International Journal of Horticultural Science 2016, 22 (3–4): 7–19.
Agroinform Publishing House, Budapest, Printed in Hungary
In Egypt, peach crop presents an important economic
value and exporting potential. According to (FAO, 2013) the
area cultivated with peach in Egypt is 59960.72 feddans in
which produced 281 814 tons/year. Peach gained its economic
importance from these early and mid-season low chilling
cultivars which introduced in last several years, mainly from
the U.S.A by the Agriculture Development system (Shaltout,
1995). From these cultivars, the Desert red cultivar which is
considered an early and low chilling one; it matures at third
week of May under Egyptian conditions. It exhibited a high
adaptation with the local environmental conditions.
Desert red peach tree cultivar suffers from some problems
such as ; a-low fruit quality because of producing a large
number of fruits that can set more than that is required to
get commercial yield and thereby there is a negative impact
on fruit size, and other fruit characteristics remain mediocre,
particularly the chemical characteristics of fruits such as
sugar concentration and acidity unless dormant pruning and
fruit thinning were done, and b-doubles and deep sutures
which recognized as physiological disorders related to water
stress either resulting from drought or decit irrigation
especially during bud differentiation after harvest in the
previous season (Kader 2002).These disorders render fruits
unmarketable, however double fruits can be separated by
hand thinning and sorting, deep sutures are intractable to
expose on small fruitlets (Handley and Johnson, 2000).
There are certain factors that may inuence of on
chemical and physical fruit quality and fruit growth like light
distribution in peach tree canopy and competition between
fruits. (Chartzoulakis et al., 1993). Using pruning for peach
tree is important for light penetration and modifying the
number of shoots bearing fruit within tree canopy which have
a great effect on fruit growth and quality (Marini and Sowers,
1994). So, it can obtain fruits with higher fruit quality by
increasing ux of light shined to the fruit (Shiukhy et al.,
2014). Also light penetration is important to the maintenance
of high quality fruit wood and development of ower buds
(Erez and Flore, 1986).
We can overcome the adverse effects of high crop load
(as small fruit size and poor quality, breakage of limbs,
exhaustion of tree reserves, and reduced cold hardiness)
by fruit thinning(Meitei et al., 2013). Fruit thinning is
fundamental, horticultural practices for improving quality
in terms of fruit size, increasing sugar concentration and
reduction acidity fruit colour, shape, maximizing crop value,
maintaining tree growth and structure (Byers et al., 2003)
and for removing double fruits(Handley and Johnson 2000).
Other advantages of this technique are well known viz.
Treatments for improving tree growth, yield and fruit
quality and for reducing double fruit and deep suture
incidence in “Desert red” peach trees
Zayan, M.A.1, Mikhael, G. B.2 & Okba, S.K.21
1Department of Horticulture, Faculty of Agriculture, University of Egypt, Kafr El-Sheikh, Egypt
2Horticultural Research Institute, ARC, Giza, Egypt
Summary: Five years old “Desert red” peach trees budded on Nemaguard rootstock and grown in sandy soil at commercial orchard Al-Nubaria
city, El-Behira Governorate-Egypt were treated with some agricultural treatments involving thinning out pruning, fruit thinning and foliar
application of potassium silicate (25% S +10% K2O) at 0.1% and super grow (20% N, 20% P2O5 and 20% K2O) at 0.3% in 2014 and 2015
seasons, to study their effects on yield and fruit quality and the relationship between nutrient balance and yield of “Desert red” peach trees.
Beside, testing the inuence of used treatments on two physiological disorder, double fruit and deep suture %. Also, economic evaluation
of different treatments was done. All obtained data were statistically analyzed using a randomized complete block design. Depending on the
obtained results in this study, it could be concluded that application of thinning out pruning 35%, fruit thinning by leaving 15 cm between
fruits on one-year old shoot at 20 days after full bloom and foliar application of potassium silicate which sprayed ve times during each
growing season at fruit set, the second fruit development stage, the beginning of the fruit color change and twice after month from harvest,
most protable treatment for peach trees grown under conditions of this investigation. This treatment gave the best vegetative growth, yield,
fruit quality, higher crop value with high net income /fed. from “Desert red” peach trees, in addition, reduced the percentage of double fruit
and deep suture by more than 50% in both seasons, therefore, the study recommends this treatment for “Desert red” peach growers.
Keywords: peach, tree growth, yield, fruit quality
Zayan, M.A., Mikhael, G. B. & Okba, S.K.
prevents alternate bearing and balances the fruit-to-shoot
ratio, leading to an increase in assimilates to fruits and shoots
so, peach fruit, thinning must be done every year (Costa et
al., 1983). It is recommended to thin at stage I because it
encourages cell division and expansion and leads to larger
fruit size (Westwood et al., 1967).
Also, foliar fertilization can play important role in
improving fruit quality by providing nutrients during a
critical phase of restricted nutrient supply(Veberič et al.,
2002b; Holb et al., 2009). The efciency of foliar applied
nutrients and their utilization is strongly depended on the
demand of a tree in the given phenological state and that
is nutrient specic (Weinbaum et al., 2002).From these
elements, potassium which transports sugars from leaves to
fruits so, it is very important during the fruit growth period
(Weinbaum et al. 1994). In addition, the importance of
potassium in improving quality (Ben et al (2009). Benlloch-
Gonzalez et al. (2008) afrmed that potassium increases
the ability of olive trees to withstand water stress. So, we
try to test the role of K+ spray (especially if it applies after
harvest during bud induction, particularly in Egypt where the
peach growers neglect the irrigation in these critical period.
This water stress may induce double fruit incidence in the
following season. There are other elements that can affect on
the yield and quality as P and N. In peach, P applications have
increased ower formation, whereas N was found to reduce
it (Fukuda & Kondo, 1957). Arora et al. (1999) concluded
that owering intensity, fruit set, fruit weight and fruit
yield were directly associated with leaf N content. Mineral
nutrition is a pre-harvest factor that affects fruit quality and
has to be performed very carefully since, after harvest, peach
quality cannot be improved but only maintained (Crisosto et
al., 1997; Holb et al., 2007).
Therefore, in this study, the goal was to study the effect of
thinning out pruning, fruit thinning and foliar application of
potassium silicate and super grow (20% N, 20% P2O5 and 20%
K2O )on yield and fruit quality and the relationship between
some nutrient balance and yield of “Desert red” peach trees.
Beside, testing the inuence of used treatments on both
physiological disorders, double fruit and deep suture %.
