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EFFECT OF FOLIAR APPLICATION OF KNO3
ON FRUIT YIELD AND QUALITY IN LITCHI
Thesis
Submitted to the Punjab Agricultural University
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
in
HORTICULTURE (FRUIT SCIENCE)
(Minor Subject: Botany)
By
Divya Pandey
(L-2014-A-86-M)
Department of Fruit Science
College of Agriculture
© PUNJAB AGRICULTURAL UNIVERSITY
LUDHIANA-141 004
2016
CERTIFICATE – I
This is to certify that the thesis entitled, “Effect of foliar application of KNO3 on
fruit yield and quality in litchi” submitted for the degree of M.Sc. in the subject of Fruit
Science (Minor subject: Botany) of the Punjab Agricultural University, Ludhiana, is a
bonafide research work carried out by Divya Pandey (L-2014-A-86-M) under my
supervision and that no part of this thesis/dissertation has been submitted for any other
degree.
The assistance and help received during the course of investigation have been fully
acknowledged.
__________________________
(Dr. Nav Prem Singh)
Major Advisor Assistant Professor
Department of Fruit Science
Punjab Agricultural University
Ludhiana – 141 004 (India)
CERTIFICATE II
This is to certify that the thesis entitled, “Effect of foliar application of KNO3 on fruit
yield and quality in litchi” submitted by Divya Pandey (L-2014-A-86-M) to the Punjab
Agricultural University, Ludhiana, in partial fulfillment of the requirement for the degree of
Master of Science, in the subject of Horticulture (Fruit Science) (Minor subject: Botany) has
been approved by the Student‟s Advisory Committee after an oral examination on the same.
_________________ _______________________
(Dr. Nav Prem Singh) (Dr. Vishal S. Rana)
Major Advisor External Examiner
Senior Scientist
Department of Fruit Science
Dr. YSPUH&F, Nauni
Solan – 173230
Himachal Pradesh
__________________
(Dr. M.I.S. Gill)
Head of Department
___________________
(Dr. Neelam Grewal)
Dean Post-Graduate Studies
ACKNOWLEDGEMENT
First of all, I bow my head to Him, the merciful God almighty for His blessing hand
and bestowing a creative and healthy environment throughout my academic and research
period.
It is my proud privilege to express my deep sense of gratitude and indebtness to my
major advisor Dr. Nav Prem Singh, Department of Fruit Science for his inspiring guidance
and constant encouragement in planning and execution of study and research work, which
helped me to successfully complete the work in time. He had been very kind to me in
extending all possible helps and providing facilities for the completion of the research work
as well as in the preparation of this manuscript. His patience and persistence became an
ideal for me.
Guidance, affection and help in improving this manuscript by the esteemed members
of my advisory committee, Dr. PPS Gill, Horticulturist, Department of Fruit Science , Dr.
(Mrs.) Seema Bedi, Head cum Professor of Botany, Department of Botany, Dr (Mrs.)
Sumanjit Kaur, Assistant Horticulturist, FRS Gangian and Dr. Harminder Singh, Senior
Horticulturist (Dean PGS’ nominee), Department of Fruit Science is highly acknowledged.
I also wish to express my sincere thanks to Dr. MIS Gill, Head, Department of Fruit
Science for providing me necessary facilities during my research work.
It is beyond access to acknowledge in words the unending help and encouragement
received from my mother Smt. Asha Pandey and my father Shri Sudhir Pandey for their
moral support, untiring efforts, infinite love, affection and silent prayers. Unbounded
affection of my lovely brother Anurag Pandey can hardly be expressed in words.
The perky bunch of my friends who made my life lot easier deserve all my gratitude:
Sneha Kumari, Anupam Anand, Tahseen Nazar, Alok Kumar, Shubhra Singh Parmar,
Harsimrat Kaur Gill and Isha Dadhwal were constant source of help of all kinds and made
my task lighter by their pleasant and gracious company and a special bouquet of gratitude to
my friend Shipra Singh Parmar for her inconsistent support and guidance in every phase of
my work.
I feel privileged to express my sincere thanks to field staff of FRS, Gangian and the
laboratory staff of PG, and Post harvest Lab. Department of Fruit Science for providing
necessary cooperation during my research work.
The financial help from ICAR in the shape of Junior Research Fellowship is duly
acknowledged. I feel proud to be a part of PAU, Ludhiana where I learnt a lot and spent some
unforgettable moments of my life. I wish to record my gratitude for any person, my memory
had failed to recall, and who rendered their support in various capacities throughout the
period of the studies.
Place: Ludhiana
Date: (Divya Pandey)
Title of the Thesis
: Effect of foliar application of KNO3 on fruit yield and
quality in litchi
Name of Student the and
admission No.
: Divya Pandey
L-2014-A-86-M
Major Subject : Fruit Science
Minor Subject : Botany
Name and Designation of
major Advisor
: Dr. Nav Prem Singh
Assistant Professor
Degree to be Awarded : M.Sc. (Fruit Science)
Year of award of degree : 2016
Total pages in thesis : 56 + VITA
Name of the University : Punjab Agricultural University,
Ludhiana – 141004, Punjab, India
ABSTRACT
The present investigation was carried out to study the „Effect of foliar application of KNO3 on
fruit yield and quality in litchi‟ during the year 2015-16. Thirty five year‟s old uniformly
grown „Dehradun‟ litchi plants established at MS Randhawa FRS, Gangian (Hoshiarpur) were
sprayed with KNO3 @ 1.0, 1.5 and 2% at three different stages i.e. single spray 10 days after
fruit set (DAFS) (S1); double spray after 10 and 20 DAFS (S2) and triple spray after 10, 20
and 30 DAFS (S3) and the control (water spray). The plants treated with K as foliar feeding
significantly improved fruit pericarp colour, marketable fruit yield and quality attributes over
the control. Increment in fruit yield to the tune of 13.9% was recorded in trees treated with
double spray of KNO3 1% over the control. Fruit weight, size and fruit retention were also
improved with different doses of K as foliar feeding. Fruit colour coordinates estimated in
terms of ‘L‟ value was recorded the highest with one spray of KNO3 1.5% and ‘a’ value also
increased from 17.9 to 18.6 with the increased in dose of KNO3 from 1 to 2 per cent as well as
single spray of KNO3 1.5%, however; ‘b’ colour value was noted maximum with single spray
of KNO31%. Fruit quality characteristics viz. soluble solids content (SSC), SSC/acid ratio and
total sugars were also enhanced with single, double and triple sprays of different
concentrations of K fertilizers over untreated trees. Leaf N and K contents were significantly
higher with foliar feeding of KNO3, however, effect on leaf P content was statistically non
significant. From the present studies, it is concluded that single foliar spray of KNO3 1% after
10 DAFS considerably improved fruit size, fruit weight, pericarp colour, pulp/stone ratio and
fruit yield in litchi cv. Dehradun.
Key words: Litchi, Potassium, Quality, Pericarp Colour
____________________________ ______________________
Signature of the Major Advisor Signature of the Student
Koj pRbMD dw isrlyK : Anwr (punIkw gRynytm AYl.) iksm mRIdulw dy ivkws dOrwn &l dy vwDy Aqy BOiqk-rswiexk pirvrqn dw mulWkx
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: idivAw pWfy AYl-2014-ey-86-AYm
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XUnIvristI dw nwm : pMjwb KyqIbwVI XUnIvristI, luiDAwxw – 141004, pMjwb, Bwrq
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mOjUdw AiDAYn “lIcI iv`c &l dy JwV Aqy guxvqw aupr KNO3 dy iCVkwA dw pRBwv” isrlyK ADIn sMn 2015-16 dOrwn kIqw igAw[ AYm.AYs. rMDwvw AYP.AYs.Awr., gMgIAw (huiSAwrpur) ivKy ie`k swr v`fy kIqy gey lIcI dy pMj swl dy „dyhrwdUn‟ pOidAW aupr v`Ko-v`Kry pVwvW aupr KNO3 @ 1.0, 1.5 Aqy 2% dw iCVkwA Bwv pihlI vwr &l pYx (DAFS) qoN 10 idnW mgroN iehihrw iCVkwA (AYs1); DAFS qoN 10 Aqy 20 idnW mgroN dohrw iCVkwA (AYs2) Aqy DAFS qoN 10, 20 Aqy 30 idnW mgroN iqhrw iCVkwA (AYs3) Aqy kMtrol (pwxI dw iCVkwA) kIqw igAw[ kMtrol dy mukwbly potwSIAm nwl aupcwrq pOidAW dy &l dy bIj koS dy rMg, &l dy mMfIXog JwV Aqy guxvqw mwpdMfW iv`c ArQpUrn suDwr hoieAw[ kMtrol dy mukwbly KNO3 @ 1 pRqISq dy iekihry iCVkwA nwl aupcwrq pOidAW dy &lW dy JwV iv`c 14% vwDw hoieAw[ iesy aupcwr nwl &l dy Bwr, Awkwr Aqy &l dI AvDwrn smr`Qw iv`c vI suDwr hoieAw[ KNO3 @ 1.5 pRqISq dy do iCVkwAvW nwl, „L‟ AMk dy ilhwz nwl AWklq kIqy gey &l dy rMg dy smwXojk sB qoN vDyry pwey gey Aqy &l pYx qoN mgroN hr 10 idnW dy AMqrwl aupr KNO3 @ dI imkdwr iv`c 1 qoN 2 pRqISq q`k vwDw krn nwl „a‟ AMk iv`c 17.9 qoN 18.6 q`k dw vwDw drj kIqw igAw[ hwlWik KNO3 @ 1 pRqISq dy iekihry iCVkwA nwl „b‟ AMk sB qoN vDyry drj kIqw igAw[ iesdy ault, KNO3 @ 1 pRqISq dy dohry iCVkwA nwl aupcwrq pOidAW iv`c kormw „b‟ AMk sB qoN vDyry sI[ Ax-aupcwrq pOidAW dy mukwbly pOtwSIAm Kwd dIAW v`Ko-v`KrIAW GxqwvW dy iekihry, dohry Aqy iqhry iCVkwA vwly pOidAW iv`c &l dI guxvqw dy mwpdMf ijvyN ik GulxSIl Tol sm`grI (SSC), SSC/AYisf Anupwq Aqy ku`l SUgr dI imkdwr iv`c vwDw hoieAw[ KNO3 dy iCVkwA nwl p`qy iv`c nweItRojn Aqy pOtwSIAm dI imkdwr ArQpUrn qOr qy vDyry sI, hwlWik, p`qy iv`clI &ws&ors dI imkdwr aupr koeI vI ArQpUrn pRBwv nhIN vyiKAw igAw[ mOjUdw AiDAYn dy nqIijAW qoN ieh q`Q swhmxy Awey ik lIcI dI iksm dyhrwdUn iv`c &l pYx dy 10 idnW mgroN KNO3 1 pRqISq dy iekihrI iCVkwA nwl &l dy Awkwr, Bwr, pYrIkwrp rMg, gudw/igtk Anupwq, Aqy &l dy JwV iv`c ArQpUrn suDwr hoieAw[
mu`K Sbd: lIcI, pOtSIAm, guxvqw, bIj koS rMg
__________________ _______________ pRmu`K slwhkwr dy hsqwKr ividAwrQI dy hsqwKr
CONTENTS
CHAPTER TOPIC PAGE (S)
I INTRODUCTION 1 – 3
II REVIEW OF LITERATURE 4 – 16
III MATERIAL AND METHODS 17 – 22
IV RESULTS AND DISCUSSION 23 – 43
V SUMMARY 44 – 46
REFERENCES
VITA
47 – 56
LIST OF TABLES
Table No. Title Page No.
1 Effect of foliar application of KNO3 in fruit weight (g) in litchi cv.
Dehradun
24
2 Effect of foliar application of KNO3 on fruit retention in litchi cv.
Dehradun
25
3 Effect of foliar application of KNO3 on fruit length (mm) in litchi cv.
Dehradun 26
4 Effect of foliar application of KNO3 on fruit diameter (mm) in litchi
cv. Dehradun 26
5 Effect of foliar application of KNO3 on aril weight (g) in litchi cv.
Dehradun
27
6 Effect of foliar application of KNO3 on fruit stone weight (g) in litchi
cv. Dehradun
28
7 Effect of foliar application of KNO3 on fruit pericarp weight (g) in
litchi cv. Dehradun
29
8 Effect of foliar application of KNO3 on Pulp/stone ratio in litchi cv.
Dehradun
29
9 Effect of foliar application of KNO3 on fruit volume (cc) in litchi cv.
Dehradun
30
10 Effect of foliar application of KNO3 on specific gravity in litchi cv.
Dehradun
31
11 Effect of foliar application of KNO3 on fruit colour in litchi cv.
Dehradun
32
12 Effect of foliar application of KNO3 on soluble solid content (%) in
litchi cv. Dehradun
35
13 Effect of foliar application of KNO3 on juice titratable acidity (%) in
litchi cv. Dehradun
36
14 Effect of foliar application of KNO3 on SSC/TA ratio in litchi cv.
Dehradun
37
15 Effect of foliar application of KNO3 on total sugars (%) in litchi cv.
Dehradu
38
16 Effect of foliar application of KNO3 on reducing sugars (%) in litchi
cv. Dehradun
39
17 Effect of foliar application of KNO3 on non reducing sugar (%) in
litchi cv. Dehradun
39
18 Effect of foliar application of KNO3 on fruit yield (Kg/tree) in litchi 40
Table No. Title Page No.
cv. Dehradun
19 Effect of foliar spray of KNO3 on nitrogen content (%) in leaves of
litchi cv. Dehradun
41
20 Effect of foliar spray of KNO3 on phosphorus(%) content in leaves of
litchi cv. Dehradun
42
21 Effect of foliar spray of KNO3 on potassium content (%) in leaves of
litchi cv. Dehradun
42
LIST OF FIGURES
Fig. No. Title Page No.
1 Effect of foliar application of KNO3 on aril weight (g) in litchi cv.
Dehradun
27
2 Effect of foliar application of KNO3 on pulp/stone ratio in litchi cv.
Dehradun
30
3 Effect of foliar application of KNO3 on „L’ colour coordinate of litchi
cv. Dehradun
33
4 Effect of foliar application of KNO3 on „a’ colour coordinate of litchi
cv. Dehradun
34
5 Effect of foliar application of KNO3 on „b’ colour coordinate of litchi
cv. Dehradun
34
6 Effect of foliar application of KNO3 on litchi leaf K content 37
CHAPTER I
INTRODUCTION
Litchi (Litchi chinensis Sonn.) recognized as “Queen of the fruits” is an important sub
tropical evergreen fruit crop belongs to the family Sapindaceae. It is native of south China
and was introduced by the end of 17th century to explore the possibilities of litchi cultivation
in India due to available of conducive temperature and climatic requirements. Litchi crop is
widely distributed in the tropics and warm subtropics of the world. It is a highly priced fruit
and is used in the form of fresh fruit and preparation of value added products i.e. RTS,
squash, dry nut etc. It performs best in the regions possessing cool dry frost-free winters and
warm summers with high rainfall and humid climatic conditions (Menzel 1983). Litchi fruits
are rich in sugar contents and it varies from 6.74-18.0%, juice acid content 0.20 to 0.64% in
the form of malic acid and also possesses citric acid, succinic acid, levulinic acid, phosphoric
acid, glutamic, malonic and lactic acids. It also contains 40.2-90 mg vitamin-C/100 g edible
portion, 0.9% protein, 0.3% fat, 0.42% pectin and 0.7% minerals (Ca, P, Fe). Litchi skin is
rich in insoluble fiber, which prevents rectum cancer, diabetes and heamorrhoids. Wang et al
(2010) reported that water soluble alcohol extracted from litchi skin significantly inhibited in
vitro growth of human hepatoma cells and suppressed cancer development particularly
effective in the suppression of breast cancer. Litchi skin contains free radical scavenging
compounds like ascorbic acid, glutathione, carotenoids, polysaccharides (Yang et al 2006);
and phenolic substances including flavonoids (flavonols and anthocyanins) and phenolic
acids. Besides, litchi seeds are responsible for reducing blood sugars and lipids; and promote
the functioning of the liver.
