• The Plant Pathology Journal
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• v.27 no.2
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• pp.110-115
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• 2011

Aggressiveness was studied in seven Plasmopara halstedii (sunflower downy mildew) pathotypes: 100, 300, 304, 314, 704, 710 and 714. Aggressiveness criteria including percentage infection, latent period, sporulation density and reduction of hypocotyl length (dwarfing) were analysed in one sunflower inbred line showing a high level of quantitative resistance. Genetic relationships were detected between the seven pathotypes using 12 EST-derived markers. Pathotypes 100, 300, 304 and 314 were characterized with shorter latent period and higher sporulation density than pathotypes 710, 704 and 714. All pathotypes showed high percentage infection values and caused a large reduction in seedling size except for pathotype 314 involved in dwarfing. Pathotypes 714, 704 and 314 had an intermediary genetic position between the pathotypes 100 and 710. No correlation was detected between aggressiveness traits and EST genotypes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.1
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• pp.31-37
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• 1988

Germination and seedling elongation of soybeans [Glycine max. (L.) Merr., cults. Bangsakong, Hill, Paldalkong, Danyupkong, Baegwun-kong. Kwangkyokong, Changyupkong and Hwangkeumkong] were measured at two temperatures (15 and 30$^{\circ}C$) and four polyethylene glycol 10,000 (PEG) solutions (0, 20, 30 and 35g/100g-H$_2$O). Adjustments of PEG solution were based on water potentials of 0.0, -0.5, -1.1 and -1.5 MPa at room temperature. Observations were made at 3, 6, 9 and 12 days for 15$^{\circ}C$ and 1, 2, 3 and 4 days for 30$^{\circ}C$. Fifteen seeds of each cultivar were placed on Whatman No. 1 (9cm) filter paper in plastic pertridishes, and adjusted to 15 ml of the proper PEG solution supplemented with 0.2 percent thiram using automatic syringe. The dishes were covered with cap. The seeds were germinated at a continuous temperature of 15 or 30$^{\circ}C$ under dark conditions for programmed period. Seedling moisture content and seedling length of eight soybean cultivars decreased as PEG concentration increased both at 15 and 30$^{\circ}C$. Cultivar differences in seedling moisture content and seedling length were found among eight soybean cultivars at temperatures of 15 and 30$^{\circ}C$. Larger sized cultivar absorbed more moisture than samller sized cultivar. However, reverse results were obtained on the seedling moisture content of each of eight soybean cultivars. Cultiver Hill and Paldalkong showed greater seedling length than the other six cultivars from 20 to 30g/100g water of PEG concentrations both at 15 and 30$^{\circ}C$. The results of this study indicated that germination test of soybean seeds in aqueous solutions of PEG has potential for screening soybean cultivars for improved emergence during moisture stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.204-212
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• 2019

The optimal application rate of a controlled release fertilizer (CRF) on the growth, yield, and seeding time of rice grown on seedling trays was investigated. The experimental field was located at $37^{\circ}22^{\prime}10^{{\prime}{\prime}}N$ latitude and $127^{\circ}03^{\prime}85^{{\prime}{\prime}}E$ longitude in Hwaseong, Gyeonggi-do, Republic of Korea. The soil in the paddy field was a clay loam. The CRF used in the experiment contained $300g\;kg^{-1}$ of nitrogen, $60g\;kg^{-1}$ of phosphate, and $60g\;kg^{-1}$ of potassium, respectively. The CRF was applied at the rate of 0, 200, 300, 400, 500, and 600 grams on rice seedling tray compared with the field application based on soil testing (control), respectively. The CRF can be applied as single application(which can replace basal fertilizer application and two top dressing application) directly to the seedling tray, and showed the minimum release at the seedling period. Considering the plant growth, nitrogen use efficency and yield of rice, the optimal application rate of developed CRF was 500 g per seedling tray and the yield of rice at this application rate was $4.92{\sim}5.04Mg\;ha^{-1}$. The regression formula between the rice yield and application rates of CRF was as follows ; "$Y=0.0002{\chi}^2+0.0963{\chi}+411.6$($R^2$ : 0.9922) in 2010 and $Y=8E-6{\chi}^2+0.2723{\chi}+344.04$($R^2$:0.9864) in 2011, Y : Rice yield ($Mg\;ha^{-1}$), ${\chi}$ : Application rate (grams) of controlled release fertilizer". The optimum application rates of CRF per rice seedling tray by regression formula was 498 grams in 2010 and 513 grams in 2011.

