• Korean Journal Plant Pathology
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• v.1 no.2
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• pp.109-114
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• 1985

The experiments were conducted to clarify the influence of transplanting date on the occurrence of rice virus in field condition of 1984. The rate of RBSDV (rice black-slreaked dwarf virus) viruliferous vector, smaller brown planthopper (Laodelphax striatellus Fallen), was shown to be $13.6\%$ at the 2nd adult and that of rice stripe virus (RSV) viruliferous was $6.7\%$ at the 2nd adult. The vector in the field was begun to come from May 29, the maximum densities were 19.6 insects per hill on June 13 in cultivar Chucheongbyeo, 19.3 in Nagdongbyeo, 7.4 in Cheongcheongbyeo and 4.9 in Samgangoyes. The number of vectors per hill was inclined to increase by early transplanting. Although the infection of rice virus in nursery bed was not recognized until May 30 transplanting, the nursery infection could be seen from June 10 transplanting. The highest rate of nursery infection with RSV was $4.1\%$ at June 10 transplanting plot, and that of RBSDV was $14.2\%$at June 20 trans planting plot. The infection of rice virus in paddy field was the highest at May 20 transplanting plot, the lowest at July 10 plot. The earlier transplanting, the more severe occurrence of rice viruses. Occurrence of infected plants with RBSDV was shown to increase more rapidly at May 20 and May 30 planting plot than May 10 plots. However, the occurrence of infected plant with RSV was more rapid at May 10 transplanting plot than May 20 and 30.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.1
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• pp.74-80
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• 1988

Seasonal population changes in Laodelphax striatellus Fallen (small brown planthopper), percentage of rice black-streaked dwarf virus (RBSDV) viruliferous L. striatellus, and RBSDV infection of 11 corn hybrids were observed at various locations and years. The population size of L. striatellus was relatively small in the middle parts of Korea, but it was much greater in the southern areas. The population size of the first generation of adult L. striatellus emerged from late April to early May was similar or smaller compared with that of the second generation emerged in middle June in the middle parts of Korea. However, in the southern areas the population size of second generation was much greater than the first generation. The percentage of RBSDV viruliferous L. striatellus differed depending on the years, locations, and testing methods. The percentage of viruliferous vector was highest in southern plain areas and it tended to decrease with distance from the areas. The percentage of viruliferous vectors tested by enzyme-linked immunosorbent assay was higher than that tested by rice seedling test. The RBSDV infection rate of corn hybrids was highest at Daegu and ranged from 9 to 39% probably due to both a higher L. striatellus population and a higher percentage of viruliferous vectors. However, it was significantly lower in other areas and ranged from 0 to 13%.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.83-83
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• 2017

The National Agrobiodiversity Center (NAS, RDA, Republic of Korea) has continually collected new valuable genetic resources. In this study, we regenerated conserved kidney bean (Phaseolus vulgaris L.) germplasm which couldn't be available because of seed quantity and quality, and we also surveyed their morphological characters for the sustainable utilization. A total of 431 kidney bean accessions were regenerated and 18 morphological traits were surveyed according to the characterization guideline of RDA Genebank. Among the surveyed traits, flowering time ranged from May 23 to September 4 and 73.8% of tested accessions were mainly flowering in June. The maturity time ranged from July 1 to October 15 and main flowering time was July (91.4%). For plant type, 270 accs (62.6%) were climbing type followed by medium type of 86 accs (20.0%) and dwarf type of 65 accs (15.1%). The seed coat colors were various; yellow (34.6%), white (22.3%), brown (17.9%), red (10.7%), black (5.8%), violet (11%), pink (1.4%), navy (0.9%). Principal component analysis indicated that five principal components (PCs) with Eigen values >1 accounted for more than 65.8% variability. The first PC was more related to growth habits such as growth type, flowering time, and plant type. The second and third PCs showed higher values of the pigment characters such as seed coat color, flower color, and pod color. In fourth and fifty PCs, there were the higher positive values of the pod shapes. Our results provided insight into the characteristics kidney beans, thus the utilization basis of kidney beans might be elevated for bio-industry.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.44.1-44.1
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• 2017

