• Research in Plant Disease
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• v.10 no.4
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• pp.241-247
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• 2004

Recently, we reported a satellite RNA (Paf-satRNA) which is encapsidated in a pepper isolate of Cucumber mosaic virus (CMV-Paf) regulated symptom attenuation of the helper virus. To characterize mild symptom domain of Paf-satRNA, a series of chimeric cDNAs of satRNAs were created by using full-length cDNA clones of Paf-satRNA and a Pep-satRNA, chlorosis-inducing satRNA in pepper plants, and analyzed for determinants of symptom attenuation. When compared the nucleotide sequences, the 3' and 5' terminal sequences of the two wild-type (wt) satRNAs contained relatively conserved sequences which are the typical to CMV satRNA. Ten bases insertions were found in PepY-satRNA, and two variable regions, 81st to 113th and 183rd to 265th from the 5'-end, were located in the middle parts of the satRNAs. To delineate the attenuated symptom-related domain for the Paf-satRNA, in vitro transcripts RNAs transcribed from the wt cDNAs and constructed chimeric cDNAs were combined with genomic RNAs, RNA1, RNA2 and RNA3, of CMV-Fny and inoculated onto Nicotiana benthamiana plants. These transcripts were fully infectious onto the N. benthamiana and infectivity was confirmed by the RT-PCR. Chimeric Paf(H/N)-satRNA and PepY(N/A)-satRNA as well as Paf-satRNA induced very mild mosaic or symptomless infection on N. benthamiana. By contrast, typical mosaic symptom and stunting of infected plants were induced when PepY-satRNA, PepY(H/N)-satRNA and Paf(N/A)-satRNA were infected to N. benthamiana. Paf-satRNA coinfected with CMV-Fny RNAs induced very mild to sympomless on pepper plants whereas PepY-satRNA-infected pepper expressed typical chlorosis mosaic symptom. Two kinds of chimeric mutants, Paf(H/N)-satRNA and PepY(N/A)-satRNA, induced mild mosaic or symptomless infection onto pepper plants, while PepY(H/N)-satRNA and Paf(N/A)-satRNA showed typical chlorosis and mosaic symptom with stunting. This results suggest that mild symptom-related domain for the Paf-satRNA was located on HpaI-NarI region.

• Current Research on Agriculture and Life Sciences
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• v.29
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• pp.43-53
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• 2011

The possibility of making Cheongukjang by the use of soy-powder and pill type re-made from soy-powder was investigated. Some of experimental results obtained are summarized as follows; 1. Regardless of three different types for the source material of Cheonggukjang, soybean seed, soy-power, and pill, the dry weight of fermented Cheonggukjang showed continuously decreasing trends along with the time of fermentation applied. 2. In all type of source materials, the length of viscous substance during fermentation was increased along with the time of fermentation, and the rate of elongation was much reduced after 48hr of fermentation. Out of four soybean varieties tested, Taekwangkong produced longest viscous substance fermented in the type of soybean seed. No viscous substance was formed when the depth of soy-powder in the fermentation box was shallow, one centimeter. 3. Not much difference was observed in the number of microbes, Bacillus licheniformis B1, in all soybean varieties. The number was proportionally increased in the type of powder but it increased rapidly from 12 hour to 24 hour with low rate of increase thereafter in the pill type. 4. Along with the time of fermentation in all types, the color of Cheonggukjang changed from yellow to dull. At the same time, the tone of color and chroma changed into reddish and yellow, respectively. 5. Along with the time of fermentation in all types, pH of Cheonggukjang changed in alkali. 6. Along with the time of fermentation, the content of isoflavone in Cheonggukjang increased by 48hr but decreased thereafter. 7. In general, the quality of Cheonggukjang fermented in types of soy-powder and pill re-made from soy-powder was lower than that of soybean seed. More study is seemed to be needed to produce high quality Cheonggukjang by the use of soy-power.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.209-216
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• 2010

