• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.306-311
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• 2008

Proper tree vigor and crop load were determined for 'Fuji'/M.9 apple trees in high density planting system from 2001 to 2003. Leaf/fruit ratio was highly correlated to mean fruit weight (y=1.715x+205.02, $R^2=0.66^{**}$) and yield (y=-35.l56x+5963.7, $R^2=0.44^{**}$). In addition, there was a significant correlation between the number of leaves per tree and mean fruit weight. However, crop load did not affect tree growth, soluble solids content of fruit, and Hunter a value. To harvest the fruits heavier than 300 g without biennial bearing, it was appropriate to crop 55 to 64 fruits in a tree with 55 leaves per fruit of adult tree. The good indices for proper tree vigor could be 20 to 25 cm of mean shoot length and above 95% of shoot termination rate. Moreover, no secondary growth and 20 to 30% of spur formation could be the indices for highly productive tree vigor.

• Plant Biotechnology Reports
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• v.3 no.3
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• pp.175-182
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• 2009

Simple, reproducible, high frequency, improved plant regeneration protocol in Eastern Cottonwood (Populus deltoides) clones, WIMCO199 and L34, has been reported. Initially, aseptic cultures established from axillary buds of nodal segments from mature plus trees on MS liquid medium supplemented with $0.25mg\;1^{-1}$ KIN and $0.25mg\;1^{-1}$ IAA. Nodal and internodal segments were found to be extra-prolific over shoot apices during course of aseptic culture establishment, while $0.25mg\;1^{-1}$ KIN concentration played a stimulatory role in high frequency plant regeneration. Diverse explants, such as various leaf segments, internodes, and roots from in vitro raised cultures, were employed. Direct plant regeneration was at high frequency of 92% in internodes, 88% in leaf segments, and 43% in root segments. This led to the formation of multiple shoot clusters on established culture media with rapid proliferation rates. Many-fold enhanced shoot elongation and growth of the clusters could be achieved on liquid MS medium supplemented with borosilicate glass beads, which offer physical support for proliferating shoots leading to faster growth in comparison to semi-solid agar or direct liquid medium. SEM examination of initial cultures confirmed direct plant regeneration events without intervening calli. In vitro regenerated plants induced roots on half-strength MS medium with $0.15mg\;1^{-1}$ IAA. Rooted 5- to 6-week-old in vitro regenerated plants were transferred into a transgenic greenhouse in pots containing 1:1 mixture of vermicompost and soil at $27{\pm}2^{\circ}C$ for hardening and acclimatization. 14- to 15-week-old well-established hardened plants were transplanted to the field and grown to maturity. The mature in vitro raised poplar trees exhibited a high survival rate of 85%; 4-year-old healthy trees attained an average height of 8 m and an average trunk diameter of 25 cm and have performed well under field conditions. The regeneration protocol presented here will be very useful for undertaking genetic manipulation, providing a value addition to Eastern Cottonwood propagation in future.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.511-516
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• 2010

The process to acquire intron-GUS gene-expressed transformants from somatic embryos (including embryogenic calli) of Rosa hybrida cv. 'Sweet Yellow' using Agrobacterium-meditated transformation method was reported in this study. Somatic embryos including embryogenic calluses were infected with Agrobacterium tumefaciens AGL1 strain (O.D = 0.7~1.6) including intron-GUS gene for 30 min, and were co-cultured for 3 days. After co-cultivation, they were cultured on embryo germination medium (EGM) supplemented with $250\;mg{\cdot}L^{-1}$ cefotaxim at $4^{\circ}C$ for 7 days. Then, transient GUS gene expression was observed. Shoots were regenerated from the shoot primodia induced from the intron-GUS gene-transferred either somatic embryos or embryogenic calli cultured on EGM supplemented with both cefotaxim $250\;mg{\cdot}L^{-1}$ and ppt $2\;mg{\cdot}L^{-1}$. Before induction of rooting from shoots cultured on shoot growing medium supplemented with both cefotaxim $250\;mg{\cdot}L^{-1}$ and ppt $2\;mg{\cdot}L^{-1}$, the shoots were cultured on multi-shoot induction medium supplemented with both cefotaxim $250\;mg{\cdot}L^{-1}$ and ppt $2\;mg{\cdot}L^{-1}$ to induce multi-shoots. When expression of the gene from a part of the multi-shoots was identified by GUS transient assay, the putative transgenic multishoots were transferred to rooting medium supplemented with cefotaxim $250\;mg{\cdot}L^{-1}$. After the formation of healthy roots, transgenic plantlets were transferred to the greenhouse after acclimatization. The expression rate of the intron-GUS gene in the multi-shoots was 100%.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.49-55
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• 2017

