• Title/Summary/Keyword: plant disease

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Epidemiology and Control of Rice Blast in Korea (한국(韓國)에서의 도열병(病) 발생(發生), 만연(蔓延)과 그 방제(防除))

  • Park, Jong Seong
    • Korean Journal of Agricultural Science
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    • v.12 no.2
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    • pp.356-369
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    • 1985
  • In Korea, inevitable researches for the blast control exactly started from 1927 by the organization of Office of Rural Development with the local extensive outbreak of panicle blast at Jeonlla Buk-Do Province in 1926. At present, the rice blast is still one of the most destructive and widespread diseases in spite of considerable contributions by rice scientists, particularly plant pathologists during last 55 years in Korea. Rice blast control and management are very difficult because of the marked variability in pathogenicity of the blast fungus. From the results obtained through the disease surveys during last 70 years, different 3 prevalence type of blast such as bimodal leaf-blast type, bimodal panicle-blast type and bimodal continual blast type were recognized. In generally speaking, pattern of blast outbreak is said to be characterized by severe outbreak of panicle blast after slight outbreak of leaf blast with discontinuity between leaf and panicle blast. So we have to pay much attention for successful management of panicle blast giving direct influence to rice yield. Main factors induce blast epidemic were pointed out to be breakdown of the disease resistance, nutritional unbalance such as excess application of nitrogen, delay of transplantation and longspell of rain fall by extensive surveys and researches on blast during last 70 years in Korea. The fact some of Japonica varieties such as Kokuryomiyako, Tamanishiki, Ginbozu and Pungok belong to varietal group A had been cultivated with extensive acrage over 30 years in this country should be mentioned by Korean rice scientists. Differences in field resistance between varieties in the same group are detectable and apparently small but sometimes epidemiologically significant differential effects may be found out in case of blast. Much more attention should be payed to accumulate the knowledges on field resistance for successful management of blast. Excess application of nitrogen is more effective to outbreak of panicle blast than that of leaf blast of IR varieties. In comparatively low level application of nitrogen infection rate of panicle blast of IR varieties is considerably high. Low temperature effects on outbreak of blast is very great. It results in remarkable increase of the inoculum potential on the leaf lesions and infection of panicle blast in leaf sheathes of IR varieties during the booting stage. In economic point of view, it is concluded that 5 times sprays of effective fungicides including 3 times before and 2 times after heading is good enough to control blast. We have experienced no one of control measures for blast is superior to all others. The integrated control measures was established as guideline of blast control around 1950 in Korea. This guideline must be helpful for rice growers as long as rice growing continue.

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Nature of Suppressiveness and Conduciveness of Some plant pathogens in Soils (토양내(土壤內) 식물(植物) 병원균(病原菌)의 발병억제(發病抑制) 및 유발성질(誘發性質))

