• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.32-41
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• 2011

The objective of this study was to determine the fatty acid composition of newly developed tissues of germinated soybean seeds. Five soybean accessions with varied fatty acid composition were allowed to germinate in sand under greenhouse conditions. Seedlings were picked up after 4, 6, 8, 10 and 12 days of germination and freeze dried. The fatty acid composition of the newly developed tissues was analyzed by gas chromatography. Significant variation in fatty acid composition was observed between accessions, days of germination, and variety ${\times}$ day of germination in whole and the cotyledons. In the case of newly developed five tissues, significant variation in fatty acid composition were observed between days of germination except oleic acid for root, hypocotyl and epicotyl stem and except stearic acid for hypocotyl and unifoliate leaves while all the parameters were significantly different for accession. Significant interactions of accession and days of germination were observed for palmitic, linoleic and linolenic acid in all tissues; only for oleic acid in hypocotyl, epicotyl and unifoliate leaves; and only for stearic acid in root, hypocotyl, epicotyl and unifoliate leaves. During germination, the fatty acid composition of newly developed tissues changed dramatically but whole seedlings and cotyledons changed slightly. These tissues contained five major fatty acids as found in original seeds, but compositions were totally different from that of the seed: higher in palmitic, stearic and linolenic acid and lower in oleic and linoleic acid. New tissues conserved their fatty acid compositions regardless of genotypic variation in the original seeds.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.495-502
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• 2016

Italian Ryegrass (IRG), which is known as high yielding and the highest quality winter annual forage crop, is grown in mid-south area in Korea. The objective of this study was to evaluate the use of unmanned aerial vehicle (UAV) for the monitoring IRG growth. Unmanned aerial vehicle imagery obtained from middle March to late May in Nonsan, Chungcheongnam-do. Unmanned aerial vehicle imagery corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). We analyzed the relationships between $NDVI_{UAV}$ of IRG and biophysical measurements such as plant height, fresh weight, and dry weight over an entire IRG growth period. The similar trend between $NDVI_{UAV}$ and growth parameters was shown. Correlation analysis between $NDVI_{UAV}$ and IRG growth parameters revealed that $NDVI_{UAV}$ was highly correlated with fresh weight (r=0.988), plant height (r=0.925), and dry weight (r=0.853). According to the relationship among growth parameters and $NDVI_{UAV}$, the temporal variation of $NDVI_{UAV}$ was significant to interpret IRG growth. Four different regression models, such as (1) Linear regression function, (2) Linear regression through the origin, (3) Power function, and (4) Logistic function were developed to evaluate the relationship between temporal $NDVI_{UAV}$ and measured IRG growth parameters. The power function provided higher accurate results to predict growth parameters than linear or logistic functions using coefficient of determination. The spatial distribution map of IRG growth was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when $NDVI_{UAV}$ was applied to power function. From these results, $NDVI_{UAV}$ can be used as a new tool for monitoring IRG growth.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.290-290
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• 2017

Rice (Oryza sativa L.) is one of the most consumed staple food crop which is energy source as carbohydrate and also is considered as the important antioxidant sources including various phenolic compounds. According to the increasing demand of healthy life, the concern to antioxidant also is increasing because of its health-promoting effect. Phenolic compounds are one of the plant secondary metabolites class, which shows various benefits to preventing or treating chronic diseases. In this study, we have measured the total phenol content from total 647 rice samples using the Floin-Ciocalteau method, and then were selected 30 rice genetic resources classified with high, middle, and low group on the basis of total phenol content. The average of the total phenol content of each group was high-group ($6892.9{\pm}488.5{\mu}g\;GAE/g$) > middle-group ($1428.1{\pm}76.0{\mu}g\;GAE/g$) > low-group ($97.6{\pm}11.4{\mu}g\;GAE/g$). The selected rice samples were analyzed with LC-MS/MS to find the composition and concentration of individual phenolic in rice grain. High-group and middle-group contained large amounts of protocatechuic acid and (+)-catechin whereas low-group showed limited amount. Among high-group samples, rice samples with black pericarp color (IT 174089, IT 220079, and IT 259958) had high content of peonidin-3-O-glucoside. Further, these black rice samples were special since polydatin, rarely found stilbenoid in rice grain, was detected. Overall, both the sum of phenolic acid and the sum of flavonoid were high-group > middle-group > low-group. Also, each group exhibited different phenolic compositions; high-group consisted of flavonoid more than phenolic acid, middle-group and low-group was comprised of phenolic acid rather than flavonoid, and non-pigmented rice was composed by fully phenolic acid. The total phenol content had positive relationships with the sum of phenolic compound (r = 0.64), the sum of flavonoid (r = 0.74) at the significance level of p < 0.0001. In addition, protocatechuic acid and quercetin showed positive correlation with above phenolic composition parameters; in order, r = 0.98, 0.65 for protocatechuic acid and r = 0.73, 0.78 for quercetin (p < 0.0001). In conclusion, the total phenol content assay showed the possibility of utilization as a phenolic composition indicator in rice grain. Also, this result was suggested study pigment on other material.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.343-370
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• 2023

