• Journal of Ginseng Research
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• v.40 no.4
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• pp.315-324
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• 2016

Background: Biocontrol agents are regarded as promising and environmental friendly approaches as agrochemicals for phytodiseases that cause serious environmental and health problems. Trichoderma species have been widely used in suppression of soil-borne pathogens. In this study, an endophytic fungus, Trichoderma gamsii YIM PH30019, from healthy Panax notoginseng root was investigated for its biocontrol potential. Methods: In vitro detached healthy roots, and pot and field experiments were used to investigate the pathogenicity and biocontrol efficacy of T. gamsii YIM PH30019 to the host plant. The antagonistic mechanisms against test phytopathogens were analyzed using dual culture, scanning electron microscopy, and volatile organic compounds (VOCs). Tolerance to chemical fertilizers was also tested in a series of concentrations. Results: The results indicated that T. gamsii YIM PH30019 was nonpathogenic to the host, presented appreciable biocontrol efficacy, and could tolerate chemical fertilizer concentrations of up to 20%. T. gamsii YIM PH30019 displayed antagonistic activities against the pathogenic fungi of P. notoginseng via production of VOCs. On the basis of gas chromatography-mass spectrometry, VOCs were identified as dimethyl disulfide, dibenzofuran, methanethiol, ketones, etc., which are effective ingredients for antagonistic activity. T. gamsii YIM PH30019 was able to improve the seedlings' emergence and protect P. notoginseng plants from soil-borne disease in the continuous cropping field tests. Conclusion: The results suggest that the endophytic fungus T. gamsii YIM PH30019 may have a good potential as a biological control agent against notoginseng phytodiseases and can provide a clue to further illuminate the interactions between Trichoderma and phytopathogens.

• Korean Journal of Medicinal Crop Science
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• v.27 no.4
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• pp.271-277
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• 2019

Background: Rehmannia glutinosa (Gaertn.) Libosch. ex Steud. has long been used as a traditional medicinal plant in Korea. This study was carried out to investigate the emergence conditions during the seedling periods in R. glutinosa. Methods and Results: The rhizomes of R. glutinosa variety (Jihwang 1) were harvested in the 22, March, 2018. The rhizomes were sown on in 50-cell plug trays. The emergence rates of seedlings at $15^{\circ}C$, $20^{\circ}C$, $25-40^{\circ}C$, and $45^{\circ}C$ treatment seedling were 1.3%, 96%, 100% and 0%, respectively. Rhizome rot was occurred at the temperature of $15^{\circ}C$ and $45^{\circ}C$. The emergence rates of seedlings in high moisture (HM), moderate moisture (MM) and low moisture (LM) treatments at $35^{\circ}C$ were 99.3%, 100%, and 0%, respectively. Drought damage was recorded in plant with the LM treatment. Seedling quality surveys were carried out at 10-days intervals from 10 to 60 days after sowing (DAS). Leaf length and leaf width were increasing until 50 DAS and the number of leaves was increasing until 60 DAS. Root length was increasing until 40 DAS, and then, flowering occurred from 30 to 60 DAS. Lastly, at 40 DAS, leaf aging and root enlargement was observed. Conclusions: We concluded that the emergence of seedlings was possible in the range of 20 to $40^{\circ}C$. Considering drying and rotting damage, we concluded that the moderate level of moisture is most appropriate for seedling emergence. In addition, we concluded that optimal seedling periods are between 30 and 40 DAS.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.15-19
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• 1974

