• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.276-280
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• 2012

This study was conducted to determine the ideal beginning date of plastic house optimum heating for off-season (December) production of asparagus. To achieve this, the 1.6-year-old 'Green tower' asparagus was cultivated in Jeju area ($33^{\circ}$28.110N, $126^{\circ}$31.076E) and the yield and quality among 7 different beginning dates of heating from Oct. 25 to Jan. 20 with 15-days interval were compared. The heating was controlled to maintain the inside temperature was higher than $20^{\circ}C$, But the plastic house was ventilated when the inside temperature rose to $30^{\circ}C$. Days to sprouting took longer as heating dates were delayed. Days to sprouting took 52 days in heating at December 30, and the days were shortened thereafter. As the beginning of heating was delayed, sprouting of asparagus was retarded. Among treatments, days to sprouting was 52 days and longest when the heating began on December 30. When the heating began on October 25, harvest was earliest and started on 7 November. When the heating began on November 15 and 30, harvest started on November 30 and December 18, respectively. Harvesting started on November 7 for October 25 heating, November 30 for Nov. 15 heating, and December 18 for November 30 heating, respectively. When the heating began was done after December. 15, harvesting was possible after early January. The number of spear, spear weight and yield were highly increased in the treatments of heating after January. 10 when the asparagus dormancy was broken. In the case of heating dates were before the asparagus dormancy breaking, the total yield was highest in November 15 heating with 607 kg/10a. The marketable yield of November 15 heating was 386kg/10a, which was twice higher than the 193 kg/10a of October 25 heating. Accordingly, it is recommended to start heating on November 15 for the production of off-season (December) asparagus in Jeju. Therefore, the optimum heating date to start was November 15 for the improvement of quality and yield of off-season (December) asparagus in Jeju area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.23-29
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• 1989

In order to investigate developmental habit and morphology of maize tillers, time and location of tiller development. number of tillers per plant, tiller angle, height and diameter of tillers and root systems of tillers were examined under field condition for maize with tillers. Materials used were mostly from Korean local lines and a few lines from other countries were also included for comparison. The time of the first tiller development was about 18 to 20 days after emergence when planted on May in Yusong. The second tiller appeared about 4 to 5 days after the first tiller appeared. The tiller number per plant varied with lines and hybrids and ranged from two to ten. The location of tiller development was usually basal nodes of the main stem. Each tiller appeared to have its own root system. The angle between tillers and main stem was variable depending upon the maizes and the tiller angle could be classified into three categories. The height of tillers was also variable and seemed to be under genetic control. The most productive tillers were found among the Korean local derivatives.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.30-39
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• 1989

Forage productivity of cropping systems of rye - silage corn, silage corn - oats, silage corn - rape was studied in the south-eastern part of Korea where rice black-streaked dwarf virus(RBSDV) infection of corn are severe. Rye(cv. Paldanghomil) was planted on Oct. 20 of 1986 and harvested 10 times from April 5 to May 5 at the 5-day intervals in 1987, corn (cv. Suweon 19 and Jinjuok) was planted 5 times from April 5 to May 15 at the 10-day intervals in 1987, and oats(cv. Megwiri) and rape (cv. Velox) were planted 4 times from Sept: 4 to 25 at the 7-day intervals and harvested 4 times from Nov. 10 to Dec. 10 at the 10-day intervals in 1987. Considering yield, nutrition value, and in vitro dry matter digestibility (IVDMD), forage productivity of the cropping systems was compared. As harvesting time of rye delayed, plant height, dry matter(DM) yield, percent DM, crude fiber, and digestible DM yield increased, but crude protein, crude fat, and IVDMD decreased. However, nitrogen free extract was not different among the harvesting dates. As planting date of corn delayed, RBSDV infection rate increased. but DM yield of silage decreased. However, silage yield of Jinjuok was higher, but RBSDV infection rate was lower compared with Suweon 19 at all planting dates. DM yield of oats and rape decreased as planting date delayed. However, at Sept. 4 and 11 plantings yield of oats on Nov. 10 was much lower than that of rape, but the differences in yield between two crops decreased with delayed harvesting, and yield was similar on Dec. 10. A cropping system harvesting rye around April 20 and followed by planting corn in late April was best among the rye-corn systems considering yield and nutrition value of both crops. However, among the corn-oats or corn-rape cropping systems early April planting of corn and followed by early Sept. planting of oats or rape showed best results with similar yield potential of the best rye-corn cropping system.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.22-29
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• 2011

