• Horticultural Science & Technology
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• v.34 no.6
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• pp.807-817
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• 2016

Many onion growers and researchers assert that differences in soil type, agricultural practices, weather, and duration of prolonged onion cultivation in a particular field could affect onion bulb quality. This study evaluates the bulb quality of onions grown in different regions and determines the correlations between bulb characteristics and postharvest loss during cold and ambient storage. Soil and onion bulbs were collected from fields in six onion growing regions in Korea, during the growing season of 2011-2012. The fresh weight, dry matter content, and carbon (C), sulfur and magnesium contents of the onion bulbs were significantly affected by the location in which they were grown. Bulbs grown in Muan had the greatest number of scales, thinnest scale thickness, and the highest total soluble solids (TSS) and total flavonoids (TF). Bulbs originating from Jecheon had the lowest pyruvic acid (PA), total phenolics and TF. Storage loss of bulbs from the different regions was similar in refrigerated storage, but differed in ambient temperature storage. Bulb fresh weight was positively correlated with scale thickness (r = 0.617) and cold storage loss (CSL; r = 0.398). Dry matter content was positively correlated with C (r = 0.958) and TF (r = 0.256) contents, while it was negatively correlated with CSL (r = -0.424). CSL was primarily affected by the fresh weight, as well as the dry matter, C, and PA contents of the bulbs, while ambient storage loss was primarily influenced by the amount of TSS.

• Korean Journal of Breeding Science
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• v.43 no.2
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• pp.126-132
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• 2011

The bulb storability of eight red and ten yellow onion (Allium cepa L.) cultivars grown primarily in Korea was evaluated. During storage, sprouting occurred earlier in red cultivars than in yellow cultivars. In addition, the ratio of sprouted to unsprouted bulbs increased more rapidly in red cultivars than in yellow cultivars. However, not all yellow cultivars had strong storabilities. Bulb storability of three yellow cultivars was as poor as that of red cultivars, suggesting only a slight possibility of a pleiotropic effect of color and bulb storability. Meanwhile, $F_3$ lines of a red cultivar selected based on stronger storabilities showed intermediate storabilities between those of the red and yellow cultivars, implying that strong storability could be obtained by successive selection. In contrast, $F_1$ hybrids from crosses between yellow and red breeding lines showed poor storability compared with the yellow cultivars, indicating that poor storability may be dominant over strong storability. The relationships between color and other traits that potentially affect storability, such as fresh and dry weight, water content, and firmness of bulbs, were evaluated. No significant differences in these traits were observed between the two colors, although the water content of yellow cultivars and the dry weight of red cultivars were slightly higher than their counterparts. Correlation analyses between bulb storability and other traits, including weight, water content, and firmness, also showed no significant correlations. In this study, no correlations were identified between bulb color, storability, and other traits. However, based on these results, red cultivars with stronger storabilities could be developed through successive selection of bulbs with stronger storabilities.

• Horticultural Science & Technology
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• v.29 no.4
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• pp.293-297
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• 2011

This experiment was conducted to elucidate the effects of mulching materials and removing time of the transparent polyethylene (PE) film on the growth of garlic at Uiseong experimental field, Korea. The experimental mulching materials comprised of transparent polyethylene film (0.025 mm) and net polyethylene (NPE). Plant height and leaf number of garlic were highest at PE treatment when the PE removing date was March 18 and this treatment also promoted the no. of cloves. Length of leaf sheath and bolting rate were highest and bulb weight loss rate was lowest at PE + NPE treatment when the PE removing date was March 18. But clove number was the lowest in this treatment compared to conventional PE film treatment. Conventional mulching method accelerated secondary growth rate but bulb weight loss was vice versa. There were statistically no differences in bulb diameter among treatments but conventional treatment positively focused on bulb diameter. Whenever PE film remove can suppress weeds compared to no mulching treatment but the dry weight of weeds were increasing trends as the removal dates of PE film were delayed. Transparent PE or PE + NPE treatments can be recommended to grow best quality garlic when PE film removing date is March 18.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.104-109
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• 2019