• Korean Journal of Agricultural Science
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• v.1 no.1
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• pp.9-26
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• 1974

1. Results in Nursery This experiment was carried out on the effect of the seed treament, soil preparations, kinds of covering soil and inside covering methods in two rice varieties, 'Tongil' and 'Akibare' to find out the most reasonable model of the flat nursery bed, with which lower cost is required comparing with the tunnel nursery. The results obtained are as follows: (1) The seedling of all plots of the ordinary seed were very poor compared to the plots of sprouted seed. (2) In case that the variety 'Tongil' was cultivated on the dry nursery bed, the good seedling percentage and the plant height rat io were significantly increased but the other characteristics of the seedling were not noticeable. (3) The kinds of the covering soil had not an effect on the seedling growth significantly. (4) Inside straw mulching was seemed effective for the protection in the case of the extreme high temperature and heavy rain fall, even though there was not significant differences between inside straw mulching and no treatments at the flat type nursery. (5) Difference of seedling growth between the flat type nursery and the tunnel type nursery was not significant. And it's reason was thought that the covering period of polyethylene film was short in semi hot nursery for the common early transplanting cultivation of rice. (6) The percentage of good seedling was higher at 'Akibare' than 'Tongil', variety but the number of seedling leaf and the seedling growth ratio in height were significantly increased in the variety 'Tongil'. The other seedling characters between there two varieties were not significantly different. 2. Results after transplanting This experiment was conducted to study on the ripening percentage, rice yield and disease, appearance of the seedling from sprouted seed plots including common irrigated nursery as check plot after transplantnig. The results obtained are summarized as follows: (1) The rice yield, the yield components and the appearance of leaf discoloration of both varieties, 'Tongil' and 'Akibare' were slightly betterat the plot of the standard tunnel nursery than that of the flat nursery with inside mulching or the among these three plots. (2) For 'Tongil' variety, the ripening percentage and the rice yield were significantly decreased at the common irrigated nursery compared with semi hot nursery. (3) The ripening percentage and the rice yield of 'Akibare' contrasted with 'Tongil' were significantly decreased at thesemi 'hot-nursery compared with common irrigated nursery. The main reason was thought to be the injury of the rice stripe disease (Rice stripe disease virus). Considering above mentioned experimental result, the seedling of 'Tongil' must be cultivated on the semi bot nursery for better ripening percentage as well as rice yield and for prevention of red discoloration. And as a model of semi hot nursery, the polyethylene covering nursery of standard tunnel type is most desirable but that of flat type with inside straw mulching is thought to be desirable too.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.4
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• pp.284-289
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• 1994

A nutrient solution culture experiment was conducted in the greenhouse of Suwon Campus, Kyung-Hee University from May 23 to July 11, 1994, to determine the effects of phosphorus application on seedling growth of Kwanganok and Hwengsungok cultivars of corn. Plants were harvested at weekly interval for seven weeks, at which time plant height, leaf area and dry matter yield of corn seedling were measured. The major results obtained are as follows. In without phosphorus pot, seedlings of Kwanganok and Hwengsungok cultivars have hardly been growing from planting to harvesting time. Plant height, leaf area and dry matter yield of both cultivars were increased more in the seedlings grown under complete treatment compared with the other phosphorus treatments. The total plant height, leaf area and dry matter yield during the whole period of Kwanganok and Hwengsungok cultivars were decreased in order of C>2P>3P>-P application pot. The crop growth rates of seedlings of both cultivars with in all treatments were slow until the 4th week after planting. Kwanganok with 2P and 3P treatment pot and C pot of Hwengsungok reached the maximum CGR at the 5th to 6th week after planting and showed declined CGR's thereafter, but Kwanganok C and Hwengsungok 2P treatment pots maintained a steady increase in CGR's until the end of the experiment period.

