• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.6
• /
• pp.639-643
• /
• 2002

Water quality, bacterial phase and fish growth rate were analyzed in the process of artificial seed production of flounder (Paralichtys oliraceus) larvae to investigate the water quality in rearing tank using Ultra Filtration System (UES). Sand Filtration System (SFS) and Ultra Filtration System (Ins) were set up in the experimental group. For the analysis of water quality, pH, salinity, DO, SS, COD, $NH_{4}^{+},\;NO_{2}^{-},\;NO^-,\;DIN$ (dissolved inorganic nitrogen) and DU (dissolved inorganic phosphate) were measured. There was no data difference between SFS group and UES group in most analysis items, but the UEs group showed low salinity and low 55 values, such that salinity was $33.5\%_{\circ}$ in SES group and $30.2\%_{\circ}$ in WS group and 55 was 15.5 mL/L in SES group and 7.0 mL/L for UPS group. For changes in bacterial phase and TBC (Total Bacterial Counts), in SES group, 6$\times$10^{5}CFU/mL in seawater decreased to the ratio of about 116, and TBC, Genus Vibrio and bacteria in the Genus Acinetobacter and Genus Micrococcus sharply increased after nine days, while stable bacterial phase was maintained low in UES group during the experiment except for Genus Ajteromonas. In the growth of the larvae, fish length was 17.0 mm (SGR 14.0) in the SES group and 18.8 mm (SGR 14.3) in the UFS group. It is concluded that when water is supplied for artificial seed production with WS, stabilization of water quality condition and inhibition of bacterial multiplication are possible. When production environment becomes stable, stable growth of fish becomes possible by reduction of environmental stress.

• FLOWER RESEARCH JOURNAL
• /
• v.16 no.4
• /
• pp.299-303
• /
• 2008

An Oriental lily cultivar 'Pacific Wave' was released in 2007 at National Institute of Horticultural and Herbal Science, Rural Development Administration (RDA), Suwon, Korea. The crossing was made in 1999 between Oriental lily 'Simplon', an outward-facing and white colored cultivar, and 'Spinoza', pink colored cultivar. The first selection was done in 2003 with a line of 'O-03-16'. Multiplication and bulb growth, and performance test was conducted from 2004 to 2006. This selection was later on given as 'Pacific Wave' in 2007 at NHRI. Flowering time of 'Pacific Wave' in plastics house culture is mid June and grows average 115 cm. Flowers are upward-facing with 20.1 cm in diameter and white with yellow centered (RHS W155C + Y9A). Mean petal length and width is 12.2 cm and 4.2 cm, respectively. Leaves are 12.3 cm long, 2.9 cm wide. The throat color is green. It shows gray and purple stigma, and red brown pollen. The weight and size of bulb is 82.5 g and 19.6 cm, respectively. Year-round flowering can be by storing the bulb under -1 to $-2^{\circ}C$ conditions. It is necessary to add calcium to the fertilizer or remove side scales to prevent leaf scorch. It is needed to control Botrytis disease in summer wet season.

• Korean Journal of Plant Resources
• /
• v.20 no.5
• /
• pp.389-397
• /
• 2007

Using the active-increment of Tos17 copies in the genome of Oryza sativa L., there were many studies about induction and selection of new mutants. This study mainly focuses on the induction for retrotransposon(Tos17) activity in the callus of Ilpumbyeo(Oryza sativa L.) according to varied culture period and condition. The objectives of this study are obtaining various mutants($M_1$) through plant regeneration, identification of the mutation relation with Tos17, and subsequent phenotyping of the mutants($M_2,\;M_3$). A total of 371 $M_1$ mutants was obtained. The degree of Tos17 activity obtained regeneration plants with each different culture period was evaluated by Southern blot analysis. The result showed that control Ilpumbyeo rice has 5 numbers of copies and the band numbers obtained 7, 8, 9.5, 12, 6, 13.5, 17.5 from culture period of 1, 2, 3, 5, 6, 7, 8 month, respectively. In this study, the result showed that most effectual culture period for activity of Tos17 in Ilpumbyeo rice is 5 month. Hereafter, collections and analysis of various recombination plants will act on an important factor in multiplication and preservation of $M_2$ and $M_3$ generation. And an urgent and important subject is a development of screening method for selection of diverse mutants.

