• Research in Plant Disease
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• v.21 no.3
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• pp.231-234
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• 2015

Elsinoe fawcettii and E. australis are two currently recognized scab pathogens of citrus. E. fawcettii has at least six pathotypes while E. australis has at least two pathotypes. Colonies of E. fawcettii and E. australis do not sporulate in artificial media including potato dextrose agar (PDA). Whiteside's method has been widely used for preparing conidial inoculum in vitro. This study was carried out to develop efficient method for conidia production from artificial media. We developed a shaking method which included the following steps: 1) Colony grown on PDA was mashed with a steel spatula; 2) Mycelia fragments were cultured in 50 ml sterilized rain water in a rotary shaker-incubator (180 rpm) at $25^{\circ}C$ for 24 h: 3) The conidia suspension was filtered through two layers of cheesecloth. Average conidia production of all isolates tested using this shaking method was approximately 13.1 times higher than that from Whiteside's method in this study.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.309-309
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• 2017

The experiments were carried out in open experimental field of Field Crops Research Institute, Hai Duong, Vietnam in Winter Spring seasons 2015-2016 and 2016-2017 for finding high yielding of Korean chipping potato varieties which are adaptable to Vietnam condition. Six varieties of Korean potato (G1, G2, G4, G10, B1, B2) were experimented. The control variety (G6) was Atlantic which has long been a standard chip variety. The results showed that, for a hill, there was positive correlation between number of stems and number of tubers. The hill yield also showed highly relation to the plant height and number of tubers. Even though the growth and yield of potatoes grown in the season 2016-2017 were significant higher than these of potatoes grown in the season 2015-2016, their percentages of tubers infected by scab disease were much higher. This is probably because of irregular soil moisture content at the tuber forming duration. While G1, G6 and B1 are white flesh varieties, the remaining are yellow flesh varieties. There are two shapes types among experimented varieties: oblong (G1, G10, B1) and round shape (G2, G4, G6, B2). The total yields of varieties G1, G2, B1, B2 were higher than the total yield of the control variety from 16.5-49.4% in the season 2015-2016 and from 39.8-75.6% in the season 2016-2017.

• Korean Journal of Organic Agriculture
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• v.7 no.1
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• pp.79-90
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• 1998

This study was conducted to effect promotion of fall potato growth in the place which green manual crops had been previously cultivated, crushed and tilled and polyethylene transparent vinyl had been mulched from Aug. 5 to Aug. 29 in 1997. The maximum temperature of below-ground at the depth of 10cm was $42^{\circ}C$ during the mulching period, and the pH and the organic compound content of soil was very increased by the cultivation of green manual crops and the mulching of polyethylene transparent vinyl. The total yields of green manual crops which had been previously cultivated were as the following orders; the hybrid of sudan grass, soybean, alfalfa, otherwise, fresh weight of stems and the tuber yield of fall potato were significantly affected in the plot of soybean + fall potato after the soil solarization with the mulching. As these results, it was possible to improve crops growth and to sterilize soil by the mulching treatment of polyethylene vinyl after cultivation of green manual crops during the high temperature of the summer season.

• Research in Plant Disease
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• v.22 no.1
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• pp.18-24
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• 2016

This study was conducted to elucidate the cultural and pathogenic characteristics of Cladosporium cucumerinum PT1 and resistance of 81 commercial cucumbers (Cucumis sativus). Cucumber leaves and fruits appeared as scab were collected from a plastic film house located in Pyeongtaek, Gyeonggi-province, Korea in late March, 2015. A casual fungus was isolated from the diseased fruits on potato dextrose agar and it was identified as C. cucumerinum PT1 based on the morphological characteristics. To find out the effect of wounding and fruit size on the development of cucumber scab, small (<10 cm long), medium (10 to 20 cm long), and large (>20 cm long, commercially mature fruit) size cucumber fruits were harvested, C. cucumerinum PT1 pathogens were inoculated with a single droplet of suspension ($1{\times}10^5$ spores/ml) on wounded or unwounded cucumber fruits. Small fruits were completely damaged with showing severe water-soaking symptoms and fast pathogen growth regardless of wounded or unwounded. Meanwhile slight water-soaking symptoms on medium and large size fruits occurred and disease development into plant tissues was observed only on wounded fruits. Disease resistance of 81 commercial cucumber cultivars was evaluated on third-stage seedlings and small fruits by inoculating suspension ($1{\times}10^5$ spores/ml) of C. cucumerinum PT1. As a result, mini and pickling cultivar groups were resistant, 'Cheoeumcheoreom' cultivar was symptomless and the other cultivars were resistant to medium resistant. On the other hand, most of cucumber cultivars belonging to the other groups were susceptible. Disease resistance of cucumber against cucumber scab was significantly different among cultivars and a few cucumber cultivars showed different disease resistant responses to two bioassay methods using seedlings and small fruits. Therefore, to screen scab resistance in cucumber, a test using both fruits and seedlings is advisable. We think that the selected resistant cultivars can be used to control cucumber scab effectively under the farmhouse condition.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.247-254
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• 2011

