• Weed & Turfgrass Science
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• v.2 no.3
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• pp.230-235
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• 2013

Amaranths (Amaranthus sp.), an endemic American crop, are now grown widely across the world. This study used 14 simple sequence repeat (SSR) markers to analyze the genetic diversity of 74 amaranth accessions from the United States, with eight accessions from Australia as controls. One hundred twenty-two alleles, averaging eight alleles per locus, were observed. The average major allele frequency, expected heterozygosity, and polymorphism information content (PIC) were 0.44, 0.69, and 0.65, respectively. The structure analysis based on genetic distance classified 77 accessions (94%) into three clusters, while five accessions (6%) were admixtures. Among the three clusters, Cluster 3 had the highest allele number and PIC values, while Cluster 2 had the lowest. The lowest FST was between Clusters 1 and 3, indicating that these two clusters have higher gene flow between them compared to the others. This finding was reasonable because Cluster 2 included most of the Australian accessions. These results indicated satisfactory genetic diversity among U.S. amaranths. These findings can be used to design effective breeding programs involving different plant characteristics.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.171-176
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• 2008

The agronomic traits, such as days to flowering and maturity, plant height, 100-seed weight and seed filling period, are quantitatively inherited and important characters in soybean(Glycine max L. Merr.). A total of 126 $F_5$ recombinant inbred lines(RILs) developed from the cross of PI 171451$\times$Hwaeomputkong were used to identify quantitative trait loci(QTLs) for days to flowering(FD), days to maturity(MD), plant height(PH), 100-seed weight(SW), number of branches(NB) and seed filling period(FP). A total of 136 simple sequence repeat(SSR) markers segregated in a RIL population were distributed over 20 linkage groups(LGs), covering 1073.9 cM of the soybean genome with the average distance between adjacent markers of 7.9 cM. Five independent QTLs were identified for FD, three for MD, two for PH, three for SW, one for NB and one for FP. Of these, three QTLs were related to more than two traits of FD, MD, PH, NB and FP and mapped near the same positions on LGs H and O. Thus, these traits could be correlated with biologically controlled major QTLs in this soybean RIL population.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.441-451
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• 2009

In this study, 29 simple sequence repeat (SSR) markers were used to analyze the genetic diversity and population structure of 125 rice accessions from 40 different origins in Africa, Asia, Europe, South America, and Oceania. A total of 333 alleles were detected, with an average of 11.5 per locus. The mean values of major allele frequency, expected heterozygosity, and polymorphism information content (PIC) for each SSR locus were 0.39, 0.73, and 0.70, respectively. The highest mean PIC was 0.71 for Asia, followed by 0.66 for Africa, 0.59 for South America, 0.53 for Europe, and 0.47 for Oceania. Model-based structure analysis revealed the presence of five subpopulations, which was basically consistent with clustering based on genetic distance. Some accessions were clearly assigned to a single population in which >70% of their inferred ancestry was derived from one of the model-based populations. In addition, 12 accessions (9.6%) were categorized as having admixed ancestry. The results could be used to understanding the genetic structure of rice cultivars from these regions and to support effective breeding programs to broaden the genetic basis of rice varieties.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.46-46
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• 2020

Finger millet is more nutritious than other and millets and widely cultivate in tropical regions of the world. Furthermore, it is more tolerant against biotic and abiotic stresses such as pest, drought and salt. For this reason, finger millet is one of the putative crops to introduce and cultivate on reclaimed land and prepare the global climate exchange in Korea. In present study, genetic diversity and structure of different populations of finger millet from Africa and South Asia was examined at molecular level using newly developed EST-Simple Sequence Repeat (EST-SSR) markers. In total, 46 primers produced 292 alleles in a size range of 100-500 bp and mean Polymorphism Information Content (PIC) and Marker Index (MI) were 0.372 and 1.04, respectively. 46 primers showed polymorphism and 21 primers were identified as having a PIC value above 0.5. Principal coordinates analysis and the dendrogram constructed out of combined data of both markers showed grouping of finger millet accessions to their respective area of collection. The 156 accessions were more classified into four groups, such as three groups of Africa collection and one group of Asia. Results of present study can be useful in identifying diverse accessions and management of this plant resource. Moreover, the novel SSR markers developed can be utilized for various genetic analyses in this species in future.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.546-551
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• 2011

