations to the productivity of rice across the globe. The incidence of this disease has been shown to increase, particularly in major rice-growing countries. Thus, the use of high resistant rice cultivars offers a comparative advantage, such as being cost effective, and could be preferred to the use of fungicides. In this research, we used a tropical japonica rice variety, Zenith, a bakanae disease resistant line selected as donor parent. A RIL population (F_8:9) composed of 180 lines generated from a cross between Ilpum and Zenith was used. In primary mapping, a QTL was detected on the short arm of chromosome 1, covering about 3.5 Mb region flanked by RM1331 and RM3530 markers. The resistance QTL, qBK1^Z, explained about 30.93% of the total phenotype variation (PVE, logarith of the odds (LOD) of 13.43). Location of qBK1^Z was further narrowed down to 730 kb through fine mapping using additional RM markers, including those previously reported and developed by Sid markers. Furthermore, there is a growing need to improving resistance to bakanae disease and promoting breeding efficiency using MAS from qBK1^Z region. The new QTL, qBK1^Z, developed by the current study is expected to be used as foundation to promoting breeding efficiency with an enhanced resistance against bakanae disease. Moreover, this study provides useful information for developing resistant rice lines carrying single or multiple major QTLs using gene pyramiding approach and marker-assisted breeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.161-171
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• 2020

Direct seeding is one of the rice seedling establishment methods that is increasingly being practiced by farmers to save labor and reduce costs. However, this method often causes poor germination under flooding conditions after sowing. In this study, we developed japonica elite lines with quantitative trait loci (QTL) associated with anaerobic germination (AG) tolerance to overcome poor germination and seedling establishment in wet direct seeding. The QTL introgression lines were developed from a cross between weedy photoblastic rice as the AG donor and the Nampyeong variety via phenotypic and genotypic selection. Compared to Nampyeong, the survival rates of the selected lines were improved by approximately 50% and 240% under field and greenhouse conditions, respectively. To improve selection efficiency by marker assisted selection, the QTL markers associated with AG tolerance were converted to cleaved amplified polymorphic sequence markers designed based on next-generation sequence analysis. These lines retained similar agronomic traits and yield potential to the parent, Nampyeong. Among these lines, we selected the most promising line, which exhibited high survival rate and good agricultural traits under flooding conditions and named the line as Jeonju643. This line will contribute to breeding programs aiming to develop rice cultivars adapted to wet direct seeding. This study demonstrates the successful application of marker-assisted selection to targeted introgression of anaerobic genes into a premium quality japonica rice variety.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.448-457
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• 2015

Developing rice lines with various amylose contents is necessary to diverse usages of rice in terms of raw materials for processed food production, and thereby to promote rice consumption in Korea. A rice mutant line, 'Namil(SA)-dull1' was established through sodium azide mutagenesis on 'Namil', a non-glutinous Korean Japonica rice cultivar. Namil(SA)-dull1' had dull endosperm characteristics and the evaluated amylose content was 12.2%. A total of 94 F2 progenies from a cross between 'Namil(SA)-dull1' and 'Milyang23', a non-glutinous Tongil-type rice cultivar, was used for genetic studies on the endosperm amylose content. Association analyses, between marker genotypes of 53 SSR anchor markers and evaluated amylose contents of each 94 F2:3 seeds, initially localized rice chromosome 6 as the harboring place for the modified allele(s) directing low amylose content of 'Namil(SA)-dull1'. By increasing SSR marker density on the putative chromosomal region followed by association analyses, the target region was narrowed down 0.94 Mbp segment, expanding from 28.95 Mbp to 29.89 Mbp, on rice chromosome 6 pseudomolecule. Among the SSR loci, RM7555 explained 84.2% of total variation of amylose contents in the $F_2$ population. Further physical mapping on the target region directing low amylose content of 'Namil(SA)-dull1' would increase the breeding efficiency in developing promising rice cultivars with various endosperm characteristics.

• Journal of Life Science
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• v.30 no.3
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• pp.239-249
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• 2020

Persimmon flowers are fruit-bearing female, pollen-bearing male, or hermaphrodite, containing both a pistil and a stamen. Using prominent PCNA persimmons as male parents is very important for breeding programs, as the selection procedure for new cultivars bearing male flowers requires a long time and a large field in a traditional crossbreeding method. To improve breeding efficiency through early selection of male flower-bearing plants at the seedling stage, analysis was performed on 88 major cultivars whose gender expressions are known, using two male flower selection markers recommended by Akagi et al. The OGI locus marker and DISx-AF4S marker results showed that 83 and 72 cultivars, respectively, matched in terms of gender expression and marker analysis. For the OGI locus marker, 890 plants were selected from 2,509 seedlings obtained from crossbreeding with the mother plant "Migamjosang," which was the breeding cultivar. Comparing the gender expression of the flowers and the marker with 1,186 crossbred seedlings, excluding the unfertilized and dead plants, inconsistencies were found in 401 plants (33.8%). For the DISx-AF4S marker, 636 plants were selected from 889 seedlings obtained from 12 cross-combinations. The results of the sex expression and marker analysis were compared to 379 plants, excluding the unfertilized and dead plants, and inconsistencies were found in 247 plants (65.2%). These results indicate that the examined DISx-AF4S and OGI locus markers would not be suitable for utilization in the breeding field.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.777-782
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• 2002