• Korean Journal of Medicinal Crop Science
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• v.7 no.1
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• pp.16-21
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• 1999

Seed-propagation of Solomon's seal (Polygonatum odoratum) takes 2 years to shorten the period for becoming a practical method. The experiment was done to establish a proper method of breaking the epicotyl dormancy in bulk seed-propagation. Seedlings with a bulbil were treated with $GA_3$ every 2 days for 4 or 8 days and chilling treatments at $3^{\circ}C$ were enforced for 4, 6, 8 or 12 weeks. Emergence- and growth-related characteristics were examined immediately after the treatments, 3 and 6 weeks later. Rate of cotyledonary sheath rupture immediately after $GA_3$ treatment was greater in its 8-day treatment than in 4-day although its effect disappeared later. However, any epicotyl treated with $GA_3$ solution did not elongate so that new seedlings disemerged over the bed soil. That resulted from not breaking the epicotyl dormancy since $GA_3$ did not rupture all of the cotyledonary sheath formed with several sheets and consequently, the solution did not reach it. The $GA_3$ treatment for bulk seed-propagation, therefore, was impractical method. On the contrary, the chilling treatment was able to be applied to the seed-propagation because of getting the cotyledonary sheath rupture and the epicotyl elongation. Seedling emergence and its growth after chilling treatment were influenced by chilling period although required at least over 6-week treatment for satisfactory results.

• Korean Journal of Environment and Ecology
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• v.20 no.4
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• pp.425-435
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• 2006

The objectives of this research were to investigate the drought resistance as well as the growth of Wisteria floribunda seedlings with the soil water conditions. The seedlings for the research were grown in pots with strict water content control on a frame located outdoors. During the experiments, the soil water contents were adjusted to 5, 10, 20, 30, 40, 50, 60, and 70%. In addition, the effects of Rhizobium inoculation on the growth of seedlings were investigated. The experimental results are summarized as follows: 1. The seedlings in the pots with 5% soil water content withered to death due to the water stress. Withering or any distinct growth was not observed from the seedlings in the 10% soil water content. It can be inferred from these results that about 5% of soil water content is the wilting point of W. floribunda seedlings and about 10% is the critical soil water content of its growth in this experiment soils. Therefore, it seems that W. floribunda possesses a good drought resistance. 2. From the analyses of the main growth parameters such as stem elongation, diameter growth, leaf area growth and total dry weight, it was found that the seedling growth can be improved with increasing soil water contents. The relation between each growth parameter(Y) and the soil water contents(W) was well described by a quadratic equation, $Y=a+bW+cW^2$. 3. In soil water contents higher than 20%, the seedling growth(Y) was remarkable along with-its extended growing period, and related to the growing period(D) by a quadratic equation, $Y=a+bD+cD^2$. 4. The artificial inoculation of Rhizobiun promoted the growth of Wisteria floribunda seedlings. 5. Rhizobium was found to be more readily inoculated and to form more root nodules compared to seedlings grown in higher soil water contents.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.230-236
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• 2022