This study was to find out optimum rice cultivars for organic farming in no-tillage paddy. A field research was conducted the yield, yield components, and qualities of thirty two Korean rice cultivars, and two Japanese rice cultivars. The column length of early rice plant was shorter in medium maturing rice cultivars compared to early, and medium-late maturing rice cultivars. Planthopper population per20-plant was lower in Ilpumbyeo, Dongjinbyeo, Hojinbyeo, Donganbyeo, and Sobeebyeo in that order while was higherin rice cultivars of early maturity. The disease severity of sheath blight was higher in Saechucheongbyeo>Chucheongbyeo>Namwonbyeo>Sangmibyeo in that order, on the other hand, that was lowerinHwaseongbyeo>Junambyeo>Saesangjubyeo=Hitomebore>Ilpumbyeo>Hwayeongbyeo in that order, respectively. The grain yield of Korean rice cultivars was significantly higher in 2.95 Mg $ha^{-1}$ for Hwasinbyeo, 2.91 Mg $ha^{-1}$ for Ilpumbyeo, 2.86 Mg $ha^{-1}$ for Sobeebyeo, 2.73 Mg $ha^{-1}$ for Naepungbyeo, and 2.70 Mg $ha^{-1}$ for Saegyehwabyeo compared with 1.38 Mg $ha^{-1}$ for Hwabongbyeo, 1.62 Mg $ha^{-1}$ for Hwayeongbyeo, and 1.78 Mg $ha^{-1}$ for Haepyeongbyeo of medium maturing rice cultivars, respectively. Toyo taste value of medium maturing rice cultivars tended to higher than that of early, and medium-late maturing rice cultivars. Ripening rate of rice cultivars was significantly positive correlated with Toyo taste value while negative correlated with protein content. According to principal component analysis, these results show that Sangmibyeo, Sangsanbyeo, and Odaebyeo for early maturity, Naepungbyeo, and Sobeebyeo for medium maturity, and Hwasinbyeo, Chucheongbyeo, and Sindongjinbyeo for medium-late maturity were optimum rice cultivars for organic farming in no-tillage paddy.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.657-663
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• 2012

The Ca deficiency is a serious problem in the propagation of domestically bred 'Seolhyang' strawberry through soil cultivation. The objective of this research was to investigate the impact of the Ca containing fertilizers on the decrease of Ca deficiency symptoms and in the growth of mother and daughter plants. To achieve this, chemicals of 1.125 mM $Ca(OH)_2$, 0.375 mM $MgCl_2$, and 1.25 mM KCl were blended to contain the K:Ca:Mg (4:2:1) and the influence was compared to a commercial fertilizer, Azuro-Calma ($NO_3$-N 13%, $K_2O$ 1%, CaO 16%, MgO 6%), when those were applied as solutions with the electrical conductivity (EC) controlled to 0.6 or 1.0dS ${\cdot}m^{-1}$. During 120 days after transplant, the Azuro-Calma was more effective than the combined fertilizer in the reduction of mother and daughter plants on which Ca deficiency was appeared. The application of two Ca containing fertilizers resulted in the heavier fresh and dry weights of mother plants. The treatments of 1.0dS ${\cdot}m^{-1}$ of two fertilizers were more effective than those of 0.6dS ${\cdot}m^{-1}$. The combined fertilizer was also more effective than Azuro-calma on the growth of above ground plant tissue. The results in length, fresh and dry weight of runners occurred from a mother plants showed that the treatment of 1.0dS ${\cdot}m^{-1}$ of combined fertilizer was most effective followed by those of 1.0dS ${\cdot}m^{-1}$ of Azuro-Calma, 0.6dS ${\cdot}m^{-1}$ of combined fertilizer, 0.6dS ${\cdot}m^{-1}$ of Azuro-Calma, and control. The fresh weights of daughter plants were heavier in the treatments of Ca application than those in the control treatment, but the differences between 0.6dS ${\cdot}m^{-1}$ and control were not significant. The above results indicate that Azuro-Calma is more effective in decreasing plants showing the Ca deficiency symptoms. However, the combined fertilizer of K:Ca:Mg is more desirable when we are concerned about the decrease of crops showing Ca deficiency as well as increase of the growth in above ground plant tissue.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.664-672
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• 2012

