Journal of Oil Palm Research Vol. 31 (2) June 2019 p. 212-219
JDoOurI:n hatlt posf: /o/dilo Pia.olrmg r/1e0s.e2a1r8c9h4 3/j1o (p2r) .(2Ju0n1e9 .2000192)0
MUTAGENIC EFFECTS OF GAMMA 
IRRADIATION ON OIL PALM (Elaeis guineensis 
Jacq.) SEEDLING GERMINATION AND GROWTH
DICKSON OSEI DARKWAH*; ESSIE T BLAY**; HARRY M AMOATEY‡; DANIEL AGYEI-DWARKO*; 
ENOCH SAPEY* and MEILINA ONG-ABDULLAH‡‡
ABSTRACT
Mutation induction has been used to generate genetic variability in most crop plants. This research was 
conducted to assess genetic variation induced by gamma radiation on the various treatment designated 
as M1, M2, M2M1 at 10 Gy. A randomised complete block design with four replicates was used for the 
experiment. Parameters such as percentage germination, root length, leaf area, plant height and stem/trunk 
circumference were taken from 4- to 12-month seedlings after planting. Data was analysed using GenStat 
(12th edition), which revealed significant differences in germination and growth of these oil palm seedlings. 
The study shows that percentage germination as well as growth parameters were stimulated in the M1 
seedlings but inhibited in the M2 and M2M1  populations.
Keywords: mutation breeding, dose, genetic variability, improvement. 
Date received: 26 September 2018; Sent for revision: 30 September 2018; Received in final form: 3 March 2019; Accepted: 30 April 2019.
INTRODUCTION oil with demand estimated to reach 240 million 
tonnes by 2050 (Corley, 2009). Restricted genetic 
The high yields, low cost, and stability of palm oil base of the oil palm coupled with the long breeding 
makes it the most widely used vegetable oil in the cycle generally result in a slow genetic progress 
world, and global production of the commodity is from one cycle of selection to another, hampering 
steadily rising in response to population growth and significant improvement of the crop. According to 
policies that promote the use of palm and other oils Wonkyi-Appiah (2013), new sources of variation 
in biofuels (Petrenko et al., 2016). Its rapid growth need to be introduced into the oil palm breeding 
has also drawn negative attention that requires the programme to enhance selection for high yields 
industry to manage public sensitivities especially in and other useful traits. Aside from leveraging the 
issues pertaining to health and environment, and to genetic resources (Rajanaidu et al., 2017), Kushairi et 
swiftly address them to ensure that the industry’s al. (2017) introduced the concept of transformative 
competitive edge is not jeopardised (Kushairi et technologies providing the relevant tools to further 
al., 2017). Regardless of the sentiment, the palm oil enhance research.   These technologies continue 
is still the largest internationally traded vegetable to improve over time and as more successful 
applications in the plant system are reported 
* CSIR-Oil Palm Research Institute, P. O. Box 74, Kade, Ghana. (Kushairi et al., 2018), this will provide the impetus 
** Crop Science Department, University of Ghana, for commodity crop such as the oil palm to leverage 
 P. O. Box LG 25, Legon, Accra, Ghana. these advancements. 
‡ Ghana Atomic Energy Commission, P. O. Box LG 80, 
 Legon, Accra, Ghana. One of the ways of accelerating oil palm breeding 
‡‡ and development of novel traits is by mutation Malaysian Palm Oil Board, 6 Persiaran Institusi, 
 Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia. induction. Although not a new technology, it is still 
 E-mail: meilina@mpob.gov.my very relevant. According to Roychowdhury and Tah 
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muTaGenic effecTs of Gamma irraDiaTion on oil Palm (Elaeis guineensis Jacq.) seeDlinG GerminaTion anD GroWTh
(2013), mutation in crop species can significantly Commission (GAEC) at a dosage of 10 Gy radiation 
increase genetic variability and accelerate many sourced from cobalt-60.
breeding programmes. Induced mutations, using 
chemical or physical mutagens, is a suitable Field Experiment
approach to producing variation in plant breeding 
(Hakeem et al., 2013; Roychowdhury and Tah, 2011; The research was carried out at the OPRI nursery. 
