View source for Biology:Kumquat

{{Short description|Species of small fruit-bearing tree}}
{{Automatic taxobox
|image = Kumquat from Spain.jpg
|taxon = Kumquats
}}
{{Infobox Chinese
 | pic2     = Kumquat (Chinese characters).svg
 | piccap2  = "Kumquat" in Chinese characters
 | picupright2 = 0.45
 | c        = 金橘
 | l        = "golden orange"
 | p        = jīnjú
 | w        = chin<sup>1</sup>-chü<sup>2</sup>
 | mi       = {{IPAc-cmn|j|in|1|.|j|ü|2}}
 | j        = gam<sup>1</sup>-gwat<sup>1</sup>
 | y        = gāmgwāt
 | ci       = {{IPAc-yue|g|am|1|.|gw|at|1}}
 | poj      = kim-kiat
 | kanji    = 金柑
 | romaji   = kinkan
 | hangul   = 금귤
 | hanja    = 金橘
 | rr       = geumgyul
 | tha      = ส้มจี๊ด
 | rtgs     = somchíd
 | vie      = kim quất
 | lang1    = ne
 | lang1_content = मुन्तला (muntala)
}}
'''Kumquats''' ({{IPAc-en|ˈ|k|ʌ|m|k|w|ɒ|t}} {{respell|KUM|kwot}}),<ref>{{cite web|url=http://www.collinsdictionary.com/dictionary/english/kumquat|title=Kumquat
|access-date=25 September 2014|publisher=Collins Dictionary|date=n.d.}}</ref> or '''cumquats''' in [[Social:Australian English|Australian English]], are a group of small, [[Biology:Angiosperm|angiosperm]], [[Biology:Fruit|fruit]]-bearing [[Earth:Tree|tree]]s in the family [[Biology:Rutaceae|Rutaceae]]. Their [[Taxonomy|taxonomy]] is disputed. They were previously classified as forming the now-historical genus ''Fortunella'' or placed within ''[[Biology:Citrus|Citrus]]'', {{lang|la|sensu lato}}. Different classifications have alternatively assigned them to anywhere from a single species, ''[[Biology:Citrus japonica|Citrus japonica]]'', to numerous species representing each cultivar. Recent genomic analysis defines three pure species, ''Citrus hindsii'', ''C. margarita'' and ''C. crassifolia'', with ''C.'' × ''japonica'' being a hybrid of the last two.

The edible fruit closely resembles the orange (''Citrus sinensis'') in color, texture, and anatomy, but is much smaller, being approximately the size of a large [[Biology:Olive|olive]]. The kumquat is a fairly [[Biology:Cold-hardy citrus|cold-hardy citrus]].

== Etymology ==
The English word ''kumquat'' is a borrowing of the [[Social:Cantonese|Cantonese]] {{transl|yue|gām gwāt}} ({{IPA-yue|kɐ́m kʷɐ́t̚|IPA}}; {{zh|c=金橘}}), from {{transl|yue|gām}} "golden" + {{transl|yue|gwāt}} "orange".<ref>{{cite web|url=https://www.etymonline.com/word/kumquat|title=Kumquat|publisher=Online Etymology Dictionary, Douglas Harper|date=2020|access-date=2020-06-20}}</ref>

