The world of citrus fruits
Citrus plants are native to subtropical and tropical regions of Asia,
Island Southeast Asia
,
Near Oceania
, and northeastern
Australia
. Domestication of citrus species involved much hybridization and
introgression
, leaving much uncertainty about when and where domestication first happened.
[2]
A genomic, phylogenic, and biogeographical analysis by Wu
et al.
(2018) has shown that the center of origin of the genus
Citrus
is likely the southeast foothills of the
Himalayas
, in a region stretching from eastern
Assam
, northern
Myanmar
, to western
Yunnan
. It diverged from a common ancestor with
Poncirus trifoliata
. A change in climate conditions during the
Late Miocene
(11.63 to 5.33
mya
) resulted in a
sudden speciation event
. The species resulting from this event include the
citrons
(
Citrus medica
) of South Asia; the
pomelos
(
C. maxima
) of
Mainland Southeast Asia
; the
mandarins
(
C. reticulata
),
kumquats
(
C. japonica
),
mangshanyegan
(
C. mangshanensis
), and
ichang papedas
(
C. cavaleriei
) of southeastern
China
; the
kaffir limes
(
C. hystrix
) of
Island Southeast Asia
; and the
biasong
and
samuyao
(
C. micrantha
) of the
Philippines
.
[2]
[3]
Map of inferred original wild ranges of the main
Citrus
cultivars, and selected relevant wild taxa
[3]
This was later followed by the spread of citrus species into
Taiwan
and
Japan
in the
Early Pliocene
(5.33 to 3.6
mya
), resulting in the
tachibana orange
(
C. tachibana
); and beyond the
Wallace Line
into
Papua New Guinea
and
Australia
during the
Early Pleistocene
(2.5 million to 800,000 years ago), where further speciation events occurred resulting in the
Australian limes
.
[2]
[3]
The earliest introductions of citrus species by human migrations was during the
Austronesian expansion
(c. 3000–1500 BCE), where
Citrus hystrix
,
Citrus macroptera
, and
Citrus maxima
were among the
canoe plants
carried by
Austronesian
voyagers eastwards into
Micronesia
and
Polynesia
.
[6]
The citron (
Citrus medica
) was also introduced early into the Mediterranean basin from India and Southeast Asia. It was introduced via two ancient trade routes: an overland route through
Persia
, the
Levant
and the Mediterranean islands; and a maritime route through the
Arabian Peninsula
and
Ptolemaic Egypt
into
North Africa
. Although the exact date of the original introduction is unknown due to the sparseness of archaeobotanical remains, the earliest evidence are seeds recovered from the
Hala Sultan Tekke
site of
Cyprus
, dated to around 1200 BCE. Other archaeobotanical evidence include pollen from
Carthage
dating back to the 4th century BCE; and carbonized seeds from
Pompeii
dated to around the 3rd to 2nd century BCE. The earliest complete description of the citron was first attested from
Theophrastus
, c. 310 BCE.
[4]
[5]
[7]
The agronomists of
classical Rome
made many references to the cultivation of citrus fruits within the limits of their empire.
[8]
Lemons, pomelos, and sour oranges are believed to have been introduced to the Mediterranean later by Arab traders at around the 10th century CE; and sweet oranges by the
Genoese
and
Portuguese
from Asia during the 15th to 16th century. Mandarins were not introduced until the 19th century.
[4]
[5]
[7]
[8]
This group of species has reached great importance in some of the Mediterranean countries, and in the case of orange, mandarin, and lemon trees, they found here soil and climatic conditions which allow them to achieve a high level of fruit quality, even better than in the regions from where they came.
[8]
Oranges were introduced to Florida by Spanish colonists.
[9]
[10]
In cooler parts of Europe, citrus fruit was grown in
orangeries
starting in the 17th century; many were as much status symbols as functional agricultural structures.
[11]