Lemon cultivation is becoming exceedingly popular
because of wider utilization of this fruit than any other citrus
fruit. Lemon is popularly seen in kitchen gardens. In India,
fresh lemons are primarily consumed for a cooling effect in
summers. Lemon is widely used in preparation of soft drinks
and possesses special dietary and medicinal value associated
with its high vitamin C content. Lemon oil is among the
most important citrus oils used for flavouring soft drinks,
baked foods, confectioneries, etc. Lemon is also used for
preparing pickles, squashes, jams, jellies, and marmalades.
The plant is free from citrus canker and is endowed with
the trait of bearing fruits in several flushes, thus making it
available throughout the year. Unfortunately, it suffers from
a very serious problem of fruit cracking in summers causing
considerable reduction in marketable yield, leading to a heavy
financial loss to the grower every year. However, application
of growth regulators can help in improvement of quality in
lemon by controlling the intensity of fruit cracking.

In a report on citrus fruit quality, physiological basis
and techniques of improvement, Augusti et al (2002)
concluded that citrus fruit quality was influenced largely by
physiological disorders like cracking, puffing and creasing.
Cracking manifests as a meridian fissure in the peel, usually
developing from the stylar end and reaching the equatorial
zone or, even, extending beyond that. Irrespective of its
origin, the crack develops as a consequence of disruption
between peel and pulp growth. It was found that during the

Improving lemon [Citrus limon (L.) Burm.] quality using growth regulators

Savreet Sandhu
Punjab Agricultural University, Regional Research Station

Bathinda-151001, India
E-mail : savreetz@gmail.com

ABSTRACT

Lemon [Citrus limon (L.) Burm.] is a leading acidic citrus fruit. However, poor fruit quality causes considerable
reduction in marketable yield leading to heavy financial loss to the grower. To combat poor fruit quality, an experiment
was laid out during the fruiting year 2009 with a view to obtain excellent quality lemon at harvest. Plant material for
this investigation was selected from Punjab Government Progeny Orchard & Nursery, Attari, Amritsar. Foliar spray
of NAA (10, 20 and 40ppm)

 
and GA

3
 (5, 10 and 20ppm) was applied twice at an interval of 15 days during the month of

May. Substantial improvement in fruit quality could be achieved with growth regulator treatment. NAA at 40ppm
proved to be the best treatment for managing fruit cracking and improving fruit quality.

Key words: Lemon, Baramasi, fruit cracking, quality, NAA, GA
3

J. Hortl. Sci.
Vol. 8(1):88-90, 2013

Short communication

phase of cell enlargement, if the peel does not restart its
growth when the pulp expansion takes place, the fruit splits.
They found growth regulators to be useful in reducing fruit
cracking as these not only increase peel thickness but also
significantly increase peel resistance to puncturing. They
also observed that repetition of sprays improved this
response. Growth regulator sprays are of utmost importance
when targeting quality in lemon fruits. Therefore, this study
is an attempt to work out the most suitable hormone spray
for improving fruit quality and controlling rind splitting in
lemon.

The plant material for investigation was selected from
Punjab Government Progeny Orchard & Nursery, Attari
(Amritsar), during the year 2009.  In the trial, eight year old
lemon trees of uniform size and vigor, free from diseases
and pests, were selected. The experiment was conducted
in Randomized Block Design. All the treatments were
replicated four times taking a treatment unit as two trees.
Percentage data was analyzed using arcsine transformation.
The experiment consisted of foliar sprays of NAA

 
and GA

3

at various concentrations as shown below:

Treatment details

T
1

- Untreated (Control)
T

2
- NAA (10ppm)

T
3

- NAA (20ppm)
T

4
- NAA (40ppm)



89

T
5

- GA
3
 (5ppm)

T
6

- GA
3
 (10ppm)

T
7

- GA
3
 (20ppm)

Two sprays were applied during May at an interval
of 15 days (first spray on 10th May and the second on 25th

May). The plants received standard fertilizer dose of 75kg
FYM /tree and 350g N/tree) and irrigation at intervals of
10-15 days, as recommended by PAU, Ludhiana.
Percentage of cracked fruits was calculated on the basis of
total number of fruits initially present on the tree. Fruit length
and breadth was measured using Vernier’s Callipers.
Percentage of juice was calculated on fresh weight basis.
Chemical characters like TSS, acidity and ascorbic acid were
measured as per standard procedures of A.O.A.C. (1990).

Data in Table 1 indicate T
4
 (NAA @ 40ppm) to be

the most effective treatment for minimizing fruit cracking
in lemon (to 13.35%). However, Control treatment registered
maximum fruit cracking (37.62%). Reduction in fruit
cracking may be due to the auxin causing enlargement of
cells by increasing elasticity and plasticity of the cell wall
(Yasuda, 1969). Thus, peripheral tissues of the fruit would
have kept pace with growth of cortex resulting in the
reduction of fruit cracking, since, one reason for cracking
in fruits is differential growth rates of the peripheral and
cortex tissues. Peripheral tissues, being senescent and weak,
are highly prone to mechanical stress and cracking.
Therefore reduction in cracking by GA

3
 spray may well be

due to suppression of certain aging processes leading to
increased viability of the peel (Coggins and Lewis, 1965).
Richards et al (2001) reported that growth regulators
improve cell wall flexibility by stimulating synthesis of new
cellulose polymers. Singh et al (2006) also opined that
systematic spray of growth regulators before rind splitting
helps control cracking as growth regulators influence rind

thickness. Garcia-Luis et al (2001) found that application
of growth regulators markedly influenced rind structure,
affecting both cell size and thickness of flavedo, as it is
relevant to cracking. Moreover, growth regulators play a
significant role in peel resistance and plasticity that determine
intensity of cracking.