== Description ==
Kumquat plants have thornless branches and extremely glossy leaves. They bear dainty white flowers that occur in clusters or individually inside the leaf axils. The plants can reach a height from {{convert|2.5 to 4.5|m|ft|abbr=off|frac=2}}, with dense branches, sometimes bearing small thorns.<ref name="fgcu">{{Cite web |year=2015 |title=Kumquat (Citrus japonica) |url=https://www.fgcu.edu/cas/communityimpact/foodforest/files/kumquat-ada.pdf |website=[[Organization:Florida Gulf Coast University|Florida Gulf Coast University]] |language=en |publication-place=Florida}}</ref> They bear yellowish-orange fruits that are oval or round in shape. The fruits can be {{Convert|2.5–5|cm|abbr=off|frac=2}} in diameter and have a sweet, pulpy skin and slightly acidic inner pulp. The fruit is often eaten whole by humans, and has a taste which is sweet, tart and also somewhat sour.<ref name="Experts">{{cite book |author1=Experts from Dole Food Company |url=https://books.google.com/books?id=wLf8IpZDh48C&pg=PA182 |title=Encyclopedia of Foods: A Guide to Healthy Nutrition |author2=Experts from The Mayo Clinic |author3=Experts from UCLA Center for H |publisher=Elsevier |year=2002 |isbn=9780080530871 |page=182}}</ref> Kumquat trees are self-pollinating.

== Species ==
[[Biology:Citrus taxonomy|Citrus taxonomy]] is complicated and controversial. Different systems place various types of kumquats in different species or unite them into as few as two species. Botanically, many of the varieties of kumquats are classified as their own species, rather than a cultivar.{{citation needed|date=February 2023}} Historically they were viewed as falling within the genus ''Citrus'', but the [[Biology:Citrus taxonomy#Citrus naming systems|Swingle system]] of citrus taxonomy elevated them to their own genus, ''Fortunella''. Recent phylogenetic analysis suggests they do fall within ''Citrus''. Swingle divided the kumquats into two subgenera, the ''Protocitrus'', containing the primitive Hong Kong kumquat, and ''Eufortunella'', comprising the round, oval kumquat, Meiwa kumquats,<ref name="Swingle">{{cite journal|last=Swingle| first=Walter T.| title=A new genus, Fortunella, comprising four species of kumquat oranges| journal=Journal of the Washington Academy of Sciences| volume=5| issue=5| pages=165–176| year=1915| jstor=24520657}}</ref> to which Tanaka added two others, the Malayan kumquat and the Jiangsu kumquat. Chromosomal analysis suggested that Swingle's ''Eufortunella'' represent a single 'true' species, while Tanaka's additional species were revealed to be likely hybrids of ''Fortunella'' with other ''Citrus'', so-called x''[[Biology:Citrofortunella|Citrofortunella]]''.<ref name="Yasada">{{cite journal| last1=Yasuda| first1=Kiichi| last2=Yahata |first2=Masaki |last3=Kunitake| first3=Hisato| title=Phylogeny and Classification of Kumquats (''Fortunella'' spp.) Inferred from CMA Karyotype Composition| journal=The Horticultural Journal|volume=85| number=2| pages=115–121| year=2015| doi=10.2503/hortj.MI-078| doi-access=free}}</ref>

