• Horticultural Science & Technology
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• v.30 no.2
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• pp.123-128
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• 2012

A two year study was conducted on the effects of composted pig manure applications on organically managed intermediate-day onion ($Allium$ $cepa$ L.) with mid-season production. The manure application rates were 0, 4.0, 6.0, and 8.0 $ton{\cdot}ha^{-1}$, and accompanied by organic fertilizer with 240 $kg{\cdot}ha^{-1}$ nitrogen for all treatments. There was a positive linear effect on the marketable bulb yield with increasing applications of pig manure. However, pig manure rates of 6.0 or 8.0 $ton{\cdot}ha^{-1}$ did not affect the marketable yields or bulb weights at harvest. There was no significant difference between pig manure application rates and mineral concentration or nutrient uptake in onion bulbs. Soil pH and electric conductivity (EC) were lower at harvest compared to preplant soil, while exchangeable potassium and calcium contents increased at harvest. However, there were no significant effects on soil pH, EC, and organic matter or exchangeable cations caused by different pig manure application rates. Mineralized $NO_3$-N content was not affected by pig manure application rates except at transplanting and 129 day after transplanting. Based on the results of this study, when organic fertilizer is applied at a rate of 240 $kg{\cdot}ha^{-1}$ N, 6.0 $ton{\cdot}ha^{-1}$ composted pig manure should be adequate for producing onions using an organic production system.

• 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.

• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.160-165
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• 2009

This study was undertaken the effect of high temperature and high humidity on protein expression and especially plasma membrane (PM) $H^{+}ATPase$ of umbel with flowers of early cultivar 'Shinsunhwang' and intermediate cultivar 'Maebsihwang' of onion (Allium cepa L.). There were no visible any difference on the protein pattern from before flowering stage to full flowering stage of two onion cultivars, however, seed set stages were revealed induced/deduced protein patterns. At day 18, protein expression pattern of the high temperature and high humidity treatments of two cultivars was significantly reduced compared to controls. Furthermore, various protein expression of the high temperature treatment was more reduced compared to high humidity treatment. PM $H^{+}ATPase$ expression of the control plants of two onion cultivars was clearly shown, but was not detectable under high temperature treatment of the two onion cultivars using western blot analysis. PM $H^{+}ATPase$ expression of the high humidity treatment was faintly detected intermediate cultivar 'Maebsihwang', not early cultivar 'Shinsunhwang'. These results indicate that protein expression pattern and PM $H^{+}ATPase$ under high temperature treatment was considered to be more damaged compared to high humidity.