As an artificial light source, light-emitting diode (LED) with a short wavelength range can be used in closed-type plant production systems. Among various wavelength ranges in visible light, individual light spectra induce distinguishing influences on plant growth and development. In this study, we determined the effects of monochromatic LEDs on leaf shape index, growth and the accumulation of phytochemicals in a red leaf lettuce (Lactuca sativa L. 'Sunmang') and a green leaf lettuce (Lactuca sativa L. 'Grand rapid TBR'). Lettuce seedlings grown under normal growing conditions ($20^{\circ}C$, fluorescent lamp + high pressure sodium lamp, $130{\pm}5{\mu}mmol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 hours photoperiod) for 18 days were transferred into incubators at $20^{\circ}C$ equipped with various monochromatic LEDs (blue LED, 456 nm; green LED, 518 nm; red LED, 654 nm; white LED, 456 nm + 558 nm) under the same light intensity and photoperiod ($130{\pm}7{\mu}mmol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 hours photoperiod). Leaf length, leaf width, leaf area, fresh and dry weights of shoots and roots, shoot/root ratio, SPAD value, total phenolic concentration, antioxidant capacity, and the expression of a key gene involved in the biosynthesis of phenolic compounds, phenylalanine ammonia-lyase (PAL), were measured at 9 and 23 days after transplanting. The leaf shape indexes of both lettuce cultivars subjected to blue or white LEDs were similar with those of control during whole growth stage. However, red and green LEDs induced significantly higher leaf shape index than the other treatments. The green LED had a negative impact on the lettuce growth. Most of growth characteristics such as fresh and dry weights of shoots and leaf area were the highest in both cultivars subjected to red LED treatment. In case of red leaf lettuce plants, shoot fresh weight under red LED was 3.8 times higher than that under green LED at 23 days after transplanting. In contrast, the accumulation of chlorophyll, phenolics including antioxidants in lettuce plants showed an opposite trend compared with growth. SPAD value, total phenolic concentration, and antioxidant capacity of lettuce grown under blue LED were significantly higher than those under other LED treatments. In addition, PAL gene was remarkably activated by blue LED at 9 days after transplanting. Thus, this study suggested that the light quality using LEDs is a crucial factor for morphology, growth, and phytochemicals of two lettuce cultivars.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.913-920
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• 2010

This study was conducted to improve the seed germination by low temperature and $GA_3$ in $Orostachys$ $japonicus$ A. Berger (Jirisan) and $O.$ $iwarenge$ (Mak.) Hara (Jejuyeonhwa), Korean native plants. Observation of the seeds using a stereo microscope showed that all seeds of the two species have wrinkled surface and oblong shape. Seed size ranged 0.77-1.00/0.25-0.37 mm (length/width), indicating that the seeds are minute seeds. When the seeds of two $Orostachsis$ species were sown into petri-dish and placed in a plant growth chamber of 10, 15, 20, or $25^{\circ}C$, 'Jirisan' showed seed germination below 20% at all temperatures and 'Jejuyeonhwa' 80% at only $10^{\circ}C$. Seed germination of 'Jirisan' increased up to 44% at $10^{\circ}C$ by low temperature ($4^{\circ}C$) storage for 10 days, but decreased again at storage for more than 20 days. The seeds of 'Jejuyeonhwa' showed a large increase in seed germination by low temperature for 20-30 days, which was 95% at $10^{\circ}C$, but low temperature for more than 40 days significantly decreased seed germination. Dipping treatment in GA3 solution of $50-400mg{\cdot}L^{-1}$ for different periods (3, 6, 12, and 24 hrs) remarkably improved germination rate and speed in both species, 80-100% in 'Jirisan' and 90-100% in 'Jejuyeonhwa' at all concentrations and dipping times used in this study.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.4
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• pp.229-241
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• 2006

