Satsuma Tangerine
Citrus
unshiu Marcovitch
Scientific
Name
Citrus unshiu Marcovitch
Common
Name
In most citrus producing areas,
satsuma mandarin is the preferred
name, but satsuma tangerine is
also used.
Family
Rutaceae
Origin
China and Japan
Distribution
Grown in cool subtropical regions
of Japan, Spain, central China,
Korea, Turkey, along the Black
Sea in Russia, southern South
Africa, South America, and on
a small scale in central California
and northern Florida. The world's
largest satsuma industry is located
in southern Japan where climatic
conditions are favorable for
the production of early ripening
satsuma tangerines of high quality.
Selection of slight mutations
and seedlings from controlled
pollinations over many years
has resulted in a collection
of over 100 cultivars that differ
in date of maturity, fruit shape,
color and quality. 'Owari' is
the primary satsuma cultivar
commercially grown in Florida
but two other cultivars, 'Silverhill'
and 'Kimbrough' are also available.
History
Satsuma mandarin may have originated
in China but it was first reported
in Japan more than 700 years
ago where it is now the major
cultivar grown. The first recorded
introduction into the United
States was in Florida by George
R. Hall in 1876. The name "satsuma" is
credited to the wife of a United
States minister to Japan, General
Van Valkenberg, who sent trees
home in 1878 from Satsuma, the
name of a former province, now
Kagoshima Prefecture, on the
southern tip of Kyushu Island,
where it is believed to have
originated. During the period
1908-1911, approximately a million
'Owari' satsuma trees were imported
from Japan and planted throughout
the lower Gulf Coast states from
the northern Florida Gulf coast
to Texas, where an extensive
tangerine industry developed.
However occasional severe freezes
have reduced the satsuma to a
cultivar of minor importance.
Importance
While this fruit is grown primarily
for fresh consumption, a portion
of the crop is canned as fruit
segments or juice in Japan, China
and Spain. In these countries
deeply colored juice is blended
with orange juice to improve
color or sold as single strength
tangerine juice. Fresh fruit
is also imported into Canada
and noncitrus producing areas
of the U.S., where it is the
earliest seasonal citrus crop
to reach the market. During the
1995-96 season, all tangerines
and tangerine hybrids were grown
on only about 6% of the total
citrus acreage in Florida, with
satsuma tangerines occupying
only a small part of that acreage.
Description
Although authorities differ as to
the number of species and appropriate
classification and grouping,
mandarins have been divided into
four groups: 1) satsuma group
(Citrus unshiu,) 2) the
King group (C. nobilis),
3) the Mediterranean group (C.
deliciosa), and 4) the common
group (C. reticulata).
Tree
Budded trees are small to medium-small,
low-growing, usually spreading and
drooping, nearly thornless, with
less foliage and a more open growth
habit than other commercial citrus
cultivars. Trees are very hardy to
cold and resistant to unfavorable
conditions but susceptible to sour
orange scab (Elsinoe fawcetti),
a fungal disease that causes scabby,
wart-like lesions on leaves, twigs
and fruit without usually affecting
internal fruit quality.
Leaves
Leaves are dark green, large, lanceolate,
tapering at the base and apex
and are typically broader than
other tangerines. Both main and
primary lateral veins are prominent
above as well as below. The petiole
is slender, very long, and has
narrow wings.
Flowers
Petals of the flower are white and
the flowers are "perfect",
containing both male and female
flower parts. Satsuma tangerine
flowers produce little viable
pollen and have few viable ovules.
However, this cultivar is highly
parthenocarpic (develops fruits
without fertilization, resulting
in the production of seedless
fruit) and does not require pollination
by other citrus cultivars.
Fruit
Botanically, the fruit of tangerines
and of all citrus species, is
a special berry known as an hesperidium.
Fruit is medium to small and
shaped like a flattened sphere;
sometimes slightly necked; seedless
(0 to 6 seeds, if any); has 10
to 12 segments that are loosely
separable; tough carpellary membranes
and a hollow axis. In areas with
cool night temperatures, the
flesh is a brilliant reddish
orange, tender and melting, with
a rich, subacid flavor. Pulp-vesicles
are short and broad. Seeds, when
present, have light green cotyledons.
Fruit Quality
Satsumas have consistently high quality
only in regions with cool winters
and hot summers. Fruit grown in humid
subtropical areas commonly matures
internally and has good eating quality
before good peel color develops.
