• Journal of Life Science
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• v.18 no.12
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• pp.1665-1670
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• 2008

Soybean oil is an important source of vegetable oil for human food and nonfood applications and accounts for approximately 22% of the world's total edible oil production. Improvement of the quality and quantity of soybean seed oil constituents is one of the most important objectives in soybean breeding. The objective of this study was to identify quantitative trait loci (QTLs) that control oleic, linoleic, and linolenic acid contents in soybean. The 117 $F_{2:10}$ recombinant inbred lines (RIL) developed from a cross of 'Keunolkong' and 'Shinpaldalkong' were used. Narrow-sense heritability estimates based on a plot mean on seed weight, protein and oil content were 0.85, 0.82 and 0.81, respectively. Eight independent QTLs for oleic acid content were identified from linkage group (LG) A2, C1, D2, F, G, L, and O. Seven QTLs for linoleic acid content were located on LG D1b, E, H, I and L. Oil content was related with five QTLs located on LG C1, H, J, K, and L. Oleic, linoleic, and linolenic acid have two common QTLs on LG C1 and L. Thus, we identified major loci improving soybean oil quality.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.321-336
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• 2018

Sesame (Sesamum indicum L.) is an important oilseed crop grown in tropical and subtropical areas. The objective of this study was to investigate the genetic relationships among 129 sesame landraces and cultivars using simple sequence repeat (SSR) markers. Out of 70 SSRs, 23 were found to be informative and produced 157 alleles. The number of alleles per locus ranged from 3 - 14, whereas polymorphic information content ranged from 0.33 - 0.86. A distance-based phylogenetic analysis revealed two major and six minor clusters. The population structure analysis using a Bayesian model-based program in STRUCTURE 2.3.4 divided 129 sesame accessions into three major populations (K = 3). Based on pairwise comparison estimates, Pop1 was observed to be genetically close to Pop2 with $F_{ST}$ value of 0.15, while Pop2 and Pop3 were genetically closest with $F_{ST}$ value of 0.08. Analysis of molecular variance revealed a high percentage of variability among individuals within populations (85.84%) than among the populations (14.16%). Similarly, a high variance was observed among the individuals within the country of origins (90.45%) than between the countries of origins. The grouping of genotypes in clusters was not related to their geographic origin indicating considerable gene flow among sesame genotypes across the selected geographic regions. The SSR markers used in the present study were able to distinguish closely linked sesame genotypes, thereby showing their usefulness in assessing the potentially important source of genetic variation. These markers can be used for future sesame varietal classification, conservation, and other breeding purposes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.492-497
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• 2014

Soybean (Glycine max L.) is crucial legume crop as source of high quality vegetable protein and oil, and Korea is regarded as a part of center of soybean origin. To expand the information of conserved genetic diversity, we analyzed the genetic variability of soybean collection mainly introduced Korean accessions using 75 microsatellite markers. A total of 1,503 alleles with an average value of 20.0 alleles were detected among 644 accessions. Korean collection revealed average allele number of 13.4 while Chinese, Japanese and Southeast Asian accessions showed 9.0, 5.4 and 6.5 mean alleles, respectively. Especially, Korean accessions showed more number of private allele per locus as 3.4 contrary to other geographical groups. The mean expected heterozygosity and polymorphic information content was 0.654 and 0.616, respectively, and expected heterozygosity values were not significantly distinguished according to the geographical groups. The phylogenetic dendrogram and deduced population structure based on DNA profiles of 75 SSR loci showed Korean accessions formed distinct gene pool against Chinese accessions, and could be divided into five subpopulations. Korean soybean accessions have specific genetic diversity and might be serve the valuable alleles for bio-industry as a part of the center of soybean origin.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.543-548
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• 2015

We studied the genetic impact of natural regeneration practices, such as Single seed tree, Group seed tree, Patch clear cutting and Alternate strip clear cutting systems, by comparing the nuclear microsatellite(nSSR) variation of post-practice natural regeneration one-year old seedlings of Pinus densiflora to that of pre-practice mature trees. The levels of genetic diversity of seedlings (A=13.6, $A_e$=4.3, $H_o$=0.571, $H_e$=0.597) were similar to those of mature trees (A=13.4, $A_e$=4.3, $H_o$=0.596, $H_e$=0.598) and the differences in the level of genetic diversity between seedlings and mature trees for each of the practices were not statistically significant. The degree of genetic differentiation between seedlings and mature trees was very low ($F_{ST}$=0.002) and the pairwise $F_{ST}$ values between seedlings and mature trees for all practices were less than 0.01. Overall, the natural regeneration practices appeared to have only minor impacts on the genetic diversity and the genetic composition in the studied P. densiflora stands. For a better understanding of the genetic effects of natural regeneration practices, subsequent studies such as temporal genetic variation of seedlings formed by crossing among post-practice mature trees should be considered.