One recent genomic analysis concluded there was only one true species of kumquat, but the analysis did not include the Hong Kong variety seen as a distinct species in all earlier analyses.<ref>{{cite journal|title=Genomics of the origin and evolution of ''Citrus'' | last1=Wu | first1=Guohong Albert | last2=Terol | first2=Javier | last3=Ibanez | first3=Victoria | last4=López-García | first4=Antonio | last5=Pérez-Román | first5=Estela | last6=Borredá | first6=Carles | last7=Domingo | first7=Concha | last8=Tadeo | first8=Francisco R | last9=Carbonell-Caballero | first9=Jose | last10=Alonso | first10=Roberto | last11=Curk | first11=Franck | last12=Du | first12=Dongliang | last13=Ollitrault | first13=Patrick | last14=Roose | first14=Mikeal L. Roose | last15=Dopazo | first15=Joaquin | last16=Gmitter Jr | first16=Frederick G. | last17=Rokhsar | first17=Daniel | last18=Talon | first18=Manuel | journal=Nature | year = 2018 | volume=554 | issue=7692 | pages=311–316 | doi=10.1038/nature25447| pmid=29414943 | bibcode=2018Natur.554..311W | doi-access=free | hdl=20.500.11939/5741 | hdl-access=free }}</ref> A 2020 review concluded that genomic data were insufficient to reach a definitive conclusion on which kumquat cultivars represented distinct species.<ref name="citrus taxonomy">{{cite book |chapter=''Citrus'' taxonomy |last1=Ollitrault |first1=Patrick |last2=Curk |first2=Franck |last3=Krueger |first3=Robert |title=The Citrus Genus |editor-last1=Talon | editor-first1=Manuel | editor-last2=Caruso |editor-first2=Marco | editor-last3=Gmitter |editor-first3=Fred G Jr. |publisher=Elsevier |year=2020 |pages=57–81 |isbn=9780128121634 |chapter-url=https://books.google.com/books?id=2wo4swEACAAJ&pg=PA57 |doi=10.1016/B978-0-12-812163-4.00004-8|s2cid=242819146 }}</ref> In 2022, a genome-level analysis of cultivated and wild varieties drew several conclusions. The authors found support for the division of kumquats into subgenera: ''Protocitrus'', for the wild Hong Kong variety, and ''Eufortunella'' for the cultivated varieties, with a divergence predating the end of the [[Earth:Quaternary glaciation|Quaternary glaciation]], perhaps between two ancestral populations isolated south and north, respectively, of the Nanling mountain range. Within the latter group, the oval, round and Meiwa kumquat each showed a level of divergence greater than between other recognized citrus species, such as between pomelo and citron, and hence each merits species-level classification. Though Swingle had speculated that the Meiwa kumquat was a hybrid of oval and round kumquats, the genomic analysis suggested instead that the round kumquat was an oval/Meiwa hybrid.<ref name="FASE">{{cite journal |last1=Zhu |first1=Chenqiao |display-authors=0 |title=New insights into the phylogeny and speciation of kumquat (''Fortunella'' ssp.) based on chloroplast SNP, nuclear SSR and whole-genome sequencing |journal=Frontiers of Agricultural Science and Engineering |year=2022 |volume=9 |issue=4 |page=627 |doi=10.15302/J-FASE-2021436|s2cid=247640336 |doi-access=free }}</ref>

{| class="wikitable"
|+Kumquat species
!'''Image'''
!'''Scientific name'''
!'''Common name'''
!'''Distribution'''
|-
|[[File:Fort-hindsii.jpg|120px]]
|''[[Biology:Citrus hindsii|Citrus hindsii]]''
|[[Place:Hong Kong|Hong Kong]] kumquat
|China
|-
|[[File:Starr-121108-0788-Fortunella_x_crassifolia-fruit-Pali_o_Waipio-Maui_(25103025561).jpg|120px]]
|''[[Biology:Citrus crassifolia|Citrus crassifolia]]''
|Meiwa kumquat
|China, Japan
|-
|[[File:Fortunella.jpg|120px]]
|''[[Biology:Citrus margarita|Citrus margarita]]''
|oval kumquat, Nagami kumquat
|Japan
|-
|[[File:Citrus_japonica.jpg|120px]]
|''[[Biology:Citrus japonica|Citrus japonica]]''
|round kumquat, Marumi kumquat, Morgani kumquat
|China, Japan
|-
|[[File:Fortunella_obovata_Fukushu_0zz.jpg|120px]]
|''[[Biology:Citrus obovata|Citrus obovata]]''
|Jiangsu kumquat, Fukushu kumquat
|China, Japan
|-
|[[File:Fortpolyandra.jpg|120px]]
|''[[Biology:Citrus swinglei|Citrus swinglei]]''
|Malayan kumquat
|[[Biology:Malay Peninsula|Malay Peninsula]]
|}