The crops recommended for the plant factory system are diverse. The importance of planting density in the plant factory is being recognized. The objective of this study was to determine the optimal planting density for growth and quality of kohlrabi in a closed-type plant factory system. The kohlrabi was grown under fluorescent lamps and nutrient film technique system. The growth and quality of kohlrabi were investigated under four different planting densities ($22plants/m^2(15{\times}30cm)$, $27plants/m^2(15{\times}25cm)$, and $33plants/m^2(15{\times}20cm)$). There were no significant interactions between Shoot fresh and dry weights per plant or bulb stem fresh and dry weights per plant and planting density. Shoot fresh and dry weight per area or bulb stem fresh and dry weight per area were the highest at $33plants/m^2$. There were no significant interactions between plant height, leaf area, photosynthetic rate, hardness, and chlorophyll content and planting density. Significant differences in Bulb stem height and diameter, and brix were observed. Bulb stem height and diameter and brix of kohlrabi were the highest at $22plants/m^2$. Based on our results, we conclude that the optimal planting density is $33plants/m^2$ for growth of kohlrabi, however, the optimal planting density is $22plants/m^2$ for quality of kohlrabi in a closed-type plant factory system.

• Korean Journal of Plant Resources
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• v.36 no.3
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• pp.237-255
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• 2023

Variations in phenotypic traits are important for onion genetic improvement. The aim of this study was to identify the phenotypic traits of temporary genetic resources and the best accessions for the development of onion breeding programs. Sixteen phenotypic traits of 79 onion accessions were studied. The descriptive statistics of phenotypic traits exhibited a high variation in onion accessions. Among the 79 evaluated accessions, 64.55% had a large bulb neck width and 44.30% had a circular bulb shape. Principal component analysis showed that six principal components (PCs) accounted for 72.65% of the total variation. The main factors contributing to PC1 were bulb weight, equatorial and bulb polar diameters, plant height, and degree of splitting into bulblets, whereas those contributing to PC2 were the bulb color of the epidermal cells of the fleshy scales and color of the dry skin on the bulb. The accessions were classified into three groups-clusters 1, 2, and 3. Cluster 2 accessions were the most suitable for selecting large and circular bulb-shaped onion cultivars. The phenotypic variation observed in this study may help to select potential accessions for breeding new onion cultivars.

• Journal of the Korean Wood Science and Technology
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• v.20 no.2
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• pp.51-60
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• 1992

This study was performed to investigate the effect of green sorting before drying on the high-temperature drying characteristics of southern yellow pine dimension lumber(2"${\times}$6"${\times}$12'). To test the advantages of weight sorting, green lumber was seperated into heavy(above 55 1b), medium(50-55 1b), and light(below 50 1b)weight classes. Pieces in each weight class were subgrouped into high(above 35%) and low(below 30%) latewood groups. Groups were dried and seperated by a standard commercial high-temperature schedule; dry bulb temperature $245^{\circ}$ F, wet bulb temperature $180^{\circ}$ F, and air velocity 1200fpm. The results obtained were as follows; 1. There was a highly significant correlation between annual rings per inch(X) and percent-latewood(Y). The regression equation was Y=24, 5047+1.3272X. 2. There were highly significant correlations between either annual rings per inch($X_1$) or percent-latewood($X_2$) a.d specific gravity in green wood(Y). Their regression equations were Y=0.4260+0.0081$X_1$ and Y=0.3749+0.0029$X_2$, respectively. 3. Heavier weight charges dried more slowly than lighter weight charges. 4. Board-to-board variation in green or dry moisture content was less for all seperate weight classes than for unseperated control charges. 5. Lower latewood pieces had higher initial moisture content than higher latewood pieces, and then drying time for lower late wood pieces was longer than higher latewood pieces.

• Journal of Plant Biotechnology
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• v.31 no.3
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• pp.249-253
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• 2004

The type of air lift bioreactor affected the root growth in ginseng adventitious root cultures. Among bioreactors used in this experiment, bulb type bubble bioreactor (BU) was the best to increase root growth (41.92 g dry weight). The kLa value representing the oxygen transfer capacity from medium to explants (6.98 h$^{-1}$ ) in BU with 5 cm bubble column was higher than other bioreactors. On the other hand, cylindric tube bioreactor (CT) without bubble column resulted in minimum root growth (38.55 g dry weight) and kLa value (5.25 h$^{-1}$ ). Furthermore, the root growth (50.30 g dry weight) in BU with 10 cm bubble column more increased than 5 cm bubble column. However, the kLa value do not affected the secondary metabolite such as ginsenosides. These results show that the bubble column in air lift bioreactor increase kLa value and increased kLa value stimulate the growth of ginseng adventitious roots.

