• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.335-340
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• 1996

A green house experiment was conducted to investigate the growth of Chinese cabbage, radish and soybean and change in the chemical properties of the soil after the 10mm application of the simulated acid rain(SAR) of pH 2.7 in the form of sprinkle and mist. It was applied 30 times for Chinese cabbage and radish and 62 times for soybean at the two-day intervals. The results obtained are summarized as follows: 1. Visual damages caused by SAR were dark-brown or red brown leaf spots in Chinese cabbage, and dark-brown and wrinkled leaf margins in radish and soybean. 2. The degree of visual damages became severer as the number of SAR applications increased and it was severer with mist than with sprinkle of SAR. 3. Chlorophyll content was reduced by SAR, but it was not affected by the form of SAR application(sprinkle or mist) in all crops, although it was slightly lower with mist than with sprinkle of SAR. 4. Fresh weight of Chinese cabbage heads and radish roots and grain yield of soybean were reduced by SAR, and were not affected by the form of SAR application. 5. Contents of K, Ca, and Mg in leaves were reduced, while S content increased by SAR in all crops. The forms of SAR application did not affect contents of mineral nutrients in all crops. 6. SAR decreased soil pH and the contents Ca, Mg, and K of soil, while increased $SO_4$ content. However, the contents of soil organic matter, N, and P were not affected by SAR. Forms of SAR application did not affect soil chemical properties either.

• Journal of the Korean Geographical Society
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• v.51 no.5
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• pp.633-649
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• 2016

Exposure to high temperatures during the reproductive period of crops decreases their productivity. The Intergovernmental Panel on Climate Change's (IPCC) fifth Assessment Report predicts that the frequency of high temperatures will continue to increase in the future, resulting in significant impacts on the world's food supply. This study evaluate climate change-induced heat stress on four major agricultural crops (rice, maize, soybean, and wheat) at a global level, using the coupled atmosphere-ocean model of Hadley Centre Global Environmental Model version 2 (HadGEM2-AO) and FAO/IIASA Global Agro-Ecological Zone (GAEZ) model data. The maximum temperature rise ($1.8-3.5^{\circ}C$) during the thermal-sensitive period (TSP) from the baseline (1961-1990) to the future (2070-2090) is expected to be larger under a Representative Concentration Pathway (RCP) 8.5 climate scenario than under a RCP2.6 climate scenario, with substantial heat stress-related damage to productivity. In particular, heat stress is expected to cause severe damage to crop production regions located between 30 and $50^{\circ}N$ in the Northern Hemisphere. According to the RCP8.5 scenario, approximately 20% of the total cultivation area for all crops will experience unprecedented, extreme heat stress in the future. Adverse effects on the productivity of rice and soybean are expected to be particularly severe in North America. In Korea, grain demands are heavily dependent on imports, with the share of imports from the U.S. at a particularly high level today. Hence, it is necessary to conduct continuous prediction on food security level following the climate change, as well as to develop adaptation strategy and proper agricultural policy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.269-273
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• 2006

The study of molecular markers to improve crops largely depends on the availability of rapid and of efficient DNA extraction methods. Here we developed a cheap and convenient method to isolate genomic DNA from rice grains suitable for large-scale microsatellite analysis. We confirmed that the isolated rice DNA is suitable for PCR analysis with STS marker and SNP marker, as well as microsatellite marker. Further, we established high-throughput DNA extraction system in a 96-well plate format which make it possible high-throughput analysis of microsatellite markers with rice grains. This implies that the new method could be a useful tool for other types of marker analysis in large scale.

• Journal of Plant Biology
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• v.13 no.2
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• pp.21-31
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• 1970

The rice variety, Nongkwang was used in two factorial experiments with the combination of 15 kg and 20 kg of N per 10 a, 3 levels of P2O5 (0, 4 and 8 kg per 10 a) and 4 levels of potash(0, 2, 4 and 8 kg per 10 a) in the reclaimed soil areas containing 0.48% on the average salt content throughout the year(0.67% at the end of April). The absorption of N, K and Ca was accelerated by increased N applications. The absorption of P itself was not enhanced by the increased application of P2O5 but the absorption of K2O reduced the absorption of Mg was affected. The increased application of K2O reduced the absorption of Si and seemed to increase the content of carbohydrate in the rice plants. Twenty kg of N and 4kg of P2O5 per 10 a produced satisfactory yields of rough rice, potash applications are ineffective in this experiment on rice grain production.

• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.185-191
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• 2013

Over the past decades, carbon dioxide concentration of the atmosphere of the world has increased significantly, and thereby the greenhouse effect has become a social issue. To solve this problem, new renewable energy sources including solar, hydrogen, geothermal, wind and bio-energy are suggested as alternatives. Among these new energy sources, bio-energy crops are widely introduced and under rapid progress. For example, corn and oilseed rape plants are used for the production of bio-ethanol and bio-diesel, respectively. However, grain prices has increased severely because of the use of corn for bio-ethanol production. Therefore, non-edible switchgrass draws attention as an alternative source for bio-ethanol production in USA. This review describes the shortage of fossil energy and an importance of switchgrass as a bio-energy crop. Also, some characteristics of its major cultivars are introduced including growth habit, total output of biomass yields. Furthermore, biotechnological approaches have been conducted to improve the productivity of switchgrass using tissue culture and genetic transformation.