Developing improved wheat varieties is vital for global food security to meet the rising demand for food. Therefore, assessing the genetic diversity across wheat genotypes is crucial. This study examined the diversity of 168 durum wheat and 47 common wheat collections from 54 different countries using twelve agro-morphological parameters. Geumgang, a prominent Korean common wheat variety, was used as a control. Both qualitative and quantitative agronomical characteristics showed wide variations. Most durum wheats were shown to possess dense spikes (90%), while common wheats showed dense (40%) or loose (38%) spikes, with yellowish-white being the dominant spike color. The majority of the accessions were awned regardless of wheat type, yellowish-white being the main awn color. White or red kernels were produced, with white kernels dominating in both common (74%) and durum (79%) wheats. Days to heading (DH) and days to maturity (DM) were in the ranges of 166-215 and 208-250 days, respectively, while the culm length (CL), spike length (SL), and awn length (AL) were in the ranges of 53.67-163, 5.33-18.67, and 0.50-19.00 cm, respectively. Durum wheats possessed the shortest average DH, DM, and SL, while common wheat had the longest CL and AL (p < 0.05). Common wheats also exhibited the highest average one-thousand-kernel weight. Hierarchical cluster analysis, aided by principal component analysis, grouped the population into seven clusters with significant differences in their quantitative variables (p < 0.05). In conclusion, this research revealed diversity among common and durum wheat genotypes. Notably, 26 durum wheat and 17 common wheat accessions outperformed the control, offering the potential for developing early-maturing, high-yielding, and lodging-resistant wheat varieties.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.705-711
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• 2013

This study was carried out to investigate the effects of the complex fertilizers containing polyaspartic acid (PAA) on growth and $CH_4$ emission in rice field and optimum application rate of the fertilizer compared to the standard recommended application rate (control). The PAA-containing complex fertilizers (PCF) were applied at 55, 65 and 75% levels of standard recommended application rate (control). The application rate of PAA in the plot of every PCF treatment was 150g ai/10a. The PCF was applied as a basal dressing without topdressing at tillering stage. The growth parameters of rice and its nitrogen use efficiency treated with PCF at a 65 to 75% level were not different compared with those of control, and the rice yield was also not significantly different between PCF at a 65 to 75% level and control during 2 years(2010~2011) field experiment. And the $NH_4$-N content in soil was not affected by 65% to 75% level of PCF treatment. Considering overall research results such as rice yield and growth parameters PCF is not significantly different with the control and the optimum application rate of the PCF as a basal fertilization was determined to be 65~75% of the standard application rate based on the result in rice cultivation. Moreover, $CH_4$ emission rate was significantly reduced by PCF treatments, showing 216 kg and 229 kg $CH_4/ha$ at 65% and 75% PCF treatment level, respectively, compared to 266 kg $CH_4/ha$ of the control.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.1
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• pp.40-49
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• 1993

The Objectives of this paper were to develop a modified tank model that is capable of simulating daily streamflow from a small watershed using daily watershed evapotranspiration and to test the applicability of the model to different watersheds. Tank model was restructured to consist of three series of tanks, each of which may mathematically reflect watershed runoff mechanisms from different components of surface runoff, interflow, and baseflow. And pan evaporation was correlated to potential evapotranspiration estimated from a combination method, and was multiplied by monthly crop and landuse coefficients, and watershed storage coefficient to estimate the watershed evapotranspiration losses. Ten watersheds were selected to calibrate model parameters that were defined using an optimization scheme, and the results were correlated with watershed parameters. Simulated daily runoff was compared to the observed ones from the tested watersheds. The simulating results were in good agreement with the observed values when optimal and calibrated parameters were used. Ungaged conditions were also applied to compare simulated values to the observed. And the results were in fair conditions for all the tested watersheds which differ considerably in their sizes, landuse types, and physiological features.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.237-244
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• 2013

Radar remote sensing is appropriate for monitoring rice because the areas where this crop is cultivated are often cloudy and rainy. Especially, Synthetic Aperture Radar (SAR) can acquire remote sensing information with a high temporal resolution in tropical and subtropical regions due to its all-weather capability. This paper analyzes the relationships between backscattering coefficients of rice measured by RADARSAT-2 SAR and growth parameters during a rice growth period. We examined the temporal variations of backscattering coefficients with full polarization. Backscattering coefficients for all polarizations increased until Day Of Year (DOY 222) and then decreased along with Leaf Area Index (LAI), fresh weight, and Vegetation Water Content (VWC). Vertical transmit and Vertical receive polarization (VV)-polarization backscattering coefficients were higher than Horizontal transmit and Horizontal receive polarization (HH)-polarization backscattering coefficients in early rice growth stage and HH-polarization backscattering coefficients were higher than VV-polarization backscattering coefficients after effective tillering stage (DOY 186). Correlation analysis between backscattering coefficients and rice growth parameters revealed that HH-polarization was highly correlated with LAI, fresh weight, and VWC. Based on the observed relationships between backscattering coefficients and variables of cultivation, prediction equations were developed using the HH-polarization backscattering coefficients.

