• Research in Plant Disease
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• v.9 no.1
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• pp.32-35
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• 2003

Pink rot of potato (Solanum tuberosum L.) occurred at Pyeongchang in Gangwon and at Bosung in Junnam province since 1999. The disease incidence in the surveyed areas was about 5% of harvested potatoes in 2002. Affected tubers showed a dull brown appearance and the lenticels and eyes on tubers turned dark brown. The cut surface of the diseased tuber colored faint pink and the entire surface of the diseased tuber becomes deep salmon pink within 30 min. The pathogen isolated from the diseased tubers was identified as Phytophthora erythroseptica based on morphological and cultural characteristics. Mycelial mat was fairly fluffy, rosette or stellate patterns and rounded or angular hyphal swellings were farmed in water, Temperature for mycelial growth was ranged from 5 to 3$0^{\circ}C$ and optimal temperature was $25^{\circ}C$. Non-papillate sporangia were persistent on stalk and ellipsoid, ovoid, obpyriform or distorted in shape, often with a constriction distal in the middle. Size of sporangia was 41.3~69.6$\times$26.8~47.4 (av, 55.5$\times$37.1) ${\mu}{\textrm}{m}$. Sexuality of Phytophthora erythroseptica was homothallic. Oogonia were 30~46 ${\mu}{\textrm}{m}$ in diameter and oospores were 28~35 ${\mu}{\textrm}{m}$ in diameter, Elongated or cyclindrical antheridia were all amphigynous. This is the first report on potato pink rot caused by Phytophthora erythroseptica in Korea.

• Korean Journal of Weed Science
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• v.5 no.1
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• pp.43-49
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• 1985

This study was conducted to investigate the existance of dormancy in newly collected tubers of Eleocharis kuroguwai Ohwi from paddy fields and to determine the effect of various growth regulators on the bud sprouting and tuberization of E. kuroguwai. The maximum percent sprouting of E. kuroguwai collected at every month during winter was less than 60% regardless of varied collection tunes until 50 days after incubation, suggesting the presence of dormancy in E. kuroguwai tubers. This dormancy was markedly broken as the time went by, probably due to the exposure of tubers the extremly low temperature. The treatment of $BA10^{-3}M$ and $BA10^{-3}+GA10^{-6}M$ increased bud sprouting about 10 and 11 times, respectively, than that of the untreated control indicating that BA seems to be one of the most effective agents among the growth regulators used on the bud sprouting of E. kuroguwai. Foliar application of BA increased tuberization of E. kuroguwai by an average of 34.4% as compared with the untreated control. The highest increase, 39.8% was obtained with BA treatment at $10^{-5}M$.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.219-224
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• 2016

This study was conducted to investigate the ecology of weed occurrence and to establish an economical paddy field weed control system for direct-seeded rice on water. The main problem weed among annual and perennial weeds was Eleocharis kuroguwai. The control effect of E. kuroguwai was low by the application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice in directly seeded paddy fields, but most annual weeds including Echinochloa crus-galli were controlled. Also, the additional application of pyrazosulfuron-ethyl + thiobencarb GR at 20 days after first treatment or of bentazone SL at 43 days after the first treatment effectively controlled E. kuroguwai. Tuber formation of E. kuroguwai was inhibited by the additional application of pyrazosulfuron-ethyl + thiobencarb by 84%, but the dormancy rate of old tubers of E. kuroguwai under the soil was higher than that of E. kuroguwai tubers following single application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice. Tuber formation was inhibited by the additional application of bentazone by approximately 87%, and the old tuber dormancy rate was low in the bentazone treatment. High amounts of old dormant tubers of E. kuroguwai were found in the weedy plots.