Domingo et al., 2007). This can produce several Hundred germinated seeds of each treatment were 
improved mutant varieties with high demand and sown singly in black polybags (35.6 cm x 45.7cm) 
economic value (Din et al., 2004). Induced mutants filled with a mixture of topsoil and sand at the ratio 
also have superior characters such as short stature of 2:1 (Wonky-Appiah, 1976).
and lodging resistance, disease resistance, improved A randomised complete block design (RCBD) 
oil quality and increased nitrogen fixation (Hakeem was established for the experiment involving four 
et al., 2013). Therefore mutation breeding through treatments with four replications and 25 plants 
gamma irradiation may be a useful tool in creating per plot. Standard cultural practices were carried 
variation in oil palm. Through a study conducted out accordingly. Root length was determined non-
by Rohani et al. (2012), oil palm callus cultures were destructively at three months after planting (MAP). 
subjected to gamma irradiation and the subsequent Plant height, butt circumference and leaf area were 
clones produced were field planted. At high recorded monthly from 4 to 12 MAP on 10 palms 
dosages, modifications to specific physiological and randomly selected from each plot (treatment).
vegetative characteristics such as the biomass were Germination frequency was determined by the 
observed (Samsul Kamal et al., 2014). The objectives formula:
of this study are to induce variation in oil palm using 
gamma irradiation and subsequently to determine Germination      =   Germinated seeds     x 100
its effect on seed germination and seedling growth percentage (%)       Total seeds sent for 
at the nursery.       germination 
 
Root Length (cm)
MATERIALS AND METHODS
This was determined at 3 MAP. Polybags with 
Seeds for this experiment were obtained from M1 seedlings were soaked with water to allow easy 
population at the Oil Palm Research Institute (OPRI) removal of ball of soil around the root. A piece of 
in Ghana developed by Wonky-Appiah in 1976. thread was laid alongside the longest root and its 
These seeds were derived from the commercial Deli equivalent length on a meter rule taken as the 
dura x Aba pisifera (Nigeria) cross. The M1 palms reading. 
irradiated at 10 Gy showing superiority in yield 
were selected. Two thousand and one hundred Number of Leaves Per Plant
M2 seeds produced under controlled pollination 
of the selected M1 palms were at 17% moisture This was determined by counting the number 
content before being irradiated to produce recurrent of leaves on a seedling on a monthly basis from 4 to 
irradiation population (M2M1) at 10 Gy. Non- 12 MAP. 
irradiated seeds from a commercial oil palm variety 
as well as irradiated seeds (M1) of the same variety Plant Height (cm)
were obtained from the Plant Breeding Division of 
OPRI. Part of the non-irradiated seeds was used as a This was measured as height from the soil 
control (M0) (Table 1). level in the polybag to the tip of the highest leaf 
Irradiation of seeds was done at the Radiation using a meter rule at monthly intervals from 4 to 
Technology Centre of the Ghana Atomic Energy 12 MAP. 
TABLE 1. IRRADIATION TREATMENTS APPLIED ON OIL PALM SEEDS
Treatments Designation Dosage (Gy) Quantity of seed
  of irradiation for germination
Commercial seed not irradiated M0 0 500
Commercial seed that is irradiated M1 10 2 100
Selfed M1 seeds M2 10 2 100
Re-irradiated M2 seeds (recurrent irradiation) M2M1 10 2 100
Note: Eighty seeds of each treatment were used for routine moisture content and viability test. Seeds were 
germinated using the dry heat method (Hartley, 1988) for three to four months.
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Journal of oil Palm research 31 (2) (June 2019)
Butt Circumference (cm) Effect of gamma irradiation on shoot system 
(above ground structures) at 4-12 MAP. Table 3 
Butt circumference was determined monthly shows the mean leaf area from 4-12 MAP for the 
by using a pair of veneer callipers to measure various treatments. Significant differences (P≤ 0.05) 
the diameter at two places on the butt. The occurred between M0, M2 and M2M1 but not M1. 
circumference was determined by the formula πd Though significant difference did not occur between 
where π was taken as 3.14 and d is the average M1 and M0, highest values were recorded in the M1 
diameter measured. treatment.
