• Weed & Turfgrass Science
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• v.3 no.2
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• pp.110-113
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• 2014

The continuous use of acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibitors has led to the selection of herbicide resistant barnyardgrass populations in direct-seeded rice fields of Korea. This study was conducted to identify herbicide resistant barnyardgrass biotypes and to determine the cross- and multiple-resistance of them. 25% of the population collected from Taeahn was partially resistant to ACCase inhibitors and 22% collected from Kimjae were partially resistant to ALS inhibitors. However, 8.2% of the population from both sites was resistant to ALS and ACCase inhibitors. Resistance to sulfonylurea herbicide, flazasulfuron was identified from two barnyardgrass accessions collected from both Taeahn and Kimjae. One barnyardgrass accession from both sites was resistant to ACCase inhibitor, sethoxydim. The cross-resistance to ALS inhibitors was identified at one barnyardgrass accession from Taeahn and at two accessions from Kimjae. Further, crossresistance to ACCase inhibitors was also identified at barnyardgrass accessions from Taeahn and Kimjae. Multiple-resistance to flazasulfuron and sethoxydim was determined at four barnyardgrass accessions from Taeahn and at six accessions from Kimjae. Therefore, the herbicide mixture and sequences within a growing season or the herbicide rotation with different modes of actions across growing seasons are recommended to control herbicide-resistant barnyardgrass in infested fields.

• Research in Plant Disease
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• v.22 no.3
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• pp.133-144
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• 2016

Powdery mildew (Podosphaera xanthii) causes severe damage to pumpkin crops grown in open fields and plastic house. Initially, we used ten accessions of pumpkin species; Cucurbita pepo (3), C. maxima (2), C. moschata (2), and C. argyrosperma (3) to study the disease progress in different stages of seedling development. Commercial pumpkin varieties were used as susceptible host for inoculum management and young seedlings were inoculated by dusting powdery mildew spores on the cotyledons, 1-true-leaf and 2-true-leaf seedling stages. Based on initial study, we further evaluated 218 pumpkinaccessions for their resistance to powdery mildew in different seedling stages under plastic house. Area under disease progress curve (AUDPC) and relative AUDPC (rAUDPC) was higher in cotyledonary and 1-true-leaf than 2-true-leaf stage. Seedlings at cotyledons and 1-true-leaf seedling stage displayed more susceptibility to powdery mildew. Based on evaluation of 2-true-leaf stage, IT 110859 and IT 278459 from C. pepo and C. argyrosperma identified as resistant (<0.2). Of the 228 pumpkin accessions, 21 (9.2%) pumpkin accessions consisting of C. pepo (2), C. maxima (5), C. moschata (13), and C. argyrosperma (1) exhibited intermediate resistance (<0.4) to powdery mildew and these accessions are useful to growers for its rational management.

• Korean Journal of Plant Resources
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• v.30 no.3
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• pp.323-330
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• 2017

Eleutherococcus senticosus (Siberian ginseng) is an important medicinal tree found in northeast Asia. In this study, we analyzed the genome-wide distribution of microsatellites in E. senticosus. By sequencing 711 clones from an SSR-enriched genomic DNA library, we obtained 12 polymorphic SSR markers, which also revealed successful amplicons in E. senticosus accessions. Using the developed SSR markers, we estimated genetic diversity and population structure among 131 E. senticosus accessions in Korea and China. The number of alleles ranged from 2 to 11, with an average of 7.4 alleles. The mean values of observed heterozygosity ($H_O$) and expected heterozygosity ($H_E$) were 0.59 and 0.56, respectively. The average polymorphism information content (PIC) was 0.51 in all 131 E. senticosus accessions. E. senticosus accessions in Korea and China showed a close genetic similarity. Significantly low pairwise genetic divergence was observed between the two regions, suggesting a relatively narrow level of genetic basis among E. senticosus accessions. Our results not only provide molecular tools for genetic studies in E. senticosus but are also helpful for conservation and E. senticosus breeding programs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.5
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• pp.413-418
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• 2003

Genetic diversity and soybean sprout-related traits were evaluated in a total of 72 soybean accessions (60 Glycine max, 7 Glycine soja, and 5 Glycine gracilis). 100-seed weight (SW) was greatly varied and ranged from 3.2g to 32.3g in 72 soybean accessions. Positive correlation was observed between GR and hypocotyl length (HL), whereas negative correlation was observed between SW and hypocotyl diameter (HD). Re-evaluation by discarding two soybean genotypes characterized with low GR indicated that much higher correlation of sprout yield (SY) with HD and SW. Based on the principal component analysis (PCA) for sprout-related traits, 57 accessions were classified. Soybean genotypes with better traits for sprout, such as small size of seeds and high SY, were characterized with high PCA 1 and PCA 2 values. The seed size in second is small but showed low GR and SY, whereas the third has large seed, high GR and more than 400% SY. In genetic similarity analysis using 60 SSR marker genotyping, 72 accessions were classified into three major and several minor groups. Nine of twelve accessions that were identified as the representatives of soybean for sprout based on PCA were in a group by the SSR marker analysis, indicating the SSR marker selection of parental genotypes for soybean sprout improvement program.