  • Shim, Jae-Ouk;Lee, Min-Woong
    • The Korean Journal of Mycology
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    • v.18 no.3
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    • pp.164-177
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    • 1990
  • This study was carried out to obtain some useful data for increasing an effective ginseng production. There was a direct relationship (r=0.2645) between spore germination of Fusarium solani and soil pH, and (r=0.315) between Cylindrocarpon destructans and soil pH. On the other hand, there was a direct relationship (r=0.19) between relative hyphal growth of Rhizoctonia solani and soil pH. There was a direct relationship (r=0.21) between number of total bacteria and F. solani, (r=0.37) between actinomycetes and F. solani and (r=0.20) between celluloytic bacteria and F. solani. However, there was an inverse relationship (r=-0.20) between number of total fungi and F. solani. There was a direct relationship (r=0.24) between number of actinomycetes and R. solani. Each ginseng pathogen-suppressive soil screened was 40 in F. solani, 20 in C. destructans and 9 soil samples in R. solani among 146 soil samples, respectively. The mean contents of K, Ca and Mg were fairly lower in each ginseng pathogen-suppressive soil than conducive soil, whereas Na were somewhat lower. The mean contents of organic matter were over 2 times higher in each ginseng pathogen-suppressive soil than conducive soil. The mean contents of phosphate were fairly lower in F. solani and R. solani-suppressive soil than conducive soil and, on the other hand, were somewhat higher in C. destructans-suppressive soil than conducive soil. The mean soil pH was somewhat lower in each ginseng pathogen-suppressive soil than conducive soil. The mean contents of sand were about 2 times higher in each ginseng pathogen­suppressive soil than conducive soil, whereas silt and clay were somewhat lower. The microbial numbers of total bacteria, total fungi and celluloytic fungi were higher in F. solani-suppressive soil than conducive soil, whereas actinomycetes and celluloytic bacteria were lower. Each microbial number of total bacteria or total fungi indicated a significant difference (p=0.05) between F. solani­suppressive and conducive soil, and the microbial number of actinomycetes was a highly significant difference (p=0.01) between F. solani-suppressive and conducive soil. The microbial numbers of total bacteria, total fungi, actinomycetes and celluloytic fungi were higher in C. destructans-suppressive soil than conducive soil, whereas celluloytic bacteria were about 2 times lower. On the other hand, the microbial numbers of total fungi were higher in R. solani-suppressive soil than conducive soil, whereas total bacteria, actinomycetes, celluloytic bacteria and celluloytic fungi were lower. Fourteen of 16 F. solani-suppressive soils tested were suppressive to ginseng root rot, whereas fifteen of 16 C. destructans-suppressive soils were suppressive. Ginseng root rots of ginseng disease-suppressive soils were in the range of 1.0-17.4% in F. solani-suppressive soil and 0.2-20.4% in C. destructans-suppressive soil, respectively.

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Validity Test for Molecular Markers Associated with Resistance to Phytophthora Root Rot in Chili Pepper (Capsicum annuum L.) (고추의 역병 저항성과 연관된 분자표지의 효용성 검정)

  • Lee, Won-Phil;Lee, Jun-Dae;Han, Jung-Heon;Kang, Byoung-Cheorl;Yoon, Jae-Bok
    • Horticultural Science & Technology
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    • v.30 no.1
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    • pp.64-72
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    • 2012
  • Phytophthora root rot has been causing a serious yield loss in pepper production. Since 2004, the year in which commercial cultivars resistant to the disease were firstly commercialized, it has been necessary to introduce the resistance into domestic pepper cultivars for dried red pepper. Therefore, developing molecular markers linked to the resistance is required for an accurate selection of resistant plants and increasing breeding efficiency. Until now, several markers associated with the major dominant gene resistant to Phytophthora root rot have been reported but they have some serious limitations for their usage. In this study, we aimed to develop molecular markers linked to the major dominant gene that can be used for almost of all genetic resources resistant to Phytophthora root rot. Two segregating $F_2$ populations derived from a 'Subicho' ${\times}$ 'CM334' combination and a commercial cultivar 'Dokyacheongcheong' were used to develop molecular markers associated with the resistance. After screening 1,024 AFLP primer combinations with bulked segregant analysis, three AFLP (AFLP1, AFLP2, and AFLP3) markers were identified and converted into three CAPS markers (M1-CAPS, M2-CAPS, and M3-CAPS), respectively. Among them, M3-CAPS marker was further studied in ten resistants, fourteen susceptibles, five hybrids and 53 commercial cultivars. As a result, M3-CAPS marker was more fitted to identify Phytophthora resistance than previously reported P5-SNAP and Phyto5.2-SCAR markers. The result indicated that the M3-CAPS marker will be useful for resistance breeding to Phytophthora root rot in chili pepper.

