• Journal of Korean Society of Forest Science
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• v.75 no.1
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• pp.38-45
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• 1986

This study was designed to investigate the karyotype analysis of Juniperus chinensis and its seven varieties, and P. densiflora and P. densiflora for. multicaulis. Following results were obtained. 1. Three varieties, J. chinensis v. kaizuka, J. chinensis v. aureo-variegata and J. chinensis v. procumbens are turned out as tetraploids. 2. Varieties having many long chromosomes and long mean relative length of chromosomes are J. chinensis and J. chinensis v. aureo-globosa, while varieties having short chromosomes are J. chinensis v. horizontalis and J. chinensis v. globosa. 3. Varieties with high mean ratio of long arm length to short arm are J. chinensis v. globosa and J. chinensis v. kaizuka, while a variety with the low mean ratio is J. chinensis v. aureo-globosa. 4. When chromosomes are arranged according to the total length, the most similar variety with J. chinensis was J. chinensis v. sargentii, J. chinensis v. horizontalis, J. chinensis v. globosa and J. chinensis v. aureo-globosa, while the least similar one was J. chinensis v. procumbens. 5. Pinus densiflora for. multicaulis has shorter mean relative length of chromosome than P. densiflora, while the arm ratio of the former is higher than the latter. 6. When chromosomes are arranged according to the total length, six chromosomes showed the same order between the two varieties. 7. P. densiflora for. multicaulis has many chromosomes with secondary constriction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.104-111
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• 1997

Since seeds of Italian ryegrass should be imported every year, it is necessary to investigate the prossible production of seeds in Italian ryegrass field after rice. Seven Italian ryegrass varieties were planted on October 8, 1986 at National Honam Crop Experiment Station at Iksan and clippings were made on April 10 and April 30 in 1987. Headings of K-11 and T.N.T were earlier than those of Tetrone and Bettina. For all varieties tested, heading date was delayed and 1,000 grain weight was decreased linearly as the clipping was made later. Length, width and thickness of a grain were reduced by clipping and later clipping, while tetraploid varieties produced larger grains than diploid varieties. The germination percentage and germination speed at $25^{\circ}C$ were higher than at 15$^{\circ}C$. The final germination percentage was lower at the later clippings and was higher at 15$^{\circ}C$, and earlier varieties showed higher germination percentage. Uniformity of germination was greater at $25^{\circ}C$ and was decreased as the clipping was made later, and the eariler varieties such as K-11 were germinated more uniformly. Average number of days to germination was longer at 15$^{\circ}C$ than at $25^{\circ}C$ and was longer at later clipping. The germination percentage was decreased linearly as the heading was delayed, while it increased linearly as the 1,000 grain weight was increased.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.86-93
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• 1997

In order to induce somatic embryogenesis from the stem explants and anther of Kalanchoe daigremontiana, the explants were cultured on MS medium supplemented with auxin (2,4-D, IAA, NAA) and/or cytokinin (BAP) for 8 weeks. Callus from explants was induced most efficiently on MS medium containing. 2.0mg/L NAA and 0.2mg/L BAP. Somatic embryogenesis in stem callus was formed by transfering embryogenic callus from induction media containing growth regulators to medium without growth regulators and then to the medium containing auxin and cytokinin (0.1 mg/L IAA and 1.0mg/L BAP). Callus formation occurred actively in the anthers at early uninucleate stage, and by low temperature pretreatment at $4^{\circ}C$ for 3days. Somatic embryogenesis from the anther callus was induced on MS medium containing 1.0mg/L NAA and 1.0mg/L BAP, 2.0mg/L NAA and 0.2mg/L BAP. The tetraploid of 5.4% was obtained among plants regenerated from anthers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.3
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• pp.171-176
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• 2006

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass(Lolium multiflorum Lam.) in Grassland and Forages Division, National Livestock Research Institute, RDA, Suwon from 1987 to 2005. New variety, Kowinner as a tetraploid variety was dark green in leaf color and growth habit in autumn and early spring was semi-prostrate and medium, respectively Kowinner as a medium or late-heading variety was 19th May in heading date. Flag leaf length of Kowinner was 29 cm that was the same as control variety, Hwasan 101. Length of longest stem and plant length of Kowinner were 70 cm and 97 cm that was longer 3 cm than those of Hwasan 101, respectively. Stem width of Kowinner was thicker than that of Hwasan 101. Expecially, Kowinner was very good in regrowth. Cold tolerance of Kowinner was slightly weaker than that of Hwasan 101 and slightly stronger than that of Florida 80. Dry matter(DM) yield(12,884 kg/ha) of Kowinner was 8% more than that of Hwasan 101. In vitro dry matter digestibility and total digestible nutrient(TDN) of Kowinner were 76.2 and 63.3% that was 1.6 and 0.4% lower than those of Hwasan 101, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.1
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• pp.79-83
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• 1985

