• Korean Journal of Agricultural Science
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• v.39 no.4
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• pp.497-502
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• 2012

Since the year 2000, the production and consumption of broccoli have rapidly increased in Korea. And, the average production area and amount were about 1,700 ha and 29,000 ton for the past 5 years. Even with the increase of these cultivation and consumption, more than 95% of the broccoli seeds are currently imported from foreign countries such as Japan and Netherlands. Therefore, development of domestic broccoli varieties is needed to relieve Korean farmers' production cost for broccoli. In this situation, National Institute of Horticultural and Herbal Science (NIHHS) of Korea has tried to develop F1 hybrid varieties from elite lines that were obtained by microspore cultivation method from 2008. As the results, about 850 lines of broccoli were obtained and self-pollinated. Then their ploidy levels of the genome were confirmed to select double haploid (D.H.) lines. And the D.H. lines' horticultural traits were evaluated in open field. After the selection of 17 elite D.H. lines, they were cross-pollinated with a male sterile (MS) line to produce F1 hybrid seeds. After 2 to 3 years field trials of these F1 hybrid varieties at the area of Suwon, Gangneung, and Jeju respectively, two hybrid varieties such as 'Wongyo8011' and 'Wongyo8012' are selected for the application of variety protection. With these 4 years of research, we found that the microspore cultivation method is a powerful tool for the conventional breeding program, especially for the development of various inbred lines and even F1 hybrid varieties in short time.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.494-504
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• 2010

The effect of the addition of the fresh medium, volume of under solid medium in double layer culture as well as the medium change after pretreating microspores on the production of embryos in microspore culture of hot pepper (Capsicum annuum L.) has been studied. When cultured after heat pre-treatment, changing pretreatment media with fresh culture media proved to be more effective for embryo production rather than supplementing additional culture media. Heat-pretreating for 3 days turned out more effective for embryo production than pretreating for 1 or 2 days. In the case of anther pretreatment, the addition of fresh medium after culture was not effective for embryo production. In pretreating microspores, however, supplementing additional fresh culture media greatly improved embryo yield and quality. The best time point of media addition was 4 days after culture commenced, and the most effective number of times of media addition was one time addition. Moreover, the effective volume of added medium in double layer culture for embryo production was 1.5 ml. The addition of media more than 1.5 ml reduced both embryo yield and quality. Double layer medium was more effective for embryo development than liquid medium. When the volume of under solid medium increased ranging from 3 ml to 7 ml, more cotyledonary embryos were produced in either 5 ml or 7 ml compared to 3 ml, even though the total number of embryos were highest in 3 ml. These results can be used as an important data for establishing an efficient microspore culture system for producing high frequency of normal embryos in hot pepper.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.268-269
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• 2000

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.183-183
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• 2002

• Proceedings of the Korean Society of Crop Science Conference
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• 1991.10a
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• pp.12-13
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• 1991

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.10a
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• pp.16-17
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• 1990

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.10a
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• pp.18-19
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• 1990

• ALGAE
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• v.19 no.2
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• pp.79-90
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• 2004

Nuclear DNA contents of spermatia from eight ceramiacean and four dasyacean algae (Ceramiales, Rhodophyta) and microspores from two land plants were estimated by fluorescence microscopic image processing and their nuclear SSU rDNA sequence data were analyzed. In frequency distribution patterns, the DAPI-stained nuclear volume (NV) of spermatia showed two peaks corresponding to 1C and 2C. Nuclear 2C DNA contents estimated from NV were 0.45-2.31 pg in ceramiacean and 0.40-0.57 pg in dasyacean algae and 8.42-9.51 pg in two land plants, Capsicum annuum and Nicotiana tabacum. By nuclear patterning of vegetative cells derived from an apical cell, 2C DNA contents of spermatia were 2.31 pg in an alga having uninucleate and non-polyploid nucleus (Aglaothamnion callophyllidicola), 0.45-1.94 pg in algae having uninucleate and polyploid nucleus (Antithamnion spp. and Pterothamnion yezoense), and 0.40-0.62 pg in algae having multinucleate and non-polyploid nuclei (Griffithsia japonica and dasyacean algae). Each mature spermatium and microspore (pollen grain) seemed to have a 2C nucleus, which may provide a genetic buffering system to protect the genetic content of a spermatium and microspore from potentially lethal mutations. Nuclear DNA content and SSU rDNA sequence of Antithamnion sparsum from Korea were reasonably different from those of Antithamnion densum from France. The data did not support the previous taxonomic studies that these two taxa could be conspecific.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.251-256
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• 2000

Astragalus membranaceus has flowers that are similar to that of the legume family, but shows poor bearing when self-pollination is induced. Thus, this study was carried out observing the ripening procedure of pistils and stamens and development stages of pollen in the context of the birth and growth of the flower. As to the bearing of the flower of A. membranaceus, few pod setting and 13% pod setting were observed when self-pollination is induced by paper-bag covering or artificial pollination treated respectively. The result indicates that A. membranaceus is a cross-pollination plant. A pistil grew faster than a stamen until just before blooming. The flower size was about 17.0mm$\times$4.0mm. Pistils and stamens had the same length after flowering. Pollen mother cells passed through meiosis and mitosis when its length reached around 3.5mm, thus creating the tetrade when 4 mm long. Pollen attained full growth when the bud was about 10mm long. An anther was found to tend to dehisce when the length of a bud reached around 12.0mm. As to the shape of pollen, about 70 % were normal. 1% and 30 % were small or empty pollen respectively. The result indicates that pollen of A. membranaceus attains full growth just before anther dehiscence which occurs before blooming while pistils grow faster than stamens until before flowering.

• Journal of Life Science
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• v.19 no.8
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• pp.1016-1022
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• 2009

Tapetum is the tissue in which nutrients are supplied to the developing microspore in angiosperm anther. At tetrad stage of microspore, the tapetal cells show maximum development, but they began to be degenerated by apoptotic programmed cell death (PCD) after sporopollenin accumulation in the pollen wall. The initial step of PCD was observed as vacuolar fusion. After that, cytoplasmic condensation and nuclear fragmentation followed. Lipid droplets are degenerated at a relatively late stage of PCD, and orbicular bodies are the last remains in tapetal cells. The cell wall was relatively resistant against vacuolar enzymes in tapetal cells; it was considered the last structure remaining during programmed cell death of tapetum in ginseng anther.