• Journal of Ecology and Environment
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• v.36 no.3
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• pp.205-210
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• 2013

Cicuta virosa L. (Apiaceae) is a perennial emergent plant designated as an endangered species in South Korea. According to the former records, only four natural habitats remain in South Korea. A former study suggested that three of four populations (Pyeongchang: PC, Hoengseong: HS, Gunsan: GS) would be classified as different ecotypes based on their different morphological characteristics and life cycle under different environmental conditions. To evaluate this suggestion, we estimated genetic diversity in each population and distance among three populations by random amplification of polymorphic DNA. Seven random primers generated a total of 61 different banding positions, 36 (59%) of them were polymorphic. Nei's gene diversity and the Shannon diversity index increased in the order of PC < HS < GS, which is the same order of population size. In the two-dimensional (2D) plot of first two principal components in principal component analysis with the presence of 61 loci, individuals could be grouped as three populations easily (proportion of variance = 0.6125). Nei's genetic distance for the three populations showed the same tendency with the geographical distance within three populations. And it is also similar to the result of discriminant analysis with the morphological or life-cycle factors from the previous study. From the results, we concluded that three different populations of C. virosa should be classified as ecotypes based on not only morphology and phenology but genetic differences in terms of diversity and distance as well.

• The Korean Journal of Ecology
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• v.12 no.3
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• pp.133-144
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• 1989

The morphology and flowering time of two Suaeda japonica populations from different habitats, the creek and the bank of the mudflat in Sorae, were surveyed. And standard transplantation and reciprocal transplantation were carried out to determine whether their characteristics were genetically fixed or not. Also soil sample of these habitats were analyzed. The amounts of loss on ignition, maximum field capacity, total nitrogen, exchangeable calcium and potassium, and soluble phosphorus were found to be significantly different between two habitats. Leaf thickness, leaf width, leaf length, stem height number of branches, and number of seeds were significantly different between plants of two populations. And flowering times of two populations did not overlap. According to the results of transplantation, leaf width, leaf thickness, and flowering times were the same as those at their original habitat. But the stem lenght, leaf lenght, number of branches and unmber of seeds were not. Therefore, the differences in the leaf length, leaf thickness, and flowering time seemed to bo genetically fixed. It were suggested that the creek bank populations of Suaeda japoinica were to be considered as different ecotypes.

• Journal of Forest and Environmental Science
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• v.30 no.3
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• pp.285-292
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• 2014

Essential oil yields and chemical compositions from 5 populations of Chamaecyparis obtusa with several environmental factors were investigated through essential oil extracted distillation apparatus and metabolite profiling by GC-MS analysis. Among the populations, content of essential oil at Gokseong was significantly higher than other populations. To compare the several environmental factors affecting on chemical composition and essential oil yields from C. obtuse at Gokseong, the environmental factors (soil condition, temperature, humidity, and moisture content) were measured during 1 year. The essential oils at Goksung based on humidity on March, July, and November was significantly different from other months. The essential oils at Goksung based on temperature on July and August was significantly different from other months. The essential oils at Goksung based on the moisture content on September were significantly different from other months. The percentage of T-N, OM, and yield of oil at Gokseong were significantly different on from other populations. The main constituents of C. obtusa at all populations were ${\alpha}$-pinene, ${\beta}$-pinene, ${\alpha}$-terpinene, ${\gamma}$-terpinene, terpinene-4-ol, isobonyl acetate, terpinyl acetate, and cedar acetate. Specially, Essential oil compositions (%) of ${\alpha}$-terpinene and cedar acetate were higher at Gokseong than at other populations. The chemical compositions of essential oils were variable depend on populations and environmental conditions. Therefore, this study might be used as fundamental research on study for selection of high productive terpenoids and for understanding about biosynthesis of essential oils in C. obtusa.

• Journal of the Korea Safety Management & Science
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• v.3 no.3
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• pp.191-200
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• 2001

Parallel Genetic Algorithms partition the whole population into several sub-populations and search the optimal solution by exchanging the information each others periodically. Distributed Genetic Algorithm, one of Parallel Genetic Algorithms, divides a large population into several sub-populations and executes the traditional Genetic Algorithm on each sub-population independently. And periodically promising individuals selected from sub-populations are migrated by following the migration interval and migration rate to different sub-populations. In this paper, for the Travelling Salesman Problems, we analyze and compare with Distributed Genetic Algorithms using different Genetic Algorithms and using same Genetic Algorithms on each separated sub-population The simulation result shows that using different Genetic Algorithms obtains better results than using same Genetic Algorithms in Distributed Genetic Algorithms. This results look like the property of rapidly searching the approximated optima and keeping the variety of solution make interaction in different Genetic Algorithms.

• The Plant Pathology Journal
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• v.35 no.1
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• pp.51-62
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• 2019

A great variable response was observed when PP-3 and PP-J encumbered with 116 populations of root knot nematode (RKN) at two different temperatures ($25{\pm}2^{\circ}C$ and $30{\pm}2^{\circ}C$) and concentrations ($10^4$ and $10^5$ spores/ml). The PCR reaction amplified intergenic region between cytochrome oxidase subunit II gene (COII) and large subunit of rRNA gene (lrRNA) of the mitochondrial genome of different RKN species. The primer C2F3 and 1108 identified M. incognita with the highest frequency (52.6%) followed by M. javanica (36.8%) and M. arenaria (10.5%). The sizes of PCR products were 1.7 kb for M. incognita and M. javanica populations while populations of M. arenaria produced 1.1 kb fragment. The digestion with Hinf I yielded three different fragment length patterns on 1.5 % agarose gel. From current research it is concluded that intra-Meloidogyne genetic variability exist in RKN populations which have better encumbrance with P. penetrans.

