• Horticultural Science & Technology
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• v.28 no.4
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• pp.529-534
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• 2010

Occurrence of wilted symptom in watermelon plant ($Citrullus$ $lanatus$ L.) is known to be caused by physiological disorder. The symptom results in the loss of fruit production and thus the economical loss of watermelon growers. The incidence of symptom is often found from the middle of March to the end of May in the major watermelon crop production areas of Korea (i.e. Uiryeong, Gyeongnam (lat $37^{\circ}$56'64"N, long $126^{\circ}$99'97"E)). Despite of extensive information about the physiological disorder, little study has been conducted to understand a relationship between the wilted symptom and accompanying environment factors (e.g. temperature). This study aimed to investigate effects of environmental conditions amended by a forced-ventilation system on physiological characteristics of watermelon and incidence of the wilted symptom. Watermelon plants were grown from January to May, 2009 with either the forced-or natural-ventilation treatment in a greenhouse located in the Uiryeong. In the result, the forced-ventilation treatment decreased the air, leaf and root-zone temperature approximately $4.5^{\circ}C$, $5^{\circ}C$ and $3^{\circ}C$, respectively, compared to the natural-ventilation. The fruit growth rate was maximized twice during the entire growing period. The higher rate of fruit growth was observed under the natural-ventilation than the forced one. Maximization of the fruit growth rate (approximately 430 g per day) was first observed by 12 days after fruiting under the natural-ventilation treatment, while the second one (approximately 350 g per day) was observed by 24 days after fruiting. The wilted symptom started occurring by 22 days after fruiting under the natural-ventilation, whereas no incidence of the symptom was found under the forced-ventilation treatment. Interestingly, the forced-ventilation lowered the fruit growth rate (approximately 320 g per day) compared to the natural one. Maximization of the fruit growth rate under the forced-ventilation was found at 4 days later than that under the natural one. This result coincided with a slower plant growth under the forced-ventilation treatment. These results suggest that the forced-ventilation slows down extension growth of fruit and plant, which may be associated with lowering leaf temperature and saturation deficit. We suggest the hypothesis that the forced-ventilation may alleviate stress of the wilted symptom by avoiding extreme water evaporation from leaves due to high temperature and thus by reducing competition between leaves and fruits for water. More direct and detailed investigations are needed to confirm the effect of the forced ventilation.

• Journal of Bio-Environment Control
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• v.30 no.3
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• pp.188-195
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• 2021

This study was conducted to investigate the growth and quality characteristics of melon (Cucumis melo L.) cultivars and the irrigation requirements for cultivars. In our previous study in 2019, twelve melon cultivars including 'Dalgona' were examined for their cultivar characteristics under the same irrigation condition for all cultivars, and sorted into several groups based on different growth condition; for the internode length (from 0 to 20th node), leaf area, and fruit weight, 'Kingstar' belonged to the largest group, 'Worldstar' the middle group, and 'Dalgona' the smallest group. After analyzing the results of the previous experiment, 'Dalgona', 'Worldstar', 'Kingstar', and 'Rubyball' were selected as test cultivars for the growth group in 2020, and irrigated according to different irrigation levels for each cultivar. The control of the irrigation volume for each melon cultivar by monitoring the drainage rate during the cultivation periods showed that all four cultivars required a similar amount of irrigation in the 'early growth' stage where crops grew at about the same rate. From 'flowering time', however, the change in irrigation requirements showed a similar tendency for 'Worldstar' and 'Kingstar' and for 'Rubyball' and 'Dalgona' respectively. A sudden change in each irrigation volume was observed from the fruit set; 'Dalgona' began first to decline and 'Rubyball' was second, followed by 'Worldstar' and 'Kingstar'. In conclusion, the irrigation volume was the largest in 'Kingstar', followed by 'Worldstar', 'Rubyball', and 'Dalgona' in the same order as the growing amount of plant length, leaf area, and fruit weight. Therefore, it is necessary to control exactly the irrigation volume by reflecting the unique growth characteristics of each cultivar for the production of high-quality fruit in melon hydroponics, and especially to use great care when different cultivars are cultivated together.

• Journal of Bio-Environment Control
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• v.19 no.2
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• pp.82-87
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• 2010

To investigate effects of kind of pot for raising of seedling (single plastic pot, double plastic pot, circular peat pot, square peat pot) and planting method of the pot (3/3, 2/3, and 1/3 by the buried degree of pot height) on watermelon (Citrullus lanatus) growth, this research was conducted under plastic film house. Since planting of seedlings, number, area and photosynthesis rate of leaves, plant height and weight were superior in seedling grown in double plastic pot than those grown in the others. In fruit characteristics harvested at 12 weeks after planting, fruit height, diameter and weight were longer in double plastic pot than in the others, also fruit peel thickness and hilum diameter were thicker and shorter. Initial growth of the plant after planting with seedling grown in double plastic pot was superior in method buried the 2/3 degree of the pot height than the other methods.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.385-391
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• 2013

