• Journal of Biosystems Engineering
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• v.26 no.5
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• pp.461-468
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• 2001

Impact between fruits and other materials is a major cause of product damage in harvesting and handling systems. The oriental pears are more susceptible to bruising than other fruits such as European pears and apples, and are required more careful handling. The interest in the handling of the pears for the processing systems has raised the question of the allowable drop height to which pears can be dropped without causing objectionable damage. Drop tests on pears were conducted using an impact device developed by authors to estimate the allowable drop height without bruising. The impact device was constructed to hold in a selected orientation and to release a fruit by vacuum for dropping on to a force transducer. The drop height was adjustable for zero to 60 cm to achieve the desired distance between the bottom of the fruits and the top of the impact force transducer. The transducer was secured to 150 kg$\sub$f/ concrete block. The transducer signal was sampled every 0.17 ms with a strain gage measurement board in the micro computer where it was digitaly stored for later analysis. The selected sample fruit was Niitaka cultivar of pears which is one of the most promising fruit for export in Korea. The pears were harvested during the 1998 harvest season from an orchard in Daejeon. The sample fruit was selected from two groups which were stored for 3 months and 5 months respectively by the method of current commercial practice. The pears were allowed to stabilize at environmental condition(18$^{\circ}C$, 65% rh) of the experimental room. One hundred fifty six pears were tested from the heights of 5, 7.5. 10 and 12.5 cm while measurement were made of impact peak force, contact time, time to peak force, dwell time, pear diameter and mass. The bioyield strength and modulus of elasticity were measured using UTM immediately after each drop test. The allowable drop height was estimated on the base of bioyield strength of the pears in two ways. One was assumed the peak force during impact test increasing linearly with time, and the other was based on the actual drop test results. The computer program was developed for measuring the impact characteristics of the pears and analyzing the data obtained in the study. The peak force increased while contact times decreased with increasing drop height and contact times of the sample from the hard tissue group. The allowable drop height increased with increasing bioyield strength and contact times, and also varied with Poisson\`s ratio, mass and equilibrium radius of the pears. The allowable drop height calculated by a theoretical method was in the range from 1 to 4 cm, meanwhile, the estimated drop height considering the result of the impact test was in the range from 1 to 6 cm. Since the physical properties of fruits affected significantly the allowable drop height, the physical properties of the fruits should be considered when estimating the allowable drop height.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.3
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• pp.94-101
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• 2008

Warming trends during winter seasons in East Asian regions are expected to accelerate in the future according to the climate projection by the Inter-governmental Panel on Climate Change (IPCC). Warmer winters may affect short-term cold hardiness of deciduous fruit trees, and yet phenological observations are scant compared to long-term climate records in the regions. Dormancy depth, which can be estimated by daily temperature, is expected to serve as a reasonable proxy for physiological tolerance of flowering buds to low temperature in winter. In order to delineate the geographical pattern of short-term cold hardiness in grapevines, a selected dormancy depth model was parameterized for "Campbell Early", the major cultivar in South Korea. Gridded data sets of daily maximum and minimum temperature with a 270m cell spacing ("High Definition Digital Temperature Map", HDDTM) were prepared for the current climatological normal year (1971-2000) based on observations at the 56 Korea Meteorological Administration (KMA) stations and a geospatial interpolation scheme for correcting land surface effects (e.g., land use, topography, and site elevation). To generate relevant datasets for climatological normal years in the future, we combined a 25km-resolution, 2011-2100 temperature projection dataset covering South Korea (under the auspices of the IPCC-SRES A2 scenario) with the 1971-2000 HD-DTM. The dormancy depth model was run with the gridded datasets to estimate geographical pattern of change in the cold-hardiness period (the number of days between endo- and forced dormancy release) across South Korea for the normal years (1971-2000, 2011-2040, 2041-2070, and 2071-2100). Results showed that the cold-hardiness zone with 60 days or longer cold-tolerant period would diminish from 58% of the total land area of South Korea in 1971-2000 to 40% in 2011-2040, 14% in 2041-2070, and less than 3% in 2071-2100. This method can be applied to other deciduous fruit trees for delineating geographical shift of cold-hardiness zone under the projected climate change in the future, thereby providing valuable information for adaptation strategy in fruit industry.

• Korean Journal of Medicinal Crop Science
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• v.23 no.4
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• pp.292-297
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• 2015

