• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.4
• /
• pp.455-461
• /
• 1987

The ovaries or the ovules of grasses were pollinated and cultured in vitro to raise the interspecific or the intergeneric hybrids between tall fescue, meadow fescue, and Italian ryegrass. The isolated and suface-sterili-zed pistils were dusted with compatible pollens on stigma, on stump after removing stigma, or on excised ovule. Furthermore, the fertilized ovaries and ovules were cultured on MS, M6, or White's media and treated with plant growth regulators: IAA, kinetin, BA to promote embryo development and seed maturity. The in vitro fertilization in grass species ranged from 44 to 92% depending on ovary and pollen parents. The stigmatic pollination was resulted in 67.8% fertilization, the stump pollination 89.0%, and the excised ovule pollination 61.0%, repectively. White's medium was the most effective to provide embryo development and seed maturity in grass species. And the combined treatment of IAA 10mg/$\ell$, kinetin 0.2mg/$\ell$, was better than the non-treatment. Only two seedlings, one complete and one abnormal with root formation were obtained from 127 ovaryies cultured. The anatomy of ovules in vitro cultured was revealed the differentiation of vascular system and meristematic tissue, and the formation of sclerenchyma cells inside ovule.

• Korean Journal of Plant Tissue Culture
• /
• v.25 no.2
• /
• pp.103-107
• /
• 1998

Tobacco proembryos were irradiated with 100 Gy of heavy-ion beams($^{14}\textrm{N}$, $^{20}\textrm{Ne}$: 135 Mev/u) after 24 to 96 hours of pollination as a mutagen and screened $\textrm{M}_{1}$ generation for morphological mutants and salt-tolerant plants. Morphological and physiological characteristics of the salt-tolerant plants derived from the irradiated proembryo are discussed in this report. Mutants irradiated proembryos with the beams after pollination produced various kinds of morphological variation. A total of 17 salt-tolerant plants were selected from tobacco cultivar (BY-4) by treatment with $^{14}\textrm{N}$ beam. Shapes of filament and pollen grain of most salt-tolerant plants were abnormal compared with non-irradiated wild type, and seeds weight and fertility obviously decreased. The germination rates of the several $\textrm{M}_{2}$ lines on the saline and the mannitol condition were higher than that of wild type.

• Horticultural Science & Technology
• /
• v.33 no.1
• /
• pp.83-92
• /
• 2015

xBrassicoraphanus line BB#5, a new synthetic intergeneric hybrid between Brassica rapa L. ssp. pekinensis and Raphanus sativus L. var. rafiphera induced by N-methyl-N-nitroso-urethane mutagenesis in microspore culture, shows high seed fertility and morphological uniformity. Dual-color fluorescence in situ hybridization (FISH) using 5S and 45S rDNA probes and genomic in situ hybridization (GISH) using B. rapa genomic DNA probe were carried out to analyze the chromosome composition and the meiosis pairing pattern compared to its parental lines. The somatic chromosome complement is 2n = 38, which consists of 17 metacentric and two submetacentric chromosomes with lengths of 2.18 to $5.01{\mu}m$. FISH karyotype analysis showed five and eight pairs of 5S and 45S rDNA loci. GISH meiosis pairing analysis showed that 19 complete bivalents were most frequent and accounted for 42% of the 100 pollen mother cells examined. Based on chromosome number, size, morphology, rDNA distribution, and meiosis pairing pattern, both parental genomes of B. rapa and R. sativus appear to exist in xBrassicoraphanus line BB#5, demonstrating its genome integrity. Such stable chromosome constitutions and meiotic pairing patterns in somatic and meiotic cells are very rare in natural and synthetic intergeneric hybrids. Chromosomal studies and genetic and phenotypic changes in allopolyploids a re discussed. The results p resented h erein will b e usef ul f or f urther g enomic s tudy o f xBrassicoraphanus lines and their improvement as promising new breeding varieties.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.18 no.4
• /
• pp.73-85
• /
• 1991

