• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.1
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• pp.15-20
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• 2013

This study was carried out to determine the optimum harvest stage of Italian ryegrass (Lolium multiflorum Lam., IRG) for maximum forage production during the spring season in Suwon, 2010. The variety of IRG was the early maturity type, 'Kowinearly', and six harvest stages (treatments) were first heading (T1), heading (T2), late heading to early bloom (T3), bloom to late bloom (T4), ripeness (T5), and late ripeness stage (T6). The dates of the first heading and heading of 'Kowinearly' were seen on 4 to 5 May, and 14 May, respectively. Plant length and dry matter (DM) percentage at first harvest were from 69 cm and 14.8% at T1 stage to 103 cm and 35.0% at T6 stage, respectively. The content of crude protein (CP) and in vitro DM digestibility (IVDMD) of T1, T2, T3, T4, T5 and T6 at first harvest were 15.6%, 10.6%, 10.1%, 8.1%, 7.3% and 5.4%, and 81.8%, 72.1%, 64.8%, 63.8%, 61.4% and 59.0%, respectively. The content of neural detergent fiber (NDF) and acid detergent fiber (ADF) were increased continuously with delayed harvest. A significantly higher yield of DM, CP and in vitro digestible DM (IVDDM) were observed for T3, and T4 (p<0.05). DM yield of 3,526 kg, 6,278 kg, 7,842 kg, 8,984 kg, 8,346 kg and 8,008 kg/ha, CP yield of 549 kg, 665 kg, 795 kg, 725 kg, 608 kg and 430 kg/ha, and IVDDM of 2,883 kg. 4,526 kg, 5,083 kg, 5,728 kg, 5,124 kg and 4,722 kg/ha at first harvest were recorded in T1, T2, T3, T4, T5 and T6, respectively. Regrowth yield of DM, CP and IVDDM were shown to be higher at T1 and T2 (p<0.05). However, no significant differences were observed between the two stages. Daily DM and DDM production of regrowth IRG were higher at T2, followed by T1. The total yield (at first and at regrowth) of DM, CP and IVDDM were significant higher for T2, followed by T3, T4 and T1 in order. At T2 stage, the yield was 11,089 kg, 1,254 kg, and 7,669 kg/ha in DM, CP, and IVDDM. In conclusion, the late heading to bloom stage was determined to be the optimum harvest stage for a single harvest, while the heading stage was a suitable stage of first harvest of 'Kowinearly' where two harvests were sought in a single year.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.274-283
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• 2020

Seed dormancy is an adaptive trait in which seeds do not germinate under unfavorable environmental conditions. Low dormancy seeds are easily germinated under optimal environmental conditions, and these characteristics greatly reduce the yield and quality of crops. In the present study, we compared the pre-harvest sprouting (PHS) rate of two cultivars, Joun and Jopyeong, using the Winkler scale after heading day and temperature of the test. The PHS rate increased as the Winkler scale after heading day increased from 700℃ to 1100℃ and the temperature of the test increased. In all conditions, the PHS rate of Jopyeong was higher than that of Joun. RNA-sequencing was used to analyze the cause of the high PHS rate. We analyzed the biological metabolic processes related to the abscisic acid (ABA) metabolite pathway using the KEGG mapper with selected differentially expressed genes in PHS seeds. We found that the expression of ABA biosynthesis genes (OsNCEDs) was down-regulated and that ABA catabolic genes (OsCYP707As) was up-regulated in PHS seeds. However, the quantitative real-time PCR results showed that Joun had a higher expression of OsNCEDs than that of Jopyeong, but OsCYP707As did not yield a significant result. Joun displayed higher ABA content than that of Jopyeong not only during ripeness time but also during PHS treatment. Taken together, we provided evidence that the ABA content remaining in the seed is important to the PHS rate, which is determined by the expression level of the ABA biosynthesis gene OsNCEDs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.470-476
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• 1986

In order to find out the optimum seeding date of Job's tears, this study was investigated ecological characters, yield components and yield of Jang Seong native variety at 6 seeding dates (March 20, March 30, April 10, April 20, April 30 and May 10). Emergence period and heading period were shortened as the seeding date was late, and the number of leaves on the main stem was increased as the seeding date was early. Maturing period was 63-66 days when we seeded in March 20, March 30, April 10 and April 20, and it was delayed 68-77 days when we seeded on April 3$^{\circ}$ and May 10. Culm length was longest in April 10 seeding (it was 186.6 cm), and it grew short in the early and the late seeding, but there was no significant difference among seeding dates. Stem diameter was thickest in April 10, and April 20 seeding, that is, thickened to 10.1 mm, and it was thin in the early and the late seeding. Productive tiller number per hill was increased most in April 10 and April 20 seeding, that is, increased to 6.2, and it was decreased in the early and the late seeding. 100 grain weight was heaviest in April 10 seeding; it was 10.7 g, and it was light in the early and the late seeding. Ripeness rate was highest in April 10 seeding (87.4%), and it was lowest in May 10 seeding (76.3%). Grain yield was highest in April 10 seeding (602.8kg per l0a); therefore this period is regarded as optimum seeding date. C. protein, C. fat, C. fiber and C. starch showed significant difference among seeding dates, and C. protein showed possitive correlation (r =0.9811 **) and C. fiber Negative collelation (r =-0.8937*) with seeding dates.

