Among the agricultural commodities exported from
India, cashew held the fifth position contributing 0.35% of
the total export earnings of the country in 2007-08 (Pillai,
2008).The productivity of cashew in India is moderate. As
suggested by Bhat et al (2007), keeping in view the changing
global scenario, there is a need to produce cashew at an
internationally competitive price by reducing the cost of
production and increasing production per unit area.
Maharashtra now ranks first in both production and
productivity of cashew in the country.

The average productivity in the state of
Maharashtra is 1.5 t ha-1 against a national average of 800
kg ha-1. This is due to a strong research back-up and
development of high yielding, bold-type hybrid varieties by
Dr. B.S. Konkan Krishi Vidyapeeth, Dapoli, and efforts
made by extension officers of the state department at
transfer of technologies and in popularizing the varieties
developed. However, there is still scope for increasing
productivity to 2.5 t ha-1 with some refinements in
management practices. Among the various factors
influencing cashew yield, the narrow sex ratio is of primary
importance. Therefore, growth regulators are gaining
importance in cashew cultivation for overcoming problems
associated with fruit set, development and, final retention.
Konhar and Mech (1988) reported highest fruit retention in
cashew with Nutron 500 ppm, followed by Etherl 50 ppm
and Planofix 45 ppm. Similarly, Kumar et al (1994) found

Effect of Ethrel® on flowering, sex-expression and yield in cashew

M.S. Gawankar1, R.D. Sawale, S.N. Pawar and S.A. Chavan
Regional Fruit Research Station

 Vengurle - 416 516, India
E-mail: gawankarms@yahoo.co.in

ABSTRACT

A field trial was conducted at Regional Fruit Research Station, Vengurle, Dist.  Sindhudurg, (Maharashtra) to
assess the efficacy of Ethrel® in relation to flowering behavior and yield enhancement in cashew on seven year old
Cashew trees of Vengurle -7 variety during 2008-09. Three sprays of Ethrel® @ 100 ppm, 200 ppm and 400 ppm along
with water spray were given before flushing, after flushing and during fruit-set. Control consisted of no. spray.
Among treatments, Ethrel® @ 100 ppm significantly increased  number of flowering panicles m-2 (12.0), number
of perfect flowers per panicle (52.8), fruit-set m-2 (28.8)

, 
number of nuts per panicle (2.9) and yield tree-1 ( 1.51 kg

tree-1) than control and water spray. Thus, lower concentration of Ethrel® had a beneficial effect on cashew.

Key words : Cashew, Ethrel®, foliar spray, sex ratio, nut yield

Short communication

Ethrel®50 ppm, NAA 25 ppm and 2, 4-D 4 ppm to be most
effective in improving sex ratio and yield. The present
investigation was under-taken to assess efficacy of Ethrel®in
flowering behavior and yield enhancement in cashew.

An experiment was conducted on seven year old
cashew trees of Vengurle-7 (V-7) hybrid grown on lateritic
soils during the fruiting season of 2008-09 at Regional Fruit
Research Station, Vengurle, Dist. Sindhudurg, Maharashtra.
The experiment was designed in Randomized Block Design,
with five treatments and four replications. The climate of
the region is warm and humid, with an annual rainfall of
2916 mm and temperature range of 17.40 C to 32.90 C. The
research center is situated at an elevation of 9 m above
mean sea level.

Three sprays of each treatment were given as
follows: i) before the vegetative flush,    ii) after the vegetative
flush and iii) during fruit-set. Recommended package of
practices was followed uniformly, including plant protection.
Observations were recorded number of laterals before and
after spray, number of flowering panicles per m2, flowering
duration, number of staminate and perfect flowers, fruit-set
per m2, number of nuts per panicle, nut weight and nut yield.
Number of staminate and perfect flowers was recorded
every day till completion of flowering. Sex ratio was
calculated using the formula developed by Abdul Halim
Hassan et al (1988) for calculating sex ratio in oil palm, i.e.,

1All India Coordinated Research Project on Cashew

J. Hortl. Sci.
Vol. 5 (1): 68-70, 2010



69

Sex Ratio = 
flowers ofnumber  Total

flowersperfect  ofNumber 

Results were statistically analyzed following the
procedure given by Panse and Sukhatme (1985).

Various biometric observations were recorded at
specific stages and are presented in Tables 1 and 2.

