Ginseng (Pnanx ginseng C. A. Meyer) is famous worldwide, and is very important cash crop and medicinal herb in Korea. It takes four to five years to produce harvestable ginseng roots, and ginseng is attacked by several pathogens during cultivation. We investigated the disease rate caused by ginseng root rot from 6 years old ginseng cultivation fields (Chungnam; 9 fields, Chungbuk; 11 fields, Gangwon 5 fields). The highest disease severity was Dangjin D (2.9) and the lowest one was Gaesan C (0.6). Of the 625 isolations, 340 isolations were classified as Ilyonectria radicicola and Fusarium solani. Finally, genetic diversity of I. radicicola and F. solani was confirmed by sequence analysis. Among the I. radicicola group, I. mors-panacis, which is known as highly virulent pathogen, and I. liriodendri, I. robusta and I. cyclamicicola, which are weakly virulent pathogens, were identified. In the case of F. solani, it is divided into two groups, but it is necessary to conduct diversity research through genetic analysis and pathogenetic studies using various markers. Based on these results, it could be used as a basic data for control of ginseng root rot pathogens.

Background: Some phenolics detected in the soil may inhibit the seed germination and seedling growth of ginseng (Panax ginseng). This study investigated the effect of irrigation and ginseng root residue addition on the soil microbial community and root rot disease in 2-year-old ginseng. Methods and Results: Each 20 ℓ pot was filled with soil infected with ginseng root rot pathogens, and irrigated daily with 2 ℓ of water for one month. After the irrigation treatment, ginseng fine root powder was mixed with the irrigated soil at a rate of 20 g per pot. In descending order, NO3 −, electric conductivity (EC), exchangeable Na (Ex. Na) and K (Ex. K) decreased due to irrigation. In descending order, NO3 −, EC, Ex. K, and available P2O5 increased with the additon of ginseng powder to the soil. The abundance of Trichoderma crassum decreased with irrigation, but increased again with the incorporation of ginseng powder. The abundance of Haematonectria haematococca increased with irrigation, but decreased with the incorporation of ginseng powder. The abundance of Cylindrocarpon spp. and Fusarium spp., which cause ginseng root rot, increased with the incorporation of ginseng powder. The abundance of Arthrobacter oryzae and Streptomyces lavendulae increased with irrigation. The abundance of Streptomyces lavendulae decreased, and that of Arthrobacter spp. increased, with the incorporation of ginseng powder. Aerial growth of ginseng was promoted by irrigation, and ginseng root rot increased with the incorporation of ginseng powder. Conclusions: Ginseng root residues in the soil affected soil nutrients and microorganisms, and promoted ginseng root rot, but did not affect the aerial growth of ginseng.

Background : This study was conducted to investigate the resistance of Collectotrichum gloeosporioides to 9 fungicides. Methods and Results : With 3 isolates of Collectotrichum gloeosporioides obtained from diseased leaf of ginseng, it was conducted to detect the fungicide resistance of C. gloeosporioides against 9 chemicals through an agar dilution method. PDA medium was used for monitoring the resistance. Among the chemicals, fenhexamid・prochloraz manganese complex, fluazinam and metconazole exhibited high antifungal activity to the ginseng anthracnose fungus. When measuring the effectiveness for the prevention of anthracnose, 3 fungicides at 10 ㎍/㎖ showed 88.1 - 94.7% of preventive effect against C. gloeosporioides. But, the isolates resist to dimethomorph・dithianon, iminoctadine tris (albesilate), kasugamyci n・thiophanate-methyl, dimethomorph・pyraclostrobin, azoxystrobin. Conclusion : In summary, to develop the control system with fungicides, 3 fungicides (fenhexamid・prochloraz manganese complex, fluazinam and metconazole) were applied on ginseng at the indicated time. A reduced spray program based on efficacious fungicides will be useful for ginseng growers and provide more options for controlling anthracnose in Korea.