Chrysanthemums, often called mums or chrysanths, belong to the genus Chrysanthemum, which includes about 30 species of perennial flowering plants in the family Asteraceae. We extracted DNA from Dendranthema grandiflorum ('Smileball') to construct a simple sequence repeat (SSR)-enriched library, using a modified biotin-streptavidin capture method. GS FLX (Genome Sequencer FLX System which provides the flexibility to perform the broad range of applications) sequencing (at the 1/8 run specification) resulted in 18.83 mega base pairs (Mbp) with an average read length of 280.06 bp. Sequence analyses of all SSR-containing clones revealed a predominance of di-nucleotide motifs (16,375, 61.5%) followed by tri-nucleotide motifs (6,616, 24.8%), tetra-nucleotide motifs (1,674, 6.3%), penta-nucleotide motifs (1,283, 4.8%), and hexa-nucleotide motifs (693, 2.6%). Among the di-nucleotide motifs, the AC/CA class was the most frequently identified (93.5% of all di-nucleotide types), followed by the GA/AG class (6.1%), the AT/TA class (0.4%), and the CG/GC class (0.03%). When we analyzed the distribution of different repeat motifs and their respective numbers of repeats, regardless of the motif class, of 100 SSR markers, we found a higher number of di-nucleotide motifs with 70 to 80 repeats; we also found two di-nucleotide motifs with 83 and 89 repeats, respectively, but their product lengths were within optimum size (297 and 300 bp). In future work, we will screen for polymorphisms of possible primer pairs. The results will provide a useful tool for assessing molecular diversity and investigating the population structure among and within Chrysanthemum species.

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.04a
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• pp.26-26
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• 2018

• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.889-897
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• 2018

Currently, there is a lack of genetic markers capable of effectively detecting polymorphisms in Clematis. Therefore, we developed new markers to investigate inter- and intraspecific diversity in Clematis. Based on the complete chloroplast genome of Clematis terniflora, simple sequence repeats were explored and primer pairs were designed for all ten adequate repeat regions (cpSSRs), which were tested in 43 individuals of 11 Clematis species. In addition, the nuclear ITS region was sequenced in 11 Clematis species. Seven cpSSR loci were found to be polymorphic in the genus and serve as markers that can distinguish different species and be used in different genetic analyses, including cultivar identification to assist the breeding of new ornamental cultivars.

• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.83-90
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• 2008

Two hundred and sixty Korean soybean landrace accessions were analyzed for polymorphism at 92 simple sequence repeat(SSR) loci. The 995 identified alleles served as raw data for estimating genetic diversity and population structure. The number of alleles at a locus ranged from three to 27 with a mean of 10.4 alleles per locus. $F_{ST}$ values estimated by analysis of molecular variance(AMOVA) using SSR data set were 0.018, 0.027, and 0.016 for usage, collection site and maturity groups, respectively, indicating little genetic differentiation. The model-based clustering analysis placed the accessions into three clusters(K=3) with 0.0503 of $F_{ST}$, indicating moderate genetic differentiation. Duncan's Multiple Range Test at K = 3 on the basis of 18 quantitative traits revealed that one cluster was mainly differentiated from the other two clusters by seed related traits and the other two clusters were differentiated from each other by biochemical traits. Genetic structure of Korean soybean landraces was differentiated by model-based clustering and supported by their phenotypic traits in part. This preliminary study could be the first step towards more efficient germplasm management and utilization of soybean landraces and helpful in association studies between genotypic and phenotypic traits in Korean soybean landraces.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.1
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• pp.1-7
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• 2018

Information on the patterns of genetic diversity and population structure is essential for the rational use and efficient management of germplasms; accurate information aids in monitoring germplasms, and can also be used to predict potential genetic gains. In this study, we assessed genetic diversity, focusing on Korean rice accessions for theand their sustainable conserved diversity. Using DNA profiling with 12 simple sequence repeat (SSR) markers, we detected a total of 333 alleles among 2,016 accessions. The number of alleles ranged from 21 to 53, with an average of 27.8. Average polymorphism information content was 0.797, with the lowest being 0.667 and the highest 0.940. CA cluster analysis and the model-based population structure revealed two main groups that could be subdivided into five subgroups. Analysis of the molecular variance study based on the SSR profile data showed 5% variance among the profiles, whereas we recorded 93% variance among individuals and 2% variance within individuals. Specifically, the utilized diversity for of the breeding program is restricted in that cultivars were located in limited clades. These results revealed that preserving the diversity of Korean landraces could be useful sources for breeding new rice cultivars, and cwould be the basis for the sustainable conservation and utilization of a Korean rice germplasm.

• Journal of Crop Science and Biotechnology
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• v.11 no.4
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• pp.243-248
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• 2008

The bean bug Riptortus clavatus Thunberg (Heteroptera: Alydidae) is an important pest, causing serious yield loss in soybean. But the information on mechanism of resistance to R. clavatus is limited. The objective of this study was to identify QTLs for R. clavatus resistance using simple sequence repeat (SSR) markers in a soybean population of recombinant inbred lines (RILs) developed from the cross PI 171451 ${\times}$ Hwaeomputkong. A genetic map from this population was constructed with a total of 136 SSR markers covering 1073.9 cM on 20 linkage groups (LGs). With 126 $F_5$ RILs, two independent QTLs for resistance to R. clavatus were mapped on LGs B1 and C2. The amount of phenotypic variation explained by these QTLs ranged from 12 to 16%. PI 171451 showed an escape response to R. clavatus. Under feeding conditions, 14.4% of RILs showed greater resistance to R. clavatus than the resistant parent. The resistance to R. clavatus in soybean from PI 171451 was incomplete and quantitatively inherited and the QTLs for resistance to R. clavatus detected in the RIL population were not significantly affected by epistatic interactions.