• KCID journal
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• v.19 no.1
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• pp.50-63
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• 2012

Many reclaimed tideland projects in Korea have been conducted to secure the food self-sufficiency. In fact, the domestic food self-sufficiency has been greatly improved and reclaimed tideland projects contribute to Korea's economic and social development directly or indirectly replacing agricultural lands from urbanization, industrialization. As result, current self-sufficiency of rice reach the demand(104.6%) while rate of upland crops has less than 30% of self-sufficiency rate and corn, wheat, soybeans, etc. are virtually dependent on imports. Domestic price of crop is expected to be unstable by trend of international grain prices. Therefore, developing reclaimed tidelands as upland which is originally constructed for paddy fields could be a good option to become steady in domestic crop market and dedicate to ensure a stable food security. The study to prepare measures for dealing with disasters in reclaimed tidelands of west coast district is required in order to utilize those sites for infra construction of multi-utilization in those sites and The result of flooding analysis in this study can suggest policy direction for practical utilization of reclaimed tidelands in yellow sea area.

• Korean Journal of Remote Sensing
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• v.28 no.6
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• pp.653-660
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• 2012

This study classified paddy fields according to rice varieties and monitored temporal changes in rice growth using SAR backscatter coefficients (${\sigma}^{\circ}$). A growing period time-series of backscatter coefficients was set up for nine fine-beam mode RADARSAT-1 SAR images from April to October 2005. The images were compared with field-measured rice growth parameters such as leaf area index (LAI), plant height, fresh and dry biomass, and water content in grain and plants for 45 parcels in Dangjin-gun, Chungnam Province, South Korea. The average backscatter coefficients for early-maturing rice varieties (13 parcels) ranged from -18.17 dB to -6.06 dB and were lower than those for medium-late maturing rice varieties during most of the growing season. Both crops showed the highest backscatter coefficient values at the heading stage (late July) for early-maturing rice, and the difference was greatest before harvest for early-maturing rice. The temporal difference in backscatter coefficients between rice varieties may play a key role in identifying early-maturing rice fields. On the other hand, comparisons with field-measured parameters of rice growth showed that backscatter coefficients decreased or remained on a plateau after the heading stage, even though the growth of the rice canopy had advanced.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.1-11
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• 2016

Single nucleotide polymorphism (SNP) is an abundant form of genetic variation within individuals of species. DNA polymorphism can arise throughout the whole genome at different frequencies in different species. SNP may cause phenotypic diversity among individuals, such as individuals with different color of plants or fruits, fruit size, ripening, flowering time adaptation, quality of crops, grain yields, or tolerance to various abiotic and biotic factors. SNP may result in changes in amino acids in the exon of a gene (asynonymous). SNP can also be silent (present in coding region but synonymous). It may simply occur in the noncoding regions without having any effect. SNP may influence the promoter activity for gene expression and finally produce functional protein through transcription. Therefore, the identification of functional SNP in genes and analysis of their effects on phenotype may lead to better understanding of their impact on gene function for varietal improvement. In this mini-review, we focused on evidences revealing the role of functional SNPs in genes and their phenotypic effects for the purpose of crop improvements.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.228-237
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• 1996

On the basis of a brief introduction of the mechanized dry farming in Heilongjiang Province, the author states the developing process from the combination of single technics of farm machinery and agronomy to the technical assembly of high yield cultivation technics and its mathematical expression. According to the main temperature accumulated zones, 5 typical comprehensive technical assembly models for the mechanized cultivation technics and their agricultural machinery systems have been listed. They are, the Heihe " 261" wheat and soybean model : the Yi'an big ridge double row film mulching corn model : the Yongchang high yield mechanized soybean and other grain crops six year rotation model for Keshan state farms. The author conclude that the application of mechanized high yield cultivation technical assembly is the key point to transform the Heilongjiang province from big agriculture to strong agriculture, we have to take " high yield , high quality , high efficiency , s stain -ability and earning foreign currency" as the general target and carry out the corresponding policy and measures for the further development of agricuture.

• Korean Journal of Breeding Science
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• v.40 no.2
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• pp.101-105
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• 2008

The germplasm of 246 rice cultivars was analysed for iron and zinc contents using a Inductively Coupled Argon Plasma (ICP) at International Rice Research Institute (IRRI) Philippines. Iron contents ranged from 2.0 to 12.0, and zinc ranged from 10.0 to 33.0 (mg/kg), showing with the mean values of 4.3 and 22.8 (mg/kg), respectively. In genotypes tested, there was approximately a two-fold difference in iron and zinc concentrations, suggesting a genetic potential to increase these micronutrients in rice grain. A highly significant positive correlation ($r^2=0.503$) was found between iron and zinc contents. Iron contents decreased drastically as polishing time increased, whereas zinc decreased only slightly. In the interaction between genotype and environment on iron contents, genotype (G), environment (E), and the G ${\times}$ E interactions accounted for 69%, 5% and 26% of the sums of squares, respectively. Indicating that genotype is would be the most significant factor for the to improve iron contents of rice in rice breeding, suggesting that therefore identifying genotypes with relatively stable performance across various environments is important as staple food crops.