• Journal of Sericultural and Entomological Science
• /
• v.50 no.2
• /
• pp.63-70
• /
• 2012

This study was conducted to investigated the distribution, ecological character and life cycle of Black Soldier Fly(BSF), Hermetia illucens, to determine effects of BSF on composing ability to the livestock feces. The distribution of BSF was defined in all parts of the country in Korea. Its main habitat was found to be areas near cattle sheds, feces sheds, living waste dump grounds, and food waste dump grounds. Excellent species of the bio-conversion using the livestock feces were selected out of two kinds of solider flies(Hermetia illucens and Ptecticus tenebrifer). And effects of BSF on composing ability to the livestock feces were pig feces 0.5 g, cattle feces 0.43 g and chicken feces 0.3 g per a larvae of BSF. In the examination of the ability of BSF to decompose food waste, volume of the livestock feces decreased by weight pig feces 77, cattle feces 83.62 and chicken feces 80%. Observed characteristics of BSF larvae and pupae stage were by developmental stage may be summarized as follows: size and length of larvae and pupae of BSF were higher than in pig feces and mixed sawdust treatments. In order to develop artificial indoor rearing techniques, The pupation and emergence rate were not visible the difference but important factor of the mating and egg-laying was a sun light. And it was visible the difference in mating ratio. Mating rate of H. illucens by seasonal change was the highest from May to July. Mating mostly occurred between 10 : 00 and 12 : 00 during which light intensity is high. As the egg-laying medium for artificial egg collection, calf feed and food waste were most effective. The ratio of egg-laying medium is waste food : sawdust(1 : 1) in volume. For egg-laying materials, flower foam and wood with holes were used; holes sized 3 ~ 5 mm in diameter, 7 ~ 10 mm in depth were most preferred for egg-laying.

• Korean Journal of Plant Resources
• /
• v.32 no.1
• /
• pp.53-62
• /
• 2019

The purpose of this study was to establish the in vitro propagation system by shoot tip culture of six Hosta species native to Korea (Hosta capitata (Koidz.) Nakai, H. clausa Nakai, H. jonesii M.G.Chung, H. minor (Baker) Nakai, H. venusta F.Maek., and H. yingeri S.B.Jones) for mass proliferation and a new cultivar development. The shoot tips of each Hosta species were cultured on MS medium containing eight combinations of 0.5, 1.0, 2.0, 4.0 mg/L BA with 0.1 mg/L NAA, 0.1, 0.5, 1.0, 2.0 mg/L TDZ with 0.1 mg/L NAA, and without any PGRs (control). They were investigated on callus, somatic embryo, crown bud, differentiation and growth of shoot and root, total fresh weight after 8 weeks of culture. In all six Hosta species, callus and somatic embryo induction rate and multiple shooting rate of the PGRs treatment group were higher than that of the control group. The highest number of differentiated shoots were obtained on medium supplemented with 2.0 ㎎/L TDZ in H. capitata (5.4), 1.0 mg/L TDZ in H. clausa and H. jonesii (3.3 and 5.8, respectively), 0.5 mg/L BA in H. minor (11.1), 1.0 mg/L BA and 0.1 mg/L TDZ in H. venusta (8.1), and 0.5 mg/L TDZ in H. yingeri (9.8). In somatic embryo formation, the PGRs treatment group of H. jonesii and H. yingeri were more effective than the control group, and the effects were relatively less in H. capitata, H. clausa Nakai, H. minor, H. venusta. Crown bud formation of four Hosta species (H.capitata, H. clausa, H. jonesiig, and H. yingeri) were also higher in the PGRs treatment group than in the control group. Crown bud formation of four Hosta species (H.capitata, H. clausa, H. jonesiig, and H. yingeri) were also higher in the PGRs treatment group than in the control group. H. clausa showed no significant effect on callus and shoot differentiation regardless of the type and concentration of cytokinin, but slightly increased in formation of crown bud in TDZ.

