1. The document discusses chemical crop regulation methods in fruit crops, focusing on regulating flowering, fruiting, water and nutrient management, and yield through chemical applications. 2. Various chemicals like paclobutrazol, NAA, ethephon, Armothin, ATS, and hydrogels are described as being used to regulate flowering timing, increase fruit set and retention, thin blossoms, and improve water and nutrient uptake to increase yields. 3. A case study evaluates the efficacy of the chemical thinner Brevis on apple trees, finding that multiple applications resulted in lower fruit set and crop load than single applications or the control.

1. 1
WELCOME

2. Sri Konda Laxman Telangana State Horticultural
University
College Of Horticulture, Rajendranagar, Hyderabad
Submitted by:
Y. Pooja,
RHD-19/07,
Department of Fruit Science.
Submitted To:
Smt. Naga Harshitha,
Asst. Professor,
Department of Fruit Science.
Topic:
Chemical Crop
Regulation in Fruit
Crops

3. 1. Introduction to crop regulation
2. Need of crop regulation
3. Methods & objectives of crop regulation
4. Chemical regulation in
i. Flowering
ii. Fruiting
iii. Water management
iv. Nutrient management
v. yield
4. Case study
5. Conclusion
6. Reference
3
Out line

4. 1. The main objective of growth regulation practice (crop
regulation) is to force the tree for rest and produce profuse
blossoms and fruits during any one of the two or three flushes.
2. The basic principle of crop regulation is to manipulate the
natural flowering and fruiting of fruit crops in desired season of
the year that contribute to increased fruit yield, quality.
3. Crop regulation done by physical and chemical methods
4. Through chemicals we can regulate flowering, fruiting, water
management, nutrient management and yield.
4
Crop regulation

5. 1. Many crops which bloom more than one in a year do not produce
good yield and quality of the fruit throughout the year. The yield and
quality depends on the bahar.
2. For example, the rainy season crop of guava is poor in quality and
crop is affected by many biotic and abiotic stresses as compared to
winter season crop.
3. The winter season crops (mrigbahar) which ripen from second
fortnight of October to first fortnight of January are superior in
quality, free from diseases and pests and fetch higher income. This
requires regulation of flowering (from ambebahar to mrigbahar) to
obtain most profitable crop by several methods. In different regions
various methods of crop regulations are followed depending on
climatic factors, cropping pattern, cultivar etc.
4. The flowering is more in guava during summer season because of
heavy new flushes that lead to more fruit production in rainy season.
5
Need of Crop Regulation

6. 4. In this season, duration of fruit harvesting is reduced to 30 days
due to high temperature and rainfall and it causes glut in the
market which lead to poor price and less demand in the market.
5. Winter season crop is superior in quality which fetches higher
prices than rainy season crop. In rainy season there is a serious
attack of fruit flies which deteriorates its quality and fruits
become unfit for human consumption. So far getting the
quality fruits in guava only winter season crop.
6. should be taken and rainy season crop should be avoided. Water
availability is big issue in Maharasthra, Rajsthan and Gujrat
during summer season for pomegranate grower. They always
avoid taking ambebahar crop and regulating this crop in to
mrigbahar with the onset of monsoon and crop is harvested
during winter and some farmers prefer hasthbahar with less
availability of water.
6

7. Methods of crop regulation :
• In order to get only appropriate season crop it is necessary
to manipulate the flowering. The following practices can be
adopted:
1. Deblossoming or Thinning (Physical/ Chemical)
2. Withholding of irrigation (Physical)
3. Root exposure and root pruning (Physical)
4. Shoot Pruning (Physical)
5. Chemical/PGRs application (Chemical)
6. Nutrients application (Chemical)
7. Shoot bending (Physical)
7

