• Horticultural Science & Technology
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• v.32 no.5
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• pp.607-613
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• 2014

Calcium has been associated with improved cold tolerance in many crops. The aim of this study was to investigate the changes in leaf cell $Ca^{2+}$ distribution and cell organelle ultrastructure of loquat (Eriobotrya japonica Lindl.) plants in response to cold stress at $-3^{\circ}C$, using transmission electron microscopy (TEM). Two loquat accessions, Zaozhong 6 (a commercial cultivar) and oakleaf loquat (a wild relative) were used. Cold tolerance, as measured by leaf browning rate, was higher in oakleaf plants, and calcium treatment improved cold tolerance in both species. Cold stress first induced inward transport of $Ca^{2+}$ from the intracellular space. Then, the imported $Ca^{2+}$ was aggregated around the chloroplast membrane, finally entering the chloroplast. This pattern of $Ca^{2+}$ distribution in leaf cells occurred earlier in Zaozhong 6 than in the wild loquat. With increasing time of cold exposure, the chloroplast membranes of Zaozhong 6 leaves were damaged, blurred and even disappeared, while those of wild oakleaf loquat leaves maintained their structure longer. In Zaozhong 6, cold stress induced a clear cavity between poorly structured granal thylakoids and vesicles appearing inside the chloroplast, while in oakleaf leaves cold stress had little effect on the ultrastructure of chloroplasts (although chloroplast membranes looked blurred). Loquat leaves accumulated free calcium ions around chloroplasts in response to cold stress, with earlier calcium accumulation occurring in the cold-sensitive cultivar Zaozhong 6 than in wild oakleaf loquat. These results demonstrate that these two loquat species have differences in both cold tolerance and calcium accumulation dynamics.

• Plant Resources
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• v.7 no.2
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• pp.93-103
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• 2004

Genetic background and phylogenetic relationships among 20 Korean wheat cultivars were assessed using microsatellites after amplifying with 13 SSR primer pairs. Average allele number per primer pair was 3.36. Genetic similarities for every pair of cultivars ranged from 0.42 to 0.97, with 0.69 of overall average. Korean cultivars were divided into two major groups based on microsatellite DNA polymorphisms. Group I consisted of relatively old cultivars developed until 1970s, and group II contained the recent cultivars developed during 1980s and 1990s. Amongst old elite cultivars/lines, ‘Yukseung 3’, ‘Norin 12’ and ‘Norin 72’ contributed most to the genetic background of cultivars belonging to group I, and ‘Norin 4’, ‘Norin 12’, ‘Norin 43’ and ‘Norin 72’ to group II, respectively. The phylogenetic relationship of Korean wheat cultivars was in accordance with the genealogical data of each cultivar. The genetic background of each cultivar was assessed from the point of breeding and germplasm management such as variety identification and duplicated accessions for assisting in developing a system for the registration of new variety based on the molecular characterization in future.

• Korean Journal of Medicinal Crop Science
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• v.13 no.2
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• pp.121-125
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• 2005

An analysis of RAPD-PCR (random amplified polymorphic DNA-polymerase chain reaction) was performed with three Angelica species (A. gigas Nakai, A. sinensis (Olive.) Diels and A. acutiloba Kitag) in an effort to distinguish between members of these three species. Two arbitrary primers (OPC02, OPD11) out of80 primers tested, produced 17 species-specific fragments among the three species. Eight fragments were specific for A. sinensis, four fragments specific for A. gigas, five specific for A. acutiloba. When primers OPC02 and OPD11 were used in the polymerase chain reaction, RAPD-PCR fragments that were specific for each of the three species were generated simultaneously. Primer OPC02 produced eight species-specific fragments: four were specific for A. sinensis, one for A. gigas, and three for A. acutiloba. Primer OPD11 produced nine speciesspecific fragments: four for A. sinensis, three for A. gigas, and two for A. acutiloba. The RAPD-PCR markers that were generated with these two primers should rapidly identify members of the three Angelica species. The consistency of the identifications made with these species-specific RAPD-PCR markers was demonstrated by the observation that each respective marker was generated from three accessions of each species, all with different origins. We also performed the RAPD-PCR analysis with the dried Angelica root samples that randomly collected from marketed and from the OPC02 primer, obtained a A. gigasspecific band and the band were cloned and sequenced.

