• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.317-323
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• 2012

For the establishment of an efficient embryogenesis from microspore culture in Brassica napus L. domestic cultivar 'Tammiyuchae', four different factors affecting microspore embryogenesis and plantlet regeneration were investigated. The highest embryogenesis rate was achieved when microspores at late uninucleate to early binucleate stage were isolated from flower buds with a length of 3.0~3.5 mm. On average, 388 embryos generated from 1 ml of microspores media. The highest number of embryos was obtained when microspores were subjected to $32.5^{\circ}C$ for 2 days. Embryogenesis of 'Tammiyuchae' was increased with increasing microspore culture density up to about $5{\times}10^4ea/mL$. Gradually higher culture density repressed embryogenesis of microspores. Regeneration rate of shoots from microspore-derived embryos was observed in MS solid medium supplemented with $0.5mg{\cdot}L^{-1}$ NAA and $1.0mg{\cdot}L^{-1}$ BA, and grew well in MS solid medium without plant growth regulators.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.385-389
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• 2006

This study was carried out to determine the effect of raising seedling at Hallasan area of sub-alpine (altitude of 600m above sea level) to improve fruiting.ate of Squash (Cucurbita maxima) in retarding culture. 'Ebis' cultivar was seeded in plug tray of 32 cells and the seedlings were grown for 25 days. They were transplanted on August 26, 2004, following L-stem training method under rain-shielding condition. Seedling height, number of nodes and leaf area were higher in lowland than in sub-alpine area. T/R ratio of seedling in sub-alpine was much lower as compared with that in the lowland. The first fruiting was on the 19th node in sub-alpine area, and on the 26th node in the lowland area(control). The succeeding fruiting nodes were lower by 3 to 5 node than those of control. Fruiting rate of second flower was improved by 17.2% compared with the 1.4% in control. The marketable yield was increased by 27% by raising seedling in sub-alpine area (4,460 kg/10a). This also brought out 20% labour saving effect. The environmental condition for raising seedling in the sub-alpine area of Hallasan was effective for the improvement of Squash (Cucurbita maxima) fruiting rate compared with lowland area.

• Korean journal of applied entomology
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• v.51 no.2
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• pp.83-90
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• 2012

The effect of natural enemies on four major pests of hot pepper was tested in greenhouses. The aphids were successfully controlled by introducing three Aphidius colemani-banker plants, and releasing 23.3 wasps per $m^2$ on April 16 and 23 wasps per $m^2$ in a greenhouse of 660 $m^2$. To control thrips, Orius laevigatus was released twice, 3.0 bugs per $m^2$ at a time(May $11^{th}$ and June $12^{th}$). The thrips population was controlled within 0.3 thrips per flower during the growing season. To control two species of mites, Tetranychus kanzawai and Polyphagotarsonemus latus, and the silverleaf whitefly, Bemisia tabaci, a total of 113.7 individuals of Amblyseius swirskii were released twice(May $11^{th}$ and $30^{th}$). The densities of B. tabaci and T. kanzawai were kept within 171.0 individuals/trap and 0.8 individual/leaf, respectively. P. latus was suppressed completely twelve days after release. The cost of the released natural enemies to control the four arthropod pests in this study was 420,000 Won per 660 $m^2$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.189-195
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• 2012

To predict the blooming date of 'Yumyeong' peach trees, the models for flower bud developmental rate (DVR) were constructed. The DVRs were calculated from the demanded times at controlled air temperatures. The branches of 'Yumyeong' peach trees were incubated at three different temperatures of 9.7, 15.2, and $18.9^{\circ}C$. The DVRs were also constructed with blooming dates and air temperatures in the field, collected from 1979 to 2008 at the experimental orchard of National Institute of Horticultural and Herbal Science, Suwon, Korea. All the DVRs increased linearly or exponentially with air temperature. The DVR equations evaluated under controlled air temperatures were y=0.0018x+0.0051 and y=$0.0125e^{0.0603x}$. The DVR equations under field conditions were calculated as y=0.0039x-0.0112 and y=$0.0062e^{0.1512x}$. These DVR equations offer developmental indices and predict the date for blooming with air temperature data. These DVR equations were validated against the blooming data observed in the field. When the blooming dates were calculated with exponential DVR equations and daily air temperature data, the root mean squared errors between the observed and predicted dates were around 2 days. These results suggest that the DVR models are useful to predict the blooming date of 'Yumyeong' peach trees.

• Korean Journal of Breeding Science
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• v.43 no.3
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• pp.177-179
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• 2011

A new soybean cultivar 'Daewang' was released by Agricultural Research & Extension Services, Gangwon Province in 2008. The Goals of breeding the variety was for large seed size, high yield, lodging tolerance and resistance to diseases such as soybean mosaic virus (SMV) and bacterial pustule. 'Daewang' was derived from the cross of GWS91, which has yellow seed coat, large seed size and late maturity, and 'Seokryang-putkong', which has large seed size and early maturity. The preliminary, advanced and regional yield trials for evaluation and selection were carried out from 2002 to 2007. It has a determinate growth habit with purple flower, yellow seed coat, yellow hilum and large seed weight (33.6 g per 100 seeds). The maturity date of 'Daewang' is 16 days later than the 'Taekwang'. It has a high content of total isoflavone ($1,851{\mu}g/g$). The average yield of 'Daewang' was 2.68 MT/ha in the regional yield trials (RYT) carried out in four locations in Gangwon province from 2004 to 2007 which was 4 percent higher than the check cultivar 'Taekwang'.