Global air temperature has risen by $0.6^{\circ}C$ over the last one hundred years due to increased atmospheric greenhouse gases. Moreover, this global warming trend is projected to continue in the future. This study was carried out to evaluate spatial variations in rice production areas by simulating rice-growth and development with projected high resolution climate data in Korea far 2011-2100, which was geospatially interpolated from the 25 km gridded data based on the IPCC SRES A2 emission scenario. Satellite remote sensing data were used to pinpoint the rice-growing areas, and corresponding climate data were aggregated to represent the official 'crop reporting county'. For the simulation experiment, we used a CERES-Rice model modified by introducing two equations to calculate the leaf appearance rate based on the effective temperature and existing leaf number and the final number of leaves based on day-length in the photoperiod sensitive phase of rice. We tested the performance of this model using data-sets obtained from transplanting dates and nitrogen fertilization rates experiments over three years (2002 to 2004). The simulation results showed a good performance of this model in heading date prediction [$R^2$=0.9586 for early (Odaebyeo), $R^2$=0.9681 for medium (Hwasungbyeo), and $R^2$=0.9477 for late (Dongjinbyeo) maturity cultivars]. A modified version of CERES-Rice was used to simulate the growth and development of three Japonica varieties, representing early, medium, and late maturity classes, to project crop status for climatological normal years between 2011 and 2100. In order to compare the temporal changes, three sets of data representing 3 climatological years (2011-2040, 2041-2070, and 2071-2100) were successively used to run the model. Simulated growth and yield data of the three Japonica cultivars under the observed climate for 1971-2000 was set as a reference. Compared with the current normal, heading date was accelerated by 7 days for 2011-2040 and 20 days for 2071-2100. Physiological maturity was accelerated by 15 days for 2011-2040 and 30 days for 2071-2100. Rice yield was in general reduced by 6-25%, 3-26%, and 3-25% per 10a in early, medium, and late maturity classes, respectively. However, mid to late maturing varieties showed an increased yield in northern Gyeonggi Province and in most of Kwangwon Province in 2071-2100.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.2
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• pp.131-136
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• 2005

This study was conducted from March 21 to July 7 in 2004 at JeJu Island to investigate the influences of seed-ing rates (4, 6, 5, 10 and 12 kg/10a) on creeping bentgrass vegetation. The result obtained were summarized as follows; plant height was getting longer as seeding rate increased from 4 to 12 kg/10a, Although it was no significance from 10 to 12 kg/10a. Root length, Minolta SPAD-502 chlorophyll reading value, leave and root weight increased as the plant height increased. The degree of land cover and density of creeping bentgrass also increased as seeding rate increased from 4 to 12 kg/10a, and the degree of land cover and density of weed decreased. The number of weed species on decreased as increasing of seeding rate. Then ranking of the dominant weeds were Digitaria adscendens, Chenopodium album var. centrorubrum md Poa annua (at 4 kg/10a seeding rate), Digitaria adscendens, Chenopodium album var. centrorubrum and Stellaria media (at 6 kg/10a seeding rate). Chenopdium album var. centrorubrum, Poa annua and Digitaria adscendens (at 8 kg/10a seeding rate), Digitaria adscendens, Chenopdium album var. centrorubrum and Steilaria media (at 10 kg/10a seeding rate), Chenopdium album var. centrorubrum, Digitaria adscendens and Stellaria media (at 12 kg/10a seeding rate). These results showed that the optimum seed-ing rate is 10 kg/10a for growth of creeping bentgrass in volcanic ash soils of Juju island.

• Korean Journal of Weed Science
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• v.12 no.1
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• pp.16-30
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• 1992

