• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.157-162
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• 2008

A total of 2,765 accessions were used as the initial set having both seed coat color and 100-seed weight data. As a result of molecular profiling using six SSR markers followed by stratification based on their usages, 335 accessions(12.1%) were selected by clustering based on UPGMA. Since 75 out of 335 accessions were mixed in phenotypic traits as a result of characterization, 260 accessions were finally set as a core set. This core set revealed nearly the same diversity compared with the other results on morphological traits of Korean soybean landraces. In total, 115 alleles(19.2 alleles per locus) were detected in the initial set and 79 alleles(13.2 alleles per locus) were detected in the core set. All 30 major alleles were present in the initial set and in the core set as well. In allele coverage, the core set was 71.4% of the initial set. These comparisons of number of alleles, gene diversity and coverage indicated that the core set represented the entire set well.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.169-172
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• 2006

Leaflet number of soybean controlled by Lf2 locus is the important trait in photosynthesis and plant type. The objective of this research was to identity molecular markers linked to the lf2 locus. A total of $115F_2$ plants were derived from a cross between normal three-leaflet type Sinpaldalkong (Lf2Lf2) and seven-leaflet mutant type T255 (lf2lf2). All leaflet counts of parents and $F_2$ individual plants were made in the field on fully expanded leaves on the main stem when terminal growth of the main stem had ceased. One-thousand 10-mer oligonucleotide RAPD primers and 664 SSR primers were used. The segregation ratios of 3 : 1 were observed in the $F_2$ population and the Chi-square values strongly suggested that the seven-leaflet was controlled by a single recessive gene. A genetic map was constructed from the 15 segregating markers (9 RAPDs, 5 SSRs, 1 lf2 locus). OPAD03 and OPAI13 RAPD markers were linked to the lf2 locus that controlled seven-leaflet type at a distance of 20.5 and 23.5 cM, respectively. Molecular markers identified in this study linked with lf2 locus will be helpful to locate lf2 locus on the public soybean molecular linkage map and would be useful for tagging the lf2 locus that controls seven-leaflet trait.

• Journal of Ginseng Research
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• v.35 no.4
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• pp.399-412
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• 2011

Little is known about the genetics or genomics of Panax ginseng. In this study, we developed 70 expressed sequence tagderived polymorphic simple sequence repeat markers by trials of 140 primer pairs. All of the 70 markers showed reproducible polymorphism among four Panax species and 19 of them were polymorphic in six P. ginseng cultivars. These markers segregated 1:2:1 manner of Mendelian inheritance in an $F_2$ population of a cross between two P. ginseng cultivars, 'Yunpoong' and 'Chunpoong', indicating that these are reproducible and inheritable mappable markers. A phylogenetic analysis using the genotype data showed three distinctive groups: a P. ginseng-P. japonicus clade, P. notoginseng and P. quinquefolius, with similarity coefficients of 0.70. P. japonicus was intermingled with P. ginseng cultivars, indicating that both species have similar genetic backgrounds. P. ginseng cultivars were subdivided into three minor groups: an independent cultivar 'Chunpoong', a subgroup with three accessions including two cultivars, 'Gumpoong' and 'Yunpoong' and one landrace 'Hwangsook' and another subgroup with two accessions including one cultivar, 'Gopoong' and one landrace 'Jakyung'. Each primer pair produced 1 to 4 bands, indicating that the ginseng genome has a highly replicated paleopolyploid genome structure.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.108-120
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• 2017

