• Korean Journal of Plant Resources
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• v.36 no.5
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• pp.490-495
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• 2023

This study was conducted to investigate the growth and fruit characteristics of recently introduced or bred varieties in Korea and to review domestic adaptability. As for the sprouting rate among cultivars, 'Stella' was the highest at 91.6%, followed by 'My Heart' (78.3%), 'IFG-6' (77.3%), and 'Hongju Seedless' (73.2%). As for the flower incidence rate by cultivar, 'Stella' was the highest at 113.5%, and 'IFG-6' had a lower flower incidence at 45.3% compared to other cultivars. The diameter of shoots was less than 11.0 mm in the other three cultivars except for 'Hongju Seedless', and 'Hongju Seedless' was the thickest at 12.5 mm and 'Stella' was the thinnest at 9.6 mm. The berry weight of 'My Heart' was 11.3 g, heavier than other cultivars, followed by 'Stella', 'IFG-6' and 'Hongju Seedless'. Soluble sugar content at harvest time by cultivar was about 19.0°Bx or higher, with 'IFG-6' having the highest level of 20.2°Bx, followed by 'My Heart', 'Stella', and 'Hongju Seedless'. Acidity was the lowest in 'My Heart' at 0.39%, followed by 'IFG-6', 'Stella' and 'Hongju Seedless'. As for the coloring, in the case of 'My Heart', the skin color did not change to red even after the harvest season, therefore the grapes were irregularly colored, so it was judged that the development of cultivation technology to enhance the coloring was necessary.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.483-489
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• 2013

The abnormal seedlings, a common physiological anomalies, emerged during embryo rescue severely restricted grape breeding. To enhance the efficiency of the seedless grape breeding by reducing the production of abnormal seedlings in the course of embryo rescue, we investigated the effects of genotype, media type, embryo style, pre-chilling on the deformity rate of the abnormal seedlings during embryo rescue. The abnormal seedlings were firstly classified into seven categories based on their morphology. Our results indicated that the emergence of abnormal seedlings was highly dependent on the female parent genotype. Polyembryony was advantageous to diminish the number of abnormal plantlets and the germination rate of embryo was 100%. We also found that pre-chilling treatment could reduce the number of abnormal plantlets and promote the embryo germination. The abnormal plantlets were reduced significantly by the addition of $ZnSO_4$ $10{\mu}mol{\cdot}L^{-1}$ or mashed-banana $500mg{\cdot}L^{-1}$ to either embryo development or germination media. Transferring the abnormal seedlings onto the suitable fresh media in 4 weeks after embryo germination provided an effective way to transform them into normal seedlings.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.45-56
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• 2019

As a result of analyzing the quality of imported grapes during the 2018 season, the hardness of the grape berry was found to be 10 N or less in total. In the case of Chilean grapes, the soluble solids tended to be lower as imports and distribution periods were delayed. The berry weight was the largest at 14.4 - 14.8 g for the 'Red Globe', 7.1 - 7.4 g for the 'Thompson Seedless' and 6.0 - 7.0 g for the 'Crimson Seedless'. The 'Crimson Seedless' grapes imported from Chile, which had a high berry shatter rate, had a shorter pedicel length, pad width and brush length than that of the other 2 varieties. Regardless of the grape varieties, the weight loss during the distribution at room temperature ($25^{\circ}C$) increased rapidly as the import season was delayed. Additionally, it was found that the later the distribution seasons, a higher stem browning index was observed regardless of the variety. The 'Thompson Seedless' was revealed to be more susceptible to browning than that of the other varieties. The shrinkage of the stem and the pedicel browning progressed within a short time during shelf-life as the distribution time was delayed. The incidence of berry decay of the imported grapes tended to increase with the progression of the distribution period. In the fruits distributed on April, except for the 'Crimson Seedless', the grapes were rapidly corrupted in the second half of the distribution. The 'Red Globe' grapes completely lost marketability due to a berry decay of 26.1% and 69.9% at 9 and 12 days after shelf-life, respectively.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.135-140
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• 2013

This experiment was conducted to find the effects of a $GA_3$ and thidiazuron (TDZ) on seedless rate, harvest time, fruit cracking and fruit quality in 'Kyoho' grapes over two years from 2008 to 2009. In 2008, fruit clusters were dip treated with $GA_3$ $25.0mg{\cdot}L^{-1}$ twice at full bloom (FB) and 14 days after full bloom (DAFB) in a combination with TDZ 0 or $2.5mg{\cdot}L^{-1}$. Berry seedless rate and berry enlargement were slightly improved only when TDZ was added to the second $GA_3$ treatment at 14 DAFB, compared to $GA_3$ + TDZ treatments at both FB and 14 DAFB. However, berry cracking rate was significantly increased by any plant growth regulator (PGR) treatments compared to non treatment. In 2009, $GA_3$ at $12.5mg{\cdot}L^{-1}$ and $25.0mg{\cdot}L^{-1}$ was dip treated twice at FB and 14 DAFB while TDZ $2.5mg{\cdot}L^{-1}$ was treated only at 14 DAFB. Berry cracking rate was depended on the concentration of $GA_3$ applied. The higher concentration at $25.0mg{\cdot}L^{-1}$ significantly increased berry cracking rate while the lower concentration at $12.5mg{\cdot}L^{-1}$ had no effect. Also, the addition of TDZ to $GA_3$ $25.0mg{\cdot}L^{-1}$ at 14 DAFB, substantially decreased the cracking rate to the level of untreated control. Although all PGR treatments advanced fruit maturity, the most significant advance occurred when TDZ was added to $GA_3$ $12.5mg{\cdot}L^{-1}$ only at the second dip. Considering the overall aspects related to fruit maturity and quality, we concluded that the double applications of $12.5mg{\cdot}L^{-1}$ $GA_3$ at FB and 14 DAFB with addition of $2.5mg{\cdot}L^{-1}$ TDZ only at 14 DAFB was appropriate to produce about 400-500 g size of seedless 'Kyoho' grape cluster having 35-40 berries.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.932-940
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• 2015

