India stands third in papaya production, after Brazil
and Nigeria with a 12% share of the total global production
(F.A.O., 2004). The total area under papaya cultivation in
India is about 73,000 ha and the total production is about
0.26 million tonnes (Anon, 2004). It is cultivated chiefly in
Uttar Pradesh, Gujarat, Maharashtra and Tamil Nadu.
Cultivation of papaya is beset with a number of problems
like poor seed viability, sexual propagation, instability in
sex ratio, sensitivity to water logging, frost, hot winds and
susceptibility to fungal and viral diseases.

Papaya being a highly cross pollinated and
polygamous fruit species, produces large variability with

Effect of γγγγγ - irradiation on germination, growth, sensitivity and survivability of papaya
cv. Kesar King

Murlee Yadav, M. S. Kushwah, D. B. Singh, R. K. Roshan and Nongallei Pebam
Department of Horticulture

Allahabad Agricultural Institute- Deemed University
Allahabad – 211 007, India

E-mail: murli_y@yahoo.com

ABSTRACT

An experiment was laid out in a 4x2 factorial design, with 4 levels of γγγγγ-irradiation (0,5,10 & 15 Krad) and two
dates of sowing (15th September and 15th October) on papaya cv. Kesar King. The results indicated that
germination percentage, survival percentage and plant growth increased with the increased in γγγγγ-irradiation
upto 10 Krad. Early sowing of seed (15th September) showed better germination (73%), survival (70%) and
plant growth as compared to late sowing (15th October). Interaction between γγγγγ-irradiation of 10 Krad and early
sowing of seed (15th September) was found superior to all the other treatment combinations to obtain optimum
germination percentage, survival percentage and plant growth.

Key words: γ-irradiation, papaya

respect to plant characters. It is also very difficult to
maintain the purity of variety and uniformity in plants.
Papaya seeds exhibit poor seed viability and germ inability
in stored seeds. Presently, there is a huge demand for healthy
and productive seedlings among papaya farmers. Mutation
by γ-irradiation is used for improvement of fruit crops,
particularly in papaya.

The present investigation was carried out during
2006–2007 in the Department of Horticulture, Allahabad
Agricultural Institute - Deemed University, Allahabad. The
experiment was laid out in a 4 x 2 factorial CRD, comprising
of four levels of γ-irradiation (0, 5, 10 and 15 Krad.) and

Table 1.  Effect of different levels of γγγγγ-irradiation and date of sowing on germination  percentage and survival percentage of Papaya
(Carica papaya L.)

Germination percentage Survival percentage

Date of sowing (D) Mean (R) Date of sowing (D) Mean (R)

γ-Irradiation (R) D
1
(15th Sep.) D

2
(15th Oct.) D

1
   (15th Sep.) D

2
    (15th Oct.)

No irradiation 59.40 55.00 57.20 57.33 52.00 54.67
5 Krad 65.00 62.00 63.50 60.20 60.00 60.10
10 Krad 73.20 70.00 71.60 70.00 65.00 67.50
15 Krad 67.50 66.00 66.75 64.00 63.50 63.75
Mean (D) 66.27 63.25 64.76 62.88 60.13 61.50

R S RxS R S RxS
S.Em ± 0.33 0.46 0.46 0.54 0.77 0.77
CD (P=0.05) 0.70 0.99 0.99 1.17 1.65 1.65

Short communication

J. Hortl. Sci.
Vol. 3 (1): 68-71, 2008

page 68



69

two dates of sowing (15th September and 15th October) on
papaya cv. Kesar King. Observations on germination
percentage, survivability, and growth parameters namely,
plant height, number of leaves per plant, leaf spread,
diameter of stem, and petiole length were taken at 15 days
interval.

 The data pertaining to germination percentage and
survival percentage of papaya, as influenced by different
level of γ-irradiation and dates of sowing are presented in
table 1. A significant increase in germination and survival
percentage was recorded with γ-irradiation of 10 Krad (R

2
).

However, the minimum germination and survival
percentage were recorded with no irradiation (R

0
). Seeds

sown on 15th September (D
1
) recorded significantly higher

percentage of germination (73.20%) and survival percentage
(70%) as compared to (70% and 65%, respectively) 15th

October sowing. Interaction effect of γ-irradiation of 10
Krad and 15th September seed sowing (R

2
 D

1
) recorded the

highest percentage of germination (73.20%) and survival
(70%), whereas the lowest germination (55%) and survival
(52%) were observed with no irradiation in 15th October
sowing. Bankapur and Habib (1979) reported that 5-15 Krad
doses of γ-irradiation increased the germination, survival
and number of male and female flowers and Hafiz et al
(2005) also found maximum germination (87.50%) with
2.5 Krad of γ-irradiation.

The data with respect to plant height recorded at
15 days intervals is presented in table 2. Effect of γ-
irradiation and date of sowing were non-significant at 15
days after sowing (DAS). Plant height was significantly
influenced by γ - irradiation and date of sowing from 30
DAS. The maximum plant height at 30, 45, 60, 75, 90 DAS
was recorded in 10 Krad (R

2
), whereas minimum plant

height was observed with no irradiation (R
0
). Interaction

effect of γ - irradiation of 10 Krad and sowing date of 15th
September recorded the maximum plant height. However,
minimum plant height was observed with the interaction
between no irradiation (R

0
) and 15th October sowing.

