This document provides information on citrus fruits. It discusses the botanical classification of citrus, important citrus growing states in India, common varieties like oranges and limes. It also outlines cultivation practices including soil and climate requirements, propagation, irrigation, fertilizer use, pest and disease management. Harvesting, post-harvest handling techniques like cleaning, grading, waxing and storage are described. It identifies common post-harvest diseases and losses.

1. SUBMITTED TO: SUBMITTED BY:
DR. T.S. BISHT ANSHIKA SINGH
B.Sc. Horticulture
VI Sem.

3.  Common Name: Citrus
 Botanical name: Citrus spp.
 Family: Rutaceae
 Chromosome no: 2n=18
 Type of fruit: Hesperidium
 Edible Part: Juicy Placenta
 Origin: China- Sweet orange, Mandarin
India- Kagzi lime
 Citrus growing states in India: Andhra Pradesh,
Maharashtra, Punjab, Madhya Pradesh, Gujarat,
Rajasthan, Karnataka, Odisha, Bihar, Assam

4. 1. Mandarin group:
 Citrus reticulata
 C. unshu
 C. deliciosa
 C. nobilis
2. Orange group:
 C. sinensis
 C. aurantium
3. Grape fruit group:Pummelo
 C. grandis
 C. paradisi
4. Acid group:Lime
 C. limon
 C. jambheri
 C. aurantifolia
 C. medica
 C. karna
 C. limonica

5.  Grows well in sub-tropical climates producing
good quality fruits and cannot tolerate severe
frosts.
 It can tolerate occasional light frosts. Optimum
temperature range is 16-20℃ within a range of
17-40℃. Annual rainfall of 500-775 mm is
optimum.
 Citrus (except lemons) require shorter days and
cooler temperature in winter for a normal
production rhythm.
 Sweet orange can be grown in any well drained
soils, sandy or clay loams are preferable.

6.  The bearing tree should be given the
fertilizer dose at the ratio of 550 gm: 370
gm: 550 gm NPK/plant/year, depending upon
its performance and FYM @ 25-30 kg/plant/
year is preferred.
 Graded dose of fertilizers can be applied
from 1st year to 10th year.
 Fertilizers should be applied in a ring 30-40
cm wide just below the canopy of the tree at
a distance of at least 1-2 m from the trunk.

7.  Propagation is still practised in the case of
acid limes and to produce rootstocks.
 In India, citrus trees are propagated both by
seeds and vegetative means.
 Seed budding purposes. It produces true-to-
type seedlings.
 Shield or T budding is the most commonly
used method of vegetative propagation.
 Budding is generally done either in spring or
in September.

8.  • Irrigation requirements depend upon soil and
weather conditions.
 • Irrigations should be regular during fruit
development.
 • Water should never come in direct contact
with the trunk of the tree; For this reason
double ring or check bund method is best suited
for this crop.
 • Presently drip irrigation is becoming popular
which helps in saving of irrigation water.
 • Stopping irrigation 1 or 2 months prior to
flowering is beneficial to the crop, till the tree
withers and drops half of its leaves.

9.  • During the pre-bearing stage of the plants,
vegetables other than solanaceous crops can be
grown, taking care not to waterlog the soil
around the trunks of the plants.
 • Leguminous crops are the best Intercropping
with ‘pea’ was found to improve the yield of
sweet orange. Cucurbits also can be grown
successfully.
 • Weeds can be controlled with pre-emergence
spray of diuron @ 3 Kg/ha twice at 120 days
intervals.
 • Other weedicides used are simazine, atrazine,
bromacil, 2, 4-D. etc.

10.  • No regular pruning except removing dead,
diseased and over crowding branches after
harvesting of the fruit.
 • Plants should be trained during first 3 years
to have a well distributed frame work at 1m
height on a single trunk.

11.  Sweet orange takes 9-12 months for
maturity. Being non-climacteric should be
harvested only after full maturity of the
fruits. Harvesting seasons are Dec-Feb in
North India, Oct-march in South India, Nov-
Jan (Ambe bahar), March-May (Mrig bahar) in
central and western India.
 Yield varies from 500-2000 fruits/tree
depending upon the variety, agro-climatic
conditions and age of the tree.