• Korean Journal of Plant Taxonomy
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• v.50 no.1
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• pp.8-16
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• 2020

Complete chloroplast genome sequences provide detailed information about any structural changes of the genome, instances of phylogenetic reconstruction, and molecular markers for fine-scale analyses. Recent developments of next-generation sequencing (NGS) tools have led to the rapid accumulation of genomic data, especially data pertaining to chloroplasts. Short reads deposited in public databases such as the Sequence Read Archive of the NCBI are open resources, and the corresponding chloroplast genomes are yet to be completed. The V. dilatatum complex in Korea consists of four morphologically similar species: V. dilatatum, V. erosum, V. japonicum, and V. wrightii. Previous molecular phylogenetic analyses based on several DNA regions did not resolve the relationship at the species level. In order to examine the level of variation of the chloroplast genome in the V. dilatatum complex, raw reads of V. dilatatum deposited in the NCBI database were used to reconstruct the whole chloroplast genome, with these results compared to the genomes of V. erosum, V. japonicum, and three other species in Viburnum. These comparative genomics results found no significant structural changes in Viburnum. The degree of interspecific variation among the species in the V. dilatatum complex is very low, suggesting that the species of the complex may have been differentiated recently. The species of the V. dilatatum complex share large unique deletions, providing evidence of close relationships among the species. A phylogenetic analysis of the entire genome of the Viburnum showed that V. dilatatum is a sister to one of two accessions of V. erosum, making V. erosum paraphyletic. Given that the overall degree of variation among the species in the V. dilatatum complex is low, the chloroplast genome may not provide a phylogenetic signal pertaining to relationships among the species.

• Plant Resources
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• v.7 no.3
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• pp.187-194
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• 2004

Sequence-tagged site (STS) markers tightly linked to the bacterial leaf blight (BLB) resistance genes, xa5, xa13 and Xa21, were used in this study. A survey was conducted to find polymorphisms between the resistant and susceptible germplasm in rice. 500 of Korean varieties and 100 of landraces were evaluated in this study. STS marker, RG207 was used to having xa5 resistance gene of rice germplasm. 27 varieties of Korean germplasm showed resistant for xa5 gene. The RG136 an xa-13 marker resulted in a single band of approximately 1kb in all the rice accessions studied. In order to detect polymorphism, digestion of the polymerase chain reaction (PCR) product was performed using a restriction enzyme Hinf Ⅰ. The resistant lines resulted in two bands 0.5kb on digestion with Hinf Ⅰ, while the same enzyme did not digest the PCR product of susceptible lines. No polymorphism was detected in Korean varieties and landraces, indicating that they probably do not contain xa13 gene. pTA248 an Xa-21 marker detected a band of 1kb in the resistant lines and bands of either 750bp or 700bp in the susceptible lines. Among germplasm tested, there are no varieties and landraces with Xa21 resistant gene. The results of the germplasm survey will be useful for the selection of parents in breeding programs aimed at transferring these bacterial blight resistance genes from one varietal background to another.

• Korean Journal of Plant Resources
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• v.30 no.3
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• pp.298-310
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• 2017

Morphological variation between cultivated and weedy types of Perilla frutescens var. frutescens and P. frutescens var. crispa were studied in 327 germplasm by examining 17 morphological characters. The germplasm between the two varieties were varied for their qualitative and quantitative characters. The seed coat color of cultivated P. frutescens var. frutescens is commonly light brown and brown while deep brown color was observed in the weedy type P. frutescens var. frutescens and P. frutescens var. crispa. The leaf size, cluster length, plant height, flower number per cluster and seed weight in cultivated P. frutescens var. frutescens were significantly (P<0.05) different from weedy type P. frutescens var. frutescens and P. frutescens var. crispa. The cultivated P. frutescens var. frutescens exhibited significantly higher plant height (158.6 cm) compared to the weedy P. frutescens var. crispa (133.8 cm). Likewise, seed weight was significantly higher in cultivated (1.9 g) than in the weedy type of P. frutescens var. frutescens (1.6 g) and P. frutescens var. crispa (1.4 g). Principal component analysis (PCA) result showed that the first and second principal component cumulatively explained 86.6% of the total variation. The cultivated type P. frutescens var. frutescens and its weedy accessions were not clearly separated with P. frutescens var. crispa by PCA. Hence it requires the use of molecular markers for better understanding of their genetic diversity.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.4
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• pp.95-117
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• 1995

This study was carried out to investigate Korean native trees in the America landscape through arboretums, the plant inventory of America, computer files for accessions from Korea, source lists of plants and seeds, and seed and plant nursery company. The results were as follows; 1. Korean native trees introduced in America and Canada were 119 species, 116 species were being cultivated in arbrids were being sold in nurseries, new cultivars were selected from 32 species, and hybrids were bred from 5 species. 2. Abies koreana, Malus baccata, and Stewartia koreana were being cultivated in many arboretums and sold in many nurseries. Also there were new hybrids as well as new cultivars. 3. 25 species including Albizzia julibrissin were being cultivated in many arboretums and sold in many nurseries. Also there were new hybrids. 4. Ilex integra and Ilex rotunda were being cultivated in many arboretums and sold in many nurseries. There were no new cultivars, but there were new hybrids. 5. 44 species including Abies holophylla were being cultivated in many arboretums and sold in many nurseries. There were no new cultivars or hybrids. 6. Populus tremula var. davidiana was being cultivated in many arboretums. There were new cultivars of 'Erecta', 'Gigas', 'Pendula', but no new hybrids. They were not sold by any nurseries. 7. 41 species including Abies nephrolepsis were being cultivated in many arboretums. But they were not sold by any nurseries. They didn't have any new cultivars or hybrids. 8. Diospyros kaki 'Kyungsan Bansi', Elaeocarpus sylvestris var. ellipticus, and Pyrus serotina 'Dankae' were not being cultivated in arboretums in America but some nurseries were selling those species as well as new cultivars. 9. Only 3 species (Berchemia berchemiaefolia, Carpinus eximia, and Chionanthus retusus var. coreana which are native Korean plants) were not introduced in America or Canada.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.10a
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• pp.336-352
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• 1998

