• Korean Journal of Remote Sensing
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• v.25 no.1
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• pp.31-44
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• 2009

The objective of this study was to measure backscattering coefficients of paddy rice using a L-, C-, and X-band scatterometer system with full polarization and various angles during the rice growth period and to relate backscattering coefficients to rice growth parameters. Radar backscattering measurements of paddy rice field using multifrequency (L, C, and X) and full polarization were conducted at an experimental field located in National Academy of Agricultural Science (NAAS), Suwon, Korea. The scatterometer system consists of dual-polarimetric square horn antennas, HP8720D vector network analyzer ($20\;MHz{\sim}20\;GHz$), RF cables, and a personal computer that controls frequency, polarization and data storage. The backscattering coefficients were calculated by applying radar equation for the measured at incidence angles between $20^{\circ}$ and $60^{\circ}$ with $5^{\circ}$ interval for four polarization (HH, VV, HV, VH), respectively. We measured the temporal variations of backscattering coefficients of the rice crop at L-, C-, X-band during a rice growth period. In three bands, VV-polarized backscattering coefficients were higher than hh-polarized backscattering coefficients during rooting stage (mid-June) and HH-polarized backscattering coefficients were higher than VV-, HV/VH-polarized backscattering coefficients after panicle initiation stage (mid-July). Cross polarized backscattering coefficients in X-band increased towards the heading stage (mid-Aug) and thereafter saturated, again increased near the harvesting season. Backscattering coefficients of range at X-band were lower than that of L-, C-band. HH-, VV-polarized ${\sigma}^{\circ}$ steadily increased toward panicle initiation stage and thereafter decreased, and again increased near the harvesting season. We plotted the relationship between backscattering coefficients with L-, C-, X-band and rice growth parameters. Biomass was correlated with L-band hh-polarization at a large incident angle. LAI (Leaf Area Index) was highly correlated with C-band HH- and cross-polarizations. Grain weight was correlated with backscattering coefficients of X-band VV-polarization at a large incidence angle. X-band was sensitive to grain maturity during the post heading stage.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.165-175
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• 1995

To determine the effect of soil moisture stress on growth of barley and grain quality, a pot experiment was carried out for two barley varieties(Olbori and Chogangbori) by using large plastic pot(52cm in diameter and 55cm in depth) filled with sandy loam soil under rain-controlled open green house. By means of measuring soil water potential with micro tensiometer and gypsum block installed at 10cm in soil depth, soil moisture was controlled by sub-irrigation at several irigation points such as -0.05bar, -0.2bar, -0.5bar, -1.0bar, -5.0bar and -10.0bar in soil water potential. The lower soil water potential was controlled, the shorter length of stem and internode became, and the more narrow stem diameter was. Leaf area was significantly decreased when soil water potential was controlled lower than -0.5bar, although chlorophyll content of flag and first leaves was not changed so much. Weight of grain and ear was significantly decreased when soil water potential was lower than -5.0bar and the highest grain yield was obtaind in a plot where soil water potential was controlled at -0.2bar. However, the most efficient water use of Olbori and Chogangbori was obtained at -0.5bar and -1.0bar in water potentials, respectively. Crude protain content, maximum viscosity, consistency and ${\beta}$-glucan content of barley flour increased as soil water potential significantly decreased, especially below -5.0bar, but gelatination temperature decreased as soil water potential decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.878-886
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• 2011

The soybean is one of the oldest cultivated crops in the world. Microwave remote sensing is an important tool because it can penetrate into cloud independent of weather and it can acquire day or night time data. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. In this study, soybean growth parameters and soil moisture were estimated using polarimetric discrimination ratio (PDR) by radar scatterometer. A ground-based polarimetric scatterometer operating at multiple frequencies was used to continuously monitor the soybean growth condition and soil moisture change. It was set up to obtain data automatically every 10 minutes. The temporal trend of the PDR for all bands agreed with the soybean growth data such as fresh weight, Leaf Area Index, Vegetation Water Content, plant height; i.e., increased until about DOY 271 and decreased afterward. Soil moisture lowly related with PDR in all bands during whole growth stage. In contrast, PDR is relative correlated with soil moisture during below LAI 2. We also analyzed the relationship between the PDR of each band and growth data. It was found that L-band PDR is the most correlated with fresh weight (r=0.96), LAI (r=0.91), vegetation water content (r=0.94) and soil moisture (r=0.86). In addition, the relationship between C-, X-band PDR and growth data were moderately correlated ($r{\geq}0.83$) with the exception of the soil moisture. Based on the analysis of the relation between the PDR at L, C, X-band and soybean growth parameters, we predicted the growth parameters and soil moisture using L-band PDR. Overall good agreement has been observed between retrieved growth data and observed growth data. Results from this study show that PDR appear effective to estimate soybean growth parameters and soil moisture.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.779-787
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• 2011