Materials and methods
The present investigation was carried out two successive
seasons 2014 and 2015 on ve years old Desert red peach
trees budded on Nemaguard rootstock and grown in sandy
soil at commercial orchard, Al-Nubaria city, El-Behira
Governorate-Egypt. The depth of water table was over 150
cm. The properties of the experimental soil are in Table 1.The
trees were planted at 4×5 m apart (210 trees/Fed.).Trees were
trained to open center vase and received the recommended
agricultural practices. Drip irrigation was used for irrigation.
Forty eight trees of similar size and shape were selected and
arranged in a randomized complete block design. The chosen
trees were grouped under eight treatments in each season.
Each treatment was represented by three replicate, two trees
per each. Table (2) summarize the eight applied treatments.
All obtained data were statistically analyzed using a
randomized complete block design according to Snedecor
and Cochran (1967).
The best date of foliar application after harvest has
been determined based on anatomical study in the previous
season of this investigation for determining the threshold of
bud initiation (according to Johansen, 1940 and Sass, 1958).
Flatting of doming meristem and receptacle primordial (R)
was noticed in 30 june 2013, while sepal (S) and petal (Pe)
primordial were Occurred in 15 July (As shown in Figs (1 & 2
& 3) ). Study these different stages of ower bud differentiation
is an important factor in orchard management for example
water stress in this time can be lead to decrease product and
increase fruit disorder as double fruit and deep suture percent
in next year (Handley and Scott Johnson, 2000).
Figure 1. Stage 1: undifferentiated meristematic apex (M)
(sampled, June 15, 2013)
Figure 2. Stage 2: atting of doming meristem-receptacle
primordium (R) (sampled, June 30, 2013)
Figure 3. Stage 3: leaves primordium (L), sepal primordial(S)-petal
primordial (Pe) (sampled, July 15, 2013)
Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence... 9
Measurements and determinations
Light penetration within tree canopy and between rows
Light intensity (Lux) was measured one time weekly
between 9-10 a.m from February to June using Luxmeter
(Pu-150) within the canopies of the trees adjacent to the
south side from axis (marked positions) at 3 levels: 0.5, 1.0
and 1.5 m from the top of trees, then mean values were used
for estimating light penetration at different distances as a
percent of full illumination at the top of the tree according to
Barritt et al. (1987).
Some vegetative growth parameters
Four main branches 2 years old on each tree in different
directions were labeled. All shoots which were developed on
these branches were counted and used for measuring Some
vegetative growth parameters i.e. length and number of
the new shoot were recorded at the end of each season, the
average length of nine shoots were recorded., then total shoot
growth (average shoot length × number of shoots/one-year
old branch). At mid July, Thirty mature mid – shoot leaves
were sampled measuring leaf area by using leaf area meter
model. Li 3100 area meter (LI-COR, Inc., Lincoln, Nebraska,
USA). Leaves were dried and weighted to get leaf dry weight
(g) and then, specic leaf weight (SLW) was calculated as
(mg/cm2) (mean leaf dry weight/average leaf area) according
to (Ferre and Forshey 1988). Also, number of leaves per fruit
(leaf/fruit ratio) was also estimated.
Leaf chlorophyll and mineral content
Fresh leaf samples were taken from each replicate
to determine chlorophyll a, b and then total value was
calculated according to Moran (1982). In mid July of both
seasons, fty mature mid shoot leaves per tree were sampled,
Table 1:Some chemical and mechanical analysis of experimental soil.
Soluble anions meq/lSoluble cations meq/l
(1:5 extract) So4--
Mechanical analysis, %
Soil textureTotal siltClayTotal sandFine sandMedium sandCourse sand
Table 2: Summary of used treatments
: - Thinning out 25% (p1) +fruit thinning 5 cm (FT1) at 30days after full bloom + no foliar spray (spraying water only)
: - Thinning out 35%(p35) + FT1 5 cm at 30 days after full bloom + no foliar spray
: - p1 + FT2 15 cm at 20 days after full bloom + no foliar spray
: - p2 + FT2 15 cm at 20 days after full bloom + no foliar spray
: - p1 + FT1 5 cm at 30 days after full bloom + foliar spray with two compounds (super grow 0.3% and potassium silicate 0.1%)
: - p2+ FT1 5 cm at 30 days after full bloom + foliar spray with two compounds (super grow 0.3% and potassium silicate 0.1%)
: - p1 + FT2 15 cm T at 20 days after full bloom + foliar spray with two compounds (super grow 0.3% and potassium silicate 0.1%)
: - p2+ FT2 15 cm at 20 days after full bloom + foliar spray with two compounds (super grow 0.3% and potassium silicate 0.1%)
P1: Thinning out 25% (p) by removing 25% of one year old shoots per tree at dormant (20th and 25th November) in 2014 and 2015 seasons, respectively.)
P2: Thinning out 35% (p) by removing 35% of one year old shoots per tree. (at dormant (20th and 25th November) in 2014 and 2015 seasons, respectively.)
FT1: Hand fruit thinning 5 cm at 30 days after full bloom
FT2: Hand fruit thinning 15 cm at 20 days after full bloom
No foliar spray: NO foliar application of potassium silicate and super grow (sprayed with water only)
Foliar spray: Foliar application of potassium silicate (25% S +10% K2O)at 0.1% and super grow compound (20% N + 20% P2O5+20% K2O)at 0.3% sprayed ve times during each
growing season at fruit set, the second fruit Development stage, the beginning of the fruit color change and twice after month from harvest.
Zayan, M.A., Mikhael, G. B. & Okba, S.K.
then washed three times with tap water, then washed again
by distilled water. Samples were oven dried at 70 0C to
constant weight, ground, digested with sulpharic acid and
hydrogen peroxide for the determination of N, P, K, Ca,
Mg, Nitrogen percentage was estimated by micro – kjeldahl
Gunning method (A.O.A.C., 1985). Phosphorus percentage
was determined colorimetically by the hydroquinone method
(Foster and Cornelia, 1967). Potassium concentration was
estimated by ame photometer E. Elmodel (Jackson, 1967).
Calcium, magnesium and manganese were determined by
using perkin Elmer Atomic Absorption Spectrophotometer
Model 2380 Al, according to (Jackson and Ulrich, 1959) and
(Yoshida et al., 1972). All macro elements were expressed as
percent of dry weight.