Evaluation of Electrocardiographic Index in Healthy Raccoon Dogs (Nyctereutes procyonoides) (건강한 너구리(Nyctereutes procyonoides)들의 심전계 지표에 대한 평가)

  • Hong, Won-Woo;Kim, Jong-Taek;Yang, Dong-Keun;Nam, Hyo-Seung;Hyun, Changbaig
    • Journal of Veterinary Clinics
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    • v.30 no.6
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    • pp.456-458
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    • 2013
  • The aim of this study is to evaluate the reference value for electrocardiogram in healthy captive raccoon dogs. Forty-one free-ranging adult raccoon dogs rescued from Wildlife rescue centre, Kangwon National University were enrolled in this study. The 6-lead electrocardiogram was obtained in all raccoon dogs without any chemical restraints. The mean heart rate was $146.10{\pm}43.31$ beats/min (95% confidence interval 132.84~159.36 beats/min). The mean respiration rate was $35.73{\pm}11.56$ breaths/min (95% confidence interval 32.19~39.27 breaths/min). The mean systolic blood pressure was $136{\pm}29.26$ mmHg (95% confidence interval 127.99~145.91 mmHg). Electrocardiographical features were also evaluated in all raccoon dogs. The mean duration and amplitude of P-wave were $38.2{\pm}4.0$ ms (range 28-40 ms) and $0.128{\pm}0.039$ mV (range 0.09~0.20). The mean duration and amplitude of QRS complexes were $48.5{\pm}7.2ms$ (range 36-60 ms) and $1.330{\pm}0.650$ mV (range 0.15~2.30). The range of the mean electrical (QRS) axis was $-91^{\circ}{\sim}+96^{\circ}$ ($10^{\circ}{\sim}60^{\circ}$; 95% of confidence interval). The mean corrected QT (QTc) interval was $273.7{\pm}32.7ms$ (range 212-333 ms), while the mean PR interval was $76.1{\pm}10.0ms$ (range 50-82 ms). To the authors' knowledge, this is the first study to provide references in electrocardiogram (ECG) in healthy captive raccoon dogs.

Studies on the Seasonal Increase of the Population of the Smallerbrown Planthopper, Laodelphax striatellus(Fallen) (애멸구의 세대별 증식동태에 관한 연구 -기주식물의 종류와 생육단계와 증식과의 관계-)

  • Hyun Jai Sun;Woo Kun Suk;Ryoo Mun Il
    • Korean journal of applied entomology
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    • v.16 no.1 s.30
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    • pp.13-19
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    • 1977
  • The smaller brown planthopper overwinters mostly as the fourth instar nymph. The emerged adult disperses to winter barley or wheat plants. The adult of the first generation disperses into the rice field, and spends three generations in the rice field. The population densities of the adults of the first generation and the overall density of the second generations are the most important in relation to the incidents of the rice stripe disease which is transmitted by this insects. This study was intended to analyse the population increases in these important generations in relation to the kind and the different growing stage of the host plants. The insects were reared on potted host plants of different growing stage in the insect cages. The population increases of the insects in the cages were compared with those on the rice seedlings in the laboratory. The results are as follows: 1. The average longevities of the adults of the generations were 13.4 days for the overwintered, 12.9 days for the first, and 10.2 days for the second generation, and showed no significant differences between the generations even they seemed to be shorter than normal condition probably caused by the frequent disturbance at the time of food renewal in 2 or 3 days. 2. When they were reared on the rice seedling, the average numbers of the eggs per female were 131.2 for the overwintered generation, 124.9 for the first generation grown on the barley, and 142.3 for the second generation grown on rice, and shelved no significant differences between the generations. More than $90\%$ of the eggs were laid within 3 weeks. 3. The hatchabilities of the eggs laid on the rice seedling in laboratory were $77.4\%$ for the first generation, $93.1\%$ for the second generation and $62.1\%$ for the third generation. The estimated hatchabilities of the eggs were $67.5\%$ for the first generation, $84.1\%$for the second generation, and $21.9\%$ for the third generation with the growing plants on the plots. The hatchability on the eggs laid by the adults infested on the barley on May 17 was $13.5\%$ compared with $67.5\%$ for the eggs laid by those infested on barley in late April. 4. The average total nymphal periods were 19.4 days for the first generation, and 13.3 days for the second generation in the laboratory and the mortalities of the nymphs seemed to related with the growing stages of the host plants. 5. With the pot experiments, the average per cents of the emerged adults were $37.2\%$ for the first generation, $55.3\%$ for the second generation, and $11.6\%$, for the third generation. The average numbers of the emerged adults were $7.4\%$ for the pots infested on the barley on May 17, instead of $37.2\%$ adults for those infested in late April. 6. From above results, it may suggest that the innate qualities of the insect are not significantly different between generations, and the differences in the increase of the population for the generations might effected considerably by the differences in the physiological conditions of tile host plant, besides the differences in physical and other biological factors.