In India, annual litchi fruit production to the tune of 0.57 mt and productivity 7.02
MT/ha is obtained from an area of 82,330 ha (Anonymous 2015). It is cultivated on 1988 ha
with annual production of 26520 MT and productivity 15.1 Mt/ha in Punjab state
(Anonymous 2015) and approximately 90.3 per cent of the total area under litchi cultivation is
mainly situated in sub mountane districts i.e. Gurdaspur, Pathankot, Hoshiarpur, Ropar, SBS
Nagar and Patiala. To ensure high economic productivity and retain the optimum nutrients in
the soil at the desired level, correct doses of manures and fertilizers must be applied on the
basis of long term fertilizer experiments and choose of reliable diagnostic tools (Bhargava et
al 1993). Generally, fruit plants require seventeen mineral elements for various physiological
processes whereas N and K are required in sufficient amount for the production of quality
fruits. It is postulated that 10 MT litchi fruits annually remove nearly 67 kg N, 16 kg P2O5 and
73 kg K2O from the soil. It is, therefore, essential that litchi trees should be supplied with
adequate nutrients for sustainable fruit production as limited supply of macro and micro
nutrients in the soil is responsible for poor fruit yield and quality (Menzel and Simpson 1987).
2
Zhang et al (2004) opined that nutrition plays a significant role in improvement of litchi
flowering, fruiting and productivity. Litchi nutrition management should be based on
monitoring of leaf and soil nutrients status; and fertilizer doses are likely to be adjusted on the
basis of tree canopy and yield potential (Menzel et al 1992, Menzel 2001). Roy et al (1984)
studied the correlation between „Bombai‟ litchi fruits with leaf N, P and K contents and
reported that fruit yield was related to leaf N content at the time of flowering and harvest and
with leaf K content at fruit harvest.
It has been also observed that leaves absorbed most of the nutrients within 24-72
hours after spray and thereafter depletion of leaf nutrients content was noted due to
translocation of N, P and K to the active developing organs in plant system (Singh et al 2007).
Leaf N, P and K contents are directly correlated with the availability of respective nutrients in
the soil profile and their absorption by the fruit plants (Dhillon and Malhi 1991). Yang et al
(2015) reported that fruit-strengthening potassium fertilizer (40% appropriately) should also
be applied during the fruit enlargement period to promote litchi fruit expansion and to
improve „Ziniangxi‟ litchi yield and quality.
Potassium is one of the essential nutrient required for numerous biochemical and
physiological processes vital to plant growth, yield, quality and stresses. In horticultural
crops, potassium improves fruit yield, fruit size, soluble solids concentrations, ascorbic acid,
colour, shelf life, and shipping quality (Geraldson 1985, Lester et al 2007) as it concerns with
the process of phosphorylation; transportation of photo assimilates from source tissues via the
phloem to sink tissues, enzyme activation, turgor maintenance, transpiration, photosynthesis
and stress tolerance (Usherwood 1985, Pettigrew 2008). Likely, Menzel and Kirby (2001)
also reported that potassium enhances cell hydration and its deficiency causes tissue
dehydration; and act as the main osmotic solute in the plants for stomatal functioning.
Potassium is involved in the translocation of sugars, formation of carbohydrates and regulates
root hydraulic conductivity and provides resistance against pest, diseases, drought and frost
stress (Imas and Bansal, 1999). Southwick et al (1996) suggested that K intake from foliar
feeding is more efficient than soil application, where soil cation interactions hinder the
availability of soil K. However, tree metabolic functions should be improved and ineffective
rate of respiration also reduced by using an appropriate K fertilizer, which is in turn essential
for the improvement of the tree‟s carbohydrate supply, accumulation level, fruit setting and
yield (Deng et al 1994).
In litchi cv. Rose Scented under Uttranchal conditions, Kumar and Kumar (2004)
confirmed that three pre harvest foliar sprays of „Multi-K‟ (1.0 %) @ 15, 30 and 45 days after
fruit set considerably produced fruits with higher TSS (18.0%), total sugars (12.4%),
TSS/acid blend ratio (28.6), juice ascorbic acid content (34.9 mg / 100 g pulp) and lower
(0.63%) juice acid than the control. Two pre-harvest foliar sprays of Polyfeed (19:19:19) on
3
litchi plants at the interval of 15 and 45 days after fruit set effectively produced fruits with
maximum fruit weight, aril weight, juice content, TSS, total sugars, reducing sugars, TSS/acid
ratio, sugar/ acid ratio and ascorbic acid and minimum acidity content (Singh et al 2007).
Singh and Kumar (2008) concluded that an increase in N, P, K, Cu, Zn and Fe in the leaves
corresponding to the Polyfeed application appeared to be correlated positively to a certain
extent. Nutrients applied through Polyfeed as foliar sprays were readily absorbed by the plant
system for the efficient functioning of the metabolic processes of the plant.
The relationship between the leaf nutrients and fruit quality attributes showed positive
relationship between leaf K, anthocyanin content and titratable acidity, leaf P and pericarp ho,
leaf N and leaf Ca and fruit firmness (Sivakumar and Korsten 2007). The adequate
information on foliar applications of nutrients as supplement to soil application on fruit
sensory parameters in different litchi cultivars is lacking under Punjab conditions. Therefore,
the present investigation was planned to study the effect of different spray timings and KNO3
(15:0:46) concentrations as foliar feeding in „Dehradun‟ litchi cultivar with the following
objectives:
i. To elucidate the effect of nutrients as foliar application on fruit yield and quality
attributes.
ii. Correlation studies between leaf nutrients with fruit quality parameters.
CHAPTER II
REVIEW OF LITERATURE
The literature pertaining to the present investigation „Effect of foliar application of
KNO3 on fruit yield and quality in litchi has been reviewed under following heads:
2.1 Effect on fruit size
2.2 Effect on fruit colour
2.3 Effect on fruit weight
2.4 Effect on fruit quality
2.5 Effect on fruit yield
2.6 Effect on nutrient content
2.1 Effect on fruit size
Foliar feeding of Potassium has played the crucial role in the enhancement of fruit
size in various fruit crops (Reitz and Koo 1960, Embleton et al 1966, Gill et al 2012) as it
improves fruit quality through enhancing fruit colour, size and juice flavour (Tiwari 2005).
Boman (2001) revealed that foliar application of KNO3 at different stages (II and III) in fruit
development cycle effectively increased fruit size. Higher doses of K fertilizers significantly
improved the net photosynthesis in „Golden Delicious‟ apples under salt stress (Schreiner and
Lüdders 1996). Under sub-tropical conditions of Punjab, Gill et al (2012) studied the effect of
single, two or three foliar sprays of KNO3 and K2SO4 (1.0, 1.5, 2.0%) on fruit size and quality
in „Patharnakh' pear and concluded that fruit size was increased significantly in all the
treatments over the control, however, maximum improvement was recorded with three sprays
of KNO3 @ 1.5 % when applied at 15 days intervals starting from full bloom. Miller et al
(1999) reported that fruit size was better with treatment of KNO3 (5 %) + 2, 4-D (20 ppm)
applied after nine weeks from full bloom. Likewise, Bhatia et al (2001) also reported an
increase in guava fruit size with foliar application of K2SO4 (0.5, 1.0, 1.5%), ZnSO4 (0.5,
0.75, 1.0%) and H3BO3 (0.3, 0.5, 1.0%). In two years experiment on Fairlane‟ nectarines,
Ruiz (2006) evaluated the effect of soil application of KNO3, K2SO4 and KCl (300 kg K2O
ha-1
and recorded considerable enhancement in fruit diameter with all the treatments over the
control. The effect of K2SO4 (0.3%) as foliar application on apple cultivars „Lambourne‟,
„Liberty‟ and „Florina‟ prior to harvesting was studied by Doroshenko et al (2005) and
observed that leaves soluble carbohydrates contents was decreased by 7-15% and fruit size
increased 1.2-1.9 times within 20 days after their application which significantly improved
marketable size and fruit production. In „Bartlett‟ pear, Kumar and Chandel (2004) noted
positive correlation between leaf K content with fruit length, fruit diameter, weight, total
soluble solids and fruit yield.
5
Peach trees cv. „Early Coronet‟ sprayed twice with KNO3 (0.1, 0.2 %) combined with
either NAA (0 or 5 mg/L) or iron (0, 30 or 60 mg Na Fe EDDHA/litre) after one month of
fruit set and treatments NAA 5 mg/L, 0.2 per cent KNO3 and 60 mg/L NaFe EDDHA gave
the best results in terms of shoot dry weight, total chlorophyll, fruit number, fruit length, fruit
diameter and total carotene (Al-Bamarny et al 2010). Achilea (2000) reported that single
spray of higher dose of KNO3 enriched with soluble phosphates (13-2-44, N-P-K) with
adjuvant on „Jaffa‟ oranges (fruits diameter 18-22 mm) substantially increased percentage of
fruit size (above 75 mm diameter) by 75 per cent. Shelf life of stored fruit was also enhanced
due to marked increase in rind potassium content by 0.44 per cent (in dry matter). Elsabagh
(2012) concluded that spraying date palm cv. „Deglet Nour‟ bunches after six week from
pollination with KNO3 or K2SO4 considerably increased fruit size, fruit length and fruit
diameter as compared to the control. Hegazi et al (2011) reported that foliar application of
KNO3 (4 %) on Olive cv. „Picual‟ after final fruit set or pit hardening stage noticeably
improved fruit size for two seasons over the control. Foliar and soil applications of K2SO4 and
K2O considerably increased fruit and flesh weight, length and diameter in „Seweda‟ date palm
(Awad 2014).
In a study in „Kinnow‟ (Citrus reticulata Blanco) mandarin, Ullah et al (2012) and
Ashraf et al (2013) reported that fruit weight, length and flesh weight had increased when
fruits were sprayed with Borax 0.4 %, K and ZnSO4. Foliar application of potassium silicate
(8 ml l-1
) significantly increased weight, length, diameter and fruit volume (Lalithya et al
2014). Sarrwy et al (2012) concluded that foliar applications of KNO3 (1.5%) + Zn (0.5%) on
„Balady‟ mandarin had shown the best results in terms of fruit physical characteristics (fruit
length, diameter, volume and specific gravity). Yadav et al (2014) reported that foliar
application of KNO3, K2SO4, KH2PO4 and KCl (1, 2 %) in „Banarasi‟ and „Karaka ber
cultivars improved fruit retention, fruit size, weight, pulp/stone ratio with the application of
K2SO4 (2%). An increase in fruit weight, length and diameter was noted with the application
of K on „Red Delicious‟ apples (Rashid et al 2008).
Soil application of Potassium carbonate and citrate significantly improved fruit length
and diameter over the control in mango „Zebda‟ (Taha et al 2014). Similarly, Abd El-Razek et
al (2013) reported that foliar application of K2O 25%, Mg 0.5%, Zn 0.5%, salicylic acid 25%,
L- ascorbic acid 0.01%, Riboflavin 0.01% (2 %) during full bloom and two weeks after fruit
set on mango notably improved fruit weight, length, circumference, pericarp weight and pulp
per cent. Mukadam and Haldankar (2013) revealed that foliar application of KNO3 (3%) at
fruit set and 20 days after fruit set statistically improved fruit length and diameter in Karonda.
Khayyat et al (2012) postulated that pomegranate tree sprayed with KNO3 (250 mg l-1
) had
shown the markable effect on fruit length and diameter over the control. Ashkevari et al
(2010) reported that soil application of K (1500 g tree-1
) in citrus plants significantly
6
increased fruit length and diameter in comparison to other treatments including the control.
Berry size in grapes was significantly improved with the soil application of K2SO4 (300
g/vine) in combination with nitrogen than the control (Amiri et al 2007).
2.2 Effect on fruit colour
Usherwood (1985) observed that K nutrient improves fruit colour, vitamin C content
and soluble solids in citrus crops (Koo 1985, Menzel 1997). Gill et al (2012) concluded that
foliar applications of K2SO4 in comparison to KNO3 treatments in „Pathernakh‟ pear cultivar
were more effective for the enhancement of fruit brightness over the control. Higher ‛L’, „a‟
and „b‟ coordinates was noticed with the application of K2SO4 (2.0%). Likewise, El-Gazzar
(2000) stated that K as foliar feeding in „Anna‟ apples significantly improved apple skin
colour. In „Perlette‟ cultivar, Chanana and Gill (2008) reported that two applications of K2SO4
(1.0 %) at one week after fruit set and veraison stage, significantly improved berry colour;
however, berries sprayed with K2SO4 had amber gold colour in comparison to amber colour
in untreated berries. In contrast, Ritenour et al (2003) suggested that low doses of K had
increased number of green fruits. Abd El-Razek et al (2011) reported that higher dose of K
(330 kg K2O/ha) increased anthocyanins content in „Crimson seedless‟ grapes.
Yang et al (2015) conducted an experiment to study the changes in K, Ca and Mg
contents of pericarp and its effects on the pericarp's colour in litchi cv. Ziniangxi and found
that higher total pericarp Ca content improved the pericarp's redness and it would be used to
estimate the fertilizers application for the future application. Sivakumar and Korsten (2007)
reported a positive correlation between leaf potassium and anthocyanin content in litchi cv.
‟Mauritius‟. Similarly, Yang et al (2008) reported that potassium fertilization improved fruit
appearance, pigmentation index and ‛L’, ‛a’ and ‛b’ of fruit tip and fruit body in ‛Yanguang‟
nectarines. Likewise, foliar application of potassium + glucose on „Flame seedless‟ grapes
significantly improved the berry skin colour (Kelany et al 2011). Lester et al (2005) observed
that improvement of fruit colour is attributed to the effects of potassium on carbohydrate
influx as optimum K level enhanced phloem loading, nutrient transportation and unloading of
sucrose.
2.3 Effect on fruit weight
In „Balady‟ mandarin trees grown on sandy soils of Egypt, Ebrahiem et al (1993)
advocated that application of KNO3 (0.5 to 1.0 %) significantly improved vegetative growth,
increased leaf K and N, fruit weight and yield. Sharma et al (1990) suggested that fruit weight
and pulp percent in mango cv. „Langra‟ were the best with the foliar sprays of Urea 4% and
KNO3 3% during flowering over the control. In apple cv. Anna, the highest fruit weight was
obtained with the spray of K2SO4 (1.5%) (Kilany and Kilany 1991). On contrary, Okada et al
(1994) observed decreased in fruit size in „Satsuma‟ mandarins when leaf K content was
below than 0.7 per cent. Josan et al (1995) concluded that maximum fruit weight in
7
‛Baramasi‟ lemon was observed with the foliar application of K2SO4 (10.0%) followed by
K2SO4 (8.0 %). In ‛Satsuma‟ mandarin, Koseoglu et al (1995) reported that leaf K content had
shown positive correlation with fruit weight.