Yield data were determined in terms of: Number and
weight of fruit (kg) per tree and yield efciency (YE) as fruit
weight and number fruit per (cm2) of trunk cross section area
(TCSA) as kg/cm2, also kg.m-3 canopy volume and kg/m2 of
Physical fruit characteristics
Sample of 20 mature fruits were randomly harvested
from each replicate tree at the harvest time (May) and
used for determining average fruit weight (gm), size (cm3),
Length (cm), Diameter (cm), fruit shape (L/D),esh weight,
stone weight, esh/stone ratio, skin and esh rmness
using pentameter pressure tester Lb/inch2. Color of the
fruit was quantied at tristimulus colorimetery data (l,a,b)
using a Hunter colorimeter (Hunter lab. D 25L), color was
represented by L* (lightness), a* (green-red) and b*(blue-
yellow) scale readings. The hue angle (h0) was calculated
from arctangent b/a.the hue was represented as 00=red-
purple, 900=yellow, 1800=bluish-green
and 2700= blue. Chroma was calculated as
(a*2+b*2)1/2 (McGuire,1992 and Voss,1992).
Chemical fruit characteristics
10 fruits of each replicate were used to
determine each of the following characters:
total soluble solides of fruit juice (T.S.S %)
using a hand refractometer, fruit acidity (%)
as malic acid according to (A.O.A.C., 1985),
skin anthocyanin content (mg/gms F.W)
by using Carl-Zeiss Spectrophotometer
according to (Husia et al., 1965) and Vitamin
C content (ascorbic acid) was detemined as
mg/100 ml/of juice by titrating 5 ml. of the
juice with 2-6 di chlorophenol indopheol blue dye (Cox and
Percentage of double fruit and deep suture
Percentage of double fruit at thinning time was calculated
on 9 shoots per tree nal deep sutures percent was determined
by evaluating every fruit harvested in the third week of May
(Handly and Johnson, 2000).
Economic evaluation for different applied treatments was
compared according on the current prices under conditions
of this study.
Results and discussion
Light penetration within tree canopy
Data presented in Table 3 showed that the percentage of
light penetration at different vertical depth from the top of
tree canopy (0.5, 1.0 and 1.5 m) as affected by the conducted
treatments in 2014 and 2015 seasons. The data revealed
that increasing the depth from the top of desert red peach
tree canopy toward center decreased the light penetration
percentage . In most cases, the treatments including the high
level of thinning out (P 35%) had a tendency to increase this
percentage at different distances from the top of peach canopy.
In this respect, higher values were obtained by the T8 and T4
treatments than other treatments encompassing control. The
difference among treatments was signicant. These results are
in line with the ndings of Mika (1986) on apple, indicated that
light penetration had been enhanced by thinning out pruning.
Also, Mikhael et al. (2012) on Desert red peach trees, proved
that high level of thinning out improved the percentage of light
penetration as compared to low levels.
Table 3: Light penetration within tree canopy
Depth from the top of tree canopy toward center
Treatments 1.5 m1 m0.5 m
0.8412.801.1812.451.3110.79L.S.D at 5%
Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence... 11
Some vegetative parameters
Pointing the specic effect of the conducted treatments
on some vegetative growth parameters i.e. ( shoot length,
total shoot growth/ one-year old shoot and leaf area) as
shown in Table 4, in both seasons, the variation among
the treatments was signicant, the T8 and T6 treatments
succeeded in enhancing these parameters value as
compared with control. As for specic leaf weight, the
difference among the evaluated treatments was signicant
in rst season only and the highest values belonged to
T8,T6,T4,T2 without signicant difference among them in
comparison with the rest treatments including the control.
In general, the treatments involving high level of thinning
out pruning resulted in signicant increments in these
considered parameters(shoot length, total shoot growth/
one-year old shoot, leaf area and specic leaf weight).
This positive effect could be attributed to increase the
penetration of photosynthetic active radiation (Propiglia
and Barden, 1981) and increase in shoot hormone levels
(cytokinins, auxins and gibberellins) that can improve
these parameters (Tworkoshi et al., 2006). These results
are in harmony with those obtained by Zayan et al. (2002)
on apple and Mikhael et al. (2012) on Desert red peach
trees, they indicated that raising severity of thinning out
improved leaf and shoot parameters. As for the effect of
treatments on leaf/fruit ratio, in both seasons, control trees
attained signicantly lower value than T8 which presented
higher effect than all rest treatments. Treatments including
wider fruit thinning space( 15 cm distance) done early at 20
days after full bloom (DAFB) tended to increase this ratio
in comparing with the other treatment with narrower space
(5 cm distance) at 30 DAFB. These results agree with those
obtained by Zayan et al. (2015) on Florida prince, revealed
that higher levels of hand fruit thinning increased the leaf/
fruit ratio (Fig 4).
Table 4: Effect of different thinning out, fruit thinning and foliar spray treatments on some vegetative parameters
of “ Desert Red “ peach trees in 2014 and 2015
Specic leaf weight (mg/cm2)Leaf area (cm2)
Total shoot growth/one-year old
Shoot length (cm)
8.986.64b20.05e23.74f1.53e2.22d28.83c27.33 dT1 (Control)
N.S0.9802.291.841.431.257.364.83L.S.D at 5%
Fig 4: Effect of different thinning out, fruit thinning and foliar spray treatments on leaf / fruit ratio of “ Desert Red “ peach trees in 2014 and 2015.
Zayan, M.A., Mikhael, G. B. & Okba, S.K.
Leaf chlorophyll and macro-elements content
Signicant variation was observed among all evaluated
treatments in respect of total leaf chlorophyll value. The
results depicted in Table (5) exhibited that leaf chlorophyll
content was increased in severely-pruned trees (35%) in
the T8,T6,T4 and T2 treatments as compared to the control
which had light pruning degree (25%). The increase in
leaf chlorophyll might be resulted from modifying the top/
root ratio which enhanced the nutrients absorption via the
root and transfer them to the leaves which contribute in
the formation of chlorophyll molecular (Jundi, 2003 ) or
the nitrogen which sprayed to trees leaves participate in
building new chlorophyll molecular which led to increase
chlorophyll percentage in leaves. These conclusions were
also reported by Dinkova (1997) working on “Strinava”
plums, Al-Rawi et al. (2011) on apricot cv. Zaini and
Zayan et al. (2015) on “Florida Prince” peach cultivar
proved that the most pronounced effect in improving
chlorophyll value was observed with the high levels of
thinned out trees.
Leaf N content was signicantly affected by all conducted
treatments in both seasons, whereas the T8 treatment had a
remarkably effect than all treatments including the control.
