1. Bangladesh

High Yielding mutants with shorter life cycle selected in rice
irradiated with carbon ion beam
A. N. K. Mamun, A. K. Azad 1, M. H. Kabir, P. K. Roy, M. R. Islam and M. T. Jahan,
M. A. Azam1, M. L. Hakim, & G. Ahmed
Biotechnology and Genetic Engineering Division, Institute of Food and Radiation Biology,
Atomic Energy Research Establishment, Bangladesh Atomic Energy Commission,
1

Plant Breeding Division, Bangladesh Institute of Nuclear Agriculture, Bangladesh

1.1 Summary
To investigate the possibility of induced fixed and stable mutants in M 1 generation of rice in which,
one hundred and fifty seeds of the highly photoperiod sensitive and tall indica type rice cv. Ashfal
and popular variety BRRI dhan29 were irradiated with different doses of carbon ion beams from theRadiation Applied Biology Division, Quantum Beam Science Division, Japan Atomic Energy Agency,
Japan. In case of BRRI dhan29 and Mutant of BRRI dhan29, it was grown during Boro season, 2012
and in the case of Ashfal M 1 was grown during long day length at Boro (December-May) season andM2 during short day length at Aman season (July–December) in 2009 whilst M 3 once again grown
during Boro season in 2010. Nine M 1 hills in which, 2 from each of 40, 120 and 160Gy, and 1 fromeach of 60, 80 and 200 Gy were headed even under long day in Boro season despite none of theparent plants of Ashfal headed during Boro season. Of the heading of M 1 plants that had the plantheight as the parent that could not produce any seed. Interestingly only the shorter plant height thatcapable to produced seeds. The M2 progenies took 85 days and 110 days for heading and maturity
respectively, during short days in Aman season. In contrast, the parent Ashfal headed after 7
November and matured at 152 days. In M 3 generation, the progenies bred true as in M 2 for heading,maturity and plant height. It was further confirmed that the Ashfal parent and the mutants had similar
1000-grain weight. Interestingly in case of mutant of BRRI dhan29 showed higher yield and earlymaturity compared to the parent of BRRI dhan29. Finally, it could be concluded that it is possible toinduce stable mutant(s) with photoperiod insensitive and shorter plant height and also higher yieldand early maturity traits in rice treated by 40 to 200Gy dose range of carbon ion beams in M 1 ofindiac rice cv. Ashfal and popular rice variety in Bangladesh BRRI dhan29.
Key words: rice, indica type, ion beams, mutation, photoperiod sensitivity, fixed M 1 mutant.
1.2 Introduction
Rice (Oryza sativa L.) is a short day plant (Vergara and Chang, 1985). Almost all rice cultivars
matured in a shorter time when they were grown under a short photoperiod (about 10 h) than under along photoperiod (about 14 h). The degree of photoperiod sensitivity greatly varies among cultivars.
In Bangladesh, rice is being grown in three seasons in a year; Aman season (July to December), Boroseason (December to May) and Aus season (March to June). Ashfal is a local T.aman (July to
December) cultivar being cultivated in the coastal south western part of Ban gladesh from time
immemorial. It is highly photoperiod sensitive with long duration and tall height cultivar. It is prone
to lodging but had some degree of tolerant to salinity and submergence. Its grains are medium bold
and contains 10.3% protein and 28.6% amylose (Kamruzzaman and Asaduzzaman, 2004). Ashfal-2-

cannot be grown in Boro (long day) season as it is highly photosensitive. It often becomes lodged
even in Aman season due to its tall culm which cause yield losses to a considerable extent.
Recently, ion beam irradiation has been appeared to utilized an effective means of inducing
mutations. The biological effects of ion beams have also been investigated and observed to be showna high relative biological effectiveness (RBE) in lethality, mutation and al so to transfers high energy
to the target compared to low linear energy transfer (LET) radiation such as Gamma -rays, X-rays andelectrons (Blakely,1992). It has been also demonstrated that ion beams induce mutations at highfrequency and induce novel mutants in Arabidopsis (Hase et al. 2000, Shikazono et al. 2003, Tanaka
et al. 1997, 2002). The use of ion beams for inducing mutations in rice (Oryza satva L.) breeding has
also been attempted (Hayashi et al. 2007; Hidema et al. 2003; Rakwal et al. 2008). It is generally andwidely accepted that in mutation breeding induced traits become fixed during M 2 -M4 generations(Azad et al., 2010; Hamid et al., 2006; Shamsuzzaman et al., 1998; Azam and Uddin, 1999). But it
has been reported that it is possible to isolate fixed mutants even in M 1 generation of heavy ion
irradiated sweet pepper (Honda et al., 2006).
In this study, we aimed to describe the possibility to get fixed M 1 mutant(s) with photoperiod
insensitive, short day-length and shorter plant height from local T.aman Ashfal and also to get higher
yield and early maturity from BRRI dhan29 in rice by ion beam irradiation.