Reciprocal effects among local breeds and additive and heterosis effects were estimated for total milk production per lactation (TLP), lactation length (LL) and daily milk yield (DMY). Procedures for an optimum crossbreeding system were examined by comparing various crossbred combinations. Three data sets were chosen from the total records collected from 1962 to 1997. Data set I with a total of 5,938 records composed of 9 breed groups for reciprocal crosses, data set II with a total of 6,064 records composed of 5 breed groups for additive and heterosis effects and data set III with a total of 10,319 records composed of 42 breed groups for optimum crossbreeding system were analyzed. The least squares ANOVA was used. The reciprocal crosses between Red Sindhi and the Bangladeshi Local showed significant difference. When the Red Sindhi was used as cow, the cross was superior to the opposite in terms of the three performance traits. The results showed that additive breed effects on both TLP and DMY were positive and highly significant between Bos indicus and Bos taurus, whereas the individual heterosis effects were not significant. In general, any local breeds were improved two to three times by crossing with the Friesian once or twice. However, the effect was reduced when the grading up with the Friesian was repeated more than twice. On the other hand, when the local breed was crossed with the other breeds such as Holstein and Jersey, the improvement of TLP was less. Crossing the F1 cows with the Friesian bull gave further improvement. Almost the same trends were found also for LL and DMY. The local breeds and their crosses are raised mainly for draft animals, then it is recommended that the crossbreds between the local cows and Friesian are used for dairy purposes and more than 75% Friesian blood is used for beef.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.464-469
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• 2011

Virus diseases often cause serious damage to rice production in Asia. The lack of information on virus resistance genes has been a major obstacle for the breeding of resistant varieties. In order to identify DNA marker associated with resistance against rice stripe virus (RSV), the quantitative trait locus (QTL) was carried out using advanced backcross population developed from a cross between RSV-resistant tongil type cultivar Shinkwang and susceptible japonica cultivar Ilpum. A RSV resistance QTL $qSTV11^{SG}$ explaining 44.2% of the phenotypic variation was identified on chromosome 11 of Tongil type rice cultivar 'Shingwang'. $qSTV11^{SG}$ was tightly linked to DNA marker RM6897. The RM6897 divided as resistance type allele and susceptible type alleles. Twenty seven resistant varieties showed the resistant-type allele and 23 susceptible varieties were susceptible-type allele to the marker of RM6897. This results and the molecular markers presented here may be useful in rice breeding for improving RSV resistance in japonica rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.1
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• pp.8-17
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• 2021

As rice originates from tropical regions, low temperature stress during the germination stage in temperate regions leads to serious problems inhibiting germination and seedling establishment. Identifying and characterizing quantitative trait loci (QTLs) for low-temperature germination (LTG) resistance help accelerate the development of rice cultivars with LTG tolerance. In this study, we identified QTLs for LTG tolerance (qLTG5, qLTG9) and germination coefficient of velocity under optimal conditions (OGCV) (qOGCV7, qOGCV9) using 129 recombinant inbred lines (RILs) derived from the cross between a low-temperature sensitive line Milyang23 and a low-temperature tolerant variety Gihobyeo. qLTG9 and qOGCV9 were detected at the same location on chromosome 9. At both LTG QTLs (qLTG5 and qLTG9), the alleles for LTG tolerance were contributed by the japonica variety Gihobyeo. At qOGCV7 and qOGCV9, the alleles for low temperature tolerance were derived from Milyang23 and Gihobyeo, respectively. The RILs with desirable alleles at two or more QTLs, i.e., GroupVII: qLTG5+qLTG9 (qOGCV9) and GroupVIII: qLTG5+qOGCV7+qLTG9 (qOGCV9), showed stable tolerance under low-temperature stress. Our results are expected to contribute to the improvement of tolerance to low-temperature and anaerobic stress in japonica rice, which would lead to the wide adoption of direct-seeding practices.

• Korean Journal of Plant Resources
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• v.33 no.4
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• pp.293-302
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• 2020

Morphological characteristics of Ziziphus jujuba accessions, including 'Ilbon', were investigated to verify the possibility of 'Ilbon' as a breeding material. 'Ilbon' has smaller leaves and fruits and a lower total soluble solids content compared to the major Z. jujuba accessions. However, total polyphenol content and antioxidant capacity were highest in 'Ilbon' among the Z. jujuba accessions. In addition, 'Ilbon' could produce intact seeds and seed productivity of 'Ilbon' was highest compared with major Z. jujuba accessions. Principal component analysis and clustering analysis using the morphological characteristics of Z. jujuba accessions have been classified them to geographical origin. In particular, 'Ilbon' was clearly distinguished from the major Z. jujuba accessions. Therefore, 'Ilbon', which has the highest seed productivity and functional component, will be used as a material for cross breeding and will promote genetic study of Z. jujuba.