• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.388-398
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• 2020

Watermelon yield mainly depends on soil water content controlled by irrigation in a plastic greenhouse. In this study, we investigated the effect of different soil moisture contents affected by irrigation starting point on growth, yield, and physiological responses of small-sized watermelons. Irrigation was initiated at 5 different levels of soil water content as a starting point with soil moisture detecting sensor after 14 days of transplanting, and stopped at 7 ~ 10 days before harvest. These treatments were compared with the conventional periodic irrigation as control. When soil had the lowest moisture content (-50 kPa), the overall shoot growth was retarded, but the root length and root dry weight increased. The photosynthetic parameters (photosynthetic rate, stomatal conductance, and transpiration rate) of watermelon leaves decreased significantly in the lowest soil moisture content (-50 kPa). On the other hand, the photosynthetic rates of watermelon leaves grown with irrigation starting point between -20 and -40 kPa were observed to be higher than those of other treatments. Fruit set rate and marketable fruit yield increased significantly at -30 kPa and -40 kPa. Proline, abscisic acid (ABA), total phenol and citrulline, which are known to contribute to stress tolerance under drought condition, increased as soil water content decreased, particularly, the largest increases were recorded at -50 kPa. From these results, it was found that an appropriate water supply adjusted with an irrigation starting point between -30 and -40 kPa could help to keep favorable soil water content during the cultivation of small-sized watermelons, promoting the marketable fruit production as well as inducing the vigorous plant growth and reproductive development.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.1
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• pp.54-62
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• 2015

To analysis of virus free sweetpotato effect, 5 virus free sweetpotato and virus normal sweetpotato varieties were planted in 5 different regions at 2010 year. The average yields of virus free sweetpotato are showed different results according to regions. Sinjami which cultivated at Iksan were increased maximum 68% compare to normal. However, Sinjami which cultivated in Hamyang were decreased yield 11% compare to normal. Analysis of tuber formation ratio of Sinjami, Yenhwangmi, Singeonmi which cultivated in Nonsan were decreased tuber number compare to normal. However, 3 varieties were all increased on Average storage root weight and yield of marketable storage root. In the results of analysis of marketable storage root according to cultivated regions and varieties, all varieties except Sinjami which cultivated in Hamyang were increased yield. Also, quality of virus free sweetpotato were enhanced 7 to 9 compare to virus infected sweet potato which showing average 3. Contents of starch between virus free and virus infected sweetpotato were not affected by virus. Virus free sweetpotato were more increased starch products according to increased total production yield. Also, $Brix^{\circ}$(%) was not showing difference between virus free and virus infected sweetpotatoes. In this experiment, Virus free sweetpotato are enhanced production yields and quality. Therefore, we suggested that virus free sweetpotato is one of the methods to reduce damage by sweetpotato virus.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.687-702
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• 2012

The objective of this study was to determine crop rotation effects on potato yield, soil chemical and microbiological properties from a short-term field experiment from 2010 to 2011 in Jeju Island, Korea. Potato cropping systems included continuous and rotation sequences of soybean (Glycine max(L.) Merr.), barley (Hordeum vulgare var. hexastichon), rapeseed (Brassica napus L.) and broccoli (Brassica oleracea var. italica). Crop rotations increased the yields of potato from 31% to 52% compared with continuous potato. Marketable yield of potato was highest under soybean plus rapeseed rotation by $20.97MT\;ha^{-1}$ and lowest under continuous cropping by $11.95MT\;ha^{-1}$. The incidence and severity of scab disease was significantly lower in tubers from crop rotation with soybean plus barley. Differences in marketable tuber yields among rotations were associated with potato scab disease. Especially, incidence and severity of potato scab were strongly correlated with soil pH, exchangeable calcium, and bacteria population of the soil. Crop rotations significantly increased soil pH, available phosphate, exchangeable K and Ca, especially in crop rotations with soybean plus barley or rapeseed. Soil microbial biomass C of crop rotations with soybean plus barley or rapeseed, was also significantly higher compared with monoculture. In conclusion, crop rotation may decrease the incidence of soil-born pathogen by increasing soil chemical properties and soil microbial biomass. Overall, potato crop productivity was generally maintained in rotations that contained soybean plus barley or rapeseed but declined under continuous cropping system.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.280-283
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• 2005

The growth and yield of ever-bearing strawberry $(Fragaria{\times}ananassa\; Duch.)$ 'Pechika' were compared after transplant treatment in the raised hydroponic culture on highlands in summer season. The transplant production methods compared were whole plant refrigerated, outdoor over-wintered, pot-refrigerated, and 1 -year-old transplants. Growth increment at planting was the highest in pot-refrigerated transplants. C/N ratio of the pot-refrigerated transplants was 39.2 which was higher than 19.5 of 1-year-old transplants. However, the growth increment up to the first harvest were not different among the treatments. The first harvesting date of 1-year-old transplants was August 14, which was 5-9 days late than in the other treatments. The average fruit weight was highest in the 1-year-old transplants with 12.6 g. Marketable yield was the highest in the pot-refrigerated transplants, followed 1-year-old, plant refrigerated, and outdoor over-wintered transplants. Therefore, the pot-refrigerated transplants are recommended for marketable yield increase in ever-bearing strawberry cultured on highlands.