• Plant Resources
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• v.8 no.3
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• pp.293-299
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• 2005

This study used RAPD markers to assume genetic diversity and variation in selected populations of Hovenia dulcis var. koreana. Ratio of polymorphic RAPD markers were 93.4% in selected populations of Hovenia dulcis Thunb., difference of genetic structure among populations and within populations showed 16.45%, 83.55%, respectively in amount of total genetic variation of 4 populations. Total gene diversity($H_T$) that show genetic diversity appeared 0.313 and coefficient of gene differentiation($G_{ST}$) that compare genetic differentiation of populations appeared 0.1645, analysis of AMOVA for variation among populations and within populations was significantly different (P<0.001). Genetic diversity of whole populations showed that 12.44% difference among population and 87.56% difference within populations. As a result, difference within populations was larger than difference among populations in genetic diversity. Nei's genetic distance and cluster analysis appeared that mean genetic distance among populations was 0.076, thus dividing two main groups and geographic relationship did not show in populations.

• The Korean Journal of Malacology
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• v.16 no.1_2
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• pp.11-16
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• 2000

The electrophoretic banding patterns of 6-phosphogluconate dehydrogenase (PGD) in the two different chromosomal ploidy groups of Gyraulus were compared. The monomeric or dimeric banding patterns or allelic variations in a locus of PGD were observed in four diploid populations (Osan, Sohre, Kimpo and Kangwha) of G. convexiusculus occurring in Korea, whereas the isozyme banding patterns encoded by at least 3 different loci were shown in the tetraploid populations of G. (Torquis) groups collected from Michigan, the U.S.A. Of 3 different tetraploid groups, G. (T.) circumstriatus group showed 3 monomorphic isozyme banding patterns, and the other 2 populations showed some allelic variations. Such results provided good evidence to differentiate tetraploid subgenus Torquis group from the diploid Gyraulus populations.

• The Korean Journal of Ecology
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• v.15 no.4
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• pp.377-386
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• 1992

Seasonal changes of symbiotic nitrogen-fixation activity and growth characteristics of four different natural populations of kummerowia striata were quantitatively analyzed during the growing period. the nitrogen-fixation activity of root nodules attained the maximum rates of 148, 132, 102 and 100$\muM\;C_2H_4\;\cdot\;g\;fw\;nodule^{-1}\;\cdot\;hr^{-1}$, respectively for sunny, multibranched, shade and unibranched populations at the optimum growth conditions. and the seasonal changes showed fluctuations by environmental conditions such as light, temperature, nutrient contents, water stress and plant ages, etc. The multibranched plant showed the greater amount of leaf and root nodule biomass, and the higher nitrogenase activity than the unibranched plant. the optimum conditions of leaf chloropht11 and water content of each organ indicated the active growth and the maximum fresh biomass of 4 different populations were 1.92, 1.85, 0.97 and 0.56 g $fw\cdotplant^{-1}$ for shade multibranched, sunny and unibranched populations, respectively.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.236-240
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• 2009

Tylenchulus semipenetrans, citrus nematode is an important phytopathogenic nematode and responsible for serious damage on citrus. However, little information is available about genetic variability of T. semipenetrans among different populations with variation of conventional diagnostic characteristics. In this study, we compared the morphometric and genetic characteristics among different populations. The mature female of T. semipenetrans collected in this study had thicker cuticle than those in the previous studies. In comparative sequence analysis of T. semipenetrans populations obtained from Jeju in Korea, we observed genetic variations within clones generated from single individuals. To determine whether variability among copies of nuclear ribosomal DNA sequences exists in the genome of T. semipenetrans, PCR-RFLP technique from individuals of Korean isolates with MseI and MspI restriction enzymes was used to prove experimentally that all populations have intra-specific variations. Restriction enzyme digestion created several fragments on 3.0% agarose gel corresponding to several haplotypes in all populations, though some populations displayed fragment deletion. The total length of fragments was larger than before digestion, indicating sequence heterogeneity within the genome of T. semipenetrans.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.2
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• pp.108-113
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• 2021

Detrimental effects of inbreeding have been studied by many researchers for a long time. However, only a few studies have shown the occurrence of inbreeding depression due to evolutionary changes as a purging process. In this study, two different populations (inbreeding and outbreeding) of Drosophila melanogaster were compared to assess inbreeding effects on artificial population bottlenecks. For inbreeding conditions, a couple of D. melanogaster (one virgin and one male) were selected from an inbred population and cultured in a vial. For outbreeding conditions, a couple of D. melanogaster were selected from different populations and cultured in a vial. There were significant differences in body lengths of adults, but not in other parameters such as the total number of adults, the rate of survival, and the rate of wing mutants. The mean body length of adults of outbreeding populations was longer than that of inbreeding populations in the first generation (G1; P = 0.004), but not in the second generation (G2; P = 0.066). Although the other three parameters (total number of adults, rate of survival, and rate of wing mutants) showed differences in their mean values between inbreeding and outbreeding populations, these differences were not statistically significant. This might be due to genetic purging. This study demonstrated one additional experimental case related to inbreeding depression in artificial bottlenecked populations. Further studies are necessary to confirm the clear interaction between inbreeding depression and genetic purging using more generations and replicates (or samples) of D. melanogaster.