Significant differences at P≤0.05 for plant 
Leaf Area (cm2) height were observed among the treatments (Table 
4) with M1 been the tallest followed by M0, M2 and 
A non-destructive method was used. The length M2M1 in that order for all the recorded months. At 
and greatest width of each leaf was measured with four months after planting, significant difference 
a ruler on each of the recorded plants sampled per occurred between M2 and M2M1 but in the 
plot. Leaf area was then estimated according to the subsequent months M2 seedlings remained taller 
formula by Hardon et al. (1969). than M2M1 seedlings even though the differences 
 were less obvious.
 A - b (nlw) There was no significant difference at P≤0.05 
where:    among the treatments with respect to butt 
A - leaf area.          b - correction factor (0.57).   circumference until the eight month (Table 5). 
n - number of leaves.      Although significant difference was not observed, 
lw - is mean of length and width of sample of the six M1 seedlings generally had the largest butt from the 
largest leaflet.
GenStat software was used to generate analysis 120
of variance (ANOVA) for the data collected. Where 100
significant differences were observed between 80
treatments, the Least Significant Differences (LSD) 60
at P=0.05 was used to separate the means. 40
20
RESULTS 0
M0   M1   M2   M2M1
Effects of Gamma Irradiation on Growth and Irradiation treatment
Development of Oil Palm Seedlings Figure 1.  Percentage germination of irradiated oil palm seeds.
Figure 1 shows percent germination of oil palm 
seeds following irradiation treatments. Germination TABLE 2. MEAN ROOT LENGTH OF OIL PALM 
percentage was highest in M1 (93.22%) followed by 
SEEDLINGS AT THREE MONTHS AFTER 
M0 (79.52%), M2 (70.35%) and M2M1 (10.74%). 
PLANTING (MAP)
 Treatments Mean root length (cm)
Effect of gamma irradiation on root system (below  
ground structures) at 3 MAP. The mean root lengths  M c0 22.75
of seedlings of the various treatments at 3 MAP  M1 38.38a
c
are displayed in Table 2. There were significant  M2 26.36b
b
differences (P≥0.05) in mean root length at 3 MAP.  M2M1 29.05
All the irradiated materials had longer roots than Note: Means with the same letter (s) are indicative of no significant 
the control. difference at a 5% probability level.
TABLE 3. INFLUENCE OF GAMMA IRRADIATION ON MEAN LEAF AREA OF SEEDLINGS 
FROM 4-12 MONTHS AFTER PLANTING (MAP)
      Months after planting
Treatments
  4 5 6 7 8 9 10 11 12
 M0 119.42bc 179.00b 333.00b 807.00ab 1 167.00ab 1 709.21ab 2 250.00a 3 000.12a 4 903.21a
 M  154.31a 229.00a 389.00a 1 042.00a 1 491.00a 2 110.23a 2 585.00a1  3 344.61a 5 498.02a
 M2 91.61c 160.00b 281.00b 596.00b 914.00b 1 293.11bc 1 626.00b 2 216.54b 3 473.10b
 M2M1 85.00c 130.00b 218.00b 499.00b 720.00b 1 009.15b 1 255.00b 1 703.07b 2 589.03b
Note: Means with the same letter (s) are indicative of no significant difference at a 5% probability level.
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Germination (%)
muTaGenic effecTs of Gamma irraDiaTion on oil Palm (Elaeis guineensis Jacq.) seeDlinG GerminaTion anD GroWTh
TABLE 4. EFFECTS OF GAMMA IRRADIATION ON MEAN PLANT HEIGHT FROM 4-12 MONTHS AFTER PLANTING
    M onths after planting
Treatments
  4 5 6 7 8 9 10 11 12
 M0 23.93a 25.84a 29.81a 38.77a 46.07a 53.20a 60.40a 68.8a 86.4a
 M  26.00a 27.28a 32.77a 43.13a1  49.85a 57.30a 65.70a 72.7a 91.7a
 M2 20.66b 21.24b 24.91b 31.10b 37.00b 43.50b 50.70b 54.8b 70.2b
 M2M1 19.91b 20.27b 22.52b 27.98b 32.78b 37.60b 43.3b 47.7b 59.6b
Note: Means with the same letter (s) are indicative of no significant difference at a 5% probability level.
