• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.398-410
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• 1982

Summer crops grown in uplands are greatly diversified and show a large variation in difference with year and location in Korea. The principal factor for the variation is weather, in which precipitation and temperature play a leading role and such a weather factors as wind, sun lights also influence production of the summer crops. Since artificial control of weather conditions as a main stress factor for crop production is almost impossible, it must be minimized only by an improvement of cultivation techniques and crop improvement. Precipitation plays a role as one of the most important factor for production of the summer crops and it is considered in two aspects, drought and excess moisture. This country, which belongs to monsoon territory, necessarily encounter one of this stress almost every year, even though the level is different. Therefore, the facilities for both drought and excess moisture are required, but actually it is not easy to complete for them. On this account, crops tolerant to drought, excess moisture and pests should be considered for establishing summer crops. For the districts damaged habitually every season, adequate crops should be cultured and appropriate method of planting, drainage and weed control should be applied diversely. Injuries by temperature is mainly attributed to lower temperature particularly in late fall and early spring, although higher temperature often causes some damages depending upon the kind of crops. Sometimes, lower temperature in summer season playa critical role for yield reduction in the summer crops. However, certain crops are prevented to some extent from this kind of stress by improving varieties tolerant to cold, hot weather or early maturing varieties. As is often the case, control of planting time or harvesting is able to be a good management for escaping the stress. Lodging, plant diseases and pests are considered as a direct or indirect damage due to weather stress, but these are characters able to be overcome by means of crop improvement and also controlled by other suitable methods. In addition, polytical supports capable of improving constitution of agriculture into modern industry is urgently required by programming of data for the damages, establishment of damage forecasting and compensation system.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.129-150
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• 1985

The present investigation was conducted to provide a systematic approach necessary to establish an integrated insect pest management program of barley in Korea. Some ecological surveys on insect pests of barley have been undertaken at the field of Experimental Station, Ky$\check{o}$ngbuk Provincial Office of Rural Development as a fixed point survey area, and at 23 localities for round survey throughout southern and central Korea from 1983 to 1984. Previously known insects injurious to barley in Korea were revised and the population dynamics of 10 dominant harmful species were analyzed according to either 24 localities or 25 cultivars respectively by using several sampling methods of net sweeping, black light traps, yellow water pan traps and visual counting. As the results, a total of 94 species belonging to 77 genera under 32 families are known to be injurious to barley, among them 20 species are newly added here. In the population density level, the dominant species were disclosed as Laodelphax striatellus (43.1 %), Macrosiphum avenae(27.0 %), Rhopalosiphum padi(6.5 %), R. maidis(5.4 %), Psammolettix strialus(2.7 %), Chlorops oryzae(2.2 %), Agromyza albipennis(2.1 %) Phyllotreta nemorum(1.4 %), Chaetoenema cylindrica(1.0 %), Dolycoris baccarum(1.0 %) in order. For the general abundance of major insect pests, it was highest in the cultivar P'aldal whereas lowest in Milyang #22. There were tendencies that Psammotettix striatus, Dolycoris baccarum, Phyllotreta nemorum and Chaetocnema cylindrica represented a maximum increase in the beginning of June, while Chlorops oryzae and Agromyza albipennis showed in the middle of May but aphids were in the end of May. In the dominance of natural enemies, Nabis stenoferus occupied 21.4 % and Propylaea japonica 9.6 %.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.213-219
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• 2009

This study was carried out to establish breeding system for interspecific hybridization of Lilium using spontaneous meiotic polyploidization of $F_1$ OA hybrid and its progenies. Pollen viability and germination of $F_1$ OA interspecific hybrid showed variation by collection time, indicating that pollen grain in June, which was natural blooming season, had better viability and germination ability than in October. 2n-gametes from spontaneous meiotic polyploidization of OA hybrid were crossed with either diploid Asiatic or Oriental hybrid, and subsequent progenies crossed with Asiatic hybrid as female and OA hybrid as male showed the highest efficiency, where 2x-2x A$\times$OA produced 0.64 plants per cross combination, while 2x-2x, O$\times$OA and 2x-2x, OA$\times$A crosses produced 0.42 and 0.4 plant per ovary, and especially no progeny was obtained in 2x-2x, OA$\times$O cross combination. For the subsequent progeny production, a cross between diploid Asiatic hybrid as female and diploid OA hybrid as male was the best ploidy combination. Ploidy level of subsequent progeny derived from backcross with 2n-gametes of OA hybrid revealed that triploids from 2x-2x OA$\times$A, tetraploids from both 4x-2x, AA$\times$OA and OO$\times$OA, diploid from 2x-2x, O$\times$OA, and diploids or triploids from 2x-2x, A$\times$OA crosses were produced respectively.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.534-539
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• 2018

