• Proceedings of the Plant Resources Society of Korea Conference
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• 2001.11a
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• pp.15-19
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• 2001

The wild Pyrus plants belong to the deciduous woody plants in Rosaceae family. Most are cultivated for fruit productions, but some for ornamental plants. There are 5 Pyrus species including Pyrus ussuriensis and 8 varieties cultivated in Korea. In Korea, these plants are populated near villages or on the hills, and they are easily propagated since their fruit are very Juicy and quite big In size. Plant breeding to get improved cultivars Is not difficult because the Pyrus plants are easy to cross breeding among its genus. Because not only this reason but there have been shown lots of variation in wild groups, the Pyrus plants inhabited In Korea are excellent deciduous woody plants and favorable fruit trees to develop ornamental plants. It is necessary to develop many kinds of fruit trees and ornamental trees containing genetically different character, so that it will be satisfied for many different people's taste and demands Collecting lots of wild plant resource with diverse genes is necessary for plant breeding.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.133.1-133
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• 1998

No Abstract, See Full Text

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.253-259
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• 2011

In this studies, contents and activities of antioxidative substances in the fruits of a pear cultivar and five Korean wild pear lines were investigated. The content of total phenolic compounds was highest with Pyrus pyrifolia var. culta "Shingo" (7.68 $mg{\cdot}g^{-1}$, D.W.) while total flavonoids was highest with P. ussuriensis var. acidula (5.66 $mg{\cdot}g^{-1}$, D.W.). The contents of total polyphenols and flavonoids varied according to plant species, but in general pyrifolia lines had higher total polyphenols than total flavonoids whereas in ussuriensis lines total flavonoid contents were higher than total polyphenols. The scavenging effects of DDPH radicals was highest with highest with P. ussuriensis var. seoulensis ($RC_{50}$=1.45 $mg{\cdot}mL^{-1}$) and that of ABTS radicals was highest with P. ussuriensis var. acidula ($RC_{50}$=0.69 $mg{\cdot}mL^{-1}$). A pear cultivar "Shingo" showed highest total polyphenol content, but scavenging activity of DDPH and ABTS radicals was lowest. The fruits of P. ussuriensis var. seoulensis contained low level of phenolic compounds, but their scavenging effects on two radicals was superior. Ferrous ion chelating effect was high in P. pyrifolia var. culta (98.93%), and in P. ussuriensis var. sinensis (68.71%), but two species had low scavenging activity. The content of phenolic compounds in wild pears was not always directly proportional to the radical scavenging activity. Neither radical scavenging activity was to ferrous ion chelating activity. In conclusion the fruits of P. ussuriensis var. acidula, P. ussuriensis var. seoulensis, and P. ussuriensis var. sinensis had great potential for the development of new antioxidative functional food because their antioxidative activity is higher or at least similar to P. pyrifolia var. culta. However, due to their different levels of antioxidative effects, the development of methods of using them jointly, not singly, to obtain maximum level of antioxidants is recommended.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.96-106
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• 2002

Five major naturally populated habitats around the Mt. Daeduk, Gangwon province for wild Chuiangne (Pyrus ussuriensis var. acidula) are mostly located on the southeast side of the mountains at 1,216-1,306ｍ in altitude at sea level and are in very good sunney areas. The total of 96 taxa dividing into 40 families, 79 genera 84 species and 12 varieties have in these areas. Most of these plants are heliophytes, which love sunshine, Compositaes such as Artemisia stolonifera, Synurus deltoides, or Rosaceaes like Potentilla fragarioides var. major are also shown. These areas have been unknown destroyed, so it is possibly thought the second transition has been progressed. The index of species diversity of plant groups in these areas is 4.715-5.270 based on the Shannon-Wiener's method. The wild Chuiangne with 34.15％, which are 5-10㎝ DBH, have been found in habitats. The vegetation around the habitats must be managed by the man in order to keep sound growth of the wild Chuiangne.

• Journal of Korean Society of Forest Science
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• v.97 no.4
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• pp.452-457
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• 2008

In order to develop an efficient micropropagation technique effect of plant growth regulators (PGRs) affecting on shoot proliferation from shoot apex in Pyrus ussuriensis was tested. Generally, there was no conspicuous effect on shoot induction by the treatment of PGRs and one or two shoots/explant were induced when cultured on MS medium supplemented with BA and/or BA plus NAA. Both apical shoot necrosis and hyperhydric shoots were observed frequently in multiplied shoots, and callus was formed at the basal part of shoots. About 20% spontaneous rooting was achieved in growing shoots, however the proliferated shoots exhibited poor rooting rate in gelrite supported media. When we tried to ex vitro rooting of the shoot cutting, the shoot cuttings rooted up to 50% with 100 mg/L IBA application. The rooted plantlets grew normally after acclimatization in the greenhouse.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1394-1398
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• 2007