1.3 Materials and Methods
Dehusked seeds of Ashfal rice and BRRI dhan29 were exposed to 26.7 MeV/n carbon ions withdifferent doses of 0, 10, 20, 40, 60, 80, 100, 120, 160 and 200 Gy in January 2009 at Japan Atomic
Energy Agency (Takasaki, Gunma, Japan). One hundred and fifty seeds were used for each
irradiation dose. The irradiated seeds were allowed to germinate in petri dishes. Seedlings weretransplanted on February 11, 2009. Single seedlings were transplanted into each hill. Spacings weremaintained between rows and hills are of 20 cm and 15 cm respectively. All plants were grown undernatural environment at the Bangladesh Institute of Nuclear Agriculture (BINA) head quarters’ farm
Mymensingh, Bangladesh. The day length at the time of heading in Boro (December to May) season
is between 12 - 13 h whilst that in Aman season (July- December) is 10 - 11 h. Fertilizers wereapplied at a rate of N-90 Kg, P-18 Kg, K-63 Kg, S-10 Kg and Zn-1.60 Kg/ha in the forms of urea,
tripple super phosphate, muriate of potash, gypsum and zinc sulphate equal ly in all plots. All
fertilizers were applied during final land preparation excluding urea. Urea was applied at three equal
installments at 7, 30 and 55 days after transplanting. Three hand weeding were made and the plots
were kept saturated with irrigation till maturity. Heights were measured randomly from ten M 1 plantsof each irradiated dose at 3 weeks after transplanting. M 2 seeds were harvested individually fromthree fertile M 1 plants at 5 months after transplanting. The M 2 seeds were spread on a seed bed on
July 16, 2009. Survived seedlings were transplanted on August 17, 2009 and they were grown during
Aman season. Number of days to heading was recorded as the number of days required from sowing
time when 50% of plants of each line headed. Days of maturity was recorded as the number of days
required from sowing time when 90% of plants of each line appeared with yellowish grains. These
two data were recorded through visual observation by visiting the plots every alternate day. Plant
heights, number of effective tillers per plant and panicle length were measured at the time of maturity
with randomly selected 5 competitive plants. M 3 seeds were harvested separately from each M 2 plant.
-3-M3 plants were grown as plant progeny during next Boro (long day) season (December 2009 to May
2010). Data were recorded as the same as described in M 2. Grain characteristics such as length (L)and width (W) of unhusked and husked grain were recorded in October 2012. The mutants derived
from 140 Gy dose were excluded previously that are not included.

1.4 Results
Seeds of Ashfal irradiated with carbon ions were grown during Boro (long day) season in 2009.
Survival rate and plant height was determined to examine the effect of carbon ion irradiation over theplant growth cycle. Survival rate of the irradiated seeds were significantly decreased at 60Gy andremains gradually at higher doses (Table 1). Seedling height also gradually decreased with theapplication of increased rate of irradiation dose. The height of the seedlings were reduced almost half
compared to unirradiated seeds and it was started at 80Gy and gradually goes to at higher doses.
Since the cultivar Ashfal is a highly photoperiod sensitive in which, none of the control plants headed
during the Boro season. However, we have found nine M 1 plants headed under the same growing
conditions (Table 1).
Table 1. Effects of carbon ion irradiation on survival rate, seedling height and heading in highly
photosensitive rice cultivar Ashfal grown in Boro season
Dose