=== Hybrids ===
{{Main|Biology:Citrofortunella}}

Hybrid forms of the kumquat include the following:
* [[Biology:Calamansi|Calamansi]]: [[Biology:Mandarin orange|mandarin orange]] x kumquat<ref>{{GRIN|×''Citrofortunella microcarpa''|313479|access-date=1 June 2014}}</ref>
* Citrangequat: [[Biology:Citrange|citrange]] x kumquat
* [[Biology:Limequat|Limequat]]: [[Biology:Key lime|key lime]] x kumquat
* [[Biology:Orangequat|Orangequat]]: Satsuma mandarin x kumquat
* Procimequat: [[Biology:Limequat|limequat]] x kumquat
* Sunquat: Meyer lemon (?) x kumquat
* Yuzuquat: [[Biology:Yuzu|yuzu]] x kumquat

== Distribution and habitat ==
The kumquat plant is native to Southern {{wipe|China}}.<ref name="Purdue" /><ref>{{GRIN}}</ref> The historical reference to kumquats appears in literature of China from at least the 12th century.<ref name="fgcu" /> They have been cultivated for centuries in other parts of East Asia, South Asia, and Southeast Asia.<ref name="Experts" /> They were introduced into [[Earth:Europe|Europe]] in 1846 by [[Biography:Robert Fortune|Robert Fortune]], collector for the London Horticultural Society,<ref>{{Cite web |author= |date=29 April 2019 |title=Robert Fortune |url=https://www.royalparks.org.uk/parks/brompton-cemetery/explore-brompton-cemetery/famous-graves-and-burials/robert-fortune |access-date=19 May 2023 |work=The Royal Parks}}</ref> and are now found across the world.<ref name="Experts" />

== Cultivation ==
[[File:A lemon plant (Citrus japonica); flowering and fruiting stem Wellcome V0044760.jpg|thumb|upright|Illustration by Walter Hood Fitch|alt=Illustration, Walter Hood Fitch]]
Kumquats are much [[Earth:Hardiness (plants)|hardier]] than citrus plants such as oranges. Sowing seed in the spring is most ideal because the temperature is pleasant with more chances of rain and sunshine. This also gives the tree enough time to become well established before winter. Early spring is the best time to transplant a sapling. They do best in direct sunlight (needing 6–7 hours a day) and planted directly in the ground. Kumquats do well in USDA hardy zones 9 and 10 and can survive in temperatures as low as 18 degrees F (-7 degrees C). On trees mature enough, kumquats will form in about 90 days.

In cultivation in the {{wipe|United Kingdom}}, ''Citrus japonica'' has gained the Royal Horticultural Society’s Award of Garden Merit<ref name = RHSPF>{{cite web 
| url= https://www.rhs.org.uk/Plants/83394/i-Citrus-japonica-i-(F)/Details
| title = RHS Plantfinder - ''Citrus japonica''
| access-date=12 January 2018}}</ref> (confirmed 2017).<ref>{{cite web  | url= https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf | title = AGM Plants - Ornamental | date = July 2017 | page = 16 | publisher = Royal Horticultural Society | access-date = 24 January 2018}}</ref>

=== Propagation ===
Kumquats do not grow well from seeds and so are [[Biology:Vegetative reproduction|vegetatively propagated]] by using [[Biology:Citrus rootstock|rootstock]] of another citrus fruit,<ref name = "Purdue">{{cite web|url=http://www.hort.purdue.edu/newcrop/morton/kumquat.html|title=Kumquat, ''Fortunella'' sp. Swingle; In: Fruits of Warm Climates, Miami, FL|author=Julia F Morton|publisher=NewCROP, New Crop Resource Online Program, Center for New Crops and Plant Products, Purdue University|pages=182–185|date=1987|access-date=3 January 2020}}</ref> air layering, or [[Biology:Cutting (plant)|cuttings]].<ref name=Purdue/>

=== Varieties ===
The ''Nordmann seedless'' is a seedless cultivar of the Nagami kumquat (''[[Biology:Citrus margarita|Citrus margarita]]''). It is similar to Nagami but with a slightly different shape and lighter skin.<ref>{{cite web |title=Nordmann Seedless |url=https://citrusvariety.ucr.edu/crc4070 |access-date=9 January 2024 |website=Givaudan Citrus Variety Collection at UCR |language=en}}</ref>