Rhododendron mucronulatum for. albiflorum, native species is a shrub that has white flowers on May to June, and rare species endangered by people's rash digging or cutting. But its physiological ecological characteristics and propagation method are not being known at all. Therefore, this study was executed to utilize this species as the planting material for landscaping by analysing its habitat environment and growth form, and also experimenting its seed and vegetative propagation, and it field culture and utilization. The results are as follows; 1. The elevation, gradient and direction of this species were 295-1,350m, 10-36$^{\circ}$, northwest respectively. It was found that the species is shade-liking plant that grows under forest cover of average 51.33%. 2. The soil pH and water content of its habitat were 5.4, 25.41% respectively. The organic matter content was 6.29% that was higher than 3.2%, the average organic matter content of forest soil in Korea. 3. Representative plant community within which this species was living was Quercus mongolica community, and its main neighboring species were Lindea obtusiloba, Fraxinus sieboldiana, Rhus trichocarpa, Rhododendron Schlippenbachii, Rododendron mucronulatum. 4. The leaf length and width of this species were 39.18mm, 12.60mm respectively. This result showed that generally its leaf size was larger than that of R. micranthum, R. yedoense var. poukhanense and R. mucronulatum var. ciliatum and smaller than that of R. mucronulatum and R. schlippenbachii. 5. The whole size of its pollen was, as 59${\times}$61$\mu\textrm{m}$, the largest of plants of Rhododendron family including R. mucronulatum and R. mucronulatum var. ciliatum. 6. The result of seed germination experiment at intervals of 5$^{\circ}C$ from 15$^{\circ}C$ to 30$^{\circ}C$ presented the highest germination rate of 94.7% at 20$^{\circ}C$ numerically, but high percent germination at all temperature levels without significant difference. And the seed of this plant proved to be sun-liking seed at requiring dormancy in germination. 7. Through seed germination experiment by treatment of growth regulators such as GA. Thiourea and Kinetin under dark condition, it was found that the effect of GA treatment on germination increase and acceleration was the highest. 8. In greenwood cutting, rooted rate by treatment of various concentration of IBA and NAA on clay and vermiculite bed was not wholly high, but 100ppm plots of both IBA and NAA of clay bed showed relatively good rooted rate. 9. As result of field culture experiment for finding out optimum growth temperature and light intensity, growth conditions such as height, number of leaves, fresh weight and chlorophyll contents were the best at night/day temperature of 20/25$^{\circ}C$ and under 1/2sun. Also, the photosynthetic rate was the highest at 25$^{\circ}C$. Accordingly, it was found that optimum temperature and light intensity for growth of this plant are 25$^{\circ}C$ (day temperature), 50% of natural light respectively.

• Horticultural Science & Technology
• /
• v.31 no.4
• /
• pp.517-521
• /
• 2013

A new cultivar Dendranthema grandiflourm 'Dream Round' was developed at Gyeonggi-do Agricultural Research & Extension Services (GARES), Korea in 2010. The variety 'Dream Round' was initially derived from a cross in 2006 between 'Hebo' a seed parent, a spray chrysanthemum cultivar with white anemone type, and 'Samos' as a pollen parent, a spray chrysanthemum variety with white anemone type. The cultivar has anemone type with white petals. Trial evaluation was conducted from 2008 to 2010 for the selection of that cultivar, including a shading culture in spring and a retarding culture in summer. The flowering time of 'Dream Round' was October 24th, and year-round flowering was possible by shading or lighting treatment. The diameter of flower of 'Dream Round' was 34.1 mm. Numbers of flowers per stem and petals per flower of 'Dream Round' were 12.8 and 26.1, respectively. Its leaf color was green (Green Group 147A) and plant height was 92.4 cm. Days to flowering of 'Dream Round' under the short day treatment was about 54 in spring, and diameter of flower of 'Dream Round' was 34.2 mm in the summer. The vase life of 'Dream Round' was 21.7 days in autumn.