'Hwawang' is an early maturing and short statured rice cultivar adaptable to the rice-cash crop rotation system that was developed by the rice breeding team of the Department of Southern Crop, National Institute of Crop Science (NICS), Rural Development Administration (RDA), Korea, in 2012. This cultivar was derived from the cross of YR25867 (Hitomebore//YR21247-B-B-B-49-1/Sasanishiki BL4) and YR25866 (Akidagomachi//YR21247-B-B-B-49-1/Sasanishiki BL4) during the 2005/2006 winter season and was fixed as a homozygous line by a doubled haploid breeding system. In the replicated yield trial in 2009, a promising line (YR26253Acp26-1) showed a good phenotype and high yield potential, and so it was selected and designated as 'Milyang256'. The local adaptability test of 'Milyang256' was carried out at three locations from 2010 to 2012. It was named 'Hwawang' and had a high head rice ratio and good eating quality. The culm length of 'Hwawang' averaged 62 cm during the yield trials and was 10 cm shorter than that of 'Keumo'. The number of spikelets per panicle of 'Hwawang' was significantly lower than that of 'Keumo', but the number of tillers per hill was higher. This variety showed resistance to bacterial blight disease but was moderately susceptible to both leaf and neck blast. The milled rice yield of 'Hwawang' was 452 kg/10 a at the late transplanting stage of the local adaptability test. Thus, 'Hwawang' is well adapted to the rice-cash crop rotation system in the southern plain area. (Registration No. 5106)

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.396-405
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• 2018

The areas of soybean (Glycine max (L.) Merrill) cultivation in Gangwon-do have increased due to the growing demand for well-being foods. The soybean barcode system is a useful tool for cultivar identification and diversity analysis, which could be used in the seed production system for soybean cultivars. We genotyped cultivars using 202 insertion and deletion (InDel) markers specific to dense variation blocks (dVBs), and examined their ability to identify cultivars and analyze diversity by comparison to the database in the soybean barcode system. The genetic homology of "Cheonga," "Gichan," "Daewang," "Haesal," and "Gangil" to the 147 accessions was lower than 81.2%, demonstrating that these barcodes have potentiality in cultivar identification. Diversity analysis of one hundred and fifty-three soybean cultivars revealed four subgroups and one admixture (major allele frequency <0.6). Among the accessions, "Heugcheong," "Hoban," and "Cheonga" were included in subgroup 1 and "Gichan," "Daewang," "Haesal," and "Gangil" in the admixture. The genetic regions of subgroups 3 and 4 in the admixture were reshuffled for early maturity and environmental tolerance, respectively, suggesting that soybean accessions with new dVB types should be developed to improve the value of soybean products to the end user. These results indicated that the two-dimensional barcodes of soybean cultivars enable not only genetic identification, but also management of genetic resources through diversity analysis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.237-242
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• 2004

A system for the production of transgenic plants has been developed for tall fescue (Festuca arundinacea Schreb.) via Agrobacterium-mediated transformation of mature seed-derived embryogenic callus. Seed-derived calli were infected and co-cultured with Agrobacterium EHA101 carrying standard binary vector pIG121Hm encoding the hygromycin phosphotransferase (HPT), neomycin phosphotransferase II (NPTII) and intron-containing $\beta$-glucuronidase (intron-GUS) genes in the T-DNA region. The effects of several factors on transformation and the expression of the GUS gene were investigated. Inclusion of $200\mu\textrm{M}$ acetosyringone (AS) in inoculation and co-culture media lead to a increase in stable transformation efficiency. Transformation efficiency was increased when embryogenic calli were co-cultured for 5 days on the co-culture medium. The highest transformation efficiency was obtained when embryogenic calli were inoculated with Agyobacterium in the presence of 0.1% Tween20 and $200\mu\textrm{M}$ AS. Hygromycin resistant calli were developed into complete plants via somatic embryogenesis. GUS histochemical assay and Southern blot analysis of transgenic plants demonstrated that transgenes were successfully integrated into the genome of tall fescue.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.4
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• pp.273-280
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• 2008

