• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.296-313
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• 1982

At a time when world population and food supply are in a delicate balance, it is essential that we look at factors to improve this balance. We can alter the environment to better fit the plant's needs, or we can alter the plant to better fit the environment. Improved technology has allowed us to increase the yield level. For moderately detrimental weather events technology has generally decreased the yield variation, yet for major weather disasters the variation has increased. We have raised the upper level, but zero is still the bottom level. As we concentrate the production of particular crops into limited areas where the environment is closest to optimum, we may be increasing the risk of a major weather related disaster. We need to evaluate the degree of variability of different crops, and how weather and technology can interact to affect it. The natural limits of crop production are imposed by important ecological factors. Production is a function of the climate, the soil, and the crop and all activities related to them. In looking at the environment of a crop we must recognize these are individuals, populations and ecosystems. Under intensive agriculture we try to limit the competition to one desired species. The environment is made up of a complex of factors; radiation, moisture, temperature and wind, among others. Plant response to the environment is due to the interaction of all of these factors, yet in attempting to understand them we often examine each factor individually. Variation in crop yields is primarily a function of limiting environmental parameters. Various weather parameters will be discussed, with emphasis placed on how they impact on crop production. Although solar radiation is a driving force in crop production, it often shows little relationship to yield variation. Water may enter into crop production as both a limiting and excessive factor. The effects of moisture deficiency have received much more attention than moisture excess. In many areas of the world, a very significant portion of yield variation is due to variation in the moisture factor. Temperature imposes limits on where crops can be grown, and the type of crop that can be grown in an area. High temperature effects are often combined with deficient moisture effects. Cool temperatures determine the limits in which crops can be grown. Growing degree units, or heat accumulations, have often been used as a means of explaining many temperature effects. Methods for explaining chilling effects are more limited.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.1
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• pp.18-24
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• 1989

The effect of soil physico-chemical properties of pre and post soil preparation and permanent bed period on growth and yield was analysed by two models of annual variation and percent annual change (PAC). 1. Aggregation, porosity, bulk density except moisture were significantly different in each year from preparation to the 6th year while all soil chemical properties except Mg were significantly different in each year. 2. Soil physical properties showed significant simple correlation with yield and negative with the missing plant rate in each year while the electroconductivity ($EC_5$) of the 4th year showed significant correlation with yield. 3. Yield showed significant positive correlation with the variation of aggregation in permanent bed period, and negative with variation and PAC of aggregation of preplanting soil and variation of moisture in permanent bed period. Missing plant rate was negatively correlated with porosity variation of preplanting soil and positively with PAC of aggregation in preplanting soil and of moisture in permanent bed period. 4. According to multiple regression between yield and soil physical properties, porosity of preplanting soil was in the greatest contribution. Among aggregations, the variation in permanent bed period was in the greatest contribution.

• Korean Journal of Plant Resources
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• v.16 no.1
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• pp.55-60
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• 2003

The genetic variation of random amplified polymorphic DNA (RAPD) patterns of genomic DNAs was investigated in dioecious plant Rumex acetosa L., which carries different sex chromosome complements in female (2n=12A+XX) and male (2n=12A+XY$_1$Y$_2$). One hundred and twenty random primers consisted of 10-mer were used for PCR amplification. Polymorphic bands were found in 24 primers. Specific bands for female and male were 16 and 18, respectively. Especially, a band of 1,440 bp from the OPC-10 primer was male specific. These sex specific RAPD markers are used to understanding the sex determination mechanism in plants.

• 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.

• Journal of Biosystems Engineering
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• v.31 no.3 s.116
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• pp.188-193
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• 2006

Elevation differences within a paddy field relate strongly to plant health, crop homogeneity, and pest control. For precision agriculture (PA), the elevation within a field should be precisely controlled. We analyzed variation in elevation within a rice paddy field over one crop cycle. The study took place in a rectangular plot (100 m x 30 m). Elevations within the a plots was measured by a laser-equipped surveying instrument, that could determine elevations to precisions of I mm. The test field was divided into grids with 30 squares; elevation was measured at the center of each 5 x 10-m grid square. This study measured elevation during nine observation periods from pre-plowing to post-harvest. Descriptive statistics showed the highest elevations after plowing due to soil disturbance. One-way analysis of variance (ANOVA) revealed significant elevation differences before and after plowing and transplanting, although elevations were similar over the period of crop growth. Comparison of pre-plowing and post-harvest data showed differences in elevations, indicating that elevation changes occurred during plowing, rice transplanting, plant growth, and harvesting. In summary, the above statistical analysis indicated that elevation changes occurred due to plowing but not during the plant growth season or due to harvesting.

