• Korean Journal of Environmental Biology
• /
• v.36 no.3
• /
• pp.424-437
• /
• 2018

The incidence of freshwater algal bloom has been increasing globally in recent years and poses a major threat to environmental health. Cyanobacteria are the major component of the bloom forming community that must be monitored frequently. Their morphological identities, however, have remained elusive, due to their small size in cells and morphological resemblances among species. We have analyzed molecular diversity and seasonal changes of cyanobacteria in Paldang Reservoir, Korea, using morphological and 16S rRNA pyrosequencing methods. Samples were collected at monthly intervals from the reservoir March-December 2012. In total, 40 phylotypes of cyanobacteria were identified after comparing 49,131 pyrosequence reads. Cyanobacterial genera such as Anabaena, Aphanizomenon, Microcystis and Synechocystis were predominantly present in samples. However, the majority of cyanobacterial sequences (65.9%) identified in this study were of uncultured origins, not detected morphologically. Relative abundance of cyanobacterial sequences was observed as high in August, with no occurrence in March and December. These results suggested that pyrosequencing approach may reveal cyanobacterial diversity undetected morphologically, and may be used as reference for studying and monitoring cyanobacterial communities in aquatic environments.

• Korean Journal of Environment and Ecology
• /
• v.10 no.2
• /
• pp.171-183
• /
• 1997

Diversity, abundance, species distributions and distributions of two strategists (specialist and geceralist) of butterflies were investigated monthly from June 1996 to Oct. 1996 by line transect method in the Chunbul-dong valley from park gate to Yangpok Sanjang. The butterfly faunas of the eight regions in Kwangwon province, Gyunggi proavince and Pusan were also studied by the same method to assess diversity and abundance of butterfly community in the study region. The 18 butterfly species in 7 families were found in this study and the 48 butterfly species in 7 families were distributed in the study area from thes study and the other researches. The 30 butterfly species reported in the other studies were not found in this study and Kaniska canace L. of them would be to decrease in density. In the study area, the common species were Artogeia melete M., Neptis sappho P. and Libythea celtis F.. The representative Korean common butterflies such as Artogeia rapae L., Colias erate E. and Papillio xuthus L. were rare. The PCA(Principal Component Analysis) ordinations indicate that habitat disturbance by human would be major factor for butterfly community and species distribution. Difference was not found in diversity according to habitat disturbance. Abundance, however, was higher in the disturbed region than the undisturbed region. Compared with the other regions, abundance was greatly lower and diversity was slightly lower than that of the other regions. Two strategists exhibited different distribution patterns. Generalists were found more commonly in the disturbed region and widely distributed in both of the disturbed region and the undisturbed region than specialists.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2018.10a
• /
• pp.68-68
• /
• 2018

A total of 47 core collections of pepper (Capsicum chinense Jacq.) conserved in National Agrobiodiversity Center (NAC) were studied under field condition at Jeonju. All accessions were characterized for their 14 qualitative and 16 quantitative characters. Results revealed that both qualitative and quantitative characters exhibited wide variation among the studied germplasm. Distribution of fruit characters (fruit length, width, and fruit wall thickness) among the accessions was positively skewed. Of the 47 accessions evaluated, 38.3% accessions had conical shaped fruits and mature fruit color was predominantly red (51.1%), orange (21.3%) and yellow (14.9%). Principal component analyses revealed that (i) 56.64% of the qualitative (fruit shape, color and fruit surface) variation and (ii) 89.42% of the quantitative (plant width, height and fruit maturity days) variation were explained by the first two components. Clustering revealed two groups and dendrogram revealed morphological variation among accessions. The phenotypic diversity exists in this core collections provide valuable information to improve agronomic traits in pepper breeding program.

