• Research in Plant Disease
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• v.12 no.1
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• pp.1-4
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• 2006

During visiting North Korea from 2001 to 2005, I have had a few chances to observe and discuss several North Korean scientists for the seed production program and also, the occurrence of potato pests. Healthy seed production, especially in the early generations, e.g. the production of virus-free starting materials as well as in vitro pre-basic seeds (G0) by hydroponics and basic seeds under netted houses according to her new national seed potato program of Academy of Agricultural Science, Pyongyang, North Korea, has been done well so far. Some major pests occurred, however, in the early generations such as pre-basic seed (G0) in greenhouse, basic seed (G1) in screenhouse, foundation seed-I (G2) and even ware potatoes in the fields are Phytopitthora infestans, Spongospora subterrunea, Ralstonia solanacearum, Pythium spp. and some viruses such as Potato virus X, Potato virus Y, Potato leafroll virus, and also larger potato ladybeetle, greenhouse whitefly and potato tuber moth. Therefore, the success of healthy seed production in North Korea will be thoroughly depended on the pest control and the multiplication of virus-free seed stocks in the isolated areas, especially where no infected potatoes are grown.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.221-227
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• 2004

Protocol was established for production of virus free healthy seeds using meristem ($0.3-0.5\;\cal{mm}$ in size) culture and field management under net house condition in tomato. The isolated meristem was found well established in MS liquid medium containing $0.1\;\cal{mg}\;1^{-1}\;of\;GA_3$. For shoot and root development either from primary meristem or from nodal segment of meristem derived plants, semisolid MS medium having $0.5\;\cal{mg}\;1^{-1}$ of IBA was found most effective. The elimination of the studied viruses (ToMV, CMV, ToLCV) in meristem-derived plants was confirmed by DAS-ELISA test. For field management of the virus eradicated meristem-derived plants, use of net house was found very effective measures to check viral vector visit and eventually infection. The meristem-derived plants were vigor and high yielder than the native seed derived plants and produced healthy seeds. Due to stop vector visit, no viral symptoms were observed in both $R_1\;and\;R_2$ plants cultivated in net house condition. Starting of viral infestation was observed in $R_2$ generation when they were planted in open house condition without control of vector visit. Therefore, for management of viral diseases, use of virus free meristem derived plantlets and their subsequent cultivation in soil under net house condition without using any vector killing insecticide can be recommended for producing healthy seeds in tomato. The developed protocol for environmentally healthy tomato seed production in Bangladesh may be used in the countries having similar tropical like environment conducive for viral vector visit.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.44-51
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• 1995

This investigation was conducted to determine the effect of the optimum planting date and place for good seed production on growth variation, grain yields, different of variety, infection of seed by fungi, and seed germination and vigor after room storage. Early maturity Korean soybean variety, Keunolkong, and introduced vegetable soybean variety, Fukura-edamame, were planted at field of YAES. and high cool land of Sajapyong in Milyang（altitude, 850m） on May 15 （early）, June 15 （mid.）, and July 15 （late） in 1991. The emergence and vegetative period gradually increased in the early planting date. The grain yield, seed weight, pod number, healthy grain yield also increased when Keunolkong was planted on early date. The healthy seed rate, Keunolkong increased in the early planting date, whereas that of Fukura also increased in the late planting date. Infection ratio of grain to phomopsis seed decay （Phomopsis spp. ' Diaporthe phaseolorum） in Fukura steadily increased in the early planting date. Infection ratio of grain to purple seed stain （Cercospora kikuchii） generally increased in the mid and late planting date. The seed germination and seedling vigor after room storage from five to six months gradually increased in the late planting date. And seed germination of Fukura rapidly decreased in the early planting date. Therefore, the optimum planting date for good seed production in early maturity vegetable soybean was June 15 in terms of harvesting time avoid a high temprature and humidity.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.222-227
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• 1994