A field experiment was done to evaluate the growth response, rhizobia nodulation and vesicular-arbuscular mycorrhizal fungi (VAMF) infection of soybean treated with the different concentration of three-herbicides, alachlor, simazine, linuron. The results obtained were summarized as follows ; Emergence rate of soybean was non-significantly decreased by increasing the herbicide concentration. In simazine treatment, low emergence rate showed even in recommended concentration, especially the lowest emergence rate in treble concentration of recommended dose was about 50%. The plant length of soybean lowered by increasing the herbicide concentration, but there were almost no differences in recommended dose. Particularly that in a high concentration of herbicides at three weeks after treatment(WAT) was decreased remarkably. In the plant diameter of soybean shoot, no differences in the recommended concentration of alachlor and linuron at 2 WAT, but those of recommended dose was decreased with the lapse of time, and the lowest treatment was simazine-treated plot. Leaf area and fresh weight of soybean tended to decrease over the control even in recommended concentration and it was decreased with the increment of the herbicide dose. Yield component, fresh weight of rhizobia nodule and chlorophyll content of soybean leaves were reduced with the increment of herbicide dose, espicially remarkable tendency was revealed in simazine-treated plot. Seasonal infection rate of VAM showed a slight decrease by increasing of herbicide dose, and the lowest infection was simazine treatment. Significant correlation was realized among the reduction of rhizobia nodulation, VAM colonization and the agronomic characters of soybean and it was considered that the reduction of rhizobia nodulation and VAM colonization by misapplication of the herbicides might be a causal factor for decrease in soybean yield.

• Korean Journal of Weed Science
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• v.12 no.3
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• pp.200-222
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• 1992

The results of recent researches for improvement of seedling stand in direct seeded rice on the dry paddy in Korea were summarized as the following ; a variety to be cultivated should be chosen the characteristics of high percentage germination under low temperature, shorter period of shoot emergence, and better growth of the mesocotyl and shoots. Meanwhile, there was 40% increase in seedling stand at the treatment of removal of the seed awn under using the drill seeder. After seeding the rice seed covered with soil of 3cm depth was better seedling emergence and also there was the hightest seedling emergence at the 70% of moisture content of the soil. In addition, the application of the Release containing GA 10% enabled to increase the seedling stand and furthermore it was effective under deep seeding depth. The optimum seeding date should be seeded around May 10 when mean air temperature is above 12-13$^{\circ}C$ so that may establish more less 70% in seedling stand. Based on an appropriate seedling stand of 150/$m^2$, the optimum seeding rate was 5kg/10a. It was the best in seeding method using drill seeder and the most desirable recommended seeding method was the drill seeder in terms of seedling stand. In order to improve seedling stand water management was more effective in canal irrigation and in drainage at 6hr after irrigation following by the seeding process. On the other hand, for the increase of seedling stand under flooded condition a variety might have characters being better germination at low concentration of dissolved oxygen and vertically deeper growing of the crown root. Also, seedling stand was able to increase with the seed coating of $CaO_2$in the flooded soil. It was possible to be seeded on the early part of May being mean air temperature of avove 10$^{\circ}C$ and the optimum seeding rate was 5kg/10a. For an effective water management water would be flooded up to 3cm depth for 2-3 weeks after seeding. The rice plant grown under the direct seeded cultivation might be not so much strong in lodging resistance compared to that grown under the transplanting and moreover direct seeded rice cultivation under flooded condition would be more weak growth of the rice plant than that on dry paddy. Meanwhile, the lodging would be affected by the seeding rate, the soil depth after seeding. and seeding method even in the same variety. In particular, roots in the lodging pattern of direct seeded rice cultivation under flooded condition were largely distributed on the soil surface so that resulted easily in the lodging. In general, the lodging resistance would be greater as seeding rate and amount of N fertilizer application are lower and soil depth after seeding is higher. Among the introduction of different seeding method the high ridged drill seeding method on dry paddy soil resulted in the lowest in the lodging index and also it was lower in the drill seeding method than in the scattering seeding method under flooded condition. In case of more than 150 seedlings per $m^2$ there was a severe lodging due to high lodging index at the 3rd and 4th internodes. The effective lodging prevention was able to at the treatment of the Inabenfide at 45 days before heading and the Uniconazol at 15 days before heading which caused the shortage by 10-15cm in culm length. Also, fertilizer management using split application of nitrogen would be contributed the reduction of lodging at the rate of 20-30-20-20-10%(basal-5th leaf stage-7th leaf stage-panicle initiation stage-heading stage) on the dry paddy soil.