Acaricidal activity of the active constituent derived from Pyrus ussuriensis fruits against Dermatophagoides farinae and D. pteronyssinus was examined and compared with that of the commercial benzyl benzoate. The $LD_{50}$ value of the ethyl acetate fraction obtained from the aqueous extract of P. ussuriensis fruits was 9.51 and $8.59{\mu}g/cm^3$ against D. farinae and D. pteronyssinus, respectively. The active constituent was identified as quinone by spectroscopic analyses. On the basis of $LD_{50}$ values with quinone and its congeners, the compound most toxic against D. farinae was quinone ($1.19{\mu}g/cm^3$), followed by quinaldine (1.46), benzyl benzoate (9.32), 4-quinolinol (86.55), quinine (89.16), and 2-quinolinol (91.13). Against D. pteronyssinus, these were quinone ($1.02{\mu}g/cm^3$), followed by quinaldine (1.29), benzyl benzoate (8.54), 4-quinolinol (78.63), quinine (82.33), and 2-quinolinol (86.24). These results indicate that the acaricidal activity of the aqueous extracts can be mostly attributed to quinone. Quinone was about 7.8 and 8.4 times more toxic than benzyl benzoate against D. farinae and D. pteronyssinus. Additionally, quinaldine was about 6.4 and 6.6 times more toxic than benzyl benzoate against D. farinae and D. pteronyssinus, respectively. Furthermore, the skin color of the dust mites was changed from colorless-transparent to dark brown-black by the treatment of quinone. These results indicate that quinone can be very useful as potential control agents, lead compounds, or the indicator of house dust mites.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.444-450
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• 2009

Amplified fragment length polymorphism (AFLP) marker was utilized for evaluation of genetic diversity of 60 pear germplasms. Twenty selective AFLP primer pairs generated a total of 522 polymorphic amplification products. From UPGMA (unweighted pair-group method arithmetic average) cluster analysis by using polymorphic bands, the pear germplasms were divided into four clusters by similarity index of 0.691. The first cluster (I) included European pears belonging to Pyrus communis and wild species such as P. nivalis and P. cordata. The second cluster (II) included Ussurian pea pears belonging to P. betulaefolia and P. fauriei. The third cluster (III) included pea pears belonging to P. calleryana and P. koehnei. Most of germplasms belonging to P. pyrifolia and P. ussuriensis, and interspecific hybrids were included in the fourth (IV) cluster. Therefore pear germplasms originated from East Asia were closely related to P. pyrifolia and P. ussuriensis. Similarity values among the tested pear germplasms ranged from 0.584 to 0.879, and the average similarity value was 0.686.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.290-297
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• 2015

Based on the place of its origin, pear tree (Pyrus spp.) is largely divided into European pears (P. communis, cultivated mainly in Europe and the U.S.) and Asian pears (P. pyrifolia, P. bretschneideri, and P. ussuriensis, distributed and grown in East Asian countries including China, Japan, and Korea). Most pear trees have 17 chromosomes (diploidy, 2n=2x=34). Their genetic studies and precise cultivar breeding are highly restricted by conditions such as self-incompatibility controlled by S-locus and juvenility as one major character of fruit crops. Genetic studies on Pyrus have been promoted by the development of various molecular markers. These markers are being utilized actively in various genetic studies, including genetic relationship analysis, genetic mapping, and QTL analysis. In addition, research on pear genetic linkage maps has been extended to studies for the identification of QTL for target traits such as disease resistance and genetic loci of useful traits. NGS technology has radically reduced sequencing expenses based on massive parallel reactions to enable high-capacity and high-efficiency. NGS based genome analyses have been completed for Chinese pear 'Danshansuli' and European pear 'Bartlett'. In Korea, GWAS for agricultural valuable traits such as floral structure, ripening, and total soluble contents have been conducted through resequencing. GBS has been performed for 'Whangkeumbae', 'Cheongsilri', and 'Minibae'.

• Journal of Plant Biotechnology
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• v.43 no.4
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• pp.466-472
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• 2016

This study analyzed the genetic diversity of 115 pear germplasms using 15 SSR markers. Three to forty-one SSR alleles were detected for each locus with an average of 16 alleles per locus. The average availability of markers was 0.966. The average observed heterozygosity ($H_{obs}$) was 0.603 (range: 0.140 to 0.929). The average expected heterozygosity ($H_{exp}$) was 0.718 (range: 0.463 to 0.904). The average polymorphism information content (PIC) was 0.692 (range: 0.403 to 0.897). The genetic relationships of pear germplasms were classified into two major groups by geographic origins and genetic characteristics according to genetic distance. The first group was composed of European pear belonging to Pyrus communis. The second group consisted of P. pyrifolia, P. ussuriensis, P. bretschneideri, P. betulaefolia, P. calleryana, interspecific hybrids, and unclear germplasms. The results of this study suggest that genotype analysis of pear germplasms using SSR markers can identify the genetic diversity of germplasms, and can be used to provide basic information for pear breeding.

• Korean Journal of Plant Resources
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• v.16 no.2
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• pp.99-108
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• 2003

This study was carried out to make a standard criteria for protection and maintenance of the big and old trees in Ansung city, Kyonggi Prvince. There have been found 6 vegetative species cultivated in this area, which are Zelkova serrata, Gingko biloba, Kalopanax pictus, Pyrus ussuriensis var. macrostipes, Pyrus ussuriensis var. acidula, Pinus densiflora, etc. The Zelkova serrata tree is the major species among them and about 73.5％ in the population of the big and old trees in this area. The DBH (diameter at brest height) of them is 1.5-1.9m in 29.4% of whole population and the tree height is 10-l4m in 47.1%. The estimate age of 7 trees is more than 500 years old and they were 20.6％ of the whole population. Interesting point is that about 64.7％ of these trees in this area have own succeed story in terms of folk religion, object of worship, taboo, legend or secret. This study has also revealed that many fowls, small animals and epiphyte inhabited with the big and old trees have been found. However, 97.1％ of them are in danger from the plant disease and noxious insects or cutting damage of branches, but no management has been taken. More over, 85.3％ of the whole investigated big and old trees have been in the poor condition for percolation or aeration because the area around them has been payed with asphalt or concrete.