• Degreening of citrus fruit is done by CaC₂ (Calcium Carbide)
• Best time of pruning – Late winter or early spring
• Deficiency of zinc along with N₂ is the major nutritional problem of sweet orange
• Pineapple and Valencia – an indicator of greening
• Sweet orange is highly polyembryonic (varies from 40 to 95%)

Varieties

1. Hamlin – early variety
2. Jaffa – Midseason variety
3. Pineapple – mid-season variety
4. Valencia – Late-season variety

   

5. Mosambi – Most popular in MH, Best Rootstock – Rangpur lime
6. Satgudi – Popular in AP, Best Rootstock – Rough Lemon
7. Blood Red – Popular in North India Best Rootstock – karna khatta, Jatti khatti
8. Shamuti – Seedless variety
9. Washinghton Neval
10. Batavin
11. Mudkhed – Bud mutant of Nagpur mandarin

Climate

• Sweet orange requires dry and semi-arid conditions coupled with distinct summer and winter season with low annual precipitation
• Low humidity and severe winter result in good colour development and external appearance in fruits
• High humidity favours thin skin and plentiful juice
• Strong winds, weather hot or cool are injurious

Soil

• Medium to light loamy soils rich in organic matter, well-drained having a pH range from 6 to 8 are suitable

Propagation

• Commercially propagated by Budding (patch, forkart, or Budding)
• The best time of budding is when the plant has good sap flow and the cambium tissue is highly active.

Planting

• The pits are dug 60cm³ size in summer and filled up with 20-30 kg well rotten farmyard manure and good soil.
• The distance of planting maybe 4×4 or 5×5 m.
• Planting is done at the beginning of the monsoon. Where rainfall is light.
• Whereas in areas of heavy rainfall, it is done at the end of the monsoon.

Manure and fertilizers

• N P K 290:200:240gm/tree / year at 10^th
• FYM 100kg/tree
• North India Manuring is winter (Rec.-January) & second dose applied in April – May
• Western and southern India manuring is done before the onset of monsoon and sometimes second application also given in December or early January.

Irrigation

• During summers irrigation short interval of 7 days is needed. However, in winter 12-15 days

Interculture and intercropping

• Shallow cultivation at 3-4 months interval keeps down the weed
• Sweet orange plantation can be intercropped with leguminous crops like berseem, lucerne.

Training and pruning

• The young plant should be given support if needed so that they do not bend
• Sprouts arising below bud union and water sprouts should be removed
• Do not prune the tree except unwanted disease twigs are cut and removed out of the field

Bahar treatment

• Under western and southern parts of India, growers like to have Mrig bahar crop, because this helps them to ride over the water scarcity in the months of April and May
• It is done by withholding water 60 days in advance of the normal flowering season and about 30 days prior to flowering season roots are exposed by soil removing soil around the tree trunk. The depth of soil removes is about 10-15cm or so. After about 6-10days of exposure, soil is back filled along with 20-25kg of FYM followed by light irrigation
• In North India flowering normally once a year in the spring season (Feb-March)

Fruit drop

• Pre harvest fruit drop common problem
• Mosambi and Red blood are more prone to fruit drop
• Valencia late is less prone to fruit drop
• Reason for fruit drop

Physiological fruit drop: 

• Formation of abscission layer to stem point
• Imbalance of growth regulators such as auxins, cytokinin gibberellins, etc.
• Excess or deficiency of certain essential nutrients.
• Unfavorable weather condition
• Cultural practices

Control measures

• Spray 2, 4-D (20ppm) in the month of August
• Apply recommended doses of nutrients
• Follow improved cultural practices at right time with the right way

Pathological fruit drop

• Alternaria citri and colletrotrichum gleosporiodes
• Following fungus attack on styler end of the fruit causes styler end rot

Control Measures

• Spray with copper fungicide during fruit setting (August) and repeat it at a 3-week intervals.

Harvesting

• Fruits are harvested when the rind colour change from dark green to light green to yellowish colour.
• Other criteria are TSS/acid ratio.
• The fruits of sweet orange mature in 9-13 months
• In North, India harvesting is done in the month of Dec. to Feb.
• South India Fruits harvesting October to March.
• In Central India November-January.

Yield

1000 to 1500 Fruits / tree/ Year

Storage

Ideal storage temperature and relative humidities are 6.0-6.5⁰ C and 85-90% respectively which gives about 15-18 weeks of storage life.