The single lens event OGLE-2015-BLG-1482 has been simultaneously observed from two ground-based surveys and from Spitzer. The Spitzer data exhibit finite-source effects due to the passage of the lens close to or directly over the surface of the source star as seen from Spitzer. Thanks to measurements of the microns parallax and the finite-source effect, we find that the lens of OGLE-2015-BLG-1482 is a very low-mass star with the mass $0.10{\pm}0.02M{\odot}$ or a brown dwarf with the mass $55{\pm}9MJ$, which are respectively located at $DLS=0.80{\pm}0.19kpc$ and $DLS=0.54{\pm}0.08kpc$, and thus it is the first isolated low-mass microlens that has been located in the Galactic bulge. The degeneracy between the two solutions is severe. The fundamental reason for the degeneracy is that the finite-source effect is seen only in a single data point from Spitzer and this single data point gives rise to two ${\rho}$ solutions.

• Journal of The Korean Astronomical Society
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• v.51 no.6
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• pp.197-206
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• 2018

We present the analysis of KMT-2016-BLG-0212, a low flux-variation ($I_{flux-var}{\sim}20mag$) microlensing event, which is in a high-cadence (${\Gamma}=4hr^{-1}$) field of the three-telescope Korea Microlensing Telescope Network (KMTNet) survey. The event shows a short anomaly that is incompletely covered due to the brief visibility intervals that characterize the early microlensing season when the anomaly occurred. We show that the data are consistent with two classes of solutions, characterized respectively by low-mass brown-dwarf (q = 0.037) and sub-Neptune (q < $10^{-4}$) companions. Future high-resolution imaging should easily distinguish between these solutions.

• Korean Journal of Plant Resources
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• v.24 no.1
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• pp.17-22
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• 2011

This study was for developing leaf chlorophyll mutant cultivars of Cymbidium goeringii by ethyl-methanesulfonate(EMS) treatment. Chlorophyll mutant rhizomes were easily produced by 0.2% EMS treatment in this genus. Among the mutants, they became dark brown about 50% of the rhizomes. When the dark-brown rhizomes were cultured in a solidified MS medium, new rhizomes were formed from part of the old ones. Chlorophyll mutant rhizomes were obtained from subcultured meristem tissues of newly-formed rhizomes. The rhizomes were cut and subcultured for a year and then became mutant plants. As the results, they produced 4 kinds of leaf mutant cultivars; zigzag-striped, comb-striped, net-striped, and dwarf types, indicating that the EMS treatment in the rhizome could produce versatile leaf chlorophyll regulating mutants. These results suggest that our method is useful for developing leaf mutant cultivars of this planta which they are estimated as higher commercial values.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.249-255
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• 1987

To find out the optimum planting date of silage corn in the rice black-streaked dwarf virus (RBSDV) pre-valent area, a resistant hybrid of Jinjuok and a susceptible hybrid of Suweon 19 were planted at the 8 planting dates from April 1 to June 10 at the la-day intervals. Considering escape of RBSDV and silage yield, the optimum planting date seems to be during the April in both hybrids. At the April plantings silage yield of two hybrids ranged from 17 to 23 tons/ha on the dry matter base due to a lower infection rate and higher tolerance to RBSDV and there was no difference in silage yield between two hybrids. At the May plantings yield of ear, stover, and silage, culm length, and digestible dry matter decreased significantly as planting date delayed due to an increase in RBSDV infection rate in both hybrids although performance of a resistant hybrid of Jinjuok was better than a susceptible hybrid of Suweon 19. At the June 10 planting RBSDV infection rate was low and performance of corn was better than that at the May plantings but poorer than that at the April plantings. The peak of small brown planthopper population occurred in late March or early April, middle June, middle July, and early September although it fluctuated a little yearly. Very low small brown planthopper population during the May may attribute to a lower RBSDV infection and high silage yields at the April plantings because the plants grow enough to be tolerant when infected by RBSDV in middle June. However, at the May plantings plants are too young to be tolerant when infected by RBSDV in middle June.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.290-295
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• 2019

