• The Plant Pathology Journal
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• v.38 no.2
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• pp.90-101
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• 2022

Pathogenicity of eight Bacillus strains to seedlings of four cotton cultivars was evaluated under greenhouse conditions. Each of the tested cultivars was individually treated with powdered inoculum of each bacterial strain. Untreated seeds were planted as control treatments in autoclaved soil. Effects of the tested strains on levels and activities of some biochemical components of the infected seedlings were also assayed. The biochemical components included total soluble sugars, total soluble proteins, total free amino acids, peroxidase, polyphenol oxidase, phenols, and lipid peroxidation. ANOVA showed that Bacillus strain (B) was a very highly significant source of variation in damping-off and dry weight. Cotton cultivar (V) was a nonsignificant source of variation in damping-off while it was a significant source of variation in dry weight. B × V interaction was a significant source of variation in damping-off and a nonsignificant source of variation in dry weight. Bacillus strain was the most important source of variation as it accounted for 59.36 and 64.99% of the explained (model) variation in damping-off and dry weight, respectively. The lack of significant correlation between levels and activities of the assayed biochemical components and incidence of damping-off clearly demonstrated that these biochemical components were not involved in the pathogenicity of the tested strains. Therefore, it was hypothesized that the pathogenicity of the tested strains could be due to the effect of cell wall degrading enzymes of pathogenic toxins. Based on the results of the present study, Bacillus strains should be considered in studying the etiology of cotton seedling damping-off.

• The Plant Pathology Journal
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• v.37 no.1
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• pp.1-23
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• 2021

Resistance to diseases caused by turnip mosaic virus (TuMV) in crop species of the family Brassicaceae has been studied extensively, especially in members of the genus Brassica. The variation in response observed on resistant and susceptible plants inoculated with different isolates of TuMV is due to a combination of the variation in the plant resistome and the variation in the virus genome. Here, we review the breadth of this variation, both at the level of variation in TuMV sequences, with one eye towards the phylogeny and evolution of the virus, and another eye towards the nature of the various responses observed in susceptible vs. different types of resistance responses. The analyses of the viral genomes allowed comparisons of pathotyped viruses on particular indicator hosts to produce clusters of host types, while the inclusion of phylogeny data and geographic location allowed the formation of the host/geographic cluster groups, the derivation of both of which are presented here. Various studies on resistance determination in particular brassica crops sometimes led to further genetic studies, in many cases to include the mapping of genes, and in some cases to the actual identification of the genes. In addition to summarizing the results from such studies done in brassica crops, as well as in radish and Arabidopsis (the latter as a potential source of candidate genes for brassica and radish), we also summarize work done using nonconventional approaches to obtaining resistance to TuMV.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.264-271
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• 1998

This study was conducted to investigate morphological characteristics of Korean local garlic varieties and to define the genetic variability and the correlations amongthe characters associated with yield. The plant height, the leaf sheath diameter, the nubmer of leaves, and bulb weight were significantly increased in the garlic plants from heavier seed bulbs. The proportation of six clove bulbs was more than 60% in Seosan variety and this was not realted with the number of cloves in seed bulb. While more than 70% bulbs in Jeoksung and Danyang varieties cultivated in paddy field were composed of 6 or 7 cloves, majority of the bulbs of Euisung and Danyang varieties cultivated in upland were composed of bulbs with 7 cloves or more. The highest genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were observed in bulb weight. GCV and PCV also showed high value in leaf sheath diameter. Thus, there is a greater scope for selection of these characters. The small difference between PCV and GCV values in plant height indicates that the environmental influence would be limited in this character. High heritability was observed of plant height (56.76%) and bulb weight (45.95%). And the weight per bulb (34.24%) exhibited highest genitic advance followed by leaf sheath diameter (18.8%) and plant height (9.61%), and those would be the ideal characters for selelction.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.169-174
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• 2012

Quantitative trait loci (QTLs), which were related to the ability of callus induction and plant regeneration in seed culture of rice, were analyzed using a mapping population from a cross between the rice cultivars 'Samgang' (tongil type) and 'Nagdong' (japonica). A tongil type rice cultivar, 'Samgang' showed lower frequency (20%) of plant regeneration than that (35%) of japonica rice, 'Nagdong'. Transgressive segregations were observed for the ability of callus induction and plant regeneration from the seed-derived calli of 58 doubled haploid (DH) lines. The ability of plant regeneration of 58 doubled haploid lines showed a continuous distribution with comparatively wide range (10.0 to 66.7%) of variation. Composite interval mapping analysis was used to identify the QTLs controlling callus induction and plant regeneration ability. Four significant QTLs, qCWS6, qCWS8, qCWS9 and qCWS11, associated with callus weight per seed were detected on chromosomes 6, 8, 9, and 11 with LOD values of 3.30, 2.60, 2.70 and 2.43, explaining 36% of the total phenotypic variation. Three significant QTLs, qPR1, qPR6, and qPR11, for the ability of plant regeneration were located on chromosome 1, 6, and 11 at LOD score of 2.25, 2.15 and 2.55, accounting for 24 % of the total phenotypic variation. The present study should be useful for improving the efficiency of plant regeneration in tissue culture of indica rice by means of marker-assisted selection.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.53-55
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• 2005

The signals of the eddy current testing(ECT) for the examination of the steam generator(SG) tubes in the nuclear power plant(NPP) determine the existence, size, and kind of defects using the variation of impedance signals when a testing coil, driven by alternating current, passes through the SG tube contains defects. The aim of this paper is building a database of the RPC probe signals on the basis of the sizes variation of defects and frequency variation of probe. In this paper 3-D numerical analysis of the ECT signals using the finite element method is performed. Through this study, it is shown variation of magnitude and phase of impedance according to variation of defect size and frequency. From the result of this paper, we can obtain the information which is useful in defect discrimination of SG tube in nuclear power plant.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.48-48
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• 2014