The C''entennial Variegated'' is another cultivar of the Nagami kumquat. It originated from the open pollination of a Nagami kumquat tree. The fruits are striped light green and yellow when underripe, and turn orange and lose their stripes when they ripen. They are oval-shaped, necked, 2.5 inches long and have a smooth rind. They mature in winter.<ref>{{cite web |title=Kumquats / Citrus Pages |url=http://citruspages.free.fr/kumquats.php#centennial |access-date=9 January 2024 |website=citruspages.free.fr}}</ref> This [[Biology:Cultivar|cultivar]] arose [[Biology:Mutation|spontaneously]] from the oval kumquat (''[[Biology:Citrus margarita|Citrus margarita]]''). It produces a greater proportion of fruit to peel than the oval kumquat, and the fruit are rounder and sometimes necked. Fruit are distinguishable by their variegation in color, exhibiting bright green and yellow stripes,<ref name="Purdue" /> and by its lack of thorns.

The ''Puchimaru kumquat'' is a seedless or virtually seedless Japanese kumquat cultivar. It is resistant to citrus canker and citrus scab. The fruit weighs 11–20 grams and is ellipsoid in shape. It has a dark orange rind which is 4 millimeters thick. The juice content is relatively low. The oil glands are somewhat large and conspicuous. It ripens in January.<ref>{{cite web |last1=Yoshida |first1=Toshio |last2=Nesumi |first2=H. |last3=Yoshioka |first3=T. |last4=Ieki |first4=H. |last5=Ito |first5=Y. |last6=Nakano |first6=M. |last7=Ueno |first7=I. |last8=Yamada |first8=Yoshio |last9=Murase |first9=S. |date=2003 |title=New kumquat cultivar 'Puchimaru' |last10=Takishita |first10=F. |url = https://repository.naro.go.jp/record/1693/files/nifs_report_No2p9-16p.pdf|s2cid=140658196}}</ref>

== Uses ==

=== Nutrition ===
{{nutritional value
| name = Kumquats, raw<br />''Fortunella'' spp.
| image = Kumquat-0245.jpg
| kJ = 296
| protein = 1.88 g
| fat = 0.86 g
| carbs = 15.9 g
| fiber = 6.5 g
| sugars = 9.36 g
| calcium_mg = 62
| iron_mg = 0.86
| magnesium_mg = 20
| phosphorus_mg = 19
| potassium_mg = 186
| sodium_mg = 10
| zinc_mg = 0.17
| manganese_mg = 0.135
| vitC_mg = 43.9
| thiamin_mg = 0.037
| riboflavin_mg = 0.09
| niacin_mg = 0.429
| pantothenic_mg = 0.208
| vitB6_mg = 0.036
| folate_ug = 17
| choline_mg = 8.4
| vitA_ug = 15
| lutein_ug = 129
| vitE_mg = 0.15
| water = 82 g
| source_usda = 1
| note = [https://fdc.nal.usda.gov/fdc-app.html#/food-details/168154/nutrients=Full Link to USDA Database entry]
}}
A raw kumquat is 81% water, 16% [[Chemistry:Carbohydrate|carbohydrate]]s, 2% [[Biology:Protein (nutrient)|protein]], and 1% [[Chemistry:Fat|fat]] (table). In a reference amount of {{convert|100|g}}, raw kumquat supplies 71 [[Calorie|calorie]]s and is a rich source of [[Biology:Vitamin C|vitamin C]] (53% of the Daily Value), with no other micronutrients in significant content (table).