The data presented in table 2 revealed that number
of leaves per plant was significantly influenced by different
level of γ-irradiation and dates of sowing from 30 DAS.
The maximum number of leaves per plant 16.06,24.00,34.33
at 60, 75, 90 DAS was recorded in 10 Krad (R

2
) on 15th

September sowing whereas it was  minimum 8.23, 17.88,
21.68 with no irradiation (R

0
) on 15th October sowing.

Interaction effect of γ - irradiation of 10 Krad and sowing

date of 15th September was found to have maximum number
of leaves per plant at all intervals. However, minimum
numbers of leaves per plant was observed with the
interaction between no irradiation (R

0
) and sowing date of

15th October at all interval.

The data pertaining to leaf spread at 15 day
intervals is presented in table 3. Effect of γ-irradiation and
date of sowing was found non-significant with leaf spread
at 15 DAS. The leaf spread was significantly influenced by
γ - irradiation and date of sowing from 30 DAS. The
maximum leaf spread at 30, 45, 60, 75, 90 DAS was
recorded in 10 Krad (R

2
) at 15th Sept. sowing while

minimum leaf spread was observed with no irradiation (R
0
).

Interaction effect of γ - irradiation of 10 krad and 15th
September sowing was found  maximum in leaf spread at
all interval i.e.,  60, 75, 90 DAS. While it was minimum
with interaction between no irradiation (R

0
) and 15th October

sowing at all interval. Hafiz et al (2005) also found
maximum germination (87.50%) with 2.5 Krad of γ -
irradiation.

The data in respect of stem diameter at 15 day
intervals is presented in table 3. Effect of γ-irradiation and
date of sowing was found non-significant in stem diameter
at 15 DAS, while it was significantly affected 30 days after
sowing. The maximum stem diameter at 60, 75, 90 DAS
were recorded in 10 Krad (R

2
) at 15th Sept. sowing whereas

minimum with no irradiation (R
0
). Interaction effect of

γ - irradiation of 10 Krad and 15th September sowing showed
maximum stem diameter at all intervals. However,
minimum stem diameter was observed with the interaction
between no irradiation (R

0
) and 15th October sowing.

The data presented in table 4 revealed that Petiole
length was significantly influenced by different level of
γ-irradiation and dates of sowing from 30 DAS. The
maximum petiole length at 60, 75, 90 DAS was recorded
in 10 krad (R

2
) on 15th September sowing whereas it

recorded minimum with no irradiation (R
0
). Interaction

effect of γ-irradiation of 10 Krad and 15th September sowing
on petiole length was maximum at all the interval.  However,
it was minimum with the interaction between no irradiation
(R

0
) and 15th October sowing.

ACKNOWLEDGEMENTS

The authors are thankful to the Head, Deptt. of
Horticulture, AAI-DU for providing research facilities for
the work.

Effect of γ-irradiation on papaya plant

J. Hortl. Sci.
Vol. 3 (1): 68-71, 2008



70

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J. Hortl. Sci.
Vol. 3 (1): 68-71, 2008

Murlee Yadav et al



71

Table 4. Petiole length (cm) as influenced by different level of γγγγγ - irradiation and dates of sowing
Petiole length (cm)

60 DAS 75 DAS 90 DAS
ã-Irradiation Date of sowing (D) Mean (R) Date of sowing (D) Mean (R) Date of sowing (D) Mean (R)
(krad) D

1
D

2
D

1
D

2
D

1
D

2

0 1.91 1.84 1.88 4.47 3.65 4.06 7.40 5.40 6.40
5 5.40 3.11 4.25 6.87 5.74 6.30 10.50 8.30 9.40
10 8.71 8.33 8.52 12.67 10.73 11.70 14.65 13.87 14.26
15 7.43 6.37 6.90 10.43 10.11 10.27 13.27 12.67 12.97
Mean (D) 5.86 4.91 5.39 8.61 7.56 8.08 11.46 10.06 10.76

R S RxS R S RxS R S RxS
S.Em ± 0.16 0.11 0.22 0.16 0.11 0.23 0.19 0.13 0.26
CD(P=0.05) 0.34 0.24 0.48 0.34 0.24 0.49 0.40 0.28 0.57

REFERENCES

Anonymous, 2005. National Horticulture Board.
Horticulture data base.

Bankapur, V. M. and Habib, A. F. 1979. Mutation studies
in papaya (Carica papaya). Mysore J. Agril. Sci.,

13:113-116.
Hafiz, I. A., Naveed, Anwar, Abbas, N. A. and Asi, A. A.

2005. Effect of various doses of g-radiation on the
seed germination and seedling growth of mango-
Sarad. J. Agri., 21 : 63-567.

(MS Received 28 September 2007, Revised 5 February 2008)

J. Hortl. Sci.
Vol. 3 (1): 68-71, 2008

Effect of γ-irradiation on papaya plant