• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.93-98
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• 2001

Major characteristics have been studied on Daejappong which is autotetraploid brooded for mulberry fruit and Garmbacppong selected from the wild mulberry of Turkey. The number of chromosomes of Daejappong was 2n=56 recornized tetraploid, and that of Gambacppong was 2n=42 as a triploid. The percentage of seed formation, sank seed and germination of Daejappong were 48.2%,32.7%,90.0% respectively, on the other hand these of Carmbacppong were very low level as 41.0%, 1.9%,7.0% respectively. On the single fruit (sorosis) weight, Daejappong was large fruit as 4.39 g with light purple color, and Garmbacppong was medium fruit as 3.26 g with milk white color. Sugar contents (Brix %) and total acidities of Daejappong and Garmbacppong were 14.2%,0.45%, and 19.3%,0.15% respectively. Maturities of 2 cultivars were late and mulberry fruit yield of Daejappong was high and that of Garmbacppong was medium yielding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.458-465
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• 1993

Water culture experiments were carried out to elucidate the effects of N availability, temperature and water potential of culture solution on the uptake and assimilation of N and dry matter accumulation by barley seedlings. N assimilation and dry matter accumulation at 3 to 4 leaves stage in barley plants were maximized at about 3.4 % of N concentration in leaf. N assimilation by barley plants increased with increase of nitrate concentration up to 80ppm in the solution. Over this level nitrate began to accumulated in the leaves and stems proportionally to the N availability in culture solution. Nitrate reductase activity increased in parallel with the increase in the concentration of reduced N in leaves. N uptake by barley plants decreased markedly when water potential reduced below -2 bar or when temperature dropped below 5$^{\circ}C$. These results suggest that the basal application rate of N, 60kg per hectare, for the barley crop needs to be re-examined under the concept of N use efficiency with taking into consideration of temperature and soil N availability because about a half of N accumulated in the leaves of barley plant before wintering is known to be lost by winter killing of above-ground part of the plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.1
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• pp.47-53
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• 1980

Of 1, 428 entries examined to locate gene sources resistant to Septoria brown spot from the Korean native soybean collection, most lines were evaluated as highly susceptible, showing numerous leaf spots with surrounding yellowing tissue, while 136 lines of the entries showed the leaf spots without the yellowing. However, leaf defoliation was so much higher in inoculated soybean plants than those of uninoculated, regardless of leaf yellowing that resistance to Septoria brown spot could not be characterized by the lesion type. Various yield composing characters were negatively correlated to the leaf defoliation, suggesting that early defoliation incited by Septoria brown spot might result in significant yield reduction in soybean.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.2
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• pp.258-268
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• 1976

This study was conducted in order to know the ecology and to establish the control method of Potamogeton distinctus A. BENN. The tubers of Bog pond weed was almostly located at soil depth of 10 cm to 20cm, germination rates and number of formed tubers were different according to transplanting depth of soil. Effects of herbicides application on weeds were different according to leaf-stage of pondweed, and the pondweed were withered to death by absorption of Avirosan into the leaves. It was suitable to keep water depth at 3cm level until about a week after Avirosan application.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.93-100
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• 2015

This study was performed to examine the high temperature adaptability with CO₂ treatment for tomato under the condition of greenhouse cultivation during summer season. The indoor condition of CO₂ concentrations were controlled as control, 500 ppm, and 1,000 ppm for the greenhouse with the maximum air temperature of 44℃. With the observation of VPD (vapor pressure deficit) and CWSI (crop water stress index) by leaf-air temperature difference according to CO₂ treatment concentration, the plants with the CO₂ concentration of 1,000 ppm performed less water stress than those with the CO₂ concentrations of control and 500 ppm. The plants without CO₂ treatment performed the severest degree of water stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.52-57
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• 2006