• Research in Plant Disease
• /
• v.26 no.4
• /
• pp.272-278
• /
• 2020

The severe lettuce damage caused by Paratylenchus projectus was first reported in 2019 in Korea. To find high-value rotation crops for the control of P. projectus, nine vegetables, Brassica juncea (leaf mustard), B. rapa subsp. nipposinica (kyona), B. oleracea var. italica (broccoli), B. rapa subsp. chinensis (bok choy), B. oleracea var. viridis (kale), B. oleracea var. gongylodes (kohlrabi), Cichorium endivia (endive), C. intybus (chicory), Ipomoea aquatica (morning glory) were planted in d-10-cm clay pots in greenhouse. The growth of vegetables was compared between inoculated with 3,000 P. projectus per 100 ㎤ of soil and non-inoculated. Treatments were replicated 10 times. After 100 days, the reduction of fresh top weight was 30.4% in C. intybus, 35.1% in I. aquatica, 36.9% in B. oleracea var. acephala, 40.5% in C. endivia, 42.1% in B. rapa, 47.5% in B. rapa subsp. nipposinica, 50.4% in B. oleracea var. gonglodes, 56.3% in B. oleracea var. italica, and 66.0% in B. juncea. Nematode multiplication rates (Pf/Pi) were lower in I. aquatica (0.64) and C. endivia (1.1), but higher in B. oleracea var. gongylodes (2.54). Considering these results, I. aquatica is suitable for the rotation crop with lettuce until better rotation crops developed.

• Journal of Food Hygiene and Safety
• /
• v.36 no.6
• /
• pp.481-487
• /
• 2021

The purpose of this study was to provide safety management information by analyzing the survival and growth-related properties of foodborne pathogens from Romaine lettuce. After cultivating E. coli O157:H7 for 72 h on Romain lettuce via spray inoculation, the bacteria population increased by 2.0 log CFU/g from the initial population, confirming the possibility of survival and multiplication of the pathogen thereon. The study also revealed that there is no significant difference in the cultivation of E.coli O157:H7 after 72 h from inoculation on damaged and undamaged lettuce leaves. As a result of investigating distribution of E.coli O157:H7 on damaged lettuce leaves, it was found that the bacteria is unlikely to adhere on the smooth surface of undamaged leaves and, thus, results in a low population density, whereas the bacteria cluster on the rough surface of damaged leaves and easily enter through the damaged tissues. Furthermore, after 24 h of cultivation of the pathogenic microbe in the extract with concentrations of 10-100%, utilization of the lettuce extract by the pathogen was found to be 8.9 log CFU/mL E. coli O157:H7, 8.6 log CFU/mL L. monocytogenes, and 8.8 log CFU/mL P. carotovorum. The increase in the population of both the pathogenic microbe and foodborne pathogen reached over 4 log CFU/mL, implying the microbe can utilize the lettuce extract as a source of nutrition. Compared to the initial inoculation concentration in 0.1% lettuce extract, the final concentration has increased up to 2.7 log CFU/mL E. coli O157:H7, 1.3 log CFU/mL L. monocytogenes, and 2.9 log CFU/mL P. carotovorum. Accordingly, the study confirms that the minimal growth concentration of the pathogenic microbe is lower than 0.1% and that the pathogen possibly survive and multiply inside the lettuce leaves given the lettuce extract with concentration of 0.1% is consistently supplied through the damaged tissues.

• Korean Journal of Poultry Science
• /
• v.50 no.1
• /
• pp.41-50
• /
• 2023

Over the last decade, avian influenza (AI) has been considered an emerging disease that would become the next pandemic, particularly in countries like South Korea, with continuous animal outbreaks. In this situation, risk assessment is highly needed to prevent and prepare for human infection with AI. Thus, we developed the risk assessment matrix for a high-risk area of human infection with AI in South Korea based on the notion that risk is the multiplication of hazards with vulnerability. This matrix consisted of highly pathogenic avian influenza (HPAI) in poultry farms and the number of poultry-associated production facilities assumed as hazards of avian influenza and vulnerability, respectively. The average number of HPAI in poultry farms at the 229-municipal level as the hazard axis of the matrix was predicted using a negative binomial regression with nationwide outbreaks data from 2003 to 2018. The two components of the matrix were classified into five groups using the K-means clustering algorithm and multiplied, consequently producing the area-specific risk level of human infection. As a result, Naju-si, Jeongeup-si, and Namwon-si were categorized as high-risk areas for human infection with AI. These findings would contribute to designing the policies for human infection to minimize socio-economic damages.

