• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.42-49
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• 2011

QTL analysis for blast resistance was carried out using 140 $BC_3F_3$ lines derived from a cross between Ilpum as a recurrent parent and Moroberekan as a donor parent. 140 $BC_3F_3$ lines with the parents were inoculated with nine blast isolates. To identify QTLs for resistance to nine blast isolates, 134 SSR markers showing polymorphisms between the parents were genotyped for the 140 $BC_3F_3$ lines. A total of 17 resistance QTLs to nine isolates were detected on chromosomes 2, 3, 4, 6, 7, 9 and 10. The phenotypic variance explained by each QTL ranged from 8.2% to 26.4%. The Moroberekan alleles contributed the positive effect at these 17 QTL loci. In a previous study, the QTL, Pi45(t) for durable resistance to blast was identified using a sequential planting method. To know the relationship between Pi45(t) and the isolate-specific resistance gene, an $F_2$ population was developed from a cross between Ilpum and an introgression line harboring Pi45(t). $F_3$ lines segregating for the Pi45(t) were inoculated to three isolates. $F_3$ lines from the $F_2$ plants with the Moroberekan segment at the target region showed resistance to two isolates. This result seems to indicate that the Pi45(t) and the isolate-specific resistance gene are tightly linked or the resistance is controlled by the same gene(s). The markers linked to genes controlling blast resistance would be useful in developing blast resistance lines in the breeding program.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.447-453
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• 2019

In this study, the effect of supplying volume and frequency of a nutrient solution consisted with $NO_3-N$ 4.6, $NH_4-N$ 3.4, $PO_4-P$ 3, K 3, Ca 4.6 and Mg $2.2mmol{\cdot}L^{-1}$ on growth and fruit quality of 'Duke' blueberry was investigated. Three years old 'Duke' blueberry bushes cultivated in containers ($60{\times}80{\times}40cm$) filled with 130L peat moss and 40L pearlite (v/v) were selected for the experiment. The growth containers were mulched with sawdust. Two different volumes (4L and 8L) of nutrient solution was tested at three different supplying frequencies (one time, two times, and three times) per week and the drainage quality of nutrient solution and fruit quality of 'Duke' blueberry was evaluated. The optimal drainage rate for the vegetable cultivation is known to be 20-30%. The results revealed that the average drainage rates of 27% and 29% for the nutrient solution supplied in 'Duke' blueberry growth medium at 4L, 2 times/7 days and 4L, 3 times/7days, respectively. The highest shoot diameter (4.2mm) and shoot length (31cm) of 'Duke' blueberry was recorded with the 8L of nutrient solution supplied at 3 times per 7 days. According to the analysis of inorganic components in the drainage of nutrient solution, there was a tendency of absorbing nitrogen at the early stage of growth. The supplying volume and frequency of nutrient solution was not significantly affected on 'Duke' blueberry fruit weight, soluble solids content, and titratable acidity. The highest yield per bush (2.7kg) was recorded for the nutrient solution supplied with 4L at three times per 7 days, while the 4L nutrient solution supplied at one time per 7 days resulted the lowest yield of 1.4kg per bush. Consequently, the tested nutrient solution can be applied for the 'Duke' blueberry bushes with the volume of 4L at three times per week for the better crop growth.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.1
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• pp.47-55
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• 1976

This study is conducted to find out potential evapotranspiration values computed by a reasonable formula which is well suited among the existing ones for Suweon area. Each formula based on the data from Suweon Agricultural Meteorological Station during 1964 to 1973. Five formulas which are Blanney-Criddle, Thornthwaite, Penman, Jensen-Haise and Truc have been applied for calculation of potential evapotanspiration. Results obtained are summarized as follows. 1. Potential evapotranspiration of Suweon area shows uni-modal distribution which maximum value occurs in summer and minimum value occurs in winter. Annual potential evapotranspiration computed by Blanney-Criddle formula is 1,377 mm and that computed by others ranges from 714mm to 896mm. 2. Potential evapotranspiration computed by Blanney-Criddle formula is higher value than that computed by others, and among the other formulas it's values show little differences. However, relationships between the former and the mean of four others is highly correlated. 3. In comparison with potential evapotranspiration computed by formulas and actual evapotranspiration for rice paddy which is already reported, value for crop coefficient may be 0.8 in local varities, 1.0 in Tongil varity on Blanney-Criddle formula, and 1.2 in local varities and 1.5 in Tongil varity on the mean of four other fomulas. 4. Five formulas may applied for calculation of potential evapotranspiration because of relatively good correlation among them. However Blanney-Criddle formula is one of recommendable ones, because it is easy to compute and requires less data in compare with other formulas.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.325-335
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• 1985