NumberNumber ofSurvival

Seedling

NumberNumber of(Gy)of seeds

survived

rate (%)

height* (cm)of headed

fertilesown

plantsplantsplants

0

150

147

98.0

23.5 ± 0.4

0



10

150

122

81.3

23.0 ± 0.7

0



20

150

141

94.0

21.7 ± 0.4

0



40

150

121

80.7

19.2 ± 0.8

2

1

60

150

94

66.0

15.5 ± 0.2

1

0

80

150

15

10.0

13.5 ± 1.5

1

0

100

150

9

6.0

12.5 ± 0.5

0



120

150

6

4.0

11.6 ± 1.3

2

0

160

150

11

7.3

12.9 ± 1.1

2

1

200

150

3

2.0

12.3 ± 2.0

11* Mean  SE of seedling heights at 3 weeks after transplanting were shown.

It was confirmed that photoperiod sensitivity was genetically altered in the fertile M 1 plants in which,
M2 seeds were harvested from them and grown during next Aman (short day) season in 2009.
Seedlings were raised in seed bed with 301, 650 and 246 M 2 seeds which were derived from the 40,
160 and 200Gy treated with carbon ion beam respectively. Germination rate was appeared very low
which probably due to damage of soft embryo tissue caused by ion beam or the effect of seed
dormancy occurred or the effect of both. Of which 9, 126 and 18 M 2 seedlings were transplanted to
the field. The parent Ashfal headed within 122 days and matured within 152 days after sowing in thefield. In contrast, M 2 progenies derived from 40 and 200Gy doses of carbon ion beams and 200Gy
has taken almost 85 and 110 days to heading and maturity respectively. The number of effective-4-

tillers per plant was observed 13 in Ashfal whilst it ranged from 4 to 13 in M 2 progenies (Table 2).
The panicle length was found similar to Ashfal in all M 2 progenies studied. These facts suggests thatthe photoperiod insensitive phenotype of the three fertile M 1 plants was inherited to all M 2 progenies
without any segregations.
Table 2. Characteristics of M 2 progenies grown in Aman season and M 3 progenies grown in Boro season
M 2 generation
grown in aman season, 2009
Mutant line

M 3 generation
grown in boro season, 2010

Plant
height(cm)

Number ofeffective
tillers/plant

Paniclelength(cm)

Plant
Height*(cm)

Number ofeffective
tillers/plant*

Paniclelength*(cm)