This research was carried out to determine the effect of controlling nitrogen application on tiller development, yield, and quality of rice under scanty or excess seedling stands in direct-seeded rice on flooded soil surface. Seedling stand was set to 3 levels: scanty $(60/m^2)$, optimum $(120/m^2)$, and excess $(200/m^2)$. In the scanty plot, additional 4 kg/10a nitrogen was applied at the 3rd leaf stage to promote tiller development. On the other hand, applying 3.3 kg/10a nitrogen at 5th leaf stage in the excess plot was omitted to suppress tillering. Maximum numbers of tillers per plant were 15.2 and 8.6 in scanty and excess plots, respectively, as compared with 9.8 in optimum plot. Productive tiller rate decreased with the increase in number of seedling stands. Regardless of seedling density, the first tiller developed on the 3rd node of rice stem from the bottom. The primary tillers developed at 3, 4, 5, 6, 7 nodes in scanty plot, 3, 4, 5 nodes in optimum plot, and 3, 4 nodes in excess plot. The secondary tillers developed only in some portion of plants in scanty and optimum plots. The order of tiller emergence was negatively correlated to stem length, panicle length, non-productive tiller number, grain number per panicle, and fertility in scanty plot, and to perfect grain ratio in excess plot. In the optimum plot, however, the order of tiller emergence was not correlated to any of the mentioned characteristics. The perfect grain ratio of scanty plot was the highest because green-kerneled rice was a very small portion in the primary tillers as compared with those of optimum and excess plots. Yield indexes of scanty and excess plots were 99%, and 97%, respectively, of the yield (494 kg/10a) in optimum plot. In conclusion, when seedling stands are not at optimum level, rice yield and quality similar to optimum planting density level can be obtained by means of controlling nitrogen application.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.343-352
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• 2012

This experiment was carried out to report some data such as survival rate, tetraploid production efficiency, and agronomic characteristics of offspring from the induced tetraploid by the colchicine treatment in rye. The colchicine was soaked with 0.05%, 12 hours in dark condition and at two growth stages (green seed and 2nd leaf stage) in diploid ryes. Flow cytometry (FC) was proved to be efficient and rapid tool for screening ploidy levels in rye, showing around 40 to 60 in DNA amount (DAP1) corresponding to diploid and 80 to 110 tetraploid. There were 18.5% of survival rate at green seed treatment and 78% at 2nd leaf stage in average of two rye cultivars, Gogu and Jogreen, but in reverse 50.9% and 1.1% in the ratio of tetraploid to total tillers among the plants survived, respectively, resulting in 9.42% of tetraploid production rate in green seed treatment and 0.86% at 2nd leaf stage, respectively. In green seed treatment, there were 33% of survival rate in Gogu, 4% in Jogreen in 1st year, but 56% in Gogu, 21% in Jogreen and 49% in Charmgreen, respectively. The rate of tetraploid to total spikes among survived was 53.7% in Gogu, 32.4% in Jogreen, and 50.9% in average in 1st year, and 64.1% in Gogu, 51.5% in Jogreen, 60% in Charmgreen, and 60.5% in average in 2nd year. In green seed treatment, tetraploid production rate (survival rate ${\times}$ tetraploid ratio ${\times}$ 100) was 17.7% in Gogu and 1.3% in Jogreen and 9.42% in average in 1st year, and 35.9% in Gogu, 10.8% in Jogreen, 29.4% in Charmgreen, and 25.4% in average of three diploid rye cultivars. By the colchicine treatment with 0.05% for 12 hours in Gogu and Jogreen, 35 tetraploid plants were obtained and they produced 2,673 seeds with 148 spikes. There were 3.3-4.4 in the number of spikes per plant, 15.6-18.3 in grain number per spike, and 37.6 g in Gogu and 46.8 g in Jogreen in the 1,000-grain weight.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.189-194
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• 2001

It is possible to use hairy vetch as green manure for corn not only in corn single cropping but also in double cropping system of corn and fall oats. Fall oats and hairy vetch were mixed-sown after corn harvest and harvested as forage in the early of November, and then hairy vetch stubble was over-wintered and incorporated into soil at corn planting as green manure without N fertilizer (FO+HV-GM). Other treatments were fall oats without N fertilizer on corn (FO-0N) and with N fertilizer 200kg/ha on corn (FO-200N), hairy vetch green manure without N fertilizer on corn (HV-GM), and fell winter follow without N fertilizer on corn (WF-0N). Soil nitrate content, corn growth and nitrogen uptakes, and yield of corn were measured and compared during 2-year experimental seasons. Dry matter and N amount of hairy vetch at the plot of FO+HV-GM were 60% less than those at the plot of HV-GM. The N effect of hairy vetch green manure on corn at the plot of HV-GM was similar to that at FO-200N plot for two years. Soil nitrate at the plot of FO+HV-GM was below the half of those at plots of HV-GM and FO-200N at 6-leaf stage of corn. N uptake of corn at the plot of FO+HV-GM at silking stage was 30% less than those at plot of HV-GM and FO-200N. However, soil nitrate at 6-leaf stage of corn and the amount of nitrogen uptake of corn at silking stage increased two times and 30-40 kg/ha, respectively, compared with those at the plot of FO-0N. Corn yield at FO+HV-GM decreased about 2 ton/ha due to the decrease of corn grain weight in the first year compared with plot of HV-GM and FO-200N, but its difference was not shown in succeeding second year. Corn N uptake at FO+HV-GM decreased 60 kg/ha and 20 kg/ha in 1999 and 2000, compared with plot of HV-GM and FO-200N, respectively, but increased 30kg/ha and 45kg/ha compared with the plot of FO-0N in 1999, 2000, respectively. Therefore, it is estimated that hairy vetch green manure in fall oats-corn double cropping system can reduce nitrogen chemical fertilizer on corn as much as 50-100 kg/ha although its N effect is much lower than the N effect of hairy vetch green manure in corn single cropping of which N effect is over 200 kg/ha.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.57-69
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• 2012