• Journal of Korean Society of Forest Science
• /
• v.21 no.1
• /
• pp.1-34
• /
• 1974

The author intended to investigate external and internal changes in the cone structure, changes in water content, sugar, fat and protein during the period of seed maturation which bears a proper germinability. The experimental results can be summarized as in the following. 1. Male flowers 1) Pollen-mother cells occur as a mass from late in April to early in May, and form pollen tetrads through meiosis early and middle of May. Pollen with simple nucleus reach maturity late in May. 2) Stamen number of a male flower is almost same as the scale number of cone and is 69-102 stamens. One stamen includes 5800-7300 pollen. 3) The shape is round and elliptical, both of a pollen has air-sac with $80-91{\mu}$ in length, and has cuticlar exine and cellulose intine. 4) Pollen germinate in 68 hours at $25^{\circ}C$ with distilled water of pH 6.0, 2% sugar and 0.8% agar. 2. Female flowers 1) Ovuliferous scales grow rapidly in late April, and differentiation of ovules begins early in May. Embryo-sac-mother cells produce pollen tetrads through meiosis in the middle of May, and flower in late May. 2) The pollinated female flowers show repeated divisions of embryo-sac nucleus, and a great number of free nuclei form a mass for overwintering. Morphogenesis of isolation in the mass structure takes place from the middle of March, and that forms albuminous bodies of aivealus in early May. 3. Formation of pollinators and embryos. 1) Archegonia produce archegonial initial cells in the middle and late April, and pollinators are produced in the late April and late in early May. 2) After pollination, Oespore nuclei are seen to divide in the late May forming a layer of suspensor from the diaphragm in early June and in the middle of June. Thus this happens to show 4 pro-embryos. The organ of embryos begins to differentiate 1 pro-embryo and reachs perfect maturation in late August. 4. The growth of cones 1) In the year of flowering, strobiles grow during the period from the middle of June to the middle of July, and do not grow after the middle of August. Strobiles grow 1.6 times more in length 3.3 times short in diameter and about 22 times more weight than those of female flower in the year of flowering. 2) The cones at the adult stage grow 7 times longer in diameter, 12-15 times shorter diameter than those of strobiles after flowering. 3) Cone has 96-133 scales with the ratio of scale to be 69-80% and the length of cone is 11-13cm. Diameter is 5-8cm with 160-190g weight, and the seed number of it is 90-150 having empty seed ratio of 8-15%. 5. Formation of seed-coats 1) The layers of outer seed-coat become most for the width of $703{\mu}$ in the middle of July. At the adult stage of seed, it becomes $550-580{\mu}$ in size by decreasing moisture content. Then a horny and the cortical tissue of outer coats become differentiated. 2) The outer seed-coat of mature seeds forms epidermal cells of 3-4 layers and the stone cells of 16-21 layers. The interior part of it becomes parenchyma layer of 1 or 2 rows. 3) Inner seed-coat is formed 2 months earlier than the outer seed-coat in the middle of May, having the most width of inner seed-coat $667{\mu}$. At the adult stage it loses to $80-90{\mu}$. 6. Change in moisture content After pollination moisture content becomes gradually increased at the top in the early June and becomes markedly decreased in the middle of August. At the adult stage it shows 43~48% in cone, 23~25% in the outer seed-coat, 32~37% in the inner seed-coat, 23~26% in the inner seed-coat and endosperm and embryo, 21~24% in the embryo and endosperm, 36~40% in the embryos. 7. The content compositions of seed 1) Fat contents become gradually increased after the early May, at the adult stage it occupies 65~85% more fat than walnut and palm. Embryo includes 78.8% fat, and 57.0% fat in endosperm. 2) Sugar content after pollination becomes greatly increased as in the case of reducing sugar, while non-reducing sugar becomes increased in the early June. 3) Crude protein content becomes gradually increased after the early May, and at the adult stage it becomes 48.8%. Endosperm is made up with more protein than embryo. 8. The test of germination The collected optimum period of Pinus koraiensis seeds at an adequate maturity was collected in the early September, and used for the germination test of reduction-method and embryo culture. Seeds were taken at the interval of 7 days from the middle of July to the middle of September for the germination test at germination apparatus.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.27 no.4
• /
• pp.371-384
• /
• 1982