RM(1)-40(C)-1-1

75

10

21

75.6 ± 1.0

10.0 ± 0.6

22.6 ± 0.8

RM(1)-40(C)-1-2

73

11

23

77.8 ± 1.7

8.2 ± 0.7

22.8 ± 0.5

RM(1)-40(C)-1-3

77

5

23

79.0 ± 0.7

9.0 ± 0.6

22.4 ± 0.5

RM(1)-40(C)-1-4

73

10

19

77.0 ± 1.8

8.4 ± 1.0

22.8 ± 0.6

RM(1)-40(C)-1-5

76

7

24

76.8 ± 2.0

9.2 ± 0.7

22.8 ± 0.2

RM(1)-40(C)-1-6

72

7

21

74.0 ± 1.3

9.0 ± 0.8

22.8 ± 0.5

RM(1)-40(C)-1-7

74

7

21

81.0 ± 1.7

11.8 ± 0.6

23.0 ± 1.7

RM(1)-40(C)-1-8

81

6

22







RM(1)-40(C)-1-9

91

13

28

83.4 ± 5.1

11.6 ± 1.4

26.2 ± 1.6

RM(1)-200(C)-1-1

68

13

26

70.6 ± 2.0

9.2 ± 1.1

23.0 ± 0.4

RM(1)-200(C)-1-2

64

10

22

65.9 ± 0.7

6.0± 0.7

21.6 ± 0.7

RM(1)-200(C)-1-3

68

6

23

67.4 ± 2.4

7.8 ± 0.9

23.2 ± 0.7

RM(1)-200(C)-1-4

67

8

22

69.4 ± 4.8

8.6 ± 0.9

24.6 ± 1.4

RM(1)-200(C)-1-5

66

5

22

66.0 ± 1.4

6.2 ± 0.5

22.6 ± 0.9

RM(1)-200(C)-1-6

69

8

21

67.8 ± 1.2

7.8 ± 0.6

22.4 ± 0.7

RM(1)-200(C)-1-7

61

6

20

69.8 ± 1.6

6.6

± 0.7

22.4 ± 0.5

RM(1)-200(C)-1-8

62

9

22

67.6 ± 2.0

8.6 ± 0.5

22.6 ± 0.4

RM(1)-200(C)-1-9

71

7

22

70.2 ± 0.7

7.6 ± 0.4

22.0 ± 0.4

RM(1)-200(C)-1-10

56

5

19

69.4 ± 1.6

9.8 ± 0.6

22.6 ± 0.5

RM(1)-200(C)-1-11

58

7

22

69.4 ± 1.1

7.4 ± 0.2

22.2 ± 0.5

RM(1)-200(C)-1-12

64

6

21

69.2 ± 1.2

9.6 ± 1.7

21.8 ± 0.7

RM(1)-200(C)-1-13

75

6

23

69.4 ± 1.0

11.0 ± 0.9

22.6 ± 0.2

RM(1)-200(C)-1-14

66

9

21

69.6 ± 1.0

8.8 ± 0.5

23.2 ± 0.9

RM(1)-200(C)-1-15

63

7

21

67.0 ± 0.8

8.4 ± 0.9

22.6 ± 0.8

RM(1)-200(C)-1-16

56

4

16

70.6 ± 1.9

10.6 ± 1.0

22.6 ± 0.7

RM(1)-200(C)-1-17

61

8

21

65.0 ± 1.5

10.2

± 0.8

22.8 ± 0.5

RM(1)-200(C)-1-18

48

4

20

70.6 ± 2.0

9.2 ± 1.1

23.0 ± 0.4

Ashfal (parent)

148

13

24







*Mean  SE of 5 plants, RM indicates Rice Mutant; 40(C) and 200 (C) indicate irradiation with 40-5-For further confirmation of photoperiod insensitivity of mutant lines, M 3 plants derived from theeach M2 plants were grown during next Boro (long day) season in 2010. Interestingly none of theparental Ashfal was found to be headed in this season whilst all mutant lines headed almost 90 days
after sowing and matured within 119 days after sowing. Days to head ing and maturity were foundslightly longer than in the case of M 2 generation where that were grown during Aman season. It wasobserved that in M 2 generation, the plant height of mutant lines were markedly shorten than that of
Ashfal (Figure 1).The mutant lines from 40Gy were slightly shorten in plant height than that ofmutant lines from 200Gy and it was found consistent with the plant height of each mutant line
observed in M 2 generation.
Length (L) and width (W) of unhusked and husked grain and their ratio altered significantly inmutants over the parent Ashfal (Table 3). Length of unhusked and husked grain increased
significantly in all the mutants except the line RM(1)-160(C)-1. In RM(1)-160(C)-1, it was found to
decreased significantly. In contrast, width of unhusked and husked grain decreased significantly inall mutants whilst ratios of length and width (L/W) of unhusked and husked grain increased
significantly. Finally, 1000-grain weight remained unchanged in most of the mutants except 3.
Table 3 .Grain characteristics of eight mutants along with parent Ashfal

Mutant/variety

Grain length, L
(mm)

Grain
breadth(mm)

L: W

1000-Grain
weight (g)RM(1)-200 (C)-1-1

9.4 (7.0)

2.4 (2.0)

3.92 (3.50)

24.0

RM(1)-200 (C)-1-3

8.9 (7.0)

2.4 (2.0)

3.71(3.50)

23.9

RM(1)-200 (C)-1-9

9.1 (7.0)

2.3 (2.2)

3.96 (3.18)

22.5

RM(1)-200 (C)-1-10

9.4 (7.2)

2.4 (2.0)

3.92 (3.60)

24.0

RM(1)-200 (C)-1-13

8.5 (6.8)

2.3 (2.0)

3.70 (3.40)

23.8

RM(1)-200 (C)-1-17

9.3 (7.0)

2.4 (2.0)

3.88 (3.50)

24.2

RM(1)-200 (C)-1-18

9.4 (7.0)

2.4 (2.0)

3.92 (3.50)

22.6

RM(1)-160 (C)-1

7.5 (5.8)

2.8 (2.2)

2.68 (2.64)

20.5

Ashfal7.9 (6.2)

3.0 (2.6)

2.63 (2.38)

24.2

SE

0.2 (0.2)

0.1 (0.1)

0.18 (0.15)

0.4

Figures in parenthesis indicate grain characteristics from husked grain.