• Journal of information and communication convergence engineering
• /
• v.6 no.2
• /
• pp.129-133
• /
• 2008

In this paper, modified power control algorithms are proposed for a satellite mobile communications system with ATC (ancillary terrestrial component). In order to increase system capacity and reduce the transmitting power of the user's equipment, we propose the modified power control scheme consisting of the modified closed-loop and open-loop power control. The modified CLPC (closed-loop power control) algorithm, combining the delay compensation algorithms and pilot diversity, is mainly applied to the ATC link in urban areas because it is more suitable to the short RTD (round-trip delay). In the case of rural areas where ATCs are not deployed or a signal is not received from ATCs, combining monitoring transmitting power equipment and OLPC (open-loop power control) algorithms using an efficient pilot diversity is mainly applied to the link between the user's equipment and the satellite. Two power control algorithms are applied equally to the boundary areas where two kinds of signals are received in order to ensure coverage continuity. The simulation results show that the modified power control scheme has good performance compared to conventional power control schemes in a GEO (geostationary earth orbit) satellite system with ATC.

• Journal of Korean Society on Water Environment
• /
• v.39 no.4
• /
• pp.288-301
• /
• 2023

This study aims to identify benthic macroinvertebrate fauna inhabiting at the mountain valley stream (Mt. Cheonggye) in Korea and the relationship between physical environmental factors and biological indices. Benthic macroinvertebrates were collected at five locations on August 24 and October 14, 2020, and were identified as 4 phyla, 7 classes, 16 orders, 42 families, and 72 species. Dominance ranged from 0.38 to 0.59, diversity 2.81 to 3.75, richness 3.25 to 4.63, evenness 0.65 to 0.84, and %EPT (Ephemeroptera-PlecopteraTrichoptera) richness value 42% to 73%, respectively. All sites were evaluated as a very good status by mostly biological indices based on tolerance of indicator organisms in Korea. As a result of principal component analysis, biological indices are classified into species-level indices and higher cartegory-level indices according to the taxonomic level of the indicator organism considered in each index. As a result of canonical correspondence analysis, it was confirmed that current velocity was a major factor that increased species richness and classified biological indices according to taxonomic category level. Water depth was a major factor related to the community indices, and the deeper the water depth, the lower the diversity and the evenness.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2018.10a
• /
• pp.43-43
• /
• 2018

Mutation breeding by radiation is useful for improving various crop species. Up to now, a total of 170 soybean mutant varieties have been released in the world, which is the second most registered varieties after rice. Despite the economic importance of soybean, there have been no TRAP marker system studies on genetic relationships between/among mutant lines. To develop a strategy of Mutant Diversity Pool (MDP) conservation, a study on the genetic diversity of 210 soybean mutant lines (8 cultivars and 202 mutants) was performed through a TRAP analysis. Sixteen primer combinations amplified a total of 551 fragments. The highest (84.00%) and lowest (32.35%) polymorphism levels were obtained with primers MIR157B + Ga5 and B14G14B + Ga3, respectively. The mean PIC values 0.15 varied among the primer combination ranging from 0.07 in B14G14B + Sal2 to 0.23 in MIR157B + Sa4. Phylogenetic, principal component analysis (PCA) and structure analysis indicated that the 210 lines belong to four groups based on the 16 combination TRAP markers. AMOVA showed 21.0% and 79.0% variations among and within the population, respectively. Overall, the genetic similarity of each cultivar and its mutants were higher than within other mutant populations. Our results suggest that the TRAP marker system may be useful for assessing the genetic diversity among soybean mutants and help to improve our knowledge of soybean mutation breeding.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.10
• /
• pp.1566-1572
• /
• 2020

Objective: The extensive breeding of commercial chickens has led to a sharp decrease in the resources of many indigenous chickens, especially the indigenous chickens in the southeastern coastal region, which are on the verge of extinction, and the indigenous chickens in the northwestern region of China, which are also at risk. However, there are few reports on the evaluation of genetic diversity and conservation of genetic resources of indigenous chickens in remote areas in the Northwest of China. Methods: In the present study, the genetic diversity and phylogenetic relationship of six indigenous chickens from different regions were studied based on variation in mitochondrial DNA control region (D-loop), and the degree of introgression from commercial breeds into these chickens was determined by the amount of haplotype sharing between indigenous and commercial breeds. Results: Twenty-five polymorphic sites and 25 haplotypes were detected in 206 individuals. Principal component analysis showed that the Jingning chicken had the highest genetic diversity among the six indigenous chickens. According to the degree of introgression, the six indigenous breeds may be involved in haplotype sharing with commercial breeds, and the introgression from commercial chickens into the Haidong chicken is the most serious. Conclusion: The genetic uniqueness of indigenous chickens has been eroded, so it is necessary to consider the protection of their genetic resources. Phylogenetic analysis suggests that the six indigenous chickens have two major matrilineal origins: one from Yunnan or its surrounding areas in China and the other from the Indian subcontinent.