Highly cold tolerant varieties are requested not only at high latitute cool area but also tropical high elevated areas, and the required tolerance is different from location to location. IRRI identified 6 different types of cold tolerance required in the world for breeding purpose; a) Hokkaido type, b) Suweon type, c) Taipei 1st season type, d) Taipei 2nd season type, e) Tropical alpine type and, f) Bangladesh type. The cold tolerance requested in Korea is more eargent in Tongil group cultivars and their required tolerance is the one such as the physiological activities at low temperature are as active as in Japonica group cultivars at least during young seedling stage and reproduction stage. With conventional Japonica cultivars, such cold tolerant characters are requested as short growth duration but stable basic vegetative growth, less sensitive to high temperature and less prolonged growth duration at low temperature. The methods screening for cold tolerance were developed rapidly after the Tongil cultivar was reliesed. The facilities of screening for cold tolerance, such as, low temperature incubator, cold water tank, growth cabinet, phytotron, cold water nursery in Chuncheon, breeding nursery located in Jinbu, Unbong and Youngduk, are well established. Foreign facilities such as, cold water tank with the rapid generation advancement facilities, cold nurseries located in Banaue, Kathmandu and Kashimir may be available for the screening of some limitted breeding materials. For the reference, screening methods applied at different growth stages in Japan are introduced. The component characters of cold tolerance are not well identified, but the varietal differences in a) germinability, b) young seedling growth, c) rooting, d) tillering, e) discolation, f) nutrition uptake, g) photosynthesis rate, h) delay in heading, i) pollen sterility, and j) grain fertility at low temperature are reported to be distinguishable. Relationships among those traits are not consistent. Reported studies on the inheritance of cold tolerance are summarized. Four or more genes are controlling low temperature germinability, one or several genes are controlling seedling tolerance, and four or more genes are responsible for the pollen fertility of the rice treated with cold air or grown in the cold water nursery. But most of those data indicate that the results may come out in different way if those were tested at different temperature. Many cold tolerant parents among Japonicas, Indicas and Javanicas were identified as the results of the improvement of cold tolerance screening techniques and IRTP efforts and they are ready to be utilized. Considering a) diversification of germ plasm, b) integration of resistances to diseases and insects, c) identification of adaptability of recommending cultivars and, d) systematic control of recommending cultivars, breeding strategies for short term and long term are suggested. For short term, efforts will be concentrated mainly to the conventional cultivar group. Domestic cultivars will be used as foundation stock and ecologically different foreign introductions such as from Hokkaido, China or from Taiwan, will be used as cross parents for the adjustment of growth durations and synthsize the prototype of tolerances. While at the other side, extreme early waxy Japonicas will be crossed with the Indica parents which are identified for their resistances to the diseases and insects. Through the back corsses to waxy Japonicas, those Indica resistances will be transfered to the Japonicas and these will be utilized to the crosses for the improvement of resistances of prototype. For the long term, efforts will be payed to synthsize all the available tolerances identified any from Japonicas, Indicas and Javanicas to diversify the germ plasm. The tolerant cultivars newly synthsized, should be stable and affected minimum. to the low temperature at all the growing stages. The resistances to the diseases and insects should be integrated also. The rapid generation advancement, pollen culture and international cooperations were emphasized to maximize the breeding efficiency.