• Molecules and Cells
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• v.25 no.4
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• pp.467-478
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• 2008

Simple sequence repeats (SSRs) and interSSR (ISSR) marker systems were used in this study to reveal genetic changes induced by artificial selection for short/long larval duration in the tropical strain Nistari of the silkworm Bombyx mori. Artificial selection separated longer larval duration (LLD) ($29.428{\pm}0.723days$) and shorter larval duration (SLD) ($22.573{\pm}0.839days$) lines from a base, inbred population of Nistari (larval span of $23.143{\pm}0.35days$). SSR polymorphism was observed between the LLD and SLD lines at one microsatellite locus, Bmsat106 ($CA_7$) and at two loci of 1074 bp and 823 bp generated with the ISSR primer UBC873. Each of these loci was present only in the LLD line. The loci segregated in the third generation of selection and were fixed in opposite directions. In the $F_2$ generation of the $LLD{\times}SLD$ lines, the alleles of Bmsat106 and $UBC873_{1074bp}$ segregated in a 1:1 ratio and the loci were present only in the LLD individuals. $UBC873_{823bp}$ was homozygous. Single factor ANOVA showed a significant association between the segregating loci and longer larval duration. Together, the two alleles contributed to an 18% increase in larval duration. The nucleotide sequences of the $UBC873_{1074bp}$ and $UBC873_{823bp}$ loci had 67% A/T content and consisted of direct, reverse, complementary and palindromic repeats. The repeats appeared to be "nested" (59%) in larger repeats or as clustered elements adjacent to other repeats. Of 203 microsatellites identified, dinucleotides (67.8%) predominated and were rich in A/T and T/A motifs. The sequences of the $UBC873_{1074bp}$ and $UBC873_{823bp}$ loci showed similarity (E = 0.0) to contigs located in Scaffold 010774 and Scaffold 000139, respectively, of the B. mori genome. BLASTN analysis of the $UBC873_{1074bp}$ sequence showed significant homology of (nt.) 45-122 with upstream region of three exons from Bombyx. The complete sequence of this locus showed ~49% nucleotide conservation with transposon 412 of Drosophila melanogaster and the Ikirara insertions of Anopheles gambiae. The A + T richness and lack of coding potential of these small loci, and their absence in the SLD line, reflect the active process of genetic change associated with the switch to short larval duration as an adaptation to the tropics.

• Journal of Ecology and Environment
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• v.38 no.1
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• pp.47-56
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• 2015

Ailanthus altissima, which is recognized as an invasive tree in the Western world, has been widely observed in Japan. To investigate how A. altissima expanded within-population and to new populations within a region, 446 A. altissima trees were sampled from three separate sites (A, B, and C) including 35 distantly positioned patches, with three chloroplast DNA markers and nine nuclear microsatellite markers. We detected 2, 2, and 3 chloroplast haplotypes in sites A, B, and C, respectively. In addition, 271, 40, and 41 nuclear genotypes were detected in sites A, B, and C, respectively. The clonal richness value was 0.85, 0.78, and 0.53 in sites A, B, and C, respectively. Most trees with the same genotypes were distributed in the same patch, indicating that range expansion by asexual reproduction was limited to a maximum of 45 meters. According to autocorrelation analysis, the extent of nonrandom spatial genetic structure was approximately 0-2 km in sites A and C. KINGROUP analyses showed that 812, 74, and 111 nuclear genotype pairs were detected to have kinship in sites A, B, and C, respectively. Most nuclear genotype pairs were detected within the same patches or sites. These results indicate that the number of A. altissima trees gradually increased from seeds, some of which were produced by trees within sites, meaning that this species could regenerate naturally. This shows the need for the future management of A. altissima as an invasive species in Japan.