Application of potassium nitrate (4 %) and urea (1%) in „Tommy Atkins‟ mangoes
resulted in higher fruit set, fruit number and fruit weight. Nitrogen supplement from KNO3
and urea sprays might be the reasons for the increase in the quantitative parameters of fruit
yield (Yeshitla 2004). Mostafa and Saleh (2006) observed positive effect on leaf mineral
content, fruit set and fruit weight in citrus trees with the spray of different K formulations due
to their role in osmoregulation of cell vacuoles and maintain of the equilibria (Wani and
Khajwall 1997). Ruiz (2006) conducted five years experiment on nectarine and observed
significant effect of potassium on fruit weight due to greater flux of potassium from leaves to
fruit. Abd-Allah (2006) reported that fruit weight of „Washington Navel‟ Orange was
significantly increased with Ca chelate + K2HPO4 treatment as compared with the other
treatments and the control. Khayyat (2012) reported that foliar application of Borax 1500 and
2500 ppm + K2SO4 (1, 2 %), K2SO4 (1, 2 %) and potassium citrate (3 %) on date palm cv.
„Shahany‟ substantially enhanced fruit length, diameter and flesh weight over the control.
Similarly, Ben Mimoun et al (2009) observed that spray of K2SO4 significantly increased fruit
weight in peach and plum cultivars. Application of SADH and K nutrient effectively
increased the edible fruit proportion and maximum aril percentage was observed with SADH
(400 ppm) followed by KNO3 (1.5%). Application of potassium (4.5 kg tree-1
) on
„Bartamoda‟ date palm produced highest bunch weight, fruit weight and moisture content and
also increased leaf contents of N, K, Ca, Mn and Cu (Osman 2010). Likewise, improvement
in the fruit weight in ‛Yanguang‟ nectarine with K fertilization was noted by Yang et al
(2008).
Foliar application of K2SO4 (3.0%) increased fruit weight in ‛Black Star‟ plums and
‛Royal Glory‟ peaches and suggested that higher efficiency of foliar sprays than fertigation,
especially sprayed during stage-III of fruit development when potassium demand was more
by the fruits (Ben-Mimoun et al 2009). Pathak and Mitra (2010) noted maximum fruit weight
and aril recovery when potassium @ 600 g was applied in two equal splits at 15 days after
fruit set and 30 days before flowering. Influence of plant growth regulators and mineral
nutrients on physico-chemical characteristics in „Rose Scented‟ litchi cultivar was studied by
Lal et al (2010) and observed that tree sprayed with KNO3 (1.5%) and Ca(NO3)2 (2%)
produced the highest fruit weight to the tune of 20.41 and 20.37 g, respectively.
The applications of KNO3 (2%) at bud emergence, full bloom and pea stages
significantly increased initial fruit set/panicle, fruit retention (%) and fruit weight (Stino et al
2011). Sarrwy et al (2012) reported that foliar application of KNO3 on “Balady” mandarin
significantly increased fruit physical characteristics (fruit length, diameter, weight, volume
8
and specific gravity). Elsabagh (2012) concluded that KNO3 or K2SO4 sprayed on date palm
cv. „DegletNour‟ bunches, six week after pollination increased fruit retention (%), fruit
weight, flesh weight and seed weight as compared to the control. In Kinnow (Citrus reticulata
Blanco), increase in fruit weight, length and flesh weight was observed with foliar application
of borax (0.4%), K and ZnSO4 (Ullah 2012; Ashraf et al 2013). In date palm cv. „Seweda‟,
Awad (2014) observed that foliar application and soil treatment of K2SO4 and K2O
substantially increased fruit and flesh weight.
2.4 Effect on fruit quality
Foliar sprays of K nutrient significantly improved fruit quality in pear (Hudina and
Stampar 2002) and Kinnow mandarin (Gill et al 2005) and is acclaimed as the quality nutrient
for the crop production (Usherwood 1985). Singh and Tripathi (1978) found an improvement
in fruit quality characters in „Banarasi‟ and „Langra‟ mangoes with three foliar applications of
KNO3 (3%) and NaH2PO4 (6%) after panicle emergence. Singh et al (1979) reported the
highest TSS, sugars and ascorbic acid and lowest acidity in „Langra‟ mangoes with the spray
of Urea 4 per cent. Koo (1985) reported that citrus fruit removed significantly more K than
any other nutrient from the soil and it improved citric acid, ascorbic acid, sugar acid ratio and
soluble solids content. Potassium is essential in the formation and translocation of
carbohydrates which in turn improved the fruit quality. Likewise, Martin-Prevel (1989)
suggested that K is closely associated with fruit size, firmness, soluble solids, sugars and
organic acids, juice content, flavour, however, excess application of N adversely affected the
quality attributes in apples and pears. Application of N, P, K, Ca, Zn, B and Mn in apple
increased soluble solids, fructose, sucrose, malic acid and citric acid (Stamper et al 2002).
Vijayalakshami and Srinivasan (2000) concluded that mango cv. „Alphonso‟, application of
KNO3 (1%) greatly increased TSS from 7.67 to 14.33 per cent total sugars from 9.25 to 12.71
per cent, sugar/acid ratio from 27.96 to 43.58 and also decreased acidity from 0.33 to 0.29 per
cent. In a study on guava cultivar „L- 49‟, Bhatia et al (2001) suggested that organoleptic
rating was the highest with K2SO4 (1.5%); whereas, total soluble solids and sugars was found
in H3BO3 treatments.
Boman (2001) reported that post-bloom and summer foliar application of K on
‛Valencia‟ oranges produced larger fruits and higher soluble solids, as compared to non-
spayed trees. Likely, foliar application of N, P, K, Ca, Zn, B and Mn in apple proportionally
increased soluble solids, firmness, fructose, surcrose, malic acid and citric acid (Stamper et al
2002). Hudina and Stampar (2002) noted that foliar application of P and K (15% P2O5, 20 %
K2O, 0.1% Mn, 0.1% B and 0.1% Mo) in pear cv. „Williams‟ notably increased fruit glucose,
sorbitol, soluble solids, malic acid, citric acid and K contents. Hunsche et al (2003) observed
that soil application of K increased fruit mass, tritratable acidity, red colour and potassium
content while decreased flesh firmness. In „Sardar‟ guava, Dutta (2004) reported that
9
treatments viz. KNO3, K2SO4 and KCl noticeably increased fruit juice, total soluble solids,
total sugars, and non- reducing sugar. Potassium fertilization exerted a significant role on
fruit yield and quality in peach cultivars „Spring Time‟ and „Red Haven‟ (Chatzitheodorou
et al 2004).
In mango cv. „Alphonso‟, foliar application of K2SO4 (2.0%) substantially increased
fruit juice total sugars and non-reducing sugars (Kumar et al 2006). However, maximum
(10.9%) TSS and total sugars (7.25%) was obtained with the application of K2SO4 (1.0%) as
noted by Dutta and Banik (2007) in „Sardar‟ guava cultivar. Chanana and Gill (2008) reported
that foliar application of K2SO4 improved total soluble solids and decreased fruit acidity in
grapes cv. 'Perlette'. Similarly, higher K supply considerably increased TSS and decreased
juice acidity in „Temprallino‟ grapes (Martin et al 2004). Foliar application of K2SO4 (2.0%)
in mango cv. Alphonso substantially increased total sugars and non reducing sugars (Kumar
et al 2006). In 'Lambourne', 'Liberty', „Florina‟ cultivars, Doroshenko et al (2005) sprayed
K2SO4 (0.3%) prior to harvesting the fruits and found that leaves soluble carbohydrates
content was decreased by 7-15 % and increased by 1.2-1.9 times in fruits within 20 days after
their application and also improved market quality, fruit size, soluble solids and yield.
Takano et al (2007) found positive correlation between fruit TSS and leaf potassium content
in ‛Shimizu-Hakuto‟ peaches. In litchi cv. „Mauritius‟, leaf potassium had shown positive
relationship between anthocyanin, titratable acidity, firmness, skin colour and consumers‟
acceptability (Sivakumar and Korsten 2007). Fruit inner qualities of ‛Yanguang‟ nectarine in
terms of soluble solids content, soluble sugars, sugar to acid ratio, vitamin C and fruit
appearance was significantly improved with K fertilizers (Yang et al 2008).
In litchi fruits cultivar „Rose Scented‟, Singh et al (2007) found that two pre-harvest
foliar sprays of Polyfeed (1%) on trees after 15 and 45 days from fruit set, significantly
produced maximum fruit weight, aril weight, juice content, TSS, total sugars, reducing
sugars, TSS/acid ratio, sugar/ acid ratio and ascorbic acid with minimum acidity content. In
guava cv. Sardar, Dutta and Banik (2007) noted maximum (10.85 brix) TSS and total sugars
(7.25 %) with the application of K2SO4 (1.0%). In apple cv. „Red Delicious‟, application of K
notably increased total soluble solids (TSS), however, fruit acid content was decreased
(Rashid et al 2008). Chanana and Gill (2008) reported that foliar application of K2SO4
substantially improved total soluble solids and decreased the fruit acidity in „Perlette‟grapes.
Pathak and Mitra (2010) noted the lowest (0.31%) fruit acid content, highest (64.0)
Brix/acid ratio and ascorbic acid content (49.67 mg 100 g aril-1
) when K (600 g) was applied
in two equal splits at 15 days after fruit set and 30 days before flowering as higher leaf-K
content was found associated with increased photosynthetic activity, stomatal conductance
and water use efficiency. The highest cost: benefit ratio of 1: 38.26 was also recorded by
application of 600 g potassium per plant per year. Pathak et al (2013) stated that higher rates
10
of both P and K markedly reduced the fruit acidity, however, increased TSS/acid ratio and a
decrease of fruit acidity were more pronounced with the addition of B and S along with P and
K. Fruits from the plants receiving 400 g P2O5, 1050 g K2O, 140 g S and 7 g B/ plant/year had
shown ascorbic acid content to the tune of of 44.62 mg 100 g aril-1
.
Amiri et al (2010) reported that Potassium alone or in combination with N or Mg
increased berry SSC. Ashkevari et al (2010) stated that soil application of K (1500, 3000 g
tree-1
) considerably improved quality attributes in citrus crop. Likewise, foliar application of
K improved fruit firmness, sugar content, ascorbic acid, beta-carotene due to increase in soil
K contents (Lester et al 2007). Foliar application of K comparatively improved TSS content
due to its role in translocation of sugar from leaves to fruits, which resulted in better quality
fruits in apple (Shirzadeh and Kazemi 2012). Gill et al (2012) applied one, two and three
foliar sprays of KNO3 and K2SO4 (1.0, 1.5, 2.0%) on fruit quality in pear cv. „Patharnakh' and
observed that three applications of K2SO4 substantially increased fruit firmness; however,
soluble solids content (SSC) were increased with various K treatments and number of
applications; and the highest value was recorded with K2SO4 (2.0%).
The effect on fruit TSS and ascorbic acid was more pronounced with the application
of K2SO4 (2%) as compared to other potassium compounds and the control in „Banarasi
Karaka‟ ber cultivar (Yadav et al 2014). However, fruit juice acid content had shown reverse
trend being maximum (0.25 %) in the control, followed by 1 per cent KH2SO4 and KCl (1%)
and minimum (0.18 %) in K2SO4 (2%). Bhatia et al (2001) noted that fruit quality in guava
was improved with foliar application of K2SO4 (0.5, 1.0, 1.5%), zinc sulphate (0.5, 0.75,
1.0%) and H3BO3 (0.3, 0.5, 1.0%).
2.5 Effect on fruit yield
In a study conducted on pear cv. „Bartlett‟, Fisher et al (1959) applied potassium in
the form of either K2SO4 or KCI and considerably increased in fruit yield was observed in
trees received K2SO4 fertilizer (2.9 bushels/tree) as compared to KCI (2.0 bushels/tree). Koo
and Reese (1972) reported that improvement in fruit yield with the application of KNO3 is
related to production of bigger fruit size and higher number of fruits. Embleton et al (1973)
suggested that both soil and foliar K2SO4 application considerably increased fruit yield, size
and reduced creasing in „Valencia‟ oranges. Significantly higher fruit yield in ‛Valencia‟
oranges with foliar application of KNO3 (5.0 per cent) over the control was observed by
Fouche et al (1977); however, increase in fruit yield was due to more supply of nitrogen with
the application of KNO3. In a two-year trial in ‛Valencia‟ oranges grown in Letsitele district
of South Africa, Duplessis (1983) compared the effect of KNO3 (2, 4%) and K2SO4 (4%)
sprayed 2 or 3 times during October and December or KCl as soil application @ 5.0 kg/tree.
The best results in both the years were obtained with KNO3 4.0 % and fruit yield was
increased from 144 kg/tree to 178 kg/tree in the first year and 155 kg/tree to 197 kg/tree in the
11
second year of experimentation. Menzel and Simpson (1987) found that foliar deficiencies of
N, P, and K decreased litchi fruit set as well as its development and yield. In contrary,
Orphanos et al (1986) did not get any effect of K application on fruit yield in ‛Valencia‟
oranges. Ray and Mukherjee (1989) confirmed that leaf N and P content before flowering and
nitrogen after harvesting were positively and significantly correlated with fruit yield. Sharma
et al (1990) reported that sprays of Urea (2 or 4%) and KNO3 (1.5 or 3.0 %) during flowering
significantly enhanced fruit yield in mango cv. „Langra‟. They also noted that Urea (2 or 4%)
as foliar feeding increased the number of fruits per panicle than untreated trees. Santosa et al
(2014) concluded that litchi trees applied with NPK, compost, and micronutrients
significantly increased leaf N, P and K concentrations, fruit yield, green colour of leaves,
biomass of new shoots and foliar area. In „Le Conte‟ pear cultivar, Gobara (1998) sprayed
plants with various mineral elements and higher yield was obtained with sequestered iron
followed by potassium sulphate. Dhillon et al (1999) reported that bunch yield was increased
with the increase of potassium doses up to 200g in grapes under sub tropical conditions of
Punjab.
Foliar application of K from different sources (KH2PO4 or KNO3) effectively
enhanced fruit set and yield in oranges and mandarin trees (Abd El-Migeed et al 2000). Mitra
et al (2002) found that application of potassium (5.0 kg/ha) during petal fall and thereafter at
4 weeks intervals significantly improved fruit yield in pear cultivars „Conference‟ (32.1 t/ha)
and Williams (29.4 t/ha). In a study related with apple (Malus pumila) in northeast of
Slovenia, Stampar et al (2002) reported that foliar nutrition comprised the addition of
macronutrients or micronutrients significantly influenced fruit yield and quality; and it was
doubled and the mean of five years production reached to the tune of 70.0 t/ha. In guava cv.