Modern watermelon cultivars (Citrullus lanatus [Thunb.] Matsum.& Nakai var. lanatus) have fruits with diverse phenotypes, including fruit shape, rind patterns, and flesh color. Molecular markers enable efficient selection of plants harboring desirable phenotypes. In the present study, publicly available DNA markers tightly linked to fruit shape, rind stripe pattern, and flesh color were evaluated using 85 watermelon accessions with diverse fruit phenotypes. For fruit shape, the dCAPS SUN - Cla011257 marker revealed an 81% of marker - trait match for accessions with elongated or round fruits. For rind stripe pattern, the SCAR wsb6-11marker was effective for selecting Jubilee-type rind pattern from other rind patterns. For flesh color, the Clcyb.600 and Lcyb markers derived from a mutation in the Lycopene ${\beta}$ - cyclase (Lcyb) gene, were effective at selecting red or yellow flesh. Forty-eight accessions possessing diverse fruit - related traits were selected as a reference array and their genetic relationships assessed using 16 SSR markers. At a coefficient of 0.11, the 48 accessions grouped into two major clades: Clade I and Clade II. Clade I subdivided further into subclades I - 1 and I - 2 at a coefficient of 0.39. All accessions with colored flesh were classified into Clade I, whereas those with white - flesh were classified into Clade II. Differences in fruit traits between subclades I - 1 and I - 2 were observed for rind pattern and fruit color; a majority of the accessions with Crimson-type striped or non-striped rind were grouped together in subclade I - 1, while most accessions in subclade I - 2 had a Jubilee - type rind stripe pattern. These results imply that reference array watermelon accessions possess distinguishable genetic structure based on rind stripe pattern. However, no significant grouping pattern was observed based on other fruit-related traits.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.250-257
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• 2008

Knowledge of genetic diversity and of the genetic relationships among elite breeding materials has had a significant impact on the improvement of crops. In maize, this information is particularly useful in i) planning crosses for hybrid and line development, ii) in assigning lines to heterotic groups and iii) in plant variety protection. We have used the SSR technique to study the genetic diversity and genetic relationships among 76 Korean waxy corn accessions, representing a diverse collection from throughout Korea. Assessment of genetic diversity among members of this group was conducted using 30 microsatellite markers. Among these 30 microsatellite markers, we identified a total of 127 alleles (with an average of 4.2 and a range of between 2 and 9 alleles per locus). Gene diversity at these 30 microsatellite loci varied from 0.125 to 0.795 with an average of 0.507. The cluster tree generated with the described microsatellite markers recognized two major groups with 36.5% genetic similarity. Group I includes 63 inbred lines, with similarity coefficients of between 0.365 and 0.99. Group II includes 13 inbred lines, with similarity coefficients of between 0.45 and 0.85. The present study indicates that the 30 microsatellite loci chosen for this analysis are effective molecular markers for the assessment of genetic diversity and genetic relationships between Korean waxy corn accessions. Specifically, this study's assessment of genetic diversity and relationships between a set of 76 Korean waxy corn inbred lines will be helpful for such activities as planning crosses for hybrid and line development and association mapping analyses of maize breeding programs in Korea.

• 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.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.304-310
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• 2011

In previous studies, we reported QTLs for grain weight (GW), qGW3 and for spikelets per panicle (SPP), qSPP3 linked to RM60 on chromosome 3 using advanced backcross lines derived from a cross between Oryza sativa ssp. Indica cv. Milyang 23 and O. glaberrima. The O. glaberrima alleles at this locus increased GW and spikelets per panicle in the Milyang 23 background. To further confirm and narrow down the position of the QTLs on chromosome 3, substitution mapping was performed using five lines containing the target O. glaberrima segment on chromosome 3. The size and position of the O. glaberrima segment on chromosome 3 were different in each line. These lines possessed 3-10 non-target O. glaberrima introgressions in the Milyang 23 background. These five lines were evaluated for seven agronomic traits including 1,000 grain weight and spikelets per panicle and also genotyped with seven SSR markers. Four lines were informative in delimiting the position of QTLs, qGW3 and qSPP3. Two lines with the O. glaberrima segment flanked by SSR markers, RM60 and RM523 displayed significantly higher values than Milyang 23 in GW and SPP whereas two lines without that O. glaberrima segment displayed no difference in GW and SPP compared to Milyang 23. The result indicates that two QTL, qGW3 and qSPP3 are located in the interval between RM60 and RM523 which are 1.2-Mb apart. Introgression lines having QTLs, qGW3 and qSPP3 would be useful materials not only to indentify the relationship between these two yield QTLs, but also to develop high yielding variety via marker-aided selection technology.

