Key lime (
Citrus × aurantiifolia) is a citrus hybrid (C.
micrantha x C. medica) with a spherical fruit, 2.5–5 cm
(0.98–1.97 in) in diameter, that is yellow when ripe but
usually picked green commercially.
It is smaller and seedier, with a higher acidity, a stronger aroma,
and a thinner rind, than that of the
Persian lime (
latifolia). It is valued for its unique flavor compared to other
limes. The name is derived from its association with the
where it is best known as the flavoring ingredient in
Key lime pie. It
is also known as West Indian lime, bartender’s lime, Omani lime, or
Mexican lime, the last classified as a distinct race with a thicker
skin and darker green color. Philippine varieties have various names,
including dayap and bilolo.
4.1 Cultivation and propagation
4.3 Postharvest process
6 External links
The English word "lime" was derived, via Spanish then French, from the
Arabic word ليمة līma (Persian: لیمو limu). "Key" is
Florida Keys, where the fruit is naturalized. The Oxford English
Dictionary dates the first use of "key lime" to 1905, in an issue of
Country Gentleman, which described the fruit as "the finest on the
market. It is aromatic, juicy, and highly superior to the lemon."
C. aurantiifolia is a shrubby tree, to 5 m (16 ft), with
many thorns. Dwarf varieties exist that can be grown indoors during
winter months and in colder climates. Its trunk, which rarely grows
straight, has many branches, and they often originate quite far down
on the trunk. The leaves are ovate, 2.5–9 cm
(1–3 1⁄2 in) long, resembling orange leaves (the
scientific name aurantiifolia refers to this resemblance to the leaves
of the orange,
Citrus aurantium). The flowers are 2.5 cm
(1 in) in diameter, are yellowish white with a light purple tinge
on the margins. Flowers and fruit appear throughout the year, but are
most abundant from May to September in the Northern Hemisphere.
When in contact with the skin, the
Key lime can sometimes cause
phytophotodermatitis, in which a chemical reaction makes the skin
extra sensitive to ultraviolet light.
This particular cultivar is a citrus hybrid,
Citrus micrantha ×
Citrus medica (a papeda-citron cross).
C. aurantiifolia is native to Southeast Asia. Its apparent path of
introduction was through the
Middle East to North Africa, then to
Andalucia and via Spanish explorers to the West Indies,
Florida Keys. From the Caribbean, lime cultivation
spread to tropical and subtropical North America, including Mexico,
Florida, and later California.
North American Free Trade Agreement
North American Free Trade Agreement came into effect, many
Key limes on the US market are grown in Mexico,
Central America and
South America. They are also grown in Texas, Florida, and California.
Key lime has given rise to several other lime varieties. The best
known, the triploid progeny of a Key lime-lemon cross, is the Persian
Citrus × latifolia), the most widely-produced lime, globally.
Others are, like their parent, classed within C. aurantiifolia.
Backcrossing with citron has produced a distinct group of triploid
limes that are also of commercial value to a limited degree, the seedy
Tanepeo, Coppenrath, Ambilobe and Mohtasseb lime varieties as well as
the Madagascar lemon. Hybridization with a mandarin-pomelo cross
similar to the oranges has produced the Kirk lime. The New Caledonia
and Kaghzi limes appear to have resulted from an F2 Key lime
self-pollination, while a spontaneous genomic duplication gave us the
tetraploid Giant Key lime. The potential to produce a wider
variety of lime hybrids from the
Key lime due to its tendency to form
diploid gametes may reduce the disease risk presented by the limited
diversity of the current commercial limes.
Cultivation and propagation
Flowers of the
Key lime plant
There are various approaches to the cultivation of Key limes. This
variety of citrus can be propagated from seed and will grow true to
the parent. The seeds must be kept moist until they can be planted, as
they will not germinate if allowed to dry out. If the
plants are propagated from seed, the seeds should be stored at least
5–6 months before planting. Alternatively, vegetative
propagation from cuttings or by air layering may permit fruit
production within one year, and from genetically more predictable
lines of plants. Or digging around a mature tree to sever roots will
encourage new sprouts that can be transplanted to another
location. Clones are often bud grafted into rough
lemon or sour orange to obtain strong root stocks (see also fruit tree
It is often advisable to graft the plants onto rootstocks with low
susceptibility to gummosis, because seedlings generally are highly
vulnerable to the disease. Useful rootstocks include wild grapefruit,
cleopatra mandarin and tahiti limes. C. macrophylla is also
sometimes used as a rootstock in
Florida to add vigor.
Climatic conditions and fruit maturation are crucial in cultivation of
the lime tree. Under consistently warm conditions potted trees can be
planted at any season, whereas in cooler temperate regions it is best
to wait for the late winter or early spring. The
Key lime tree does
best in sunny sites, well-drained soils, good air circulation,
and protection from cold wind. Because its root system is shallow, the
Key lime is planted in trenches or into prepared and broken rocky soil
to give the roots a better anchorage and improve the trees' wind
resistance. Pruning and topping should be planned to maximise the
circulation of air and provide plenty of sunlight. This keeps the
crown healthily dry, improves accessibility for harvesting, and
discourages the organisms that cause gummosis.
White key lime flower in different stages.