„L-49‟, Dutta (2004) noted the effect of different sources of potassium (K2SO4, KNO3 and
KCl) on fruit yield and physio-chemical qualities and K sprayed at higher doses (K2SO4
2.0%) increased the fruit yield. Foliar feeding of potassium in grapes cv. „Thompson seedless‟
as potassium thiosulphate (2 ml/l) at veraison to harvest stage increased fruit yield and quality
of berries (Saleem et al 2004). Application of KNO3 (4.0%) and urea (1 %) in mango cv.
„Tommy Atkins‟ had increased fruit set, fruit number and fruit weight. Nitrogen supplement
from KNO3 and urea spray might be the reason for the increased in the quantitative
parameters of fruit yield (Yeshitla 2004). Doroshenko et al (2005) revealed that different
apple cultivars „Lambourne‟, „Liberty‟ and „Florina‟ were sprayed with 0.3 per cent K2SO4
i.e. 40 days prior to harvesting considerably increased the fruit yield. Mostafa and Saleh
(2006) revealed that either girdling alone or with sprays of KNO3 (2.0 per cent) on ‛Balady‟
mandarin significantly increased fruit yield tree-1
. Trees treated with potassium markedly
improved fruit yield in „Valencia‟ and „Hamlin‟ oranges as compared to the control (El-
Fangary 1998; Mostafa and Saleh 2006).
12
In litchi cv. „Mauritius‟, Sivakumar and Korsten (2007) studied the effect of various
fertilizers i.e., potassium nitrate, calcium nitrate, ammonium sulfate and urea on the
nutritional status and fruit quality parameters. They found that the highest fruit yield was
recorded when plants were fertilized with the higher dose of KNO3 (3.0 %). Furthermore,
application of KNO3 increased yield and fruit set as compared to other treatments. It was
concluded that the higher fruit yield which was recorded after application of KNO3 as
compared to ammonium sulfate and urea and these were ascribed to higher fruit set. El-Sherif
et al (2008) stated that potassium treatments significantly increased fruit yield as compared to
the control in plum cv. „Golden Japanese‟. Sotiropoulos et al (2010) revealed that by
increasing N doses after 2nd
and 3rd
years of experiment, leaf N concentration was increased
but only where dose of KNO3 was significantly higher in apple cv. „Starcrimson‟.
Dinesh et al (2009) concluded that 600g N, 300g P and 600g K plant-1
year-1
is the
most appropriate and sustainable dose for getting good vegetative growth and fruit yield in
„Allahabad Safeda‟ guava under hot humid conditions of east coastal region. Harhash and
Abdel-Nasser (2010) stated that „Khalas‟ date palm bunches were sprayed with 2 per cent K-
citrate at the pre-bloom or bloom stages significantly increased fruit set, yield and; fruit macro
and micro-nutrients content. In litchi cv. Bombai it has been reported that excessive
nitrogenous fertilizers often promote vegetative flush; however, high leaf K content in the
month of November - December found to depress vegetative growth and induce more
flowering (Mitra and Sanyal 2010). Kainth and Awasthi (2010) studied the effect of seven
different levels of K (400, 500, 600, 700, 800, 900 and 1000g K2O tree -1
year -1
) on tree
growth, fruit yield and quality in apple cv. „Starking Delicious‟ and observed that fruit yield
was increased when fertilizer was applied up to 800g K2O during 2007 and up to 700g K2O
during 2008 and the results were statistically significant with each other. In a study related
with litchi cv. „Bombay‟, Pathak and Mitra (2010) studied three levels of potassium (400, 600
and 800 g/plant/year) applied at three different times (15 days after fruit set and 30 days
before flowering, and 15 days after fruit set and 60 days before flowering) and obtained the
maximum yield (91.84 kg/plant/year) when K (600 g/plant/year) was applied in two splits at
15 days after fruit set and 15 days after harvest.
The application of KNO3 4% twice during growth season in Olive crop considerably
enhanced nutritional status, improved vegetative growth, reduced fruit drop and increased the
productivity (Hegazi et al 2011). In a study related to enhance fruit yield in mangoes showed
that application of KNO3 @ 2 per cent at bud emergence, full bloom and pea stage increased
initial fruit set, number of panicles, fruit retention (%), fruit weight and had shown positive
effects on fruit quality as well as physical and chemical fruit properties (Stino et al 2011).
Karim and Neven (2012) revealed that GA3, CPPU and K substantially increased fruit yield in
citrus cv. „Nova‟ tangerine. Likewise, K (0.25% K2SO4) as foliar feeding, improved fruit set,
13
fruit retention, yield and quality parameters in citrus (Yasin et al 2012). In a two years trial on
„Washington‟ navel orange (Citrus sinensis) trees in Egypt, Abd El-Rahman et al (2012)
sprayed KNO3 @ 2, 4 and 6 per cent at different timing and stages i.e. full bloom and fruit
diameter of 1 and 2-5 cm or both and obtained the highest fruit yield (53%) with single spray
at full bloom with 4 per cent concentration.
Afiqah et al (2014) studied the effect of KNO3 applied three times on mango shoots
@ 1, 2 and 5 % and found that dose of 2 per cent was the best which significantly increased
fruit yield and number of fruit tree-1
. In Huidong under South China conditions, Yang et al
(2015) reported that fruit yield and planting benefits in litchi cv. „Feizixiao‟ initially increased
and then subsequently decreased with the increase in the rate of K2O/N ratio. Litchi had the
highest yield and plant benefit when the ratio of K2O to N ranged from 1.0 to 1.2 and this
ratio is recommended for the main litchi production areas in China.
2.6 Effect on nutrient content in leaves
Foliar application of nutrients can supply essential elements directly to the foliage
and fruits any time when rapid responses may be desired. Sen et al (1974) observed that
nitrogen controls the uptake of P and K and beyond a certain level of plants develop
deficiency of K but not of P in „Langra‟ mango trees. Singh (1980) reported higher level of
total nitrogen in the defoliated shoots of „Dashehri‟ mangoes against the fruited shoots.
Narwadkar and Pandey (1989) observed preferential movement of phosphorus through the stem
to the differentiating buds. Translocation of phosphorus from leaves to the fruit was observed to
occur most rapidly during early fruit set, resulting in the conclusion that phosphorus
translocation may be involved in the control of alternate bearing. Dutta and Dhua (1999) found
that higher leaf mineral contents of N, P, K, Zn and Mn with the sprays of potassium at different
levels on „Himsagar‟ mango trees. The relationship between leaf nutrients and fruit quality
attributes in litchi cv. Mauritius had shown positive relationships between leaf potassium (K)
and anthocyanin content and titratable acidity (TA); leaf phosphorus (P) and pericarp h°, leaf
nitrogen (N) and fruit weight; leaf calcium (Ca) and fruit firmness (Sivakumar and Korsten
2007).
Chen et al (2010) conducted an experiment to determine NPK content in shoot
sections and concluded that the changes in NPK contents were different in litchi. The NPK
contents in the last flush shoot decreased significantly at the pre-blossoming stage, while in
the primary flush shoot it hardly changed. After harvest, P content in the leaves and stalks of
the primary flush shoot and the secondary flush shoot decreased significantly, while that in
the tertiary flush shoot showed no changes. Change patterns in NPK contents in different
organs or tissues were different. NPK contents in the phloem were relatively stable. Contents
of NK in leaves significantly decreased to low values at the pre-heading stage and the pre-
blossoming stage, and the contents of PK in stalks also significantly decreased at the two
14
stages. After harvest, the N contents in leaves and stalks rose while PK contents in them
continued to decline. The N content in xylem significantly increased at the pre-heading stage,
but the PK contents significantly decreased, and only P content significantly declined at the
pre-blossoming stage, while N P contents significantly rose after harvest. The change patterns
of the contents of different element were different. In the five major phenol phases of litchi,
the K content in different organs basically declined with development, while N and P contents
fluctuated. The NPK contents in different organs were different. The NPK content was the
highest in leaves t; P content was the highest in the xylem and leaves; N and K contents were
the highest in xylem, and K content was the most abundant in the stalks and phloem.
Joshi et al (2010) studied the effect of leaf age on various nutrient elements like N, P,
K, S, B and Zn and concluded that tissue maturity significantly influenced nutrient content in
litchi leaves. The contents of N, P and K was found higher in the immature leaves as
compared to matured leaves while sulphur, boron and zinc were observed to be higher in
matured leaves when compared to immature ones. Leaf K and fruit potassium content were
increased during fruit development stages and reduction in leaf Ca content and fruits was
noted with the application of potassium (Ernani et al 2002). Kwong and Fisher (1962)
reported that potassium fertilization as K2SO4 on ‛Jerseyland‟ peach increased leaf K content
and decreased leaf Mg content. Soil application of potassium as K2SO4 (1.5-2.0 kg/tree) had
not produced any effect on leaf N and P, while K, Fe, Zn and Mg was increased (Attala et al
2007).
Singh et al (2010) observed that leaf N content was recorded the highest (1.86%) in
„Kasba‟ litchi and the lowest was recorded in „Longia‟ litchi (1.42%). Leaf P content was
highest in „Shahi‟ (0.13%) and „Rose scented‟ (0.13%) and lowest in „Kasba‟ (0.07%) and
„Bedana‟ (0.07%) cultivars. Leaf K content was highest in „Dehrarose‟ (0.83%) and lowest in
„Kasba‟ (0.56%). Leaf S and Ca content was recorded highest in „Bedana‟ (0.33% and 1.00%)
while lowest in „Shahi‟ (0.27%) and „Deshi‟ (0.75%) respectively. „Kasba‟ litchi cultivar
recorded highest (0.63%) leaf Mg content while the lowest in „Late Bedana‟ (0.46%) and
„Longia‟ (0.46%). Among micronutrients, highest leaf Fe, Mn, Zn, Cu and B contents was
recorded for „Kasba‟ (197.60 ppm), „Longia‟ (155.13 ppm), „Dehradun‟ (29.75 ppm), „Green‟
(31.50 ppm) and „Kasba‟ (30.50 ppm) respectively while the lowest in „Late Bedana‟ (92.57
ppm), „Purabi‟ (125.77 ppm), „Deshi‟ (20.38 ppm), „ Purabi‟ (22.13 ppm) and „Ajhauli‟
(18.72 ppm), respectively.
In ‛Valencia‟ oranges, application of K had not shown any significant effect on leaf N
and P, but significant increased leaf K content which in turn caused reduction in leaf Ca and
Mg contents (Bakr et al 1980). In apple cv. „Golden Delicious‟, Komoso and Szewczuk
(2002) reported that application of potassium (KCl, KNO3 and K2SO4) markedly increased
leaf K content and reduced leaf Fe content. Leaf N and Ca contents decreased with the
15
application of KNO3. In apricot cv. „Cataloglu‟, Ozturk et al (2006) showed that foliar
application of potassium nitrate (1.0%, 1.5%, and 2.0%) increased leaf K content, but higher
concentrations of KNO3 did not show any affect on leaf K content and suggested that
potassium absorption by leaves is limited and absorption potency is less than the roots. Foliar
application of KNO3, Agriphos (P 33%, K 28%), Chelan-K, Silene-K on „Andross‟ peaches
significantly increased macro nutrient (N, P, K) content of leaves over the control
(Sotiropoulos et al 2010).
Foliar sprays of KCl, K2SO4, KNO3, K2CO3 and KH2PO4 on olive cv. „Picual‟ were
effective in increasing leaf K concentration (Restrepo-Diaz et al 2009). K+ increases the
uptake of NO3- and K
+ function as a carrier for NO3
- during its absorption by plants.
Grapevines cv. „Tempranillo‟ treated with the higher doses of N or K (200 g N/vine or 120 g
K2O/vine) had shown the highest leaf 3.07 % N and leaf 0.83 % K as compared with the N
doses; 0 and 50 g N/vine (N-content was: 2.90 % and 2.93 % respectively) and compared
with the K doses; 0 and 60 K2O g/vine i.e K content was: 0.78 and 0.75 %
respectively(Martin et al 2004). Foliar application of K i.e. KH2PO4 or K2HPO4 or KNO3 on
„Balady‟ mandarin significantly raised leaf N, P and K contents (Mostafa et al 2005). El-
Fangary (1998) reported that foliar application of K had positive effect on leaf mineral
content, fruit set and yield in citrus trees. In a study related with ‛Balady‟ mandarins,
Ebrahiem et al (1993) reported that foliar application of potassium nitrate at 1.0 per cent
increased leaf K and N contents and decreased leaf P, Mg, Ca, Fe, Zn and Cu contents.
Chadha and Singh (2009) conducted an experiment to standardize leaf position for
sampling in „Shahi‟ and „China‟ litchi cultivars under acidic silt loam soil of Jharkhand state.
Leaflets were collected from four positions from the terminal apex downward i.e., first, third,
fifth and seventh pair were analysed for nutrient content. The variation in leaf macro nutrient
concentrations (N, P, K, S, Ca and Mg) was observed whereas N, P, K contents gradually
decreased while leaf Ca and Mg contents was increased from the first to third leaf position in
both the cultivars. Leaf S content did not show any consistent trend with respect to leaf
positions. In case of micro-nutrients (Fe, Mn, Zn and Cu) the leaf Fe and Mn content
increased gradually from first leaf position to fifth leaf position while Zn and Cu content of
leaf decreased from first leaf position to third and remained almost stable thereafter. Hence,
leaflets from 3rd to 5th position starting from uppermost fully opened leaf could be
considered as the best leaf for sampling study. The 5th pair of leaflets from the growing tips
showed lower levels of N, P, K, Zn, Cu but higher levels of Ca, Mg, Mn and Fe than the first
pair while leaf S was not influenced significantly for both the cultivars.
Available of soil N content was maximum and the values were 0.001628, 0.001821
and 0.001820% when fertilized was applied @ 600 g K2O in two splits at 15 days after fruit
harvest in the months of July, September and December respectively (Pathak et al 2013). The
16
application of higher doses of potassium increased leaf K content i.e 0.98 per cent in the
month of May. The leaf K content noted maximum with highest dose of potassium (800
gK2O/tree/year) except in the month of April (0.99%) and June (1.00%) when it was found
maximum with 600 g K2O and in May (1.08%) with 400 g K2O/tree/year. Boron content of
leaf decreases with increased dose of potassium application. In Huidong under South China
conditions, Yang et al (2015) conducted field experiments to determine the annual dynamic
changes of element contents in litchi leaves and the effects of the potassium and nitrogen ratio
(K2O/N ratios: 0.6, 0.8, 1.0, 1.2, and 1.4) on the fruit yield in litchi cv. „Feizixiao‟ planted in a
typical acidic upland orchard
Three years field experiments were conducted by Yang et al (2015) to determine the
effects of application ratios of K2O/N: 0.6, 0.8, 1.0, 1.2 and 1.4 on mineral element contents
in fruits of litchi, and their correlation. With the increased of K2O/N ratio, K and B contents in
the epicarp of litchi was decreased; the K content in the endocarp was decreased firstly then
increased; the K content in the pulp, the Ca contents in the epicarp, endocarp and pulp, the B
content in the endocarp were all increased firstly and then decreased; and the Ca content in
the core was gradually increased. Likwise, K/Ca, Mg/Ca,(Mg+K)/Ca and K/B ratios in the
epicarp and endocarp were decreased firstly and then increased, and the Ca/B ratio in the
epicarp increased. The K content in the endocarp is significantly negatively correlated with
the healthy fruit rate, and the Ca content in the epicarp and B content in the endocarp had
positive correlation or significant positive correlation with the healthy fruit rate. The K
contents in the epicarp and endocarp were significantly and positively correlated with the
relative leakage rate of the peel, while the Ca content in the epicarp was significantly and
negatively correlated with the relative leakage rate of peel. The K contents in the epicarp and
endocarp had significant positive correlations with the PPO and POD activities of the peel,
while the Ca contents in the epicarp and endocarp are significantly negatively correlated with
the PPO and POD activities of the peel. The K/Ca, Mg/Ca,、(Mg+K)/Ca and K/B ratios in
the epicarp and endocarp were negative or significantly negative correlated with the healthy
fruit rate, while positive or significantly positive correlated with the relative leakage rate, the
PPO activity and POD activity of the peel. Reasonable potassium and nitrogen application
ratios (K2O/N) not only improved the epicarp and endocarp Ca/B ratio, but also reduced the
epicarp and endocarp K/Ca, Mg/Ca, (Mg+K)/Ca, and K/B.