8. Objectives of crop regulation:
1. The main objective of crop regulation is to force the tree for
rest and produce profuse blossom and fruits during any one
of the two or three flushes.
2. To regulate a uniform and good quality of fruits and to
maximize the production as well as profit to the grower.
3. To reduce cost of cultivation because uninterrupted
continuous blossom would produce light crops over the
whole year and require a high cost for the monitoring and
marketing.
8

9. 9
Flower initiation defined as the morphological changes
that make meristems to specify flower meristems, is
immediately followed by the development of flowers.
Therefore, flower initiation can be considered the crucial
regulatory point on which selection acts to ensure flowering
and fruiting on time.
 Effect of Chemicals on :
i. Flower drop
ii. Early Flowering
iii. Flower thinning
Effect of chemicals on flowering

10. 10
Fruit set improving plant growth regulators minimum number of days was
recorded in untreated control (P0) (49.66), followed by NAA (P2)
(54.83).Maximum number of days was recorded in application of paclobutrazol
(P1) (58.83). Paclobutrazol could not able to reduce the time taken for fruit set
after panicle initiation compare to control. However, increase in days taken for
fruit set from panicle initiation might be beneficial for better fruit set and fruit
retention in paclobutrazol treated trees.
Early Flowering:
Vijay et al., 2016.

11. 11
Paclobutrazol increases the fruit setting due to its anti - gibberellin activity
(Quinlan and Richardson, 1984). Hence, in the present investigation the
increase in the percent (%) flowering of mango by paclobutrazol was due to
its anti - gibberellin activity. The similar findings of increase in per cent
flowering (%) by application of PBZ was earlier reported by Kumar Raj et al.
(2005) in mango cv. Baneshan, Vijay et al., 2016.
Number of Flowers:

12. Flower thinning
Most chemicals that have been tested and found effective in preventing
apple flowers from setting fruits work by desiccating the flower organs
and preventing pollination and/or fertilisation (fruit set).
Ammonium thiosulphate (ATS) for blossom thinning
1. The foliar nutrient ATS has a very useful side effect as a blossom
thinner on apples and other crops. If applied at flowering time, ATS
works by desiccating and, therefore, damaging the stigmas and
styles of apple flowers, so preventing them from setting fruits.
2. When using ATS as a blossom thinner on apples it is important to
consider:
i. Spray timings
ii. The ideal weather conditions
iii. Spray concentrations and volumes
iv. Use of adjuvants
V. Variations associated with specific varieties
12

13. • Armothin
1. Armothin is a surfactant manufactured by the Azco-Nobel Co
Ltd, which has showed useful activity as a blossom thinner on
stone fruits. It is a 98% fatty amine polymer.
2. In trials at East Malling, high volume sprays (1000 l/ha) of
Armothin at 0.5% active ingredient were tested at three timings,
balloon blossom, 5 days after full bloom on the two-year-old
spurs or 10 days after full bloom.
3. The trees used for the test were eight-year-old Royal Gala on M.9
rootstock.
4. Concern was expressed by the chemical manufacturers about
possible fruit russeting.
5. To counteract this a programme of Regulex (GA4+7) was applied
to some of the Armothin treated trees.
6. A second trial on Royal Gala also included sprays of Armothin,
applied 10 days after full bloom. The results of the two trials
were inconsistent.
13

14. 1. In one trial no significant thinning was achieved, whilst in the
other, mean fruit size and grade out was improved in comparison
with unsprayed controls.
2. No significant phytotoxic damage was recorded, irrespective of
whether the treatments were supplemented by Regulex sprays or
not.
3. A third trial conducted on the variety Jonagold was also
disappointing with only minimal thinning following the Armothin
sprays.
4. On this limited preliminary evidence, Armothin appears to hold
only minimal promise as a potential blossom thinner for apples
under UK conditions.
5. ‘Armothin’ has proved an effective thinner for stone fruits in
Italian trials.
6. In UK trials on apples it gave inconsistent results as a flower
thinner.
7. ‘Armothin’ is not approved currently for use as a flower thinner
in UK orchards.
14