Similar results were obtained by Abd El-Razek and. Saleh
(2012) on Florida Prince peach and Mosa et al. (2015) on
As for leaf phosphorous and K content, it was insig-
nicantly inuenced by the different applied treatments in
the rst season. In the second season, there were signicant
effects among the evaluated treatments. The T8, T7, T6,
and T5 treatments which received foliar application with
nitrogen, phosphorous and K, recorded remarkably higher
values than the control. The obtained results are in line with
the results of Zayan et al. (2015) on Florida prince peach and
Dbara et al. (2016) on peach cv. “Flordastar”, reported that
potassium leaf content was high in foliar potassium spray
The results of both seasons in Table (5) revealed that
the control, T2, T3 and T4 treatments recorded the lowest
signicant leaf Ca value in comparing the rest treatments in
most cases. It was observed that calcium leaf content was
lower with foliar application treatments (T5,T6,T7 and T8).
These results are in harmony with those of Mosa et al. (2015)
on Anna apple. As for leaf Mg %, in both seasons, the trees
of the control and T3 had signicantly lower effect than the
T8 treatment, the latest presented the same effect as the
T6,T7 in the rst season as well as T5,T4,T2 In the second
one. However, a tendency for higher Mg content was seen
in the samples from foliar application treatments in most
cases. These conclusions are in agreement with the results
of Zayan et al. (2015) on peach .From the above mentioned
results, the increase in the contents of N, P, K, and Mg in
the Desert red peach leaves was due to the foliar application
with potassium silicate (25% S +10% K2O)at 0.1% and super
grow compound (20% N + 20% p2O5+20% K2O) at 0.3%.
Regarding to leaf N/K ratio, the difference among
treatments was signicant only in the rst season, the highest
ratio belonged to T8 treatment in comparison to other
treatments involving the control except T6. Similar results
were obtained by Arora et al. (1999) on peach and . As for
leaf N/Ca+Mg ratio, in both seasons, T8 recorded higher
values than control and other treatments except T5 and T7 in
the second season. The variation among the tested treatments
was signicant in both season (Fig 5).
With regard to the inuence of the evaluated treatments
on desert red peach yield as number of fruits/tree, the data
in both seasons in Table (6) indicated that the control and
T5 trees carried signicantly the highest number of fruits/
tree with respect to other treatments due to the low degree
of fruit thinning, it was observed that increasing space of
fruit thinning with severe pruning reduced signicantly
the number of fruits/tree. Similar results were obtained by
Table 5: Effect of different thinning out, fruit thinning and foliar spray treatments on leaf chlorophyll and macronutrients content
of “ Desert Red “ peach trees in 2014 and 2015.
Total chlorophyllD.W %
L.S.D at 5%
Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence... 13
Abeer T. Mohsen (2010) on Flordaprince and Desert Red
peaches cultivars, and Deshmukh et al. (2012) on peach cv.
Flordasun. Mikhael et al. (2012) on Desert red peach trees,
revealed that pruning treatment signicantly reduced fruit
number and the reduction was increased as the severity of
As for the yield as kg/tree, in both seasons, the highest
signicant yield was weighed with T8 treatment in
comparison to the remaining treatments, followed by T7
treatment. The control and T2 treatments recorded the lowest
yield without signicant difference between them. These
results are in harmony with those of Zayan et al. (2015)
on peach cv Florida prince and El-Boray et al. (2013) who
reported that hand blossom thinning(HBT) of Florida prince
peach trees at 15 cm was the best treatment for yield per
feddan (6.08 tons for both seasons) as compared to control
and the low or high level of HBT (at 10 and 20 cm).The
resulted increase in yield as kg/tree could be attributed to the
increase in fruit weight resulting from the effect of widening
fruit thinning space with heavily pruning degree.
As for yield efciency (Y.E), in both season, the T8
treatment gave higher Y.E value whether as kg/m3 of canopy
volume or kg/m2 planting area than control and other
treatments except T6 in the second season, as shown in
Table 6.Concerning yield efciency as Kg/cm2 TCSA, in the
rst season T8 recorded higher value than other treatments
including the control except T3, while in the second one, the
control and T8 were statistically equal. The obtained results
are in line with those of Osborne and Robinson (2008) on
‘Rising Star’ peach variety.
Fig 5: Effect of different thinning out, fruit thinning and foliar spray treatments on leaf N/K and N/Ca+Mg ratio of “ Desert Red “
peach leaves in 2014 and 2015.
Table 6: Effect of different thinning out, fruit thinning and foliar spray treatments on yield of “ Desert Red “ peach trees in 2014 and 2015.
Yield Yield efciency (Y.E)
No. fruits/tree Kg/tree Kg/cm2 TCSA Kg/m3 of canopy volume Kg/m2 planting area
2014 2015 2014 2015 2014 2015 2014 2015 2014 2015
T1 (Control 255.67 272.5 18.58 19.61 0.171 0.132 0.934 0.967 0.93 0.98
T2 245.17 255.33 18.11 20.28 0.140 0.118 1.07b 1.18b 0.91 1.01
T3 226.30 239.00 21.09 22.77 0.184 0.132 1.00 1.16 1.05 1.14
T4 222.67 229.80 21.20 23.22 0.165 0.124 1.20 1.23 1.06 1.16
T5 254.83 269.83 19.84 24.04 0.150 0.145 1.08 1.15 0.99 1.20
T6 241.68 251.00 20.93 22.95 0.148 0.122 1.22 1.35 1.05 1.15
T7 232.33 252.30 23.55 26.26 0.165 0.135 0.986 1.19 1.17 1.31
T8 231.5c 250.67 25.69 29.09 0.207 0.156 1.47 1.51 1.29 1.45
L.S.D at 5 % 12.21 15.48 1.41 2.09 0.025 0.023 0.162 0.188 0.071 0.105
Zayan, M.A., Mikhael, G. B. & Okba, S.K.