This study was carried out to produce two-flowered seedlings, harvest them early in a greenhouse, and extend the harvest period. This study was carried out to effectively produce the second truss blooming seedlings to harvest tomatoes early and extend the harvest period. For production of the second truss blooming seedlings (one stem), the nutrient solution EC was supplied at 1.5, 2.0, 2.5 dS·m^-1, and dynamic management (3.0 → 3.5 → 4.5 dS·m^-1). The seedling period was 60 days, which was 20-40 days longer than conventional seedlings, and 10 days longer than the first truss blooming seedlings (cube seedlings). The plant height was 78 and 77 cm in EC 2.5 dS·m^-1 and dynamic management respectively, which was shorter than EC 1.5 dS·m^-1 with 88 cm. As for the EC in the cube before formulation, dynamic management had the highest EC 5.5 dS·m^-1, and the cube supplied with EC 1.5 dS·m^-1 had the lowest. The production yield by treatment did not a difference among in the second truss blooming seedlings, but the first truss blooming seedlings showed lower productivity than second truss blooming seedlings. The second truss blooming seedling were harvested 35 days after planting on June 4, the first harvest date, and the first truss blooming were harvested in 42 days on June 11th. There was no difference in plant height and root growth due to bending at frequency planting. In the study on the production of the second truss blooming seedlings (two stem), the nutrient solution EC was supplied under 2.0, 2.5, 3.0 dS·m^-1, and dynamic management (3.0 → 3.5 → 4.5 dS·m^-1). The seedling period was 90 days, which was 40-50 days longer than conventional seedlings and 10 days longer than the first truss blooming seedlings (cube seedlings). Plant height was 80 and 81 cm in EC 2.0 dS·m^-1 and 2.5 dS·m^-1 respectively, but was the shortest at 73 cm in dynamic management. EC in the medium increased as the seeding period increased in all treatments. The dynamic management was the highest with EC 5.1 dS·m^-1. There was no difference in yield among EC treatments in the second truss blooming seedlings, which had a longer seeding period of about 10 days, produced 15% more than the first truss blooming seedlings. In order to shorten the plant height of the second truss blooming seedlings, it is judged that the most efficient method is increasing the concentration of nutrient solution.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.370-376
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• 2009

To produce uniform seedlings of tomato and cucumber with inexpensive way, their seedling quality by different light sources was investigated. The raising of seedling was performed by red LED (light emitting diodes), blue LED, red-blue mixed LED or fluorescent light with a fixed PPF(photosynthetic proton flux) level, about $40{\sim}60{\mu}mol{\cdot}m^{-2}{\cdot}sec^{-1}$. In the both tomato and cucumber, the rapid extension of hypocotyledonary axis was observed in Blue LED than fluorescent light, but opposite result was found in Red and mixed LED. During the nursery period of tomato and cucumber, the fresh weight was the highest in Red LED as 74% increasement in tomato and 74% in cucumber. In the case of seedling quality after the tomato nursery, there was no difference in the positions of 1st flower cluster and the number of bearing-flower per flower cluster by each light source. In case of cucumber, until 20th node, the setting ratio of female flower was higher in LED than fluorescent treatment, and also more healthy fruit setting was found in LED. Therefore, we assume that the Red or mixed (Red 2 + Blue 1) LED is more favorable to produce high quality tomato and cucumber seedlings in closed nursery facility.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.328-333
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• 1983

Due to fast industrialization and reduced agricultural population, there has been increased farm mechanization to reduce the labor requirement. In rice production, mechanical transplanting has been increasingly popular due to the heavy labor requirement in hand transplanting and development of convenient transplanters. For mechanical transplanting, rice seedlings is grown in boxes with limited soils under super dense population, thus short period of exposure to unfavorable temperature and poor water management would cause severe damage to rice seedlings such as seedling damping off and the similar physiological disorders. Several chemicals were evaluated for their effectiveness to control the disease and disorders, and other effects as plant growth stimulants. 3-hydroxy-5-methylisoxazole-a soil fungicide, Metalozyl-a fungicide which controls mildew, SF 8002-the composite of above two chemicals, and Isoprothiolane-a fungicide which controls rice blast were found to be effective controling seedling damping off and similar physiological disorders, and improvement of physiological characteristics of the seedlings such as the amount of bleeding sap, rooting ability, negative geotrophism, and regrowth after cutting. The results indicated that the chemicals will be very effective raising healthy seedlings even under unfavorable environments by the improvement of physiological activities of seedlings and preventing seedling damping off and the similar physiological disorders.