Effects of the total dose and duration of γ-irradiation on the growth responses and induced SNPs of a Cymbidium hybrid

Abstract

Purpose: Ionizing radiation has been used for developing new cultivars of diverse plant species, including Cymbidium orchid species. The effects of the total dose on mutation induction have been investigated; however, there is relatively little research on the influence of the dose rate or irradiation duration.

Materials and methods: Thus, we analyzed the effects of the total dose and irradiation duration on the growth of Cymbidium hybrid RB001 protocorm-like bodies (PLBs). We completed a genotyping-by-sequencing analysis to compare the induced SNPs among five γ-irradiated populations with similar growth responses (LD₅₀) to γ-rays.

Results: The optimal time to assess the effects of the γ-irradiation was at 6 months after the treatment. On the basis of the survival rate of γ-irradiated PLBs, the optimal doses (LD₅₀) for each irradiation duration were estimated: 1 h, 16.1 Gy; 4 h, 23.6 Gy; 8 h, 37.9 Gy; 16 h, 37.9 Gy; and 24 h, 40.0 Gy. The estimated optimal doses were duration-dependent at irradiation durations shorter than 8 h, but not at irradiation durations exceeding 8 h. A SNP comparison revealed a lack of significant differences among the mutations induced by γ-irradiations.

Conclusions: These results indicate the irradiation duration affects PLB growth in response to γ-rays. Moreover, the mutations induced by a short-term treatment may be similar to those induced by a treatment over a longer period.

Keywords:

• γ-ray
• total dose
• irradiation duration
• dose rate
• Cymbidium
• SNP

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by grants from the Nuclear R&D Program of the Ministry of Science and ICT and the research program of KAERI, Republic of Korea.

Notes on contributors

Sang Hoon Kim

Sang Hoon Kim, is a senior researcher of Korea Atomic Energy Research Institute. He is working on mutation breeding with horticultural crops.

Yeong Deuk Jo

Yeong Deuk Jo, is a senior researcher of Korea Atomic Energy Research Institute. He is working on mutation breeding with vegetable crops.

Jaihyunk Ryu

Jaihyunk Ryu, is a senior researcher of Korea Atomic Energy Research Institute. He is working on mutation breeding with medicinal plants.

Min Jeong Hong

Min Jeong Hong, is a senior researcher of Korea Atomic Energy Research Institute. She is working on mutation breeding with wheat and Arabidopsis.

Byoung-Cheorl Kang

Byoung-Cheorl Kang, is a professor of Seoul National University. He is working on pepper breeding and genomics.

Jin-Baek Kim

Jin-Baek Kim, is a principal researcher and the head of Radiation Breeding Research Team, Korea Atomic Energy Research Institute.