17
CHAPTER III
MATERIAL AND METHODS
The present investigations to study „Effect of foliar application of potassium nitrate on fruit
yield and quality in litchi‟ conducted at MS Randhawa, PAU-Fruit Research Station, Gangian
(Dasuya) Hoshiarpur situated in the sub mountaneous zone of Punjab at 30o
9‟ to 32o
5‟ N
latitude and 75o 32‟ to 76
o 12‟ E longitude receives average annual rainfall of 1000 mm and
nearly 75 per cent of the total rainfall is received in July to September whereas 15 per cent
during January and February. The material and methods employed during the investigation
are described as under.
3.1 Plant material
The present studies were carried out on 35 years old fully mature and healthy plants of litchi
cultivar „Dehradun‟ planted at 9.0 m x 9.0 m. The uniform cultural practices were given to all
the trees as per recommendation of „Package Practices for Fruit Crops’ Punjab Agricultural
University. Trees were applied with 60 Kg well rotten farm yard manure, 2.25 Kg
Superphosphate (16.0 % P2O5) and 0.6 kg Muriate of Potash (60 % K2O) during December.
However, nitrogen in the form of 1.6 Kg Urea (46 % N) was splitted into two equal halves,
where half of the recommended dose was added in early February i.e. before flowering and
other half in April after the fruit set (Anon 2015). The experimental site was situated in the
sub-mountane zone of Punjab (India) between latitude of 310
N and longitude of 750E at an
elevation of 248.9 m above the mean sea level. This region receives annual rainfall nearly
600-800 mm, where 75 per cent of the total rainfall is received during months of July to
September and 15 per cent in the winter months from December to February.
3.2 Experimental design and treatments
The experiment was layout by Factorial Randomized Block Design (FRBD) and trees were
(in addition to soil application of recommended doses of fertilizers) sprayed with different
concentrations of KNO3 (15:0:46) i.e. 1.0 %, 1.5%, 2.0 % and the control (Water spray) (T1,
T2, T3 and T4, respectively) at three different sub treatments (stages) i.e. 10 days after fruit set
(DAFS) (single spray), 10 and 20 DAFS (double spray) and 10, 20 and 30 DAFS (triple
spray) (S1, S2 and S3, respectively). Each treatment was replicated four times. In litchi cultivar
Dehradun, fruit set was observed on 25th April, 2015 and subsequently trees were sprayed at
the ten days interval from fruit set depending on the basis of respective treatment. The plants
were sprayed with Foot sprayer during early morning hours after dissolving calculated dose of
respective treatment in 75 litre of water and Tween 20 (0.01%) sticker was used as a spreader.
3.3 Experimental details
The treatments applied were as shown below:
T1S1 Single spray of KNO3 @ 1.0 per cent after 10 DAFS
18
T1S2 Double sprays of KNO3 @ 1.0 per cent after 10 and 20 DAFS
T1S3 Triple sprays of KNO3 @ 1.0 per cent after 10, 20 and 30 DAFS
T2S1 Single spray of KNO3 @ 1.5 per cent after 10 DAFS
T2S2 Double sprays of KNO3 @ 1.5 per cent after 10 and 20 DAFS
T2S3 Triple sprays of KNO3 @ 1.5 per cent after 10, 20 and 30 DAFS
T3S1 Single spray of KNO3 @ 2.0 per cent after 10 DAFS
T3S2 Double sprays of KNO3 @ 2.0 per cent after 10 and 20 DAFS
T3S3 Triple sprays of KNO3 @ 2.0 per cent after 10, 20 and 30 DAFS
T4 Control (Water spray)
3.4 Observations recorded
The fruit samples from litchi cultivar „Dehradun‟ were harvested randomly at physiological
maturity, whereas, leaf samples to estimate nutrients concentrations after fruit harvest were
collected from the middle of the shoot in the end-June. The fruit and leaf samples were
analyzed for various physico-chemical characteristics at PG Laboratory and Nutrition
laboratory, respectively in Department of Fruit Science, Punjab Agricultural University,
Ludhiana. The observations recorded were as under:
3.4.1 Fruit physical characters
3.4.1.1 Fruit size
The length and diameter of ten fruits picked randomly from each replication was measured
with the help of digital Vernier‟s Callipers and average was calculated in „mm‟.
3.4.1.2 Average fruit weight
Weight of ten fruits was recorded in each treatment with the help of electronic balance. The
mean fruit weight was expressed in „g‟.
3.4.1.3 Fruit Volume
Fruit volume was measured using a calibrated measuring cylinder of 1litre volume and filled
with tap water. Initial level of water was noted. Ten randomly harvested fruits were dipped in
the measuring cylinder with water. The displacement caused by the fruits was again recorded
and the difference in the displacement of water level from initial to final was noted as „ml‟.
3.4.1.4 Specific gravity of fruit
Volume of the fruits was measured by water displacement method and specific gravity was
obtained by dividing the fruit weight by volume of water displaced.
3.4.1.5 Fruit colour
Colour of the whole litchi pericarp was measured by a Hunter Lab Colorimeter, DP-9000
standard model (Hunterlab Associates Laboratory, Inc., Reston, VA). The “L” scale ranges
from no reflection, i.e., black (L = 0) to perfect diffuse reflection, i.e., white (L = 100). The
„a‟ scale ranges from negative values for green to positive values for red, and the „b‟ scale
ranges from negative values for blue to positive values for yellow. Hunter colour parameters
19
(L, a, b) at four arbitrary positions on the circumference of the litchi fruit were recorded and
average was worked out.
3.4.2 Chemical characters
3.4.2.1 Total soluble solids
The juice of ten fruits from each replication was extracted and strained through muslin cloth.
Total soluble solids content of juice were determined with the help of Erma hand
refractometer in terms of degree Brix (%). The values of total soluble solids were then
corrected 20°C with the help of temperature correction chart (AOAC 1990).
3.4.2.2 Total titratable acidity
Two ml of strained juice was diluted to 20 ml with distilled water and then titrated against 0.1
N NaOH solution using phenolphthalein as an indicator. The end point was noted with change
in colour from colourless to light pink. The acidity was calculated in terms of anhydrous
malic acid as follows:
0.0067 x Volume of NaOH used
Acidity (%) = x 100
Volume of juice taken
3.4.2.3 TSS/Acid ratio
TSS/acid ratio was calculated by dividing the value of total soluble solids with that of the
corresponding total titratable acidity.
3.4.2.4 Total sugars
The estimation of total and reducing sugars was done by using method suggested by Lane and
Eynon (AOAC 1990). 10 ml of fresh juice was taken in beaker and lead acetate was added to
precipitate the extraneous material. Further potassium oxalate was added to remove the excess
of lead acetate. Then the solution was filtered through a filter paper and the obtained filtrate
was diluted with distilled water upto 100 ml. This aliquot was further used for total sugars and
reducing sugars estimation. In 25 ml of aliquot, add 5 ml of 60 per cent concentrated HCl and
the solution was left for acid hydrolysis for 24 hours at room temperature. The solutions were
heated for 10 minutes using water bath until temperature rose to 68oC in 10 minutes. It was
titrated with NaOH 40 per cent and later on with NaOH 10 per cent to neutralize the excess of
HCl and thereafter 0.1 N NaOH was used just near to neutralization point. Fehling solution A
and B (5 ml each) was titrated with the above produced neutralized solution using methylene
blue as an indicator. Appearance of brick red colour indicated the end point. The per cent total
sugars were calculated by the following formula:
Total sugars (%)=
0.05
x
Dilution made (ml)
X
Final volume made (ml)
x 100 Volume of
filterate used (ml)
Volume of juice
taken (ml)
Volume of filterate
taken (ml)
20
3.4.2.5 Reducing sugars
To determine the reducing sugars, 10 ml of boiling Fehling solution (5 ml each of
Fehling solution A and B) was titrated against the aliquot solution using methylene blue as an
indicator. The appearance of brick red colour indicated the end point. The per cent reducing
sugars were calculated by the following formula:
Reducing sugars (%) =
0.05
x
Dilution made (ml)
x 100 Volume of filtrate
used (ml)
Volume of juice
taken (ml)
3.5 Leaf nutrient analysis
3.5.1 Collection and preparation of leaf samples
To estimate foliar nutrients, leaf samples from 5 to 8 months old shoots were
collected just before spray in the month of April and after fruit harvest. Leaf samples were
taken from the mid terminal shoots at random from all sides of the trees and at a height of 5-7
feet from the ground level. Each sample comprised 50 leaves taken randomly and put into the
paper bags and were brought to laboratory. They were thoroughly washed, first with ordinary
water then with 0.1N HCl and finally rinsed with the distilled water. After placing the leaves
in the shade these were dried in electric oven at 60°C for 48 hours. The dried samples were
ground in the Willey mill fitted with all components of stainless steel to pass through 40 mesh
sieves. These ground samples were stored in a butter paper bags and used later for analysis of
different nutrients.
3.5.2 Estimation of Nitrogen
To determine the nitrogen, 0.5g of ground sample was digested with 8-9 ml of
concentrated H2SO4 along with digestion mixture in Kel Plus Nitrogen Estimation System. In a
digestion tube, half gram of powdered sample was taken. Four to five gram of the catalyst
mixture consisting of 250 g of K2SO4 with 50 g CuSO4 and 5 g metallic selenium (50:10:1) was
added to the digestion tube. Digestion tube was heated in the digestion block up to temperature
4100C and the end point of digestion is achieved when samples turn colourless or light green.
3.5.2.1 Distillation
The tube containing digested sample was transferred to the distillation apparatus. As
the distillation begins, the digested sample got diluted with distilled water and subsequently
40% NaOH was poured into the distillation tube. In 150 ml conical flask, 10 ml of 4% boric
acid was taken and two indicators were used. In distillation apparatus, digested samples were
heated by passing steam. Ammonia liberated due to the addition of alkali gets collected in 4%
boric acid. The boric acid consisting of ammonia was further utilized for titration.
21
3.5.2.2 Titration
The boric acid distillate in a conical flask was titrated with 0.1 N H2SO4. The end point
of titration was determined with the change of colour from bluish green to permanent pale
pink and leaf N per cent was calculated by
14 x Normality of acid x 100
Nitrogen (%) =
Sample weight x 1000
3.5.3 Digestion for the estimation of phosphorous and potassium
For estimation of P and K, 0.5 g of sample along with 8-9 ml of di-acid mixture
consisting of nitric acid (HNO3) and per-chloric acid (HClO4) in the ratio of 4:1 were taken
in the digestion tube. The mixture was allowed to stand overnight and then digested.
Initially temperature was kept low and was increased gradually. The end point of digestion
was reached when fumes started emerging out of the digestion tubes and solution
became colourless. Tubes were then removed from the digestion unit and were allowed to
cool. After cooling, the contents were diluted with double distilled water and filtered. The
volume was made up to 100 ml with double distilled water after filteration.
3.5.3.1 Estimation of Phosphorous
Phosphorous was estimated by Vanado-molybdo phosphoric yellow colour method as
described by Chapman and Pratt (1961).
3.5.3.2 Nitric acid vanadate-molybdate reagent
In a beaker containing distilled water, 25 g of ammonium molybdate was dissolved.
Separately, 1.25 g of ammonium metavanadate was dissolved in 300 ml boiling water in
another beaker. The solution was cooled and 250 ml of concentrated nitric acid was added
and solution was again cooled at room temperature. Gradually, both the solutions were
mixed and final volume was made to one litre with distilled water.
3.5.3.3 Colour development
Five ml of digested sample was taken in 25 ml volumetric flask and 1-2 drops of
2,4- dinitrophenol indicator were added. Then add 4N Na2CO3 solution drop wise till the
appearance of yellow colour. Afterwards 6N HCl was added drop wise till yellow colour
disappeared. Afterwards, 2 ml of 6N HCl was added in excess to get required pH 4.8
followed by addition of 5 ml of vanadate-molybdate reagent. Volume was made to 25 ml
with distilled water and allowed to stand for 30 minutes for colour development.
3.5.3.4 Phosphorous standard curve
50 ppm stock solution was made using 10000 ppm standard solution. From this 50
ppm solution 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 and 5.0 ml solutions were taken
in separate 25 ml volumetric flasks and colour was developed in the same manner as
described above for the test samples. Colour intensity of these standard phosphorous
22
solutions was measured at 470 nm wavelength on a Spectrophotometer and standard
curve was constructed.
The colour intensity of test samples was measured and phosphorous concentration
was estimated from the standard curve and expressed as per cent P according to the formula
given below:
ppm x total dilution
Phosphorous (%) =
10,000
3.5.3.5 Potassium determination
Potassium was determined by the Flame Photometer method (AOAC 1990)
3.5.3.6 Potassium standard curve
From 1000 ppm potassium stock solution, 10 ml solution was taken in a 100 ml volumetric
flask and volume was made up to mark with distilled water to make 100 ppm stock solution.
Out of this 100 ppm stock solution 1, 2, 4, 6, 8 and 10 ml were taken in 100 ml volumetric
flask and volume was made up to mark with distilled water to get 1, 2, 4, 8 and 10 ppm
solution. For determining potassium in test samples, 1 ml of digested sample was taken in 25
ml volumetric flask and volume was made up to the mark with distilled water. The test
samples were fed to the atomizer of the flame photometer which had been adjusted with
standard K solution and readings were noted. The concentration of K present in the test
samples were found from the standard curve and expressed as per cent K according to the
formula as given below:
ppm x total dilution
Potassium (%) =
10,000
3.6 Statistical Analysis
The data recorded during the course of this study was analyzed statistically as
Randomized Block Design (factorial) as per procedure described by Singh et al (1998) and
the resulted are summarized in the table‟s average of three replications.
CHAPTER IV
RESULTS AND DISCUSSION
The present investigation, “Effect of foliar application of KNO3 on fruit yield and
quality attributes in litchi cultivar Dehradun‟ is presented in this chapter. The observations on
fruit and biochemical characters were recorded during the year 2015. The results are
presented in this chapter and discussed in light of available literature under suitable headings,
sub headings after tabulation and statistical analysis.