• Korean Journal of Breeding Science
• /
• v.40 no.1
• /
• pp.31-38
• /
• 2008

This experiment was carried out to improve the anther culture efficiency of barley (Hordeum vulgare L.). Callus induction rates from anther cultures of the five domestic naked barley and four unhulled varieties ranged from 0 to 5.6%, and plant regeneration rate to callus was 30.4% in the donor plants grown in a greenhouse during winter, among which the green plant regeneration rates ranged from 0 to 4.4%. Plant regeneration rate was 30.4% in the donor plants grown in a greenhouse during winter, whereas 21.3% in the normal field condition in spring. In addition, callus induction rates were 19.2% in plants grown in a normal field and 7.2% in drought-stressed condition, respectively. Being Considered the anther culture efficiency affected by the sampling time, the optimum sampling stage of anthers was 3~4 days before heading when the length between the 1st and 2nd auricles reaches 5 to 10 cm and at the uninucleate of pollen which the tip of the 2nd auricle aligns with the middle of panicle in the leaf sheath. Best callus induction rates came from the anthers stored at $4^{\circ}C$ for 3 weeks in a 10 to 15 cm diameter polyethylene bag with 5 to 10 panicles and Duwonchapssalbori and Saessalbori showed the higher induction rate of 4.8% and 1.7%, respectively.

• Journal of the Korean earth science society
• /
• v.26 no.6
• /
• pp.597-602
• /
• 2005

The Late Quaternary palynoflora from an archaeological site in Piseo-ri, Muan, Korea consists predominately of deciduous broadleaved angiosperms and subordinately of herbs and conifers. Dominant taxa are Polypodiaceae, Taxodiaceae-Cupressaceae-Taxaceae, Alnus, Carpinus, deciduous Quercus, Compositae and Gramineae. The palynoflora dated 43,000-18,000 yr BP, corresponding to the last glacial period, is similar to the modern vegetation of the cool temperate deciduous broadleaved forest in the middle part of the Korean Peninsula. Based on palynofloral composition, three palynozones are recognized. Zone I represents a cool temperate deciduous broadleaved forest, composed of Polypodiaceae, Taxodiaceae-Cupressaceae-Taxaceae, Alnus and D. Quercus, and is characterized by persistent occurrence of warm temperate taxa. Zone II shows drastic decrease in Polypodiaceae, Taxodiaceae-Cupressaceae-Taxaceae, and increase in herbs. This zone reflects a cool temperate deciduous broadleaved forest with scattered open grasslands. Zone III is characterized by dominance in herbs and increase in conifers. The palynofloral composition suggests a cool temperate climate, and variation in occurrences of main taxa indicates that climatic conditions gradually became cold and dry.

• Journal of Plant Biotechnology
• /
• v.38 no.2
• /
• pp.105-116
• /
• 2011

Transgenic zoysiagrass (Zoysia japonica Steud.) expressing the bar gene inserted in the plant genome has been generated previously through Agrobacterium tumefaciens-mediated transformation. The GM zoysiagrass (event: JG21) permits efficient management of weed control of widely cultivated zoysiagrass fields, reducing the frequency and cost of using various herbicides for weed control. Now we have carried out the environmental risk assessment of JG21 prior to applying to the governmental regulatory agency for the commercial release of the GM turf grass outside of test plots. The morphological phenotypes, molecular analysis, weediness and gene flow from each test plot of JG21 and wild-type zoysiagrasses have been evaluated by selectively analyzing environmental effects. There were no marked differences in morphological phenotypes between JG21 and wild-type grasses. The JG21 retained its stable integration in the host plant in T1 generation, exhibiting a 3:1 segregation ratio according to the Mendelian genetics. We confirmed the copy number (1) of JG21 by using Southern blot analysis, as the transgenic plants were tolerant to ammonium glufosinate throughout the culture period. From cross-fertilization and gene flow studies, we found a 9% cross-pollination rate at the center of JG21 field and 0% at distances over 3 m from the field. The JG21 and wild-type zoysiagrass plants are not considered "weed" because zoysiagrasses generally are not dominant and do not spread into weedy areas easily. We assessed the horizontal gene transfer (HGT) of the transgene DNA to soil microorganisms from JG21 and wild-type plants. The bar gene was not detected from the total genomic DNA extracted from each rhizosphere soil of GM and non-GM Zoysia grass fields. Through the monitoring of JG21 transgene's unintentional release into the environment, we found no evidence for either pollen mediated gene flow of zoysiagrass or seed dispersal from the test field within a 3 km radius of the natural habitat.