JAEA-Review 2010-065

Ion Beam Irradiation with Rice Seeds for the Mutation
Breeding Project of the Forum for Nuclear Cooperationin Asia (FNCA)a)a)a)a)A. Tanaka , S. Nozawa , Y. Hase , I. Narumi , H. Ishikawaa)Radiation-Applied Biology Division, QuBS, JAEA,

1. Introduction
For the spread of radiation application and developmentof ion beam breeding technique, ion beams have beenutilized under the Mutation Breeding Project of the Forumfor Nuclear Cooperation in Asia (FNCA) of MEXT
(Ministry of Education, Culture, Sports, Science andTechnology). This project contributes to increase foodproduction and to improve food quality in Asia, bydeveloping new mutant varieties with disease resistance,
insect resistance, and drought tolerance of important crops,
such as rice, bananas, orchids, sorghum, and soybeans, byusing ionizing radiation.
As the Sub-Project on
Composition or Quality in Rice, utilization of ion beams has
been started in 2009. Eight participant countries, i.e.,
Bangladesh, China, Indonesia, Korea, Malaysia, Philippines,
Thailand and Vietnam joined the ion beam irradiation withrice seeds.

and A. Koikeb)

Nuclear Safety Research Association

good quality in term of low amylose content or high protein
content and other characters. For this purpose, ion beamirradiation should be effective but not too much, in order not
to induce bad characters or abnormalities of a mutant plant.
To determine the optimal doses for mutation induction is thefirst and most important work for mutation breeding.
Radiation sensitivity strongly depends on not only
sub-species (indica or japonica) but also their cultivars.
Therefore, precise data should be necessary for each cultivar.
The growth and survival curves have been obtained toevaluate the best dose for mutation induction (Fig. 2). For
example, in the case of indica cv. Ashal, proper dose would
be 30-40 Gy because these doses caused the shoulder end of
the survival curve that would be proper to induce mutants
without bad characters from our sufficient experiences.
Several countries have already obtained survival curves andidentified the optimal doses for mutation induction. The
other countries will continue sensitivity tests anddetermination of the optimal doses for mutagenization.
Seedling height (cm)

Seedling height (cm)2. Materials & Methods
In order to obtain fruitful results, the clear and common
protocol for all participant countries was firstly drawn up as
shown in Fig. 1.

b)b)Survival %

25100

2080

1560

1040

5200Survival % of seedlings

3-05

00

10204060

80

100

120

160

200

Irradiation dose (Gy)Fig. 2 The growth and survival data of indica cv.
Ashal seeds irradiated with carbon ions (courtesy ofDr. Md. Lokman Hakim, Bangladesh).

Fig. 1

Outline of protocol for the ion beam irradiation.

In general, hulled dry seeds of a rice cultivar (cv.) ofparticipant country was irradiated with 320 MeV carbon ion
beams in TIARA. About 70-100 seeds were set on a50 mm petri-dish and irradiated within 30-90 seconds forany doses ranged from 10 to 200 Gy. After irradiation,
seeds were rightly sent back to the participant countries andgrown to obtain survival curves and the offspring.
3. Results and Discussion
The purpose of rice breeding should be high yield and- 61 -Fig. 3 Three-week-old plant of japonica cv. Ilpum
irradiated with carbon ions (courtesy of Dr. Si-YongKang, Korea).