• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.360-367
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• 2020

BACKGROUND: The productivity and quality of blueberry (Vaccinium ashei Reade) greatly depend on the number of fruits in a plant. Especially, fruit set more than appropriate number negatively affects productivity and marketability due to the increased number of small fruits and delayed harvest time. This study was conducted to investigate proper timing and concentration for applying chemical blossom thinners such as ammonium thiosulfate (ATS) and UREA. METHODS AND RESULTS: ATS at 1.25% and 1.50%, and UREA at 6% and 8% were applied in four developmental stages, bud swell, pink bud, full bloom and petal fall. Fruit thinning rate was calculated based on the number of fruits harvested divided by that of flowers before applying blossom thinners. Ratios of leaf to flower and leaf to fruit were calculated based on the number of fully developed leaves in 25 days after full blossom divided by that of flowers or fruits, respectively. Chemical injury of leaves was investigated by calculating the number of leaves with chemical injury divided by the total number of leaves. Fruit thinning rates were 48% and 66% for UREA treatments at 6% and 8%, respectively, and 49% and 62% for ATS treatments at 1.25% and 1.50%, respectively, in the full bloom stage. In the petal fall stage, fruit thinning rates were 18% and 24% for UREA treatments at 6% and 8%, respectively, and 49% and 35% for ATS treatments at 1.25% and 1.50%, respectively. Leaf to fruit ratio (L/FR) increased by 109% and 188% compared to leaf to flower ratio in ATS treatments at 1.25% and 1.50%, respectively, and L/FR increased 93 and 196% in UREA treatments at 6% and 8%, respectively, in the full bloom stage. In the petal fall stage, leaf to fruit ratio increased by 60% to 100% in ATS treatments, but did not significantly differ from the control in UREA treatments. Fruit harvest was delayed in all treatments of all developmental stages except for 1.5% ATS and 6% UREA treatments at the petal fall stage, whose fruit harvest was two or three days faster than the control. CONCLUSION: The application of ATS and UREA for blossom thinning should be in the petal fall and full bloom stages for early and late harvest, respectively. Considering chemical injury, integrated harvesting and fruit size, however, it is appropriate to apply ATS at 1.5% in the petal fall stage to increase fruit productivity and quality in blueberry.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.1-7
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• 2008

Quality attributes of welsh onion (Allium fistulosum L.) as affected by harvest timing (November, December 2006 and January 2007) and storage temperature (5, 10 and $20^{\circ}C$) were investigated in terms of respiration rate, weight loss, decay rate, color, hardness, sensory quality. A higher respiration rate was found when welsh onions were harvested later and storage temperature was higher. A smaller weight loss was observed in welsh onions that were harvested in November and stored at temperature of $5^{\circ}C$, demonstrating a 9.35% reduction. In other words, there were a minimum difference of 2.15% and a maximum difference of 9.92% between the weight loss in test samples harvested in November and those of test samples harvested in other months. The decay rate was higher in welsh onions harvested in January. The degree of color was more stable in test samples kept at temperature of $5^{\circ}C$ than those kept at higher temperature (10 and $20^{\circ}C$). There were, however, no significant differences in color changes among test samples harvested at different times of the year. Thus color change is closely associated with temperature. Also, welsh onions were harvested in November and stored at temperature of $5^{\circ}C$ showed a good sensory quality.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.55-55
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• 1977