Effects of field applications of benomyl on Phomopsis seed decay of early soybeans were investigated at Suwon in 1992 and 1993. Pod and immature seed infections were markedly suppressed by benomyl application at the R6 stage whereas the spray at the R7 stage was not as effective as the spray at R6. When compared with unsprayed plots, benomyl spray at R6 resulted in decrease in Phomopsis seed infection by 37.1% and 73.9%, and increased in frequency of seed germination by 1.8% and 8.0% in 1992 and 1993, respectively. The results indicated that only one spray at early R6 could effectively reduce seed infection by Phomopsis spp.and could be adopted in a disease management program for commercial production of healthy soybean seeds.

• Research in Plant Disease
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• v.12 no.1
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• pp.28-31
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• 2006

One of major potato viruses is Potato virus Y (PVY) in Korea. In the southern part of Korea, potatoes have been grown as double crops in a year by using cv. 'Dejima' and 'Chubak' due to very short dormancy. However, they have caused a serious problem such as a rapid degeneration. It has been thought that the degeneration is affected by the high incidence of PVY in neighboring potato fields. Therefore, the investigation of factors causing the degeneration is very important in the production of healthy seed potato. In this study, the PVY reinfection rates of several potato varieties and the different seed sources of cv. 'Chubak' have been investigated. Results show that the lowest infection rate of PVY among four potato cultivars derived from minitubers is cv. 'Superior'. The others are in order of 'Dejima', 'Atlantic' and 'Chubak'. Also, the incidences of PVY differ significantly when several seed sources are examined. When the seed potatoes (G2, the progeny of microtuber) as spring potato crops are planted in area without potato field nearby, the infection rate of PVY is as low as that of microtubers. However, PVY incidence in the progenies of minitubers as fall potato crops largely increases. Therefore, the best way of potato production under double cropping system is to use the healthy seed potato produced in area without potato field and plant relatively resistant cultivar such as Dejima.

• Journal of Environmental Science International
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• v.24 no.6
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• pp.755-762
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• 2015

The present study was conducted to develop seed treatment for the production of healthy and clean peanut sprout. Dry heat treatment of peanut seeds reduced the incidence of the rot. The seed treatment condition at $52^{\circ}C$ for 10 h. was the most efficient without inhibiting seed viability significantly. Seeds were dark cultured at $27^{\circ}C$ for up to 9 days. The treatment of Indole-B and gibberellic acid influenced germination, T50, fresh, dry weight, hypocotyl length, hypocotyl length diameter, root length, number of lateral root and epicotyl of peanut sprout. There were no differences in the germinability of peanut seeds between gibberellic acid treatment methods but higher fresh weight was observed in the GA3 solution spray after 2 hour water soaking. The general growth and lateral root development of peanut sprouts were suppressed by Indole-B which is used for inhibiting root formation and promoting hypocotyls. The treatment of gibberellic acid promoted hypocotyl elongation, but it did not influence on the growth of hypocotyls and root system.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.3
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• pp.207-216
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• 2010

Individual differences of ozone ($O_3$) resistance for seed production, seed germination and seedling development were examined in this study. Five in each healthy and damaged trees of Pinus thunbergii growing in air polluted area for 12 years were chosen based on visible foliar injury and growth. The cones of P. thunbergii, which were collected from healthy and damaged trees, were analyzed for physical characteristics and seeds from the cones were used to test germination percentage under $O_3$ treatment. The germinated seeds were continuously exposed to $O_3$ treatment and the lipid peroxidation and activities of antioxidative enzymes were determined for both seeds and seedlings. The $O_3$ treatment for seed germination and seedling development were conducted at three conditions: control, 150 ppb and 300 ppb of $O_3$. The non-treated seeds from the damaged trees showed 21.6% lower germination than those from the healthy ones. On the $O_3$ treatment of 300 ppb, seed germination decreased approximately 10% for the healthy trees and 19% for the damaged trees compared to that on the control. The seeds from the healthy trees showed significantly higher activities of superoxide dismutase (SOD), glutathione reductase (GR), and catalase (CAT) than those from the damaged trees. The activities of GR, ascorbate peroxidase (APX), and CAT decreased along with the increasing $O_3$ concentration in two tree grades. Malondialdehyde (MDA) content of seeds was not influenced by $O_3$ treatment for two tree grades. In seedling development, there were no significant differences for length and biomass of needle and root of two tree grades at both the control and 150 ppb of $O_3$. At 300 ppb of $O_3$ treatment, however, the length and biomass of needle and stem decreased for two tree grades but no significant differences was detected in root. The seedlings from the damaged trees were more sensitive to the $O_3$ treatment, showing higher activities of SOD, APX, and CAT and content of MDA compared to those from the healthy tree seedlings. Our results indicate that seed germination and seedling development are vulnerable to increasing $O_3$ concentrations and that attention must be paid to the individual selection of tree species for reforestation.