This study was carried out to have the basic and applied informations relating to develop the cultivation methods and to increase the productivity and quality of ginseng. 1 to 6 year old ginsengs of Jakyung cultivar were cultivated and the content and synthetic amount of carbohydrates were investigated with different plant tissues, growth stages, and years old. The concentration of total carbohydrates at six year old ginseng including water soluble and water insoluble carbohydrates was about 18.9%, 42.9%, and 43,6% in leaves, tap roots, and lateral roots, respectively. Water soluble carbohydrate of tap and lateral roots was slightly decreased from August until September, and then increased on November, whereas its water insoluble carbohydrate was increased from August to September and then decreased on November. Comparing with the content of carbohydrates of 1 to 6 year old ginsengs, it was continuously increased from one year old ginseng until five year old ginseng, however it was not increased much in six year old ginseng. The highest content of carbohydrates was at five year-old in all tissues of ginseng. Water soluble and water insoluble carbohydrates were significantly shown different in leaves, stems, tap roots, and lateral root at different growth stages and with different years old. The content of water soluble carbohydrate in the leaves was remarkedly higher compared to that of water insoluble carbohydrate, while in the root the content of water insoluble carbohydrate was clearly higher compared to the water soluble carbohydrate. Comparing with the synthetic amount of carbohydrates, water soluble carbohydrates was higher in the shoot than that in the root, whereas water-insoluble carbohydrates higher in the root than that in the shoot. Carbohydrates which would be utilized in ginseng tissues for short and long-term periods as major energy were appeared differently in between shoot and root, with different growth stages, and years old.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.57-63
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• 2012

This study was carried our to examine the genetic relationship of 13 commercial turfgrass cultivars using Random Amplified Polymorphic DNA to provide genetic informations more efficient golf course management. Analysis of 56 random hexamer primers generated 13 to 54 polymorphic bands among the 13 cultivars with an average of 30.7 bands per primer. The results of cluster analysis based on RAPDs revealed that three major variety groups: Group I - 'Shadow II', 'Aurora Gold', 'Little Bighorn Blue', 'PennA-1', and 'PennA-4'; Group II - 'Midnight II', 'Prosperity', 'Moon light SLT', 'Bright star SLT', and 'Silver dollar'; and Group III - 'Olympic Gold', 'Silver Star', and 'Tar Heel II'. The genetic similarity coefficients among 13 turfgrass cultivars ranged from 0.039 to 1.0 with highest coefficient in Group III. Studies on morphological characters and the effective molecular markers such as sequence characterized amplified regions are further needed to identify relationships and genetic diversities within species and among species.

• Journal of Plant Biotechnology
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• v.47 no.1
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• pp.78-89
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• 2020

Tomato fruit quality is determined by the contents of various functional metabolites in addition to fruit appearance. To develop tomato cultivars with higher amounts of functional compounds, an efficient quantification method is required to identify the natural variations in the compounds in the tomato germplasm. In this study, we investigated tomato varieties, which included 23 inbred lines and 12 commercial F₁ cultivars, for their contents of seven watersoluble vitamins (vitamin C, vitamins B1, B2, B3, B5, B6, and B9) and five polyphenolic compounds (quercetin, rutin, kaempferol, myricetin, and naringenin chalcone). The results of high performance liquid chromatography and liquid chromatography-mass spectrometry showed that vitamin C and naringenin chalcone were the major water-soluble vitamins and polyphenolic compounds, respectively, and their abundance was highly variable depending on the cultivar. By contrast, the contents of vitamin B1, quercetin, and kaempferol were lowest among the cultivars. With regard to the relationship between metabolic compounds and fruit characteristics, a significant association was found in fruit size, indicating that cherry tomato varieties contain higher amounts of the compounds compared to large fresh-type varieties. However, no direct association was detected in fruit color, except for naringenin chalcone. The results of this study provide new insights on the quantification of metabolic compounds and the selection of breeding materials, which are prerequisites for the development of functional tomato varieties.

• Journal of agriculture & life science
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• v.44 no.5
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• pp.81-90
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• 2010

This study was conducted to evaluate quality characteristics of citron from Namhae. The physicochemical properties, organic acid, free sugar and aroma components were analyzed and compared with citron harvested in different areas of Namhae (Seolcheon, Changseon and Idong-meyon). Total weight of citron was range of 120.51~176.56 g, total and peel weight of citron cultivated from Changseon were significantly higher than the other citron. The color of peel was not significant in cultivated area. Soluble solids was higher in citron from Changseon and Idong than Seolcheon. Total phenol and flavonoids contents in citron from Idong were higher than the others. Organic acids such as citric acid and malic acid were higher in citron from Changseon. The contents of fructose and glucose in peel and sucrose in pulp were detected higher amount. Major component of aroma profiles in citron from different region of was dl-limonene. It was amount to 57.60% in citron from Idong, 71.02% and 73.04% in citron from Seolcheon and Changseon of all aromatic components. These results were suggested that physicochemical properties and aroma components of citron have some difference by cultivation habit, period, different cultivar and producing areas.