Background : Root rot is a major factors of replanting failure in ginseng cultivation. Some of the phenolics detected in the soil could inhibit the seed germination and seedling growth of ginseng. Methods and Results : Water of 2 ℓ was irrigated per pot (20 ℓ) into the soil infected with ginseng root rot pathogens for one month every day. After the irrigation treatment, the powder of ginseng fine root of 20 g per pot was mixed with the irrigated soil. NO3 -, electric conductivity (EC), exchangeable Na (Ex. Na) and K (Ex. K) were decreased in descending order by irrigation. NO3 -, EC, Ex. K, and available P2O5 were increased in descending order by incorporation of ginseng powder into soil. Trichoderma crassum was decreased by irrigation, but it was increased again by incorporation of powder. Haematonectria haematococca was increased by irrigation, but it was decreased by incorporation of powder. Cylindrocarpon spp. and Fusarium spp. causing ginseng root rot were increased by incorporation of powder. Arthrobacter oryzae and Streptomyces lavendulae were increased by irrigation. Streptomyces lavendulae was decreased, and Arthrobacter spp. was increased by incorporation of powder. Aerial growth of ginseng was promoted by irrigation, and ginseng root rot was increased by incorporation of powder. Conclusion : The residues of ginseng root in the soil affected soil nutrients and microorganisms, and promoted ginseng root rot, but did not affect the aerial growth of ginseng.

Background: A soil-borne pathogenic fungus, Ilyonectria radicicola (Cylindrocarpon destructans) causes root rot on ginseng (Panax ginseng C. A. Meyer) and is known to attack many other plants. The Nectria/Neonectria radicicola complex has been renamed as the I. radicicola complex after analysis of its multi-gene relatedness and morphological characteristics. The fungi in this complex have been reclassified into 16 species under the genus Ilyonectria based on characteristics analysis Methods and Results: To obtain useful data from the Korean ginseng root rot, I. radicicola was isolated from the rhizosphere soils of the chestnut tree. They were identified through a pathogenicity test and a survey of the morphological features. The existence of I. radicicola in soil samples was confirmed by PCR detections using nested PCR with species-specific primer sets. These were subsequenctly isolated on semi-selective media from PCR-positive soils. Genetic analysis of the I. radicicola complex containing these pathogens was done by comparing the DNA sequences of the histone h3 region. These isolates originating from the rhizosphere soils of chestnut constituted a clade with other closely related species or I. radicicola isolates originating from ginseng or other host plants, respectively. Additionally, the pathogenicity tests to analyze the characteristics of these I. radicicola isolates revealed that they caused weakly virulent root rot on ginseng. Conclusions: This is the first study reporting that I. radicicola isolates from chestnut rhizosphere soils can attack ginseng plant in Korea. Thus, these results are expected to provide informations in the selection of suitable fields for ginseng cultivation.

Background: Dazomet are widely used as soil fumigant to solve soilborne problems, and the degradation intermediates are toxic to nematodes, fungi, bacteria, insects and weeds. Methods and Results: The effects of cultivation of green manure crop, maize before and after soil fumigation on the control of ginseng root rot disease were compared using soil where 6-years-old ginseng was harvested. Fumigant (dazomet) were used for soil fumigation in May and September, respectively. Maize was grown for soil management before and after soil fumigation. After May fumigation, the sowing date of maize was delayed by 15 days and thus its dry weight was decreased significantly. Maize cultivation after May fumigation increased pH but decreased EC, NO3, P2O5, and K significantly. Maize cultivation after May fumigation decreased fungi population and the ratio of fungi and bacteria. Growth of 2-years-old ginseng was improved and the incidence of ginseng root rot was significantly decreased by maize cultivation after May fumigation. After harvesting 2-years-old ginseng, the population of Cylindrocarpon destructans was not different between treatment of May and September, but Fusarium solani showed a significant increase in September fumigation after maize cultivation. Conclusions: Maize cultivation after soil fumigation was effective in inhibiting ginseng root rot by the amendment of mineral composition and microorganism in fumigated soil.

Background : A soil-borne pathogenic fungus, Ilyonectria radicicola (Cylindrocarpon destructans) species complex causing ginseng root rot is the major pathogen on ginseng. DNA extraction from soil is necessary to confirm the presence of ginseng root rot pathogen, I. radicicola. Methods and Results : In order to the increase the detection sensitivity of pathogens present in the soil, the existing soil DNA extraction method was modified to inctease the efficiency of the PCR reaction and to increase the amount of soil samples that can be analyed once by 500 times. For increase the DNA concentration, phenol : chloroform : isoamylalcohol (25 : 24 : 1) were used instead of chloroform : isoamylalcohol (24 : 1), and the sensitivity of PCR was increased by using purification kit. Conclusion : The modified DNA extraction method can detect ginseng root rot pathogen (I. radicicola) with DNA extraction and purification higher than the conventional method.

