In 2005, a new persimmon ( Diospyros kaki L. Thunb.) cultivar ‘Wonchu’ was derived by crossing ‘Shinsyu’ and ‘Taishu’, and it was finally selected in 2015. In the Yeoung-am province, the average maturing date of the fruit of this cultivar was October 3 rd . The quantitative characteristics of the fruit of ‘Wonchu’ include a larger size (324 g on average) and presence of high soluble-solids (approximately 15.1 °Brix). The flesh of the fruit is juicy, has a crispy texture, and tastes good. The shape of the fruit is round oblate (when looked from the side), and the color of its skin is orange. Physiological disorders, such as fruit cracking or fine skin cracking, rarely occur (Registration No. 8579).

Background: Persimmon (Diospyros kaki Thunb.) is the most widely cultivated species of the genus Diospyros. In this study, genetic diversity and variations in persimmon genotypes were investigated using single nucleotide polymorphism (SNP) markers identified by genotyping-by-sequencing (GBS) analysis. Results: Ninety-five persimmon accessions grown in the Pear Research Institute, National Institute Horticultural and Herbal Science, were sequenced using the Illumina Hiseq2500 platform and polymorphic SNPs were detected to develop molecular markers. These reliable SNPs were analyzed using the Kompetitive Allele Specific PCR (KASP) assay to discriminate among persimmon genotypes. GBS generated a total of 447,495,724 trimmed reads, of which 89.7% were raw reads. After demultiplexing and sequence quality trimming, 108,876,644 clean reads were mapped to the reference transcriptome. An average of 1,146,070 genotype reads were mapped. Filtering of raw SNPs in each sample led to selection of a total of 1,725,401 high-quality SNPs. The number of homozygous and heterozygous SNPs ranged from 1,933 to 6,834 and from 846 to 5,927, respectively. Conclusions: Of the 49 SNPs selected for development of an identification system for persimmons, 15 SNPs were used in the KASP assay to analyze 32 persimmon accessions. These KASP markers discriminated among all accessions. How to cite: Ma KB, Yang SJ, Jo YS, et al. Development of Kompetitive Allele Specific PCR markers for identification of persimmon varieties using genotyping-by-sequencing. (C) 2020 Pontificia Universidad Catolica de Valparaiso. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

A new persimmon (Diospyros kaki L. Thunb.)cultivar, 'Gampung', a progeny derived from the cross between 'Daeandangam' and 'Taishu' in 2004, was finally selected in 2013.Fruits of 'Gampung' were available for harvest on October 24 in the Yeong-am area.It had a very large fruit size of 413 g on average, and high soluble solids of approximately 14.7 °Bx.Its flesh taste was good, and it had a crispy texture and rich juice.The shape of the fruit was round oblate from the side view, and it had orange skin.Physiological disorders such as fruit cracking or skin fine cracking rarely occurred in this cultivar (Registration No. 8030).

This study was to prepare the pear-dried fruit for revitalizing the pear fruit industry, measuring the fruit quality characteristics and antioxidant activity according to different drying methods for both normal and physiological disorder fruit. The moisture content was significantly decreased with the lower in drying temperature. The L* value of freeze-drying, while a* and b* value were hot-air and vacuum drying were the greatest, leading to slight browning with yellow color. The soluble sugar content had the highest sucrose content in hot-air and freeze-drying, and fructose was found highest in vacuum drying. The total polyphenol content was found to decrease with increasing drying temperature, but the total flavonoid content did not differ according to the drying method. Four phenolic compounds were detected, namely, arbutin, catechin, chlorogenic acid, and gallic acid; fruits dried using hot-air drying had greater contents of these compounds than fruit treated with the other drying methods. Although there was no difference in the quality of dried fruit production using physiological disorder fruit, it would have to be used as a component of processed food as the area of disorder part was clearly brown. Also, because the effects on colors, ingredients, and texture vary depending on the drying method, which can be used to produce dried fruits that can be stored for a long period of time.

In 2014, a new high-quality, pollination-constant, non-astringent persimmon (Diospyros kaki L. Thunb.) cultivar, ‘Wonmi’, a breeding of ‘Fuyu’ and ‘Taishu’ from 2005, was developed. ‘Wonmi’ fruit were harvested on October 8 in Yeongam, South Korea. The fruit are medium-sized (220 g on average), with a high amount of soluble solids (15.1 o Bx). The juicy flesh has a pleasant taste and crispy texture. The fruit shape is round oblate, and the skin color is orange with a graceful appearance. Physiological disorders, such as stylar-end or fine skin cracking, rarely occur in this cultivar (Registration No. 7724).