Preliminary yield trial with M 6 high yielding mutant lines of boro rice
Seedlings of 10 mutant lines derived from BRRI dhan29 by irradiated its seeds with carbon ion
beams in Boro season along with unirradiated BRRI dhan29 were transplanted on 22 January 2012 at
41 days after seed sowing. The experiment followed RCB design with 3 replications. Seedlings weretransplanted at 15cm distances within rows of 20cm apart. A unit plot size was 3.0m × 2.0m.
Recommended doses of fertilizers, cultural and intercultural operations were also followed as andwhen necessitated. Data on plant height, days to maturity; number of effective tiller, panicle length,
filled and unfilled grains panicle -1 and yield plot -1 were recorded. Maturity was recorded plot basis-6-while plant height, effective tiller number, panicle length, filled and unfilled grains/panicle wasrecorded from hills per plot at harvesting time. Grain yield was recorded from 1m 2 areas which waslatter converted to yield/ha at 14% moisture condition of grain. Moisture data was recorded with agrain moisture meter. Finally, the recorded data were subjected to proper statistical analyses
following the design used and are presented in Table 4.
It appears that the mutants and the check variety differed significantly for yield and yield attributing
traits except panicle length (Table 4). The mutants took 147 to 157 days to mature whilst their parent
BRRI dhan29 took 159 days. The mutant RM (2)-40 (C) -3-1-7 took the shortest period only 147
days for maturity. Filled grains was significantly the highest in the mutant RM(2) -50 ( C) -2-1-1 andit also had the highest grain yield at 14% moisture content of 8.58t/ha, which was 1.35 t/h more than
BRRI dhan29. This higher yield of this mutant was attributed to its considerably longer panicle
length and significantly higher number of filled grains/panicle (Table 4).This mutant together withthose with higher filled grains/panicle, longer panicle length, statistically as par yield and shorter
maturity period would be put into advance yield trial in the next Boro season.
Table 4. Yield and some yield attributing traits of 10 mutant lines derived from BRRI dhan29 with carbon
ion beam irradiation along with unirradiated BRRI dhan29 at BINA farm, Mymensingh

Mutant/variety

Days tomaturity

Plantheight(cm)

Effective
tiller(no.)

Paniclelength(cm)

Filledgrainspanicle -1(no.)

Unfilled
grainspanicle -1
(no.)

Grain
yield/ha(t)

RM(2)-40 (C) -1-1-1

151

112.27

6.93

26.53

139.13

27.00

7.02

RM(2)-40 (C) -1-1-10

149

96.30

8.20

27.00

119.33

23.87

6.93

RM(2)-40 (C) -1-1-7

149

95.53

8.60

25.87

113.60

26.13

5.80

RM(2)-40 (C) -4-2-5

149

91.67

11.40

25.40

109.13

10.87

6.90

RM(2)-40 (C) -4-2-7

159

115.00

8.80

25.73

94.33

18.07

6.53

RM(2)-40 (C) -4-2-8

157

117.60

6.47

28.20

140.60

30.80

6.34

RM(2)-40 (C) -1-1-5

149

112.87

7.93

25.33

136.67

21.07

7.30

RM(2)-40 (C) -3-1-7

147

108.80

7.33

25.80

116.47

21.40

7.10

RM(2)-40 (C) -4-2-2

157

103.07

9.33

25.20

103.73

24.73

6.88

RM(2)-50 (C) -2-1-1

155

115.40

7.80

27.00

169.00

22.87

8.58

BRRI dhan29

159

97.50

10.40

24.57

127.75

22.65

7.23

9.47

1.53

NS

31.42

6.76

0.72

LSD(0.05)
NS- not significant

1.5 Discussion
Heavy ion irradiation has been attaining an important to the mutation breeder as it produced raremutant(s). In view of this, seeds of Ashfal rice and BRRI dhan29 were irradiated with different
doses of carbon ion beams and was grown in Boro season. Three of nine headed plants were foundfertile and the rest six were exhibited sterile in case of Ashfal. Since the Ashfal is a highly
photoperiod sensitive cultivar and none of the control plants headed during Boro season. These-7-

results suggest that photoperiod

sensitivity was altered by carbon ion irradiation in a few M 1 plants.

