• Research in Plant Disease
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• v.20 no.1
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• pp.25-30
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• 2014

Phytophthora infestans was isolated from potato leaves collected from main potato producing areas in Korea during 2009-2011. In 2009, 99 isolates tested were all A1 mating type. Two of 64 isolates in 2010 and two of 78 isolates in 2011 were A2 mating type and they were found only in Miryang area. Among 99 isolates examined in 2009, 13.1% was resistant to metalaxyl, 3.1% was intermediate resistant and 83.8% was sensitive. In 2010, 19.4% of 62 isolates was resistant, 4.8% was intermediate and 75.8% was sensitive. Metalaxyl resistant, intermediate and sensitive isolates collected in 2011 were 23.1%, 9.0% and 67.9%, respectively. Metalaxyl resistant isolates increased mainly in winter cropping areas and seed potato producing areas where fungicides were sprayed more often. Frequencies of isolates showing minimum inhibition concentration of dimethomorph at $1.0-5.0{\mu}g/ml$ were 17.2% in 2009, 19.0% in 2010 and 15.4% in 2011. However, there was no evidence for occurrence of resistant isolate to dimethomorph because no isolate was able to grow at $5.0{\mu}g/ml$.

• Korean Journal of Agricultural Science
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• v.39 no.1
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• pp.117-123
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• 2012

Pathogenic fungi and bacteria such as Pectobacterium atrosepticum, Clavibacter michiganensis subsp. sepedonicus, Verticillium albo-atrum, and Rhizoctonia solani were the major microorganism which causes diseases in seed potato during postharvest process. Current detection method for disease-infected seed potato relies on human inspection, which is subjective, inaccurate and labor-intensive method. In this study, a reflectance spectroscopy was used to classify sound and disease-infected seed potatoes with the spectral range from 400 to 1100 nm. Partial least square discriminant analysis (PLS-DA) with various preprocessing methods was used to investigate the feasibility of classification between sound and disease-infected seed potatoes. The classification accuracy was above 97 % for discriminating disease seed potatoes from sound ones. The results show that Vis/NIR reflectance method has good potential for non-destructive sorting for disease-infected seed potatoes.

• Research in Plant Disease
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• v.19 no.2
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• pp.90-94
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• 2013

Potato cv. 'Haryeong' was bred with high solids, resistance to late blight and good culinary quality. It has been registered as new potato variety in 2005. Tuber necrosis symptoms such as severe superficial necrosis, raised surface lesions and ringed necrotic areas were found in tubers of 'Haryeong' during storage of seed potatoes in 2010. Potato virus Y (PVY) was detected from these symptomatic tubers by the analysis of RT-PCR using a primer set specific to coat protein gene of PVY. The nucleotide sequence of RT-PCR product ($PVY^{Hkr}$) was determined and compared to those of other strains, such as $PVY^{Kor}$, $PVY^N$, $PVY^{NTN}$, $PVY^O$, and $PVY^C$ registered in GeneBank. The result showed that $PVY^{Hkr}$ was exactly the same as $PVY^{Kor}$, Korean isolate reported in 2005, except two nucleotides. To verify the PVY was responsible for the tuber necrosis symptoms shown in the tubers of 'Haryeong', a bioassay was done using two viruses (PVY and Potato leafroll virus) and five potato cultivars ('Haryeong', 'Superior', 'Atlantic', 'Dejima', and 'Chubaek'). As expected, the same necrosis symptom appeared in tubers of 'Haryeong' infected with PVY only during the storage period.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.18-25
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• 2001