Fruit physical characters
The data concerning the effect of different tested
treatments on fruit weight and size of “Desert red“ peach
presented in Table (7) and Fig (6) cleared that early heavily-
thinning (15 distance between fruits at 20 DAFB), severe
pruning and foliar application presented the superior effect
in this respect, in both seasons. The highest value always
belonged the T8 treatment, followed by T7. Meanwhile, the
control and T5 gave the lowest value in the rst season, while
the T1 (control) treatment only recorded the least weight
and size in the second one. The increase in fruit weight and
size as a consequence of high level of fruit thinning which
in turn led to improve leaf/fruit ratio. Thus increasing the
availability of photosynthates and nutrients to the remaining
fruits thereby increasing the weight and size of individual
fruits. Also, the increase in weight could be due to utilization
of whole food materials among the fewer fruits recorded
under severe pruned trees. In addition the role of potassium
in encouraging translocation complex sugars, may cause
modifying in osmotic pressure of the fruits and increase both
weight and size. Similar results were obtained by Sarkadi
(2012) on “Spring Lady” and “Maja” peach trees, El-Boray
et al. (2013) and Zayan et al. (2015) on Florida prince peach,
they concluded that fruit weight and size were improved
when the distance between the fruits on the mixed branch
Regarding to fruit rmness, conversely, the treatments
that received narrower fruit thinning at 5 cm between fruits
which done after 30 DAFB(days after full bloom) gave
higher values than those contained wider fruit thinning
space (15 cm) conducted after 20 DAFB. In this respect, the
control, T2, T5 and T6 increased fruit rmness comparing
with the remaining treatments. The reduction in fruit rmness
resulted from larger fruit size which in turn decreases the
strength of cell wall. Data in Fig (6 )support this explanation
Fig 6: Effect of different thinning out, fruit thinning and foliar spray treatments on fruit size of “ Desert Red “ peach trees in 2014 and 2015.
Table 7: Effect of different thinning out, fruit thinning and foliar spray treatments on some fruit physical properties
of “ Desert Red “ peach trees in 2014 and 2015
Fruit rmness Ib/in2
Fruit shape (L/D)Fruit diameter (cm)Fruit length (cm)Fruit weight (g)
1.711.730.1010.1020.423N.S0.4840.3996.967.16L.S.D at 5%
Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence... 15
meaning that fruit size and fruit rmness are negatively and
signicantly correlated in both seasons at level 0.05, the
value of Correlation coefcient (r) was -0.927 and -0.726 in
2014 and 2015 season, consecutively (p value 0.707). The
present results are in close conformity with the ndings of
Abeer T. Mohsen, (2010) on “Florda prince and Desert Red”
Peaches, Deshmukh et al. (2012) and Meitei et al. (2013),
on peach cv. Flordasun, El-Boray et al. (2013) on “Florida
prince “peach, they indicated that increasing the distance
between fruits by early fruit thinning reduced fruit rmness.
As for fruit dimension, in both seasons, the highest fruit
length (L) was obtained by control which had light pruning
(25%) in comparison with all rest treatments except T3 and
T5 (25%) in the rst season. This might be due to the fact
that under light pruning there was less light penetration and
auxin level causes organ cells on the dark side to elongate
under light pruning. The average of fruit diameter (D) was
signicantly affected in the second season only. The heavily-
pruned trees (35%) in T8 treatment had the highest signicant
effect comparing with the other treatments except,T4 and T6
treatments which had the same degree of pruning. Also, it
was observed that there was a progressive increase in fruit
diameter with the increasing fruit thinning space, severity of
pruning and early fruit thinning at 20 days after full bloom.
As for L/D ratio, it takes similar trend as observed in fruit
length. These results are in harmony with those obtained by
Olmstead et al. (2011), on different varieties (‘Flordaprince’,
‘Tropicbeauty’ and ‘UFBeauty’), Deshmukh et al. (2012), on
peach cv. Flordasun and Mikhael et al. (2012) on Desert red
Chemical fruit properties
Data in Table (8) showed that the signicant variation was
observed among all evaluated treatments in both seasons.
Fruit soluble solids content (SSC) and SSC/Acid ratio were
higher in fruits received early heavily-thinned trees (T8,
T7,T4 and T3) as compared to late lightly-thinned one (the
control, T2, T5, T6). In most cases, increasing fruit thinning
space between fruits on one-year old shoot from 5 cm to
15 cm apart and doing it early at 20 DAFB with applying
foliar spray enhanced these parameters. Improvement the
soluble solids content could be attributed to increasing
leaf/fruit ratio,leading to more accumulation of sugars in
the developing fruits. In addition, the pivotal importance
of potassium in quality formation stems from its role in
enhancing synthesis of photosynthates and their transport to
fruit (Rania . A. Taha et al., 2014).
In regard to fruit acidity, it was signicantly affected
only in the second season It was observed that fruit acidity
% tended to be lower for trees treated with fruit thinning 20
DAFB at 15 cm between fruits(T8,T7,T4 and T3). Reduction
in acidity might be attributed to the increase in fruit size,
this conclusion nd support in the data presented in Fig (6).
Similar results were obtained by Abeer T. Mohsen, (2010)
on Florida prince and Desert red cultivar and El-Boray et
al. (2013) on Florida prince peach cultivar. In contrary,
those treatments (T8,T7,T4 and T3) had signicant effect on
fruit vitamin c content than other treatments(the control,
T2,T5,T6) which recorded the least value in this respect
without signicant difference among them. Increasing in
ascorbic acid might be due to the increase in leaf /fruit ratio
(as shown in Fig 4). The obtained results agree with the
ndings of Deshmukh et al. (2012) on peach cv. Flordasun,
mentioned that the ascorbic acid content was recorded the
highest value with 55:1 leaf fruit ratio treatment followed by
45:1 while the lowest content was recorded in control.
Hunter color values (L, a, b, Hue and chroma)
Color parameters of Desert red peach samples are shown
in Table 9. Lightness of desert red peach was affected
signicantly by all tested treatments in both seasons. Lower
lightness value (fruit became darker)was lesser with the
T2,T8, T5,T6 as well as T4 treatments in the second season only
than the control which showed similar effect as T3. It was
clear that darker fruit were obtained by increasing pruning
severity in most cases. As for a * values(redness), In most
cases, the T8,T7 gave higher increase than control which
had the same effect as the T3,T4 and T6 treatments in the two
experimental seasons. With regard to color reectance for
Table 8: Effect of different thinning out, fruit thinning and foliar spray treatments on some fruit chemical properties
of “ Desert Red “ peach trees in 2014 and 2015
(mg/100 ml juice)
SSC/Acid ratioAcidity %SSC %
1.351.334.123.910.292N.S1.390.933L.S.D at 5%
Zayan, M.A., Mikhael, G. B. & Okba, S.K.
yellowness (b* value), fruits from control trees enhanced
this value in comparison to T2,T4,T6,T8 treatments during
both seasons. Moreover, there were no signicant difference
among the control, T3 and T7 treatments .It was observed
that increasing thinning out pruning severity degree from
25% to 35% registered lowest hue angle(fruit became more
red and less yellow) and reduced chroma (brightness or color
intensity).Accordingly, heavily-pruned trees(35%) in the
T8,T4,T2,T6 treatments resulted in lower values than control
in this respect in most cases. The improvement in color
values could be attributed to the important role of pruning
in increasing the degree of light penetration which in turn
accelerate higher accumulation of pigments responsible for
the fruit color. Similar results were obtained by Lewallen
(2000) ‘Norman’ and ‘Cresthaven’ peach, found that
position of the fruit on the tree also affected fruit quality
characteristics; peaches from the medium pruning intensity
and outer canopy were redder and darker than those from the
lower canopy . Furthermore, Mikhael et al. (2012) on Desert
red peach cultivar who revealed that increasing pruning
intensity degree increased the percentage of skin red color.
