Mango (Mangifera indica L.) is a major commercial
fruit crop in many tropical and subtropical countries. India,
the world’s largest producer of mangoes, has 35.46% of its
total area under mango among fruit crops and 28 % of the
total production of fruits. However, productivity of mango
in India is very low compared to other mango-growing
countries, lack of environmental signals for flowering being
a limiting factor for obtaining consistent mango production
in the tropics. An alternative to dependence on the
environmental stimulus for flower initiation is evolving
management strategies substitute for these signals. Several
workers have suggested that foliar feeding of nutrients
directly to the site of metabolism as a substitute for or
supplement to soil application considerably enhanced fruit
yield and quality attributes (Samra et al, 1977; Singh et al,
1994). It has also been recognized that mango leaves absorb
most of the nutrients within 24-72 hrs after spray and,
thereafter, depletion of leaf nutrient content is seen owing
to translocation of N, P and K to actively developing organs
within the plant system (Singh, 2002). Hence, an attempt
was made by us to improve flowering and fruit set in mango
using various nitrogenous chemicals as foliar spray.

An experiment was carried out on 25-year old mango
trees of cv. Alphonso at the orchard of Horticultural College
and Research Institute, Coimbatore, during 2010-2011.  The

Short communication

J. Hortl. Sci.
Vol. 7(2):190-193, 2012

Effect of foliar spray of nitrogenous chemicals on flowering, fruit set and yield in
mango (Mangifera indica L.) cv. Alphonso

R. Sudha1, T.N. Balamohan2 and K. Soorianathasundaram
Department of Fruit Crops

Horticultural College and Research Institute
 Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu

E-mail: rsudhahort@yahoo.co.in

ABSTRACT

Effect of foliar application of various nitrogenous chemicals on flowering, fruit set and yield of mango cv. Alphonso
was studied at the orchard of Horticultural College and Research Institute, Coimbatore, during 2010 - 2011. Maximum
number of flowering shoots (68.7%), number of panicles (7.5/m2), panicle length (31.4cm), number of hermaphrodite
flowers (282.5/panicle), fruit set (17.0%), number of fruits (146.0/tree) and fruit yield (43.8 kg/tree) was obtained
with foliar spray of KNO

3
 at 2% concentration. Higher content of chlorophyll (1.7g mg-1), carbohydrate (14.5g

100g-1) and nitrogen (1.43%) and higher C/N ratio (10.18) were also recorded in plants sprayed with 2% KNO
3
,

followed by 1% KNO
3
.

Key words: Mango, flowering, fruit set, nitrogenous chemicals

trees were under irrigation on clayey loam soil, with available
nitrogen 216.70 kg/ha,

 
available phosphorus 18.32 kg/ha and

available potash 453.60 kg/ha. Trees were spaced at 10m x
10m. The experiment was laid out in Randomized Block
Design with three replications, and a single tree was treated
as a unit/treatment. Treatments included spraying urea @
1% (T

1
) or 2% (T

2
); KNO

3
@1% (T

3
) or 2% (T

4
); NH

4
NO

3

@ 1% (T
5
) or 2% (T

6
); CaNO

3
@1% (T

7
) or 2% (T

8
), and

Control (T
9
). The chemicals were sprayed in morning hours

with a rocker sprayer (after adding Tween-20 as a
surfactant) at fifteen-day intervals from 15th November to
30th December. Data on per cent flowering shoots, number
of panicles/square metre, length of the panicle, number of
hermaphrodite flowers/panicle, fruit set percentage, number
and weight of fruits/tree; chlorophyll, carbohydrate and
nitrogen content and C/N ratio, were recorded as per
standard procedures.