The experiment investigated effect of duration, temperature, and light condition during chilling treatment on growth and flowering of four Campanula species in a factorial experiment. Two parent species, Campanula punctata Lam. var. rubriflora Mak. and C. Punctata Lam., and their two $F_1$ hybrids, C. punctata Lam. ${\times}$ C. punctata Lam. var. rubriflora Mak. ('Jiknyeo') and C. punctata Lam. var. rubriflora Mak. ${\times}$ C. punctata Lam. ('Gyeonu'), were used. Plants were cultured in vitro for five weeks at $25^{\circ}C$ under about $75{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD before being chilled at 4 or $25^{\circ}C$ for 3, 6, or 9 weeks under a darkened or lighted (about $10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD) condition. After chilling treatment, plants were transplanted to 10 cm pots filled with a commercial growing medium and were transferred to environment-controlled growth chambers and subsequently to a greenhouse to observe their reproductive growth. Growth of all species and flowering of a $F_1$ hybrid 'Jiknyeo' were affected by duration, temperature, and light condition during chilling treatment. The greatest growth and survival percentage were observed in C. punctata Lam. var. rubriflora Mak. The survival percentage was greater when plants were chilled in a lighted than darkened condition, whereas it decreased when plants were chilled more than six weeks in vitro. Among the four species tested, flowering was observed only in a $F_1$ hybrid 'Jiknyeo' with 62.5% flowering plants when it was chilled at $25^{\circ}C$ for three weeks under a lighted condition. Percent flowering plant was affected by duration, temperature, and light condition during chilling treatment. Three-week chilling at $4^{\circ}C$ under a darkened condition significantly reduced days to flowering. These results suggest that the low temperature requirement for flowering is not qualitative but quantitative in Campanula species. Further experiment with more number of plants is necessary to ascertain this conclusion.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.157-164
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• 2023

Codonopsis lanceolata (S. et Z.) Trautv. is mainly cultivated in Korea and China as a medicinal crop. C. lanceolata is difficult to produce plug seedlings in the summer, because C. lanceolata has a low germination rate and is vulnerable to high temperatures. Cold treatment is effective in breaking dormancy of seeds and increasing the germination rate. Shading cultivation can control the solar irradiance received by plants and reduce the damage by high temperatures and strong light. This study was conducted to examine the appropriate cold treatment period for the improving germination of C. lanceolata, and shading level during the summer seedling period. Cold treatment experiments were conducted for 0 (control), 1, 2, 3, and 4 weeks at 4℃ before sowing. In the shading experiment, C. lanceolata was grown for 45 days with 0 (non-treatment), 45, 75% shading levels. Cold treatment for one week significantly improved the germination energy. The plant height, leaf area, and fresh and dry weights of C. lanceolata seedlings were significantly increased under the 45% shading level. Total root length, root surface area, and the number of root tips were significantly higher in shading treatment (45 and 75%) than in non-treatment. The C. lanceolata seedling's compactness and Dickson's quality index were the highest at 45% shading level. Therefore, these results recommended sowing C. lanceolata after cold treatment for one week at 4℃, and 45% shading level could stably culture C. lanceolata plug seedlings during the high temperature period.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.277-286
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• 1987