15. Ethephon
1. Ethephon (Ethrel C) has been tried on many occasions
as a blossom thinner for apples.
2. Temperatures lower than 15oC result in poor efficacy
of thinning; thinning increases linearly as
temperatures increase from 12-24oC.
3. In regions of the world where temperatures during
blossom time are >15oC, sprays of ethephon in water
with a slightly alkaline pH often give consistent
beneficial effects in apple flower thinning.
4. Where temperatures are lower, the thinning response
to ethephon is usually variable and often very poor.
5. Ethephon is cleared for use as a thinner in several
European countries but is not approved currently for
use as a flower thinner in UK orchards.
15

16. 16
Effect of chemicals on Fruit setting
Maximum fruit set per panicle was recorded in application of
paclobutrazol (P1) (5.95), followed by application of NAA (P2)
(5.61).Minimum fruit set per panicle observed in untreated control
(P0) (5.36) Similar increase in fruit set per panicle in response to
paclobutrazol application was recorded by Kumar Raj et al. (2005) in
cv. Baneshan
Vijay et al., 2016.

17. • The sprayed materials (NAA + Zn + Ca + B) had a positive effect
on fruit set, fruit drop and fruit retention, also in reducing
malformed panicles percentage.
• On the other hand, the used materials increased yield of Alphonso
mango trees especially when sprayed in combinations, since
treatment Zn + Ca gave the highest value and increased tree yield
by about 445 and 435% than the control in the first and second
seasons, respectively, followed by treatment included all sprayed
materials Zn + Ca + NAA +B. As for fruit quality (physical and
chemical properties), it’s clear that spaying Zn, Ca, B and NAA
gave a high quality comparing with the control.
• Concerning leaf mineral content, treatments included more than
two spraying materials gave higher values than those included
two or single material including the control.
17
Merwad et al., 2016.

18. 18
Effect of BA spray

19. Effects of combinations of ATS and BA on the fruit set, yield and
fruit size of Royal Gala
19

20. 20
Effect of chemicals on Yield
Among flower enhancing plant growth regulators maximum weight was
recorded in application of NAA (P2) (302.08). Minimum fruit weight
was recorded in untreated control (P0) (269.74),
Vijay et al., 2016.

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• Effect of the hydrogel in retaining the water: Hydrogel polymers
are synthetic chemicals improve water penetration rate, hydrogel
polymer have been used as water retaining material in arid and
semiarid region under limitation of supplementary irrigation sources
and salinity conditions which affect negatively on gradual growth
and productivity of crops, hydrogel used to increase a water
reservoir near the root zone and increased the field capacity of
different soils, also, increased both water available for plants and the
period of its availability (Montesano et al., 2015)

22. 22
Barak et al., 2015.

23. 23
• Hydrogel polymers are chemicals which improve water penetration
rate, hydrogel polymer have been used as water retaining material in
arid and semiarid region under limitation of supplementary
irrigation sources and salinity conditions which affect negatively on
gradual growth and productivity of crops, hydrogel used to increase
a water reservoir near the root zone and increased the field capacity
of different soils, also, increased both water available for plants and
the period of its availability (Montesano et al., 2015).
• Hydrogels are also claimed to reduce fertilizer leaching, which
seems to occur through interaction of the fertilizer with the polymer,
polymer is also being considered as a potential carrier for protected
agent like pesticides and herbicides (El-Hady et al., 1981)

24. • Nutrition: Hydrogel application minimizes micronutrients from
washing out to water tables and increase water consumption
efficiency; also, they reduce the quantity of fertilization, since the
nutrient leaching is prohibited by decreasing runoff. The nutrients
are release and soil nitrification (El-Hady, 1981), increase in nutrient
absorption, osmotic moisture of soil and decrease in transplanting
stresses that cause an improvement in plant growth reaction and
increase in yield and reduction in SAP) was a water intentionally
critical condition to demonstrate the beneficial effect of the SAP.
This is particularly true considering that this experiment was carried
out in summer, inside a greenhouse; in harsh environmental
conditions (the temperature often exceeded 45 °C).
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25. 25
Case study