TABLE 5.  EFFECTS OF GAMMA IRRADIATION ON MEAN BUTT CIRCUMFERENCE 4-12  MONTHS 
AFTER PLANTING (MAP)
 Treatments     Months after planting
  4 5 6 7 8 9 10 11 12
 M  3.02a 3.75a0  5.27a 6.19a 8.88a 10.68ab 11.29b 14.61a 20.79ab
 M1 3.25a 4.28a 5.87a 7.24a 9.56a 11.98a 12.90a 15.61a 22.64a
 M  2.92a 3.76a 5.16a 5.93a 8.16ab 9.92b 10.18bc 12.86b 18.81bc2
 M2M1 2.62a 3.29a 4.72a 5.28a 7.50b 8.70b 8.93c 9.14b 16.60c
Note: Means with the same letter (s) are indicative of no significant difference at a 5% probability level.
fourth to the seventh MAP followed by M0, M2 and factors such as temperature and light intensity. 
M2M1 respectively. At 8 MAP, seedlings in treatment Correspondingly, Sjodin (1962) reported that 
M1 had the highest butts followed by control but enzymatic activity as well as the awakening of young 
the difference between them were not significant. embryo may be enhanced by low doses of gamma 
Treatments M2 and M2M1 however had significantly irradiation resulting in a stimulatory effect on the 
smaller butts than the former treatments. rate of cell division and subsequently affecting both 
germination and vegetative growth.
The result of the present study is in accordance 
DISCUSSION with earlier reports by various authors. Wonkyi-
Appiah  and Amu (1976) obtained up to 72% 
M1 seeds which had the highest germination germination in oil palm seeds subjected to gamma 
percentage might be due to the stimulatory effect irradiation without heat treatment. He reported 
of gamma radiation at a low dosage. Sapey (2015) that even though high doses (above 50 Gy) gave 
in determining the optimal dose for oil palm higher germination percentage, further growth at 
mutation induction concluded that 9.5-11 Gy and the emergence of the embryo was greatly retarded. 
8-13 Gy  was the optimum dose for Cross 131 and The control (non-irradiated material) did not 
132 respectively. Gamma irradiation dose used for germinate during the experimental period of eight 
the present study was 10 Gy which falls within the weeks.  Kiong et al. (2010) reported that growth of 
optimal dose for the two varieties studied by Sapey citrus plant was stimulated at 10 Gy with increased 
(2015) and might have accounted for the 93.22% germination percentage as compared with the 
germination. control. Akshatha et al. (2013) working on the effect 
According  to  Sadegh et al. (2014), low exposure of of gamma irradiation on germination, growth, and 
materials to gamma irradiation caused a stimulatory biochemical parameters of Terminalia arjuna Roxb 
effect while higher exposures were inhibitory due concluded that low doses of gamma irradiation 
to the reduction in mitotic activity. The cause of the significantly increased the germination percentage 
stimulation might be due to hormonal changes in the compared to the control. Similar results were 
plant cell, increased oxygen uptake which caused a obtained by Toni et al. (2013) who studied effects 
production of organic and inorganic peroxy radicals of gamma irradiation in tomato seeds and reported 
leading to breakage of seed dormancy (Sadegh et that low doses of gamma irradiation stimulated 
al., 2014; Ling et al., 2008; Norfadzrin et al., 2007). In germination, vegetative growth, number and weight 
addition, Abdel-Hady et al. (2008) and Moghaddam of harvested fruits of tomato and that highest yield 
et al. (2011) reported that the cause of the stimulation of fruits was produced at 10 Gy. Various authors 
of germination at low dose of gamma irradiation (Akshatha et al., 2013; Aynebhand and Afsharinafar, 
might be due to ribonucleic acid (RNA) or protein 2012; Selvaraju and Raja, 2001) have all concurred 
synthesis activation after seed irradiation and with the stimulatory effects of low doses of gamma 
improvement in the oxidative capability of cells irradiation on germination, vegetative growth and 
leading to the reduction or domination in stress yield.