The agronomic characteristics, nutritional contents, and insect response of the potato clones transformed with a glufosinate ammonium resistance gene were evaluated. Among the 4 transgenic potato clones, the Bar 3 clone was selected as a promising one for commercialization. The Bar 3 clone showed similar tuber yield capacity but higher herbicide resistance as compared with the non-transgenic potato cv. Dejima. The herbicide resistance of the Bar 3 clone was more than 5 times higher when tested with the herbicide concentration recommended by the producer. The major agronomic characteristics of the Bar 3 clone were not different from those of the non-transgenic Dejima. The annual variation in yields and agronomic characteristics showed similar tendency for 2 years from the third to fourth generation after transformation. The tubers of the Bar 3 clone also showed low occurrence in common scab and physiological disorders such as cracking and secondary growth. But the reasons for such results are yet to be studied. Also, it was considered that the Bar 3 clone have a potential of reducing not only common scab occurrence but also soil erosion during potato cultivation in field. The nutritional contents (mineral compound, vitamin C and amino acid) and response to Spodoptera exigua of the transgenic potato clones were not significantly different.

• Korean Journal of Organic Agriculture
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• v.10 no.1
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• pp.75-86
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• 2002

This study was conducted to investigate the effects of pig manure composting using starch pulp m growth and yield characteristics of potato cropping. Four treatments ; No compost, 1 : 1 : 0, 1 : 0.75 : 0.25 and 1 : 0.5 : 0.5 the mixing ratio of pig manure, saw dust, and dehydrated starch pulp and composting by Piling and blowing methods. Plant heights in first growth stage were higher for the treatment of saw dust compost and starch pulp compost than the treatment of chemical fertilizer, but after the stage, there were no significant difference among treatments. The number of stolons were met for 10.9 in 1 : 0.5 : 0.5 treatment, following 1 : 0.75 : 0.25 and 1 : 1 : 0. On the other hand, tuber diameter and top dry matter weight tended to be larger for manure treatment than no treatment but there was no significant difference. Total number of tubers were largest for 1 : 0.5 : 0.5, and those for 1 : 1 : 0 and 1 : 0.75 : 0.25 were similar. Tuber yields of not more than 80g tended to be different, but those of between 81g and 120g and more than 120g were apparently larger for the compost treatment than no treatment. The ratio of marketable tubers appeared large to be about 86% for 1 : 0.75 : 0.25 and 1 : 0.5 : 0.5 treatments. Ratio of infected common scab on potato tubers tended to be highest for 1 : 0.5 0.5 but there were no statistical significance. However, when compost was made by mixing starch pulp in future, the solutions to the occurrence of infected common scab must be considered, The contents of N. P, K and Ca in leaves were larger for the compost treatment than no treatment, but no significant difference was observed, Accordingly, the effects of treating starch pulp compost on growth and yield characteristics of potato cropping were more affirmative than those of saw dust compost.