Effect of Ethrel®spray on growth and flowering

It is evident from data presented in Table 1 that the
mean number of laterals m-2 was significantly higher in the
control (T

1
), water spray (T

2
) and Ethrel®400 ppm (T

5
) than

Ethrel®100 or 200 ppm (T
3
 and T

4
,
 
respectively). However,

after the sprays, water spray (T
2
) was significantly superior

to the other treatments with respect to number of laterals,
followed by control (T

1
) and Ethrel®400 ppm (T

5
) which

were at par with each other and significantly superior over
Ethrel®100 ppm (T

3
) and Ethrel® 200 ppm (T

4
). Further,

regarding growth and flowering behavior in cashew, it was
observed that water spray (T

2
) resulted in better vegetative

growth of trees, which is clear from higher percent increase
in the laterals after spray, and was followed by Ethrel® 100
ppm. However, the concentrations of Ethrel®, viz., 200 and
400 ppm (T

4
 and T

5
) resulted in negligible increase in the

laterals after spray, i.e., 20.5 and 26.5, respectively and
percent increase in laterals in these two treatments was 1.0
and 1.1%, respectively over the control (3.7%). In respect

of flowering behaviour, Ethrel® treatments of 100, 200 and
400 ppm (T

3
, T

4 & 
T

5
) showed a positive impact and produced

significantly higher number of flowering panicles, i.e., 12,
10 and 11m-2, than in control (T

1
) or water spray (T

2
), i.e.,

7.3 m-2.

Effect of Ethrel® spray on sex-expression and yield

The total number of staminate flowers was
significantly higher (629.0) under water spray (T

2
) than in

rest of the treatments (Table 2). This was followed by control
(T

1
) which was also significantly superior to Ethrel®

treatments. Among Ethrel® treatments, Ethrel® 200 ppm (T
4
)

and 400 ppm (T
5
) were at par and were also significantly

superior to Ethrel® 100 ppm (T
3
). Results of the present

study clearly indicated that the number of staminate flowers
was directly related to the number of laterals per m2. Higher
number of laterals under water sprays and control resulted
in higher number of staminate flowers. Ethrel® 100 ppm
(T

3
) produced an average of 52.8 and 400 ppm (T

5
) 48.8

total number of perfect flowers, which was at par but
significantly superior to the remaining treatments. Higher
number of perfect flowers under Ethrel® 100 ppm (T

3
) and

400 ppm (T
5
) can be attributed to the role of Ethrel® in

increasing the number of perfect flowers. Percent increase
in perfect flowers over control was highest under 100 ppm
Ethrel® (T

3
), followed by Ethrel® 400 ppm (T

5
). This is in

agreement with previous investigations in cashew by

Table 1. Effect of Ethrel® spray on growth and flowering in cashew

Sl. No. Treatment Mean  number Mean  number % increasein Mean number   Mean  of
of laterals before of laterals after number oflaterals of flowering flowering

spray/m2 spray/m2 after spray panicles /m2 duration(Days)

1. T
1 

Control (No spray) 27.0 28.0   3.7  7.3 102.5
2. T

2 
Water spray 26.0 32.0 23.1  7.3 101.3

3. T
3 

Ethrel 100 ppm 18.3 19.3   5.5 12.0 101.0
4. T

4 
Ethrel 200 ppm 20.3 20.5   1.0 10.0 104.0

5. T
5 

Ethrel 400 ppm 26.2 26.5   1.1 11.0 102.5
 SEm±  0.8   0.6   0.8     1.9
CD (P=0.05)  2.5  1.9   2.4 NS

NS = Non-significant

Table 2. Effect of Ethrel® spray on sex expression and yield in cashew

Sl. Treatment Total Total % increase Sex ratio Total % % Mean Mean Mean Mean
No. no. of no. of in perfect no. of flowers perfect fruit no. of yield nut

 staminate  perfect flowers flowers staminate flowers set /m2 per nuts (kg/ tree) weight
 flowers flowers over  control panicle (g)

1. T
1 

Control(No spray ) 515.3 19.0 -- 0.04 534.3 96.4 3.6 17.3 1.6 0.88 8.2
2. T

2 
Water spray 629.0 12.8 -33.0 0.02 641.8 98.3 2.0 23.8 1.6 0.93 8.3

3. T
3 
Ethrel  100 ppm 240.0 52.8 178 0.19 292.8 82.0    18.0 28.8 2.9 1.51 8.5

4. T
4 
Ethrel  200 ppm 347.3 20.0 5.3 0.05 367.3 94.6  5.4 18.0 2.0 0.95 7.0

5. T
5 

Ethrel 400 ppm 371.0 48.8 157 0.12 419.8 88.4    11.6 18.0 2.4 0.88 8.2
SEm±   34.2   8.2   38.9   1.5  1.4  1.4 0.2 0.06 0.4
CD (P=0.05) 105.4 25.2 120.2  4.7  4.2  4.3 0.7 0.19 NS