26. 26
Abstract:
1. The objective of this work was to evaluate the efficacy of one and two applications
of the chemical thinner Brevis® in Gala apple applied at different fruit sizes and at
different intervals between the first and second spray.
2. One or two applications with Brevis® were applied at different fruit sizes (king fruit
diameter ranging between 7.5 and 13.5 mm) and at a rate of 1.65 kg/ha for all
treatments.
3. Under the trial conditions, a Brevis® thinning effect was observed in all trials with a
reduction in crop load, fruit set and number of fruits per tree which varied according
to the number of applications.
Luis et al., 2020.

27. 27Luis et al., 2020.
All chemical application treatments resulted in a significantly lower number of fruits per
tree, fruit set and crop load in comparison with the Control, except for the single 9.5mm
application. Moreover, the double applications showed a significantly higher efficacy
than the single applications, except when one of the double applications was made at
9.5mm. Lowest reading was recorded with 7.5+13.5mm.

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1. The double applications at 7.5+11.5mm and 7.5+13.5mm resulted in
significantly lower yield in comparison with the Control.
2. No significant differences in yield (kg/tree) were observed between the
Control, and the single or double treatments in Girona and Mollerussa
2016. That is, fruit yield per tree at harvest did not show a negative
relationship with Brevis® efficacy.
Luis et al., 2020.

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In all trials, average fruit weight and fruit size increased significantly in
the treatments in which chemical thinning reduced the number of fruits
per tree. That is, average fruit weight and fruit size increased according to
the thinning effect induced by Brevis®. There were no significant
differences between the single application and the Control, except for the
treatments at 7.5 and 13.5 mm in Girona 2015. Luis et al., 2020.

30. Conclusion:
1. Fruit set varying according to the number of applications.
2. Fruit weight and diameter increased when Brevis reduced the
fruit set.
3. The degree of abscission of Brevis is highly depends of night
temperature.
4. Higher night temperatures after spraying coinciding with
greater Brevis efficacy.
5. Number of days between application was not relevant for
Brevis thinning effect.
30
Luis et al., 2020.

31. Conclusion: Food is never 100% safe. Neither is life. We must
continue to use chemicals to have a functioning society and feed a
growing population. It is important that we regulate these
chemicals to prevent misuse and abuse. It is also important that we
look for ways to use less chemicals and develop chemicals that are
less toxic.
31

32. Reference:
El-Hady, O.A, Tayel, M.Y, Lofty, A.A. 1981. Super gel as a soil
conditioner: its effect on plant growth, enzymes activity, water
use efficiency and nutrient uptake. Acta Horticulture. 119:257-265.
Luis, G, Estanis, T, Gloria, A, Joan, B, Simo, A, Joaquim, C, Begona, M,
Inmaculada, R. and Luis, A. 2020. Evaluation of chemical fruit
thinning efficiency using Brevis ® (Metamitron) on apple trees
(‘Gala’) under Spanish conditions.
Merwad, M.A., Eisa, R.A. and Saleh, M.M.S. 2016. The beneficial effect
of NAA, Zn, Ca and B on fruiting, yield and fruit quality of
Alphonso mango trees. International Journal of Chem. Tech
Research. 90: 147-157.
Montesano, F. F, Angelo, P, Pietro, S, Alessandro, S, Francesco, S. 2015.
Biodegradable Superabsorbent Hydrogel Increases Water
Retention Properties of Growing Media and Plant Growth.
Agriculture and Agricultural Science Procedia. 4:451-458.
Vijay, K, G., Bhagwan, A., Raj, K, M. and Siva, S, A. 2016. Effect of flower
enhancing plant growth regulators and fruit set improving
chemicals on flowering and fruit set of Mango (Mangifera
indica l.) Cv. Banganpalli. 7: 81-88.
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