This experimental work was conducted in order to find out the optimum time of harvest of Japonica-type(Akibare) and Indica-type(Tong-il) rice variety for three harvesting systems by investigating the harvestirg losses and milling quality. The study was also concerned atout the nature and amount of grain losses incurred during the each sequence of post-harvest technologies, and based on these results, a modification of existing systems giving a minimum grain loss was attempted. Binder, combine, and traditional harvesting systems were tested in this study and five grain moisture levels were disposed according to the decrease of grain moisture. The results are summarized as follows: 1. The total losses of Akibare variety were ranged from 1.1 to 1.5 per cent for the traditional harvesting system, 2.1 to 4.8 percent for the harvesting system by use of binder, and 2.8 to 4.3 percent for the harvesting system by use of combine as the grain moisture content was reduced from 24 to 15 per cent. Milling recovery of the harvesting system by use of binder, 74.8~ 75.7 percent, was a little higher as it was compared to that of traditional harvesting system, 74. 3~75. 0 percent, and that of the harvesting system by use of combine, 73.8~ 75.0 per cent. Head rice recovery of mechanically dried paddy samples was higher than that of sun-dried paddy samples. 2. The total losses of Tong-il variety were ranged from 3.8 to 5.0 per cent for the traditional harvesting system, 5.2 to 10.0 percent for the system by use of binder, and 3.0 to 5.0 perent for the system by use of combine as the grain moisture was reduced from 28 to 16 percent.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.56-80
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• 1977

This experimental work was conducted in order to find out the optimum time of harvest of Japonica-type (Akibare) and Indica-type(Tong-il) rice variety for three harvesting systems by investigating the harvesting losses and milling quality. The study was also concerned about the nature and amount of grain losses incurred during the each sequence of post-harvest technologies, and based on these result, a modification of existing systems giving a minimum grain loss was attempted. Binder, combine, and traditional systems were tested in this study and five grain moisture levels were disposed according to the decrease of grain moisture . The results are summarized as follows ; 1. The total losses of Akibare variety were ranged from 1.1 to 1.5 per cent for the traditional harvesting system , 2.1 to 4.8 per cent for the harvesting system by use of binder, and 2.8 to 4.3 per cent for the harvesting system by use of combine as the grain moisture content was reduced from 24 to 15 percent. Milling recovery of the harvesting system by use of binder, 74.8 ∼75.7 percent, was a little higher as it was compared to that of traditional harvesting system, 74.3 ∼75.0per cent, and that of the harvesting system by use of combine, 73.8 ∼75.0 per cent. Head rice recovery of mechanically dried paddy samples was higher than that of sun-dried paddy samples. 2. The total losses of Tong-il variety were ranged from 3.8 to 5.0 per cent for the traditional harvesting system, 5.2 to 10.0 percent for the system by use of binder, and 3.0 to 5.0 per cent for the system by use of combine as the grain moisture was reduced from 28 to 16 per cent. 3. Milling recovery of Tong-il variety harvested by the traditional harvesting system was 72.3 ∼73.6 percent and it was lower when compared to that of 72.3∼75.0 per cent harvested by binder, and 73.0∼74.6 percent harvested by combine. 4. Head rice recovery of Tong-il variety harvested by the traditional harvesting system (58.

• YAKHAK HOEJI
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• v.47 no.2
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• pp.57-68
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• 2003

Under the active search for biologically active novel agents for cancer prevention and treatment, some agents have been found from plants which are easily available. Our previous research on them revealed that C. annuum L. var. angulosum Mill have high antiproliferating effect on cancer cells. However, it has not been known whether the anticancer efficacy is different according to each part of C. annuum L. var. angulosum Mill or whether it can be changed by timing of harvest or solvent for extraction. Thus we compared the efficacy of each part of C. annuum L. var. angulosum Mill and assessed how much difference in the efficacy can be made according to the time of harvest or solvents for extraction. We observed the morphologic change and apoptosis 48 hr after treatment with the extract of each part of C. annuum L. var. angulosum Mill in MCF-7 mammary gland adenocarcinoma cells and human hepatoma cells. We also counted cancer cells by trypan blue method and MTT method to check the cytotoxicity. The leaf extract showed the highest anticancer effect among all the parts of C. annuum L. var. angulosum Mill; 50％ and 70％ reduction in the number of cancer cells was observed at 25 $\mu\textrm{g}$/mι and 50 $\mu\textrm{g}$/mι, respectively. It was more than 2 times as potent as 5-fluorouracil (5-FU). We found chromosomal fragmentation, clumping, and destuction by PI staining, and DNA fragmentation by electrophoresis. In conclusion, this study suggests that leaf extraction using water as solvent has the highest antiproliferative and apoptotic activity in cancer cells compared with other parts of extraction.