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Journal of oil Palm research 31 (2) (June 2019)
The populations subjected to recurrent to control (M0) plants. The stimulatory effect of 
irradiation (M2M1) had lower germination lower doses of gamma irradiations on growth of 
frequencies (10.74%). This might be due to inhibitory plants might be due to stimulation of cell division, 
effect posed by the recurrent gamma irradiation alteration of metabolic processes that affect 
treatment. The inhibitory effect could be caused synthesis of nucleic acids (Ilyas and Naz, 2014). 
by increase in stress factors, reduced mitotic and According to Mounir et al. (2015), irradiating 
enzymatic activities leading to low shoot and root seeds with a 20 Gy dose (low dose) prior to 
proliferation. M2 seeds had 70.35% germination sowing significantly increased growth promoters 
percentage which signifies that gamma irradiation gibberellic acid (GA) and auxin and insignificantly 
had severe inhibitory effect on the recurrent decreased growth inhibitor, abscisic acid (ABA). 
irradiation population (M2M1). It can therefore be Grover and Khan (2014) concluded that gamma 
deduced that low dosage of gamma irradiation irradiation at a low dose stimulates, while a high 
provides positive stimulation for germination whilst dose inhibits plant growth and development. 
further exposure to gamma irradiation especially Grover and Khan (2014) also reported that the 
when applied repeatedly have an inhibitory effect induced stimulation of plant growth at low dosage 
on germination as reflected in the M2M1 materials. causes changes in the biochemical characteristics of 
According to Tinker and Corley (2003), the dry target tissue or plants which directly or indirectly 
heat method of germination should give above 85% regulate cell division and cell elongation and hence 
germination. The current germination percentage the morphological aspects and consequently the 
with the dry heat method at CSIR-OPRI falls within related physiological attributes increase. 
the range of 79%-82% (Obeng Godfred, pers. comm.). The results obtained in this study corroborated 
All the treatments except the M1 population (93.22%) the findings of other authors. Grover and Khan 
rose above this value implying that germination of (2014) also reported that significant differences 
seeds could be increased by the use of low doses of occurred between seeds of wheat irradiated with 
gamma radiation. An increase of about 11%-14% in gamma irradiation at various dosages but maximum 
germination over the control can bring good returns height was obtained in wheat seeds irradiated at 10 
to oil palm seed producers. Gy. Minisi et al. (2013) reported a significant increase 
The stimulation of cell division and elongation in height following the application of low dose 
by the low dose of gamma irradiation might have of gamma irradiation compared to the control in 
led to the increase in root length of M1 seedlings. Moluccella laevis (L).
This was supported by several independent studies Though higher doses were not used in this 
done on other crops. Sasikala and Kalaiyarasi (2010) study, recurrent irradiation through gamma rays 
reported that low dose of gamma irradiation can caused inhibition effect in plant height. The reason 
increase root length while high doses caused a accounting for reduction in the height of plant 
stunted root growth in rice. Akshatha et al. (2013) in the M2M1 and M2 population, might be due to 
also observed a similar trend in Terminalia arjuna inhibitory effect produced by the gamma irradiation 
Roxb. Gamma irradiation at 25 Gy increased the due to reduced mitotic division in meristematic 
root length over the control but with doses above tissues and reduced moisture content (Khalil et al., 
25 Gy root lengths were significantly reduced. 1986), interruption in DNA synthesis and other 
Furthermore, Ikram et al. (2010) also affirmed that physiological and biochemical changes (Sasikala 
gamma irradiation at low doses (15, 30 and 60 Gy) and Kalaiyarasi, 2010). The cause of the inhibition 
increased significantly the root length of mung bean by high doses might be due to oxidative stress with 
but beyond these there was a reduction in the root overproduction of reactive oxygen species such as 
length compared to the control. super oxide radicals (O-), hydroxyl radicals (OH-) 
The low dose (10 Gy) of gamma irradiation and hydrogen peroxides (H2O2), which react rapidly 
might have caused the stimulation of cell division with almost all structural and organic molecules 
and elongation in M1 palms leading to larger and causing disturbance of cellular metabolism (Garcia 
longer leaves which ultimately increased the leaf et al., 2000). This result is in harmony with Nunoo et 
area in the M1 palms. Ilyas and Naz (2014), reported al. (2014) who also reported a reduction in the height 
significant increase in average leaf width and length of tomato plants following recurrent irradiation.