=== Essential oil ===
The [[Chemistry:Essential oil|essential oil]] of the kumquat peel contains much of the aroma of the fruit, and is composed principally of [[Chemistry:Limonene|limonene]], which makes up around 93% of the total.<ref name="KoyasakoBernhard">{{cite journal |last1=Koyasako |first1=A. |last2=Bernhard |first2=R.A. |year=1983 |title=Volatile Constituents of the Essential Oil of Kumquat |journal=Journal of Food Science |publisher=Wiley & Sons |volume=48 |issue=6 |pages=1807–1812 |doi=10.1111/j.1365-2621.1983.tb05090.x}}</ref> Besides limonene and alpha-pinene (0.34%), both of which are considered [[Chemistry:Monoterpene|monoterpene]]s, the oil is unusually rich (0.38% total) in [[Chemistry:Sesquiterpene|sesquiterpene]]s such as α-[[Chemistry:Bergamotene|bergamotene]] (0.021%), [[Chemistry:Caryophyllene|caryophyllene]] (0.18%), α-[[Chemistry:Humulene|humulene]] (0.07%) and α-muurolene (0.06%), and these contribute to the spicy and woody flavor of the fruit. Carbonyl compounds make up much of the remainder, and these are responsible for much of the distinctive flavor. These compounds include [[Chemistry:Ester|ester]]s such as isopropyl propanoate (1.8%) and terpinyl acetate (1.26%); [[Chemistry:Ketone|ketone]]s such as [[Chemistry:Carvone|carvone]] (0.175%); and a range of [[Chemistry:Aldehyde|aldehyde]]s such as [[Chemistry:Citronellal|citronellal]] (0.6%) and [[Chemistry:2-Methylundecanal|2-methylundecanal]]. Other oxygenated compounds include [[Chemistry:Nerol|nerol]] (0.22%) and Trans-lialool oxide (0.15%).<ref name="KoyasakoBernhard" />

== Gallery ==
<gallery>
File:Hoa quất.jpg|Kumquat flower
File:Quinotos.jpg|Kumquat fruit cross-section
File:Kumquat.jpg|Kumquat whole and sectioned
File:Citrus japonica1.jpg|Round kumquats (or [[Biology:Citrofortunella|citrofortunella]])
File:Starr 070111-3157 Fortunella sp..jpg|Round kumquats (or [[Biology:Citrofortunella|citrofortunella]])
File:KoumQuatLiqueur.jpg|Kumquat liqueurs from Corfu, Greece
File:Kumquat Trees (Corfu).JPG|Potted kumquat trees at a kumquat liqueur distillery in Corfu.
File:Kumquat pie.JPG|Slices of kumquat pie at the Kumquat Festival in Dade City, Florida
File:Kumquat jelly and kumquat butter.JPG|Kumquat preserves
File:Fortunella (kumquat) 9 fiore+frutto.JPG|Flowers and fruit
File:Citrus japonica3.jpg|Kumquat tree
File:Muntala.jpg|alt=Unripe Kumquat|Unripe kumquat
File:Fortunella japonica Frutigen.jpg|Ripened kumquat
File:CDC kumquat3.jpg|Kumquat
</gallery>

== See also ==
* Kumquat Festival
* Sunquat
* [[Biology:Limequat|Limequat]]
* [[Biology:Citrofortunella|Citrofortunella]]
* [[Biology:Calamansi|Calamansi]]
* Yuzuquat

== References ==
{{Reflist}}

== Further reading ==
* Burkill, I. H. (1931). "An enumeration of the species of Paramignya, Atalantia and Citrus, found in Malaya". ''Gard. Bull. Straits Settlem''. 5: 212–220.
* Mabberley, D. J. (1998). [https://web.archive.org/web/20091002183628/http://www.rbgsyd.nsw.gov.au/__data/assets/pdf_file/0003/73236/Tel7Mab333.pdf "Australian Citreae with notes on other Aurantioideae (Rutaceae)"] (PDF). ''Telopea'' 7 (4): 333–344.

== External links ==

{{Citrus}}

{{Taxonbar|from=Q5122903}}

[[Category:Citrus]]
[[Category:Fruit trees]]

{{Sourceattribution|Kumquat}}