Background : The soil-borne ascomycete fungus Ilyonectria rdicicola species complex is commonly associated with root rot disease symptoms in ginsneg. Its virulence has been attributed, among other factors, to the activity of hydrolytic cell wall-degrading enzymes (CWDE). Methods and Results : To establish a rapid and accurate detection of Ilyonectria rdicicola, a species-specific primer was developed based on the putative genes of cell wall–degrading enzyme (pectinase, polygalactose, xylanase, xylosidase). Species-specific primer based on the DNA sequences of gene amplified about 200 - 300 bp polymerase chain reaction (PCR) product for Ilyonectria mors-panacis. Conclusion : The primer pair yielded the predicted PCR product size exactly in testing with target pathogen DNAs, but not from the other species of Ilyonectria and species of other phytopathogenic fungi. The primer pair also showed only the species-specific amplification curve on realtime PCR on target pathogen DNA. The detection sensitivity of real time PCR using species-specific primer pair was 10 to 100 times higher than conventional PCR, with 1 to 10 pg/㎕. The approach outlined here could be further utilized as a rapid and reliable tool for the diagnosis and monitoring of the root rot of ginseng.

Background : Replant failure of ginseng is caused by soil-born pathogens causing root rot such as Cylindrocarpon destructans and Fusarium solani. Dazomet are widely used as soil fumigant to solve soilborne problems, and the degradation intermediates are toxic to nematodes, fungi, bacteria, insects and weeds. Methods and Results : The effects of cultivation of green manure crop, maize before and after soil fumigation on the control of ginseng root rot disease were compared using soil of field where 6-years-old ginseng was harvested. Fumigant (dazomet) were used for soil fumigation in May and September, respectively. Maize was grown for soil management before and after soil fumigation. Maize cultivation after May fumigation was delayed the sowing day by 15 days, and the fresh and dry weight decreased significantly. Maize cultivation after May fumigation increased pH but decreased EC, NO3, P2O5, and K significantly. Maize cultivation after May fumigation decreased fungi population and ratio of fungi and bacteria. Growth of 2-years-old ginseng was improved and the incidence of ginseng root rot was significantly decreased by maize cultivation after May fumigation. After harvesting 2-years-old ginseng, the population of Cylindrocarpon destructans was not different among treatments, but Fusarium solani showed a significant increase in September fumigation after maize cultivation. Conclusion : Maize cultivation after soil fumigation was effective in inhibiting ginseng root rot by improvement of mineral composition and microorganism in soils.

Background: The application of crop rotation systems may reduce the occurrence of soil-borne diseases by releasing allelochemicals and by subsequent microbial decomposition. Methods and Results: For reduction of ginseng root rot by the crop rotation system, after harvesting 6-year-old ginseng, fresh ginseng was grown along with continuous cultivation of sweet potato, peanut, and bellflower. Growth of 2-year-old ginseng was significantly inhibited in the continuous cultivation than in the first cultivation. Sweet potato, peanut and bellflower cultivations assisted in obtaining normal yields of ginseng in the first year after the harvest of 6-year-old ginseng. Salt concentration, potassium and sodium contents were gradually decreased, and, organic matter was gradually increased through cirp rotation. Phosphate, calcium and magnesium contents were not altered. The density of the root rot fungus was gradually decreased by the increase in crop rotation; however it was decreased distinctly in the first year compared to the second and third year. The severity of root rot disease tended to decrease gradually by the increase of crop rotation. Conclusions: Short-term crop rotation for three years promoted the growth of ginseng, however root rot infection was not inhibited significantly, although it was somewhat effective in lowering the density of the root rot pathogen.