Such internally mature but externally
green fruit is sometimes marketed
as Emerald Green satsuma tangerines.Looseness of the rind requires
that fruit be clipped at harvest to
avoid plugging or tearing, leading
to subsequent postharvest decay. Fruit
will not tolerate careless handling,
does not respond well to degreening
and in general, does not ship well.
Fruit size is also an important quality
factor. The rind is thin and somewhat
leathery; moderately smooth with large
and prominent oil glands. As fruit
matures, the rind surface becomes increasingly
bumpy and the rind separates from the
flesh somewhat.
Bearing Season
Season of maturity: November - December.
Fruit hold poorly on the tree
after maturity and must be picked
promptly, but store well.
Cold Tolerance
The satsuma tangerine tree is the
most cold- tolerant cultivar
of commercial importance. Mature
dormant trees have survived minimum
temperatures of 15°F to 18°F
in northern Florida, northern
California and southern Alabama
without serious injury. Moreover,
because of their low total heat
requirement, some cultivars ripen
earlier than oranges and most
other mandarins. As a consequence,
the satsuma tangerine is ideally
adapted to regions with winters
too cold for other citrus fruits
but with growing seasons warm
enough to produce fruit of early
maturity and good quality. Its
range of climatic adaption for
commercial culture is therefore
narrow and restricted to the
higher elevations and colder
areas of the sub-tropical zones.
In the United States, climatic
conditions suitable for satsumas
occur in central and northern
Florida, in a narrow strip extending
along the Gulf of Mexico across
Alabama, Mississippi and Louisiana
into eastern Texas and in the
Sacramento-San Joaquin Valley
basin of California. Although
these areas are subject to severe
freezes, current cold protection
methods, using in-tree microsprinklers,
can protect trees to a height
of approximately five feet. This
cold protection strategy may
be the key to at least partial
revitalization of satsuma plantings
in these areas.
October - November. Seeds: 0-6, but rarely present. As maturity passes, the neck, if present, increases in size. The rind roughens and loosens. Tree moderately vigorous but slow-growing; medium-small, spreading and drooping; very productive. Fruit of good quality which, because of the firm consistency of the flesh and tough carpellary membrances, is especially suitable for canning.
'Silverhill' Satsuma. Season of maturity: October - November. Seeds: 0-6, but rarely present. Fruit medium in size, slightly more oblate than most. Rind relatively thin and smooth. Abundant juice with high sugars and low acid content, hence very sweet. Tree very vigorous, productive and more up-right than other satsuma cultivars.'Kimbrough' Satsuma. Season of Maturity: October - November. Seeds: 0-6, but rarely present. Introduced from Louisiana, this cultivar produces larger fruit than the 'Owari' satsuma, with rind thickness, internal color, taste and fruit production comparable to 'Owari'. Trees are large and productive with a spreading growth habit and are thought to offer 1-2°F better cold tolerance than 'Owari'.
Rootstocks
for Satsuma Tangerines
Trifoliate orange is the most commonly
used rootstock for satsuma tangerines,
especially in cool climates where
maximum cold tolerance develops.
However, in Florida, where the winters
can be relatively short and interrupted
by brief periods of warm temperatures,
trifoliate orange does not provide
consistent protection from cold.
Trifoliate orange grows well on fertile,
clay to loamy type soils. It does
not develop a very deep or wide-ranging
root system and is poorly adapted
to saline or calcareous conditions,
but its resistance to foot rot, a
soil-borne disease, makes it a good
choice for soils with poor drainage.
Trifoliate orange is susceptible
to exocortis, a virus-like disease;
blight, a disease whose causal agent
is unknown; and the burrowing nematode,
with some selections resistant to
the citrus nematode. "Cleopatra" mandarin
has the highest tolerance to salinity
among commercial rootstocks, making
it a good choice in coastal areas
where ocean sprays orhigh levels
of salinity in groundwater may be
a problem. This rootstock induces
maximum cold hardiness in the scion
but is susceptible to foot rot and
highly susceptible to root rot, another
soil-borne fungal disease, especially
in poorly drained soils. Considered
a "lazy" rootstock, fruit
production may lag several years
behind that of other rootstocks.
It is susceptible to both citrus
and burrowing nematodes.
by J.J. Ferguson
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