• Applied Biological Chemistry
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• v.40 no.4
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• pp.313-317
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• 1997

To assess the physiochemical characteristics of greenhouse Satsuma mandarin (Citrus unshiu Marc. var, miyakawa) produced in Cheju, were analyzed chemical compositions for fruits, external and internal factors influencing the edible quality. Changes in organoleptic value according to brix and acid content were also evaluated. The ratios of sucrose : glucose : fructose in citrus juice were 2 : 2 : 1.5. Citric acid as the main acid in the juice represented about 70% of total organic acid. Most of the amino acids were found to be nonessential amino acids. Deep yellow color of the citrus peel showed a significant relationship(r=0.563) with brix/acid ratio of the citrus juice, indicating the ripeness of the fruit. Since the acid content showed highly negative statistical relationship(r= -0.882) with the pH value of the juice, the pH value appears to be a simple indicator for the sourness of the fruit in the field test. The fruits were divided into 9 groups based on the brix/acid contents for sensory evaluation. The palatability patterns of each group changed depending on the acid content. The optimal ranges of brix/acid content for acceptable taste were 11 and $0.5{\sim}1.0$, respectively.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1178-1183
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• 1999

Essential oils were isolated from the peel of mandarin (Citrus unshiu Marc. Var. Okitsu) cultivated in Cheju Island. Among three different isolation methods investigated, simultaneous distillation gave higher yield 1.14%(w/w) than solvent extraction or cold pressing. The densities of essential oils were between 0.8409 and 0.8530, which showed no significant effect of the isolation methods. Some variations in the number of constituents detected and the content of d-limonene in the peel oils were observed depending upon the isolation methods. The citrus fruit was collected seasonally from the field and used as a sample for analysis. The peel thickness and the peel content of citrus fruit were around 2 mm and about 17% on wet weight basis, respectively, in harvest season. The maximum yield of essential oils was obtained in September from citrus peels just prior to ripeness and thereafter the yield had a tendency of decrease but remained over 1%(w/w). The relative content of d-limonene, the major constituent of citrus peel oils. increased gradually with ripening up to 68.69%(relative peak area, RPA). The other minor constituents were ${\gamma}-terpinene,\;{\beta}-elemene$, farnesene, hexadecanoic acid, ${\alpha}-pinene,\; {\beta}-myrcene$ and linalool in the decreasing order of their own contents of 7.75, 2.96, 2.29, 1.76, 1.63, 1.56 and 1.46%(RPA).

• Horticultural Science & Technology
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• v.31 no.2
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• pp.203-210
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• 2013

This study was conducted to investigate the optimum storage temperature and the effect of 1-methylcyclopropene (1-MCP) on the postharvest physiology and quality of plumcot (Prunus salicina Lindle. ${\times}$ Prunus armeniaca L.) 'Harmony' fruits. plumcot fruits were stored at 0, 5, 10, and $20^{\circ}C$, respectively, with three different ripeness stages grouped by skin color development. Furthermore, we treated $1{\mu}L{\cdot}L^{-1}$ 1-MCP was treated at $10^{\circ}C$ for 17 hours and stored at $10^{\circ}C$ for 12 days to evaluate the effectiveness for better shelf-life. The results indicated that lower storage temperature than room temperature effectively reduced the respiration rate with delaying quality changes. While, the fruits showed worse fruit taste than the fruits stored at 10 and $20^{\circ}C$. Reversely, the fruits stored at $20^{\circ}C$ showed more respiration rate and ethylene production. 1-MCP treatment effectively reduced the skin red color development, ethylene production, $CO_2$ and softening of plumcot 'Harmony' fruits. Overall data indicated that the optimum harvest time and storage temperature could be 30-50% red color and near $10^{\circ}C$. Postharvest 1-MCP application at the level of $1.0{\mu}L{\cdot}L^{-1}$ could maintain fruit quality well in plumcot fruits.