4.1 Fruit characters
4.1.1 Fruit weight
The data presented in Table 1 & Fig. 1 showed that number of sprays applied at
different KNO3 concentrations significantly affected fruit weight in litchi cv. Dehradun.
Higher mean fruit weight (21.5g) was recorded with the spray of KNO3 1% followed by
KNO3 1.5% (20.7 g) as compared to the control (20.0 g). With respect to number of sprays,
significantly maximum fruit weight (20.9 g) was recorded when trees were sprayed with one
spray of KNO3 as compared to two sprays (20.6 g) and minimum (20.0g) with three sprays.
The interaction between different treatments and number of sprays were significant and
improvement in fruit weight to the tune of 22.2 g was noted when trees were sprayed twice at
the interval of 10 and 20 days after fruit set (DAFS) with KNO3 1% concentration. Overall,
trees sprayed with potassium improved the fruit weight over the control except T2S3, T3S2 and
T3S3.
Table 1: Effect of foliar application of KNO3 in fruit weight (g) in litchi cv. Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 21.7 22.2 20.7 21.5
T2 (KNO3 – 1.5%) 21.4 21.1 19.7 20.7
T3 (KNO3 – 2.0%) 20.7 19.0 19.8 19.8
T4 (Control) 19.9 20.0 20.0 20.0
Mean 20.9 20.6 20.1
CD (p=0.05)
Treatment : 0.22
Spray : 0.19
Treatment x Spray : 0.38
24
Fig. 1 : Effect of foliar application of KNO3 on the fruit weight of litchi cv. Dehradun
Potassium is an important nutrient for fruit filling (size and weight) and improvement
in fruit quality and it is required for the production and transport of plant sugars which in turn
intend to increase the fruit weight (Menzel 1983). These results are in conformity with the
findings of Pathak and Mitra (2010) who noted an improvement in fruit weight with higher
leaf K content in litchi cultivar. The results also find support from the work done by Gill et al
(2012) in „Patharnakh‟ pear suggested that fruit weight was improved by foliar sprays of K
nutrient. Likely, two pre-harvest foliar sprays of Poly feed (19:19:19) on litchi plants at the
interval of 15 and 45 days after fruit set effectively increased fruit weight (Singh et al 2007).
4.1.2 Fruit retention (%)
The data in Table 2 revealed that fruit retention (%) in litchi (fruits/panicle) was
affected with various KNO3 treatments applied as one spray, two sprays and three sprays as
compared to the control (T4). In litchi cv. Dehradun significantly highest fruit retention
percentage (10.42%) was observed in T1 (10.42 %) and the lowest (9.27%) in T3. The effect
of number of sprays on fruit retention per cent was also evident and significant better was
observed with one spray (10.05); however, effect of two sprays (9.94) and three sprays (9.17)
of KNO3 was the lowest. The interactions effect among various treatments and number of
sprays were also statistically significant and maximum fruit retention (%) was observed in
trees treated with KNO3 1% when sprayed at an interval of 10 and 20 DAFS and minimum in
three sprays of KNO3 2%. The results are in conformity with the available literature that foliar
application of KNO3, K2SO4, KH2PO4 and KCl (1%) in „Banarasi‟ and „Karaka‟ ber cultivars
improved fruit retention (Yadav et al 2014).
17
18
19
20
21
22
23
KNO3 -1% KNO3 -1.5% KNO3 -2% Control
Fru
it w
eig
ht
(g)
Treatment
one spray two sprays three sprays
25
Table 2: Effect of foliar application of KNO3 on fruit retention in litchi cv. Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1KNO3-1% 10.39 10.62 10.25 10.42
T2KNO3-1.5% 10.16 9.81 8.58 9.52
T3KNO3-2% 10.00 9.64 8.17 9.27
T4Control 9.63 9.70 9.69 9.67
Mean 10.05 9.94 9.17
CD(p=0.05)
Treatment : 0.35
Spray : 0.22
Treatment x Spray : 1.01
4.1.3 Fruit length and diameter
The effect of different concentrations and number of sprays of potassium applied
in the form of KNO3 considerably improved fruit size as compared to the control (Table 3
& 4). Maximum fruit length (37.4 mm) was achieved with the spray of KNO3 1% (T1)
followed by KNO3 1.5% (T2) (36.9 mm) and minimum (36.1mm) in the control (T4);
however, treatments T1 and T2 were statistically at par with each other. The effect of
number of sprays was mentioned in Table 2 and 3 and higher length (37.0 mm) was
observed with one spray of KNO3 which was statistically significant higher than other
treatments i.e. two sprays (36.8 mm) and three sprays (36.1 mm). The effect of number of
sprays at different doses of KNO3 concentrations on fruit length was significantly the
highest (38.3mm) when KNO3 was applied twice at the interval of 10 and 20 days after
fruit set (DAFS) as compared to other treatments and the control. Meanwhile, higher
average breadth (34.2 mm) of „Dehradun‟ litchi fruits was recorded in T1 (KNO3 1%)
followed by 33.8 mm in T2 (KNO3 1.5%) and minimum 30.1 mm in the control (T4).
Number of KNO3 sprays in litchi cv. Dehradun also improved the fruit breadth and values
were 33.0 mm, 32.6 mm and 32.1 mm with one, two and three sprays, respectively.
However, the interaction effect between number of sprays and different KNO3
concentrations on fruit breadth was statistically non significant.
Bhargava et al (1993) reported that K nutrient is known to effect fruit quality by
influencing size. Similarly, Dutta and Banik (2007) also observed that fruit size was
increased with potassium application in „Sardar‟ guava. Increase in fruit size with the
application of K is due to increase in entry of water into the cells by osmotic processes
which subsequently increase cell size (Ruiz 2006). Potassium also affects the process of
phosphorylation, transportation of photo assimilates from source tissues via the phloem to
sink tissues, enzyme activation, turgor maintenance, transpiration, photosynthesis, stress
26
tolerance (Usherwood 1985, Pettigrew 2008). An increase in fruit length and diameter
was noted with the application of K on „Red Delicious‟ apples (Rashid et al 2008).
Mukadam and Haldankar (2013) revealed that foliar application of KNO3 (3%) at 20 days
after fruit set statistically improved fruit length and diameter in Karonda. Khayyat et al
(2012) postulated that pomegranate tree sprayed with KNO3 (250 mg l-1
) had shown the
mark able effect on fruit length and diameter as compared to the control.
Table 3: Effect of foliar application of KNO3 on fruit length (mm) in litchi cv.
Dehradun
Treatment Fruit Length (mm)
One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 38.1 38.3 35.9 37.4
T2 (KNO3 – 1.5%) 37.4 37.3 36.1 36.9
T3 (KNO3 – 2.0%) 36.5 35.6 36.3 36.2
T4 (Control) 36.1 36.1 36.0 36.1
Mean 37.0 36.8 36.1
CD (p=0.05)
Treatment : 0.47
Spray : 0.41
Treatment × Spray : 0.82
Table 4: Effect of foliar application of KNO3 on fruit diameter (mm) in litchi cv.
Dehradun
Treatment Fruit Diameter (mm)
One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 34.5 34.6 33.4 34.2
T2 (KNO3 – 1.5%) 34.4 33.5 33.4 33.8
T3 (KNO3 – 2.0%) 32.8 32.3 31.4 32.2
T4 (Control) 30.1 30.1 30.0 30.1
Mean 33.0 32.6 32.1
CD (p=0.05)
Treatment : 0.45
Spray : 0.39
Treatment × Spray : NS
4.1.4 Aril weight
The perusal of data presented in Table 5 & Fig. 2 with respect to spray of different
KNO3 concentrations on aril weight reveal that foliar feeding of KNO3 1% (T1) significantly
increased aril weight (15.6 g) followed by (14.2 g) in T2 (KNO3 1.5%) and minimum (13.8 g)
27
in the control; however, treatments T3 and T4 were statistically non significant with each
other. Number of sprays also affected aril weight and the highest (14.8 g) was recorded with
one spray of KNO3 followed by two sprays (14.3 g) and the lowest (13.6 g) in the trees
sprayed thrice. The effect of interactions on aril weight was significant and higher was
recorded when „Dehradun‟ litchi trees were sprayed with KNO3 1% as single and double
spray as compared to other treatments however; T1S1 and T1S2 treatments were statistically at
par with each other.
Table 5: Effect of foliar application of KNO3 on aril weight (g) in litchi cv. Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 16.1 16.0 14.6 15.6
T2 (KNO3 – 1.5%) 14.9 14.7 13.0 14.2
T3 (KNO3 – 2.0%) 14.5 12.8 13.1 13.5
T4 (Control) 13.8 13.8 13.8 13.8
Mean 14.8 14.3 13.6
CD(p=0.05)
Treatment : 0.50
Spray : 0.38
Treatment x spray : 1.17
Fig. 2: Effect of foliar application of KNO3 on aril weight (g) in litchi cv. Dehradun
11
12
13
14
15
16
17
KNO3 -1% KNO3 -1.5% KNO3 -2% Control
Ari
l w
eigh
t (g
)
Treatment
one spray two sprays three sprays
28
These results are in accordance to earlier findings of Pathak and Mitra (2010) who
stated that maximum fruit pulp per cent recovery was noted with medium rates of potassium
(600 g K2O) applied in two splits at 15 days after fruit set and 30 days before flowering. Two
pre-harvest foliar sprays of Polyfeed (19:19:19) on litchi plants at the interval of 15 and 45
days after fruit set effectively improved aril weight (Singh et al 2007). An increase in fruit
weight was noted with the application of K on „Red Delicious‟ apples (Rashid et al 2008).
4.1.5 Stone weight
The effect of foliar application of KNO3 on fruit stone weight (g) in Dehradun litchi
is presented in Table 6 and results reveal that KNO3 treatments did not affect fruit stone
weight significantly. However, the stone weight was affected significantly with number of
sprays and the highest (3.72 g) was recorded with three sprays. Among the interaction,
maximum mean fruit stone weight (3.65 g) was recorded in T2 (KNO3 1.5%). However, single
spray of KNO3 had the highest stone weight (3.72 g) and minimum with two sprays (3.67 g).
Table 6: Effect of foliar application of KNO3 on fruit stone weight (g) in litchi cv.
Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 3.40 3.65 3.50 3.52
T2 (KNO3 – 1.5%) 3.70 3.45 3.85 3.67
T3 (KNO3 – 2.0%) 3.50 3.40 3.80 3.57
T4 (Control) 3.70 3.75 3.71 3.72
Mean 3.58 3.56 3.72
CD(p=0.05)
Treatment : NS
Spray : 0.11
Treatment x spray : NS
4.1.6 Pericarp weight (g)
The perusal of data mentioned in Table 7 reveal that significantly higher pericarp
weight (2.9 g) was recorded in T2 followed by 2.8 g in T3 and minimum (2.5 g) in T1 and the
control; however, number sprays did not affect pericarp weight significantly. The interaction
between concentration and number of sprays were statistically significant and the highest (3.0
g) was observed in T2S2 over the control (2.5 g). Similar results were also observed by Pathak
and Mitra (2010) when the plants were applied with 400 g K2O in two splits at 15 days after
fruit set.
29
Table 7: Effect of foliar application of KNO3 on fruit pericarp weight (g) in litchi cv.
Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 2.3 2.5 2.6 2.5
T2 (KNO3 – 1.5%) 2.9 3.0 2.9 2.9
T3 (KNO3 – 2.0%) 2.7 2.8 2.9 2.8
T4 (Control) 2.5 2.6 2.5 2.5
Mean 2.6 2.7 2.7
CD(p=0.05)
Treatment : 0.10
Spray : NS
Treatment x spray : 0.31
4.1.7 Pulp/ stone ratio
The perusal of data presented in Table 8 & Fig. 3 depict that the effect of foliar
application of KNO3 on litchi pulp/ stone ratio was significantly higher (4.43) in T1 than T2
(3.88) and (3.78) in T3. The effect of the number of sprays on pulp/stone ratio was recorded
maximum with one spray (4.18) and minimum (3.68) with three sprays. Among the
interactions, maximum pulp/stone ratio of 4.72 was noted with KNO3 1% as single spray
which was significant higher than other treatments.
Table 8: Effect of foliar application of KNO3 on Pulp/stone ratio in litchi cv. Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 4.72 4.38 4.17 4.43
T2 (KNO3 – 1.5%) 4.01 4.25 3.38 3.88
T3 (KNO3 – 2.0%) 4.14 3.76 3.45 3.78
T4 (Control) 3.86 3.82 3.70 3.80
Mean 4.18 4.05 3.68
CD(p=0.05)
Treatment : 0.15
Spray : 0.13
Treatment x spray : 0.27
The improvement in pulp/stone ratio with the sprays of different concentrations of
KNO3 is due to increase in pulp weight which in turn considerably increased pulp/stone ratio
as also observed by Kumar and Kumar (2004) and they reported that Multi K (13:0:46)
significantly improved aril weight in litchi cv. Rose Scented under Pantnagar conditions of
Uttaranchal. In „Bombai‟ litchi cultivar under West Bengal conditions, Mitra et al (2002)
also opined that single spray of 4% KNO3 at 15 days after anthesis significantly improved
30
fruit aril percentage to the tune of 77.9 in comparison to single spray of KNO3 4% after 21 or
28 days, and three sprays at 15, 21 and 28 days after anthesis.
Fig. 3: Effect of foliar application of KNO3 on pulp/stone ratio in litchi cv. Dehradun
4.1.8 Fruit Volume
Maximum (21.3 ml) fruit volume was recorded when trees were sprayed with 1%
KNO3 which was statistically at par with T2 (20.1 cc) followed T3 (19.5 cc) and (18.7 cc) in
T4 (Table 9). The effect of number of sprays on fruit volume was significantly higher (21.5
cc) in T1S2 followed by T1S1 (21.3 cc), T1S3 and T2S1 (21.0 cc) T2S2 (20.5 cc), T3S1 (20.2 cc)
than the other treatments where values were ranged between 18.6 to 19.3 cc.
Table 9: Effect of foliar application of KNO3 on fruit volume (cc) in litchi cv. Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 21.3 21.5 21.0 21.3
T2 (KNO3 – 1.5%) 21.0 20.5 18.8 20.1
T3 (KNO3 – 2.0%) 20.2 19.0 19.3 19.5
T4 (Control) 18.6 18.8 18.6 18.7
Mean 20.3 20.0 19.4
CD (p=0.05)
Treatment : 0.88
Spray : 0.37
Treatment x spray : 1.67
2.5
3
3.5
4
4.5
5
KNO3 -1% KNO3 -1.5% KNO3 -2% Control
Pu
lp/s
ton
e ra
tio
Treatment
one spray two sprays three sprays
31
4.1.9 Specific gravity
Foliar application of potassium nitrate also influenced fruit specific gravity as cleared
from Table 10. Trees treated with KNO3 recorded specific gravity between 1.01 to 1.03 and the
highest (1.07) in the control. It was observed that maturity process was delayed in trees treated
with K while it was increased with KNO3 @ 1.5% and again a decrease was observed in 2%
KNO3 treatment. The effect of number of sprays and their interactions on fruit specific gravity
with KNO3 were statistically non significant. These findings are in accordance with the findings
of Johnston (1999) that potassium delays ripening process but promotes more even ripening.