Biogas production from agricultural wastes were summarized as follows: 1. Biogas Generation Characteristics of Various Manures and Residues a. Gas yield from crop residues like rice straw, rice hull, corn stalk and coconut husk can be improved by addition of animal manures. b. Gas yield from coconut husk can be improved through aerobic fermentation for at least one week before loading in the digester. c. Gas yield from fresh rice straw is better than from pre-fermented one, whether alone or in combination with animal manures. d. Initial study has shown that fresh azolla can be substituted for animal manures in manurerice straw combinations and gas yield derived based on unit volatile solids loaded is actually better than for manure-residue combinations. e. Gas production is highly sensitive to substrate pH and becomes almost nil at a pH of below 6. 2. Effect of ambient conditions and other factors on biogas production in a house hold-size digester. a. Results showed that compaction of rice straw in straw-manure combination can reduce gas yield compared with loosely mixed straw. b. The effective gas production period extended to 70 days using freshly threshed rice straw and fresh cattle manure as feed material. c. Underground and above ground digesters with shade have relatively more stable substrate temperature than aboveground exposed digesters. This relative temperature instability may likely be the reason for lower gas yield for the exposed aboveground digester loaded with loose straw-cattle manure substrate, compared with the underground digester with the same substrate. 3. Economic Analysis a. Based on prevailing costs of fuel, materials, and labor in the Philippines, biogas produced from the household size system is cheaper than either LPG or kerosene. b. If other benefits like organic fertilizer, pollution control and convenience are considered, biogas will surely be the best alternative fuel source.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.13-19
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• 1971

In order to establish the method of improving ill drained paddy soil where the accumulation of absorption inhibitor is worried in the earlier stages of rice growth, proper soil is selected and an field experiment is designed having treatments such as lime materials, none sulfate fertilizers, boron and straw etc. The data of yield and plant analysis in different stages of rice growth is eveluated and discussed to obtain following summaries. (1) Significant yield increase was made by the treatment of lime materials such as slacked lime or wollastonite powder, materials inhibiting the activity of microorganisms such as boron and of none sulfate fertilizers lacking inhibitor producing sources. (2) The crop scientifice causes of decreasing yield are the decreasing the number of panicles per hill, grains per panicle and the weight of grains. (3) The plant nutritional causes of decreasing yield are the lowering of nitrogen content throughout the life, phosphate content since young premodia formation stage of plant and the decreased content of magnesium, calcium and silicate in straw at harvesting stage. (4) The causes of lowering the content of various elements in rice plant grown in ill drained paddy soil are suggested as root damage by producing and accumulating absorption inhibitors such as organic acids and hydrogen sulfide etc, from the following observed facts; (a) In young premodia formation stage, attaining to the maximum production and accumulation of absorption inhibitor, the phosphate accumulation in plant was smaller in the phosphate plots than without phosphate plots and much higher in the neutralized plots by adding lime materials. (b) In the plots of straw addition, the potassium content in plant at the young premodia formation stage is very low probabley due to root damage by absorption inhibitor produced from the process of straw decomposition but higher at the stage of harvesting probably due to the immetabolic negative absorption of damaged roots. (c) The effect of boron, known as the inhibitor of microorganism activity to decompose organic matter, is apparent. (d) The effect of nonsulfate fertilizer treatment, having no source of producing inhibitor such as hydrogen sulfide, was significant. (e) All the yield components, decided around the young premodia formation stage attaining to the maximum inhibitor concentration in soil and minimum root activity, are significantly 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.43 no.6
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• pp.1018-1023
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• 2010

Climatic change was observed and analyzed in view of impacts on agricultural ecosystem, inter alia on rice cropping. The changed climate gave rise to earlier transplanting of rice seedling and later harvest after 40 years. Also phenological change and prolonged growth duration was observed. The meteorological data was selected from the standardized climatological data of 30 year normals of 1960s and 2000s, which were published by Korea Meteorological Administration. Development stages and growing periods of rice crop were compared by analyzing critical and optimum temperatures of each growth stage during these two periods. The first appearance date of $15^{\circ}C$ was ranged from Apr. 29 to May 23 in the year-normals of 1960s and it varied from Apr. 24 to May 16 in the normals of 2000s. The difference of the first appearance date of $15^{\circ}C$ was 0~10 days earlier in the year-normals of 2000s than the 1960s. The last harvesting date was determined to be the last appearance date of mean air temperature $15^{\circ}C$. The difference in the last appearance date of $15^{\circ}C$ was 1 to 13 days later in the year-normals of 2000s than in 1960s. The plant height of a rice variety, Hwayoung-byeo was 101~109 cm in 4 local areas, Seoul, Kangneung, Kwangju and Daegu. The plant height became 1~4 cm taller under warm condition. Rice grain yields estimated with daily weather data for the year-normals of 1960s and 2000s were 453~580 kg $10a^{-1}$ and 409~484 kg $10a^{-1}$ respectively. Rice grain yield of the former period was 50~100 kg $10a^{-1}$ higher than that hat in the later period.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.85-94
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• 2007