We investigated the callus induction and plant regeneration ability of 16 maize genotypes, including the Korean inbred lines, using 9 to 15 day-old immature zygotic embryos from maize grown in pots and from field cultures. Immature zygotic embryos placed on MS medium supplemented with L-proline 0.7 g/L, MES 0.5 g/L, Dicamba 1.5 mg/L, 2,4-D 0.5 mg/L, $AgNO_3$ 4 mg/L, and sucrose 20 g/L, showed the highest frequency of callus induction. The highest number of shoots regenerated when the embryogenic callus were transferred to MS medium supplemented with 5 mg/L zeatin. The root formation was observed when shoots were grown on MS medium supplemented with 0.2 mg/L indole-3-butyric acid (IBA). Additionally, under the same culture conditions, immature zygotic embryos from maize grown in the field also had a high frequency of plant regeneration. Except one genotype, 15 genotypes showed callus induction and shoot regeneration. Among the 16 genotypes tested, H99, B98, HW3, and B73 yielded the best plant regeneration. H99 showed maximum shoot formation from the primary embryogenic callus. The results suggest that genotypes and growth conditions of the maize plant plays very important roles for enhancing the embryogenesis competence of immature zygotic embryos. The successful regeneration from immature zygotic embryos of maize inbred lines provides a basis for molecular breeding of new cultivars by genetic transformation.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.37-45
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• 2007

The genetic transformation of watermelon by Agrobacterium has been known very difficult and a few successful cases have been reported by obtaining the direct shoot formation. However, since this direct shoot formation is not guaranteed the stable transformation, the stable transformation with reproducibility is required by a different approach such as a callus induced manner. The best conditions for inducing the callus from cotyledon and root explants of watermelon were 2 mg/L zeatin + 0.1 mg/L IAA and 2 mg/L BA + 0.1 mg/L 2,4-D, respectively. The GFP expression in the callus was identified and monitored through fluorescent microscopy after transformation with pmGFP5-ER vector. Paromomycin rather than kanamycin was used for selecting the nptll gene expression because it was more effective to select the watermelon explants. Four different callus types were observed and the solid green callus showed stronger GFP expression. The highest frequency of GFP expression in the callus developed from cotyledon was 9.0% (WM8 inbred line), while the highest frequency from root was 8.3% (WM6 inbred line). The WMV-CP was transformed using the method of GFP transformation and the genetic transformation of WMV-CP was confirmed by PCR and Southern blot analysis. Here we present a system for callus induction of watermelon explant and the callus induced method would facilitate the establishment of stable watermelon transformation.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.34-39
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• 2007

Whole plants were regenerated from callus induced from leaf explants in hybrid kiwi (Actinidia deliciosa${\times}$A. arguta). Callus was induced from leaf explants which cultured on MS solid medium supplemented with combination of auxin (2,4-D, NAA: 0.1~0.5 mg/l) and cytokinin (BA: 0.1~0.2 mg/l). them, the highest callus formation (96.2%) was obtained from the treatment of 0.5 mg/1 2,4-D+0.1 mg/l NAA+0.05 mg/l BA. In the experiment of adventitious shoots induction from primary shoots, only a few shoots were produced in the treatment of 1.0 mg/l BA+0.05 mg/l IBA or 2.0 mg/l BA+0.05 mg/l lBA. As the callus were transferred to the secondary shoot-inducing medium, multiple shoots were obtained from the medium supplemented with 1.0, 2.0 or 5.0 mg/l zeatin in addition to the mixed treatments of BA, thidiazuron (TDZ) or zeatin. However, no multiple shoots were induced on the BA-contained medium of concentrations. Therefore it turned out that addition of BA to medium was less effective for induction of multiple shoots from callus in Actinidia deliciosa${\times}$A. arguta. For producing adventitious roots from shoots, the best frequency of rooting (83.3%) were recorded on the treatment of in vitro rooting (Standardi (St)+1.0 mg/l IBA). On the other side, the lowest result (40.0%) were shown in the treatment of 500 mg/l IBA, 1 hr. Whole plants with shoots and roots were recovered and acclimatized successfully.