In this study, the availability of slurry composting and biofiltration (SCB) solution as an alternative for synthetic nutrient solution was determined by monitoring the growth, fruit yield, and fruit quality of cherry tomato (Solanum lycopersicum L. 'Unicon'). Treatments for nutrient solution were consist of SCB 1/2N, 1N, 2N, and commercial nutrient solution 1N (CNS 1N) based on nitrogen concentration (218.32 $mg{\cdot}L^{-1}$) of cherry tomato nutrient solution (control 1N). All nutrient solution including SCB solution (440~520 mL per day) was supplied to rock wool medium using a timer. After 31 days of transplanting, fresh and dry weights of shoots, leaf area, plant height, stem diameter, SPAD value and number of node were measured. After measuring growth characteristics of tomato plants, total fruit yield, ratio of marketable fruit yield, fruit weight, total soluble solids content, total acidity, total phenolic concentration, and antioxidant capacity were determined once a week for 7 weeks. As a result, among the SCB treatments, SCB 1/2N was similar to control 1N and CNS 1N in terms of fresh and dry weights of shoots, leaf area, stem diameter, number of node, and SPAD value. Increased N concentration of SCB inhibited the growth of tomato plants. Total fruit yield of SCB 1/2N was 47% of that of control 1N which showed the best result. Percentage of marketable fruit yield in SCB 1/2N was about 58%. Soluble solids contents, total acidity, total phenolic concentration and antioxidant capacity was the highest in SCB 2N and the other treatments were not shown any difference. Blossom-end rot rarely occurred in control 1N and CNS 1N while SCB treatments without Ca induced the physiological disorder of 7~19%. In conclusion, SCB 1/2N was good for the vegetative growth of cherry tomato plants but reduced yield and quality of fruit compared with control 1N and CNS 1N. Thus, it is possible to apply SCB solution to grow cherry tomato plants hydroponically but in the consideration of fruits yield and quality additional supply of several minerals would be required.

• Research in Plant Disease
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• v.15 no.1
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• pp.51-53
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• 2009

The fruit rot of watermelon (Citrullus lanatus) occurred sporadically in the farmers field at Chojeondong, Jinju city, Korea, in 2007. The typical symptom was water-soaked, brown on the fruit, and than infected fruits were mostly rotted. White mycelial mats were spread over lesions, and then sclerotia were formed on fruit and near soil line. The sclerotia were globoid in shape, $1{\sim}3\;mm$ in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on PDA was $30^{\circ}C$ and the hyphal width was $4{\sim}8{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii. This is the first report on the fruit rot of watermelon by S. rolfsii in Korea.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.27-36
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• 2020

The study was compared for growth and yield of cherry tomato (Lycopersicon esculentum var. cerasiforme) crops as affected by various homemade liquid fertilizer (LF), commonly applied in the environmentally friendly farmhouses. LF treatment included UT (untreatment, water), OC (oil cake), BF (bone+fish meal), FA (fish amino meal), SO (sesame oil meal), and SF (starfish). Seasonal pH and EC in SO- and SF-LF rapidly decreased at 30 days after the storage, which were the highest EC of 0.6 - 0.8 dS/m, followed by BF-LF with 0.4 dS/m EC. T-N concentration in LF was the highest on the SF (0.0062%), followed by SO (0.0059%) and BF materials (0.0030%), which were all the great for the K concentration in the LF. P and Ca concentrations were the highest on the FA-LF, with the highest Mg concentration observed on the vegetable SO-LF. Soil EC was the highest on the SF-LF plots of 0.74 dS/m, with no significant differences between the treatments observed on the macro-nutrient concentrations in the soil and leaf. Leaf dry weight, leaf temperature, stem diameter, and plant height were investigated at once per 15 days. UT-LF reduced the leaf dry weight at all the measurement time while the plant height was low at an initial measurement but increased and similar to the other homemade LF treatments at a later measurement. Fruit yield and average fruit weight were the lowest on the UT-LF plots at 75 days after fertigation. Fruit diameter was increased by the BF-LF and SF-LF, with the highest fruit soluble solid contents and fruit coloring observed on the FA-LF. BF-LF maintained high fruit firmness.

• Research in Plant Disease
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• v.23 no.4
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• pp.322-333
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• 2017

In June and July 2015 and 2017, typical signs and symptoms of brown rot were observed on the fruit of Japanese apricot, peach, apricot, Japanese plum, and sweet cherry with incidence levels of 2-5% in Jeonju and Imsil, Korea. Early symptoms were small, circular, light brown spots that eventually destroyed entire fruit. Small sporodochia later appeared on the surface. Conidia isolated from each host were one-celled, hyaline, lemon-shaped and borne in branched monilioid chains. The optimal temperature range for hyphal growth of all the isolates was $20-25^{\circ}C$. The growth of hyphae was faster on potato dextrose agar and oatmeal agar than others. Multiple alignments using the ITS sequences from different host showed that they matched each other (100%). The ITS sequences showed 100% identity to those of M. fructicola. Based on the morphological characteristics and phylogenetic analysis via internal transcribed spacer (ITS), all the isolate was identified as M. fructicola. Pathogenicity of representative isolates was proved by artificial inoculation, fulfilling Koch's postulates. This is the first confirmed report on brown rot caused by M. fructicola on stone fruit in Korea.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.32-37
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• 2013