after gamma irradiation at 10 Gy of Faisalabad Height reduction of about 31.01% at 12 MAP 
genotype of Curcuma longa (L) which resulted in in the M2M1 population may have a potential of 
an increase in the leaf area. Islam et al. (2015) also producing the dwarf or semi dwarf trait. Dwarf 
affirmed that the leaf area of grape saplings (Vitis traits are of great importance to oil palm breeders 
vinifera L.) were significantly higher at 10 Gy as as this will extend the economic life of the palm, 
compared to the control plants. increase the efficiency of harvesting and as well 
Gamma irradiation treatments significantly facilitate mechanization of harvesting (Barcelos et 
increased the plant height in the M1 population al., 2015).  The M2M1 seedlings may be planted for 
and reduced the height of M2 and M2M1 compared further observation. If they are found to be dwarfish, 
216
muTaGenic effecTs of Gamma irraDiaTion on oil Palm (Elaeis guineensis Jacq.) seeDlinG GerminaTion anD GroWTh
subsequent generations can be developed and tested for yield improvement. Frontier Plant Science, 6: 190. 
for stability of the trait and possible incorporation DOI:10.3389/fpls.2015.00190.
into future breeding progamme of the OPRI.
There was no significant difference among Corley, R H V (2009). How much palm oil do we 
treatments for butt circumference from the 4-7 MAP. need? Environ. Sci. Policy, 12: 134-139. https://doi.
This might be due to slow growth and development org/10.1016/j.envsci.2008.10.011
of the oil palm in initial stages. Danso et al. 
(2012) reported no significant differences on butt Danso, F; Opoku, A; Baidoo-Addo, K; Danso, I; 
circumference and other traits from 4-7 MAP and Afari, P A and Nuertey, B N (2012). Improving the 
attributed it to the inherent sluggish growth pattern growth of oil palm seedlings with biostimulants 
of the seedlings. Significant difference occurred NEB-26 and NEB-29. J. Ghana Science Association, 
from the 8-12 MAP. Plants might have fully grown 14(1): 46-52.
and were exhibiting their peak expression of this 
trait. Din, R; Qasim, M and Ahmad, K (2004). Radio 
sensitivity of various wheat genotypes in M1 
generation. International J. Agricultural Biology, 6: 
100 μmCONCLUSION 898-900.
Gamma irradiation of oil palm seeds led to both Domingo, C; Andres, F and Talon, M (2007). Rice cv. 
stimulation and inhibition in germination and Bahia mutagenized population: A new resource for 
growth parameters of oil palm seedlings. Gamma rice breeding in the Mediterranean Basin. Spanish J. 
irradiation led to about 14% increase in germination Agricultural Research, 5: 341-347.
frequency. There was about 31.01% reduction in 
the height of M2M1 which may have a potential Garcia, M X U; Foote, C; Van Es, S; Devreotes, P N; 
of introducing the dwarf trait into our breeding Alexander, S and Alexander, H (2000). Differential 
programme. From the results obtained on this developmental expression and cell type specificity 
experiment, it is clear that gamma irradiation could of Dictyostelium catalases and their response to 
be a useful means of inducing variability in oil palm oxidative stress and UV-light. Biochemistry Biophysics 
for the genetic improvement of the crop. Acta, 1492: 295-310. 
Grover, S and Khan, A S (2014). Effect of ionizing 
ACKNOWLEDGEMENT radiation on some characteristics of seeds of wheat. 
International J. Science and Technology Research, 3: 32-33.
The authors express their profound gratitude to 
OPRI for funding this research. Hakeem, K R; Ahmad, P and Ozturk, M (2013). Crop 
Improvement: New Approaches and Modern Techniques. 
Springer Science + Business Media, New York. p. 
100 μm REFERENCES 1-16. 