• Genes and Genomics
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• v.40 no.12
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• pp.1319-1329
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• 2018

SSRs were successfully isolated from the Perilla crop in our current study, and used to analyze Perilla accessions from East Asia. Analyses of the clear genetic diversity and relationship for Perilla crop still remain insufficient. In this study, 40 new simple sequence repeat (SSR) primer sets were developed from RNA sequences using transcriptome analysis. These new SSR markers were applied to analyze the diversity, relationships, and population structure among 35 accessions of the two cultivated types of Perilla crop and their weedy types. A total of 220 alleles were identified at all loci, with an average of 5.5 alleles per locus and a range between 2 and 10 alleles per locus. The MAF (major allele frequency) per locus varied from 0.229 to 0.943, with an average of 0.466. The average polymorphic information content (PIC) value was 0.603, ranging from 0.102 to 0.837. The genetic diversity (GD) ranged from 0.108 to 0.854, with an average of 0.654. Based on population structure analysis, all accessions were divided into three groups: Group I, Group II and the admixed group. This study demonstrated the utility of new SSR analysis for the study of genetic diversity and population structure among 35 Perilla accessions. The GD of each locus for accessions of cultivated var. frutescens, weedy var. frutescens, cultivated var. crispa, and weedy var. crispa were 0.415, 0.606, 0.308, and 0.480, respectively. Both weedy accessions exhibited higher GD and PIC values than their cultivated types in East Asia. The new SSR primers of Perilla species reported in this study may provide potential genetic markers for population genetics to enhance our understanding of the genetic diversity, genetic relationship and population structure of the cultivated and weedy types of P. frutescens in East Asia. In addition, new Perilla SSR primers developed from RNA-seq can be used in the future for cultivar identification, conservation of Perilla germplasm resources, genome mapping and tagging of important genes/QTLs for Perilla breeding programs.

• Korean Journal of Breeding Science
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• v.40 no.1
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• pp.39-47
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• 2008

The 1,874 rice lines were selected from 3,000 Ds insertional mutant pool by Basta herbicide treatment and were surveyed for trait variation and molecular characteristics of genes knocked out by Ds insertion. Compared with "Donjin", an original japonica cultivar used for transformation, Ds insertion mutant pool showed large variation in major agronomic traits including tiller, panicle, and heading etc. Southern blot analysis demonstrated that these lines on the average had two Ds copies in Donjin genome, resulting in 38.4% of one copy, 32.5% of two copies, 16.7% of three copies, and 11.3% of over four copies. GUS analysis showed that 3.9% of lines (73/1,860) had tissue-specific expression in leaves, nodal parts, floral organs such as stigma and pollen, and roots. Data set obtained from agricultural trait variation and molecular characteristics for individual Ds insertional lines would provide researchers with more information for understanding the function of unknown rice genes controlling economically important traits.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.154-157
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• 2009

Pear has a gametophytic self-incompatibility (SI) system and its SI reaction is controlled by a single multi-allelic S-locus. 'Wonkyo Na-jasoojung 2' was selected from a cross between 'Wonwhang', early season major pear cultivar with high fruit quality and self-incompatible, and 92-18-79 (${S_4}^{sm}{S_4}^{sm}$) obtained from self cross of 'Osa-nijisseiki' (${S_2S_4}^{sm}$) (SM, stylar-part mutant), self-compatible bud mutant that originated from self-incompatible 'Nijisseiki' ($S_2S_4$) made in 2001 at the National Institute of Horticultural and Herbal Science, Rural Development Administration in Korea. '92-18-79' was selected as a self-compatible source through field investigation. It bloomed 1 day earlier than 'Osa-Nijisseiki' and similar to 'Wonwhang' in 2008. It is medium in tree vigor and spreading in tree habit. 'Wonkyo Na-jasoojung 2' is classified as highly susceptible to pear scab (Venturia nashicola) similar to 'Osa-Nijisseiki' and as resistant to black spot (Alternaria kikuchiana) similar to 'Wonwhang'. It had 65.7% fruiting rate by self pollination. The average optimum harvest time of 'Wonkyo Na-jasoojung 2' was 148 days after full bloom and it matured 2 days earlier than 'Osa-Nijisseiki' and 11 days later than 'Wonwhang'. The fruit is roundish oblate in shape and yellowish brown in skin color. Average fruit weight was 445 g and soluble solids content was 13.3 $^{\circ}Brix$. The flesh had abundant juice and negligible grit.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.488-495
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• 2009

In recent years, an increasing amount of research has been conducted on the yield loss of soybean crop caused by Riptortus clavatus, a serious pest of legumes. The objective of this study were to examine crop damage caused by various population densities of R. clavatus and determine the association of unique growth and seed characteristics with crop damage rate in conventional soybean fields. Major growth responses to R. clavatus were examined. The cultivars that were not as seriously damaged by R. clavatus were Pungsannamulkong, Sobaegknamulkong, Duyoukong, and Sinpaldal 2, but Myeongjunamulkong, Mallikong, and Hwangkeumkong were significantly (P<0.05) damaged. The rate of seed damage caused by R. clavatus was 8.2% in a group of brown colored pubescence, while the rate was 13.0% in a group of the gray colored. Crop damage by R. clavatus clearly more reduced in cultivars with dark hilum colors including dark brown, brown, and grayish brown than those with yellow hilum colors. Concerning pod colors, crop damage was less significant in cultivars with dark brown pod color than with the light brown. Cultivars with short pod length (4.0-4.5 cm) at full seed (R6) stage showed lower seed damage rates by R. clavatus than those with long pod length (>5.6 cm). Therefore, characteristics of hilum, pod, pubescence colors, and pod length were significantly related and linked to the cultivar resistance to R. clavatus.