The data of the two experimental seasons concerning
fruit anthocyanin content, in Table (9) cleared that it was
signicantly varied by different tested treatments. Fruits from
trees treated with thinning out pruning 35% + fruit thinning
15 cm at 20 days after full bloom + foliar spray with two
compounds (super grow 0.3% and potassium silicate 0.1%
(T8) produced maximum value in comparison with all other
treatments including the control except T6,T4 in the rst
season.. Increasing anthocyanin content could be explained
by the degree of pruning which allows fruits to be exposed
to large amount of light, causing the accumulation of color
compounds. In addition the role of potassium in enhancing
anthocyanin accumulation and red coloration by encouraging
translocation complex sugars that important for anthocyanin
synthesis to fruits (Ritenour and Khemira, 1997), also the
effect of heavily-fruit thinning in increasing L/F ratio may
be effective in anthocyanin concentration in peach fruits
.These conclusions nd support in the results of Samira, M.
Mohamed et al., 2014) and Zayan et al. (2015) on Florida
prince peach cultivar, they reported that anthocyanin content
of Florida Prince’ peach fruits enhanced by increasing
severity of pruning treatments. Moreover, Deshmukh et al.
(2012) revealed that increasing the leaf/fruit ratio to some
extent (45:1) improved anthocyanin content of “Flordasun
Physiological disorders; Double fruit and deep sutures %
The data presented in Table (10) demonstrated that
there were signicant difference among the evaluated
treatments on the percentage of double fruit and deep sutures
disorders. In addition, there was a noticeable trend that foliar
application treatments reduced the incidence of double fruit
and deep suture, this reduction reached the least values with
the T8,T7,T6and T5 treatments in most cases during both
seasons. The reduction in double fruit and deep sutures %
might be attributed to potassium’s role in drought tolerance
by improving water-use efciency, leaf water content and
reducing transpiration rates (Arquero et al., 2006). These
data support the fact that high temperatures and water
stress during the early stages of the morphological pistil
differentiation have a limiting factor for double fruit disorder
incidence.( Handley and Johnson (2000) and Engin & Unal
(2005). Both disorders in Desert red peach variety could be
managed by the balanced irrigation regime, particularly at
the time of bud differentiation.
Table 9: Effect of different thinning out, fruit thinning and foliar spray treatments on fruit color of “ Desert Red “ peach trees in 2014 and 2015.
Anthocyanin mg/100g fresh
0.4610.3934.234.463.684.522.872.85L.S.D at 5%
L* (lightness), hue0= arctangent b/a & Chroma =(a*2+b*2)1/2
Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence... 17
Table (10): Effect of different thinning out, fruit thinning and foliar spray
treatments on two physiological disorders; Double fruit and deep sutures %
of “Desert Red “ peach trees in 2014 and 2015.
Deep suture %Double fruit %
4.112.9314.388.81L.S.D at 5%
Economic evaluation of the tested treatments in this
study was done to put light on the best treatment obtained
to be recommended for peach growers. The evaluation
depended on estimating the total costs, crop value and net
income per feddan, as shown in Tables (11 & 12). Total costs
include prices of (potassium sulphate, ammonium nitrate,
phosphoric acid, magnesium sulphate, chelates nutrients,
potassium silicate, pesticides, harvest cost, maintenance
and fuel irrigation machine, thinning out and fruit thinning
costs). The results showed that, total costs/fed for the control,
T2, T3 and T4 treatments (2354.38 L.E) were similar and
lower than the total costs in the T5, T6,T7 and T8 treatments
(2665.63 L.E) which were the same due to the cost of
foliar application with potassium silicate and super grow
substances.. Concerning crop value /fed., the highest record
was obtained from trees treated with thinning out 35% +
Fruit thinning at 15 cm at 20 days after full bloom + foliar
spray with two compounds (super grow 0.3% and potassium
silicate 0.1% (T8). This value reached (34619.44 & 38596.92
L.E/Fed.) while the lowest record resulted from the treatment
No. 1 (the control) (15608.47 & 18.527.92L.E/Fed) in both
seasons, respectively. Concerning, net income /fed., the
treatment No. 8 gave the higher return (35104.23& 40100.51
L.E/Fed) whereas the lowest return resulted from the control
treatment (13255.09 & 16173.54L.E) in 2014 and 2015
seasons, respectively. Thus, it could be concluded that the
greatest return came from treatment No. 8 which improved
fruit qualities, increased net income per/fed (Table 12).
Table 11: The current prices of all production materials used under this study
Material Price (L.E)
• 1 L potassium silicate (4 L/fed)
• 100g of super grow compound (1.312 kg/fed)
• Labor costs
• Costs of maintenance and fuel irrigation machine
• Pesticides costs including (Sidial, mineral oil, Oxy chloro copper, Malathion chelated fertilizers Costs
• costs of fertilizers including ( potassium sulphate + ammonium nitrate + phosphoric acid + Magnisium sulphate)
• 1 ton fruit yield of T8 and T7
• 1 ton fruit yield of control
• 1 ton fruit yield of T4
• 1 ton fruit yield of T3, T5 and T6
4000 (2014) & 4500 (2015)
Table 12: Economic evaluation of the evaluated treatments (L.E/Fed) in 2014 and 2015.
Net income/ fedCrop value/fed
2015201420152014Other costsUsed treatments
Zayan, M.A., Mikhael, G. B. & Okba, S.K.
Based on the obtained results in this study, it could be
concluded that application of thinning out pruning 35%,
fruit thinning by leaving 15 cm between fruits on one-year
old shoot at 20 days after full bloom and foliar application of
potassium silicate and super grow compound which sprayed
ve times during each growing season at fruit set, the second
fruit development stage, the beginning of the fruit color
change and twice after month from harvest was the most
protable treatment for peach trees grown under conditions
of this investigation. This treatment (T8) is recommended
for peach growers to obtain the best vegetative growth,
maximum fruit yield with good quality fruits, higher crop
value with high net income /fed. from Desert red peach trees,
in addition, reducing the percentage of double fruit and deep
suture disorders by more than 50% in both seasons.