Ethanol extracts from 46 plants were tested for their fungicidal activity against six plant diseases consisting of Maynaporthe grisea, Rhizoctonia solani, Botrytis cinerea, Phytophthora infestans, Puccinia recondita, and Erysiphe graminis in the greenhouse studies. Strong activity at 5 and 10 mg/pot was produced from the extracts of Helianthus annuus flowers and Zea mays leaves against P. grisea. In a test with B. cineara, extracts of H. annuus leaves, H. annuus flowers, Chrysanthmum coronarium var. spatiosum, Cucurbita moschata seeds, Lycopersicon esculentum, Z. mays, and Z. mays leaves had strong activities at 5 mg/pot. In a test with P. recondita, strong activity was obtained from the extracts of Capsicum frutescens, C. moschata seeds, H. annuus seeds, L. esculentum, and Malva veticillata at 5 mg/pot. Against E. graminis, extracts of Cucumis sativus, H. annuus seeds, Salanum tuberosum, Z. mays, and Z. mays leaves produced strong activities at 10 mg/pot. All the extracts were ineffective against P. infestans and R. solani. Among seven extracts tested, the extracts of H. annuus leaves and flowers were highly effective against all the strains of B. cinerea resistant to carbendazim, procymidone, and diethofencarb. Furthermore, potent fungicidal activity was produced from the extracts of C. coronarium var. spatiosum and C. moschata seeds against the SSR, SRR, and RSR strains of B. cinerea, and Z. mays and Z. mays leaves against SSR and RSR. Extract of L. esculentum showed very strong activity only against RRS of B. cinerea.

• Journal of Biosystems Engineering
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• v.23 no.4
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• pp.373-380
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• 1998

The contribution of this paper is to provide the methods for the production automation of potato microtuber using the vision process in growth monitoring. The first method deals with computation for the growth density in the primary growth process. The second method addresses cognition process to identify the number and the volume of potato microtuber in secondary growth process. The third is to decide whether potato microtubers are infected by a virus or bacteria in growth process. The computation for the growth density in the primary growth process uses the method of Labeling. The second and third methods use template matching based on color patterns. With the developed method using vision process, this experiment is capable of discriminating weekly growth-rate in primary growth process, 85% cognition rate in secondary process and identifying whether there are infections. Therefore, we conclude that our experimental results are capable of growth monitoring for mass production of potato microtubers.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.252-256
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• 1998

A Study was conducted to investigate comparison of in vitro tuberization between normal and transgenic potato plantlets harboring adenosine deaminase gene in potato cultivar of Desiree. In time course study of in vitro tuberization, the rate of tuberization in four lines were increased till 6 weeks. but maintained stil after 7 weeks. Microtuber initiation of transgenic lines, 43 and 39 were faster than other lines, but no difference was observed after 5 weeks compared with normal plantlets. In all transgenic lines, the majoirty of microtubers produced were small(less than 100 mg) and medium(100-200mg) size rather than large size(more than 200 mg). Among 4 lines , line 9 produced the highest number of microtubers per each culture vessel. The results of this experiment suggest that there is no significant difference in microtuber production efficiency between normal and transgenic potatoes.

• Korean journal of applied entomology
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• v.13 no.4 s.21
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• pp.227-231
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• 1974

During the period from 1971 to 73 physiologic races of potato late blight pathogen, Phytophthora infestans, causing severe losses of seed potato production at Alpine area, Korea, were investigated. In 1971, 68 isolates of the pathogen from various potato varieties were identified by the use of differential host Plants, and found that there were 10 races; 0, 1, 2, 3, 1.3, 1.4, 3.4, 1.3.4, 2.3.4. The most Predominant races for the year were 0 and 3. In 1972, the same procedure was repeated with 62 isolates of the pathogen, and found 5 different races; 0, 1, 4, 1.3 and 1.3.4. The most predominant race for the year was race 0. In 1973, six races; 0, 3, 4, 1.3, 3.4 and 1.3.4 were found from 76 isolates of the year, and the race 0 and 4 apperared as the most Predominant races for the year. Total of 11 races; 0, 1, 3, 4, 1.3, 1.4, 3.4, 1.3.4, 2.3.4 and 1.2.3.4, were found during the period from 1971 to 73 at Alpine area, among which the most predominant races were race 0, 3, and 4. The investigation indicated that the anual incidence of these races largely depended on the climatic conditions of the year.

