• Research in Plant Disease
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• v.22 no.4
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• pp.264-268
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• 2016

The nursery test against rice blast in Korea from 2014 to 2015 was analyzed. The average of disease severity of leaf blast in 12 sites showed $3.7{\pm}2.1$ in 2014 and $4.4{\pm}2.1$ in 2015. Disease severity of leaf blast in Icheon and Cheolwon was increased ranging from $2.8{\pm}2.2$ in 2014 to $6.3{\pm}1.8$ in 2015. Using a designation system, a total of 588 isolates collected those years were categorized into 34 races in 2014 and 51 races in 2015 based on the reaction pattern of Korean differential varieties. The blast isolates of 2015 were more diverse than those in 2014. The ratios of KI race to KJ race were 54:46 in 2014 and 70:30 in 2015; however, the predominant race population was KJ-301 as 16%, and KI-101 as 15% in 2014 and 2015, respectively. These results indicate that the distribution of the blast races is getting more diverse in Korea, therefore, this research would provide the possibility to predict race distribution and change to prevent the outbreak of rice blast and will also serve as a useful information for breeding of resistant rice cultivar against blast.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.143-150
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• 1983

Red rice (local name "Sore") as a weed has been a serious threat to rice production in direct-seeded rice culture in Ganghwagun, Gyeonggi province. In the Ganghwagun 508 ha out of 1,420 ha in the Samsanmyeon area is infested with red rice. The average lowland rice yield is about 4,300 kg/ha in the Ganghwagun, but the average upland rice yield is about 2,000 kg/ha in infested area. This study was carried out in order to clarify the ecological characteristics of red rice and factors affecting the competitive ability of five red rice varieties, collected from Samsanmyeon in 1981, with rice cultivar. Five varieties-Monggeunsare, Salsare, Ginkaragsare, Galsaegsalsare, Galsaegkaragsare-showed the same morphological characteristics of cultivated Japonica type, Chuncheongbyeo, but red rice tillers more profusely, is taller and lodges more easily than Chucheongbyeo. It shatters easily about 10-15 days after heading date, and at this time the hull is discolored in yellow or dark brown. There are many types of red rice with short or long owns on the spikelet, occasionally with or without own on the spikelet in the same hill, and the grains are short or long. In red reice leaf blast occurs more severely than in cultivated Indica/Japonica type, Teabaegbyeo, particulary serious in Monggeunsare. When red rice invaded in direct-seeded rice, number of panicles of rice became reduced more than other yield components.

• Korean journal of applied entomology
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• v.14 no.3 s.24
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• pp.111-131
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• 1975

The study has been carried out to investigate the occurrence, damage, characteristics of the pathogen, environmental conditions affecting the disease outbreak, varietal resistance, forecasting, and chemical control of bacterial leaf blight of rice in Korea since 1964. Bacterial leaf blight of rice became a major disease in Korea since 1960. A correlation was found between the annual increase of epidemics and increase of cultivation area of susceptible varieties, Jinheung, Keumnampung etc. Areal damage within the country showed that the more was at southern province, Jeonnam, Gyeongnam and western coast, and at flooded rice paddy. Yield reduction directly related with the amount of infection on upper leaves at heading stage. Fifty per cent of reduction resulted when the lesion area was more than 60 per cent. Less than 20 per cent of lesion area, however, was not affected so much on yield loss One hundred and six isolates collected from all over the country were classified as 8 strains by using 4 different bacteriophages in 1973. It was, however, only two in 1965. There were some specificities on varietal distributions among the strains such as that the Jinheung attacked mainly by strain A, B, C and I, those attack Kimmaze were A, B, H and I. Most strains were found from Tongil except D and E, whereas Akibare was only variety that attacked by strain E. Low temperature, high humidity, heavy rainfall and insutficient daylight favored the disease epidemics. Especially, typhoon and flooding at heading stage were critical factors. The earlier transplanting the more disease was resulted, and more nitrogen fertilizer application accerelated the diseased development in general. The resistance to the disease varied by growing stage of the sane plants. All of recommended varieties in Korea were susceptible to the disease except Norm No. 6 and Sirogane which moderately resistant. The pathogen, Xanthomonas oryzae, was detectable from extract of healthy seedlings that were grown in the field with an heavy infection previous year. The more bacteriophage in irigation water resulted the more disease outbreak, and the existence of more than 50 bacteriophages in 1ml. of irrigation water were necessary to initiate the disease out break. The curves representing occurrence of bacteriophages and disease outbreak were similar with 15 days interval. The survey of bacteriophage occurrence can be utilized in forecasting of the disease two weeks ahead of disease outbreak. Three applications of chemicals, Phenazin and Sangkel, in weekly intervals at the early satage of out-break depressed the symptom development, and increased yield by 20per cent. Proper period for the chemical application was just before the number of bacteriophage reaches 50 in 1ml. of irrigation water.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.239-249
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• 2020