A severe ginseng root rot disease was occurred and became widespraed in 1973 affecting the ginseng cultivating plot around Kangwha and Gimpo-Gun of Kyunggi province. Soil samples were collected from the area of Wolgot-Myun, Gimpo-Gun, Kuunggi-Do, 1974. We examined general fungi and Fusarium sp. in soil layers and also in different kinds of soil of respective diseased, uncultivated and healthy areas, and found the following results. 1. In the diseased and uncultivated area, the content of moisture, organic matter and silt was greater than in the healthy area. 2. Contray to the above, the healthy area contained a greater amount of inorganic elements such as $P_2O_5$, K,Ca and of soil particle such as Cs and Fs. The degree of pH and content of Mg were even in the three types of soils. 3. General fungi were found in abundance in the diseased and uncultivated soils. It was observed that in all types of areas, general fungi reside in abundance in the rhizosphere, i.e., 10-15cm layers and that the closer the surface, the greater the numbers of fungi. 4. A great number of Fusarium sp. was found in the uncultivated area, and followed diseased and healthy areas. It was observed that in all types of areas, Fusarium sp. distributed in abundance in rhizosphere and that the closer the surface, the greater the numbers of Fusarium sp., with the numbers decreasing as the soil layers increase.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.50-61
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• 1994

From soil samples, 380 antagonistic microorgnisms were isolated. Among the isolates, 42 strains had mycelia growing inhibition ability against Fusariun solani, ginseng root rot causing pathogen. Isolates CHA 1 and S-PFHR 6 were proposed as antagonists for this study and they were identified as Promicromonospora sp. and Pseudomonas pseudoalcaligenes respectively. As an antagonism against hyphae of F. solani in dual culture test, CHA 1 and S-PFHR 6 inhibited linear growing, caused abnormal branching, and the membrane projection which formed by cell wall destruction. The secondary metabolites contained in the culture filtrates which prepared from PD broth and Nutrient broth inhibited the spore germination to 14.3%. The culture filtrate of S-PFHR 6 which prepared by a little amount of soil extract addition to nutrient rich medium had more strongly. inhibited the spore germination and spore germination decreased to less than 4.0% in it. The soil used in this study had fungistasis and the germination rate of macroconidia and chlamydospore of F.solani was 19.4% and 17.7% respectively. The steam sterilized soil lost fungistasis and germination rate of conidia increased to more than 97.9%. The soils amended with the propagule of CHA 1 and S-PFHR 6 increased fungistasis and the germination rate of macroconidia decreased to 14.7% and 11.7% respectively in each treatments. But the soil ammended with glucose and asparagine annulled fungistatic ability and the germination rate of macroconidia increased to more than 48.0%. As an antagonistic activity of the secondary metabolites of two antagonistic isolates in soil, the germination rate of macroconidia of F. solani was 9.3% in the soil amended with the culture filtrate of CHA 1 but the culture filtrate of S-PFHR 6 had no such activity. In the soil which treated with antagonist propagule or culture filtrate, the chlamydospore germination rate was lower than that in natural soil. The addition of glucose and asparagine to antagonist propagule treated soil did not enhanced the chlamydospore germination.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.1
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• pp.24-31
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• 2000

This study was conducted to determine the effect of soil physical characteristics on rhizome rot incidence of platycodon. Sampling sites were Keochang 4, Kimhae 7, Haman 6, Chinju 6 and Koseong 3 fields in Kyongnam province and Hongcheon 6 fields in Kangwon province. The root disease incidence rate was correlated with soil depth Y=-0.747X+88.19($R^2=0.394^{***}$), soil hardness Y=4.36X+8.93($R^2=0.201^*$), bulk density Y=104.7X-80.99($R^2=0.295^{**}$), clay content Y=1.24X+14.14($R^2=0.196^*$), porosity Y=-3.11X+215.9($R^2=0.220^*$) and silt content Y=-0.75X+67.85($R^2=0.178^*$). The yield was correlated with soil depth Y=0.263X+0.971($R^2=0.105^*$), clay content Y=-0.688X+32.74($R^2=0.158^*$), porosity Y=1.974X-93.19($R^2=0.231^{**}$) and silt content Y=53.05X-108.65($R^2=0.232^*$), The optimum cultivated land of perennial platycodon was soil depth over 1m, soil hardness under $5kg\;cm^{-2}$, bulk density $1.0Mg\;m^{-3}$, moisture content 13~17%. clay content 5~10%, porosity 58~63%, silt content 38~64% and soil texture of silt loam.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.134-146
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• 2023