• Korean Journal of Organic Agriculture
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• v.10 no.2
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• pp.111-120
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• 2002

This study was conducted to investigate the effect of foliar application of Chitosan and seedling types on increasing the production of fall-growing potatoes(Solanum tuberosum) at the height of 250m from the sea in Jeju Island. The experiment main-plots consisted of four Chitosan applications, and subplots had three seedling types as cutting plug seedlings, mine-tuber plug seedling planting plot and seed potatoes planting plot. The foliar application of Chitosan of 2000ppm was carried out 0, 1, 3, 5 times at intervals of ten days after ten days of transplanting. Plant height and top dry weight were significantly more vigorous as three to five application of Chitosan. In the small tubers(under 80g), the number of tubers and tuber yield were relatively increased in the seed potatoes planting plot and mine-tuber plug seedling plot, but the large tubers(over 80g) was higher in the cutting plug seedling planting plot. T-N content in leaves was increased as the number of application of Chitosan was increased. A similar tendency was shown in K, P Ca, Mg and Na. The growth and tuber yield in cutting plug seedlings, mine-tuber plug seedling planting plot and seed potatoes planting plot were effectively increased as three to five foliar applications of Chitosan was increased.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.55-64
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• 2002

This study was carried out to determine agronomic and genetic characteristics of the production process in tropical yams(Dioscorea alata L.). To make clear the possibility of cultivation of tropical yams in the Suwon area, the growth of the aboveground parts and the enlargement of tuber of Dioscorea alata, were investigated. The aboveground parts of the plants whose sprouted mother tuber were planted in late April were grown slowly until the 70-days after planting and grown rapidly after. From about 50-days after plantation, total length of vines slowly decreased due to the burning of the branch vines of lower modes. With regard to the branching progressed to 4th for the solo yam and to 6th for purple yam. The secondary branches tended to grow better. When the formation of daughter tubers was observed at the 50-days after planting, their enlargement was very slow. The rapid growth of tubers began at the 40-days and continued to the 90-days. General components such as protein, fiber, and lipid were higher in D. opposita rather than in D. alata. Hardness of D. alata was 2696.2 while that of D. opposita was 4946.9. Lightness of D. alata was 73.99, being higher than that of D. opposita.

• Journal of Practical Agriculture & Fisheries Research
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• v.6 no.1
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• pp.50-62
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• 2004

Tuber yield and content of general component and diosgenin which is a main bioactive property were investigated in order to determine the growth characteristics of round typed yam(Dioscorea opposita L.) and the potential of artificial culture at Suwon, Korea. Tubers of round yam was initiated to form at 60 days after planting and then enlargement of tubers lasted by 160 days after planting. Compared to short typed yam(108g), tuber weight of round yam was higher(127g) on the basis of dry weight at 200 days after planting. In comparison of general component between round yam and short yam, protein of round yam(3.62%) was higher than short yam(2.10%). Water content in round yam(64.5%) was lower in short yam(79.4%), indicating a higher dry weight ratio of round yam. Hardness of round yam was 2787.6 while short yam showed about two times higher hardness(4946.9). Lightness was higher in round yam(77.4). In tuber extracts analysis, diosgenin content was respectively 3.32% in round yam and 2.61% in short yam.

• Natural Product Sciences
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• v.6 no.2
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• pp.53-55
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• 2000

In the course of continous work for the discovery of anti-thrombotic constituents from tubers of Gastrodia elata, citric acid 1,5-dimethyl ester was isolated from ethylacetate soluble fraction prepared from the methanol extract. The structure of the compound was determined by the spectroscopic data. The anti-thrombotic effect of this compound was observed with prolonging the bleeding time in thrombin-induced thrombosis model of mice.

• Korean Journal of Pharmacognosy
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• v.7 no.4
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• pp.241-245
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• 1976

Spectrophotometric determination of aconitine at 231 $m{\mu}$ was carried out. By this means, content of poisonous alkaloids in several tubers of Aconitum spp. on Korean market and natural product of Korea were determined.

• Natural Product Sciences
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• v.3 no.2
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• pp.104-105
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• 1997

In the course of continous work on tubers of Gastrodia elata, a new constituent was isolated from the ethyl acetate soluble fraction prepared from the methanol extract. The structure of the compound was identified as ${\alpha},{\alpha}'-[bis-2-(5-carboxaldehydo)furanyl]-dimethyl$ ether from the elemental analytical and spectroscopic data. This compound was once isolated from Cirsium chlorolepis and named as cirsiumaldehyde. This is the first furan type compound isolated from Gastrodia elata.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.91-92
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• 1997

In the course of continous work on tubers of Gastrodia elata, a new constituent, 4, 4$^{I}$-dihydroxybenzyl sulfoxide was isolated from the ethyl acetate soluble fraction prepared from the methanol extract. The structure of the compound was identified from the elemental analytical and spectroscopic data in comparison with those of non-substituted benzyl sulfoxide.e.