• Plant Resources
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• v.5 no.1
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• pp.29-44
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• 2002

In this study, plant regeneration through in vitro culture from plantlet stems of Yooja (C. junos Sieb.) and trifoliate orange (P. trifoliata Rafin.) was attempted to make mass-production system of virus-free plants having the same genotype with mother plant. In order to investigate physiological change depending on the developmental stage of plant regeneration, the changes of total protein, peroxidase and esterase activity and their isozyme patterns as well were examined in 1/2 MS medium. The results are as follows : 1. The MS medium for the optimal callus induction and shoot formation was utilized. The medium was supplemented either with 2,4-D and Kinetin or with BA and NAA. The optimal concentrations were the combination of 1.0mg/ 2,4-D +0.3mg/ Kinetin and 1.0mg BA +0.3mg NAA in callus induction and shoot formation, respectively. 2. For the plant regeneration from somatic embryos, 1/2 MS medium was used with supplements of growth regulators (free, 1.0mg/ IBA +1.0mg/ BA ,0.5mg/ IBA +0.5mg/ BA). Shooting and rooting were the best in the treatment of 0.5mg/ IBA and 0.5mg/ BA combination. 3. The total protein content has a tendency of increase with the developmental stage of embryo, but it was decreased at the plantlet. Also it was the highest at 8 and 6 weeks stage in C. junos Sieb. and P. trioliata Rafin, respectively. In the SDS-PAGE pattern of protein, C. junos Sieb. showed bands of 29.0 and 40kDa at 10 weeks. The 45,66 and 97.4 kDa bands at 10 weeks of culture were shown in P. trifoliata Rafin. 4. The highest esterase activity was shown at the 6 and 8 weeks of culture in C.junos Sieb. and P. trifoliata Rafin.., respectively. 5. Esterase isozyme patterns were shown difference according to the developmental stage. In C. junos Sieb. a new band was observed at pl 7.7 following 4 weeks culture. On the other hand, new bands in P. trifoliata Rafin. were observed at pl 7.5~6.5 following 4 and 6 weeks culture, respectively.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.121-129
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• 2011

As the molecular breeding was progressed, many plant transformation techniques were attained for improving transformation accuracy and used to produce useful transgenic plants. Day by day, new varieties were developed so new transformation techniques required for these newly developed varieties. Carnation (Dianthus caryophyllus L.) is a popular and economically important ornamental plant, all over the world. Keeping this in view, we selected 18 varieties of D. caryophyllus L. commonly available in the market and did optimization of culture conditions for more efficient tissue culture and to get higher number of plants via micro-propagation. Four varieties namely Yellowdotcom, Jakarta, Belmonte, Polartessino etc. were selected for organ culture studies from single cell line. The optimum growth was recorded in the MS media supplied with sucrose 3%, NAA 1.0 mg/L and TDZ 1.0 mg/L. except Belmonte, in which, BA 1.0 mg/L was found to be the best combination, in place of TDZ, rest ingredients were same. The most efficient coagulating agent used to obtain higher number of plant from callus was phytagel 0.3%. The most effective explant for higher shoot formation was stem in which 80.2% shoot formation was recorded. It also reduced culture periods by 6 days.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.143-153
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• 2016

Plant regeneration via organogenesis and somatic embryogenesis was investigated in Korean soybean cultivars including Cheongja 3, Jinpumkong 2, Taekwangkong and Uram. Cotyledon, cotyledon+hypocotyl and hypocotyl segments of 7-day-old seedlings were cultured on MS medium containing various concentration (0, 1, 2 and 4 ㎎/L) of BA and TDZ. The results showed that MS medium supplemented with BA 2.0 ㎎/L yielded the highest shoot formation ratio of 83.3%. In 4 cultivars, Taekwangkong showed the highest ratio of shoot formation. When various sizes of immature cotyledons (S: 1∼ 2 ㎜, M: 3∼5 ㎜, L: 6∼8 ㎜) were tested on MS medium containing 2,4-D 40 ㎎/L for somatic embryogenesis, the optimum size for embryogenic callus induction was 3∼5 ㎜ in length of immature cotyledons. In 4 cultivars, Taekwangkong showed the highest percentage of embryogenic callus induction. The results indicate that Taekwangkong is the best soybean cultivar for plant regeneration via organogenesis and embryogenic callus induction among the 4 cultivars.

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.261-265
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• 2010

This experiment was carried out in order to determine proper plant growth regulators (PGR) and their concentrations for direct shoot induction and somatic embryogenesis from leaf tissue cultures of Muscari armeniacum 'Early Giant'. Direct shoot formation from the leaf explant culture was effective only on a half-strength MS medium containing $0.1mg{\cdot}L^{-1}$ 2,4-D, while embryogenesis was occurred on a half-strength MS medium containing $0.1{\sim}1.0mg{\cdot}L^{-1}$ IPA or without PGR. The regenerated bulblets derived from embryos or shoots were harvested and transplanted into a greenhouse. The sprouting percentage of bulblets obtained from different culture media ranged from 80 to 100% and growth of quality bulblets was enhanced when the bulblets were harvested from the medium containing $0.1mg{\cdot}L^{-1}$ NAA and $1.0{\sim}3.0mg{\cdot}L^{-1}$ IPA.