Estimation of per cent shoots flowered was based on
emergence of the flowering panicle in 25 shoots tagged per
tree. Numbers of panicles were counted per square meter
area at five different locations on a tree with the help of a
wooden frame (1m x 1m dimension) and the mean was
arrived at. Length of panicle was measured on ten shoots
and the mean was expressed in centimetres. Number of
hermaphrodite flowers was counted in four panicles at five

1 Division of Horticulture and Forestry, Central Agricultural Research Institute, Port Blair, A & N Islands, India
2 Horticultural College and Research Institute for Women, TNAU, Trichy - 620 009, Tamil Nadu, India



191

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Foliar spray of nitrogenous chemicals in mango

J. Hortl. Sci.
Vol. 7(2):190-193, 2012



192

different locations on the tree during flower opening. Fruit
set was recorded at pea-berry stage on five randomly tagged
panicles. Number of harvested fruits / tree was counted
and their total weight in kilograms (kg) per tree was recorded.
Total chlorophyll content was determined in fresh leaves as
per Yoshida et al (1971) and expressed a mg g-1. Total
carbohydrate content was estimated colorimetrically using
the procedure of Somogyi (1952) and expressed as g
100g-1. Per cent nitrogen content was estimated by Micro
Kjeldahl method of Piper (1966). The ratio of carbohydrate
to nitrogen was calculated. Data collected were subjected
to statistical scrutiny (Panse and Sukhatme, 1967).

Results in Table 1 indicate that percent flowering
shoots increased significantly with application of nitrogenous
chemicals, over the control. Maximum shoot length of
68.2cm was observed in KNO

3
 spray at 2%. Number of

panicles also increased with foliar spray of nitrogenous
chemicals. Highest number of panicles (7.5/m2) was
recorded in trees sprayed with KNO

3
 2%, and the minimum

was seen under control (4.5/m2). Length of panicle was
higher (31.4cm) in KNO

3
 2% treatment. Other nitrogenous

chemicals too increased the length of panicle noticeably over
the control.  Number of hermaphrodite flowers/panicle was
the highest (282.5) in KNO

3
 2% spray, and lowest in the

control (118.0). KNO
3 

spray induced flowering of young
shoots, indicating partial substitution of their maturity
requirement by KNO

3
.

Beevers and Hageman (1969) and Filner et al (1969)
reported ability of KNO

3
 and other nitrate sources as inducing

nitrate reductase in many species. Nitrate reductase is a
key enzyme in nitrate assimilatory pathway for amino acids
synthesis. Methionine has been reported to promote mango
flowering and is a precursor of ethylene (Maity et al, 1972).
Davenport and Nunez-Elisea (1997) stated that KNO

3
-

stimulated flowering of mango is mediated by increased
levels of endogenous ethylene. Potassium nitrate is a
universal rest-breaking agent in deciduous fruit trees (Erez
and Lavee, 1974) that may simply hasten flower emergence
of a differentiated, but dormant, mango bud. Astudillo and
Bondad (1978) reported induction of flowering in ‘Carabao’
mango with KNO

3
.

It is evident from the data that yield / tree differed
significantly among treatments. Sprays of various nitrogenous
chemicals increased fruit set over the control. Though
increased fruit set was observed with KNO

3
 2% (17.0 %),

followed by KNO
3
 1% (16.5 %), the former resulted in

maximum number of fruits (146/tree) as against the control

(102/tree). Highest fruit yield of 43.8kg per tree was
observed with KNO

3
 2% spray, whereas control recorded

least fruit yield of 25.5kg/tree. The next best treatment was
KNO

3
 1% spray (41.4 kg). KNO

3
 treatments were more

effective in increasing fruit yield, which may be attributed
to a higher number of hermaphrodite flowers, fruit set and
number of fruits / tree. Similar report was made by Sergent
et al (1997) in mango cv. Haden.