To determine the influence of food waste compost (FWC) application on paddy soil, FWC was applied to the paddy soil and then compared with farmer's practice as to the effects on rice and soil environment. Initially, pig manure compost (PMC) had high content of phosphorus ($15g\;kg^{-1}$) and potassium ($23g\;kg^{-1}$), while FWC had high content of total nitrogen ($13g\;kg^{-1}$) and salinity ($18.5g\;kg^{-1}$). Comparison was also made between chemical fertilizer and FWC use as a trial in the paddy field under the clay loam and sandy loam soil. In the panicle formation stage, chemical fertilizer application was proper in clay loam while PMC application was proper in sandy loam. However, chemical fertilizer produced higher yield compared to compost treatment, both on clay loam and sandy loam with 20~25% and 17~19%, respectively. The lower yield in sandy loam maybe due to slow mineralization of compost such that the crop did not effectively use it. Organic matter content in paddy soil after experiment was higher in FWC and PMC plots compared to that in chemical fertilizer plots. But the other soil properties were comparable. Therefore, the FWC compost had little effect on soil when it use as a trial in paddy field. Likewise, after the application of FWC as a trial, analysis of nitrate nitrogen and ammonium nitrogen in the surface water and 60 cm depth of paddy soil water nine days after planting was done. Results revealed that concentration of ammonium nitrogen was similar to irrigation water while nitrate nitrogen concentration was not detected, and hence did not contribute to water pollution. It is concluded that the application of FWC in the paddy field had not affected on environmental pollution in the paddy field. But its use as compost during rice culture reduced yield quantity. Such study should include selection of compost material, amount and method of compost application.

• Korean Journal of Breeding Science
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• v.42 no.1
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• pp.87-99
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• 2010

Genetic diversity and relationships within and among Korean, Japanese and Chinese Jilin provincial wild soybeans based on SSR markers were evaluated to enlarge genetic variation in soybean breeding in the future. A total of 184 wild soybeans including 67 Korean, 71 Japanese and 46 Chinese Jilin provincial wild soybeans were analyzed to evaluate genetic diversity and relationships based on 23 SSR markers. Korean and Japanese wild soybeans were obtained from National Agrobiodiversity Center, Korea, and Biological Resource Center in Lotus and Glycine, Frontier Science Research Center, University of Miyazaki, Japan, respectively. Chinese wild soybeans were collected from Jilin province, China. Twenty three SSR markers generated a total of 964 alleles with an average of 41.9 alleles per marker. Number of alleles ranged from 23 (Satt635) to 56 (Satt157). Genetic diversity (PIC value) of 184 wild soybeans ranged from 0.880 to 0.968 with an average of 0.945. Number of alleles for Korean, Japanese and Chinese Jilin provincial wild soybeans was 513 with an average of 22.3, 511 with an average of 22.2, and 312 with an average of 13.6 per marker, respectively. PIC value for Korean, Japanese and Chinese Jilin provincial wild soybeans was similar with an average of 0.905, 0.897, and 0.850, respectively. Cluster analysis based on genetic distances estimated by SSR markers classified wild soybeans into 3 clusters. Cluster I included only Chinese Jilin provincial wild soybeans. Cluster II included most of Japanese wild soybeans including 5 Korean wild soybeans. Cluster III included most of Korean wild soybeans including 6 Japanese and 1 Chinese Jilin provincial wild soybeans. Cluster I was not subclassified, but cluster II and III were subclassified into various groups. Genetic distance evaluated by SSR markers between Korean and Japanese wild soybeans was closer than that of between Korean and Chinese Jilin provincial, and between Japanese and Chinese Jilin provincial wild soybeans.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.235-242
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• 2018

BACKGROUND: About 81% of nitrous oxide ($N_2O$) emissions from agricultural land to the atmosphere is due to nitrogen (N) fertilizer application. Mitigation of $N_2O$ emissions can be more effective in controlling biochemical processes such as nitrification and denitrification in the soil rather than decreasing fertilizer application. The use of urease inhibitors is an effective way to improve N fertilizer efficiency and reduce $N_2O$ emissions. Several compounds act as urease inhibitors, but N-(n-butyl) thiophosphoric triamide (NBPT) has been used worldwide. METHODS AND RESULTS: Hot pepper and chinese cabbage were cultivated in five treatments: standard fertilizer of nitrogen-phosphorus-potassium(N-P-K, $N-P_2O_5-K_2O$: 22.5-11.2-14.9 kg/ha for hot pepper and $N-P_2O_5-K_2O$: 32.0-7.8-19.8 kg/ha for chinese cabbage), no fertilizer, and NBPT-treated fertilizer of 0.5, 1.0, and 2.0 times of nitrogen basal application rate of the standard fertilizer, respectively in Gyeonggi-do Hwaseong-si for 2 years(2015-2016). According to application of NBPT-treated fertilizer in hot pepper and chinese cabbage, $N_2O$ emission decreased by 19-20% compared to that of the standard fertilizer plot. CONCLUSION: NBPT-treated fertilizer proved that $N_2O$ emissions decreased statistically significant in the same growth conditions as the standard fertilization in the hot pepper and chinese cabbage cultivated fields. It means that NBPT-treated fertilizer can be applied for N fertilizer efficiency and $N_2O$ emissions reduction.