12. MAJOR CAUSES OF POST HARVEST LOSSES OF
CITRUS:
 Lack of maintenance of orchards
 Faulty harvesting methods
 Miss handling of the produces
 Mould growth and rotting
 Shriveling and weight loss
 Loss of firmness
 Improper means of distribution
 Improper storage facilities

13.  Farmer’s field(15-20%)
 Packaging(15-20%)
 Transportation(30-40%)
 Marketing (30-40%)

14. S.NO. INDICES VALUES
1. Rind colour Yellow- orange, orange
2. Juice yield >49.00%
3. Days from flowering to harvesting 230-250
4. TSS(°Brix) 9.5-10.00
5. Titratable acidity (%) 0.75-0.81
6. TSS: Acid ratio 12.38-12.97

15.  Fruit should be harvested using a pair of clippers
or by carefully twisting and pulling the fruit from
the tree so the button remains attached to the
fruit.
 Stems left on the fruit should be cut off because
they can puncture other fruit, causing post
harvest decay and fruit spoilage.
 Harvested fruit should be carefully put into
padded field crates, well ventilated plastic
containers, or picking bags.
 Picking bags either strapped around the waist or
put over the shoulder and made with a quick-
opening bottom.

17.  Cleaning
 Fruit can be cleaned manually by hand rubbing
individual fruit dumped in a tank of sanitized water.
 The wash water should be sanitized with 150 ppm
hypochlorous acid (household bleach) maintained at a
pH of 6.5.
 Fruit can also be cleaned mechanically by passing the
citrus fruit over a series of roller brushes wetted
from above with spray nozzles.
 Benomyl( 500 ppm) or thiabendazole (1000 ppm) are
the most effective post harvest fungicides and can be
applied as high- pressure sprays after washing.
 These fungicides can also be applied in water-
emulsion wax at double the concentration.

18.  Grading
 The fruit are inspected and unripe,
immature, undersized, damaged or decayed
fruits are discarded. For local markets, the
citrus fruits are graded as per the size into
small, medium and large grades. The
differences between categories will depend
on the type of fruit.

19.  For exports of Nagpur mandarins, the various
grades recommended are as follows –
GRADE SIZE(mm) NO. OF FRUITS/ 10 KG PACKING
50-55 115
55-60 98
60-65 84
65-70 76
70-75 64

20.  Waxing:
 Most of the natural wax on the peel surface is
removed during washing.
 Waxing the fruit will add shine to the surface,
reduce moisture loss, and extend market life.
 Wax can applied by manually rubbing it onto the
fruit surface or by spraying/ dripping it on a bed
of slowly rotating horsehair- grade brushes.
 Water-emulsion waxes do not require a
completely dry fruit surface. Orange waxes are
carnauba or shellac based.

21. Decay loss(%) due to mould growth
TREATMENTS DAYS AFTER STORAGE
7 11 20 30
Carbendazim
(0.1%)
Nil Nil 6.30 11.42
Control 11.45 33.13 48.00 62.11

22.  Packaging
 Citrus fruits are packed in sacks, bags, bamboo
baskets and wooden boxes for sending to local
markets. For urban markets, citrus fruits are packed
in telescopic cardboard boxes. Corrugated trays are
equally effective as packaging material while
transporting the fruits. Use of such trays is cost
effective due to its reusability. For export of Nagpur
mandarin, usually 2 piece, telescopic, corrugated
fibreboard boxes of three ply or five ply should be
used. The size of the box may vary according to the
requirement of the importing country. Normally a box
size of 49.5 x 29.5 x 17.5 cm having 10 kg capacity is
recommended. The boxes must have 5% area punched
as holes for ventilation. To immobilize the movement
of fruits inside the box, three ply wax treated
dividers having ventilation holes are used.

