• Research in Plant Disease
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• v.21 no.1
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• pp.20-23
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• 2015

A sequential planting method was developed to screen rice plants with durable resistance against rice blast in a short time, and applied for several years in Korean rice breeding program. In this study, we showed the advantages of a sequential planting method compared to other pathogenicity tests. The correlation analysis among three pathogenicity tests and other factors demonstrated that durable resistance depended on the average of diseased leaf area and the number of compatible pathogens. Significant correlations were found in the nursery test but not in the field test result. In addition, we traced changes in the pathogen population during sequential planting stages through re-isolation of the pathogen. The portion of compatible pathogens was increased during sequential planting. Through this study, we provide an effective sequential planting method and direction of durable resistance in a breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.226-231
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• 2010

The objective of this experiment was determined to investigate the effect of the planting ratio of Male Sterility (MS) to Restorer Line (RL) and harvesting time on fatty acid compositions under $F_1$ seed production of Brassica napus L. For rapeseed seed production, two experiments were conducted in the open fields. One experiment studied planting ratios of MS to RL (4:2, 10:2, or 10:1) were planted and investigated fatty acid composition at 40, 45, 50, 55, and 60 days after flowering, the other $F_2$ seeds were analyzed on fatty acid compositions of harvested seeds at five sequential stages. The results showed that fatty acid compositions of developing seeds were influenced by MS:RL planting ratios and $F_2$ hybrid treatments and contaminated level of fatty acid compositions, erucic acid, were unaffected by planting ratio of MS to RL. Fatty acid compositions such as palmitic acid (C16:0), stearic acid (C18:0) and linoleic acid (C18:2) contents decreased during seed maturation period in $1^{st}$ and $2^{nd}$ experiments. In contrast, oleic acid (C18:1) content relatively increased up to 55days after flowering. At day 60 after flowering, oleic acid content was unaffected by MS:RL planting ratios and $F_2$ seeds treatments. Aspects of related gene expression of fatty acid synthesis such as SAD, FAD1 and FAD2 were followed exactly to changes of fatty acid composition during seed maturation. These results suggest that MS ratio may be enlarged and RL may be reduced, indicating this ratio will be useful for rape seed production.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.1
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• pp.31-37
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• 1988

This study, based on the monthly rainfall data, was carried out to determine the agricultural drought index which enables to describe the regional and seasonal drought characteristics of rice cropping system in Korea. The results obtained were summarized as follows ; 1.A new agricultural drought index (ADI) was evaluated seasonally according to the product of drought intensity and duration. This ADI is proposed as standard design criterion for irrigation planning. 2.The relationship between agricultural drought index and return periods was figured out. These diagrams could be used to estimate the seasonal drought severity of a certain year and to select design year corresponding to the specific drought frequency. 3.The regional drought characteristics were classified and those are useful to determine proper rice varieties and planting time and make drought counterplans. 4.Spring drought occurred once in 3 or 4 years and in a regional respect, rather frequently occurred in Seoul and Daegu areas than in Busan, Daejeon, Kwangju and Chuncheon areas. Summer drought occurred once in 5 years in Daegu and Busan areas and once in 7 or 8 years in other areas. 5.Sequential drought which gave severe drought damage of rice production occurred once in 20 years in Daegu area and in 10 years in Kwangju area.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.394-400
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• 2008

Blast resistance of one hundred and thirty-one rice cultivars bred in Korea was tested with thirty Korean isolates and twenty-two Philippines isolates using three screening methods. In the blast nursery conducted in Korea and in the Philippines, average disease index of rice cultivars were 4.6 and 2.2, respectively. Seventy-nine cultivars showed different resistance reaction in Korea and in the Philippines, and 19 cultivars showed the same resistant reaction in two locations. In the seedling test, Korean blast isolates displayed different levels of virulence. 93-093, a Korean isolate, was compatible with 90 cultivars whereas 97-057 showed a compatible reaction with 13 cultivars. Twenty-three cultivars showed high level of resistance against Korean and Philippines isolates but Chucheongbyeo, Heugnambyeo, and Manmibyeo showed susceptible reaction to all blast isolates. Through the sequential planting test in Korea and in the Philippines, Palgongbyeo and Seomjinbyeo displayed durable resistance, and Nagdongbyeo and Gihobyeo showed high level of disease infection over the planting time. These results indicate that blast isolates collected in two countries have different genetic background and number of compatible isolates should be considered in definition the durability of rice cultivar to rice blast.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.620-624
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• 2011