The method of cultivation greatly affects the size and quality of the
harvest. Trees cultivated from seedlings take 4–8 years before
producing a harvest. They attain their maximal yield at about 10 years
of age. Trees produced from cuttings and air layering bear fruit much
sooner, sometimes producing fruit (though not a serious harvest) a
year after planting. It takes approximately 9 months from the blossom
to the fruit. When the fruit have grown to harvesting size and begin
to turn yellow they are picked and not clipped. To achieve produce of
the highest market value, it is important not to pick the fruit too
early in the morning; the turgor is high then, and handling turgid
fruit releases the peel oils and may cause spoilage.
3 key lime fruits with persistent styles.
Shelf life of Key limes is an important consideration in marketing.
The lime still ripens for a considerable time after harvesting, and it
is usually stored between 12.5 and 15.5 °C (55–60 °F) at
a relative humidity of 75–85%.
Special procedures are employed to
control the shelf life – for example, applications of growth
regulators, fruit wax, fungicides, precise cooling, calcium compounds,
silver nitrate, and special packing material. The preferred storage
conditions are temperatures of 9–10 °C (48–50 °F) and
a humidity over 85%, but even in ideal conditions post-harvesting
losses are high.
In India most
Key lime producers are small scale farmers without
access to such post-harvesting facilities, but makeshift expedients
can be of value. One successful procedure is a coating of coconut oil
that improves shelf life, thereby achieving a constant market supply
of Key limes.
Key limes are made into black lime by boiling them in brine and drying
Black lime is a condiment commonly used in the Middle East.
The yield varies depending on the age of the trees. Five- to
seven-year-old orchards may yield about 6 t/ha (2.7 tons/acre), with
harvests increasing progressively until they stabilise at about
12–18 t/ha (5.4–8 tons/acre). Seedling trees take longer to attain
their maximal harvest, but eventually out-yield grafted trees.
^ "Dayap /
Citrus aurantifolia / LIME: Philippine Medicinal Herbs /
Philippine Alternative Medicine". Stuartxchange.org. Retrieved
Merriam-Webster Dictionary. Retrieved 2017-09-23.
^ "key, n.2". OED Online. September 2013. Oxford University Press.
Accessed 24 October 2013.
^ P. Golob; Food and Agriculture Organization of the United Nations
(1999). "Alphabetical List of Plant Families with Insecticidal and
Fungicidal Properties". The use of spices and medicinals as bioactive
protectants for grains. Food & Agriculture Org. pp. 13–.
ISBN 978-92-5-104294-6. Retrieved 19 June 2011. Webarchive
Citrus aurantiifolia Swingle. Hort.purdue.edu. Retrieved on
^ Weber, I. C.; Davis, C. P.; Greeson, D. M. (1999-03-01).
"Phytophotodermatitis: the other "lime" disease". The Journal of
Emergency Medicine. 17 (2): 235–237.
doi:10.1016/s0736-4679(98)00159-0. ISSN 0736-4679.
Phytophotodermatitis on Fingers of a Young Child Patient Care
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^ Curk, Franck; Ancillo, Gema Ancillo; Garcia-Lor, Andres; Luro,
François; Perrier, Xavier; Jacquemoud-Collet, Jean-Pierre; Navarro,
Luis; Ollitrault, Patrick (2014). "Next generation haplotyping to
decipher nuclear genomic interspecific admixture in
analysis of chromosome 2". BMC Genetics. 15: 152.
Citrus × aurantiifolia". Germplasm Resources Information Network
Agricultural Research Service
Agricultural Research Service (ARS), United States Department
of Agriculture (USDA). Retrieved 11 December 2017.
^ Nicolosi, E.; Deng, Z.N.; Gentile, A.; La Malfa, S.; Continella, G.;
Tribulato, E. (2000). "
Citrus phylogeny and genetic origin of
important species as investigated by molecular markers". Theoretical
and Applied Genetics. 100 (8): 1155–1166.
^ Curk, Franck; Ollitrault, Frédérique; Garcia-Lor, Andres; Luro,
François; Navarro, Luis; Ollitrault, Patrick (2016). "Phylogenetic
origin of limes and lemons revealed by cytoplasmic and nuclear
markers". Annals of Botany. 11: 565–583.
^ Ali, Muhammad Amjad; Nawaz, Muhammad Azher (2017), "Advances in Lime
Breeding and Genetics", in Khan, M. Mumtaz; Al-Yahyai, Rashid;
Al-Said, Fahad, The lime: botany, production and uses, CAB
International, pp. 37–53
^ Rouiss, H; Bakry, F; Froelicher, Y; Navarro, L; Aleza, P;
Ollitrault, P (2018). "Origin of C. latifolia and C. aurantiifolia
triploid limes: the preferential disomic inheritance of
doubled-diploid 'Mexican' lime is consistent with an interploid
hybridization hypothesis". Annals of Botany. 121: 571–585.
^ a b c d e Duke J.A., duCellier J.L. (1993): CRC handbook of
alternative cash crops (page 139-145)
^ "T or Shield Budding". tamu.edu.
^ Morton, Julia F. (1987). "Mexican Lime". Fruits of warm climates.
Purdue. pp. 168–172.
^ "Home Fruit Production". tamu.edu.
^ Bisen A., Pandey S.K., Patel N.: Effect of skin coatings on
prolonging shelf life of kagzi lime fruits (
Swingle). Journal of Food Science Technology (2012) 49(6).753-759.
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