Plant heights of M 2 progenies were found significantly shorten than Ashfal and this is also observed
consistent with the fact that the fertile M 1 plants had shorter plant height than Ashfal. This might bedue to the fact that the fertile mutant lines shifted from vegetative phase to reproductive phase earlier
than parental Ashfal and it is caused by ion beam irradiation. It has been reported that one dominant
and one recessive genes are responsible for photoperiod sensitivity in rice (Yu and Yao, 1968; Yokoo
and Fujimaki, 1971; Yokoo et al.,1980). It could be happened that carbon ion beams irradiation
inactivated or down regulated the activity of the dominant gene in the irradiated seeds which makes
the M 1 plants homozygous monogenic recessive for photoperiod insensitivity. These facts leaded M 1plants to bred true in M 2 and M3 generations. The M 2 progenies from 160Gy were omitted from theseevaluations because they were prone to lodging for weak culm although they had shorten plants.
Moreover, theseprogenies had shorter panicle with smaller grains and lower number of seed grains.

The mutants derived from 40Gy dose also did not continue after M 3 generation because of theirinferior performance. The grain characteristics such as size and shape although most of the mutants
altered but grain weight mostly remained unchanged as the parent. This also confirmed that the M 1plants that mutated as photoperiod insensitive with shorten plant h eight were not contaminated withother variety. If it was contaminated then 1000-grain weight must differed significantly with Ashfal
and the contaminants. The mutant of BRRI dhan29 showed higher yield and early maturity comparedto parent of BRRI dhan29 which could be due to the useful effect of carbon ion beam.
Hence, it could be concluded that it is possible to induced fixed and stable mutant(s) in M 1 generationof indica type rice Ashfal and BRRI dhan29 through 40-200Gy doses of carbon ion beams irradiation.
This result is also in agreement with the results of Honda et al. (2006) who reported genetically fixedmutants in M 1 generation of sweet pepper for dwarf height and yellow pericarp. Therefore, all ofthese suggest heavy ion beams irradiation has unique properties that induce fixed mutation even in
M1 generation. In other mutational studies showed that mutants are usually detected in M 2 and M3
generations and thus need to handle numerous plants to screen. If mutants can be screened in M 1
generation, the number of plants that must be handle is dramatically decreased. Therefore, further
studies are needed to investigate whether other crop species could induce fixed mutant(s) in M 1
generation.
1.6

Acknowledgements

This work was carried out under the Forum for Nuclear Cooperation in Asia (FNCA) and IAEA/RCA
Mutation Breeding Project. Special thanks to Dr. Atsushi Tanaka, Japan Atomic Energy Agency(JAEA), Ms. Aki Koike, Nuclear Safety Research Association (NSRA) Dr. Liu Luxiang, RCA
Coordinator of China for their kind help and cooperation.

1.7 References
Azad MAK, Hamid MA, and Yasmine F (2010): Binachinabadam-4: a high yielding mutant variety ofgroundnut with medium pod size. Plant Mutation Reports 2(2):45-47.
Azam MA, Uddin I (1999). Binadhan-4, an improved rice variety bred through induced mutation.
Bangladesh J. Nuclear. Agric. 15: 59-65.
-8-

Blakely EA (1992).Cell inactivation by heavy charged particles.Rad. Environ. Biophys. 31:181-196.
Bonilla PS, Dvorak J, Mackill D, Deal K, Gregorio G (2002). RFLP and SSLP mapping of salinity
tolerance genes in chromosome 1 of rice (Oryza sativa L.) using recombinant inbred lines.
Philippines Agric. Sci. 85(1):64-74.
Gregorion GB, Senadhira DRD, Mendoza RD, Manigbas NL, Roxas JP, Guetra CQ (2002). Progressin breeding for salinity and associated abiotic stresses in rice. Field Crops Res. 76:91-101
Hamid MA, Azad MAK, Howelider MAR (2006). Development of three groundnut varieties withimproved quantitative and qualitative traits through induced mutation. Plant Mutation
Reports 1(2): 14-16.
Hase Y, Tanaka A, Baba T, Watanabe H (2000).FRL1 is required for petal and sepal development inArabidopsis. Plant J. 24:21-32.
Hayashi Y, Takehisa H, Kazama Y, Ichida H. Ryuto H, Fukunishi N, Abe T (2007).
beam irradiation on mutation induction in rice. In:

