Production of Oranges (Citrus sinensis)

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(Persian), naranja (Spanish) and the, laranja ... tends to reduce growth thus important in close space. .... citrus. PhD Thesis, Universitat Politecnica de Valencia.

Production of Oranges (Citrus sinensis) Production of fruits and vegetables June 2016 Class Presentation by Stephen Tawanda Musasa

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Presentation layout

Introduction Varieties Climatic requirements Soil requirements Propagation Culture Irrigation Pruning Harvesting Storage Common pests and diseases Uses


• Sweet orange (Citrus sinensis Osbeck L.) is a member of the citrus family (Rutaceae) and was for many years known as Citrus aurantium var. sinensis L. (Snart et al., 2006 ; García Lor, 2013) • Some of its first recorded regional names are: narang (Persian), naranja (Spanish) and the, laranja (Portuguese) • Orange tree can reach 5 m up to 15 m with rounded crown of slender branches. • The fruit is somewhat oval shaped.


Introduction • Originated in southern China, northeastern India, and southeastern Asia (Webber, 1943). • Introduced in most of the world by Italian traders after 1450 or by Portuguese navigators around 1500. • Leading producers include; USA, Brazil, Spain, Italy, India, South Africa and Egypt.

Common varieties

• Washington Navel

Originated in Brazil. Commercially grown many countries including; Brazil, Paraguay, Spain, Australia , Japan and parts of Africa

• Valencia (Late Valencia)

• Blood Oranges

Originated in China Commercially grown cultivar in California, Texas and parts of Africa. Originated in Mediterranean area Commercially grown in Egypt, Italy and Pakistan.

Climatic requirements

• Orange is subtropical crop. – Growing phase - temperatures should range from 13 -38 ˚C (Snart et al., 2006) – Dormancy phase - temperatures range from 2 - 10 ˚C (Snart et al., 2006). • Orange trees do not tolerate freezing temperatures – Temperatures below -2˚C may result to branch dieback and frozen fruit. – Young trees may be killed outright by even brief frosts. • Average precipitation varies from 13-50 cm, though oranges are frequently grown in areas receiving 100150 cm of rain.

Soil requirements

• Best soils should be well-drained deep sandy loams eg in Florida - Lakeland fine sand and often identified as high pineland soil. • Deep soils are ideal for good root development. • Shallow and water logged soils should be avoided. • Oranges do not tolerate very acidic or alkaline conditions, preferred soil pH is in the range 6–7. • Alkaline soils are not ideal because if orange trees are not properly managed chlorosis may occur. • It is important to select the appropriate rootstock for particular soil conditions.


• Orange can be grown from seed because of nucellar embryos. • Budding onto appropriate rootstocks is widely used (Snart et al., 2006). Rough lemon and sour oranges are commonly used rootstocks (Willey, 2015)


• In Brazil, Rangpur lime (C. X limonia Osbeck) has been the dominant rootstock - but rough lemon and Cleopatra mandarin are now used. – Rangpur is susceptible to Phytophthora root rot.

• Budding onto trifoliate orange (Poncirus trifoliata Raf.) - tends to reduce growth thus important in close space. – Trifoliate orange cultivar 'English Small' has successfully dwarfed 'Valencia'.

• In India, the sweet lime (C. limettioides Tanaka) was found to be the best rootstock in wet zones with high temperatures.

Merits of using rootstocks

• Assurance of cultivars of known quality • Rootstock influences the rate of growth, disease resistance, productivity, and physical and chemical attributes of the crop.

– Valencia oranges on sour orange stock have been found to have more dry matter in the peel, pulp and juice than those on rough lemon. – Washington Navel oranges on rough lemon stock have had low levels of potassium in the peel, pulp and juice; and, on 'Cleopatra mandarin' stock, even lower in the pulp and juice. – Trifoliate orange rootstock produces high levels of potassium throughout the fruit.


• Standard spacing is 7.5x7.5 m

nowadays closely-planted and hedged Weeding is essential for the first 3 years

Irrigation • Can be done to supplement rainfall. • Omitted in the fall to avoid new growth that would be damaged in winter cold spells. • Desirable in the dry season to prevent wilting. • Excessive irrigation lowers the solids content of the fruit. – Deep soils may require at most 6.25 cm of water – Shallow soils may require not more than 2.5 cm of water at a time but more frequently.

Pruning • Removal of water sprouts from young and older trees is important. • Take-out branches that are ≤30 cm to ground. • Deadwood should be cut out – cut surfaces over 2.5 cm in diameter should be sealed with pruning compound. • Orange trees that are closely - planted and hedged require mechanical pruning by special equipment.


Traditionally harvesters climbed ladders and pulled the fruits off by hand, putting them into pails or shoulder-sacks which they later emptied into field boxes. Shortage and increased cost of field labor, resulted to innovations in harvesting methods – which includes mechanical operations

Storage - life

• Oranges can be stored for 3 months at 11˚C and up to 5 months at 2 – 4˚C (Snart et al., 2006) • Deterioration in quality is primarily due to loss of moisture mostly by transpiration. – Peel becomes thinner – Reduced pulp – Later, the peel will be very thin, dry and brittle while the pulp is still juicy. • Coating the fruits with a polyethylene/wax emulsion improves the storage life.

Common pests

• Citrus rust mites – causing external blemishing and, in extreme infestations, smaller fruits, premature falling and even shedding of leaves. • Citrus red mites – common in summer, disfigure the surface of the fruit and the foliage mainly in the winter and during droughts. • Aphids cause leaves to curl and become crinkled. – Brown citrus aphid (Toxoptera citricidus) is the main vector of the tristeza virus. • Fruit flies – are a constant threat to oranges Mediterranean fruit fly, Oriental fruit fly, and African invader fruit fly

Common diseases

• Oranges are commonly affected by fungal diseases. • Greasy spot a yellow-brown, blistery, oily, brown or black on foliage – caused by Cercospora citri-grisea, • Gummosis, melanose, dieback and stem-end rot – Caused by Diaporthe citri • sweet orange scab – Caused by Elsinoe australis • Foot rot and Root rot – Caused by Phytophthora megasperma, P. palmivora and P. Parasitica (Graham et al., 2016)


• Oranges are primarily eaten fresh or consumed as juice • Commercially produced in frozen orange concentrate to be diluted with water and served as juice. • Dehydrated orange juice (orange juice powder), • Orange ‘wine’ was at one time made in Florida from fruits too affected by cold spells to be marketed. • Orange ‘wine’ is produced on a small scale in South Africa. • Orange ‘wine’ and brandy are made in Brazil from fruits which have been processed for peel oil and then crushed.


• García Lor (2013). Organization of the genetic diversity of citrus. PhD Thesis, Universitat Politecnica de Valencia • Graham J.H., Dewdney M.M., and Johnson E.G (2016) Florida citrus pest management guide: Ch.15 Phytophthora Foot rot and Root root. UF/IFAS Extension – University of Florida • Snart J., Arparaia M.l., and Harris L.J (2006) Oranges: Safe Methods to store, Preserve and Enjoy. Publication 8199 – Division of Agriculture and Natural Resources. University of Califonia • Webber H.J (1943). History and Development of Citrus Industry. [Online] • Willey D (2015). Grafting citrus trees – Bud grafting. [online] 20


Lets Enjoy Sweet Oranges!!

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