This experiment was carried out in order to determine the optimum harvesting time of tetraploid Italian ryegrass. Moisture content, 1000-seed weight, germination and seed shattering were investigated at six harvesting times after anthesis in 1984 at Suweon. The results are summarized as follows; 1. Seed moisture content was slowly decreased until 24 days and fastly decreased from 24 days after anthesis. The daily mean moisture loss during the ripening period was about 1.5 percentage. 2. The maximum 1000-seed weight was reached at 24 days after anthesis and 1000-seed weight of Waseking was heavier than that of Giant. 3. Shattering began at 17-20 days after anthesis and thereafter rapidly increased. 4. Germination was 50% at 10 days after anthesis and maximum germination was reached at 24 days. 5. Considering germination, 1000-seed weight and shattering, the optimum harvest time was 24 to 27 days after anthesis. At this time, moisture content was 55.0 to 43.5 percent and two to five seeds per ten spikes were shed by shaking at the vertical point.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.215-220
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• 1994

Pollen-derived embryos cultured on the hormone-free medium showed a low germination frequency (12.5%) and poor growth response after germination. The greatest frequency of germination (81.3%) was obtained from the embryos cultured on medium with 0.3mg/L GA$_3$.The greatest frequency of generation (81.3) was obtained from embryos cultured on medium with 0.3mg/L GA$_3$. The embryos precultured for 20 days on medium with 0.3mg/L GA$_3$were transferred to the medium with various combination of hormones such as IAA, kinetin, zeatin, 6-benzylaminopurin (BA) and Gh$_3$. The germination frequency of cotyledonary stage embryos showed above 72% on media with all of the hormonal combinations, but the embryos germinated on medium with 2mg/L BA or 0.1mg/L kinetin and 0.3mg/L GA$_3$ developed more vigorously into plantlets than those of other hormonal combinations. Torpedo-stage embryos cultured on medium with 0.3 mg/L Gh$_3$ were pretreated for 8 weeks at 2-week intervals at 4$^{\circ}C$, The germination frequency of the cold-preheated embryos increased with the increment of pretreatment period from 2 to 8 weeks. The greatest frequency of germination (73.3%) was obtained from the embryos pretreated for 8 weeks at 4$^{\circ}C$. The chromosomes of the root-tip cells of W plane grown for 40 days after germination were observed. Most of the regenerated plants were haploid (55.8%) or diploid (315%), but triploid (1.3%), tetraploid (5.2%), or aneuploid (6.5%) were also detected among them.

• Journal of Plant Biotechnology
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• v.47 no.2
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• pp.131-140
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• 2020

Solanum stoloniferum, one of the wild tetraploid Solanum species belonging to the Solanaceae family, is an excellent resource for potato breeding owing to its resistance to several important pathogens. However, the sexual hybridization of S. stoloniferum with S. tuberosum (potato) is hampered due to the sexual incompatibility between the two species. To overcome this and introgress the various novel traits of S. stoloniferum in cultivated potatoes, cell fusion can be performed. The identification of the fusion products is crucial and can be achieved with the aid of molecular markers. In this study, the chloroplast genome sequence of S. stoloniferum was obtained by next-generation sequencing technology, and compared with that of six other Solanum species to identify S. stoloniferum-specific molecular markers. The length of the complete chloroplast genome of S. stoloniferum was found to be 155,567 bp. The structural organization of the chloroplast genome of S. stoloniferum was similar to that of the six other Solanum species studied. Phylogenetic analysis of S. stoloniferum with nine other Solanaceae family members revealed that S. stoloniferum was most closely related to S. berthaultii. Additional comparison of the complete chloroplast genome sequence of S. stoloniferum with that of five Solanum species revealed the presence of six InDels and 39 SNPs specific to S. stoloniferum. Based on these InDels and SNPs, four PCR-based markers were developed to differentiate S. stoloniferum from other Solanum species. These markers will facilitate the selection of fusion products and accelerate potato breeding using S. stoloniferum.