Rice flour varieties have been developed to replace wheat, and consumption of rice flour has been encouraged. damage related to pre-harvest sprouting was occurring due to a weather disaster during the ripening period. Thus, it is necessary to develop pre-harvest sprouting rate prediction system to minimize damage for pre-harvest sprouting. Rice cultivation experiments from 20 17 to 20 19 were conducted with three rice flour varieties at six regions in Gangwon-do, Chungcheongbuk-do, and Gyeongsangbuk-do. Survey components were the heading date and pre-harvest sprouting at the harvest date. The weather data were collected daily mean temperature, relative humidity, and rainfall using Automated Synoptic Observing System (ASOS) with the same region name. Gradient Boosting Machine (GBM) which is a machine learning model, was used to predict the pre-harvest sprouting rate, and the training input variables were mean temperature, relative humidity, and total rainfall. Also, the experiment for the period from days after the heading date (DAH) to the subsequent period (DA2H) was conducted to establish the period related to pre-harvest sprouting. The data were divided into training-set and vali-set for calibration of period related to pre-harvest sprouting, and test-set for validation. The result for training-set and vali-set showed the highest score for a period of 22 DAH and 24 DA2H. The result for test-set tended to overpredict pre-harvest sprouting rate on a section smaller than 3.0 %. However, the result showed a high prediction performance (R2=0.76). Therefore, it is expected that the pre-harvest sprouting rate could be able to easily predict with weather components for a specific period using machine learning.

• Journal of Mushroom
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• v.20 no.3
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• pp.113-118
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• 2022

This study was conducted to diversify the cultivation of mushroom items and develop a competitive variety of Hypsizigus marmoreus. We focused on developing Hypsizigus marmoreus with lower bitterness, likable shape, and high yield. We have collected and tested characteristics of genetic resources from domestic and abroad since 2019. Breeding (2019), characterization (2020), productivity test (2021), and farm demonstration test (2021) have been sequentially conducted. We bred the new variety 'Yunseul' with unique traits. The optimal temperature for mycelial and fruit body growth were 22-25℃ and 15-18℃, respectively. It was similar to the control variety (Mangadak-2Ho) in the pileus form (hemispherical shape) and the cultivation period. However, it was thinner and longer than the control variety with the pileus diameter, thickness, stipe diameter, and length being 19.9 mm, 7.0 mm, 9.4 mm, and 86.3 mm, respectively. The effective number of fruit bodies was 47.8 in bottle cultivation, which was more than that of the control variety. The yield was 197.4 g/bottle (1,100 cc), which was 30% higher than the yield of the control variety, 151.9 g/bottle (1,100 cc). The parent and control varieties were also incubated alongside the new variety. The somatic incompatibility line was distinct. The band pattern in the mycelial DNA PCR reaction was different from that of the parent and control varieties, confirming the hybrid species.

• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.46-50
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• 2002

In DNA level, genetic study of Angelica species was firstly conducted to discriminate the bolting-resistant or low bolting variety, so called as Manchu, from other Korea collected lines and also this technuque was applied to identify the origin of commercial dried materials obtained from current oriental medicinal market. By RAPD analysis with 72 primers including sixty of 10-mers and twelve of 20-mers, respectively, three primers, which were related to the bolting resistant traits of Angelica gigas, were identified. Comparing the RAPD bands, URP04 primer showed the 1.7 kb specific band, which seemed to be related to delaying bolting traits, since it was observed only in Jinbu elite lines but not in others. On the other hand, since 1.2 kb band amplified by OPD11 was observed in other collected lines but not in Manchu var. and Jinbu line, this primer also could be considered as a selection marker for identifying bolting resistant or delaying bolting traits. In the same manner, since OPP09 did not show 1 kb major band but produced 0.8 kb and 1.2 kb bands in Manchu var., these three bands amplified by the primer could be considered one of the important key specifying Manchu var. related with the trait of Angelica gigas. OPC02 primer showed the same band patterns in all Korean collected lines, but not in other foreign introduced lines, such as A. sinensis from China, and A. acutiloba from Japan. Since these four RAPD primers, OPD11, OPP09, URP04, and OPC02 showed the specific polymorphisms in Angelica species, thus, these were useful to discriminate the three Angelica species, A. gigas, A. sinensis, and A. acutiloba.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.297-312
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• 2012

This study was carried out to investigate the flora of Mt. Seoungma (Gyeonggi-do). The vascular plant were collected 13 times (from March to October 2011), and 384 taxa in total were identified, including 94 families, 260 genera, 340 species, 5 subspecies, 37 varieties and 2 forms. Korean endemic plants of this area were nine taxa; Clematis brachyura, Rhododendron mucronulatum, Forsythia koreana, Paulownia coreana, etc. Rare plants (IUCN) by the Korean Forest Service and Korean National Arboretum three taxa were recorded; one Critically Endangered species (CR), Prunus yedoensis, one Vulnerable species (VU), Epimedium koreanum, one Least Concemed species (LC), Phacelurus latifolius. The floristic regional indicator plants found in this area were 15 taxa comprising two taxa of grade V and III, one taxa of grade II, 10 taxa of grade I. Furthermore, therophytes (28.3%), hemicryptophytes (23.0%), hydrophytes (14.3%) showed high proportional ratio in life form spectrum. The naturalized plants were identified as 43 taxa and the percent of naturalized index (NI) was 11.2% of total 384 taxa vascular plants. The vegetation status of investigated area was comparatively well conserved, but the degree of damage was increasing rapidly by the disturbances of human beings. Therefore, a long-term monitoring of vegetation changes and movement grasp must become accomplished.

• Korean Journal of Environment and Ecology
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• v.27 no.3
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• pp.280-304
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• 2013

This study was carried out to investigate the flora of Mt. Gilsangsan (Ganghwa-Isl.). The vascular plants were collected 14 times (from March to November 2012), and were identified as 595 taxa; 122 families, 359 genera, 529 species, 7 subspecies, 51 varieties, 2 forms and 3 hybrids. The plant formation of Mt. Gisangsan is the deciduous broad-leaved and conifer mixed forest which is the common one in the middle part of Korean peninsula. All most mountain covered with young secondary forest which is mainly composed of Pinus and Quercus. The family represented by the largest number of species diversity were Asteraceae (11.%), Poaceae (10.7%), Cyperaceae (6.38%), Fabaceae (3.86%) and Rosaceae (3.52%) respectively. Korean endemic plants of this area were 12 taxa; Asarum misandrum, Clematis brachyura, Philadelphus schrenkii, Forsythia koreana, Polygonatum infundiflorum, etc. The red list of vascular plants according to IUCN valuation basis were examined, endangered species (EN) Abies koreana, Near Threatened species (NT) both Wikstroemia trichotoma and Sparganium erectum, Least Concern species (LC) Platycladus orientalis, Swertia diluta var. tosaensis and Iris minutoaurea and by Not Evaluate species (NE) Polygonatum infundiflorum. The floristic regional indicator plants found in this area were 45 taxa comprising two taxa of grade V and VI, nine taxa of grade III, three taxa of grade II, 29 taxa of gradeI. The naturalized plants were identified as 64 taxa and the percent of naturalized index (NI) was 10.7% of total 595 taxa vascular plants. Ecosystem disturbance wild plants were consisted of eight taxa; Rumex acetosella, Sicyos angulatus, Solanum carolinense, Ambrosia artemisiifolia, Ambrosia trifida, Aster pilosus, Hypochaeris radicata and Lactuca scariola. Furthermore, therophytes (26.5%), hemicryptophytes (26.0%), Geophyte (14.0%) showed high proportional ratio in life form spectrum.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.321-330
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• 1987