• Korean Journal of Breeding Science
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• v.43 no.3
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• pp.172-176
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• 2011

'Suan' is a new $F_1$ hybrid variety of rapeseed (Brassica napus L.) with early maturing and high oleic acid. This hybrid variety was bred by the cross between Mokpo-CGMS (male sterile line) and 8516-B-5-6-5-3 (restore line) for the production of bio-diesel and edible oil in 2006. 'Suan' has green and parted leaf, yellowish flower, and black seed coat. 'Suan' is more tolerant to lodging and stem rot compared to 'Sunmang', check variety. The ripening date of 'Suan' is June 2nd which is 6 days earlier than 'Sunmang'. Yield trials were conducted from 2006 to 2007 and regional adaptation trials were examined at five locations each in 2008 and 2009. The average seed yield of regional adaptation trials was 381 kg/10a that was 4% higher than that of 'Sunmang'. Total oil content of 'Suan' was 44.3%. Oleic acid content was 68.3%, which is 5.2% higher than 'Sunmang' but, erucic acid was not detected. Total glucosinolate content was 2.31 mg/g. Therefore, this variety is recommended as a leading variety at southwestern area including Jeonnam, Jeonbuk and Kyongnam provinces of South Korea.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.565-573
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• 2010

Thinning of apple fruitlets is one of the most laborious and important works for the improvement of fruit quality and for the promotion of sufficient flower bud formation to prevent alternate bearing in commercial cultivars. Lateral fruits of self-thinning apple cultivars fall naturally within 30 days after full bloom and only central fruit remains to mature. Differences of gene expression between central fruit and lateral fruit were investigated by differential display (DD) PCR. Partial cDNAs of 30 clones from the central fruit and 24 clones from the lateral fruit were selected for nucleotide sequence determination and homology searches. The levels of transcripts coding for proteins involved in pathogenesis related proteins, senescence, temperature stress, protein degradation, fruit browning, sorbitol metabolism were significantly higher in pedicels of lateral fruit than in pedicels of central fruit. On the other hand, the up-regulation of proteins involved in anthocyanin and flavanol biosynthesis and ethylene synthesis were observed in pedicels of central fruit. In Real time PCR analysis, cytochrome P450 gene was confirmed as showing a higher expression level in lateral fruit than in central fruit. The results of this study indicate that differentially expressed genes are related to self-thinning characteristics in apple tree.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.2
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• pp.28-38
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• 2011

Dwelling reflects the continuance and change that, in general, expresses the era's cultural and social values. The yard of Korean traditional dwelling, although it is an exterior space, it is a companion space that is engaged with the main house. It operates many housing functions that were not achieved within the interior space. After the time of enlightenment, shape, function and the meaning of Korean traditional house yard along with the change of values and major living style has been changing. Therefore, to understand how the Chosun Dynasty's house yard is being used in modern days, this study is based on the research of 47 sites and conducted a study regarding the acculturation and division the house yards. Typical elements in the target garden site that are expressed in a way differentiated from the original form of the Korean traditional house yard were the materials and methods of planting, the use of garden ornaments, paving materials, the use of water, and changes in kitchen gardens. As the role of house yards changes, the modern division of the style of gardens occurred; the areas in a garden have been divided and the form of a garden has been differentiated according to the limit and initiative. The pursuit of ornamentality and practicality led to the differentiation of gardens' functions, while seeking after convenience resulted in the division of gardens' materials. The use of gardens has also been differentiated by adding commerciality and a concept of open garden in both symbolic and daily manners.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.34-39
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• 2023

Growth modeling in plant factories can not only control stable production and yield, but also control environmental conditions by considering the relationship between environmental factors and plant growth rate. In this study, using the expolinear function, we modeled perilla [Perilla frutescens (L.) Britt.] cultivated in a plant factory. Perilla growth was investigated 12 times until flower bud differentiation occurred after planting under light intensity, photoperiod, and the ratio of mixed light conditions of 130 μmol·m^-2·s^-1, 12/12 h, red:green:blue (7:1:2), respectively. Additionally, modeling was performed to predict dry and fresh weights using the expolinear function. Fresh and dry weights were strongly positively correlated (r = 0.996). Except for dry weight, fresh weight showed a high positive correlation with leaf area, followed by plant height, number of leaves, number of nodes, leaf length, and leaf width. When the number of days after transplanting, leaf area, and plant height were used as independent variables for growth prediction, leaf area was found to be an appropriate independent variable for growth prediction. However, additional destructive or non-destructive methods for predicting growth should be considered. In this study, we created a growth model formula to predict perilla growth in plant factories.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.302-310
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• 2023

In this study, the extent of the impact of rainfall on the outbreak of fire blight during the blossom infection risk period was explored. In the Chungnam province, the outbreak of fire blight disease began in 2015, and changes in the outbreak's scale were most pronounced between 2020 and 2022, significantly escalating from 63 orchards in 2020 to 170 orchards in 2021, before decreasing to 46 orchards in 2022. In 2022, the number of incidence has decreased and the number of canker symptom in branches has also decreased. It was evaluated that the significant decrease of fire blight disease in 2022 was due to the dry weather during the flowering season. In other words, this yearly fluctuation in fire blight outbreaks was correlated with the presence or absence of rainfall and accumulated precipitation during the blossom infection risk period. This trend was observed across all surveyed regions where apples and pears were cultivated. Among the weather conditions influencing the blossom infection risk period, rainfall notably affected the activation of pathogens from over-wintering cankers and flower infections. In particular, precipitation during the initial 3 days of the blossom infection risk warning was confirmed as a decisive factor in determining the outbreak's scale.