In order to develop a simple and reproducible protocol for red top bentgrass (Agrostis alba L.), effect of different growth regulators was investigated for embrogenic calli induction and subsequent plant regeneration using mature seeds. MS medium containing 2 mg/L 2,4-D was optimal for embryogenic callus induction from mature seeds. The highest plant regeneration frequency (64.4%) was showed when the embryogenic callus tissues were cultured on N6 medium supplemented with 0.5 mg/L 2,4-D and 2 mg/L BA. Regenerated plantlets were grown normally when shoots transplanted to the soil. A high-frequency and efficient regeneration system from mature seeds would be helpful for molecular breeding of new variety of red top bentgrass through Agrobacterium-mediated genetic transformation.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.49-56
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• 2006

Gerber (Gerbera hybrida) is a valuable ornamental species grown as a potted plant and cut flowers. However, genetic variability within the gerbera genus is very limited. So it is absolutely needed to introduce and widen genetic resources into gerbera lines by genetic transformation. For the purpose, 18 Korean gerbera lines were screened to establish Agrobacterium-mediated genetic transformation procedure. In an experiment to select Korean gerbera lines which are amenable to Agrobacterium-inoculation, 12 lines turned out to be positive in Agrobacterium-inoculation. More callus were produced from BA 2ppm, Zeatin 2ppm, IAA 0.2ppm in pre-culture and regeneration medium (2X media) but there was no difference in the frequency of GUS expression rate. In another experiment to find out optimal condition for highly efficient Agrobacterium-inoculation, petiole and leaf explants have been treated with four different pre-culture periods, two different co-culture periods and two different Agrobacterium strains. As a result, high GUS expression has been showed from petiole and leaf explants treated no pre-culture period with LBA4404 Agrobacterium tumerfaciens, 5 day co-culture period and dipping treatment.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.51-55
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• 2005

Chinese leymus (Leymus chinensis Trin.) is a perennial grass that is widely distributed at high pH sodic and arid soil in the northeastern Asia. An efficient regeneration system was established through somatic embryogenesis of mature seeds to understand its high adaptability to harsh environmental conditions on the basis of molecular biology. The calli were efficiently induced (about $70\%$) from mature seeds on MS medium supplemented with $1.5\;\cal{mg/L}$ 2,4-D. Somatic embryos were formed from the surface of embryogenic callus on MS medium supplemented with $2.0\;\cal{mg/L}\;kinetin\;and\;0.5\;\cal{mg/L}$ NAA after 3 weeks of culture. Roots were induced from the shoot when transferred to MS medium without plant growth regulator for 1 week. Plant regeneration rate was $36\%$ and regenerated plantlets were grown to normal mature plants in pot. An efficient plant regeneration system in this study will be useful for molecular breeding of L. chinensis.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.43-48
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• 2004

As an initial step for future genetic manipulations to improve forage characteristics of Italian ryegrass (Lolium multiflorum Lam.), an efficient tissue culture system was established and the factors affecting plant regeneration were evaluated. MS medium containing 5mg/L 2,4-D was optimal for embryogenic callus induction from mature seed and had a strong effect on successive plant regeneration. The plant regeneration frequency was observed at above 70％ when embryogenic calli induced were transferred to N6 medium supplemented with 1mg/L 2,4-D and 5mg/L BA. Among several basic media tested, MS and N6 medium were optimal for callus induction and plant regeneration, respectively. Genotype was an important factor in plant regenerability. 'Jeanne' showed the highest regeneration frequency of 73％. A short tissue culture period and high-frequency regeneration system established in this study will be useful for molecular breeding of Italian ryegrass through genetic transformation.