Phytophthora root rot (PRR) is a major soybean disease caused by an oomycete, Phytophthora sojae. PRR can be severe in poorly drained fields or wet soils. The disease management primarily relies on resistance genes called Rps (resistance to P. sojae). This study aimed to identify resistance loci associated with resistance to P. sojae isolate 40468 in Daepung × CheonAl recombinant inbred line (RIL) population. CheonAl is resistant to the isolate, while Daepung is generally susceptible. We genotyped the parents and RIL population via high-throughput single nucleotide polymorphism genotyping and constructed a set of genetic maps. The presence or absence of resistance to P. sojae was evaluated via hypocotyl inoculation technique, and phenotypic distribution fit to a ratio of 1:1 (R:S) (χ² = 0.57, p = 0.75), indicating single gene mediated inheritance. Single-marker association and the linkage analysis identified a highly significant genomic region of 55.9~56.4 megabase pairs on chromosome 18 that explained ~98% of phenotypic variance. Many previous studies have reported several Rps genes in this region, and also it contains nine genes that are annotated to code leucine-rich repeat or serine/threonine kinase within the approximate 500 kilobase pairs interval based on the reference genome database. CheonAl is the first domestic soybean genotype characterized for resistance against P. sojae isolate 40468. Therefore, CheonAl could be a valuable genetic source for breeding resistance to P. sojae.

• Food Science and Preservation
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• v.19 no.2
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• pp.167-172
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• 2012

The antimicrobial activities of $Smilax$ $china$ L. against spoilage bacteria isolated from $Mang-gae$ rice cake were investigated and the storage stability of the $Mang-gae$ rice cake was enhanced. Spoilage bacteria, which cause $Mang-gae$ rice cake to rot, were isolated from commercial $Mang-gae$ rice cake, and most of the isolated strains were identified as $Bacillus$ sp. After the leaves, roots, shoots, and stalks of the $Smilax$ $china$ L. were extracted using 50% ethanol as the solvent, their antimicrobial activities were investigated using the paper disc method by treating them with 50 ${\mu}L$ of $Bacillus$ $cereus$, which is known as a major pathogenic micro-organism in foods that contain starch, as the test organism. The antimicrobial activities of the extracts were compared according to the size of the clear zones around the paper discs. The root extract showed significant antimicrobial activities. When red beans, which are used as stuffing for $Mang-gae$ rice cake, were treated with the root extract of the $Smilax$ $china$ L., the viable cell count of the $Mang-gae$ rice cake was 5.04 Log CFU/g after 48-hr storage, and the cake showed significantly slower growth of bacteria than with commercial products. These results show that treatment of red beans with $Smilax$ $china$ root extract could improve the storage stability of $Mang-gae$ rice cake.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.418-423
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• 2017

In hydroponics, the nutrient solution is supplied considering the water and nutrient uptake characteristics of crops. However, as the ionic uptake characteristics are changed as a result of the weather conditions or the growth response of the crops, the root zone can not be maintained in optimal condition. In addition, the coir substrate has been used mainly for the tomato cultivation in place of the inorganic substrate, there are few studies on long-term cultivation using coir substrate. Therefore, this study was conducted to investigate the effect of EC level of irrigation solution on tomato growth and inorganic ions of root zone in soilless culture using coir. Coir substrate mixed with 5 : 5 chip and dust was used. EC level of irrigation solution was 1.0, 1.5, 2.0, and $3.0dS{\cdot}m^{-1}$. At the initial stage, $NO_3-N$, P, Ca and Mg in the drainage were lower than the irrigation level at 1.0 and $1.5dS{\cdot}m^{-1}$. However, EC $2.0dS{\cdot}m^{-1}$ or higher, all the ions except P were highly concentrated in the drainage. The average fruit weight was not significantly different between 1.0 and $1.5dS{\cdot}m^{-1}$ until 3th cluster, but from the next cluster, the higher the EC level, the smaller the weight. The number of fruit and yield to 6th cluster was the highest at $1.5dS{\cdot}m^{-1}$. From the next cluster, The yield was decreased with the higher EC level. At the early stage of growth, BER occurred only in EC $3.0dS{\cdot}m^{-1}$, but increased in all treatments with increasing irradiation. The incidence rate of EC $3.0dS{\cdot}m^{-1}$ was higher than that of the lower EC level treatment.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.228-235
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• 2012