Abd El-Megeed, N.A.M. (2001): Effect of hand and chemical
thinning on yield, fruit quality, storage and marketability of some
peach varieties. Ph. D. Thesis, Alex. Univ. Alex. Egypt.
Abd El-Razek, E. and M.M.S. Saleh. (2012): Improve productivity
and fruit quality of Florida prince peach trees using foliar and soil
applications of amino acids. Middle-East J. Sci. Res., 12 (8): 1165-
Abeer T. Mohsen. (2010): Thinning Time and Fruit Spacing
Infuence on Maturity, Yield and Fruit Quality of Peaches. Journal
of Horticultural Science & Ornamental Plants 2 (3): 79-87.
Al-Rawi, A.W., A. M. Helmi, N. A. Jasim and F. F. Jomaa. (2011).
Effect of winter pruning and Enfaton on yield and carbohydrates
content of branches of apricot. The Iraqi Journal of Agricultural
Sciences 42 (2): 35-70.
A.O.A.C. (1985): Association of Ofcial Agriculture Chemistry,
Ofcial Methods of Analysis. Washington, D.C., U.S.A.
Arora R.L., S. Tripathi and S. Ranjeet. (1999): Effect of nitrogen
on leaf mineral nutrient status, growth and fruiting in peach. Indian
Journal of Horticulture Vol. 56 (4): 286-294.
Arquero, O., D. Barranco and M. Benlloch. (2006): Potassium
starvation increases stomatal conductance in olive trees
HORTSCIENCE, 41 (2): 433–436. 2006.
Barritt, B. H., C.R. Rom, K.R. Guelich, S.R. Drake and M.R.
Dilly. (1987): Canopy position and light effects on spure, leaf and
fruit characteristics of “Delicious” apple. HortScience, 22: 402-405.
Ben M. M., M. Ghrab, M. Ghanem and O. Elloumi (2009):
Effects of Potassium foliar spray on olive, peach and plum. Part 2:
peach and plum experiments. Research ndings: Optimizing crop
nutrition. 19: 14-17.
Benlloch-Gonzalez M., O. Arquero, J.M. Fournier, D. Barranco
and M. Benlloch. (2008): K+ starvation inhibits water-stress-
induced stomatal closure. J Plant Physiol 165: 623-630.
Byers, R.E., G. Costa and G. Vizzotto (2003): Flower and fruit
thinning of peach and other Prunus. Hort. Rev. 28:285-292.
Costa, G., C. Giulivo and A. Ramina (1983): Effects of the
different ower/vegetative buds ratio on the peach fruit abscission
and growth. Acta Hortic 139: 149–160.
Cox, H.F. and D. Pearson. (1962): The chemical analysis of foods,
136-144. Chem. Publishing Co.Inc. New York, N.Y.
Crisosto C.H., R.S. Johnson, T. Dejong and K.R. Day.
(1997): Orchard factors affecting postharvest stone fruit quality.
HortScience, 32: 820–823.
Dbare, S., T. Gader and M. B. Mimoun (2016): Improving yield
and fruit quality of peach cv. ‘Flordastar’ by potassium foliar spray
associated to regulated decit irrigation. Journal of new sciences,
Agriculture and Biotechnology, 28 (10): 1631-1637.
Deshmukh, N.A., R.K. Patel, B.C. Deka, A.K. Jha and P.
Lyngdoh (2012): Leaf to fruit ratio affects fruit yield and quality of
low chilling peach cv. ‘Flordasun’. Indian Journal of Hill Farming,
25 (1): 31-34.
Dinkova, S. (1997): Effect of pruning intensity on the pigment
content and leaf size of plum Rasteniev. Dni Nauki, 32 (5): 255-256.
El-Boray, M.S., A.M. Shalan and Z.M. Khouri (2013): Effect of
different thinning techniques on fruit set, leaf area, yield and fruit
quality parameters of Prunus persico, L. Batsch cv. Floridaprince.
Trends Hortic. Res., Vol. (3): 1-13.
Engin, H. and A. Unal (2005): The effect of irrigation, gibberellic
acid and nitrogen on the occurrence of double fruit in ‘Van’ sweet
cherry. Acta Horticulturae (ISHS) 795: 645-651.
Erez, A. and J.A. Flore (1986): The quantitative effect of solar
radiation on ‘Redhaven’ peach fruit skin color. HortScience 21:
FAO (2013): Food and Agriculture Organization of the United
Nations Internet site. Agricultural statistics. www.fao.org. Spt.
Ferre, D.C. and C.G. Forshey (1988): Inuence of pruning and
urea spray on growth and fruiting of square bound Delicious apple
trees. J. Amer. Soc. Hort. Sci. 113 (5): 699-703.
Foster D.S. and Cornelia T. S. (1967): Colormetric methods of
analysis. D.Van Nestrant Company Inc. (551-552).
Fukuda, A. and G. Kondo (1957): Growth and yield as related to
the concentrations of nitrogen, phosphoric acid, and potassium in
sand culture. Studies Inst. Hort. Kyoto Univ., 8: 16–23.
Handley, D. F. and R. S. Johnson (2000): Late summer irrigation
of water-stressed peach trees reduces fruit doubles and deep Sutures.
Hortscience 35 (4): 771.
Holb, I.J., Gonda, I., Vago, I., Nagy, P.T. (2009): Seasonal
dynamics of nitrogen, phosphorus, and potassium contents of leaf
and soil in environmental friendly apple orchards. Communications
in Soil Science and Plant Analysis, 40: 694-705.
Husia, C. L.; B. S. Luh and C. D. Chichester (1965): Anthocyanin
in free stone peach. J. Food Science, 30: 5-12.
Chartzoulakis, K.; I. Therios and B. Noitsakis (1993): Effects
of shading on gas exchange, specic leaf weight and chlorophyll
content in four kiwifruit cultivars under eld conditions. J. Hortic.
Sci., 68 (4): 605–611.
Jackson, M.L. (1967): Soil chemical analysis. Prentice Hall Inc.
Engle wood cliffs, N.S.
Johansen, S. (1940): Plant microtechnique. Mc Graw-Hill Book
Company, New York.
Jackson, M.L. and A. Ulrish (1959): Analytical methods for plant
analysis. Coll. of Agric. Exp. State Bull. 766: 35 pp.