• Proceedings of the Korean Society of Tobacco Science Conference
• /
• 1997.10a
• /
• pp.134-152
• /
• 1997

Plant viruses of tobacco including tobacco mosaic virus (TMV) and potato virus Y (PVY) cause severe economic losses in leaf-tobacco production. Cultural practices do not provide sufficient control against the viruses. Use of valuable resistant cultivars is most recommendable for the control of the viruses. However, conventional breeding programs are not always proper for the development of virus-resistant plants mostly owing to the frequent lack of genetic sources and introduction of their unwanted properties. Therefore, we tried to develop virus-resistant tobacco plants by transforming commercial tobacco cultivars, NC 82 and Burley 21, with coat protein (CP) or replicase (Nlb) genes of TMV and PVY necrosis strain (PVY-VN) with or without untranslated region (UTR) and with or without mutation. Each cDNA was cloned and inserted in plant expression vectors with 1 or 2 CaMV 35S promotors, and introduced into tobacco leaf tissues by Agrobacterium tumefaciens LBA 4404. Plants were regenerated in kanamycin-containing MS media. Regenerated plants were tested for resistance to TMV and PVY In these studies, we could obtain a TMV-resistant transgenic line transformed with TMV CP and 6 genetic lines with PVY-VN cDNAs out of 8 CP and replicase genes. In this presentation, resistance rates, verification of gene introduction in resistant plants, stability of resistance through generations, characteristics of viral multiplication and translocation in resistant plants, and resistance responses relative to inoculum potential and to various PVY strains will be shown. Yield and quality of leaf tobacco of a promising resistant tobacco line will be presented.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.18
• /
• pp.54-87
• /
• 1975

The effects of various weather factors on yield components of rice, year variation of yield components within regions, and regional differences of yield components within year were investigated at three Crop Experiment Stations O.R.D., Suweon, Iri, Milyang, and at nine provincial Offices of Rural Development for eight years from 1966 to 1973 for the purpose of providing information required in improving cultural practices and predicting the yield level of rice. The experimental results analyzed by standard partial regression analysis are summarized as follows: 1. When rice was grown in ordinary seasonal culture the number of panicles greatly affected rice yield compared to other yield components. However, when rice was seeded in ordinary season and transplanted late, and transplanted in ordinary season in the northern area the ratio of ripening was closely related to the rice yield. 2. The number of panicles showed the greatest year variation when the Jinheung variety was grown in the northern area. The ripening ratio or 1, 000 grain weight also greatly varied due to years. However, the number of spikelets per unit area showed the greatest effects on yield of the Tongil variety. 2. Regional variation of yield components was classified into five groups; 1) Vegetation dependable type (V), 2) Partial vegetation dependable type (P), 3) Medium type (M), 4) Partial ripening dependable type (P.R), and 5) Ripening dependable type (R). In general, the number of kernel of rice in the southern area showed the greatest partial regression coefficient among yield components. However, in the mid-northern part of country the ripening ratio was one of the component!; affecting rice yield most. 4. A multivariate equation was obtained for both normal planting and late planting by log-transforming from the multiplication of each component of four yield components to additive fashion. It revealed that a more accurate yield could be estimated from the above equation in both cases of ordinary seasonal culture and late transplanting. 5. A highly positive correlation coefficient was obtained between the number of tillers from 20 days after transplanting and the number of panicles at each(tillering) stage 20 days after transplanting in normal planting and late planting methods. 6. A close relationship was found between the number of panicles and weather factors 21 to 30 days, after transplanting. 7. The average temperature 31 to 40 days after transplanting was greatly responsible for the maximum number of tillers while the number of duration of sunshine hours per day 11 to 30 days after transplantation was responsible for that character. The effect of water temperature was negligible. 8. No reasonable prediction for number of panicles was calculated from using either number of tillers or climatic factors. The number of panicles could early be estimated formulating a multiple equation using number of tillers 20 days after transplantation and maximum temperature, temperature range and duration of sunshine for the period of 20 days from 20 to 40 days after transplantation. 9. The effects of maximum temperature and day length 25 to 34 days before heading, on kernel number per panicle, were great in the mid-northern area. However, the minimum temperature and day length greatly affected the kernel number per panicle in the southern area. The maximum temperature had a negative relationship with the kernel number per panicle in the southern area. 10. The maximum temperature was highly responsible for an increased ripening ratio. On the other hand, the minimum temperature at pre-heading and early ripening stages showed an adverse effect on ripening ratio. 11. The 1, 000 grain weight was greatly affected by the maximum temperature during pre- or mid-ripening stage and was negatively associated with the minimum temperature over the entire ripening period.