Abdel-Hady, M S; Okasha, E M; Soliman, S S A Hardon, J J; Williams, C N and Watson, I (1969). Leaf 
and Talaat, M (2008). Effect of gamma radiation area and yield in the oil palm in Malaya. Experimental 
and gibberellic acid on germination and alkaloid Agriculture, 5(01): 25-32.
production in Atropa belladonna. Australian J. Basic 
and Applied Science, 2(3): 401-405. Hartley, C W (1988). The Oil Palm. Longmans, London. 
p. 1-761.
Akshatha; Chandrashekar, K R; Somashekarappa, 
H M and Souframanien, J (2013). Effect of gamma Ikram, N; Dawar, S; Abbas, Z and Javed, Z (2010). 
irradiation on germination, growth, and biochemical Effect of (60Co) gamma rays on growth and root rot 
parameters of Terminalia arjuna Roxb. Radiation diseases in mung bean (Vigna radiata L.). Pakistan J. 
Protection Environment, 36: 38-44. Botany, 42(3): 2165-2170.
Aynebhand, A and Afsharinafar, K (2012). Effect of Ilyas, S and Naz, S (2014). Effects of gamma 
gamma irradiation on germination characters of irradiation on morphological characteristics and 
amaranth seeds. European J. Experimental Biology, 2: isolation of curcuminoids and oleoresins of Curcuma 
995-999. longa L. The J. Animal and Plant Science, 24(5): 1369-
1404.
Barcelos, E; Rios, S A; Cunha, R N V; Lopes, R; 
Motoike, S Y; Babiychuk, E; Skirycz, A and Kushnir, Islam, A F M S; Islam, M M and Hasan, M M (2015). 
S (2015). Oil palm natural diversity and the potential Effect of gamma irradiation doses on morphological 
217
Journal of oil Palm research 31 (2) (June 2019)
and biochemical attributes of grape saplings. the improvement of a variant line of wild tomato 
Agricultural Sciences, 6: 505-512. (Solanum pimpinellifolium). J. Radiation Research 
and Applied Sciences, 7(4): 377-383. http://doi.
Khahil, S J; Rehnan, S; Afridi, K and Jan, M T org/10.1016/j.jrras.2014.07.007.
(1986). Damage induced by gamma irradiation 
in morphological and chemical characteristics of Obeng Godfred (2017). Personal communication, 10 
barley. Sarhad J. Agriculture, 2: 45-54. July 2017.
Kiong, A P L; Cheng, J X O; Hussein, S and Abdul, Petrenko, C; Paltseva, J and Searle, S (2016). 
R H (2010). Morphological and physiological Ecological impacts of palm oil expansion in 
responses of Orthosiphon stamineus callus to gamma Indonesia [White paper]. International Council 
irradiation at different doses. World J. Agricultural on Clean Transportation. http://www.theicct.org/
Sciences, 6(1): 58-66. sites/default/files/publication/Indonesia-palm-
oil-expansion_ICCT_july2016.pdf, accessed on 21 
Kushairi, A; Loh, S K; Azman, I; Elina, H; Ong- September 2016.
Abdullah, M;  Zanal Bidin, M N I; Razmah, G; 
Sundram, S and Parveez, G K A (2018). Oil palm Rajanaidu, N; Kushairi, A and Mohd Din, A (2017). 
economic performance in Malaysia and R&D Monograph Oil Palm Genetic Resources. MPOB, Bangi. 
progress in 2017. J. Oil Palm Res. Vol. 30(2): 163-195. 289 pp.
DOI: https: //doi.org/10.21894/jopr.2018.0030.
Rohani, O; Samsul Kamal, R; Rajinder, S and Mohd-
Kushairi A; Singh, R and Ong-Abdullah, M (2017). Nazir, B (2012). Mutation induction using gamma 
The oil palm industry in Malaysia: Thriving with irradiation on oil palm (Elaeis guineensis Jacq.) 
transformative technologies. J. Oil Palm Res. Vol. cultures. J. Oil Palm Res. Vol. 24: 1448-1458.
29(4): 431-439. DOI: https: //doi.org/10.21894/
jopr.2017.00017. Roychowdhury, R and Tah, J (2011). Assessment of 
chemical mutagenic effects in mutation breeding 
Ling, A P K; Chia, J Y; Hussein, S and Harun, A R programme for M1 generation of carnation 
(2008). Physiological responses of Citrus sinensis to (Dianthus caryophyllus). Research in Plant Biology, 
gamma irradiation. World Applied Sciences J., 5: 12-19. 1(4): 23-32.
