• Horticultural Science & Technology
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• v.31 no.6
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• pp.790-797
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• 2013

During pear fruit development, calyx can abscise from fruitlet following petal fall. The calyx abscission varies with pear cultivars. The presence of calyx on pear fruit makes the fruit shape calyx end protruded. In the present study, the degrees of the calyx abscission were examined in 120 Southern-type Asian pear (Pyrus pyrifolia), 52 Nothern-type Asian pear (P. ussuriensis), and 34 European pear (P. communis) cultivars, and its inheritance was investigated using cross combinations between the Southern-type Asian pear cultivars showing different degrees of calyx abscission. Majority of the cultivars produced < 10% or > 90% calyx-perpetual fruit, but the cultivars producing both calyx-perpetual and -deciduous fruit were in minor frequency. The cultivars producing < 10% calyx-perpetual fruit were in higher frequency in Southern-type Asian, Nothern-type Asian, and European pears in that order, while those producing calyx-perpetual fruit were in higher frequency in European, Nothern-type Asian, and Southern-type Asian pears in that order. In the cross between the parents producing < 10% calyx-perpetual fruit, most of the $F_1$ seedlings also produced < 10% calyx-perpetual fruit. In the cross between the parents producing > 90% calyx-perpetual fruit, on the contrary, most of the $F_1$ seedlings also produced > 90% calyx-perpetual fruit. When the paternal parent produced < 10% calyx-perpetual fruit, most of the $F_1$ seedlings also produced < 10% calyx-perpetual fruit regardless of the degree of calyx abscission in the maternal parent. When the cross was between the maternal parent producing < 10% calyx-perpetual fruit and the paternal parent showing different degrees of calyx abscission, the $F_1$ seedlings showed similar degrees of the calyx abscission to those in the paternal parent. These results suggest that the characteristics of the calyx abscission is influenced more greatly by the paternal parent than by the maternal parent, and the calyx abscission in Southern-type Asian pears is a qualitative trait which is governed by dominant gene(s).

• Horticultural Science & Technology
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• v.32 no.2
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• pp.193-201
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• 2014

We investigated the effect of preharvest spray of aminoethoxyvinylglycine (AVG) on the fruit quality and incidence of physiological disorders during shelf-life of 'Hanareum' and 'Wonhwang' pear (Pyrus pyrifolia Nakai). AVG applications (0, 75, 150 and $300mg{\cdot}L^{-1}$) made 30 days before anticipated harvest of respective cultivar. AVG did not influence the fruit development and quality parameters including starch content, soluble solids and acidity at harvest time in two pear cultivars although the flesh firmness of the fruits treated with $300mg{\cdot}L^{-1}$ AVG were higher than that of control in 'Hanareum' pear. Among the three AVG concentrations, only $300mg{\cdot}L^{-1}$ AVG showed effectiveness on maintaining flesh firmness in 'Hanareum' pear during shelf-life. Meanwhile, competitive high flesh firmness was attained in 'Wonhwang' pear treated with $150mg{\cdot}L^{-1}$ AVG (27.7 N) and $300mg{\cdot}L^{-1}$ AVG (28.2 N) when compared with untreated control (17.8 N) during 21 days of shelf-life at $25^{\circ}C$. AVG did not cause any significant difference at skin color development relative to control in two pear cultivars. AVG decreased ethylene production and respiration rate at $300mg{\cdot}L^{-1}$ level in two pear cultivars during the entire shelf-life. During shelf-life, low incidence of physiological disorders including internal and core browning and mealiness were attained in the fruits treated at $300mg{\cdot}L^{-1}$ AVG in two cultivars when we compared with the untreated control.

• Research in Plant Disease
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• v.8 no.4
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• pp.254-257
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• 2002

It was conducted to investigate an effective control measure of the black necrotic leaf spot disease on pear, The disease commonly occurred in major cultivation areas of Korea revealed 5.6 ％ infection rate on the widely growing cultivar Niikata. The disease substantially reduced yield and quality of pear fruits, however, it has never been controlled by chemicals. Renewal of the pear trees to resistant cultivar was found to be the most effective to control the disease. As a result, the disease did not developed for 2 years on the diseased Niikata that was top-grafted with resistant cultivars Soowhang and Whasan. lop-grafting with resistant cultivars was recommended far the pear trees showing over 80％ infection rate and lower than 70% fruit yield compare to standard production.