• Research in Plant Disease
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• v.11 no.1
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• pp.39-42
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• 2005

Powdery mildew, caused by Sphaerotheca aphanis var. aphanis, is an economically significant disease of strawberry in Korea. When powdery mildew is not controlled adequately, it often spreads rapidly through strawberry plants and damage is associated with reduced yields. Proper timing of fungicide applications is, therefore, essential for effective disease control. This study evaluated the efficacy by application schedule of fungicides before harvest stage for preventing powdery mildew in 2001-2003. The systemic fungicides, azoxystrobin, kresoxim-methyl, and cupper fungicide DBEDC were applied preventively during the first part of the cultivating season. Preventative applications of DBEDC by dipping treatment before transplanting and kresoxim-methyl by foliar spray before blooming stage were one of the most effective control schedule tested to prevent and manage this disease. This research demonstrated the significance of application time to control of powdery mildew, particularly provided elimination unnecessary sprays of agrochemicals and reduction costs for strawberry growers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.277-282
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• 2016

The consumption of waxy corn is steadily increasing in Korea. Waxy corn is harvested before it reaches full maturity and consumed immediately or follwing cold storage. Glutinous and sweet kernels are preferred due to their high palatability. The kernel properties can change rapidly following harvest, and, therefore, optimal conditions to maintain the kernel quality of corn should be identified. In addition, the timing of harvest of waxy corn ear should be also determined for optimal marketable corn production. From 10 days after silking (DAS) to25 DAS. fresh ear weight and single kernel weight rapidly increased from 78.3 g and 1.13 g, respectively, to 224.9 and 3.61 g, respectively. However, by 30 DAS both fresh and single kernel weight decreased by 10.6% and 6.1%, respectively. Kernel hardness significantly increased up to 25 DAS, and a further slight increase in kernel hardness was observed at 30 DAS. Total sugar content in kernel decreased from 12.5% at 10 DAS to 3.5% at 35 DAS, which was the result of the conversion of sugars to starch during ear development. Crude protein content in kernel did not vary significantly in comparison to kernel hardness. During storage of ear, kernel hardness increased from $726g\;cm^{-2}$ at harvest to $1894g\;cm^{-2}$ following 28 days of storage at a low temperature ($0^{\circ}C$). Kernel hardness increased 2.5 fold from 15 DAS to 30 DAS. Soluble protein level in kernel increased until 10 DAS, following which a slight decrease was observed. The soluble protein content decreased from 1.85% at 5 DAS to 1.45% at 35 DAS. Total sugar content in kernel decreased regardless of storage temperature; however, the rate of reduction was lower at $0^{\circ}C$ than that observed following storage at $4^{\circ}C$ and $10^{\circ}C$. The rate of reduction in kernel moisture content was also lower at $0^{\circ}C$ than that observed at $4^{\circ}C$ and $10^{\circ}C$.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.213-219
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• 2009