This study was carried out to investigate the possibility of establishing a reproductive system for the seed of Pedicularis hallaisanensis, which is in the endangered wild species II class in Korea. The seed of P. hallaisanensis is egg-shaped, and the seed coat is dark brown. The embryo was identified as a dwarf type by the seed section. The seed length was $0.47{\pm}0.07mm$, width $0.16{\pm}0.006mm$, and thickness $0.12{\pm}0.01mm$. The weight of one seed was $0.0003{\pm}0.0001mg$, and 1000 seeds weighed $4.59{\pm}0.02mg$. The degree of seed viability was 75.33% by the tetrazolium (TZ) assay. The highest germination rate of P. hallaisanensis seed was 71% after 4 weeks of storage at $4^{\circ}C$. However, the germination rate tended to decrease gradually over a longer storage period. The germination rates after 6 or 8 weeks of storage at $4^{\circ}C$ were 64% and 60%, respectively. We used two host plants, Artemisia princeps and Dendranthema zawadskii, to determine the effect of host plants on P. hallaisanensis seed germination. The germination of P. hallaisanensis mixed with A. princeps or D. zawadskii started at 53.5 and 62.5 days after sowing, respectively. We did not find any germination 164 days postsowing with both host plants. When A. princeps and D. zawadskii were used as host plants for P. hallaisanensis seed germination, P. hallaisanensis seed germination rates were 45.5% and 19.5%, respectively. The average time to germination was 70.2 days for A. princeps, and 46.8 days for D. zawadskii.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.472-477
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• 2018

"Hyangcheola" is a new japonica rice variety developed as a cross between "Joryeong" and "Seolhyangchal" by the rice breeding team at NICS in 2014. The heading date of "Hyangcheola" is July 28 in the middle plain area, which is 8 days earlier than that of "Hwaseong." "Hyangcheola" has a 76 cm long culm, which is 8 cm shorter than "Hwaseong" and has 86 spikelets per panicle. The viviparous germination rate of "Hyangcheola" was 27.9%. It showed resistance to stripe virus but susceptibility to bacterial blight (K1, K2, and K3 races), dwarf and black streak dwarf viruses and planthoppers. The milled rice of this variety exhibits translucent and medium short grain shape. The protein content of "Hyangcheola" was 8.2%, which was 1.5% higher than that of "Hwaseong." "Hyangcheola" is a rice with a fragrant aroma. The content of iron in 100 g of brown "Hyangcheola" rice was 15.12 mg, which is 3.69 mg higher than that of "Hwaseong," and the zinc content was 32.24 mg, which is 8.75 mg more than that of the comparative variety "Hwaseong." The average milled rice yield of "Hyangcheola" was 4.8 MT/ha at our sites under ordinary cultivation (Registration No. 6807).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.129-133
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• 2007

To breed virus resistant rice variety, developing an efficient screening method is the most important. Two screening methods such as field screening and tray screening method have been used, but the efficiency of the field screening method is too low because of environment factors and the that of the tray screening method is good but screening capability is limited with only $200{\sim}300$ lines per year. To overcome those problems, mass screening method using screen house was developed. Barely as host plant of vector insect was grown in screen house in winter season. Then viruliferous insects are spread in the first spring of the initiation year and sustain them annually. Screening of virus resistance was tested two times in a year, the first screening was from April to June and the second from July to September. The virus infected rate of each susceptible varieties was increased to 92% for RSV and 100% for RDV from the second year. Also, this method can evaluate as many as $1,500{\sim}2,000$ pedigree lines in one time compared with the tray screening method. The result indicates that the mass screening method using screen house, which combines the advantages of the field and tray screening methods, is proven to be more efficient and reliable.