T
4
 (NAA @ 40ppm) also proved to be the best

treatment for maximizing fruit size (5.5cm length and 5.3cm
breadth) and weight (65.46g) in lemon. On the other hand,
fruits from untreated plants registered minimum fruit size
and weight. A generally accepted opinion is that increase in
fruit size is due to enlargement of the already existing cells,
and auxins are presumed to be responsible for this
enlargement. Hence, application of NAA caused fruit
enlargement by increase in cell size. Fruit elongation and
increase in fruit breadth may be due to cell division initially,
and cell enlargement in the later stages. Similar findings
have been documented by Singh et al (2007) and Bhatia
and Yadav (2005). Fruit weight also exhibited the same
pattern as in fruit size, with treatment T

4 
maintaining its

superiority over other treatments. Singh et al (2007) in aonla,
Kumar et al (2004) in litchi and Josan et al (1995) in lemon
elucidated similar results. There are many reports in literature
suggesting that application of NAA may raise endogenous
auxin levels in the fruit, which favours development of
various parts of the fruit. Thus, increase in fruit size and
juice percentage due to auxin application perhaps led to
increase in fruit weight due to cell expansion. It is also
possible that a developing fruit is an important metabolic
sink, into which nutrients and organic substances from leaves
and other plant parts flow, thereby accumulating in the fruit.
This accumulation of metabolites and water in fruit increases
fruit weight. A direct relationship between endogenous
gibberellin content in developing fruits of orange with their
growth rate was established by Krishnamoorthy (1981).

Improving lemon quality using growth regulators

Table 1. Effect of spraying various growth regulators on fruit cracking and quality in lemon [Citrus limon (L.) Burm.] cv. Baramasi

Treatment Fruit trait

Fruit Fruit Fruit Fruit Juice TSS Acidity Ascorbic acid
 cracking (%) length (cm) breadth (cm) weight (g) (%) (%) (%) (mg/100ml of juice)

T
1

37.62 (37.78) 4.70 4.43 53.67 41.20 7.15 5.05 45.43
T

2
18.22 (25.14) 5.10 4.80 57.30 45.28 7.33 5.70 49.36

T
3

15.30 (22.88) 5.35 5.15 62.20 47.20 7.47 5.70 50.30
T

4
13.35 (21.30) 5.50 5.30 65.46 48.82 7.53 5.56 53.44

T
5

23.45 (28.87) 4.90 4.75 57.13 42.38 7.28 5.40 48.13
T

6
17.58 (24.64) 5.00 4.90 59.06 44.40 7.40 5.50 49.41

T
7

20.55 (26.85) 5.15 4.95 66.20 46.98 7.60 5.62 51.53
CD (P=0.05) 5.85 0.14 0.20 6.60 2.48 0.07 0.05 2.71
CV % 12.29 1.64 2.40 6.17 3.09 0.58 0.54 3.08

Figures in parantheses indicate arcsine transformed values

J. Hortl. Sci.
Vol. 8(1):88-90, 2013



90

All chemical treatments applied in our experiment
produced significant effect on juice content in lemon fruits
compared to the Control. Data clearly depict that fruits
harvested from trees sprayed with 40ppm NAA showed
maximum juice content (48.82%). Higher moisture content
in fruits resulted in higher juice content. Significant increase
in TSS and acidity was recorded with increasing
concentration in the foliar spray. Maximum values for these
parameters were recorded in treatment T

4
, and, the

minimum in trees with no foliar sprays. TSS increased with
every increase in concentration of growth regulators in the
foliar spray. Auxins have been known to be involved in
synthesis of α-amylase which converts starch in sugars and,
consequently, increasing osmotic pressure of the cell which
results in accumulation of water and other solutes. Another
reason may be that sugars get accumulated, or, some
insoluble substances like starch are rendered soluble by
hydrolysis, and thus increase total soluble solids
(Krishnamoorthy, 1981). Increase in acidity could be
attributed to increased osmotic pressure by cell expansion
due to auxins, which lead to accumulation of organic acids.
Work of Josan et al (1995) and Mostafa et al (2005) also
lends support to the present findings. Treatment T

4 
resulted

in maximum ascorbic acid content (53.44%) in fruits.
Minimum ascorbic acid content was recorded in fruits from
untreated trees. Increase in ascorbic acid content may also
be due to the growth regulators increasing osmotic pressure
by cell expansion, thus leading to accumulation of this organic
acid.

Results indicated that foliar spray of NAA @ 40ppm
in lemon substantially reduced cracking losses and resulted
in better fruit quality. Thus, to overcome this serious problem,
a good preventive spray programme is necessary at critical
stage of fruit development.

REFERENCES

A.O.A.C. 1990. Official methods of Analysis of Analytical
Chemists, 15 th Edition (Ed. W. Horowitz).
Association of the Official Analytical Chemists,
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Augusti, M., Martinez-fruentes, A. and Mesejo, C. 2002.
Citrus fruit quality, physiological basis and techniques
of improvement. Agrosciencia, 4:1-16

Bhatia, B.S. and Yadav, R.K. 2005. Effect of foliar spray
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Coggins, C.W. Jr. and Lewis, L.N. 1965. Some physiological
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(MS Received 11 November 2011, Accepted 14 June 2012, Revised 15 September 2012)

Savreet Sandhu

J. Hortl. Sci.
Vol. 8(1):88-90, 2013