• Journal of Ginseng Research
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• v.42 no.2
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• pp.208-217
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• 2018

Background: The quality differences in seedlings of medicinal herbs often affect the quality of medicinal parts. The establishment of the grading standard of Panax notoginseng seedlings is significant for the stable quality of medicinal parts of P. notoginseng. Methods: To establish the grading standard of P. notoginseng seedlings, a total of 36,000 P. notoginseng seedlings were collected from 30 producing areas, of which the fresh weight, root length, root diameter, bud length, bud diameter, and rootlet number were measured. The K-means clustering method was applied to grade seedlings and establish the grading standard. Results: The fresh weight and rootlet number of P. notoginseng seedlings were determined as the final indices of grading. P. notoginseng seedlings from different regions of Yunnan could be preliminarily classified into four grades: the special grade, the premium grade, the standard grade, and culled seedlings. Conclusion: The grading standard was proven to be reasonable according to the agronomic characters, emergence rate, and photosynthetic efficiency of seedlings after transplantation, and the yields and contents of active constituents of the medicinal parts from different grades of seedlings.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.344-352
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• 2019

Drought stress caused by global climate change is a serious problem for rice cultivation. Increasingly frequent abnormal weather occurrences could include severe drought, which could cause water stress to rice during the seedling stage. This experiment was conducted to clarify the effects of drought during the seedling period on yield and quality of rice. Drought conditions were created in a rain shelter house facility. The drought treatment was conducted at 3, 10, and 20 days after transplanting. Soil water content was measured by a soil moisture sensor during the whole growth stage. In this study, we have chosen 3 rice cultivars which are widely cultivated in Korea: 'Haedamssal' (Early maturing), 'Samkwang' (Medium maturing), and 'Saenuri' (Mid-late maturing). The decrease in yield due to drought treatment was most severe 3 days after transplanting because of the decrease in the number of effective tillers. The decrease in grain quality due to drought treatment was also most severe 3 days after transplanting because of the increased protein content and hardness of the grains. The cultivar 'Haedamssal' was the most severely damaged by water stress, resulting in about a 30% yield loss. Drought conditions diminished the early vigorous growth period and days to heading in early-maturing cultivars. The results show that drought stress affects yield components immediately after transplanting, which is a decisive factor in reducing yield and grain quality. This study can be used as basic data to calculate damage compensation for drought damage on actual rice farms.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.335-340
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• 2013

This research was conducted to know the appropriate leaf number of scion for tube grafting in context with survival rate and quality of seedlings, and early yield of $1^{st}$ and $2^{nd}$ cluster of cherry tomato plants. Scions were grafted when having leaves 1~2 (LF-2), 2~3 (LF-3), or 3~4 (LF-4). The treatment LF-3 showed the highest survival rates and the best results in 6 factors among 12 seedling quality factors. In case of early yield, the treatment LF-2 showed higher yield than others with the big difference. Economic analysis showed that LF-3 is desirable in case of nursery while LF-2 is better in case of farmers. The compromising solution is that farmers buy a little expensive seedlings grafted at the leaf stage of 1~2 from nurseries in terms of win/win strategy.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.101-107
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• 2007

This experiment was carried out to develop the substrate mixtures for the production of high quality plug seedlings of cucumber. Peatmoss based substrates, rice hull, carbonized rice hull, decomposed sawdust, perlite and granular rockwool were mixed by five different mixing ratioes (M1, M2, M3, M4 and M5). The cultivars used were cucumber (Cucumis sativus L. cv. Janghyung heukjinju) plants. The higher the content of peatmoss added, the higher the plant growth in terms of plant height, leaf area and total dry weight, which leading to the production of high quality plug seedlings. Seedlings growth of cucumber were greater in M5 mixtures [peatmoss:rice hull:decomposed sawdust=40:40:20(v/v)], M4 mixtures [peatmoss:rice hull:decomposed sawdust:granular rockwool=30:25:20:25(v/v)] and M2 mixtures [peatmoss:rice hull:decomposed sawdust:granular rockwool=20:20:15:25:20(v/v)] The concentrations of nutrient solution (EC) had a great influence on plant height, leaf area, total fresh and dry weight of cucumber seedlings growth. As the concentration of nutrient solution increased from 0.1 to $1.5dS{\cdot}m^{-1}$, the growth and seedling quality of cucumber in plant height, leaf area and dry weight were significantly improved.

• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.197-201
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• 1996

To greatly decrease bolting rate and deterioration of root quality, seeds of Angelica gigas had sown and grown several month earlier than traditional seedtime. Roots were harvested in the middle of November in same year. Roots were devided to several parts such a fune root, secondary root, stele and cortex of main root. We ditermined and compared with the major constisuents contained in each parts of 1 and 2 year old roots. Among each parts of root, the amount of constituents in the fine root and cortex were much higher than those in stele of main root. Content of decursin and decursinol angelate was higher 6.5% in 2 year old root than 4.8% in 1 year old root and their component ratio showed 10:7.5 in 1 year old root and 10:6.0 in 2 year old root, respectively. But merits as a material of oriental medicine for 1 year old root that cultivated by early short-time growing seedling were generally acknowledged.

• Journal of Plant Biotechnology
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• v.47 no.3
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• pp.235-241
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• 2020

This is the first study to establish a complete protocol for micropropagation of Rehmannia glutinosa from root segments. The study involved investigating the effect of plant growth regulators on in vitro shoot regeneration and rooting and identifying substrates supporting survival and growth performance of ex vitro seedlings. A Murashige and Skoog (MS) medium containing 30 g/L sucrose for shoot induction and 0.2 mg/L indole-3-acetic acid (IAA), 1 mg/L 6-benzylaminopurine (BAP), and 1 g/L polyvinylpyrrolidone (PVP) for shoot multiplication resulted in the highest number of shoots per explant and shoot height. Applying a medium containing 0.5 mg/L IAA and 1 g/L PVP yielded optimal rooting of the shoots grown in vitro. Compost enriched with microbial inoculants and perlite enhanced seedling growth better than that with organic biofertilizer-free substrates (soil and sand). We recommend the continuous production of micropropagated R. glutinosa seedlings from root segments under the aforementioned conditions as a possible propagation technique for crops of this species.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.273-279
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• 2012

This experiment was conducted to determine a potential effective biological weed control and/or rice young seedling injury by golden apple snail (Pomacea canaliculata) at wet hill seeded rice field. The rice seeds used were treated by iron-coating. The efficacy of weed control as affected by golden apple snail has been tested with twice applications of young golden apple snails of 12 kg (24,000 young snails, $0.5g{\pm}10%$ per young snail, 30~40 days after hatching) per ha at the same day after harrowing and applied with rate of 10 kg (20,000 young snails) per ha at 15days after seeding, respectively. The comparison of this experiment was of the conventional machine transplanted rice paddy field in terms of weed control and rice plant injury as a visual grade. The weed efficacy was of 100% similar with the conventional paddy field which was applied by systematic herbicides of pre-emergence and post-emergence chemical herbicides and there was 1~3% significant rice young seedling injury but no yield losses and grain quality due to the input of golden apple snail.

• Korean Journal of Medicinal Crop Science
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• v.18 no.2
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• pp.74-78
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• 2010