• Journal of Plant Biotechnology
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• v.39 no.1
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• pp.33-48
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• 2012

As a scientific curiosity to understand the structure and the function of crops and experimental efforts to apply it to plant breeding, genetic maps have been constructed in various crops. Especially, in the case of Brassica crop, genetic mapping has been accelerated since genetic information of model plant $Arabidopsis$ was available. As a result, the whole $B.$ $rapa$ genome (A genome) sequencing has recently been done. The genome sequences offer opportunities to develop molecular markers for genetic analysis in $Brassica$ crops. RFLP markers are widely used as the basis for genetic map construction, but detection system is inefficiency. The technical efficiency and analysis speed of the PCR-based markers become more preferable for many form of $Brassica$ genome study. The massive sequence informative markers such as SSR, SNP and InDels are also available to increase the density of markers for high-resolution genetic analysis. The high density maps are invaluable resources for QTLs analysis, marker assisted selection (MAS), map-based cloning and comparative analysis within $Brassica$ as well as related crop species. Additionally, the advents of new technology, next-generation technique, have served as a momentum for molecular breeding. Here we summarize genetic and genomic resources and suggest their applications for the molecular breeding in $Brassica$ crop.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.261-271
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• 2016

Citrus is an economically important fruit crop widely growing worldwide. However, citrus production largely depends on natural hybrid selection and bud sport mutation. Unique botanical features including long juvenility, polyembryony, and QTL that controls major agronomic traits can hinder the development of superior variety by conventional breeding. Diverse factors including drastic changes of citrus production environment due to global warming and changes in market trends require systematic molecular breeding program for early selection of elite candidates with target traits, sustainable production of high quality fruits, cultivar diversification, and cost-effective breeding. Since the construction of the first genetic linkage map using isozymes, citrus scientists have constructed linkage maps using various DNA-based markers and developed molecular markers related to biotic and abiotic stresses, polyembryony, fruit coloration, seedlessness, male sterility, acidless, morphology, fruit quality, seed number, yield, early fruit setting traits, and QTL mapping on genetic maps. Genes closely related to CTV resistance and flesh color have been cloned. SSR markers for identifying zygotic and nucellar individuals will contribute to cost-effective breeding. The two high quality citrus reference genomes recently released are being efficiently used for genomics-based molecular breeding such as construction of reference linkage/physical maps and comparative genome mapping. In the near future, the development of DNA molecular markers tightly linked to various agronomic traits and the cloning of useful and/or variant genes will be accelerated through comparative genome analysis using citrus core collection and genome-wide approaches such as genotyping-by-sequencing and genome wide association study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.81-88
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• 2007

The evaluation of soybean germplasm has mainly been carried out by morphological characters at Genetic Resources Division, Rural Development Administration (RDA). However, this information has been limited serving a diverse information for user and effectively managing the soybean germplasm. To resolve this problem, soybean collection conserved at RDA gene bank was profiled using nine soybean SSR (Simple Sequence Repeat) markers. Soybean SSR allele was confirmed using genescan and genotyper softwares of automatic sequencer for accurate genotyping of each accession and continuous accumulation of data. SSR profiling of soybean germplasm has been carried out from 2,855 (Satt458) to 4,368 (Satt197) accessions by locus. The number of allele revealed 267 with an average of 29.6 in total accession, and varied from a low of 21 (Satt532 and Satt141) to a high of 58 (Sat_074). Although the number of accessions of wild soybean is less than that of soybean landraces, Korean wild soybean is more variable than other soybean landraces populations in total number of alleles. However, Korean soybean landraces were more variable than Korean wild soybeans in 5 loci. In the allele frequency, wild soybean accessions showed an even distribution in all alleles and higher distribution in low ladder than in high ladder. Also, Korean soybean landraces revealed a high condensed frequency in Satt286 (202 bp, 232 bp), Chinese soybean landraces in Satt197 (171 bp) and Satt458 (173 bp), and Japanese soybean landraces in Sat_074 (244 bp) and Satt458 (170 bp). These SSR profile information will be provided as indications of redundancies or omissions of accessions and can aid in managing soybean collection held at RDA gene bank. The information on diversity analysis could help to enlarge the genetic diversity of materials in breeding program, and could be used to develop a core collection of soybean germplasm.