Jundi, H. M. (2003): Physiology of tree fruits. Arabic home for
Kader, A. (2002): Postharvest technology of horticultural crops.
Publication 3311. USA, University of California Agricultural and
Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence... 19
Lewallen, K. A. S. (2000): Effects of light availability and canopy
position on peach fruit quality. MSC the Faculty of the Virginia
Polytechnic Institute and State University, Blacksburg, Virginia.
Marini, R.P. and D.L. Sowers (1994): Peach fruit weight is
inuenced by crop density and fruiting shoot length but not position
on the shoot, J. Am. Soc. Hortic. Sci. 119 (2): 180–184.
McGuire, R.G. (1992): Reporting of objective color measurements.
HortScience 27: 1254–1255.
Meitei, S. B., R. K. Patel, B.C. Deka, N. A. Deshmukh and A.
Singh (2013): Effect of chemical thinning on yield and quality of
peach cv. Flordasun. African Journal of Agricultural Research Vol.
8 (27): 3558-3565.
Mika, A. (1986): Physiological responses of fruit trees to pruning.
Hort. Rev., 8: 337-378.
Mikhael, G.B., A.K. Omar and M.A. Gabr (2012): Yield and
fruit quality of “Dessert Red” peach trees as inuenced by planting
density and pruning severity. J. Biol. Chem. Environ. Sci., 7 (2):
Moran, R. (1982): Formulae for determination of chlorophyllous
pigments extracted with N, N. Dimethyl formamide. Plant physiol,
Mosa, W. F., N. A. Abd EL-Megeed and L. S. Paszt (2015): The
effect of the Foliar application of potassium, calcium, boron and
humic acid on vegetative growth, fruit set, leaf mineral, yield and
fruit quality of ‘Anna’ apple trees. AJEA, 8 (4): 224-234.
Olmstead, M., G. England and R. Atwood (2011): Optimizing
Fruit Spacing in Florida Peach Production.Proc. Fla. State Hort.
Soc. 124: 41–44.
Osborne, J.L. and T. Robinson (2008): Chemical peach thinning:
Understanding the relationship between crop load and crop value.
New York Fruit Quarterly, 16: 19–23.
Porpiglia, P. J. and J.A. Barden (1981): Effect of pruning on
penetration of photosynthetically active radiation and leaf physiology
on apple trees. J. Amer. Soc. Hort. Sci., 106 (6): 752-754.
Rania A. Taha, H.S.A. Hassan and E.A. Shaaban (2014): Effect
of different potassium fertilizer forms on yield, fruit quality and leaf
mineral content of Zebda mango trees. Middle-East J. Sci. Res., 21
Ritenour, M. and H. Khemira (1997): Red colour development
of apple, a literature review. Washington State University, Tree
fruit research & Extension center.Pages:1-10.Available at (http://
Samira, M. Mohamed, T.A. Fayed, A.M. Hussein and Safaa M.
Maged (2014): Effect of some pruning applications on leaf to fruit
ratio, yield and fruit quality of ‘Florda Prince’ peach trees. J. Hort.
Sci. & Ornamen. Plants, 6 (1): 18-26.
Sarkadi, B. I. (2012): Study upon the impact of chemical thinning
with ethephon on the quality of two peach varieties cultivated in
the Western part of Romania. Int. Res. J. Agric. Sci. Soil Sci., Vol.
2 (9): 413-420.
Sass, J.E. (1958): Elements of botanical microtechnique, vol 2.
Mac Graw-Hill Book Company, New York.
Schnabel, G., Layne, R.D., Holb, I.J. (2007): Micronised and
non-micronised sulphur applications control peach scab equally
well with negligible differences in fruit quality. Annals of Applied
Biology 150 (2): 131-139.
Shaltout, A.D. (1995): Introduction and production of some low-
medium chill peach cultivars in the sub-tropical climate of Egypt.
Assiut. J. Agric. Sci., 26 (1): 195-206.
Shiukhy, S., M. R. Sarjaz and V. Chalavi (2014): Evaluation of
chlorophylls activity, carotenoids content and total anthocyanin
changes of fruit in different aspects and fruit location within orange
tree canopy. J Nov. Appl Sci., 3 (S2): 1578-1583.
Snedecor, G.A. and W.G. Cochran (1967): Statistical Methods. 6th
Ed. Lowastate. Univ., Lowa, U.S.A.
Tworkoshi, T., S. Miller and R. Scorza (2006): Relationship
of pruning and growth morphology with hormone ratio in shoots
of pill and standard peach trees. J. Plant Growth Regul., 25:
Veberič, R., D. Vodnik and F. Stampar (2005): Inuence of
foliar-applied phosphorus and potassium on photosynthesis and
transpiration of ‘Golden Delicious’ apple leaves (Malus domestica
Borkh.): Acta Agriculturae Slovenica, 85 (1): 143–155.
Veberič, R., F. Štampar and D. Vodnik (2002b): Inuence
of the foliar application of phosphorus and potassium on the
photosynthetic intensity in apple trees (Malus domestica Borkh.):
Acta Horticulturae, 594: 165-170.
Weinbaum, S.A., F.J.A. Niederholzer, S. Pochner, R.C.
Rosecrance, R.M. Carlson, A.C. Whittlesey and T.T. Muraoka
(1994): Nutrient uptake by cropping and defruited eld grown
“French” prune trees. J Amer Soc. Hort. Sci., 119: 925-938.
Weinbaum, S.A., P.H. Brown and R.S. Johnson (2002):
Application of selected macronutrients (N, K) in deciduous
orchards: physiological and agrotechnical perspectives. Acta
horticulturae 594: 59-64.
Westwood, M. N., L.P. Batjerand and H.D. Billingsley (1967):
Cell size, cell number, and fruit density of apples as related to fruit
size, position in cluster, and thinning method. Am. Soc. Hort. Sci.
Yoshida, S., D.A. Forno, J.H. Cock and K.A. Gomez (1972):
Laboratory manual for physiological studies of rice. The
International Rice Research Institute Los Banas . Philippines.
Zayan, M.A., E. Morsy, H.M. Ayaad and M.A. Gabr (2002):
Inuence of pruning treatments on growth, leaf constituents,
owering, yield and fruit quality of “ Anna” apple trees. 2nd
Inter. Conf. Hort. Sci.Kafr Elsheikh, Tanta Univ., Egypt,
Zayan,M.A., S.M. Zeerban, G.B Mikhael and H.M. Abo Ogiela
(2015): Improving productivity and fruit quality of Florida prince
peach trees by using some agriculture treatments.