Relationships among climate changes, early frost, and fruit growth were studied during the final month to harvest of late-maturing 'Fuyu' persimmon (Diospyros kaki) to assess the changes in fruit characteristics during this critical period. The heavy frost on Nov. 16 defoliated more than 70% of the leaves, but with little damage on the fruits. However, all the leaves were defoliated by the heavy frost on Nov. 20, and all the fruits were cold-damaged by $-3.3^{\circ}C$ on Nov. 21. Fruit weight increased by 8-25 g per week from Oct. 25 (142 days after full bloom) to Nov. 15, reaching to 250 g, but it decreased by 3-4 g per week after the frost. Hunter a value of fruit skin gradually increased until the last harvest on Nov. 29 with a temporary halt in early Nov. when temperature was high, whereas fruit firmness rapidly decreased after the frost on Nov. 21. Fruit soluble solids were $15.7-16.1^{\circ}Brix$ for the final month. When some branches were covered with non-woven fabrics to avoid direct contact with frost, the fruits on the branches were not visually damaged by the low temperature although 40-60% of their leaves were defoliated on Nov. 16. However, low temperature on Nov. 20 and 21 defoliated all the leaves, causing cold damage on the fruits. There was a highly significant correlation between the fruit diameter and its weight ($R^2$ = 0.73-0.91). So, the regression equations could be used to estimate weight from diameter of the fruits sampled from the branches with the non-woven fabrics. The calculated fruit weight reached to a maximum of 240 g on Nov. 15. Daily increases in fruit weight were 1.1-2.5 g from Oct. 25 to 31, 1.9-3.5 g from Oct. 31 to Nov. 7, and 1.4-1.6 g from Nov. 7 to 12. However, fruit weight decreased by 0.3-1 g per day after the cold damage on Nov. 21. The results indicate that the most appropriate harvest time could be dependent on relationship of fruit growth to climate.

• Journal of Korean Society of Forest Science
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• v.103 no.3
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• pp.353-358
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• 2014

In order to obtain the basic data that could be used to evaluate the harvest time of new hardy kiwifruit cultivars (Actinidia arguta 'Saehan', 'Daesung' and 'Chilbo'), the seasonal fruit quality and ripening characteristics of hardy kiwifruit were investigated. Fruit sizes of 'Saehan', 'Daesung' and 'Chilbo' were increased from full bloom to 66 days, 85 days and 78 days, respectively. The growth curve of developing fruit of three cultivars showed double sigmoid. As a result of correlation analysis, the seed number per fruit showed a significant positive correlation with fruit weight (r = 0.94~0.97, p<0.01). Fruit length, width, thickness, weight, soluble solid content and titratable acidity were significantly different among the cultivars. Titratable acidity was increased from full bloom to harvest time and the titratable acidity of 'Saehan', 'Daesung' and 'Chilbo' were 1.77%, 1.22% and 1.37% on havest time, respectively. Optimal harvest time of 'Saehan' was 108 days (23 Sep.) after full bloom, those of 'Daesung' and 'Chilbo' were 92 (9 Sep.) days after full bloom.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.366-366
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• 2017

There are about 2 genera and 49 species of Schisandraceae all over the world which grow 2 genera and 5 species in korea. As'Schisandra'genus, S. chinensis, S. repanda, S. nigra and S. viridicarpa are distributed. As 'Kadsura' genus, there is K. japonica species. Although S. chinensis is often used for food and herbal medicine, 'Cheongsoon'is the only cultivar in korea. Therefore cultivar breeding is required for standardized production of Schisandra chinensis. To select superior lines, characteristics of collected varieties was investigated. These collections were from all the country including Mungyeong, Muju and Jangsu. In the case of 'Schisandra chinensis', analysis of chemical compound is very important. Because in 'Korean Pharmacopoeia', Schisandrin has to contain more than 0.7% of sum of Shizandrin, Gomisin A, Gomisin N as standard compound. According to the investigation, the weight of SC-154 was the highest one that was 99g of fresh fruit and 60g of dried fruit in the 100 granulas of it. As the control group, the weight of cultivar 'Cheongsoon'was 57g of fresh fruit and 40g of dried fruit. The chemical compounds such as Shizandrin A, Gomisin A, Gomisin N and Shizandrin C from the collections were analyzed by HPLC. As a result, all average of total content was 1.67% satisfied with the standard that is over 0.7%. Among them, SC-13, SC-22, SC-40 and SC-45 had more than 2.0% of compound. In this case, the content of Gomisin N was relatively higher than that of the other collections. It can be used for high content compound breeding. This above results indicate that these findings could be used for breeding superior Schisandra chinensis through selection of high quality resource.