Similar results were also observed by Singh et al (2013) who reported that regular increase in
specific gravity denotes rapid increase in fruit weight as compared to fruit volume while
conducting studies on fruit development and maturation in litchi cultivar „Rose Scented‟.
Table 10: Effect of foliar application of KNO3 on specific gravity in litchi cv. Dehradun
Treatment One Spray (S1) Two Sprays (S2) Three Sprays (S3) Mean
T1 (KNO3 – 1.0%) 1.02 1.03 0.99 1.01
T2 (KNO3 – 1.5%) 1.02 1.03 1.05 1.03
T3 (KNO3 – 2.0%) 1.02 1.00 1.03 1.02
T4 (Control) 1.07 1.07 1.08 1.07
Mean 1.03 1.03 1.04
CD (p=0.05)
Treatment : 0.02
Spray : NS
Treatment x spray : NS
4.1.10 Fruit colour
The effect of foliar application of KNO3 on fruit pericarp colour in litchi cv. Dehradun
is presented in Table 11. The highest mean value of ‘L’ (35.2) was recorded in trees treated
with KNO3 1.5% (T2) followed by 34.8 in KNO3 1%, while, the lowest (31.8) in the treatment
T3. The effect of numbers of sprays on development of saturation lightness ‘L’ in fruit colour
was also significant and single spray of KNO3 had shown pronounce effect in producing higher
‘L’ value (34.6) followed by three sprays (33.3) and least with two sprays (32.9) (Fig. 3).
Among the interaction, the effect was observed significantly higher with one spray of 1.5 %
than other treatments and the control. Red pericarp colour development in litchi fruit is
indicated by ‘a’ coordinate and it was increased with the different doses of KNO3 applied at
different time intervals. The plants treated with KNO3 2% (T3) recorded significantly higher
‘a’ value (18.6) followed by (17.9) in KNO3 1% (T1) and (18.0) in KNO3 @ 1.5% (T2), while
lowest (17.5) was observed in the control as cleared from Fig. 4. Among the number of sprays,
one spray gave significantly highest mean ‘a’ value (19.5), followed by two sprays (17.7) and
least with three sprays (16.9). Among the interaction, maximum „a’ (20.5) coordinate was
noted with combinations of single spray of KNO3 1.5% and minimum (16.2) in T1S3 i.e. three
sprays of KNO3 1%.
32
Table 11: Effect of foliar application of KNO3 on fruit colour in litchi cv. Dehradun
Treatment
Coordinates
„L‟ value „a‟ value „b‟ value
One
Spray
(S1)
Two
Sprays
(S2)
Three
Sprays
(S3)
Mean One
Spray
(S1)
Two
Sprays
(S2)
Three
Sprays
(S3)
Mean One
Spray
(S1)
Two
Sprays (S2)
Three
Sprays
(S3)
Mean
T1 (KNO3 -
1.0%)
35.4 33.8 35.2 34.8 19.8 17.7 16.2 17.9 17.1 17.3 17.7 17.4
T2 (KNO3 -
1.5%)
37.5 34.9 33.2 35.2 20.5 18.1 15.3 18.0 17.3 17.0 16.0 16.8
T3 (KNO3 -
2.0%)
32.7 30.4 32.4 31.8 20.3 17.2 18.4 18.6 16.8 13.9 13.8 14.8
T4 (Control) 32.6 32.6 32.6 32.6 17.5 17.5 17.5 17.5 14.8 14.8 14.8 14.8
Mean 34.6 32.9 33.3 19.5 17.7 16.9 16.5 15.8 15.6
CD (p=0.05)
Treatment : 1.43
Spray : 1.51
Treatment x spray : 2.86
CD (p=0.05)
Treatment : 2.55
Spray : 2.64
Treatment x spray : 6.11
CD (p=0.05)
Treatment : 0.52
Spray : 0.21
Treatment x spray : 1.11
33
The ‘b’ value indicates the yellowness colour of the fruit and the application of potassium
nitrate had significantly affected on pericarp colour (Table 10). Maximum ‘b’ value (17.4) was
recorded with KNO3 1% followed by KNO3 1.5% (16.8) and minimum (14.8) was recorded both
in T3 (KNO3 2%) and the control as cleared from Fig. 5. The effect of number of sprays of KNO3
on colour development was maximum with single spray (16.5) followed by two sprays (15.8) and
minimum in three sprays. The effect of interactions was significantly higher in three sprays of
KNO3 1% (T1S3), followed by T1S2 and T2S1 (17.3), T1S1 (17.1), T2S2 (17.0), T3S1 (16.8) as
compared rest of the treatments including the control; however, lower value to the tune of 13.8
was noted in T3S3.
The above findings are in confirmation with the literature as suggested by Fisher
and Kwong (1961) that improvement in colour was noted with application of K
fertilization might be due to increased in carbohydrates accumulation in the fruits. In
peaches, Trevisan et al (2006) opined that soil application (1200 g of KCl + 10 g KCl) as
foliar application combined with vegetative pruning improved red coloration of fruits.
Similarly, Yang et al (2008) reported that potassium fertilization improved fruit
appearance, pigmentation index and ‛L’, ‛a’ and ‛b’ colour coordinates of fruit tip and
fruit body in ‛Yanguang‟ nectarines.
Fig. 4: Effect of foliar application of KNO3 on „L’ colour coordinate of litchi cv.
Dehradun
25
28
31
34
37
40
KNO3 -1% KNO3 -1.5% KNO3 -2% Control
'L'
valu
e
Treatment
one spray two sprays three sprays
34
Fig. 4: Effect of foliar application of KNO3 on „a’ colour coordinate of litchi cv.
Dehradun
Fig. 5: Effect of foliar application of KNO3 on „b’ colour coordinate of litchi cv.
Dehradun
12
14
16
18
20
22
KNO3 -1% KNO3 -1.5% KNO3 -2% Control
'a'
va
lue
Treatment
one spray two sprays three sprays
12
14
16
18
20
KNO3 -1% KNO3 -1.5% KNO3 -2% Control
'b'
va
lue
Treatment
one spray two sprays three sprays
35
4.2 Fruit Chemical Characteristics
4.2.1 Soluble Solids Content (SSC)
The improvement in fruit juice soluble solids content (SSC) was noted with foliar
feeding of KNO3 (Table 12). Increased in SSC 20.97%) was noted with KNO3 1.5% and it
was statistically at par with (20.83%) in KNO3 2% and the least (18.80%) in the control.
Number of sprays also affected soluble solid content of fruits. Highest fruit SSC (20.45%)
was recorded with three sprays followed by (20.18%) two sprays and the lowest with single
spray. Among the interactions, the combination effect of concentrations and timing intervals
was noted maximum in T3S1 and the minimum in the control. The application of KNO3
applied at different intervals significantly improved the SSC over the control except T1S1 T3S2
and values ranged from 20.8 to 21.3o Brix.
Table 12: Effect of foliar application of KNO3 on soluble solid content (%) in litchi cv.
Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 19.30 21.05 20.90 20.42
T2 (KNO3 – 1.5%) 21.15 20.80 20.95 20.97
T3 (KNO3 – 2.0%) 21.25 20.10 21.15 20.83
T4 (Control) 18.80 18.77 18.80 18.79
Mean 20.13 20.18 20.45
CD(p=0.05)
Treatment : 0.49
Spray : 0.42
Treatment x spray : 0.84
These results are corroborated with the findings of Dilmaghani et al (2005) who
stated that application of K at high rates significantly increased fruit soluble solids content in
„Golden Delicious‟ apples and maximum TSS was recorded with application of 1000g K2O
per tree in „Starking Delicious‟ apples (Kainth and Awasthi 2010). In „Sardar‟ guava, Dutta
(2004) reported that treatments viz. KNO3, K2SO4 and KCl noticeably increased fruit juice
total soluble solids.
4.2.2 Titratable acidity
The different K treatments as foliar feeding significantly influenced fruit juice
titratable acid content (TA) and the results are presented in Table 13. The highest 0.58% TA
was obtained in T3 (KNO3 2%), followed by T1 (0.55%) and minimum in T2 (0.50%)
Among comparison between number of sprays, minimum (0.52%) TA was recorded with
three sprays and the maximum (0.55%) with one spray of KNO3. Among the interactions,
maximum (0.61%) titratable acid content was recorded with two sprays of 2% KNO3 and
36
minimum with single spray of 1% KNO3. The above findings are confirmatory with the
results of Hunsche et al (2003) that increase in the dose of potassium as soil application
significantly increased juice acidity in „Fuji‟ apples. The relationship between the leaf
nutrients and fruit quality attributes showed positive relationships between leaf potassium
(K) and titratable acidity as also observed by Sivakumar and Korsten (2007). The lowest
(0.31%) fruit acidity was noted with the application of 600 g K2O in two splits at 15 days
after fruit set and 30 days before flowering in litchi cultivar „Bombai‟as reported by Pathak
and Mitra (2010).
Table 13: Effect of foliar application of KNO3 on juice titratable acidity (%) in litchi
cv. Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 0.51 0.56 0.57 0.55
T2 (KNO3 – 1.5%) 0.60 0.45 0.46 0.50
T3 (KNO3 – 2.0%) 0.58 0.61 0.56 0.58
T4 (Control) 0.49 0.50 0.48 0.49
Mean 0.55 0.53 0.52
CD(p=0.05)
Treatment : 0.13
Spray : 0.012
Treatment x spray : 0.14
4.2.3 TSS/acid ratio
The data presented in Table 14 reveal that different foliar K treatments and number of
sprays significantly influenced TSS/acid ratio in litchi cv. Dehradun. The highest TSS/acid
ratio (44.2) was recorded in T2 (KNO3 1.5%) which was significantly higher than all the other
treatments. The lowest value of 35.2 was registered in the control. Number of sprays had
positive influence on TSS/acid ratio and three sprays of KNO3 had proved the best with
highest TSS/acid ratio of 39.07 and the lowest of 37.7 with single spray. With respect to the
interaction, maximum TSS/acid ratio was recorded in T2S2 followed by T2S3 (45.8), T3S1 (42.1)
and minimum (34.5) in the control.
Similar findings were also reported by Pathak and Mitra (2010) that lowest (0.31 %)
fruit acid content and the highest Brix/acid ratio 64.01 were noted with soil application of 600
g K2O in two splits at 15 days after fruit set and 30 days before flowering in litchi cultivar
„Bombai‟. In apple cv. „Red Delicious‟, soil application of K notably increased total soluble
solids (TSS), however, fruit acid content was decreased drastically (Rashid et al 2008).
Chanana and Gill (2008) reported that foliar application of K2SO4 substantially improved total
37
soluble solids and decreased the fruit acidity in „Perlette‟grapes. Pathak et al (2013) also
stated that higher rates of both P and K markedly reduced the fruit acidity, however, increased
TSS/acid ratio and a decrease of fruit acidity were more pronounced with the addition of B
and S along with P and K.
Table 14: Effect of foliar application of KNO3 on SSC/TA ratio in litchi cv. Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 33.54 36.24 37.01 35.60
T2 (KNO3 – 1.5%) 40.55 46.25 45.81 44.20
T3 (KNO3 – 2.0%) 42.11 35.78 37.25 38.38
T4 (Control) 34.76 34.50 36.21 35.16
Mean 37.74 38.19 39.07
CD(p=0.05)
Treatment : 0.95
Spray : 0.80
Treatment x spray : 1.64
4.2.4 Total sugars (%)
The different KNO3 treatments significantly influenced litchi juice total sugars
content (Table 15). Among different treatments, maximum total sugars (14.85%) was
recorded in T3 followed by T2 (14.37%) and minimum 14.07% in T1. Among the comparison
between numbers of spray, three sprays prominently improved total sugars to the tune of
14.79% and minimum (13.84%) was observed from trees treated with one spray. Amongst the
interactions, the effect was significantly higher (15.84%) with three spray of KNO3 2% and
minimum (13.54%) with single application of 1% KNO3.
The results are in accordance with the findings of Ahlawat and Yamdagini (1981)
who reported that increased total sugars with potassium in guava fruits might be attributed to
higher assimilating power of leaves over longer period resulting in increased availability of
sugars to fruits. Potassium is known to enhance photophosphorylation and dark reaction of
photosynthesis resulting in increased accumulation of carbohydrates. According to Taiz and
Zeiger (2004), the efflux of sucrose to the apoplast is facilitated by potassium availability,
which thereby increases sugar translocation from source to sink tissues, promoting their
growth. The results are in harmony with the findings of Pathak and Mitra (2010) who have
reported that fruits from the plants receiving 800 g potassium in two splits at 15 days after
fruit set and 30 days before flowering showed the maximum total sugars (16.11%) content of
fruits in litchi „Bombai‟ cultivar. In „Rose Scented‟ litchi under Uttranchal conditions, Kumar
and Kumar (2004) confirmed that three pre harvest foliar sprays of „Multi-K‟ (1.0 %) @ 15,
38
30 and 45 days after fruit set considerably produced fruits with higher total sugars. Two pre-
harvest foliar sprays of Polyfeed (19:19:19) on litchi plants at the interval of 15 and 45 days
after fruit set effectively produced fruits with maximum total sugars, reducing sugars (Singh
et al 2007).
Table 15: Effect of foliar application of KNO3 on total sugars (%) in litchi cv. Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 13.5 14.3 14.6 14.1
T2 (KNO3 – 1.5%) 14.1 14.8 15.4 14.8
T3 (KNO3 – 2.0%) 15.6 13.7 14.5 14.6
T4 (Control) 13.0 13.1 13.1 13.1
Mean 14.1 14.0 14.4
CD(p=0.05)
Treatment :0.30
Spray :0.26
Treatment x spray :0.52
4.2.5 Reducing sugars
The data pertaining to effect of K nutrients on fruit juice reducing sugars is
presented in Table 16. The effect of foliar application of KNO3 had a positive effect on the
reducing sugars. The highest (10.63%) significant reducing sugar was obtained from the
treatment T3 i.e. KNO3 2%. followed by T2 (9.73%) and minimum in the control. The
number of sprays also affected the reducing sugar content in the fruits of litchi. Maximum
mean value (9.54%) was obtained from three sprays while minimum (9.16%) was from
trees sprayed once. The interaction effect was also evident with the combination of KNO3
@ 2% when sprayed thrice (10.97%) produced the maximum and minimum in the control
(7.35%). Pathak and Mitra (2010) reported the similar results stating that fruits from the
plants receiving 800 g Potassium (higher dose of potassium) in two splits at 15 days after
fruit set and 30 days before flowering showed the maximum reducing sugar (14.65%)
content of fruit. Various other researchers reported similar findings of increase in reducing
sugar content with potassium application, Kumar et al (2006) in „Alphonso‟ mango, Hudina
and Stamper (2002) in pear cv. Williams. Two pre-harvest foliar sprays of Polyfeed
(19:19:19) on litchi plants at the interval of 15 and 45 days after fruit set effectively
produced fruits with maximum reducing sugars content (Singh et al 2007).
39
Table 16: Effect of foliar application of KNO3 on reducing sugars (%) in litchi cv.
Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 9.3 9.3 9.5 9.4
T2 (KNO3 – 1.5%) 9.5 9.7 10.0 9.7
T3 (KNO3 – 2.0%) 10.3 10.6 11.0 10.6
T4 (Control) 7.5 7.4 7.7 7.5
Mean 9.2 9.2 9.5
CD(p=0.05)
Treatment : 0.17
Spray : 0.14
Treatment x spray : 0.29
4.2.6 Non reducing sugars (%)
Data representing non reducing sugars content is given in the Table 17. The highest
non reducing sugar (4.71%) was obtained from T1 and minimum in T3. The effect of the
frequency of sprays was also evident as maximum values for non reducing sugars were
obtained with three sprays and minimum with one spray. Among interactions, non reducing
sugars of fruits from trees sprayed with KNO3 had the highest non reducing sugars and best
was observed with KNO3 1% with two sprays.
Table 17: Effect of foliar application of KNO3 on non reducing sugar (%) in litchi cv.
Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 4.2 5.0 5.1 4.8
T2 (KNO3 – 1.5%) 4.6 5.1 5.4 5.
T3 (KNO3 – 2.0%) 5.3 3.1 3.5 3.9
T4 (Control) 5.5 5.8 5.4 5.6
Mean 4.9 4.7 4.9
CD(p=0.05)
Treatment : 0.39
Spray : 0.34
Treatment x spray : 0.67
40
4.2.7 Fruit yield (Kg/ tree)
It is pertinent to mention that foliar application of potassium nitrate influenced the
fruit yield in litchi cv. Dehradun as compared to the control (Table 18). The highest fruit yield
(89.8 Kg tree-1
) was obtained in trees sprayed with KNO3 1% followed by (82.9 Kg tree-1
) in
KNO3 1.5% and minimum (75.2 Kg tree-1
) in trees sprayed with KNO3 2%. It is further
observed that significant decreased in fruit yield was noted with higher dose of KNO3 as
recorded in T2 and T3 in comparison to T1. However, number of sprays also confirmed distinct
effect on litchi fruit yield being maximum (85.0 Kg tree-1
) in single spray followed by double
spray (81.8 Kg tree-1
) and minimum with three sprays (77.1 Kg tree-1
). Among the
interactions between doses of KNO3 and number of sprays, significantly maximum effect was
noted T1S2 (94.8 Kg tree-1
) followed by T2S1 (90.1 Kg tree-1
) over the other treatments
including control. The improvement in fruit yield was due to increase in yield related
components like fruit weight, fruit size and fruit retention as evident from Table 1, 2, 3 and 4.
Table 18: Effect of foliar application of KNO3 on fruit yield (Kg/tree) in litchi cv.
Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 89.7 94.8 84.9 89.8
T2 (KNO3 – 1.5%) 90.1 82.2 76.4 82.9
T3 (KNO3 – 2.0%) 82.9 73.1 69.7 75.2
T4 (Control) 77.5 77.1 77.3 77.3
Mean 85.1 81.8 77.0
CD(p=0.05)
Treatment : 3.82
Spray : 1.77
Treatment x spray : 7.08
The present findings also correlated with previous findings that twice application of
KNO3 at the concentrations of 2.0 to 4.0 percent substantially increased fruit yield of „Valencia‟
oranges as reported by Bakr et al (1980). In Pomegranate cv. Ganesh, maximum fruit set and yield
was recorded with N and K (500 g/plant) (Kashyap et al, 2012). Similarly, Koo and Reece (1972)
reported that improvement in fruit yield with the application of KNO3 is related to production of
bigger fruit size and higher number of fruits. Yang et al (2015) reported that fruit yield and cost
benefit ratio in litchi cv. „Feizixiao‟ initially increased and then subsequently decreased with the
increasing K2O/N ratio. The application of K (600 g plant-1 year
-1) in two equal splits i.e. after 15
days after fruit set and 15 days after harvest considerably increased fruit yield (91.84 kg plant-1
year-1) as reported by Pathak and Mitra (2010).
41
4.3 Leaf nutrient composition
4.3.1 Leaf Nitrogen (N)
The data on leaf N content as influenced with different concentrations of KNO3 is
presented in Table 19; however, the effect of potassium nitrate on leaf N content was
statistically significant. The results had shown that maximum (1.80) leaf N content was
observed in trees treated with KNO3 2% (T3) however, treatments viz., T1 (1.53), T2 (1.63)
andT4 (1.64) were statistically at par with each other. These values are within critical optimum
limits of 1.5 to 1.8 % for leaf nutrient concentrations as suggested by Menzel et al (1992).
Leaf N content, where trees were sprayed one, two or three times as well as the interactions
between doses and number of sprays were statistically significant with each other. Sarrwy
(2012) stated that foliar application of various forms of potassium on “Balady” Mandarin
trees significantly raised the nitrogen content in leaves.
Table 19: Effect of foliar spray of KNO3 on nitrogen content (%) in leaves of litchi cv.
Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 1.54 1.58 1.62 1.58
T2 (KNO3 – 1.5%) 1.63 1.66 1.69 1.66
T3 (KNO3 – 2.0%) 1.63 1.88 1.91 1.81
T4 (Control) 1.48 1.47 1.48 1.48
Mean 1.57 1.65 1.68
CD(p=0.05)
Treatment : 0.08
Spray : NS
Treatment x spray : 0.17
4.3.2 Leaf Phosphorus (P)
The data presented in Table 20 revealed that various K treatments and number of
sprays did not influence the leaf P content significantly. However, maximum leaf P content to
the tune of 0.301% was obtained with KNO3 1% (T1). These results are in accordance with
earlier findings of Bakr et al (1980) who reported that K fertilization had no appreciable
effect on the leaf P content of „Valencia‟ orange and Attala et al (2007) in apple cv. „Golden
Delicious‟.
42
Table 20: Effect of foliar spray of KNO3 on phosphorus(%) content in leaves of litchi
cv. Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three
Sprays (S3)
Mean
T1 (KNO3 – 1.0%) 0.230 0.231 0.228 0.301
T2 (KNO3 – 1.5%) 0.232 0.235 0.239 0.235
T3 (KNO3 – 2.0%) 0.226 0.228 0.230 0.228
T4 (Control) 0.224 0.225 0.229 0.226
Mean 0.228 0.230 0.232
CD(p=0.05)
Treatment : NS
Spray : NS
Treatment x spray : NS
4.3.3 Potassium (K)
The trees applied with KNO3 at different doses as single, double and thrice as foliar
sprays in litchi cv. Dehradun had significantly influenced leaf K content (Table 21). In
treatment i.e. 2% KNO3 significantly the highest (1.02%) leaf K content was recorded in T3 as
compared to minimum (0.53) in the control (T4). The results validate the earlier findings that
application of higher level of potassium increase the potassium content in leaf in litchi cv.
Bombai (Pathak et al 2013).
Table 21: Effect of foliar spray of KNO3 on potassium content (%) in leaves of litchi
cv. Dehradun
Treatment One Spray
(S1)
Two Sprays
(S2)
Three Sprays
(S3)
Mean
T1 (KNO3 – 1.0%) 0.70 0.75 0.85 0.77
T2 (KNO3 – 1.5%) 0.71 0.79 1.15 0.88
T3 (KNO3 – 2.0%) 0.82 1.01 1.23 1.02
T4 (Control) 0.52 0.55 0.53 0.53
Mean 0.69 0.78 0.94
CD(p=0.05)
Treatment : 0.17
Spray : 0.11
Treatment x spray : 0.29
43
Fig. 6: Effect of foliar application of KNO3 on litchi leaf K content
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
KNO3 -1% KNO3 -1.5% KNO3 -2% Control
Po
tass
ium
co
nte
nt
(%)
Treatment
one spray two sprays three sprays
CHAPTER V
SUMMARY
Litchi (Litchi chinensis Sonn.) recognized as “Queen of the fruits” is an important sub
tropical evergreen fruit crop belongs to the family Sapindaceae. Litchi crop is widely
distributed in the tropics and warm subtropics of the world. It is a highly priced fruit and is
used in the form of fresh fruit and preparation of value added products i.e. RTS, squash, dry
nut etc. It performs best in the regions possessing cool dry frost-free winters and warm
summers with high rainfall and humid climatic conditions (Menzel 1983). Litchi fruits are
rich in sugar contents and it varies from 6.74-18.0%, juice acid content 0.20 to 0.64% in the
form of malic acid and also possesses citric acid, succinic acid, levulinic acid, phosphoric
acid, glutamic, malonic and lactic acids. It also contains 40.2-90 mg vitamin-C/100 g edible
portion, 0.9% protein, 0.3% fat, 0.424% pectin and 0.7% minerals (Ca, P, Fe). Litchi skin is
rich in insoluble fiber, which prevents rectum cancer, diabetes and heamorrhoids. Wang et al
(2010) reported that water soluble alcohol extracted from litchi skin significantly inhibited in
vitro growth of human hepatoma cells and suppressed cancer development particularly
effective in the suppression of breast cancer. However, tree metabolic functions should be
improved and ineffective rate of respiration also reduced by using an appropriate K fertilizer,
which is in turn essential for the improvement of the tree‟s carbohydrate supply, accumulation
level, fruit setting and yield.
It is therefore, the present investigation entitled „Effect of foliar application of KNO3
on fruit yield and quality in Litchi‟ was carried out at MS Randhawa Fruit Research Station,
Gangian (Dasuya), Hoshiarpur. Fruit and leaf analysis was done at PG and Leaf Analysis
Laboratory, Department of Fruit Science, Punjab Agricultural University, Ludhiana during
2015-16. During the studies, the different concentration of potassium nitrate (KNO3) along
with different frequencies of foliar spray was evaluated to assess their effect on various
morphological and biochemical characteristics of litchi cv. Dehradun. The fruits were
evaluated for the following morphological and biochemical traits, viz. fruit size (l x b) (cm),
fruit weight (g), fruit volume (cc), specific gravity, colour coordinates (l, a and b), pulp
weight (g), pericarp weight (g), stone weight (g), pulp/stone ratio, juice titratable acid content
(TA) (%), soluble solid contents (SSC) (%), SSC/TA ratio, anthocyanin content (mg/100g
fruit pericarp), sugar concentrations (%) i.e. total sugars (%), reducing sugars(%), non
reducing sugars(%), fruit retention, fruit yield (kg/tree), leaf macro and micro nutrient
contents. The salient findings are summarized below.
Maximum fruit weight and fruit size was noted in T1 where KNO3 1% was applied
twice at 10 and 20 DAFS and the lowest was in T3. Likewise, foliar feeding of KNO3 1% (T1)
significantly increased fruit pulp weight (15.6 g) followed by (14.2 g) in T2 (KNO3 1.5%) and
45
minimum T3 (13.5 g). The number of sprays also affected fruit pulp weight and maximum
(14.8 g) was recorded with one spray followed by two sprays (14.3 g) and the least (13.6 g)
with three sprays. The effect of different interactions on fruit pulp weight was statistically
significant. Fruit retention (%) was also significantly influenced by the foliar application of K
nutrient and the highest value was observed with two sprays of KNO3 1%. Maximum (4.43)
pulp/ stone ratio was obtained in T1 followed by (3.88) in T2. The effect of the number of
sprays was noted maximum with one spray (4.18) and minimum (3.68) with three sprays.
Among the interactions, maximum pulp/stone ratio (4.72) was noted with one spray of KNO3
@ 1% which was statistically significant over the control.
Maximum fruit length (37.4 mm) was achieved with the spray of KNO3 1% (T1)
followed by KNO3 1.5% (T2) (36.9 mm) and minimum (36.1 mm) in the control (T4).
Maximum mean length (37.0 mm) was observed with one spray of KNO3 which was
statistically significant than the results obtained from two sprays (36.8 mm) and three sprays
(36.1 mm). The effect of number of sprays and different KNO3concentrations on fruit length
was significantly maximum (38.3 mm) when KNO3 was applied twice at the interval of 10
and 20 DAFS as compared to other treatments and the control. The highest average breadth
(34.2 mm) of litchi fruits was recorded in treatment KNO3 1% (T1) followed by (33.8 mm)
with KNO3 1.5% (T2) and minimum (30.1 mm) in the control (T4). Number of KNO3 sprays
also improved the fruit breadth and values were 33.0, 32.6 and 32.1 mm with one, two and
three sprays, respectively. However, the interaction between number of sprays and different
KNO3 concentrations on fruit breadth was statistically non significant.
Trees treated with KNO3 recorded specific gravity between 1.01 to 1.03 and higher
(1.07) in the control. It was observed that maturity process was delayed in trees treated with
KNO3 %, while it was increased with KNO3 1.5% and again a decrease was observed in 2%
KNO3 treatment. However, the effect of number of sprays as well as interaction were
statistically non significant. The colour coordinates recorded and ‘L’ value was highest in T2
(single spray of KNO3 1.5%), ‘a’ value in T3 (KNO3 2%) and ‘b’ value with T1 (KNO3 1%).
Juice soluble solids content (SSC) was also significantly affected by the foliar
application of KNO3 and maximum was noted with T2 (three sprays of KNO3 1.5%). Juice
titratable acidity (%) was maximum in T3 (KNO3 2%). However, higher value of TSS/Acidity
ratio was noticed in plants sprayed with T2 (three sprays of KNO3 1.5%). Sugar content was
increased as the dose of KNO3 was increased from 1 to 1.5 per cent and subsequently
decreased at KNO3 2%. Maximum total sugars and reducing sugars content was observed
when KNO3 1.5% was sprayed thrice and minimum non reducing sugars content was noticed
in T3 (three sprays of KNO3 2%). Fruit yield was also improved and the highest yield was
observed with two sprays of KNO3 1% at 10 and 20 DAFS. Leaf N and K contents were
46
significantly improved with the foliar feeding of KNO3 when applied one, two and three
times at the interval of 10 days from fruit set as compared to the control trees (water spray).
However, the highest values were noted in plants treated with KNO3 2%. Leaf P content was
non significantly affected by different K treatments.
It is concluded that KNO3 @ 1.0 per cent applied after 10 DAFS (S1) significantly
improved fruit retention (%), fruit size, weight, aril weight, pericarp colour, pulp/ stone ratio,
TSS/acid ratio and total sugars. To authenticate the results, long term experiment should be
conducted however, litchi in the market fetches the highest price on the basis of fruit reddish
colour and fruit size. The growers are benefitted in term of improvement of fruit retention (%)
and fruit colour development due to foliar feeding of KNO3 at significant time intervals.
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VITA
Name : Divya Pandey
Father's Name : Shri Sudhir Pandey
Mother's Name : Smt.Asha Pandey
Nationality : Indian
Date of Birth : 9 December, 1990
Permanent Address : LDS-4, Sector-D, LDA Colony,
Kanpur Road, Lucknow-226012,
Uttar Pradesh
EDUCATIONAL QUALIFICATIONS
Bachelor's degree : B.Sc. Agriculture
University and year of award : Sam Higginbottom Institute of Agriculture,
Technology and Sciences, Allahabad (UP),
2014
OCPA : 9.60/10.00
Master's degree : M.Sc. Horticulture (Fruit Science)
University and year of Award : Punjab Agricultural University, Ludhiana
(Punjab), 2016
OCPA : 7.99/10.00
Title of Master's Thesis : Effect of foliar application of KNO3 on
fruit yield and quality in litchi
Awards, Fellowships/ Scholarships : ICAR Junior Research Fellowship (JRF)
during M.Sc. Programme