23.  De- Greening
 Citrus fruit can be treated with ethylene to de-
green the skin to improve external peel colour.
 Important for the export market.
 Ethylene treatment is solely cosmetic and does
not alter the flavor of the fruit.
 The de- greening process involves exposing green
skinned orange fruit to low levels of ethylene (
usually between 1 ppm to 10 ppm) at 20°C to
25°C, 90% RH for several days.
 Good internal air movement is needed so that
the air circulates every 2 to 3 minutes.
 The CO2 levels inside the treatment chamber
should not rise above 2000 ppm.

24.  Storage
 After the fruits are harvested, they should be
treated with wax to reduce post harvest
damage. Treatment of fruits with Bavistin (1000
ppm) can reduce post harvest losses and extend
the shelf life to 25-26 days even at room
temperature. Shelf life of Nagpur mandarin can
be extended by three weeks on wrapping the
fruits with heat shrinkable polythene and
Cryovate film (D 955 and BDF 2001). O The ideal
storage temperatures for Nagpur mandarin is 6-7
C at 85-90% relative humidity while O lime &
lemon are stored at 10-12 C with 90-95% relative
humidity.

25.  Transport
 Citrus fruits are transported by rail or road
as ordinary cargo and without refrigeration,
which often leads to heavy loss due to decay
and fungal infections.

26.  Cool Chain
 Cool chain is essential during the transport of export
quality commodity all the way from the farm to the
customer. This helps in maintaining the temperature inside
the box at the same low level as in the cold storage. The
various stages of the cool chain are :
 Coldstore at the farm.
 Refrigerated truck from farm to the airport
 Coldstore at the airport.
 Building up of the pallet in a coldstore at the airport.
 Loading the aircrafts directly from the coldstore in a short
time.
 Cargo aircraft maintains coldstore temperature in hold.
 Off loading direct into a coldstore in the receiving country.
 Refrigerated truck to the customers.

27.  Green mould:
 Green mould is generally the worst post harvest disease of citrus.
 The initial symptom appears as a soft, watery, slightly discoloured spot on the
rind.
 After the spot enlarges to a diameter of about 2.5 cm, olive green spores are
produced inside a zone of white fungal growth and softened rind tissue.
 Blue mould:
 Blue mould decay and symptoms are similar to green mould, except the fungal
spores are blue in colour.
 Blue mould grows better than green mould below 10°C.
 Unlike green mould, blue mould spreads in packed containers.
 Stem- end rot:
 Stem- end rot is caused by several different fungal species and symptoms vary.
 Decay begins as water- soaked spots at the stem end of the fruit that turn brown
and continue to spread down the rind.
 Infected tissue shrinks and a clear line of separation is formed between the
diseased and healthy rind (Phomopsis), or unevenly, producing finger like
projections of brown tissue (Diplodia). Stem-end rot can be retarded by post
harvest applications of 2,4- dichlorophenoxy acetic acid (500 ppm), which slow
button maturity.

28. 1. Green mould 2. Stem end rot

29.  Oleocellosis (Oil Spotting):
 Oil spotting results from damage to the peel that ruptures the
oil glands.
 Extruded oil kills the rind cells, causing them to turn brown
and form spots on the fruit surface.
 Harvesting in the early morning or while dew is on the fruit
should be avoided.
 Oil spotting can be reduced by picking fruit when the surface is
completely dry, waiting to pick 2 or 3 days after a rain, using
foam lined or padded field containers, and having pickers wear
cotton gloves.
 Stem-end Rind Breakdown (SERB):
 SERB is a collapse and subsequent darkening of the rind around
the stem end of oranges.
 A narrow band of rind around the stem usually remains
undamaged. The collapse of tissue is due to excessive moisture
loss from the rind.
 The incidence of SERB is reduced by irrigating prior to harvest
during dry weather and waxing the fruit.

30. 1. Oleocellosis 2. Stem end rind breakdown

31.  https://ecourseonline.iasri.res.in
 https://www.slideshare.net/pawannagar8/ci
trus-ppt
 https://www.slideshare.net/manzarhussain0
07/post-harvest-handling-of-citrus-fruit-in-
north-east-india
 Google images