• Journal of Plant Biotechnology
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• v.47 no.2
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• pp.141-149
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• 2020

Solanum hougasii, one of the wild Solanum species, has been widely used in potato breeding since it exhibits excellent resistance to diverse important pathogens. S. hougasii can be directly crossed with the cultivated tetraploid potato (S. tuberosum) owing to its EBN (Endosperm Balanced Number) value of 4, which is same as that of S. tuberosum although it is an allohexaploid. In this study, the complete chloroplast genome sequence of S. hougasii was obtained by next-generation sequencing technology, and compared with that of the chloroplast genome of seven other Solanum species to identify S. hougasii-specific PCR markers. The length of the complete chloroplast genome of S. hougasii was 155,549 bp. The structural organization of the chloroplast genome in S. hougasii was found to be similar to that of seven other Solanum species studied. Phylogenetic analysis of S. hougasii with ten other Solanaceae family members revealed that S. hougasii was most closely related to S. stoloniferum, followed by S. berthaultii, and S. tuberosum. Additional comparison of the chloroplast genome sequence with that of five other Solanum species revealed five InDels and 43 SNPs specific to S. hougasii. Based on these SNPs, four PCR-based markers were developed for the differentiation of S. hougasii from other Solanum species. The results obtained in this study will aid in exploring the evolutionary and breeding aspects of Solanum species.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.17-21
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• 2011

Korean bennudagrass collections showed diverse genetic variations in their morphology, growth habit, and cytological aspects. Chromosome number and nuclear DNA content of the bennudagrasses indicated a ploidy level ranging from triploid (2n=3x) to hexaploid (2n=6x). In this study, we investigated the different responses of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase) and cell membrane stability of those bennudagrass cytotypes to lower temperature and shorter day length, which meets a dormant induction in Korea. All the antioxidant enzymes were found to be higher during dormant stage, while the heme-containing catalase which converts hydrogen peroxide ($H_2O_2$) to water and oxygen molecules was activated before dormant initiation in the three cytotypes except for hexaploid bennudagrass. The triploid and tetraploid which exhibited relatively finer leaves and a rapid establishment speed were found to show increased activities of superoxide dismutase and peroxidase enzyme. The malondialdehyde(MDA) which is a product of lipid peroxidation in the cell membrane damaged by the hydroxyl radical was increased in all cytotypes as temperature declined, and tri- and tetraploids which had more protective antioxidant enzymes demonstrated a significantly lower MDA production. Similarly electrolyte leakage was higher in penta- and hexaploidy, seemingly more damage to cell membrane when low temperature was implemented. Results indicated that antioxidant responses of different cytotypes were genetically specific, which needs to be investigated the relevance with the low temperature tolerance in the bermudagrass further at the molecular level.

• Korean Journal of Plant Taxonomy
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• v.42 no.4
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• pp.307-315
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• 2012

Somatic chromosome numbers for 10 taxa and karyotypes analysis for 6 taxa of Korean Vicia were investigated. Somatic chromosome numbers of treated taxa were 2n = 12, 14 or 24 and therefore they proved to be diploid or tetraploid with basic chromosome numbers of x = 6 or 7. The chromosome number of V. hirticalycina (2n = 2x = 12) was reported for the first time in this study. The chromosome numbers of nine taxa were the same as in previous studies; V. angustifolia (2n = 2x = 12), V. cracca (2n = 4x = 24), V. hirsuta (2n = 2x = 14), V. tetrasperma (2n = 2x = 14 + 2B), V. amurensis (2n = 2x = 12), V. chosenensis (2n = 2x = 12, 12 + 2B), V. unijuga (2n = 4x = 24), V. unijuga f. minor (2n = 4x = 24), V. venosa var. cuspidata (2n = 4x = 24). The karyotypes of V. cracca, V. amurensis, V. hirticalycina, V. unijuga, V. unijuga f. minor, V. venosa var. cuspidata were observed as 2 m + 8 sm + 2 st, 2 m + 2 sm + 2 st, 3 m + 1 sm + 2 st, 4 m + 6 sm + 2 st, 4 m + 6 sm + 2 st, 4 m + 8 sm, respectively.