Abscisic acid (ABA) content of the seed and endocarp during stratification were analyzed and then examined in relation to the embryo growth and germination. In mature red fruitlet, the ABA content was remarkably higher in sarcocarp than those in both seed ans endocarp. During the stratification before dehiscence, ABA content was gradually decreased in both seed and endocarp. After 90 days(dehiscent percentage; 96%) it came to 90 pmol/ g DW(69% decrease) and to 41 pmol/ g DW (80% decrease) in seed and in endocarp, respectively. The ratio of free from to total ABA content showed constant decrease in seed, but remained at higher level in endocap than in seed. Correlation between the decrease of ABA content and embryo growth showed higher significance in seed than in endocarp. During the stratification after dehiscence, ABA content in seed was gradually decreased at 4$^{\circ}C$ and 15$^{\circ}C$, After 90 days it came to 28 pmol/ g DW (69% decrease) and to 46 pmol/ g DW (49% decrease) at 4$^{\circ}C$ and at 15$^{\circ}C$, respectively. The ratio of free form to total ABA content was gradually increased at 4$^{\circ}C$, but remained almost constant at 15$^{\circ}C$. Correlation between the decrease of ABA content and days to first germination showed positive singificance only at 4$^{\circ}C$, whereas the correlation between the decrease and mean germination percentage per day showed negative significance at 4$^{\circ}C$, but positive significance at 15$^{\circ}C$. The above results indicate the ABA of the seed end endocarp during the stratification before dehiscence seems to be concerned with the immature embryo growth, but that of the seed during the stratification after dehiscence seems to show little effect on the germination capability(degree of breaking physiological dormancy).

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1452-1460
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• 2013

The purpose of this study was to investigate secondary drying effects on garlic quality, and to define the optimal secondary drying conditions for garlic preservation. The secondary drying tests used garlic that was naturally dried once and stored at low temperature. After secondary drying, the garlic was stored in a warehouse at room temperature. Tests were performed at different low-temperature storage periods (60, 105, 150, 195, and 240 days), secondary drying temperatures (35 and $40^{\circ}C$), drying times (1, 2, 3 days), and room temperature storage periods (15, 30, and 45 days). The results were compared with a non-secondary drying condition control. In general, the $40^{\circ}C$-2 days dry conditions showed the lowest weight-loss rate (5%) and rotting rate during room temperature storage. The sprouting rate increased by 20% during the initial 15 day-room temperature storage, along with a small increase after 30 days of room temperature storage. Increases in drying temperature and the period of secondary drying conditions caused a decrease in firmness. In addition, the sprouting rate was 10% higher, and rotting rate 5~10% higher, for the non-drying condition, compared to drying conditions. Based on our results, the $40^{\circ}C$-2 days drying condition is the optimal secondary drying condition for garlic storage.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.172-180
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• 2023

This study was carried out to determine the sprouting period of early and mid-season varieties, which includes 'Atlantic', 'Chubaek', and 'Superior', during the summer storage period in a semi-underground warehouse without cooling system. And also it was investigated the effect of chlorpropham [Propan-2-yl N-(3-chlorophenyl)carbamate, CIPC] treatment on the sprouting inhibition for the varieties. This study was conducted to figure out a sprout inhibitory effect when CIPC was applied to 1kg of the potato tubers at concentrations of 10 mg and 20 mg which are lower than the treatment concentrations of ca 30 mg prescribed by the positive list system (PLS). The internal temperature of the warehouse used in this experiment was lowered by 5℃ or more than the outside temperature. The difference between the lowest and highest temperature during the experiment throughout the day was 5℃. It showed the effect of reducing to 1/2 of the difference in outdoor temperature. As for the sprouting of potatoes, the extremely early variety 'Chubaek' sprouts appeared at the 6th week of storage of control and it was the fastest sprouting potato among the control groups of the varieties. Sprouting began to appear in the Superior at the 6th week of storage, while the 'Atlantic' sprouted at the 8th week of storage. The appearance of sprouts was suppressed in all treatment groups of 'Atlantic' and 'Superior' varieties in CIPC treatments. Sprouts were observed in all treatment groups of 'Chubaek' after the 7th week, but the elongations of the sprouts in tubers were completely inhibited until the 8th week of storage. 'Atlantic' and 'Superior' seemed to have a sprouting inhibitory effect even with a low CIPC concentration of 10 mg·kg^-1, with the exception of extremely early variety 'Chubaek' that breaks out of the dormancy quickly. Although weight loss occurred continuously during storage, it was minor loss of 0.7-1.6%. There was no consistent trend for changes of the loss in the varieties and CIPC treatments. Most common pathological disorder was the dry rot during the experiment, but only few were affected. The use of the tubers treated at 18℃ and 90% RH for 10 days and the rack of refrigeration system which lead to lack of convection seemed to have suppressed the spread of pathogens.