• Korean Journal of Medicinal Crop Science
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• v.13 no.6
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• pp.268-272
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• 2005

This study was carried out to investigate the labor saving cultivation of C. auriculatum, which has much bigger root than local variety C. wilfordii, and tested three nonsupporting methods, i.e., untreated control, top pinching, and cutting of branch-top compared with I type stake. Top growth was more vigorous in staking cultivation than in nonsupporting cultivations. Among nonsupporting methods, main vine length and total length of main vines per plant were increased in order of untreated control > top pinching > cutting of branch-top, while the opposite is true to diameter of main vein. Number of leaves per plant was lower, but leaf length and leaf width were higher in cutting of branch-top than in other nonsupporting methods. Number of branched root and diameter of main root were bigger in cutting of branch-top and in staking cultivation, while length of main root and diameter of branched root were greater in staking cultivation and in top pinching than in other treatments. Although yield of marketable root per 10a was $17.9{\sim}22.6%$ lower, income was $8%{\sim}17%$ higher in nonsupporting methods than in staking cultivation by cost saving to staking installation. Among nonsupporting methods, yield of marketable root and income were 6% and 8% higher in cutting of branch-top than in untreated control, respectively.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.648-651
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• 2013

A new cultivar 'Daewang' strawberry was developed by the National Institute of Horticultural & Herbal Science for forcing culture in 2010. The cultivar 'Daewang' was originated from the cross between 'Maehyang', a high firmness cultivar and 'Wongyo 3111', a high sugar content in 2006. The cultivar shows erect plant type, vigorous growth habit, early flower bud differentiation with 12-15 flowers per cluster from planting on healthy nursery. Fruits of 'Daewang' are conical type having a bright red skin color, and 16-17 g in an average weight. 'Daewang' is suitable for forcing culture as time required for dormancy breaking ranged between 50 and 100 hours. This cultivar has excellent taste for high sugar/acid ratio as sugar content of $11.1^{\circ}Brix$, acidity of 0.39% with abundant texture and can be harvested by late spring because the fruit firmness of 'Daewang' was $18.2g{\cdot}mm^{-2}$ that was about $7.9g{\cdot}mm^{-2}$ higher than $10.3g{\cdot}mm^{-2}$ of 'Akihime' cultivar. But although total yield is not significantly different from 'Akihime' cultivar, its marketable yield is remarkably higher than that of 'Akihime' cultivar. Disease and pest resistance of 'Daewang' have a tendency to sensitive powdery mildew, anthracnose and spotted spider.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.283-290
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• 2017

In this study, the method to attach plastic film on the side vent from inside of greenhouse for the entire length was developed as the way to make crops less stressful while uniformly getting outside air into the greenhouse when ventilating using roof ventilation fans at single-span plastic greenhouse for oriental melon in a low-temperature period. The plastic film was installed from ground to 10cm below from the height where side vent is fully opened. In order to verify that the improved side vent can improve greenhouse environment and fruit yield, it was compared with the control plot of conventional side vent. Both greenhouses were not ventilated until February 25th, 2017. Air temperature in both greenhouses exceeded $40^{\circ}C$ in mid February. Therefore, it is judged that the greenhouse should be ventilated from mid February. Air temperature in the control plot exceeded $30^{\circ}C$ from late April. Therefore, it is judged that the plastic film attached to the inside of side vent should be removed in late April, or in early May at the latest. Soil temperature in the treatment plot in the mid Aril exceeded $20^{\circ}C$, which is suitable for growth, while that in the control plot was still below $20^{\circ}C$. Soil temperature in the control plot finally exceeded $20^{\circ}C$ in late April. The consumption of electricity was 47.2 kWh in the treatment plot, and 48.3 kWh in the control plot, which was no significant difference. The marketable yield of oriental melon in the treatment plot was 5,094kg, which was 23.9% more than that in the control plot, 4,113kg. The marketable fruit ratio was 73.5% in the treatment plot, and that in the control plot was 73.9%, which was no significant difference.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.176-179
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• 2001

To obtain the basic information of high yielding ability for varietal improvement and cultural practice, reciprocal grafts were made analyzed among five sweet potato cultivars. Five cultivars were characterized with the different in whose source and sink capacities. Grafting decreased main vine length, number of tuberous roots per plant, but its effects were different among grafting combinations. The growth of vines was affected more by scion, while growth and yield of under-ground were influenced more by stock. Grafting effects, interactions between stock and scion for main vine length and number of tuberous roots were highly significant in diallel grafting. The percentage of marketable tuberous roots was higher in the order of stem cutting＞self grafting＞reciprocal grafting.

• Horticultural Science & Technology
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• v.17 no.5
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• pp.569-571
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• 1999

The effects of training methods on growth and yield of white spine cucumber (Cucumis sativus L. cv. Sharp-1) were examined. The numbers of nodes, leaf area and root weight were in the order of, from high to low, ateral vine, main plus lateral vine, and main vine training. The total and marketable fruit yields were higher by the lateral training method than those by the other ones. The labor required for training was in the order of, from low to high, lateral vine, main vine, and main plus lateral vine training methods.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.352-357
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• 2006

Results of development and activity of roots by rootstock sort of oriental melon were followed; Grafted seedlings had higher root growth than self-roots seedlings and among grafted seedlings, Shintozoa and Elite rootstocks had higher root growth. Grafted seedlings had more xylem exudate, which connects activity of roots, than self-root seedlings. Development of roots and increase of xylem exudate were better in higher temperature. Marketable yield was higher in grafted seedling and quality of fruit was higher in self-root seedling.