key lime

The English word lime was derived, via Spanish then French, from the Arabic word {{lang|ar|ليمة}} līma, which is, in turn, a derivation of the Persian word limu {{lang|fa|لیمو}}.{{Cite Merriam-Webster|Lime|access-date=2017-09-23}} Key is from Florida Keys, where the fruit was naturalised. The earliest known use of the name is from 1905, where the fruit was described as "the finest on the market. It is aromatic, juicy, and highly superior to the lemon.""[http://www.oed.com/view/Entry/103132?redirectedFrom=key+lime key, n.2]". OED Online. September 2013. Oxford University Press. Accessed 24 October 2013.

File:A tree full of key limes in West Bengal, India.jpg, India]]

C. aurantiifolia is a shrubby tree, growing to {{convert|5|m|ft|abbr=off}}, 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, {{convert|2.5-9|cm||frac=2|abbr=off}} long, resembling orange leaves (the scientific name aurantiifolia referring to this resemblance to the leaves of Citrus aurantium). The flowers are {{convert|2.5|cm|in|0|abbr=on}} 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.{{cite book|author1=P. Golob|author2=Food and Agriculture Organization of the United Nations |title=The use of spices and medicinals as bioactive protectants for grains |chapter=Alphabetical List of Plant Families with Insecticidal and Fungicidal Properties |chapter-url=https://books.google.com/books?id=99B3ktmecWAC&pg=PA13 |access-date=19 June 2011 |year=1999 |publisher=Food & Agriculture Org. |isbn=978-92-5-104294-6 |pages=13–}} [https://web.archive.org/web/20021218030752/http://www.fao.org/docrep/x2230e/x2230e12.htm Webarchive mirror][http://www.hort.purdue.edu/newcrop/morton/mexican_lime.html Citrus aurantiifolia Swingle]. Hort.purdue.edu. Retrieved on 2011-06-19.

Skin contact can sometimes cause phytophotodermatitis,{{cite journal |title=Phytophotodermatitis: The other 'lime' disease |last1=Weber |first1=Ian C |last2=Davis |first2=Charles P |last3=Greeson |first3=David M |year=1999 |journal= The Journal of Emergency Medicine |volume=17 |issue=2 |pages=235–237 |issn=0736-4679 |pmid=10195477 |doi=10.1016/s0736-4679(98)00159-0}}{{cite web |url=http://www.patientcareonline.com/articles/phytophotodermatitis-fingers-young-child |title=Phytophotodermatitis on Fingers of a Young Child |date=2003-04-01 |website=Patient Care Online |language=en |access-date=2018-10-23}} which makes the skin especially sensitive to ultraviolet light.

{{See also|Citrus taxonomy}}

File:Map of inferred original wild ranges of the main Citrus cultivars, and selected relevant wild taxa (Fuller et al., 2017).png

The Key lime cultivar is a citrus hybrid, Citrus micrantha × Citrus medica (a papeda-citron cross).{{cite journal|title=Next generation haplotyping to decipher nuclear genomic interspecific admixture in Citrus species: analysis of chromosome 2 |journal=BMC Genetics |volume=15 |page=152 |year=2014 |last1=Curk |first1=Franck |last2=Ancillo |first2=Gema Ancillo |last3=Garcia-Lor |first3=Andres |last4=Luro |first4=François |last5=Perrier |first5=Xavier |last6=Jacquemoud-Collet |first6=Jean-Pierre |last7=Navarro |first7=Luis |last8=Ollitrault |first8=Patrick |doi=10.1186/s12863-014-0152-1 |pmid=25544367 |pmc=4302129 |doi-access=free }}{{GRIN |Citrus × aurantiifolia |10683 |access-date=11 December 2017}}{{cite journal |last1=Nicolosi |first1=E. |last2=Deng |first2=Z.N. |last3=Gentile |first3=A. |last4=La Malfa |first4=S. |last5=Continella |first5=G. |last6=Tribulato |first6=E. |year=2000 |title=Citrus phylogeny and genetic origin of important species as investigated by molecular markers |journal=Theoretical and Applied Genetics |volume=100 |issue=8|pages=1155–1166 |doi=10.1007/s001220051419 |s2cid=24057066}}

The 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 lime (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.{{cite journal |title=Phylogenetic origin of limes and lemons revealed by cytoplasmic and nuclear markers |last1=Curk |first1=Franck |last2=Ollitrault |first2=Frédérique |last3=Garcia-Lor |first3= Andres |last4=Luro |first4=François |last5=Navarro |first5=Luis |last6=Ollitrault |first6=Patrick |journal=Annals of Botany |volume=11 |issue=4 |pages=565–583 |year=2016 |doi=10.1093/aob/mcw005 |pmid=26944784 |pmc=4817432}}{{citation|last1=Ali |first1=Muhammad Amjad |last2=Nawaz |first2=Muhammad Azher |chapter=Advances in Lime Breeding and Genetics |title=The Lime: Botany, Production and Uses |editor-last1=Khan |editor-first1=M. Mumtaz |editor-last2=Al-Yahyai |editor-first2=Rashid |editor-last3=Al-Said |editor-first3=Fahad |year=2017 |publisher=CAB International |pages=37–53}} 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.{{cite journal|last1=Rouiss |first1=H |last2=Bakry |first2=F |last3=Froelicher |first3=Y |last4=Navarro |first4=L |last5=Aleza |first5=P |last6=Ollitrault |first6=P|title=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 |journal=Annals of Botany |volume=121 |issue=3 |pages=571–585 |year=2018 |doi=10.1093/aob/mcx179 |pmid=29293884 |pmc=5838810}}