• Horticultural Science & Technology
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• v.34 no.3
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• pp.453-460
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• 2016

The parentage of the horticulturally important pear cultivar 'Niitaka' was confirmed by determining its S-genotypes based on the S-RNase and $PpSFBB^{-{\gamma}}$ genes, and genotyping using simple sequence repeat (SSR) markers. Previous reports suggested that the cultivars 'Amanogawa' and 'Imamuraaki' were the parents of 'Niitaka', although the cultivars 'Chojuro' and 'Shinchu' were also examined as candidate parents, along with two other cultivars. In the present study, the S-genotype of 'Niitaka' was determined to be $S^3S^9$. The $S^9$-RNase of 'Niitaka' was found to be likely inherited from the parent 'Amanogawa' ($S^1S^9$) and the $S^3$-RNase from 'Chojuro' ($S^3S^5$) or 'Shinchu' ($S^3S^5$). Based on the S-genotypes, the cultivar 'Imamuraaki' ($S^1S^6$) had no contribution to the parentage of 'Niitaka' ($S^3S^9$). A total of 67 polymorphic SSR markers were used to further confirm the parentage of 'Niitaka'. Discrepancies were found at several SSR loci between 'Niitaka' and the cultivars 'Imamuraaki' and 'Shinchu', whereas 'Niitaka' inherited alleles from 'Amanogawa' and 'Chojuro' at all SSR loci. Therefore, our findings established that 'Amanogawa' and 'Chojuro' are the parents of pear cultivar 'Niitaka', and not 'Imamuraaki' as previously reported.

• Journal of Plant Biotechnology
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• v.4 no.2
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• pp.45-52
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• 2002

A lot of SSRs (simple sequence repeats) in peach and pear from enriched genomic libraries and in peach from a cDNA library were developed. These SSRs were applied to other related species, giving phenograms of 52 Prunes and 60 pear accessions. Apple SSRs could also be successfully used in Pyrus spp. Thirteen morphological traits were characterized on the basis of the linkage map obtained from an $F_2$ population of peach. This map was compiled with those morphological markers and 83 DNA markers, including SSR markers used as anchor loci, to compare different peach maps. Molecular markers tightly linked to new root-knot nematode resistance genes were also found. A linkage map including disease related genes, pear scab resistance and black spot susceptibility, in the Japanese pear Kinchaku were constructed using 118 RAPD markers. Another linkage map, of the European pear Bartlett, was also constructed with 226 markers, including 49 SSRs from pear, apple, peach and cherry. Maps of other Japanese pear cultivars, i.e., Kousui and Housui, were also constructed. These maps were the first results of pear species.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.117-123
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• 2001

The occurrence and damage by the oriental fruit moth, Grapholita molesta (Busck) were investigated on pear trees from 1996 to 2000 in the Naju, Korea. The number of overwintering larvae in pear trees considerably varied depending on the maturation time of varieties. The density of overwintering larvae on late cultivars such as Gamcheonbae and Okusankichi was high, but relatively low on early cultivars. Trunk and main branch of pear trees were main overwintering sites. In 1997, overwintering larvae began to pupate from middle February, and to emerge from late March. Male moths were caught in the sex pheromone traps from late March until early October with four peaks of flight in 1996~2000. In every generation larvae damaged both the shoots and fruits of pear tree, but the first and second generation larvae tended to damage mainly shoots, while most of the injured fruits were due to the third and fourth generation larvae. In pear fruits damaged by fruit moths, most of these were caused by oriental fruit moth larvae and none of pear fruits were damaged by peach fruit moth or pear fruit moth larvae in 1998~2000.