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Growth Characteristics and Forage Productivity of New Forage Barley Variety, 'Miho' (청보리 신품종 '미호'의 생육특성과 수량성)

  • Oh, Young-Jin;Park, Tae-Il;Park, Hyoung-Ho;Han, Ouk-Kyu;Song, Tae-Hwa;Park, Jong-Chul;Kim, Yang-Kil;Park, Jong-Ho;Kang, Hyeon-Jung;Kang, Chon-Sik;Cheong, Young-Keun;Kim, Kyong-Ho;Kim, Bo-Kyeong;Yun, Geon-Sig;Hong, Gi-Heung;Bae, Jeong-Suk;Lee, Seong-Tae
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.36 no.4
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    • pp.370-375
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    • 2016
  • The purpose of development new variety 'Miho' (Hordeum vulgare L.) is a favorite with livestock feed and develop varieties resistant to disease and lodging. 'Miho' was carrying out the growth habit of group III with green and mid-wide leaf. Awn that is related to preference of livestock is a semi-smooth awn. This cultivar had 96 cm of culm length, 650 of spikes $per\;m^2$. Heading date of 'Miho' was April 27, and maturing date on May 30, which were later than cultivar 'Youngyang'. It also showed strong winter hardiness, and similar resistance to shattering and bariy yellow mosaic virus (BaYMV) compared with those of check one. The best thing among the traits of a good quality with the plant green at the latter growing period. The average forage dry matter yield in the regional yield trial was about 13.1, 12.1 MT per ha in upland and paddy field, respectively, which were 9%, 2% higher than that of the check cultivar. It's also showed 6.8% crude protein, 27.1% ADF (acid detergent fiber), and 67.5% TDN (total digestible nutrients), including higher silage quality for whole crop barley. This cultivar would be suitable for the area whose average minimum temperature was above $-8^{\circ}C$ January in Korean peninsula.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

Allium hookeri Extract Improves Type 2 Diabetes Mellitus in C57BL/KSJ Db/db Obese Mouse via Regulation of Hepatic Lipogenesis and Glucose Metabolism (삼채 추출물의 인슐린 저항성 개선 효과 및 기전 탐색)

  • Kim, Ji-Soo;Heo, Jin-Sun;Choi, Jong-Won;Kim, Gun-Do;Sohn, Kie-Ho
    • Journal of Life Science
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    • v.25 no.10
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    • pp.1081-1090
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    • 2015
  • Diabetes has been one of major health risks in industrialized countries. Allium hookeri is a wild herb distributed in India and Myanmar. The root of the plant has been used as food and medicine in Southeast Asia. We investigated Allium hookeri extract improves type 2 diabetes mellitus in C57BL/KSJ db/db obese mouse. C57BL/KSJ db/db obese mouse arise out of Type 2 diabetes and we treated Allium hookeri methanol extract 400 mg/kg (AH 400), 800 mg/kg (AH 800), positive control group (thiazolidinedine;TZDs) were administered orally for 8weeks. AH treated group normalized lipid enzyme system (triglyceride, total cholesterol, HDL-cholesterol and LDL-cholesterol) and serum glucose, HbA1c and plasma insulin level. AH treated group recovered β-cell damage by hyperglycemia and fatty liver disease. AH treated group significantly up regulated expression of Peroxisome proliferator-activated receptor gamma (PPAR-γ), pyruvate dehydrogenase kinase4 (PDK4), Sterol regulatory element-binding protein 1c (SREBP 1) and fork head box O1 (FOX 01) proteins in C57BL/KSJ db/db obese mouse liver. And we found that AH treated group decreased hepatic malondialdehyde formation in C57BL/KSJ db/db obese mouse liver. These results indicate that Allium hookeri methanol extract might be a potential anti-diabetic agent and could be useful in the treatment of type 2 diabetes mellitus.