An understanding of anthracnose (Colletotrichum acutatum) infections, including the infection of flowers and latent infection early in the season, is necessary to achieve successful control by means of properly timed spraying with a curative fungicide. In the present study, latent anthracnose infection of chili was investigated under greenhouse and field conditions in 2007-2008. Flowers on greenhouse-grown seedlings were infected and 11% of the young fruits subsequently showed symptoms of anthracnose. Apparently healthy-looking green peppers obtained from unsprayed fields or an organic market also exhibited symptoms of anthracnose after 4 days of incubation under high moisture conditions at $25^{\circ}C$; less than 1% of the peppers were found to be latently infected. To determine the natural timing of infection in the field, 3,200 fruits were wrapped in paper bags and then selectively unwrapped and examined for signs of infection. Field experiments were conducted at Suwon (cvs. Yokkang, Manitta, Olympic) and Asan (cv. Chunhasangsa) in 2008. The 7- to 10-day wrapping periods were July 25-31, July 31-August 7, August 7-15, August 15-24, and August 24-September 3. The 1-to 2-month wrapping periods were from July 4, July 31, and August 15 until harvest (Sept. 3). The controls consisted of 1,712 field-grown non-wrapped fruits. The rates of infection on the various cultivars were Yokkang 55%, Manitta 37%, Olympic 55%, and Chunhasangsa 20%. A distinct period in which anthracnose infection suddenly increased could not be identified; however, attempts to guess the approximate timing of field infection showed that 0-39% of the plants had latent infections, while depending on the cultivar, 8-14% of the plants examined in August and 4-13.5% of the those examined during May-July showed symptoms of infection. Delaying fungicide spraying by 24 and 48 h after artificial infection decreased the rates of infection by 10% and 25-30%, respectively. Chemical control of anthracnose based on a forecasting model should be considered starting from the transplanting stage, with spraying within a day after warning and care being taken not to latently infect apparently healthy pepper fruits.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.545-551
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• 2010

The primary objective of this study was to determine the relationship between fruit quality characteristics and pithiness fruit occurrence for confirming occurrence factors of pithiness tissues in 'Niitaka' pears ($Pyrus$ $pyrifolia$ Nakai). Fruits were harvested 4 times in 1 week intervals from 160 days after full bloom (DAFB) to 181 DAFB. Harvested fruits were separated with the specific gravity by Archimedes laws. Also, with specific gravity level in pear fruit, sugar content, acidity, and texture profile analysis (TPA) were investigated. Final verifiability of pithiness fruit was approved by eye observation at 90 days after storage. Also, in ASS (Alcohol Soluble Solid) and AIS (Alcohol Insoluble Solid), calcium contents were investigated. Although the differences in sugar and organic acid content were not significant in fruits divided by gravity, flesh hardness was depressed in fruits that showed low gravity. These results were more conspicuous in late harvested fruits (at 174 and 181days after full bloom) which showed low gravity, representing less content of AIS content and calcium in ASS and AIS when compared with early harvest fruits. Fruits of lower gravity below 1.0 measured with dipping induced the progression of pithiness symptom up to 76%. Consequently, harvest timing is a more concise factor in pithiness fruit occurrence although those symptom also affected by storage condition. Furthermore, the cause of pithiness fruit occurrence by late harvest is due to the lower cell wall binding calcium.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.151-155
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• 2011

The fungus Botrytis cinerea causes fruit rot of strawberry and the damages can result in harvest losses upto 50%. Proper timing of fungicide application is essential for successful control of Botrytis fruit rot, fenhexamid plus iminoctadine tris, cyprodinil plus fludioxonil, fludioxonil alone, and Bacillus subtilis QST713 were applied to individual buds, flowers, and green and red fruit of cultivar 'Seolhyang' ex vivo. Cyprodinil plus fludioxonil or fludioxonil alone was applied i) before and after a 5-hr period of low-temperature ($0^{\circ}C$) incubation ex vivo ii) in field trials. Strawberry flowers and red fruit were more susceptible to B. cinerea than the green fruits. Incidence of Botrytis rot with fenhexamid plus iminoctadine tris and cyprodinil plus fludioxonil was the lowest at flowering, whereas B. subtilis QST713 did not significantly among treatments. In 2010, incidence of Botrytis fruit rot was significantly reduced when fludioxonil was applied two times at 1 week intervals from 50% bloom in field trials. Cultivars Redpearl and Seolhyang were more susceptible to low-temperature than cvs. Maehyang and Akihime. Cyprodinil plus fludioxonil application was effective when applied before onset of the low-temperature treatment period. Fludioxonil showed the most effective when it was sprayed one and more than two times in before and post low-temperature condition, respectively. These results demonstrate that fungicide selection and timing can interact with stage of fruit development and low-temperature in determining effectiveness of suppression of Botrytis fruit rot.