'Hwaweon 4' was developed from a cross between the African upland cultivar, 'Moroberekan' and 'Ilpumbyeo' based on marker-aided backcross selection. The recurrent parent 'Ilpumbyeo' is a high grain quality cultivar with medium to late maturity. 'Hwaweon 4' is nearly isogenic to 'Ilpumbyeo' except a small Moroberekan introgressed segment on chromosome 4 harboring the resistance gene for blast. The preliminary and replicated yield trial was conducted at Chungnam National University in 2006 and 2007. The local adaptability test was carried out by the National Seed Management Office (NSMO) from 2008 to 2009. This cultivar was registered to NSMO with a cultivar designated as 'Hwaweon 4'. This cultivar averaged 76 cm in culm length and has medium growth duration. Milled rice of 'Hwaweon 4' is translucent and the grain quality traits are comparable to those of the recurrent parent. It has low protein content. The yield potential of 'Hwaweon 4' in grain was about 6.31 MT/ha at the ordinary fertilizer level for two years. This variety showed highly resistance reaction at the blast nursery test at four locations and also at the sequential planting method. This resistance is due to the resistance gene designated as Pi45(t) on chromosome 4 introgressed from the donor parent, 'Moroberekan'. The Pi45(t) gene would be useful inenhancing resistance to blast in rice breeding program.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.4
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• pp.95-112
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• 2013

Jangchungdan Park is now perceived as a mere park at the foot of Namsan mountain, but originally it was created to commemorate soldiers of Korean Empire on a site which name was Namsoyeong(南小營) during Joseon Dynasty. During the period of Japanese colonial rule, it was transformed into a park due to the rapidly changing circumstances, so the components expressing the validity of the colonial rule were introduced into the park. This paper examines the time sequential changes of Jangchungdan Park during the period of Japanese colonial rule, and the conclusions can be summarized as given below. Firstly, the park originally was a space to commemorate the soldiers who fought for the Korean Empire. It was built on formerly restricted area at the foot of Namsan Mountain in 1900, and it was arranged putting the ceremonial shrine Dansa (壇祠) as a central building and the annexes in the surroundings of it. The memorial ceremonies were held regularly in spring and autumn until 1909. Secondly, it became a city park for citizens of Gyeongseong-bu(the name of Seoul under the Japanese colonial rule). The authorities of Gyeongseong-bu reorganized Jangchungdan as a park in 1919, prohibited the performance of memorial ceremonies, and the existing buildings except the ceremonial shrine Dansa began to be used as park management facilities. Resting areas and amenities were supplemented for the usage of people from various backgrounds, and the large scale planting of cherry trees made the park a famous place to enjoy cherry-blossoms and other flowers in spring. Thirdly, it was reconstructed as a space to honor the influential personalities of Japanese colonial system. In 1932, Bankmun temple (博文寺) to commemorate Ito Hirobumi was constructed at a location that made it possible for a number of people to overlook Jangchungdan area. During that time, the buildings of traditional Joseon architecture were removed and reconstructed to serve as annexes to Bankmun temple. Due to the strategy to make Jangchungdan park a tourist attraction, Bankmun temple was included into the Gyeongseong sightseeing course, since the wide panorama of Jangchungdan Park and the whole city of Gyeongseong was opening from the temple. Various different components were introduced into Jangchungdan Park due to the rapidly changing circumstances; therefore the nature of the park was either altered or reproduced. Hopefully, the park rearrangement works will be executed paying respects to the memories of the past hereafter.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.42-49
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• 2011

QTL analysis for blast resistance was carried out using 140 $BC_3F_3$ lines derived from a cross between Ilpum as a recurrent parent and Moroberekan as a donor parent. 140 $BC_3F_3$ lines with the parents were inoculated with nine blast isolates. To identify QTLs for resistance to nine blast isolates, 134 SSR markers showing polymorphisms between the parents were genotyped for the 140 $BC_3F_3$ lines. A total of 17 resistance QTLs to nine isolates were detected on chromosomes 2, 3, 4, 6, 7, 9 and 10. The phenotypic variance explained by each QTL ranged from 8.2% to 26.4%. The Moroberekan alleles contributed the positive effect at these 17 QTL loci. In a previous study, the QTL, Pi45(t) for durable resistance to blast was identified using a sequential planting method. To know the relationship between Pi45(t) and the isolate-specific resistance gene, an $F_2$ population was developed from a cross between Ilpum and an introgression line harboring Pi45(t). $F_3$ lines segregating for the Pi45(t) were inoculated to three isolates. $F_3$ lines from the $F_2$ plants with the Moroberekan segment at the target region showed resistance to two isolates. This result seems to indicate that the Pi45(t) and the isolate-specific resistance gene are tightly linked or the resistance is controlled by the same gene(s). The markers linked to genes controlling blast resistance would be useful in developing blast resistance lines in the breeding program.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.408-413
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• 2008