• Journal of Forest and Environmental Science
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• v.37 no.3
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• pp.226-234
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• 2021

Two species, P. pyrifolia and P. ussuriensis, of the genus Pyrus native to Korea, are valuable genetic resources that can be used for food, dietary supplement, pharmaceutical, and cosmetics. Bioactive compounds of the plant leaves are the main components that are used for the products. Farmers had cultivated a few individuals from the wild to produce fruits or leaves for traditional remedy or tea; however, bioactive components of their leaves are not tested. We selected some trees from the natural stand that have distinct traits for the improvement program. We investigated the bioassay on the extracts' bioactive compounds and antioxidant capacity from the selected accessions and other accessions, including newly developed cultivars. The contents of the phenolic compounds and flavonoids from the leaf extracts of the selected accessions were higher than the commonly cultivated trees in both species but lower than 'Sanhyang' in P. ussuriensis. The antioxidant capacity was measured using two assay methods, DPPH and ABST. The selected cultivars also had higher inhibitory activity than common trees. The selected accession 'Cultivar 3' in P. pyrifolia had the highest radical scavenging activity than others. Although leaves of the accessions were used only in this study, all three selected individuals have the potential for cultivar in containing high bioactive compounds and antioxidant capacity.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.63-63
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• 2019

Tea plant (Camellia sinensis (L.) O. Kuntze) has been cultivated widely in many developing Asian, African, and South American countries, where it is the most widely consumed beverage in the world next to water. It has critical importance to understand the genetic diversity and population sturcutre for effective collection, conservation, and utilization of tea germplasm. In this study, 410 tea accessions collected from South Korea were analyzed using 21 SSR markers. Among 410 tea accessions, 85.4% (310 accessions) accessions were collected from Jeollanam-do. A total of 286 alleles were observed, and the genetic diversity and evenness were estimated to be averagely 0.79 and 0.61, respectively, across all the tested samples. Using discriminant analysis of principal components, the four clusters were detected in 410 tea accessions. Among them, cluster 1 showed higher frequency of rare alleles (less than 1%) than other clusters. Using calculation of the index of association and rbaD value, each cluster showed a clonal mode of reproduction. The result of AMOVA showed that most of the variation observed was within populations (99%) rather than among populations (1%). Our results might contribute to provide data about genetic diversity for the conservation of tea germplasm and for future breeding programs.

• Plant Resources
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• v.4 no.3
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• pp.121-129
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• 2001

Intraspecific genetic diversity of sixteen accessions of Mogolian Alliums including fifteen species was investigated using randomly amplified polymorphic DNA (RAPD) analysis. Twenty three out of forty primers revealed scorable polymorphism. A total of 440 RAPD markers were generated on the 16 accessions of Mongolian Alliums. Among 440 RAPDs assayed, 439 were polymorphic with a mean polymorphic rate of 99.7%. Unweighted pair-group method using an arithmetic average (UPGMA) cluster analysis using RAPD data separated the 16 Allium accessions into two broad groups at similarity index 0.70. The clustering of the species was closely related with previous classification between A. altaicum and A. fistulosum. In addition, a high genetic similarity was showed between A. cepa and A. tagar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.26-31
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• 1999

This experiment was conducted to evaluate genetic variation in 48 rice accessions (Oryza sativa L.) using AFLP and RAPD markers. For AFLP, a total of 928 bands were generated with 11 primer combinations and 327 bands (35.2%) of them were polymorphic among 48 accessions. In RAPD analyses using 22 random primers 145 bands were produced, and 121 (83.4%) were polymorphic among 48 accessions. Each accession revealed a distinct fingerprint by two DNA marker systems. Cluster analysis using AFLP-based genetic similarity tended to classify rice cultivars into different groups corresponding to their varietal types and breeding pedigrees, but not using RAPD-based genetic similarity. The AFLP marker system was more sensitive than RAPD in fingerprinting of rice cultivars with narrow genetic diversity.

• Journal of Plant Biotechnology
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• v.33 no.2
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• pp.139-145
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• 2006

The present study is the first report of molecular variations in different accessions of Rauvolfia tetraphylla L.f, a medicinally important plant collected from seven locations of Andhra Pradesh, India. Molecular analysis was carried out using RAPD markers. Out of the 40 primers screened from OPA and OPC Kts, a total of 205 scorable polymorphic markers out of 397 total markers were generated. Polymorphism of 51.6% was found with 3 unique markers. Levels of genetic diversity within accessions i.e., the genetic distance ranged from 0.816-0.932. Cluster analysis based on Dice coefficient showed two major groups indicating that mostly in cross-pollinated plants, high levels of differentiation among accessions exists independent of geographical distance. Hence the results of the present study can be seen as a starting point for future researches on the population and evolutionary genetics of this species. Understanding such variation would also facilitate their use in various conservational management practices, rootstock breeding and hybridisation programmes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.409-417
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• 2012

This study was conducted to determine the variation of phenolic compounds in the leaf and stem of 131 accessions of Lycium chinesis Miller. The levels of total phenolic compounds in the leaf of L. chinesis ranged between 8.8 to $14.9mg\;g^{-1}$ and among them 60% of the accessions belong between 11.6 and $13.5mg\;g^{-1}$ for the content of phenolic compounds in the leaf. The accession CB03286-89 contained the highest total phenolic compounds among the accessions tested, which was 1.7-fold higher than that of the lowest content accession CBP03310-250. In the stem, the total phenolic compound of 131 accessions of L. chinesis ranged from 6.8 to $12.4mg\;g^{-1}$, showing slightly lower level than that in the leaf. The content of (+)catechin was highest in the leaf and stem of accession CB03286-89 and Japan No.1, respectively. Myricetin was detected in the leaf of seven accessions (i.e. Geumsan jaerae, Japan No.1, China collection No.1, CL32-13, CB04329-13, China collection No.12 and CB03286-89) and in the stem of five accessions (i.e., Japan No.1, China collection No.1, China collection No.12, CB03286-89 and 99797). Accessions had a great influence on the content of phenolic compounds. So, accessions-specific phenolic compound profiles might be helpful for commercial use or production of phenolic compounds in L. chinesis.