• Korean Journal of Plant Resources
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• v.16 no.3
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• pp.264-274
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• 2003

Many potato genetic resources have been collected and improved for their diverse traits over the years using breeding program in KPGR. To select potential varieties for table and processing in Korea, 58 elite potato breeding lines and several 'Valley' varieties were cultivated and harvested at Korea Alpine area in 2001. The cultivated lines and varieties were evaluated using their cultural adaptability in the environment and tuber characteristics, such as the depth of tuber eye, tuber shape, skin color, flesh color, scab resistance, yield, and the resistance of hollow heart and internal brown spot disease. Additionally, in the selection of potential processing varieties, reducing sugar content (sum of glucose and fructose concentration) of tubers is critically considered, because it mainly influence on the chip color of processing potato tuber. For table stock varieties with white skin color, 'Early Valley', 'Summer Valley', 'Winter Valley', and 'Taebok Valley' were selected. In the aspect of diverse potato tuber color, several varieties were selected such as 'Golden Valley' for its yellow fresh and skin color, 'Gogu Valley', 'Juice Valley', and 'Rose Valley' for their red skin color, and 'Purple Valley' for its purple skin. Compared with world wide known processing cultivar 'Atlantic', 24 lines (or varieties) were selected for the potential potato processing industry due to their low reducing sugar contents (below 0.3％), high yield (above 4.0 ton/ha), and unique chip colors. Selected white chipping varieties were 'Taedong Valley', 'Kangshim Valley', and 'Kangwon Valley', which have 0.23％, 0.27％, and 0.29％ of reducing sugar contents, respectively. 'Bora Valley', having deep purple color in both skin and fresh, was selected for purple chip variety and has 0.26％ of reducing sugar content. Light yellow chip varieties (lines) were 'Rose Valley' and Valley 54, having 0.19％ and 0.269％ of reducing sugar content, respectively. For French frying potatoes, 'Stick Valley' of 0.22％ and Valley 72 of 0.151％ in reducing sugars were selected. All of these selected lines and 'Valley' varieties can be used as parents to improve potato genetic resources and to develop better varieties with unique traits and colors.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.115-126
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• 2004

The actinomycete strain PK-A41 was isolated from a soil sample from pepper fields in Ko-yang, Korea. The strain PK-A41 inhibited the mycelial growth of some plant pathogenic fungi and oomycete, Alternaria mali, Colletotrichum orbiculare, Fusarium oxysporum f.sp. lycopersici, Magnaporthe grisea, Rhizoctonia solani, and Phytophthora capsici. The presence of LL-diaminopi-melic acid in the cell wall extract and the nucleotide sequence of the 16S rDNA region of the strain PK-A41 was assigned to Streptomyces scabiei. Further morpho-logical, biochemical, and pathological analyses also confirmed the strain PK-A41 to be S. scabiei, which is pathogenic to potato tubers. The maximum antibiotic production of the strain PK-A41 was achieved when grown on the glycerol peptone broth (GPB) medium for 9 days.

• The Korean Journal of Pesticide Science
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• v.13 no.1
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• pp.45-53
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• 2009

An antagonistic bacterial strain KLF01 was isolated from rhizosphere of tomato and identified to be Lactobacillus sp. by biochemical and genetic analysis. This strain showed antagonism against the used plant pathogenic bacteria like Ralstonia solanacearum, (bacterial wilt), Xanthomonas axonopodis pv. citri, (Citrus canker), Xanthomonas campestris pv. vesicatoria (Bacterial spot), Eriwinia pyrifoliae (Shoot-blight) and Eriwinia carotovora subsp. carotovora group (Potato scab) through agar well diffusion method. In planta test done by drench application of strain KLF01 $(4{\times}10^8 cfu/ml)$ into the experimental plot containing tomato (Solanum lycopersicum L.) cultivar 'Lokkusanmaru' and red pepper (Capsicum annuum L.) cultivar 'Buja' plants, in pot test post-inoculated with the plant pathogenic bacteria, R. solanacearum significantly reduced the disease severity, compared to the non-treated plants.

• KSBB Journal
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• v.25 no.2
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• pp.167-172
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• 2010

Streptomyces scabiei producing phytotoxin called thaxtomin, which cause scab disease on economically important crops such as potato. For molecular genetics study of S. scabiei an effective transformation method was established based on conjugal transfer from Escherichia coli ET12567 (pUZ8002) using a phiC31-derived integration vector, pSET152, containing oriT and attP fragments. The high frequency was obtained on MS medium containing 50 mM $MgCl_2$. In addition, the sequence and location of the chromosomal integration attB site of S. scabiei was identified for the first time in the strains producing thaxtomin by the southern blot analysis of exconjugants and the sequencing of plasmid containing DNA flanking the insertion sites from exconjugant chromosome. Similar to the case of Streptomyces species, a single phiC31 attB site of S. scabiei is present within an ORF encoding a pirin-homolog.