Rice blast resistance is considered one of the most important traits in rice breeding and the disease, caused by Magnaporthe grisea Barr, has brought significant crop losses annually. Moreover, breakdown of resistance normally occurs in two to five years after cultivar release, thus a more durable resistance is needed for better control of this disease. We developed a new variety, Keumo3, which showed strong resistance to leaf blast. It was tested in 2003 to 2007 at fourteen blast nursery sites covering entire rice-growing regions of South Korea. It showed resistance reactions in 12 regions and moderate in 2 regions without showing susceptible reactions. Durability test by sequential planting method indicated that this variety had better resistance. Results showed that Keumo3 was incompatible against 19 blast isolates with the exception of KI101 by artificial inoculation. To understand the genetic control of blast resistance in rice cultivar Keumo3 and facilitate its utilization, recombinant inbred lines (RIL) consisting of 290 F5 lines derived from Akidagomachi/Keumo3 were analyzed and genotyped with Pizt InDel marker zt56591. The recombination value between the marker allele of zt56591 and bioassay data of blast nursery test was 1.1%. These results indicated that MAS can be applied in selecting breeding populations for blast resistance using zt56591 as DNA marker.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.520-524
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• 2009

A newly developed rice variety "Pungmi 1" is a japonica rice(Oryza sativa L.) with high grain quality and multi-resistant to diseases. It was developed by the rice breeding team of Yeongnam Agricultural Research Institute (YARI), RDA. in 2004. This variety derived from a cross between "YR13616Acp 1", having short culm and multi-resistance to biotic stresses and "Milyang 122" with good grain quality. It has short stature of 73cm in culm length and mid-early flowering date of Aug. 13. This variety is moderately resistant to leaf blast showing durable resistance of lower 10% diseased leaf araea in sequential planting meothod. Milled rice kernel of "Pungmi 1" is translucent, clear in chalkness and good at eating quality in panel test. Milling recovery and head rice ratios were comparable to Milyang 122, while it has low protein content. The milled rice yield potential of "Pungmi 1" is about 5.59 MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to Yeongnam inland plains and southern coastal areas of Yeongnam province at ordinary transplanting as well as after barly cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.388-397
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• 1985

Forage productivity and sequential changes in forage quality of four rye and two triticale varieties were studied. All the observed characteristics were similar among rye or triticale varieties, but they were different between rye and triticale varieties. Early growth of rye was better compared to triticale varieties, but at heading stage yield in dry weight, digestible dry matter and percent dry matter of triticale were higher compared to rye varieties. Heading stage of rye was earlier than that of triticale by 11 - 14 days. Triticale had longer and broader leaf blades and a higher leaf blade/total dry weight ratio compared to rye. Protein content decreased as plant growth advanced and it was higher in rye before heading, but it was similar after heading compared to triticale. Cellulose and lignin contents of rye increased through 20 days after heading. However, in triticale cellulose increased until heading stage and it levelled off, but lignin content increased rapidly after heading. Among the crude fibers, only acid detergent fibers(ADF) was negatively correlated with in vitro dry matter digestibility(IVDMD) in both rye and triticale. IVDMD of rye decreased rapidly after heading, but it was maintained as high as heading stage up to 15 days after heading in triticale. Protein content and IVDMD in leaf blades were higher than those of culm + leaf sheath, hemicellulose was similar, and cellulose, lignin, and ADF in leaf blades were lower compared to culm + leaf sheath. In the early and middle part of April rye was superior to triticale as a soiling crop because of a better plant growth of rye under the low temperature conditions, but in the later part of April and early part of May triticale was superior to rye because of a rapid decreased in IVDMD of rye after heading and a late maturing characteristics of triticale. Planting both rye and triticale could prolong the utilization period of the soiling crops and increase in yield with better quality compared to a single crop of rye or triticale.