The market of persimmon fruits in Australia is expanding in line with consumer's strong interest in functional healthy foods, increased immigrants from Asian countries and its exporting market expansion. However, it is hard to expect the Australia’s main sweet persimmon varieties, ‘Fuyu’ and ‘Jiro’, to meet the expanding market needs, due to their limited harvest period. Therefore, the Australia's persimmon growers want the new varieties with various harvest times, and are trying to introduce Korea-bred new sweet persimmon varieties, such as ‘Fantasy’, ‘Gampung’, ‘Wonmi’ and ‘Wonchu’. Presently, ‘Fantasy’ and ‘Gampung’ have obtained patents for cultivar protection in Australia, and their local adaptability test is underway. ‘Wonmi’ and ‘Wonchu’ have also been applied for cultivar protection patent in Australia. In future, all these, due to their early and medium-maturity fruits and excellent quality, are expected to be the new key persimmon varieties in Australia.

This study was conducted to determine the optimal physiological ripening time and suggest a reasonable harvest time indicator by analyzing the relationship between change in physicochemical characteristics and the sugar composition change patterns during development of 'Hanareum' fruit from 54 days after full bloom (DAFB) to 130 DAFB. The weight of fruits from 96 to 115 DAFB rapidly increased and then became gentle showing a typical sigmoidal curve. Flesh hardness decreased steadily after 96 DAFB; there was no significant difference in flesh hardness for 115, 125 and 130 DAFB fruits. The starch content began to reduce around the core for 119 DAFB. Moreover, sucrose and fructose contents started to increase with fruit development; however, the sucrose content continuously increased, whereas the fructose content started to decrease for 110 DAFB. Fruits of 125 and 130 DAFB did not show coloration according to the iodine test. Based on these results, it was estimated that the optimal physiological ripening time of 'Hanareum' was between 119 and 125 DAFB. The results of correlation analysis between fruit development change and sugar composition change patterns of fruits of 'Hanareum' showed that there was a strong linear relationship. Correlation coefficient between the sucrose/fructose (S/F) ratio and flesh hardness is -0.57, between S/F ratio and iodine test results is 0.80. Namely, S/F ratio is possible to use for harvest time determination indicator and the point of S/F ratio of 0.9–1.1 was considered to be ideal for the determination of the optimal physiological ripening time at which starch completely degrades.

A persimmon (Diospyros kaki L. Thunb.) cultivar, ‘Chosi’, which was a cross between ‘Johongsi’ and ‘Nishimurawase’ in 2000, was finally selected in 2010. ‘Chosi’ persimmon fruits were harvested in Sept. 19 in Naju, with a medium fruit size of 161 g, on average, and high soluble solids of approximately 15.3 oBx. The flesh tastes good, with a crispy texture, and the juice is rich. The shape of the fruit is round oblate, and the skin color is orange; the appearance is graceful. Physiological disorders, such as stylar-end cracking or skin fine cracking, rarely occur in this cultivar. (Registration No. 7075)

Interspecific hybridization is a popular breeding method employed to introduce effective factors into crops. To evaluate the potential of this method to enrich the quality of pear fruits, we carried out crosses between P. pyrifolia and other species using the pollens of 'OPR114' and 'OPR260' of P. betulaefolia, 'Dangshansuli' , 'Xuehuali ' , and 'Yali' of P. bretschneideri, 'OPR125 ' , 'OPR195 ' , and 'OPR249' of P. calleryana, 'Bartlett', `Bose', 'Canal pear', and 'Max Red Bartlett' of P. communis, and 'Chuhwangbae' of P. pyrifolia to pollinate flowers of P. pyrifolia 'Niitaka'. Fruit set in 'Niitaka' pear after artificial pollination was investigated under both field and controlled conditions, which encompassed temperature control and use of water-cuttings of winter twigs. To assess compatibility of hybridizations, pollen tube elongation was analyzed in squashed styles under controlled temperature, and the self-incompatibility (SI) gene pattern was validated by PCR. Under field conditions, crosses of 'Niitaka' with 'OPR114' of P. betulaefolia and `Bose' and 'Canal pear' of P. communis resulted in incompatibility, as the fruit set was low. However, when 'Niitaka' was pollinated by 'Xuehuali', some of the pollen tubes reached the ovary but they then arrested and appeared swollen in the middle part of the style. PCR confirmed the incompatibility of these crosses, as the gene product from pollens was a different size from that of the 'Niitaka'. However, interspecific hybridization under controlled conditions resulted in fruit production. We show that interspecific hybridization with P. pyrifolia and other species was feasible under controlled conditions. Suggesting that self-incompatibility of crosses was dependent on environmental factors rather than genetic predisposition.