• Journal of Biosystems Engineering
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• v.28 no.1
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• pp.19-26
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• 2003

An oscillating digger mechanism was designed, constructed. and tested. The mechanism is consisted of a six-bar linkage, one four-bar linkage was fer the digger blade and the other one fur variable soil-crop separation. Experimental variables were amplitude(3, 6, 9 mm). frequency(11.2, 14.9. 17.0 Hz), and forward speed of tractor(0.91, 1.13, 1.56 km/h). Each combination of these variables was replicated three times to measure the draft and torque for power requirement evaluation. and the broken-up soil height on the soil separation sieve mechanism. Four parameters λ(the ratio of vibration speed to forward velocity), p(the ratio of vibration acceleration to forward velocity), K(the ratio of vibration acceleration to gravitational acceleration), and T(the product of λ and K) were induced from three experimental variables: amplitude, frequency, and tractor speed. And the power requirement and soil separation ability were analyzed by regression. Though λ and K were known to be the representative parameters. T was the most moderate one to explain draft. torque. and soil separation in this study. It was estimated that the T equal to or greater than 2.4 was the minimum recommended value. Figure 18 would be useful fir the selection of amplitude. frequency, or operating tractor speed once any two variables are known.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.341-351
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• 2002

In order to examine the mechanistic basis for differential sensitivities to chilling and subsequent recovery between two rice (Oryza sativa L.) cutivars, a chilling-tolerant japonica type (Ilpumbyeo) and a chilling-susceptible indica type (Taebaekbyeo), changes of physiological responses and antioxidant enzymes were investigated. Both cultivars at 3 leaf stage were exposed at a low temperature of $5^{\circ}C$ for 3 days and subsequently recovered in a growth chamber at a $25^{\circ}C$ for 5 days with 250 mmol $m^{-2}$ $s^{-1}$. Physiological parameters such as leaf fresh weight, relative water content, cellular leakage, lipid peroxidation, and chlorophyll a fluorescence showed that the chilling tolerant cultivar had a high tolerance during chilling. However, the chilling-susceptible cultivar revealed severe chilling damages. The chilling-tolerant cultivar was also faster in recovery than the chilling-susceptible cultivar in all parameters examined. We analyzed the activity and isozyme profiles of four antioxidant enzymes which are: superoxide dismutase (SOD), caltalase (CAT), ascorbate peroxidase (APX), and glutation reductase (GR). We observed that chilling-tolerance was due to a result of the induced or higher antioxidant enzyme system, CAT and APX in leaves and SOD, CAT, APX, and GR in roots. Especially, we observed the most significant differences between the chilling-tolerant cultivar and -susceptible cultivar in CAT and APX activity. Also in isozyme profiles, CAT and APX band intensity in the chilling-tolerant cultivar was distinctively higher than in the chilling-susceptible cultivars during chilling and recovery. Thus, the cold stability of CAT and APX are expected to contribute to a tolerance mechanism of chilling in rice plants. In addition, the antioxidative enzymes activity in roots may be more important than in that of leaves to protect chilling damage on rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.390-394
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• 2002

Spikelet number per unit area(SPN) is a major determinant of rice yield. Nitrogen nutrition status and biomass during reproductive stage determine the SPN. To formulate a model for estimating SPN, the 93 field experiment data collected from widely different regions with different japonica varieties in Korea and Japan were analyzed for the upper boundary lines of SPN responses to nitrogen nutrition index(NNI), shoot dry weight and shoot nitrogen content at panicle initiation and heading stage. The boundary lines of SPN showed asymptotic responses to all the above parameters(X) and were well fitted to the exponential function of $f(X)=alphacdot{1-etacdotexp(gamma;cdot;X)}$. Excluding the constant, from the boundary line equation, the values of the equation range from 0 to 1 and represent the indices of parameters expressing the degree of influence on SPN. In addition to those indices, the index of shoot dry weight increase during reproductive stage was calculated by directly dividing the shoot dry weight increase by the maximum value ($800 extrm{g/m}^{-2}$) of dry weight increase as it showed linear relationship with SPN. Four indices selected by forward stepwise regression at the stay level of 0.05 were those for NNI ($I_{NNI}_P$) at panicle initiation, NNI($I_{NNI}_h$) and shoot dry weight($I_{DW}_h$) at heading stage, and dry weight increase($I_{DW}$) between those two stages. The following model was obtained: SPN=48683ㆍ $I_{DWH}$$^{0.482}$ㆍ $I_{NNIp}$$^{0.387}$ㆍ $I_{NNIH}$$^{0.318}$ㆍ $I_{DW}$ $^{0.35}$). This model accounted for about 89% of the variation of spikelet number. In conclusion this model could be used for estimating the spikelet number of japonica rice with some confidence in widely different regions and thus, integrated into a rice growth model as a component model for spikelet number estimation.n.n.