NS = Non-significant

Effect of Ethrel on cashew

J. Hortl. Sci.
Vol. 5 (1): 68-70, 2010



70

Mariappan et al (1995) and Gajbhiye et al (2007). Further,
under water spray, there was a decline in number of perfect
flowers compared to control. Therefore, sex ratio was also
higher under Ethrel® 100 ppm (T

3
), followed by Ethrel® 400

ppm (T
5
). This is in agreement with previous findings of

Mariappan et al (1995) in cashew. Dorajeerao et al (2001)
reported that clones having broader sex-ratio were high
yielders. Ethrel® 200 ppm (T

4
) recorded less number of

perfect flowers (20.0) and higher percentage of staminate
flowers (94.6%), resulting in lower sex ratio. In the present
investigation Ethrel® at 100 ppm might have exert its effect
on sex expression by manipulating endogenous auxin
corresponding the reduction in staminate flowers as reported
by Mariappan et al (1995).

In the case of total number of flowers, water spray
(T

2
) was at par with control and was significantly superior

over Ethrel® treatments. Among Ethrel® treatments, Ethrel®

400 ppm (T
5
) was at par with Ethrel® 200 ppm (T

4
) and

significantly superior to Ethrel® 100 ppm (T
3
). This was

mainly due to higher number of staminate flowers under
water spray and control.  Further, it was observed that the
percentage of staminate and perfect flowers was negatively
correlated and, therefore, higher percentage of perfect
flowers (18%) was observed with Ethrel® 100 ppm (T

3
).

Similarly, in the case of mean fruit set per m2, it was
significantly higher (28.8) under Ethrel® 100 ppm (T

3
) than

in the remaining treatments. This can be attributed to higher
number of perfect flowers and higher percentage of perfect
flowers under Ethrel® 100 ppm (T

3
). The present findings

are in conformity with results of Mariappan et al (1995) in
cashew.

Finally, the mean yield per tree was also significantly
higher under Ethrel® 100 ppm (T

3
) than in the remaining

treatments. This can be attributed to the availability of
significantly higher sinks under Ethrel® 100 ppm (T

3
) in

respect of perfect flowers, fruit set m-2 and number of nuts
per panicle. Gajbhiye et al (2007) and Mohan and Rao
(1995) also reported highest nut yield with Ethrel® spray.
However, the mean nut weight was not significantly
influenced by spray treatments.

ACKNOWLEDGEMENT

The authors are grateful to Dr. B.S. Konkan Krishi
Vidyapeeth, Dapoli, for providing funds and facilities to carry
out this work.

REFERENCES

Abdul Halim Hassan, Mohamad Ali Sekak and Mohd Hanif
Harun. 1988.  Plant growth regulators in Oil Palm,
In: Proceedings of the International Congress of
Plant Physiology, New Delhi, February 15-20, 1988,
I:451– 458

Bhat, M.G., Yadukumar, N. and Nayak, G.M. 2007. Cashew
Research Achievements, Technologies Developed
and Research and Development Strategies. National
Seminar on Research, Development and Marketing
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ICAR Research Complex for Goa, 20-21st November,
2007 pp.3-15

Dorajeerao, A.V.D., Ravisankar, C. and Reddy, M .L. N.
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55-60

Gajbhiye, R.C., Jalgaonkar, V.N., Bendale, V.W. and
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seminar on Research, Development and Marketing
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ICAR Research Complex for Goa, 20-21st November,
2007  pp. 136-137

Konhar, T. and Arun Mech. 1988. Effect of growth
regulators on flowering, fruit set and fruit retention in
cashew. Ind. Cashew J., 18:17-19

Kumar, D.P., Khan, M.M. and Melanta, K.R. 1994. Effect
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Marriappan, S., Prabhakaran, J. and Sambandamoorthy, S.
1995. Effect of growth regulators on sex expression
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L.). The Cashew IX: pp11-13

Mohan, E. and Rao, M.M. 1995. Effect of growth regulators
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Panase, V.G. and Sukhatme, P.V. 1985 . Statistical methods
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Delhi.

Pillai P.B. 2008. Excerpt of speech delivered during 53rd

Annual General Meeting held on 30.09.2008. The
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(MS Received 5 October 2009, Revised 4 February 2010)

Gawankar et al

J. Hortl. Sci.
Vol. 5 (1): 68-70, 2010