One of the main factors restricting production of triploid seedless watermelon is poor germination due to weak embryos, thick seed coats, and larger air spaces. This study was carried out to investigate the priming effects of different concentrations of chemicals, including hydrogen peroxide ($H_2O_2$), fusicoccin, and gibberellic acid (GA) on germination and seedling uniformity of triploid watermelon (Citrullus lanatus). Three commercial triploid cultivars, Seedless Plus, Sinus, and Sizero, were pretreated with water and different levels of $H_2O_2$ (2 and 4%), fusicoccin (FC: 1, 5, and $10{\mu}M$), and GA (1, 5, and $10{\mu}M$). The present findings helped to find optimal priming conditions for improving germination of triploid watermelon. Treatment with $5{\mu}M$ GA and hydropriming helped to break seed dormancy, enhancing the final germination percentages in all triploid cultivars and increasing the germination index in Sizero. These seed-priming treatments could be used on large scale for industrial applications. Moreover, hydropriming provides a simple, effective, and costless method to improve seed germination and seedling vigor of Sinus and Sizero varieties.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.656-664
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• 2015

To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.186-195
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• 2015

This research was conducted to investigate effect the plant growth regulators (PGRs) on the characteristics of fruit and flesh softening, using GA3 and thidiazuron (TDZ) treatments in 'Heukboseok' grapes. The total yield obtained under PGR treatment was 88.3% lower than the target production when a single treatment with $GA_3$ of low concentrations was used, but the expected yield was recovered by combined treatment with TDZ and $GA_3$. When harvested on the basis of color, the harvest rate up to 100 days after full bloom (DAFB) was low with the $GA_3$ single treatment, but was increased by the addition of TDZ, with the second TDZ mixed treatment being particularly effective. The soluble solids content in the PGR-treated samples demonstrated no significant changes after 90 DAFB, while the acidity content decreased rapidly starting from 90 DAFB. Measured on the basis of sugar and acidity content, maturity was reached much earlier in treated fruit than in the non-treated fruit. Firmness was maintained at a higher level until the final harvest time after PGR treatment compared to untreated grapes according to epidermis thickness and flesh density increase to activity cell division and expansion by $GA_3$ and TDZ. In particular, the fruit quality was improved based on the delay of softening in primary and secondary treatments of $25mg{\cdot}L^{-1}\;GA_3+2.5mg{\cdot}L^{-1}$ TDZ. The production of seedless fruit was difficult, even with the inclusion of TDZ, reaching the highest seedless rate of only 65.5%. Fruit cracking was rare, occurring at a rate of about 0.0~0.9% in all treatments. Accordingly, 'Heukboseok' grapes should be harvested within 100 days after full bloom (DBFB) before a rapid decrease of firmness, conferred by primary and secondary treatments with $25mg{\cdot}L^{-1}\;GA_3+2.5mg{\cdot}L^{-1}$ TDZ.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.497-502
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• 1997

A seed pelleting technique was developed for easy handling of small sesame seeds (Chinbaeckkae) and for direct seeding in field. The mixture of pelleting material, binder(sodium alginate) and seeds were dropped in 100mM CaCl$_2$ solution. Charcoal was appeared as a best material among all to make pellets with the characters of hardness, breakdown, destruction rate and germination percentage. Zeolite formed the hardest pellet seeds among the materials and 1~3 seeds contained in a pellet on the treatment of 87g of sesame seeds mixed in 1$\ell$ CaCl$_2$ solution was estimated optimum rate of seed mixure with few appearance of seedless pellet. The moisture absorption rate was greater in the order of peat＋charcoal > peat > charcoal > zeolite. Germination percentage of pelleted seeds with charcoal was the best and similar to that of common non-treated seeds. Germination percentage of pelleted seeds by sowing depth of exposing a quarter of pellet seeds on the surface of vermiculite germination test box and were 92％ in charcoal treatment and was the best among all released materials.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.535-541
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• 1996

A seed pelleting technique was developed for easy handling of small tobacco seeds (variety, NC82) and for direct seeding in temperary planting bed or in field. The mixture of pelleting material, binder and seeds were moulded in cylindrical holes sized 2 mm diameter and 2 mm height in a plastic plate. Bentonite and cellulose powder were good materials to make pellets with CMC as binder, and bentonite formed the hardest pelleted seeds among the materials. The number of the pelleted seeds made with the same weight of the materials was different with materials used and the number of seeds contained in a pelleted seed could be controlled by mixture ratio of materials and seeds. The seedless pellets ranged 6.9 to 16.0% at the ratio of pelleting material and seed for 2~3 seeds in a pellet. The moisture absorption rate at 100% RH and $25^{\circ}C$ was greater in the order of clay < bentonite < cellulose. Germination rates of pelleted seeds with bentonite and cellulose were similar to that of usual seed, but it was significantly lower with clay pelleted seeds.