Effects of ion

Proc. Cyclotrons and their applicationsth

2007, 18 International Conference, pp. 237-239.
Hidema J, Yamoto, M, Kumagai T, Hase Y, Sakamoto A, Tanaka A (2003). Biologicaleffects ofcarbon ion on rice (Oryza sativa L.). JAERI- Review 2003-033:85-87.
Honda I., Kikuchi K, Matsuo S, Fukuda M,

Saito H.,

Ryuto H,Fukunishi N, Abe T (2006).

Heavy ion induced mutants in sweet pepper isolated by M 1 plant selection. Euphytica
152:61-66.
Islam MM (2004). Mapping salinity tolerance genes in rice (Oryza sativa L.) at reproductive stage.
Ph.D. Thesis, University of the Philippines Los Banos, College Laguna, Philippines.
Kamruzzaman M, Asaduzzaman M (2004).Cultivation of saline tolerant rice varieties in the coastal
area

to

cope

with

salinityinProtapkhali,paikgacha,

Khulna,Bangladesh.

enviroscope.iges.or.jp/contents/APEIS/inventory/0145.pdf
Niones JM (2004). Fine mapping of the salinity tolerance gene on chromosome 1 of rice (Oryza
sativa L.) using near isogenic line. M.Sc. thesis, University of the Philippines Los Banos,College Laguna, Philippines.
Rakwal R., Kimura S, Shibato J, Nojima K, Kim

YK, Nahm BH, Jwa NS, Endo S, Tanaka K,

Iwahashi H (2008). Growth retardation and death of rice plants irradiated with carbon ion
beams is preceded by very early dose- and time- dependent gene expression changes. Mol.
Cells 25(2):272-278.
-9-

Salil KB, Islam MM, Emon MR, Begum SN, Siddika A, Sultana S (2007). Identification of salt
tolerant rice cultivars via phenotypic and marker assisted procedures. Pakistan J. Biol.
Sci.10(24):4449-4454.
Shamsuzzaman KM, Hamid MA, Azad MAK, Shaikh MAQ (1998).Development of early maturingand high yielding cotton genotypes through induced mutations. Bangladesh J. Nuclear Agric.
14:1-8.
Shikazono N, Yokota Y, Kitamura S, Suzuki C, Watanabe H, Tano S,

Tanaka A(2003). Mutation

rate and novel tt mutants of Arabidopsis thaliana induced by carbon ions. Genetics
163:1449-1455.
Tanaka A, Tano S, Chantes T, Yolota Y, Shikazono N,

Watanabe H (1997). A new Arabidopsis

mutant induced by ion beams affects favonoid synthesis with spotted pigmentation in testa.
Genes Genet.Syst. 72:141-148.
Tanaka A, Sakamoto A, Ishigaki Y,Nikaido O, Sun G, Ase Y, Shikazono N, Tano S, Watanabe H(2002). An ultra violet-B- resistant mutant with enhanced DNA repair in Arabidopsis. Plant
Physiol. 129:64-71.
Vergara BS, Chang TT(1985). The flowering response of the rice plant to photoperiod. The
International Rice Research Institute, Los Banos, Laguna, Philippines.
Yokoo M, Fujimaki H (1971). Tight linkage of blast resistance with late maturity observed indifferent Indica varieties of rice. Japan J. Breed. 21: 35-39
Yokoo M, Kikuchi F, Nakane A, Fujimaki H (1980). Genetical analysis of heading data by aid ofclose linkage with blast resistance in rice. Bull. Nat. Inst.Agric.Sci. D31:95-126.
Yu CJ, Yao TT (1968). Genetische studien beim Reis. II. Die Koppelung des Langhullspelzengens
mit dem Photoperiodizitatsgen. Bot. Bull. Acad. Sin. 9:34-35.

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