C. aurantiifolia is native to Southeast Asia. Its apparent path of introduction was through the Middle East to North Africa, then to Sicily and Andalucia and then, via Spanish explorers, to the West Indies, including the Florida Keys. Henry Perrine is credited with introducing the Key lime to Florida.{{cite news |last=Robinson |first=T. Ralph |date=August 1942 |title=Henry Perrine: Pioneer horticulturist of Florida |volume=1 |pages=16–24 |work=Tequesta |publisher=Historical Association of Southern Florida as a Bulletin of the University of Miami |issue=2 |url=http://digitalcollections.fiu.edu/tequesta/files/1942/42_1_03.pdf |url-status=dead |access-date=28 November 2018 |archive-url=https://web.archive.org/web/20210925094544/http://digitalcollections.fiu.edu/tequesta/files/1942/42_1_03.pdf |archive-date=25 September 2021 |via=Florida International University}} From the Caribbean, lime cultivation spread to tropical and subtropical North America, including Mexico, Florida, and later California.

File:Dayap or Philippine keylime.jpg, where it is native]]

In California in the late 19th century, "Mexican" limes were more highly valued than lemons; however, in Florida, they were generally considered weeds. Then, in 1894–95, the Great Freeze destroyed the Florida lemon groves, and farmers replanted Mexican limes instead; they soon became known as the Florida Key Lime, a "beloved regional crop". But when the 1926 Miami hurricane ripped them up, they were replanted with the hardier, thornless Persian limes.Stella Parks. BraveTart: Iconic American Desserts, 2017, {{isbn|0393634272}}, p. 171-173

Since the North American Free Trade Agreement came into effect, most Key limes on the United States market have been grown in Mexico, Central America and South America. They are also grown in Texas, Florida, and California.

{{See also|Fruit tree propagation}}File:keylime-flower.jpg

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. {{Citation needed|date=May 2011}} If the plants are propagated from seed, the seeds should be stored at least 5–6 months before planting.Duke J.A., duCellier J.L. (1993): CRC handbook of alternative cash crops (page 139-145) Alternatively, vegetative propagation from cuttings or by air layering may permit fruit production within one year, and from genetically more predictable lines of plants. Another method, digging around a mature tree to sever roots, will encourage new sprouts that can be transplanted to another location. {{Citation needed|date=May 2011}} Clones are often bud grafted{{cite web|url=http://aggie-horticulture.tamu.edu/propagation/budding/budding.html|title=T or Shield Budding|work=tamu.edu|access-date=2010-04-12|archive-date=2010-03-05|archive-url=https://web.archive.org/web/20100305092048/http://aggie-horticulture.tamu.edu/propagation/budding/budding.html|url-status=dead}} into rough lemon or bitter orange to obtain strong root stocks.

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,{{cite web|url=http://www.hort.purdue.edu/newcrop/morton/mexican_lime.html|title=Mexican Lime|year= 1987|pages= 168–172|work= Fruits of warm climates|first=Julia F.|last=Morton|publisher=Purdue}}{{cite web|url=http://aggie-horticulture.tamu.edu/citrus/limes.htm|title=Home Fruit Production|work=tamu.edu}} 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.

File:KeyLime 2010 07 25 0001.jpg

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.

File:Starr 080610-8303 Citrus aurantiifolia.jpg]]

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 {{convert|12.5|and(-)|15.5|°C|0|abbr=on}} 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 {{convert|9|-|10|°C|abbr=on}} 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.Bisen A., Pandey S.K., Patel N.: Effect of skin coatings on prolonging shelf life of kagzi lime fruits (Citrus aurantiifolia Swingle). Journal of Food Science and Technology (2012) 49(6).753-759. (page 139–145)

Key limes are made into black lime by boiling them in brine and drying them. 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.

The annual Key Lime Festival in Key West, Florida, has been held every year since 2002 over the Independence Day weekend and is a celebration of Key limes in food, drinks, and culture, with a significant emphasis on Key lime pie.{{cite web |url=http://keylimefestival.com/home.htm |title=Key Lime Festival of the Florida Keys |website=KeyLimeFestival.com }}

{{Reflist}}

• {{Wikispecies-inline|Citrus aurantiifolia}}
• {{Commons category-inline|Citrus × aurantiifolia}}
• [http://citeseerx.ist.psu.edu/viewdoc/download?rep=rep1&type=pdf&doi=10.1.1.214.5466 Citrus aurantiifolia (Christm.) Swingle] United States Forest Service description
• [http://lemoncitrustree.com/store/key-lime-tree-history Key Lime Tree History]
• [https://www.nature.com/articles/srep04853 Characterization of limes (Citrus aurantifolia) grown in Bhutan and Indonesia using high-throughput sequencing]

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Category:Citrus

Category:Citrus hybrids

Category:Fruit trees

Category:Limes (fruit)