Background : Ginseng (Panax ginseng C.A. Meyer) is one of the most important medicinal plants in Korea, but its yields are often reduced by a variety of root pathogens. The root rot of ginseng is a destructive soil-borne disease caused by Cylindrocarpon destructans (teleomorph: Ilyonectria radicicola). Methods and Results : Ilyonectria radicicola and its Cylindrocarpon-like anamorph represent a species complex that is commonly associated with root rot disease symptoms on virulence. During the course of this study, several species could be distinguished from I. radicicola sensu stricto based on morphological and culture characteristics. As results of investigated culture characteristics, optimal temperature for mycelial growth of isolates were 20℃, and colony pattern and color were slightly different on PDA. Isolates of I. radicicola were analyzed for their genetic relatedness based on several genes and microsatellite region. I. radicicola group was divided into two small groups. Conclusion : Therefore, we were able to confirm pathogenicity and genetic difference between the isolates in each of the groups of the pathogen. Among these isolates, 21.5% were classified as highly virulent and 78.5% were weakly virulent. *(Corresponding

Background : The fungus Cylindrocarpon destructans (Zins) Scholten is the cause of root rot in many ginseng production areas. Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. Methods and Results : Five kinds of rotation crops, sudan grass soybean peanut sweet potato, perilla were grown for one year in ginseng garden harvested 6-year-old ginseng. The ratio of gram-negative bacteria, fungi, bacteria, total microbial biomass, aerobic/anaerobic microbes were increased by rotational crop cultivation, while the ratio of actinomycetes and the ratio of saturated to unsaturated fatty acids were decreased. The increase in the fungal density or the increase in the proportion of fungi to the bacteria tended to increase the incidence of root rot, but there was no significant difference. The yield of ginseng root showed a highly significant negative correlation with actinomycetes. The correlation between the soil chemical properties and the incidence of root rot was analyzed by cultivating 23 kinds of green manure crops for one year in field where cultivated ginseng continuously. The survival rate of ginseng showed a highly significant positive correlation with soil acidity and a highly significant negative correlation with nitrate nitrogen, and a significant negative correlation with soil salt concentration. Conclusion : Rotation crops improved soil microbial communities, lowered the rate of fungi and increased the proportion of bacteria, the survival rate of ginseng was significantly correlated with soil acidity, nitrate nitrogen and soil salinity.

Background: Some plants have harmful effects on fungi and bacteria as well as plants. Incorporating into soil as green manures are effective in reducing population densities of soil pathogens. Methods and Results: Twenty-three species of green manure crops were cultivated after the harvest of 6-year-old ginseng and then incorporated green manure into the soil at the flowering stage. The following year, the root rot ratio of 2-year-old ginseng and soil chemical properties were investigated. Sorghum sudanense, Helianthus annuus, and Helianthus tuberosus were relatively high in dry matter production. Without incorporating green manure into soil, NO3, EC (electric conductivity) and K were decreased by 95%, 79% and 65%, respectively. When green manure was incorporated to soil, P2O5 and NO3, were reduced by 41% and 25%, respectively. The survived root ratio of 2-year-old ginseng were significantly increased by 56.2%, 47.5%, and 47.3% in Sorghum sudanense, Ricinus communis and Helianthus tuberosus, respectively, In addition, there was a significant increase in Secale cereale, Chrysanthemum morifolium, Atractylodes macrocephala, and Smallanthus sonchifolius. The survived root ratio of ginseng showed a significant positive correlation with soil pH and a negative correlation with NO3, and EC. Conclusion: Cultivation of Chrysanthemum family mainly using rhizome and root as green manure was effective for root rot disease of ginseng.

‘Jungmo1029’, a late-maturing, high biomass and multiple disease resistant rice (Oryza sativa L.) cultivar, was developed for whole crop silage (WCS) use. It was derived from a cross between ‘Gillim collection1’ with high biomass and ‘Junam’ which has some of diseases resistant genes. This elite cultivar had about 127 days growth period from seeding to heading, 105 cm culm length, 11 panicles per hill, 163 spikelets per panicle and 1,000-grain weight of 21.5 g as brown rice. This WCS rice variety was weak to cold stresses similar to ‘Nokyang’ but was tolerant to lodging in the field. In addition, ‘Jungmo1029’ was resistant to leaf and neck blast, bacterial blight except race K3a and rice stripe virus but susceptible to brown planthopper. Its average dry matter yield for three years reached 17.1 MT/ha, 14% higher than that of ‘Nokyang’. This stay green cultivar had good quality for WCS with low acid detergent fiber and high total digestible nutrients similar to ‘Nokyang’.‘Jungmo1029’ was suitable for cultivation in the central and southern plain area of the South Korean peninsula and required to harvest 15~30 days after heading to improve the digestibility of cattle (Registration No. 5104).