This was carried out to develop a chromosome-doubled (12x) persimmon that will be used as a crossing parent to select seedless persimmon cultivars with the change of the consumption trend recently. To obtain a chromosome-doubled (12x) persimmon, colchicine was applied at the meristem of seedlings in vitro derived from cross among hexaploid persimmon (Diopyros kaki Thunb.). These were treated with 0.03%, 0.05% and 0.1% colchicine respectively for doubling chromosome, and it was most effective at the concentration of 0.05% colchicine. After colchicine treatment, we conducted tests to elucidate conditions for inducing shoot and root development. As the result, the shoots grew best when cultivated at 1/2MS media plus 10 and 30 μM zeatin respectively, and the roots grew best when cultivated at 1/2MS media after dipping for 5 seconds at 10 mM NAA+5% DMSO. We also compared seedlings that have chromosome (6x) do not doubled and crossing parents (6x) and chromosome-doubled seedlings (12x). As the result, these chromosome-doubled seedlings (12x) showed lower stomatal density and larger stomatal size.

In 1994, a new cultivar ‘Joyskin’ was created from a cross between the cultivars ‘Whangkeumbae’ and ‘Waseaka’ at the Pear Research Institute of the National Institute of Horticultural and Herbal Science, Rural Development Administration. In 2006, the ‘Joyskin’ was selected from among the 317 seedlings resulting from the cross for its skin and taste qualities. Regional adaptation tests were conducted in nine regions and in ten experimental plots from 2006 to 2011. The cultivar was named in 2011. ‘Joyskin’ showed a vigorous growth habit and semi-spread characteristics similar to ‘Whangkeumbae’. The average full bloom date for ‘Joyskin’ was April 21st, which was also similar to ‘Whangkeumbae’. The optimum fruit ripening time was September 6-8th, which was six or eight days earlier than ‘Whangkeumbae’. The fruit was round in shape and the skin was a golden yellow color at maturity. The average fruit weight was 320 g and the flesh firmness was 2.5 kg/8mmφ. The firmness of the fruit skin determined by a blade-type plunger of texture analyzer was 22.9 N, which was significantly different from that of ‘Whangkeumbae’ 29.9N. Stone cell analysis of ‘Joyskin’ by phloroglucinol-HCl, showed that ‘Joyskin’ stone cells were small in size and few in numbers cpmpared to those of cultivars of was ‘Manpungbae’, ‘Niitaka’, and ‘Whangkeumbae’. The patent application for ‘Joyskin’ was submitted in April, 2012 (Grant No. 2012-337). In 2016, ‘Joyskin’ (Grant No. 5895) was registered as a separate record, with uniformity and stability per Korean Seed Industry Law. Additional key words: crossing breeding, fruit, Pyrus pyrifolia, self-incompatibility, stone cell

To develop scab-resistant pear (Pyrus spp.) varieties with fruits that are as crisp and juicy as Asian pears, a cross was made between ‘Whangkeumbae’ and ‘Bartlett’ varieties (P. pyrifolia × P. communis) at the Pear Research Institute of the National Institute of Horticultural & Herbal Science, Rural Development Administration, in 1994. Among the 285 seedlings, ‘Greensis’ was first selected in 2006 for its good eating quality and named in 2012 after regional adaptation tests in nine regions and ten experimental plots from 2007 to 2012. The tree showed a vigorous growth habit and semi-spreading characteristics, like ‘Whangkeumbae’. The optimum fruit harvest date was also around Sept. 26 and fruit was round in shape and green in skin color at maturity. Average fruit weight was 470g, and the soluble solids content was 12.4°Brix. The flesh was very crisp and juicy, and had good eating quality. Its’ leaf size was similar with ‘Bartlett’ and smaller than ‘Whangkeumbae’. The average of full bloom date of ‘Greensis’ was determined as Apr. 26, which was six days later than ‘Whangkeumbae’ and similar with ‘Bartlett’. S genotypes of ‘Greensis’ were identified as S4Se by S-allele PCR product sequencing analysis. It seems that the S4 allele was inherited from ‘Whangkeumbae’ and the Se allele from ‘Bartlett’. ‘Greensis’ displayed strong resistance to scab disease caused by Venturia nashicola , similar to European pear cultivars like ‘Beurre Hardy’ and, ‘Conference’. ‘Greensis’ was also highly resistant to black leaf spot (Alternaria kikuchiana) in the field