The horticultural seed industry has made great progress in the last fifty years of its history after the independence of this country. The industry has accomplished self-sufficiency in major vegetable seeds and has even gained international competitive edge in certain crop seeds, particularly in hybrid cultivar development. However, the industry is facing a crisis at present coming from excessive competition among the domestic seed companies as well as the foreign currency crisis of the country. Several major seed companies have already been acquired by multinational corporations. Many people in the country as well as agriculturists are concerned about this situation. Although it is true that the industry is undergoing hard times, this crisis can be turned into a chance for making new progress depending on the joint efforts of the groups responsible, i.e., private companies, public institutions, and policy makers. Therefore, we have to turn this crisis into an opportunity for self-reform and progress. We should not be discouraged or give up. We Propose some ideas for the Progress of the seed industry. Public institutions and policy makers should do such things in cooperation as 1) training human resources for future breeders, 2) securing a wide range of genetic resources and improvement of the management system, 3) basic science research including biotechnology, 4) releasing breeding stocks from germplasm enhancement through use of exotic accessions, 5) support for breeding region- or use-specific cultivars, and 6) collection of foreign agricultural information for breeding cultivars for overseas markets. Eventually the responsible group for the final development of commercial cultivars, production, sales and management is private companies. Therefore, private companies also should have to do their best to develop competitive cultivars with a missionary spirit and endeavor for both domestic and overseas markets in cooperation with public institutions. Management based on competition, professionalism and rationalism is also urged. We are going to conclude with optimism that we can make a new vault of progress once the private and public sectors closely cooperate for the development of Korean horticultural seed industry by overcoming this crisis.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.205-214
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• 2008

Blast disease caused by the fungal pathogen, Magnaporthe oryzae, is one of the most damaging diseases in rice. The use of resistant varieties is an effective measure to control the disease, however, many resistant varieties were broken down to their resistance effects by the differentiating of new virulent isolates. This study was done to analyze the haplotypes of 31 microsatellite markers linked to five major R genes and two QTLs and to identify the alleles for the putatively novel genes related to durable resistance to blast in 56 Korean japonica and four indica varieties. The 31 microsatellite markers produced 2 to 13 alleles(mean = 5.4) and had PICi values ranging from 0.065 to 0.860(mean=0.563) among the 60 rice accessions. Cluster analysis based on allele diversities of 31 microsatellite markers grouped into 60 haplotypes and ten major clusters in 0.810 genetic similarity. A subcluster IV-1 grouped of early flowering varieties harboring Piz and/or Pi9(t) on chromosome 6 and Pita/Pita-2 gene on chromosome 12. The other subcluster V-1 consisted of four stable resistance varieties Donghae, Seomjin, Palgong and Milyang20. The analysis of putative QTLs associated with seven blast resistance genes using ANOVA and linear regression showed high significance to blast resistance across regions and isolates in the markers of two genes Piz and/or Pi9(t) and Pita/Pita-2. These results illustrate the utility of microsatellite markers to identify rice varieties is likely carrying the same R genes and QTLs and rice lines with potentially novel resistant gene.

• Korean Journal of Plant Tissue Culture
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• v.28 no.4
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• pp.189-195
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• 2001

This study was carried out to investigate the effects of in vitro culture condition and among lines on growth pattern of lateral buds from nodal cuttings of Phalaenopsis flower stalks. The ratio of bud growing into shoot from nodal cuttings of flower stalks were 90.9% and 54.4% on MS and hyponex medium, respectively. The number of buds grown vegetatively were increased remarkably on the MS medium containing 5 mg/L BA. The rate of buds grown vegetatively was higher in basal and middle parts than in upper part of flower stalks. The flower stalk sections cultured at 25~28$^{\circ}C$ showed the highest ratio of vegetative growth. Medium contamination was decreased by pretreatment of etiolation to the flower stalk. However, the pretreatment did not show specific effects on shoot development and reduction of phenolic compound. Average shoot number which was formed from flower stalk segments in 27 of 30 accessions were 3.17, while high number of shoots were obtained from Phal. 3020 and Phal. 3039. The growth pattern of lateral buds in F$_1$hybrids was similar to that of their parents.