This study was carried out to investigate the effect of irrigation methods for reducing a drainage on the growth and yield in rockwool (Grodan co.) and cocopeat (chip : dust = 50 : 50 included fiber) culture. The nutrient solution was irrigated by $100J{\cdot}cm^{-2}$-100 mL, $50J{\cdot}cm^{-2}$-45 mL, $50J{\cdot}cm^{-2}$-40 mL, $50J{\cdot}cm^{-2}$-35 mL ($100{\sim}50J{\cdot}cm^{-2}$-100~35 mL, Nutrient solution 100~35 mL was irrigated per plant when the accumulated radiation was $100{\sim}50J{\cdot}cm^{-2}$). The drain rates per plant of 100-100, 50-45, 50-40, 50-35 were 26.3%, 8.8%, 6% 4.4% and 23.1%, 7.5%, 5% 3.4% in rockwool and cocopeat slabs. The water contents and EC of 100-100 and 50-45 were managed by the 55~70%, $3.0{\sim}5.0dS{\cdot}m^{-1}$ which were good condition for paprika culture in rockwool and cocopeat slabs, while those of 50-40 and 50-35 were managed by beyond 50%, $4.5{\sim}9.5dS{\cdot}m^{-1}$. The plant height, number of branches and leaf size of 100-100 and 50-45 were similarly increased while those of 50-40 and 50-35 were decreased. The fruit size and weight of 50-40 and 50-35 were small and light, while those of 100-100 and 50-45 were similarly big and heavy. The marketable fruits of 100-100 and 50-45 treatments were similarly more by 9.7~9.8 in rockwool and 8.8~8.9 in cocopeat, while the unmarketable fruits, the small and blossom end rot fruits were increased in 50-40 and 50-35 treatments. The yield of 100-100 and 50-45 treatments were similarly high.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.27-32
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• 2011

This study was carried out to investigate characteristics of new garlic cultivar 'Alkae' and to identify the effect of scape removal on bulb characteristics and growth of garlic cultivar 'Alkae' and 'Namdo'. Bolting time and harvesting time were earlier about 20 days in 'Alkae' than those in 'Namdo'. 'Alkae' was inferior to 'Namdo' in top growth as plant height, number of leaves, leaf area, SPAD value, diameter of leaf sheath, and so on. but root developing was better in 'Alkae'. Bulb weight of' Alkae' was 17% more than that of 'Namdo', harvested on proper time. The ratio of bulb weight over 40 g was almost double in 'Namdo' as 48% with 'Alkae' as 25%. Occurrence of bulb cracking was more considerable in 'Alkae' and the number of clove per bulb was 1.9 more in 'Alkae' than 'Namdo', but the ratio of bulb rot during storage was higher in 'Namdo' than 'Alkae'. In treatments of scape removal, SPAD value did not show any difference between two cultivars. Leaf dryness was earlier and harder than control and leaf area showed the same tendency as leaf dryness, and there were no significant differences among the methods of scape removal. The bulb weight and the ratio of bulb weight over 40 g at 50 days after the harvest of 'Alkae', 'Namdo' were more 10%, 12% and 27%, 44% in scape removal treatment than control. and there were no significant differences among the methods of scape removal. So, scape removal was very effective to increase large bulb production in the two garlic cultivals and the effect was higher in 'Namdo' than 'Alkae'. The ratio of bulb cracking and the occurrence of bulb rot were almost same in with the scape removal and non removal groups And also there were no significant differences among the methods of scape removal.