온대지역의 벼 품종을 열대지역 재배시 불수출수로 인하여 수확량이 급감하는 경향을 보이는 데 중․만생종이 이러 한 환경변화에 더욱 민감하다. 이러한 장벽을 극복하고자 필리핀 국제벼연구소내 한국지소에서 열대지역에서도 정상적인 생육을 나타내는 ‘진미‘와 밥맛이 좋고 병해에 강한 ‘철원46호‘를 교배하여 열대지역에서도 잘 생육하여 수량성도 높으면서 병에도 강한 온대벼 ‘아세미(수원574호)‘를 개발하였다. 필리핀 현지에서는 간장이 66cm로 작 고 주당수수 12개 수당립수 84개였으며 등숙률을 보면 현지 품종(IR 72)의 등숙률이 63%인데 ‘아세미‘는 77%로 높았고 수확량도 헥타르 당 4∼5 톤으로서, 현지 품종인 ‘IR72’보다 10% 가까이 많았고, 밥맛도 좋았다. 우리나라 에서는 출수기가 8월1일로 ‘화성‘(8월 12일)보다 11일 빨랐으며 간장은 82cm, 수장 21cm, 수수 12개, 수당립수 109 개, 등숙률 83%였고 현미천립중이 22.5g인 중립종이다. 생리장해 저항성으로 유묘적고가 거의 없고 감수분열기 임실률도 높아 내랭성을 어느 정도 갖추고 있었다. 잎도열병 저항성은 보통 수준이었고 흰잎마름병에는 약하나 줄무늬잎마름병에는 강했다. 또한 심복백정도 백미완전미율 등 미질특성은 ‘화성‘과 비슷하였다. 수량성은 중북 부 내륙지와 중서부 해안지에서 ‘화성‘보다 10%정도 높았고 중북부 산간지에서는 ‘오대‘보다 13%높은 수준을 보 였다. 이처럼 ‘아세미‘는 열대지역이나 우리나라에서 잘 재배되는 것으로 보아 아시아 지역에 재배가 가능한 비감 광성 광지역적응성을 갖춘 벼 품종임이 확인되었다.

논 형태를 그대로 유지하면서 쌀 생산 조절 및 조사료 자급률 향상을 위한 방안으로 총체사료벼 연구를 추진하고 있다. 최근의 총체사료벼 품종육성은 기존의 쌀 수량증대를 위한 초다수성 품종 및 계통집단을 활용하여 총체사일리지사료로서 우수한 특성인 경엽다수성, 사료적성, 후기녹체성, 복합내병충성 및 직파적성 등을 가진 품종이 육성되고 있다. 그러나 기존의 다수계 육종재료를 이용하지 않고 사료적성이 우수한 새로운 유전자원을 교배친으로 하여 총체수량성, 후기녹체성 및 복합내병성이 개선된 ‘중모1029호’를 개발하였다. ‘중모1029호’는 총체건물수량이 높고 후기녹체성 및 복합내병성이 개선된 품종을 육성할 목적으로 바이오매스가 큰 ‘길림수집1호’를 모본으로 다수성이며 흰잎마름병 및 줄무늬잎마름병에 강한 ‘주남’을 부본으로 하여 국립식량과학원 답작과에서 2001년에 인공교배하였다. 계통육종법에 의해 세대를 진전시킨 후 고정세대에서 실시한 지역적응시험에서 총체건물수량이 1.70ton/ha로 ‘녹양’ 1.35ton/ha보다 통계적으로 유의하게 26% 증수하였다. ‘중모1029호’는 출수기가 8월29일로 ‘녹양’보다 15일 늦은 만생종이며 초장이 ‘녹양’(109㎝)보다 큰 131㎝로 바이오매스가 큰 장간 품종이다. 흰잎마름병(K1∼K3)과 줄무늬잎마름병에는 강한 반응을 잎도열병에는 중정도의 반응을 벼멸구에는 약한 반응을 보였다. 사료가치는 후기녹체성(SPAD; 22.9)이 ‘녹양’에 비해 높았고 조단백질 6.5%, 산성세제불용섬유소 28.2%, 중성세제불용섬유소 55.0%, 가소화양분총량은 66.6%로 ‘녹양’과 비슷한 경향을 보였다. 금후 본 품종은 건물수량성이 높고 후기녹체성 및 복합내병성이 강화된 총체사료벼 중간모본으로 활용가치가 높은 것으로 판단된다.