In the endemic area of bovine piroplasmosis in Chonbuk Province, total of 486 heads of Holstein cow selected from 14 farms randomly were examined the infection status of piroplasma and their blood values. The results obtained were summarized as follows: 1. The etiological agent was only Theileria sergenti and none of the Babesia sp. infection. 2. All of the 486 heads of examined cow were infected with Theileria sergenti (100%). 3. In the initial examination of 11 farms in early summer, the means of blood values were as follows; RBC:$526{\pm}84(10^4/mm^3$), Ht:$27.9{\pm}2.8%$, SP:$7.5{\pm}0.6g/dl$, WBC: $11586{\pm}354/mm^3$, and Fibrinogen: $578.5{\pm}164.1mg/dl$. 4. In the second examinations in slimmer season, the blood values of examined cows had little varieties. But in the winter season, cows housed in the barn, the blood values were greatly increased; RBC: $601{\pm}77(10^4/mm^3)$, (F-value: 37.186**), Ht: $30.5{\pm}1.3%$(F-value: 15.626**) Hb: $12.2{\pm}1.3g/dl$(F-value: 5.899**), SP: $7.4{\pm}0.6g/dl$(F-value: 5.05**). 5. To determine the piroplasma infection in the many herds of cow, the measurement of Ht, Hb, and SP values etc. were more effective and helpful to find the weak cow because the examined process are not only to be easily carry out many samples but also to be done very simple and rapidly. 6. The indications of therapeutic standard values were stablished as follows; the less than 20% in the Ht value, below the 10g/dl in the Hb value, and less than 6g/dl in SP value. When the one among the therapeutic standard values, Ht, Hb, and SP was below the therapeutic standard value, the cow was treated with nutriments. When more than two among them were below the therapeutic standard, the cow was treated with Berenil, at once. In this way, there was no one head which represented clinical signs of piroplasmosis among 486 heads of cow at 14 farms during the year of 1986. 7. In a Korean native cattle infected with Thieleria sergenti seriously, the recovery of blood values was very prolonged by the treatment of Berenil only. But by the transfusion of 300ml blood collected from normal cow, the blood values were recovered rapidly.

• Korean Journal of Environment and Ecology
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• v.24 no.4
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• pp.363-394
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• 2010

This study was carried out to investigate the vascular flora of the Hongcheon-gun area in Gangwon Province. The vascular plants were collected 13 times(from April 2008 to May 2009), and 1,055 taxa in total were identified, including 43 orders, 118 families, 443 genera, 903 species, 6 subspecies, 125 varieties, 18 form and 3 hybrids. Among them, 37 taxa of Korean endemic plants and the Office of Forestry-designated rare & endangered plants were identified as 35 taxa. Based on the list of plants which have been approved for overseas delivery, 61 taxa were recorded in the investigated area. The Ministry of Environment-designated plants, which should be protected by the wildlife protection law, were identified as four taxa and 224 taxa of specially designated plants by the Ministry of Environment. The naturalized plants were identified as 45 taxa, and their naturalization ratio and urban index were found to be 4.3%, and 16.1% respectively. 1,055 taxa listed consists of 359 taxa(34%) of edible plants, 293 taxa(27.7%) of medicinal plants, 166 taxa(15.7%) of pasture plants, 143 taxa(13.5%) of ornamental plants, 41 taxa(3.9%) of timber plants, 25 taxa(2.3%) of fiber plants and 3 taxa(0.2%) of industrial plants.