Arbuscular Mycorrhizal Fungi(AMF) is widespread symbiont forming mutualistic relationship with plant root in terrestrial forest in ecosystem. They provide improved absorption of nutrient and water, and enhance the resistance against plant pathogen or polluted soil, therefore AM fungi are important for survival and maintaining of individual or community of plant. For last decade, many studies about the functional variation of AM fungi on host plant growth response were showed that different geographic isolates, even same species, have different effect on host plant. However, little was known about functional variation of AM fungal isolates originated single population, which provide important insight about intraspecific diversity of AMF and their role in forest ecosystem. In this study, four AM fungal isolates of Rhizophagus clarus were cultured in vitro using transformed carrot (Daucus carota) root and they showed the difference between isolates in ontogenic characteristics such as spore density and hyphal length. The plant growth response by mycorrhizas were measured also. After 20 weeks from inoculation of these isolates to host plants, dry weight, Root:Shoot ratio, colonization rates and N, P concentration of host plant showed host plant was affected differently by AM fungal isolates. This results suggest that AM fungi have high diversity in their functionality in intraspecific level, even in same population.

• Plant Resources
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• v.5 no.1
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• pp.17-28
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• 2002

Palynological characters such as pollen grain polar axis length (PL), pollen equatorial diameter (ED), colpus length, colpus width, and P/E ratio of six species of Quercus subgenus Lepidobalanus Endl. from Korea were studied. A significant interspecific variation, unequal distances between the species, and various degree of intraspecific variations were found. The taxonomic value of the pollen morphology parameters measured was found to vary according to species. These results suggest a possible relationship between parameters measured and ploidy level of the Quercus species studied.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.78-83
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• 2008

Soybean [Glycine max (L.)] is a major source of protein for human and animal feed. Inter- and intra-genotype variation of soybean protein has been investigated by soybean researchers. However, limited sample amount of soybean single seed there is no report that investigated intra-plant variation of soybean protein within soybean plant. Recently a non-destructive NIR (near-infrared reflectance) spectroscopy using single seed grain to analyze seed protein was developed. The objectives of this study were to understand variation of seed protein content within plant and to determine the amount of minimum sample size which can represent protein content for a soybean plant. Frequency distribution of protein content within plant showed normal distribution. There was an intra-cultivar variation for protein content in soybean cultivar Seonnogkong. Difference of protein content among single plants of Seonnokong was recognized at 5% level. Seeds in lower position on plant stem tended to accumulate more protein than in higher position. There was significant difference for protein content between sample size 5 seeds and sample size of more than 5 seeds (10, 20, 30, 40, and 50 seeds) at a soybean plant with 57 seeds however no difference was recognized among sample size (5, 10, 20, and 30 seeds) at a soybean plant with 33 seeds. Around 20% seeds of soybean from single plant needed to determine the protein content to represent protein content of single soybean plant. This study is the first one to report evidence of intra-plant variation for proteincontent which detected by non-destructive NIR spectroscopy using single seed grain in soybean.

• Korean Journal of Plant Resources
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• v.23 no.6
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• pp.503-512
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• 2010

Anther derived double haploids (DHs) from sweet pepper genotypes ('Special', 'Derby', 'Bossanova', 'Fiesta', 'Debora' and 'Minipaprika') were used to study the agronomic variation in 2006. Ninety-nine successful DHs regenerants (32 from 'Special', 25 from 'Derby', 23 from 'Bossanova', 10 from 'Fiesta', 6 from 'Debora' and 3 from 'Minipaprika') were transplanted at plastic house and studied on their agronomic characters. Variation in agronomic characters was observed within the DHs of each genotype. DHs obtained from 'Derby' and 'Fiesta' exhibited wide variation in fruit yield $plant^{-1}$ whereas averaged fruit yield $plant^{-1}$ was highest in 'Derby' (1608 g) and less variation was observed in DHs of 'Bossanova'. Based on the agronomic characters expressed in DHs population at this environment, SP55, SP56, SP60, and SP116 from 'Special', SP8, SP10, SP14, SP16, and SP34 from 'Derby', SP115, SP119, SP142, SP143, SP196, and SP199 from 'Bossanova', SP41, SP45, and SP114 from 'Fiesta', SP21 from 'Debora' and SP91 from 'Minipaprika' identified as elite inbred lines and these DH lines could be used for commercial hybrids production in sweet pepper. Genetic relationship among the selected inbred lines using molecular markers and their response to diseases are further recommended to study.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.68-68
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• 2018

A total of 47 core collections of pepper (Capsicum chinense Jacq.) conserved in National Agrobiodiversity Center (NAC) were studied under field condition at Jeonju. 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. Distribution of fruit characters (fruit length, width, and fruit wall thickness) among the accessions was positively skewed. Of the 47 accessions evaluated, 38.3% accessions had conical shaped fruits and mature fruit color was predominantly red (51.1%), orange (21.3%) and yellow (14.9%). Principal component analyses revealed that (i) 56.64% of the qualitative (fruit shape, color and fruit surface) variation and (ii) 89.42% of the quantitative (plant width, height and fruit maturity days) variation were explained by the first two components. Clustering revealed two groups and dendrogram revealed morphological variation among accessions. The phenotypic diversity exists in this core collections provide valuable information to improve agronomic traits in pepper breeding program.