• Korean journal of applied entomology
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• v.16 no.3 s.32
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• pp.163-170
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• 1977

Potato diseases, especially mosaics and leaf roll, appear to reduce potato yield in Korea more than any other factor. A seed potato certification program was established at the Alpine Experiment Station (AES) in 1961 to produce high quality seed potatoes for distribution to Korean farmers. The present program for production of certified seed of Namjak (Irish Cobbler), the only variety recommended for spring plantings, is outlined. In 1976, approximately 10,000 MT of certified grade Namjak seed was produced by members of two Seed Producers Cooperatives in the Daekwanryeong area for distribution by the Office of Seed Production and Distribution (OSPD). The seed was inspected and certified by officers of the National Agricultural Products Inspection Office (NAPIO). Although the quality of the certified seed is far superior to that used by many farmers, the supply planted less than 1/5 of the 1977 potato crop. Certified seed of Shimabara, the variety recommended for autumn plantings, is not produced in Korea. The yield response of virus infected seed to improved cultural practices is poor. Therefore, an increase in potato acreage and yields appears to be possible only if more good quality seed is used by Korean farmers. A two or three fold increase in seed supply would be desirable. The volume of seed could be increased by expanding the production area and by improving yield in seed fields. More land is available in the alpine area and good seed potatoes could be grown in other parts of Korea. Planting better quality seeds and using better cultural pracitces would improve seed yields. Several techniques could be used to improve the quality of elite seed produced at AES. Changes in seed potato certification program should be made so that healthy seed stocks of new varieties can be released rapidly.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.213-217
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• 1999

Seed coating and pelleting techniques have been used in many crops to improve the germination vigor of tiny and light seeds. Cultivated Chinese-foxglove (Rehmannia glutlnosa) has been infected by various types of virus derived from vagetative propagation of rootstock. Seed characteristics and alginate-coated seed germination rate have been investigated to get basic information for healthy seedling production through seed propagation. Chinese-foxglove showed different numbers of seeds per pod from 61 in Seocheon local to 207 in Jiwhang 1 and 1,000grain weight also varied from 70mg of Seocheon local to 130mg of Jiwhang 1. Seeds of Chinese-foxglove has dormancy because that seed collected last year more stimulated than that of this year at germination test. Optimum alginate concentration for pellected seeds germination was 2%.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.83-86
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• 1997

To produce and supply the healthy potato, basic seed potatoes were produced by stem cutting, microtuberization and hydroponic culture. The total number of tubers and the total tuber weight per $\textrm{m}^2$ of potato were more in hydroponic culture as each products were 1, 152 and 4, 492g than in the stem cutting (75 and 4, 136g) or microtuberization (1, 080 and 1, 080g) using petridishes. The total yield per 10a in the field was propagated highly stem cutting > propagated microtubers > hydroponics > microtubers. The number of tubers per 10a produced by hydroponics (33, 064) was higher than any other methods. This indicated the hydroponic culture can be used in the multiplication of basic seed potatoes.