JAEA-Review 2011-043

3-39

Ion Beam Irradiation on Rice Seeds for the Mutation
Breeding Project of the Forum for Nuclear
Cooperation in Asia (FNCA)a)a)a)a)A. Tanaka , S. Nozawa , Y. Hase , I. Narumi , H. Ishikawaa)b)and A. Koikeb)

Life Science and Biotechnology Division, QuBS, JAEA,b)
Nuclear Safety Research Association

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 resistant to disease,insects, and environment, or higher yields and quality ofimportant crops such as soybean, sorghum, orchid andbanana, and so on. As the Sub-Project on Composition orQuality in Rice, utilization of ion beam has been started in2009. Eight participant countries, i.e., Bangladesh, China,Indonesia, Korea, Malaysia, The Philippines, Thailand andVietnam joined the ion beam irradiation with rice seeds.
2. Materials and Methods
In general, hulled dry seeds of a rice cultivar (cv.) ofparticipant countries were irradiated with 320 MeV carbon
ion beam in TIARA 1). After irradiation, seeds were rightly
sent back to the participant countries and grown to obtain
the offspring.
At the FNCA workshop on Mutation Breeding held in
Philippines in November 2010, we have deeply discussed
the appropriate population size for irradiation treatment andsuggested that the minimal number of initial cells to beirradiated is at least 5,000 in order to obtain enough mutants.
The protocol for selection of seeds after irradiation was also
discussed and it was suggested to harvest 5 seeds from 5
panicles from each M1 plant as shown in Fig. 1.

3. Results and Discussion
In 2010, most of participant countries were able to decide
the best doses for mutation induction and some countries
have also carried out harvesting of M2-M3 plants and theirscreening. For example, in the Philippines, initial result
showed that the best dose was found to be 20 Gy and thelethal doses were 160 and 200 Gy. In the M1 generation,plant height, days to heading, number of productive tillers,
number of seeds per panicle, and sterility were affected by
the irradiation. However, no differences were obtained on
the panicle length and 100 seed-weight. In Vietnam,
mutation has been observed in plant height, grain weight,
maturity or sterility in the M2 generation of both Khang danand Bac thom varieties. In the M3 generation, someinteresting characteristics related to yield were shown andchosen as for grain weight, short grow duration, tolerant todisease, and semi-dwarf plant (Fig. 2). In Bangladesh, theM3 progenies derived from irradiated seeds of a local salt
tolerant cultivar-Ashfal were evaluated. The M3 progenies
derived from either 40 Gy or 200 Gy included
photoinsensitive mutation. This progenies also included
early mature and high yield characters (Fig. 3).

Fig. 2 Khang dan variety (left), and its semi-dwarf
mutant that is tolerant against lodging (right).

Fig. 3 BRRI dhan-29 variety (right), and its mutant linewith early mature and high yield (left).

Fig. 1

Protocol for mutation line establishment in rice.

Reference
1) A. Tanaka et al., JAEA Takasaki Ann. Rep. 2009 (2011)61.

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