This study was conducted to find the effective management of main weeds including herbicide-resistant Echinochloa oryzicola, Scirpus juncoides and Monochoria vaginalis in direct seeded rice on puddled paddy surface. The dominant dominances in direct seeded rice on puddled paddy surface were increased for three years between 2009-2011. In weed distribution in 2011, the occurrence density of S. juncoides decreased greatly, but it of E. oryzicola increased especially as compared with it of 2009. Benzobicyclon, mesotrione and pyrimisulfan were effective to sulfonylurea(SU)-resistant S. juncoides and M. vaginalis at 5 and 12 days after seeding, however, the efficacy of bromobutide to sulfonylurea-resistant M. vaginalis was decreased slightly at 12 days after seeding. And carfentrazon and pyrazolate were ineffective to S. juncoides. In direct seeded rice on puddled paddy surface which ACCase and ALS inhibitor-resistant E. oryzicola was not occurred, benzobicyclon+penoxsulam+pyrazosulfuron-ethyl ET, bromobutide+imazosulfuron+metamifop GR, and flucetosulfuron+mesotrione+pretilachlor GR showed the control effect over 94% to main weeds included sulfonylurea-resistant S. juncoides and M. vaginalis. The E. oryzicola dominating in direct seeded rice on puddled paddy surface were not any affected to the survival by treatment with recommended doses of cyhalofop-butyl and penoxsulam tested. The ACCase and ALS inhibitor-resistant E. oryzicola was effectively controlled by mefenacet and fentrazamide up to the 2nd leaf stage. In direct seeded rice on puddled paddy surface domiating coincidentally by herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis, "one-shot herbicide" included with mefenacet, fentrazamide, penoxsulam and metamifop could't be used because of low control effect or rice injury. The sequential treatment of benzobicyclon+thiobencarb SE and bensulfuron+mefenacet+thiobencarb GR controlled effectively the herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface. The days required by the 3rd leaf stage of herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface seeded in May 20 shortened by 4 days as compared with it of June 10.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.992-997
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• 2012

This study was conducted to get the basic information for absorb enhancement of accumulated soil nutrients in plastic film house. The grain sorghum (Sorghum bicolor L.) was sowing in plastic film house which soil nutrient accumulated moderately and was cutting at major growth period of sorghum. We were analyzed the regrowth pattern, biomass due to cutting time and amount of plant nutrient of grain sorghum. The obtained results were as follows. The heading date after cutting of sorghum in plastic film house was came to about 35 days. The accumulated of plant height were the longest as 379.4 cm in cutting at milk stage. The total biomass of sorghum in cutting at heading stage was 1.73 ton $10a^{-1}$ in cutting at heading stage. The high grain yields were produced with non-cutting and cutting at 10 leaves stage as 75~113 kg $10a^{-1}$ but the lowest grain yields were the cutting plots at booting stage as below 24 kg $10a^{-1}$. The content of nutrient in sorghum plant was low as progress of growth. The concentrations in aboveground sorghum due to plant parts was in order to leaves > panicle > stalk. The nitrogen content of sorghum was 0.6~0.7% in stalk, 1.5~1.6% in panicle and 1.8~2.3% in leaves. The amount of nutrient absorbed in sorghum was 4.2 kg $10a^{-1}$ in nitrogen, 1.7 kg $10a^{-1}$ phosphorus and 7.7 kg $10a^{-1}$ in potassium and the absorbing different by cutting time in order to booting > non-cutting > panicle formation ${\geq}$ milk ripe > 10 leaves stage.