This study was conducted to evaluate the usefulness of ground-based remote sensing for the estimation of rice yield and application rate of N-fertilizer during growing season. Dongjin-1, Korean cultivar of rice was planted on May 30, 2006 and harvested on October 9, 2006. Chlorophyll content and LAI (leaf area index) were measured using Minolta SPAD-502 and AccuPAR model LP-80, respectively. Reflectance indices were determined with passive sensors using sunlight and four types of active sensors using modulated light, respectively. Reflectance indices and growth rate were measured three times from 29 days to 87 days after rice plating and at harvesting day. The result showed that values of growing characteristics and reflectance indices were highly correlated. Growing characteristics to show significant correlation with reflectance indices were in order of followings: fresh weight > N uptake > dry weight > height > No. of tiller > N content. Chlorophyll contents measured by chlorophyll meter (SPAD 502) showed high correlation with nitrogen concentration (r=$0.743^{**}$), although the correlation coefficients between remote sensing data and nitrogen concentration were higher. LAI was highly correlated with dry weight (r=$0.931^{**}$), but relationship between LAI and nitrogen concentration (r=$0.505^*$) was relatively low. The data of CC-passive sensor were negatively correlated with those of the near-infrared. NDVI correlation coefficients found more useful to identify the growth characteristics rather than data from single wavelength. Both passive sensor and active sensor were highly significantly correlated with growth characteristics. Consequently, quantifying the growth characteristics using reflectance indices of ground-based remote sensing could be a useful tool to determine the application rate of N fertilizer non-destructively and in real-time.

• Journal of Bio-Environment Control
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• v.30 no.3
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• pp.237-243
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• 2021

The objective of this study was to evaluate the effect of stem number on plant growth, fruit quality, and yield of sweet peppers grown in greenhouses under supplemental lighting in winter. The seedlings were transplanted at 3.2 plants·m^-2 on October 26, 2020, and started supplemental lighting with 32 high pressure sodium lamps for 16-hour photoperiod from December 1, 2020 to May 25, 2021. Stems were differently trained with 2 and 3 numbers after branching nodes were developed. In the final harvest, the plant height was significantly shorter in the 3 stem-plants than in the 2 stem-plants. The number of nodes per stem and the leaves per plant were increased in the 3 stem-plants than in the 2 stem-plants, while the leaf area was less affected. There were no significant differences in the dry mass of leaves, stems, and immature fruits between the 2 and 3 stem-plants. The fruit fresh weight and fruit dry weight in the 3 stem-plants were decreased by 17% and 12% at 156 days after transplanting (DAT), and by 17% and 15% at 198 DAT compared to those in the 2 stem-plants, respectively. The marketable fruit rates were 93.6% and 95.4% in the 2 and 3 stem-plants, respectively. The total fruit yield in the 3 stem-plants was increased by 30.2% as compared to that in the 2 stem-plants. We concluded that the 3-stem-training cultivation positively affected the total fruit yield by sustaining adaptive vegetative growth of the plants. This result will help producers make useful decisions for increasing productivity of sweet peppers in greenhouses.

• Korean Journal of Breeding Science
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• v.49 no.3
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• pp.235-244
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• 2017

'Manbaek' is a bacterial blight resistant mid-late maturing rice cultivar with high grain quality. 'Manbeak' was derived from anther culture using the backcross combination, $Hopum^*2/SR30075$. 'Hopum' is a mid-late maturing rice cultivar with high grain quality and 'SR30075' is a pyramid line carrying three bacterial blight resistance genes. 'Manbaek' was selected through the pedigree method, yield trials, and local adaptability tests. 'Manbeak' carrying two bacterial blight resistance gene Xa3 and xa5 showed high-level and broad-spectrum resistance against bacterial blight. 'Manbaek' was resistant to K3a, mostly virulent race in Korea, and exhibited resistance reaction against 16 Korean bacterial blight isolates. 'Manbaek' was a mid-late maturing rice. The heading date of 'Manbaek' was August 19th, which was 5 days later than that of 'Nampyeong'. Manbaek' was a lodging-tolerant rice with short culm and dark green leaf. Due to the low viviparous germination, 'Manbaek' could be a useful material to prevent pre-harvest sprouting. 'Mabeak' was resistant to bacterial blight and rice stripe virus, but susceptible to other virus diseases and insect pests. The yield of 'Manbaek' was similar to 'Nampyeong'. 'Manbaek' showed excellent grain appearance and good tastes of cooked rice, so that it could contribute to improving the quality of bacterial blight resistant cultivars. 'Manbaek', bacterial blight resistant cultivar with high grain quality, is suitable for the cultivation at bacterial blight prone area and has been utilized in the breeding programs for enhancing the resistance against bacterial blight (Registration No. 6069).