Minisi, F A; El-Mahrouk, M E; El-Din, M; Rida, Roychowdhury, R and Tah, J (2013). Mutagenesis – 
F and Nas-Mary, N (2013). Effects of gamma A potential approach for crop improvement. Crop 
radiation on germination, growth characteristics Improvement (Hakeem, K R et al., eds.). Springer 
and morphological variations of Moluccella laevis L. Science+Business Media, LLC. p. 149-187. DOI 
American-Eurasian J. Agricultural & Environmental 10.1007/978-1-4614-7028-1_4. 
Science, 13(5): 696-704.
Sadegh, M; Rosna, M T; Ma-Ma, L; Arash, K E and 
Moghaddam, S S; Jaafar, H; Ibrahim, R; Rahmat, Khalili, M (2014). Stimulatory effects of gamma 
A; Aziz, M A and Philip, E (2011). Effects of acute irradiation on phytochemical properties, mitotic 
gamma irradiation on physiological traits and behaviour and nutritional composition of Sainfoin 
flavonoid accumulation of Centella asiatica. Molecules, (Onobrychis viciifolia Scop.). The Scientific World J., 
16(6): 4994-5007. 85403: 1-9.
Mounir, A M; El-Yazid, A A; Orabi, I O A; Zahran, Samsul Kamal, R; Mohd Roslan, M N; Tarmizi, A H; 
A A and El-Oksh, I I (2015). Effect of sowing date, Marhalil, M and Rohani, O (2014). Field observation 
gamma irradiation and inter cultivar differences on of clonal oil palms irradiated with gamma rays. Oil 
growth, pod characteristics and some endogenous Palm Bulletin No. 68: 5-7.
plant growth regulators in snap beans. World J. 
Agricultural Sciences, 11(6): 380-390. Sapey, E (2015). Mutation induction in oil palm 
(Elaeis guineensis Jacq.) using gamma irradiation: A 
Norfadzrin, F; Ahmed, O H; Shaharudin, S and preliminary studies. CSIR-OPRI/TR/E.S/2015/10. 
Rahman, D A (2007). A preliminary study on 
pigments and antioxidant machinery of red pepper Sasikala, R and Kalaiyarasi, R (2010). Sensitivity of 
(Capsicum annuum L.) seedlings from gamma rice varieties to gamma irradiation. Electronic J. Plant 
irradiated seeds. J. Plant Biology, 47: 314-321. Breeding, 1(4): 885-889.
Nunoo, J; Quartey, E K; Amoatey, H M and  Klu, Selvaraju, P and Raja, K (2001). Effect of gamma 
G Y P (2014). Effect of recurrent irradiation on irradiation of seeds on germination of different 
218
muTaGenic effecTs of Gamma irraDiaTion on oil Palm (Elaeis guineensis Jacq.) seeDlinG GerminaTion anD GroWTh
tree species. IUFRO Joint Symposium on Tree Seed Toni, W A; Fritz, W; Paula, A B; Franco, S S H; José, 
Technology, Physiology and Tropical Silviculture. F G and Valter, A (2013). Effects of gamma radiation 
Laguna, Philippines. 66 pp. in tomato seeds. International Nuclear Atlantic 
Conference - INAC 2013. p. 1-4.
Sjodin, J (1962). Some observations in X1 and Wonkyi-Appiah, J B (2013). Selection in the oil palm 
X2 of Vicia faba L. after treatment with different (Elaeis guineensis Jacq.). Ghana J. Agric Science, 46: 27-33.
mutagenesis. Hereditas, 48: 565-573. 
Wonkyi-Appiah, J B and Amu, I K A (1976). 
Preliminary investigations into the use of gamma 
Tinker, P B and Corley, R H (2003). The Oil Palm irradiations to induce germination in the seed of the 
(Corley, R H V and Tinker,  P B eds.). Oxford, UK: oil palm (Elaeis guineensis Jacq.). Ghana J. Agricultural 
Blackwell Science Ltd. p. 1-608. Science, 9: 235-236.
219