Plant biochemical parameters were also influenced
by foliar feeding of nitrogenous chemicals. Maximum
chlorophyll content was observed in KNO

3
 2% (1.7mg g-1)

and minimum in control (1.3mg g-1). C/N ratio in leaves
was highest with KNO

3
 2% (10.1), and lowest in control

(10.1). High C/N ratio was probably conducive to floral
induction. Highest carbohydrate content was observed in
trees sprayed with KNO

3
 2% (14.5g 100g-1) compared to

control (11.0g 100g-1). Plants sprayed with KNO
3
 2%

registered higher nitrogen content (1.4%) than the control
(1.0%).  Seasonal changes in carbohydrate and nitrogen
content of mango leaves in relation to flowering have been
reported earlier by Sen et al (1963). The present study
illustrates that KNO

3
 2% foliar spray can improve flowering,

fruit set and yield in mango cv. Alphonso, rather than use of
urea, NH

4
NO

3 
or CaNO

3.

REFERENCES

Astudillo, E. and Bondad, N.D. 1978. Potassium nitrate
induced flowering of ‘Carabao’ mango shoots at
different stages of maturity. Philippines J.Crop Sci.,
3:147-152

Beevers, L.  and Hageman, R.H. 1969. Nitrate reduction in
higher plants. Annu. Rev. Pl. Physiol., 20:492-522

Davenport, T.L. and Nunez-Elisea, R. 1997. Ethylene and
other endogenous factors possibly involved in mango
flowering. Acta Hort., 275:441-448

Erez, A. and Lavee, S. 1974. Recent advances in breaking
the dormancy of deciduous fruit trees. In:
International Horticultural Congress Proceedings,
19:69-78

Filner, P.J., Wray, L.  and Varner, J.E. 1969. Enzyme
induction in higher plants. Science., 165:358-367

Maity, S.C., Maity, S.K. and Sen, P.K. 1972. Effect of
ethylene producing chemicals on growth and flowering
of mango (Mangifera indica L.). Ind. Agri., 16:201-
203

Panse, V.G. and Sukhatme, P.V.  1967. Statistical methods
for agricultural workers. ICAR, New Delhi, pp 108

Piper, C.S. 1966. Soil and Plant Analysis. Hans Publishers,
Bombay, India, pp. 7-299

Sudha et al

J. Hortl. Sci.
Vol. 7(2):190-193, 2012



193

Samra, J.S., Thakur, R.S. and Chadha, K.L. 1977. Effect
of foliar application of urea on yield and yield
parameters of mango. Ind. J. Hort., 34:26-29

Sen, P.K., Sen, S.K. and Guda, D. 1963. Carbohydrate and
nitrogen content of mango shoots in relation to fruit
bud differentiation on them. Ind. Agri., 7:133

Sergent, E., Ferrair, D. and  Leaf, F. 1997. Effect of
potassium nitrate and paclobutrazol on flowering
induction and yield of mango (Mangifera indica L.)
cv. Haden.  Acta Hort., 455:211-220

Singh, J.N., Singh, D.K. and Chakravarthy, D. 1994. Effect
of urea and NAA on fruit retention and physico-
chemical composition of mango (Mangifera indica
L.) cv. Langra. Orissa J. Hort., 22:26-30

Singh, N.P. 2002. Effect of chemicals and plant regulators
on the promotion of flowering and fruiting in mango
cv. Dusehri. Ph.D. thesis, Punjab Agricultural
University, Ludhiana, India

Somogyi, N. 1952. Notes on sugar determination. J. Biol.
Chem., 200:145-154

 Suresh Kumar, P., Reddy, Y.N. and Sri Hari, D. 2003. Effect
of foliar spray of chemicals on flowering and fruiting
of shoots emerging after pruning in mango
(Mangifera indica L.) cv. Baneshan. South Ind.
Hort., 51:7-11

Yoshida, S., Forno, D. A. and Cock, J.I.  1971. Chlorophyll
estimation in rice. Laboratory Manual, IRRI
publications, The Philippines pp. 36-37

(MS Received 13 February 2012, Revised 01 October 2012)

Foliar spray of nitrogenous chemicals in mango

J. Hortl. Sci.
Vol. 7(2):190-193, 2012