• Plant Resources
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• v.3 no.3
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• pp.211-218
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• 2000

Intraspecific genetic relationship of 19 variation types of the Yam (Dioscorea alata) classified by their external morphological characteristics such as leaf and tuber shape were assessed by DNA using random and specific primer. Twenty two out of 113 primers (100 random[10-mer] primers, two 15 mer [M13 core sequence, and (GGAT)$_4$ sequence]) had been used in PCR-amplification. Only 12 primers, however, were success in DNA amplification in all of the analyzed plants, resulting in 93 randomly and specifically amplified DNA fragments. The analyzed taxa showed very high polymorphisms(69 bands, 71.0 %), allowing individual taxon to be identified based on DNA fingerprinting. Monomorphic bands among total amplified DNA bands of each primer was low under the 50%. Similarity indices between accessions were computed from PCR(polymerase chain reaction) data, and genetic relationships among intraspecific variations were closely related at the levels ranging from 0.66 to 0.90. These DNA data were not matched well with those of morphological characters since they were divided into two major groups at the similarity coefficient value of 0.70. Therefore, Grouping of species into variation types by mainly morphological charactistics was suggested unreasonable.

• Korean Journal of Plant Resources
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• v.27 no.3
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• pp.249-255
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• 2014

The rice belonging to Oryza sativa is not only has significant economic importance, for it is the major source of nutrition for about 3 billion all around the world. But also plays a vital role as a model organism, because it has a number of advantages to be a model plant, such as efficient transformation system and small genome size. Many methods and techniques have been conducted to attempt to distinguish different Oryza sativa species, such as amplified fragment length polymorphism (AFLP), random amplified polymorphic DNA (RAPD), simple sequence repeat (SSR) and so on. However, studies using sequence analysis of internal transcribed spacer (ITS), a region of ribosomal RNA has not been reported until now. This study was undertaken with an aim to understand the phylogenetic relationships among sixteen isolates of Oryza sativa collected from abroad and fifteen isolates collected from Korea, using ribosomal RNA (rRNA) internal transcribed spacer (ITS) sequences to compare the phylogeny relationships among different Oryza sativa species. The size variation obtained among sequenced nuclear ribosomal DNA (nrDNA) ITS region ranged from 515bp to 1000bp. The highest interspecific genetic distance (GD) was found between Sfejare 45 (FR12) and Anapuruna (FR15). Taebong isolate showed the least dissimilarity of the ITS region sequence with other thirty isolates. This consequence will help us further understanding molecular diversification in intra-species population and their phylogenetic analysis.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.370-378
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• 2010

This review describes the stratagies of development of virus-resistant Alstroemeria plants using the genetic modification system. Despite of increasing of its importance in cut flower market, improvements of some horticultuirally important traits such as fragrance, long vase-life, virus resistance and tolerance against abiotic stresses are lack of the breeding program in Alstroemeria. Of these traits, virus-resistance is quite difficult to develop in Alstroemeria plants due to the limitations of genetic variation in the existed germplasm. To extend the genetic variation, plant biotechnological techniques such as genetic transformation and tissue culture should be combined to develop virus-resistant line in Alstroemeria. In this review, several strategies for the generation of virus-resistance by using natural resistance genes, pathogen-derived genes and other sources including pathogen-derived proteins, virus-specific antibodies and ribosome-inactivating proteins are presented. Also, brief histories of breeding, tissue culture, and transformation system in Alstroemeria plants are described to inderstand of the application of transgenic approach for the development of virus-resistance in Alstroemeria species.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.3
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• pp.198-204
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• 2003

A basic experiment was performed to control tile plant growth using acoustic emission technique considering the environmental conditions for plant. At a dry soil condition, the signals due to the cavitation from xylem of angiosperm and gymnosperm were mainly detected. The strong signal from xylem and the weak signal from plasmodesmata and casparian strip were detected at the same time after distilled water was provided. Two signals after providing tile acid and distilled water were contrary to each other. The wind, number of leaf, music, temperature and humidity affected the acoustic emission count from plants but the frequency ranges of the detected signals were the same.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.38-38
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• 2019

Among the 6500 accessions of the pepper germplasm which conserved at RDA Genebank, 319 accessions were investigated charateristics such as their growth habit, flowering and fruit shape in Capsicum frutescens. All accessions were characterized for their 14 qualitative and 16 quantitative characters. Results revealed that both qualitative and quantitative characters exhibited wide variation among the studied germplasm. The hypocotyl color, which investigated in juvenile stage, was divided in three types such as green, purple, and purple with green, and most of the accessions showed in purple. Flowering starts from 7 May, and most accessions were starting to flower from 27 May to 25 June. The fresh color of the mature pepper were red, yellow, orange, Etc. Fruit shape were mostly elongated, while exhibited ball shape and round shape were a few. The fresh weight of fruits ranged from 0.2 to 42.3, and the diameter of fruit showed from 4.2 to 45.1 mm, respectively. The phenotypic diversity exists in Capsicum frutescens. provide valuable information to improve agronomic traits in pepper breeding program.