• The Korean Journal of Community Living Science
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• v.20 no.3
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• pp.397-411
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• 2009

The use of local product foods and fresh-cut products, the dietitian's recognition, the required items and the quality for school foodservice was investigated to increase the consumption of high-quality agricultural products. Data from 578 elementary schools, 228 middle schools and 116 high schools were collected by school foodservice personnels in each regional Education Administration in Gyeong-gi province. The first criteria of buying food materials was reliability/safety for all school foodservice. The second criteria were the origin of the product and freshness/ripeness for elementary and middle schools and high school, respectively. The most important consideration for selecting a supplier was the quality of the material. The appearance/status of the food was the first factor for buying food materials. The origin and the seasonality were very important for buying farm products. Dietitians in Gyeong-gi province recognized the local products, and used them weekly. The advantages of using local products were the quick supply, freshness and safety. On the other hand, the disadvantages were the lack of information and the uncertainty of supply. Sixty eight percent of the subjects had experienced the high-quality agricultural products in school meals, but the frequency was low. The main reasons for not servicing high-quality agricultural products were the high cost and the lack of trust on the quality. Among fresh-cut products, seasonings and root vegetables were purchased most frequently, but leaf vegetables was 5.7% only. The purchase of fresh-cut products was not frequent, but usually satisfied. The advantages of fresh-cut products were the reduced workload and waste, but the reason for not using them were poor hygiene and the high price. The diverse supply system and the promotion of the local product foods would be necessary since the most food materials were purchased through suppliers. In addition, the problems related to the high cost and distrust should be resolved to expand the consumption of the high-quality agricultural products and the fresh-cut vegetables. The institutions for certifying the quality should be needed to increase the confidence of these products.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.106-112
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• 2012

In order to understand the growth and ecophy -siological response of ginseng to global warming condition, we cultivated one and two year ginseng seedlings in control (ambient $CO_2$ + ambient temperature) and global warming treatment (elevated $CO_2$ + elevated temperature) from March 2010 to July 2011. Shoot appearance and initiation of flowering were advanced by 3-4 days in global warming treatment than in control. However, timing of fruit setting and seed ripeness was similar in both control and global warming treatment. Shoot length was longer in global warming treatment than in control, and also the number of leaves was much in global warming treatment. Fresh root weight was not different between control and global warming treatment. Photosynthetic rate was higher in global warming treatment than at control. Photosynthetic rate and transpiration rate were higher in two year seedlings than in one year seedlings at control, but was not different between seedling age of ginseng in global warming treatment. Water use efficiency was higher in one year seedlings than two year seedlings at control and global warming treatment. These results demonstrated that Korean ginseng more or less positively responds to global warming situation.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.697-702
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• 1995

Changes of physicochemical properties during the preparation of persimmon pickles and its optimal preparing conditions including salt concentration, soaking temperature, soaking time, amount of fermented soy paste, and ripeness of fresh pesimmon were investigated. The salinity and pH of soaking solution were rapidly dropped during 40 days of soaking, while their changes were negligible after 40 days of soaking. When the fermented soy paste was added to the soaking solution with $10{\sim}40%$ the pH dropped more slowly. Salt content in persimmon pickles was gradually increased during soaking and soluble tannin content was rapidly decreased during the first 10 days of soaking. L value of persimmon pickles was gradually decreased, but a/b value was slightly increased. The hardness of persimmon pickles was slightly increased up to the 20th day of soaking and then decreased. Most acceptable persimmon pickles were prepared when the less ripened fresh persimmons were soaked in 10% salt solution at $15^{\circ}C$ for 40 days, and the suitable amount of soy paste added to the soaking solution for preparing persimmon pickles was 20%.

• Food Science and Preservation
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• v.16 no.1
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• pp.1-7
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• 2009

Watermelons (Citrulus vulgaris Schrad) are usually sorted manually by weight, appearance, and acoustic impulse, so grading of maturity and internal quality is subject to inaccuracies. It was necessary to develop a nondestructive evaluation technique of internal watermelon quality to reduce human error. Thus, acoustic characteristics related to internal quality factors were analyzed. Among these factors, three (ripeness, presence of an internal cavity, and blood-colored flesh) were selected for evaluation. The number of peaks and the sum of peak amplitudes for watermelons with blood-colored flesh were lower than for normal fruits. The portable evaluation system has an impact mechanism, a microphone sensor, a signal processing board, an LCD panel, and a battery. A performance test was conducted in the field. The internal quality evaluation model showed 87% prediction accuracy. Validation was conducted on 72 samples. The accuracy of quality evaluation was 83%. The quality of samples was evaluated by an inspector using conventional methods (hitting the watermelon and listening to the sounds), and then compared with prototype results. The quality evaluation accuracy of the prototype was better than that of the inspector. This nondestructive quality evaluation system could be useful in the field, warehouse, and supermarket