This experiment was carried out to select suitable organic matter in To-jik nursery (self soil nursery) for complement To-jik nursery's defects that are deterioration of raw material by poor quality of seed ginseng and reduction of the quantity in seed ginseng production. Organic matter used were Yacto, rice bean, defatted rice bran, soybean cake and their mixture. As follows, bulk density in soil physical property by treating organic composts was the greatest in soybean cake and the next was followed by mix, Yacto, defatted rice bran, and rice bran treatment in order. Soil pore space ratio was totally the opposite; that was rice bran the first and followed by defatted rice bran, Yacto, mix and soybean cake treatment. The incidence rate of damping off by treating organic composts was 1.5% in both soybean cake and mix while the others was 1.0%. Emergence time was the same among treatment on April 16 and Emergence rate was the highest at 73% in Yacto. There was no significant differences among treatment in the growth of aboveground part but it was a little better in defatted rice bran treatment. In Yacto treatment, the growth of underground part, total root number per kan, rate of first grade ginseng seedling, and rate of usable ginseng seedling etc. were entirely higher but there was little differences. Using defatted rice bran was slightly lower in productivity compared to Yacto, but the possibility was high as a alternative for Yacto in a view of managing cost down.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.195-195
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• 2022

Abiotic stress is a major problem in global agriculture as it negatively affects crop growth, yield, and quality. Wheat (Triticum aestivum) is the world's second-highest-producing food resource, so the importance of mitigating damage caused by abiotic stress has been emerging. In this study, we performed GWAS to search for SNPs associated with salt tolerance and drought tolerance. NaCl (200 mM) treatment was performed at the seedling stage using 613 wheat varieties in Korean wheat core collection. Root length, root surface area, root average diameter, and root volume were measured. Drought stress was applied at the seedling stage, and the above phenotypes were measured. GW AS was performed for each phenotype data using the MLM, MLMM, and FarmCPU models. The best salt-tolerant wheat varieties were 'MK2402', 'Gyeongnam Geochang-1985-3698', and 'Milyang 13', showing superior root growth. The significant SNP AX-94704125 (BA00756838) were identified in all models. The genes closely located to the significant SNP were searched within ± 250 kb of the corresponding SNP. A total of 11 genes were identified within the region. NB-ARC involved in the defense response, FKSI involved in cell wall biosynthesis, and putative BP Ml involved in abiotic stress responses were discovered in the 11 genes. The best drought-tolerant wheat varieties were 'PI 534284', 'Moro of Sind', and 'CM92354-33M-0Y-0M-6Y-0B-0BGD', showing superior root growth. This study discovered SNPs associated with salt tolerance in Korean wheat core collection through GWAS. GWAS of drought tolerance is now proceeding, and the GWAS results will be represented on a poster. The SNPs identified by GWAS can be useful for studying molecular mechanisms of salt tolerance and drought tolerance in wheat.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.181-192
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• 2023

Appropriate fertilization methods are required according to species to supply necessary nutrients to plants and prevent soil environmental contamination in nurseries. In this study, the effects of nitrogen and phosphorus fertilization on the growth of Liriodendron tulipifera and soil characteristics were investigated. After 16 fertilization treatments (4 levels of nitrogen × 4 levels of phosphorus) were applied to one-year-old L. tulipifera seedlings at the Yongmun Nursery Station of the Korea Forest Service, height, root collar diameter (RCD), biomass, leaf nutrients, and soil characteristics were investigated. The height increased as the amount of nitrogen and phosphorus fertilization increased, and the RCD was the highest in the ×2 treatment. Biomass growth was on average 40.0% higher for the treatment with high nitrogen fertilization compared to the low nitrogen treatment. The seedling quality index was the highest with nitrogen and phosphorus ×2 treatment. Leaf phosphorus and magnesium concentrations decreased when nitrogen fertilization was applied, and leaf potassium concentrations decreased as nitrogen fertilization increased. Soil pH and exchangeable potassium decreased as the amount of phosphorus application increased, and exchangeable magnesium decreased as the amount of nitrogen application increased and increased as the amount of phosphorus application increased. Considering the growth of L. tulipifera seedlings and changes in the soil characteristics at the nursery stage, twice the standard fertilization amount is the appropriate fertilization amount for nursery of the Yongmun Nursery Station. It is expected that this study will contribute to improving nursery soil fertilization management technology for healthy seedling production.