Gain Threshold Estimation for Some Pests in Major Crops (주요 작물 몇 가지 병해충에 대한 수익역치 추정)

  • Park, Hong-Hyun;Yeh, Wan-Hae;Park, Hyung-Man
    • Korean journal of applied entomology
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    • v.46 no.1 s.145
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    • pp.63-69
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    • 2007
  • This study was conducted to examine the problems that would arise in our cropping systems when introducing Gain Threshold (GT) which is an important element in determining Economic Injury Level (EIL). Cain Threshold (GT) can be defined as the amount of damage (=yield loss) to justify management, and calculated by dividing the management costs by the market crop price. GTs for some pests in rice, soybean, and greenhouse vegetable crops cultivation were estimated and also compared with those in foreign countries. GTs and percentage of yield loss equivalent to them were estimated to be 4.6-6.1kg/10a/season and 1.0-1.3% for brown planthopper, white-backed planthopper, rice water weevil, and sheath blight, whereas for rice blast in rice cultivation were 12.7kg/10a/season and 2.7%. In soybean cultivation, the values for bean bug were 6.2 kg/10a/season and 3.6%. GTs and percentage of yield loss estimated for melon thrips, whitefly, and downy mildew in cucumber cultivation were 10.0-12.6kg/10a/week, 1.4-1.7%, and the values for two spotted mite and gray mildew in strawberry cultivation were 3.1-3.5kg/10a/week, 1.3-1.5%, and the values for American leaf minor, whitefly, and gray mold in tomato were 8.4-9.7kg/10a/week, 1.7-1.9%. Overall GTs in our cropping systems were so low compared to those in foreign countries, which meant that the low GTs might yield the low EILs. Therefore, we could suggest that prior to direct introduction of GTs calculated from current cultivation systems in developing EILs it is necessary to seriously consider reasonable values of GTs or the yield loss equivalents to them.

Major character analysis of CAX 1 (cation exchanger 1) transgenic rice plants in In Vivo (CAX 1 형질전환체 벼의 In Vivo에서 주요특성 분석)

  • Kim, Kyung-Min
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.54 no.4
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    • pp.375-383
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    • 2009
  • This study was carried out to develop transgenic rice cultivars with the CAX1 (accession no. U57411) gene. We successfully selected the transgenic rice plants over-expressing the Arabidopsis H+/$Ca^{2+}$ antiporter CAX1 (accession no. U57411) gene in T6 generation. The brown rice of the CAX1 expressing rice contained 13.4~68.0 % more calcium $(Ca^{2+})$ than that of the wild type and 5 lines were selected based on the phenotypes compared to the control cultivar at the GMO field. The CAX1 expressing transgenic rice plants were similar in phenotype to the wild type during the whole growth period. Also these selected 4 lines appeared to be resistant to blast, cold and water solution compared with the wild type. Difference in 1,000 grain weight of brown rice was observed among each line but grain shape did not show any morphological alternations. These results suggest the enhanced Ca-substrate specificity of CAX1 exchanger in donor plant. Therefore, intact CAX1 exchanger can be functionally useful for $Ca^{2+}$ nutrient enrichment of rice with reduced accumulation of undesirable cation.