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.302-306
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• 2010

'Migwang' is a new japonica rice variety developed from a cross between SR15926-10-2-3-3-3 having a good canopy architecture and multiple disease resistance, and Iksan431 having a translucent milled rice and good eating-quality with a view of developing a new variety having multiple disease resistance by the rice breeding team at NICS, RDA in 2009. The heading date of this variety is August 15 and later than check variety, Hwaseongbyeo, by four days. 'Migwang' has 75 cm of culm length and 98 spikelets per panicle. This variety showed longer heading delay and higher spikelet sterility than those of Hwaseongbyeo while exposed to cold stress. This variety showed resistance to blast disease and bacterial leaf blight, but susceptible to rice stripe virus and planthoppers. The milled rice of this variety exhibits translucent, clear non-glutinous endosperm and short grain shape. 'Migwang' has better palatability index of cooked rice than that of Hwaseongbyeo. The whole grain rate of milled rice and milled rice recovery of 'Migwang' are higher than those of Hwaseongbyeo as 96.8% and 73.1%, respectively. 'Migwang' has 5.5 MT/ha in milled rice. 'Migwang' could be adaptable to the middle plain area, mid-western and southeastern costal areas and mid-mountainous areas in Korea.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.600-605
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• 2010

'Dagreen' (Scale cereal L.), a new rye variety was developed from the open pollination among 10 rye lines at the National Institute of Crop Science in 1995 and mass selection were made at National Institute of Crop Science from 1996 to 1999. Recurrent selections were made at Dept. Rice and Winter Cereal Crop, NICS, RDA from 2000 to 2006. This new variety has erect plant type with medium size pale green leaves. The number of spike per $m^2$ was 713 and the plant height was 103cm. The heading date of 'Dagreen' was April 24 which was 7 days earlier than that of "Koolgrazer". It was adaptable for forage use at an early stage as a whole crop. Lodging resistance was higher than that of check variety 'Koolgrazer'. The chemical components and quality of forage showed 10.2 % crude protein, 36.6 % ADF, 62.4 % NDF and 59.9 % TDN. 'Dagreen' showed high resistance to powdery mildew and leaf rust than those of check variety in the field condition. The average dry matter (7,010kg $ha^{-1}$) of 'Dagreen' harvested at April 28 were 6 % higher than 'Koolgrazer'. This variety is recommended for all of the rye cultivation area in Korea.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.600-605
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• 2011

'Boseogheugchal', a new black pericarp glutinous rice cultivar (Oriza sativa L.), was developed by the rice breeding team of National Institute of Crop Science, RDA, Suwon, Korea during the period from 1997 to 2008 and released in 2008. It was derived from a cross between SR18638-B-B-B-18-2/ Heugmi H31. The maturity of this cultivar is about 135 days from seedling to heading. This cultivar has about 12 tillers per hill and 94 spikelet numbers per panicle. Ripening ratio is about 72% and 1000 grain weight is 21.6 g in brown rice. This new variety shows grain shattering resistance and susceptible for blast, bacterial leaf blight and stripe virus. 'Boseogheugchal' has glutinous endosperm and low protein contents. It has higher anthocyanin content compared to black pigmented check cultivar 'Hegjinjubyeo'. The yield performance of brown rice was 4.82 MT/ha in local adaptability test for three years. 'Boseogheugchal' is adaptable to central plain area of Korea.

• Korean Journal of Breeding Science
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• v.43 no.3
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• pp.190-195
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• 2011

'Youho' (Hordeum vulgare L.), a new ruminant-palatable forage barley cultivar, was developed by the breeding team at the Department of Rice and Winter Cereal Crop, National Institute of Crop Science, RDA in 2008. It was derived from the cross between 'Suwon339' and 'Suwon355'. Among the cross made in 1999, a promising line, SB992047-B-B-B-6-2, showed good characteristics in potential forage yield in the yield trial tested at Iksan from 2005 to 2006. In 2007, it was designated as 'Iksan431' and placed in regional yield trials at eight locations in Korea for two years from 2007 to 2008, and was released as the name of 'Youho'. It has the growth habit of group II, erect plant type, green leaf and hood spike. Its average heading and maturing dates were on Apr. 24 and May 26, respectively, which are similar to check cultivar 'Yuyeon'. 'Youho' also showed weaker winter hardiness, but better resistance to lodging, shattering and BaYMV than those of check cultivar. It showed higher crude protein content, grade of silage quality than those of check cultivar. The average forage dry matter yield in the regional yield trial was about 14.1, $10.9MT\;ha^{-1}$ in upland and paddy field, respectively, which were 1% to 4% lower than that of the check cultivar. This cultivar would be suitable for the area whose daily minimum temperature was above $-8^{\circ}C$ in January in Korean peninsula.