• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.128-135
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• 2016

This study examined radiation damage and the optimal gamma-ray dose for mutation breeding in oat (Avena sativa L. cv. Samhan). The seed germination rate decreased as the dose increased over 500 Gy. The median lethal dose (LD₅₀) was approximately 392 Gy. The median reduction dose (RD₅₀) for plant height, tiller number, root length, and flash weight was 411, 403, 394, and 411 Gy, respectively. The optimal dose of gamma irradiation for inducing oat mutation appears to be in the range 300-400 Gy. We performed the comet assay to observe nuclear DNA damage induced by gamma-ray irradiation. This assay showed a clear difference with gamma-ray treatments. DNA damage increased temporarily 7 days after treatment depending on the dose, while no significant difference was identified in response to 300 Gy 30 days after the gamma-ray treatments. The growth characteristics of the M₂ generation decreased as the dose increased over 400 Gy.

• Journal of Radiation Industry
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• v.10 no.4
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• pp.211-217
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• 2016

We examined damages from gamma-irradiaion and determined the optimal gamma-ray dose for mutation breeding in lentil (Lens culinaris L.) bean. Four individual lines (L-C, L-2, L-8 and L-9), that have remarkable adaptability in South Korea were gamma-irradiated at doses of 50, 70, 100, 200, 300, 400, and 500 Gy. The germination rate of seed decreased as the dose increased over 50 Gy in all lines. However, $LD_{50}$ and $RD_{50}$ were different among lines. The median lethal doses($LD_{50}$) were approximately 127 (L-C), 74 (L-2), 95 (L-8), and 144 (L-9) Gy. The median reduction doses($RD_{50}$) for plant height, number of leaves, root length, and flash weight were 156, 176, 150, and 180 Gy for L-C, 253, 198, 127, and 142 Gy for L-2, 188, 175, 200, and 190 Gy for L-8, and 162, 210, 224, and 184 for L-9, respectively. The growth characteristics of the $M_1$ generation decreased as the dose increased over 70 Gy. The optimal doses of gamma irradiation for mutation breeding of lentil were determined to be 70 Gy (L-2, L-8) and 100 Gy (L-C, L-9). We performed the comet assay to observe nuclear DNA damage induced by gamma-irradiation. In comet assay, a clear difference was identified over 100 Gy treatments. With increasing doses of gamma-ray in the range of 50 to 500 Gy, the rate of head DNA was decreased significantly from 97.5% to 81.6%. Tail length was consecutively increased from $1.9{\mu}m$ to $17.4{\mu}m$. Our result provides basic information for construction of mutant pools in lentils.

• Korean Journal of Medicinal Crop Science
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• v.28 no.5
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• pp.339-346
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• 2020

Background: Cnidium officinale Makino have been used in traditional medicine in Northeast Asia. Although gamma-ray mutagenesis has been used to develop breeding resources with novel characteristics, research on the radiation sensitivity of C. officinale Makino is limited. Hence, the optimal gamma-ray dosage for mutation breeding in C. officinale Makino was investigated. Methods and Results: Seedstocks were exposed to doses of gamma rays (5 Gy - 50 Gy), and subsequently planted in a greenhouse. After 30 days of sowing, the survival rates and growth decreased rapidly at doses above 20 Gy, while all individuals died at 50 Gy. The median lethal dose (LD₅₀) was 25.65 Gy, and the median reduction doses (RD₅₀) for plant height, number of stems, and fresh weight were 12.81, 9.32, and 23.26 Gy, respectively. Post-irradiation levels of malondialdehyde (MDA), peroxidase (POD), and chlorophyll in the aerial parts of the plant were quantified using spectrophotometry. Relative to the controls, the levels of MDA and POD increased, while the level of chlorophyll decreased at doses ≥ 10 Gy, indicating cellular damage. Conclusions: A dose of 20 Gy was found to be optimal for mutation breeding in C. officinale Makino.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.27-27
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• 2021

Yacon [Samallanthus sonchifolius (Poepp. & Endl.) H. Robinson], a member of Compositae plants, has sweet taste and crisp texture. Unlike other Andean root crops such as potato and sweet potato, the cultivation area of yacon has increased recently, since it is known to have large content of fructooligosaccharides (FOS). Since there are no yacon varieties bred in Korea, we have been trying to create new genetic resources using gamma-ray. The optimal gamma-ray dosage for mutation breeding in yacon was investigated. Crown bud and green bud of yacon were exposed to doses of gamma rays from 20 Gy to 80 Gy, and subsequently planted in a greenhouse. After 50 days of sowing, the survival rates and growth decreased rapidly at doses above 40 Gy, while all of crown bud individuals died above 60 Gy. The median lethal dose (LD50) of crown bud and green bud was 22.4 and 36.6 Gy, and the median reduction doses (RD50) for plant height, fresh weights, and tuberous root weight were 20-40 Gy, respectively. A dose of 20-40 Gy was found to be optimal for mutation breeding in yacon. Considering the growth factors, the optimum doses were determined to be within the range of 20-40 Gy for the selection of useful mutant lines. M2-M3 mutant lines were obtained from 20-60 Gy gamma-ray-irradiated M1 plants through clonal propagation. These mutant lines will be used for the development of a new variety of yacon plant with high FOS and no crack tuberous root.