• Research in Plant Disease
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• v.25 no.1
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• pp.43-47
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• 2019

Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), and Apple scar skin viroid (ASSVd) are economically important viruses that infect pear tree species worldwide. To evaluate the prevalence of these viruses in Korea, we investigated infection degree of three viruses and one viroid for the commercial nursery trees of the pear cultivars, Niitaka, Chuwhang, Wonwhang, and Whasan in 2017 and 2018. The results showed that the infection ratio of ACLSV, ASPV, ASGV, and ASSVd for the scion of pear cultivar Niitaka was 10%, 45%, 77%, and 50%, respectively. From the scion of pear cultivar Chuwhang, infection ratios of ASPV, ASGV, and ASSVd were found to be 70%, 50%, and 60%, respectively. From the scion of pear cultivar Whasan, infection ratios of ACLSV, ASPV, ASGV and ASSVd were found to be 40%, 60%, 93%, and 20%, respectively. From the root stock of pear cultivar Wonwhang, infection ratios of ACLSV, ASPV, ASGV, and ASSVd showed 28%, 57%, 100%, and 14%, respectively. ASGV had the highest recorded infection rate, and ACLSV was characterized by the lowest infection rate. The mixed infection ratio of Niitaka, Chuwhang, Whasan, and Wonwhang was 45%, 60%, 70%, and 85%, respectively.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.101-109
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• 2002

A lot of SSRs (simple sequence repeats) in peach and pear from enriched genomic libraries and in peach from a cDNA library were developed. These SSRs were applied to other related species, giving phenograms of 52 Prunus and 60 pear accessions. Apple SSRs could also be successfully used in Pyrus spp. Thirteen morphological traits were characterized on the basis of the linkage map obtained from an $F_2$ population of peach. This map was compiled with those morphological markers and 83 DNA markers, including SSR markers used as anchor loci, to compare different peach maps. Molecular markers tightly linked to new root-knot nematode resistance genes were also found. A linkage map including disease-related genes, pear scab resistance and black spot susceptibility, in the Japanese pear Kinchaku were constructed using 118 RAPD markers. Another linkage map, of the European pear Bartlett, was also constructed with 226 markers, including 49 SSRs from pear, apple, peach and chewy. Maps of other Japanese pear cultivars, i.e., Kousui and Housui, were also constructed. These maps were the first results of pear species.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.101-109
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• 2002

A lot of SSRs (simple sequence repeats) in peach and pear from enriched genomic libraries and in peach from a cDHA library were developed. These SSRs were applied to other related species, giving phenograms of 52 Prunus and 60 pear accessions. Apple SSRs could also be successfully used in Pyrus spp. Thirteen morphological traits were characterized on the basis of the linkage map obtained from an Fa population of peach. This map was compiled with those morphological markers and 83 DHA markers, including SSR markers used as anchor loci, to compare different peach maps. Molecular markers tightly linked to new root-knot nematode resistance genes were also found. A linkage map including disease-related genes, pear scab resistance and black spot susceptibility, in the Japanese pear Kinchaku were constructed using 118 RAPD markers. Another linkage map, of the European pear Bartlett, was also constructed with 226 markers, including 49 SSRs from pear, apple, peach and cherry. Maps of other Japanese pear cultivars, i.e., Kousui and Housui, were also constructed. These maps were the first results of pear species.

• Food Science and Preservation
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• v.23 no.2
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• pp.174-179
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• 2016

This study was to prepared vinegars using three kinds of pear cultivar with different maturities, 'Wonhwang', 'Niitaka', and 'Chuhwangbae', and investigate their physicochemical characteristics and antioxidant activities. Result showed that the firmness of 'Wonhwang' was much lower than other pear cultivars. No significant difference in soluble solid content was found among three pear cultivars. The total acidity of 'Chuhwangbae' pear vinegar was 4.89~7.98%, which was higher than that those of 'Wonhwang' and 'Niitaka' vinegars. The color of 'Niitaka' vinegar had a lower lightness and redness values, but a higher yellowness value, compared with the other two vinegars. The free sugar contents were mainly composed of fructose, glucose, and sorbitol, with the greatest content of sorbitol in all three peer vinegars. The total phenolics and flavonoids contents were 35.2~55.3 and 8.4~14.4 mg/100 mL, respectively. Antioxidant activity had a positive correlation with total phenolic contents. The DPPH free radical scavenging and $ABTS^+$ radical scavenging activity were 45.0~62.1% and 73.8~78.2%, respectively. From these results, we confirmed that immature pear cultivars such as 'Wonhwang', 'Niitaka' and 'Chuhwangbae' could be used as a raw materials to prepare vinegar regardless of maturity.