• Food Science and Preservation
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• v.8 no.3
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• pp.258-263
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• 2001

This experiment was conducted to measure the physiological qualities and the chemical compositions of garlic bulb (Allium sativum L) stored in air and controlled atmosphere at 0$\^{C}$ for 4months. There were no significant differences in physiological qualities such as soluble solid, dry weight and firmness by O$_2$ and CO$_2$ concentrations during 4 months of storage. The surface color of garlic cloves changed toward more dark direction in Hunter color surface with storage. CA storage inhibited the sprout growth by 50% and had no significant difference in root growth. Garlic stored in CA showed lower level of pungency, especially CA of low oxygen concentration (1%) showed the lowest level of pyruvate. Garlic stored in high CO$_2$ concentration(20%) showed the lowest level of fructan concentrations and the highest free sugar concentrations.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.247-250
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• 2003

The investigation of ecological characteristics of Lycoris radiata was carried out in flooding (site I), half flooding (site II) and dry stands (site III). Seasonal change of air temperature showed similar patterns and that of light intensity showed quite difference among three L. radiata stands. Seasonal change of soil water content showed a great difference among three L. radiata stands. The study area was dominated by Pinus densiflora, P. thunbergii and L. radiata communities. The number of bulb in 1. radiata increased in September with bulb formation and decreased in January. Bulb weight in L. radiata was different from each site. The numbers of blossom were 23, 13 and 9, respectively in site I, II and III. The length of wreath were 17.0, 13.0 and 11.0cm, respectively, the length of stamen were 7.0, 6.4 and 6.5 cm, respectively and the length of stalk were 60.0, 45.0 and 42.0 cm, respectively in site I, II and III. The leaf of L. radiata developed rapidly in site I with sufficient water supply and lower light intensity, the number and the length of rootlets increased considerably in site III with insufficient water supply and higher light intensity, and the ecological characteristics in site II was intermediate between site I and site III. There was no great difference between the numbers of rootlets in site I and site II, which were due to sufficient water supply in two stands.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.321-329
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• 2018

A study was carried out to determine the influence of climatic environments on the growth characteristics and bulb quality of extremely early-maturing type onion grown at different altitudes, such as 60m, 200m, 350m and 700m above sea level (ASL). The mean air temperature during the growing season of extremely early-maturing type onion (October 18 to April 27) was $10.8^{\circ}C$, $9.6^{\circ}C$, $8.1^{\circ}C$ and $6.1^{\circ}C$ at 60m, 200m, 350m and 700m ASL. The mean air temperature during the bulb growth period (March 16 to April 14) was recorded $10.5^{\circ}C$, $9.4^{\circ}C$, $7.9^{\circ}C$ and $6.0^{\circ}C$ at 60m, 200m, 350m and 700 m ASL. Plant height, neck diameter, leaf number, leaf area, top fresh weight and top dry weight were significantly increased in growing of extremely early-maturing type onion at 60m ASL. Bulb/neck diameter ratio increased rapidly under the same temperature regime. The diameter and weight of the bulb were also the largest at 60m ASL during the bulb growth period (daily mean temperature of $12.5^{\circ}C$). At 60m ASL, there was the highest bulb size like a height, diameter and weight of bulb related directly on onion yield in the bulb growth period from March 16 to April 14. In contrast, yield and bulb quality were considerably decreased at 700m ASL during the bulb growth stage (daily mean temperature of $8.4^{\circ}C$). The quantity of extremely early-maturing type onion has gradually decreased as the daily average temperature drops below $12.5^{\circ}C$ during the bulb growth stage (March 16 to April 14). As a result, the lower temperature (daily mean temperature below $12.5^{\circ}C$) during the bulb growth stage significantly decreased the size and quantity of bulb in direction proportion.