• Food Science and Preservation
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• v.16 no.4
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• pp.490-498
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• 2009

This study attempted to examine the profitability and marketing costs of seed potato under contract farming system of BADC (Bangladesh Agricultural Development Corporation) with the help of primary and secondary data. Total 45 contract farmers were randomly selected. Attempts were made to calculate costs, returns and profitability of seed potato production under contract farming system, and to identify marketing channels of seed potato. The field level data were collected by a farm survey during the months of April 2005 through direct interviews with contract farmers and registered dealers using a structure survey questionnaire. The results showed that the gross return per hectare was Tk. 252,464 for all categories of farms. Cost of seeds, fertilizers, pesticides, irrigation and human labor were critical inputs for profitability of seed potato. Cobb-Douglas production function analysis was used to determine the effects of the key variables to seed potato production under contract farming system. The elasticity of seed potato production was at 0.727 for all categories of farms. The findings exhibited that the summation of elasticity of different inputs for seed potato production was less than one, implying that the production function exhibited decreasing returns to scale. Registered dealers and Upazila Sales Centers were involved in seed potato marketing formed a straightforward marketing channel. The total marketing costs of registered dealers were Tk. 759.49 per ton of seed potato. The net marketing margin of registered dealers was estimated at Tk. 465.51 per ton of seed potato. The selected contract farmers and registered dealers faced a number of problems and some of recommendations were suggested.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.150-158
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• 1996

The potato has been used as a part of key staple foods in Korea. Recently, the demand for the potato tends to increase due to its nutritional Quality, and the Quantity of imports has rapidly been increasing. Contamination of seed potato by pathogens especially could cause a severe reduction of total production. In order to solve the problem, Korea Research Insistute of Bioscience and Biotechnology(KBIBB) developed the new commodity called a "potato microtuber". Before its production and distribution, researches on new commodity should be undertaken in many aspects, especially in terms of economic aspects. The main objectives of this study are to measure the economic value of the potato microtubers and to forecast its spreading effects and to examine the Contingent Valuation Method(CVM) could be accepted in the economic analysis for a new agricultural product, here in potato microtubers. Through the regression results, the consumer behavior analysis had performed for potential users of potato microtubers, and through the demand function derived by the consequence of functional relationship, consumer's surplus was estimated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.468-476
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• 2020

This study was performed to establish light intensity conditions for producing stem cuttings for aeroponic systems suitable for seed potato production using a closed-type plant production system. Shoot tip cultured plantlets of 'Sumi' and 'Chubaek' potato (Solanum tuberosum L.) were acclimatized, cuttings were collected, and stem cuttings were planted. The seedlings were raised for 40 days at different LED light intensities (60, 120, 180, and 240 μmol·m^-2·s^-1), and were cultivated in an aeroponic system for 80 days. When stem cuttings were raised at 60 μmol·m^-2·s^-1 LED light intensity, the plant height was the longest, at 17.3 cm for 'Sumi' and 16.1 cm for 'Chubaek', and the number of nodes was the highest in both cultivars. The higher light intensities, produced smaller plants with fewer nodes. The leaf areas, SPAD values, and Fv/Fm values differed slightly between cultivars. The fresh weight of stem cuttings, and the production rate of healthy stem cuttings were the highest at 60 μmol·m^-2·s^-1. In the aeroponic system, seedlings raised at 60 μmol·m^-2·s^-1 with LED light intensity showed a difference between the cultivars, but the fresh weight of stems and leaves above the planting plate was the heaviest. In addition, below the planting plate the stem cuttings were longest and the root weight was heaviest at 60 μmol·m^-2·s^-1 LED light intensity. The number of stolons also differed between cultivars, but was greatest for seedlings raised at 60 μmol·m^-2·s^-1 LED light intensity, at 4.2/plant for 'Sumi' and 7.7/plant for 'Chubaek'. At 60 μmol·m^-2·s^-1 LED light intensity, the tuber number and total tuber weight were the best, but the higher the light intensity, the smaller the total tuber number and total tuber weight for both cultivars. In conclusion, when producing potato stem cuttings for aeroponic systems using a closed-type plant production system, the most suitable LED light intensity for raising seedlings was found to be 60 μmol·m^-2·s^-1.