• Horticulture, Environment, and Biotechnology : HEB
• /
• v.59 no.6
• /
• pp.875-888
• /
• 2018

Tulip (Tulipa L.) is one of the most important ornamental geophytes in the world. Analysis of molecular variability of tulips is of great importance in conservation and parental lines selection in breeding programs. Of the 70 genic microsatellites, 15 highly polymorphic and reproducible markers were used to assess the genetic diversity, structure, and relationships among 280 individuals of 36 wild and cultivated tulip accessions from two countries: Iran and the Netherlands. The mean values of gene diversity and polymorphism information content were 0.69 and 0.66, respectively, which indicated the high discriminatory power of markers. The calculated genetic diversity parameters were found to be the highest in wild T. systola Stapf (Derak region). Bayesian model-based STRU CTU RE analysis detected five gene pools for 36 germplasms which corresponded with morphological observations and traditional classifications. Based on analysis of molecular variance, to conserve wild genetic resources in some geographical locations, sampling should be performed from distant locations to achieve high diversity. The unweighted pair group method with arithmetic mean dendrogram and principal component analysis plot indicated that among wild tulips, T. systola and T. micheliana Hoog exhibited the closest relationships with cultivated tulips. Thus, it can be assumed that wild tulips from Iran and perhaps other Middle East countries played a role in the origin of T. gesneriana, which is likely a tulip species hybrid of unclear origin. In conclusion, due to the high genetic variability of wild tulips, they can be used in tulip breeding programs as a source of useful alleles related to resistance against stresses.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.1
• /
• pp.1-6
• /
• 2009

Genetic variability is an important component in the ability of populations to adapt in the face of environmental change. Severe human impacts reduced Muzzafarnagri sheep of India from 500,000 in 1972 to 10,989 in 1973-74. Here we report for the first time the effect of this population decline on levels of genetic variability at 13 FAO recommended ovine microsatellite loci and contrast levels of variability to that in a breed from the same geographical region, which differed in numbers, by an order of magnitude (Marwari sheep). Of the 13 loci, 100% were polymorphic in both breeds. A high degree of genetic variation was observed within populations in terms of both allele diversity (number of alleles per locus, >4) and gene diversity (expected heterozygosity, >0.5), which implied that there is still a substantial amount of genetic diversity at the nuclear loci in a declining population. Nevertheless, overall low number of alleles per locus and relatively less abundance of low frequency alleles in Muzzafarnagri sheep suggested that genetic variability has been comparatively reduced in this population. Bottleneck analysis indicated that a genetic bottleneck did not occur during the most recent decline. In addition, we found that the differentiation among populations was moderate ($F_{ST}$= 11.8%). This study on assessment of genetic effects of the population declines in ovines is a step towards identification of genetically impoverished or healthy populations, which could prove to be a useful tool to facilitate conservation planning in this important species of small ruminants.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.3 no.1
• /
• pp.70-79
• /
• 2000

Arbuscular mycorrhizal(AM) fungi have significant role for ecosystem structure and function. They are the major component of forest soil ecosystems and critically important for water and nutrient cycling in the system. To understand the ecology of AM fungi the fungal spores were collected, identified and counted in forest soils under various climatic and edaphic conditions. In relation to soil depth 90% of AM fungi spores and mycorrhizas distributed within 15cm soil depth. Number of spores per $100m{\ell}$ forest soil volume was 5 to 36 spores from 1 to 3 fungal species. AM fungal species diversity was higher in warmer climates, and more moist and fertile soils. The most frequently found species were Gigaspora decipiens irrespective of soil moisture and Gi. gigantea irrespective of soil fertility. In the Jeju island the soils of Cryptomeria japonica plantations and Miscanthus sinensis var. purpurascens meadow had more AM spores than the other soils. We suggest AM fungi be considered as keystones species when restoring a disturbed forest ecosystem.