The garden
strawberry (or simply strawberry /ˈstrɔːb(ə)ri/; Fragaria × ananassa)
is a widely grown hybrid species of the genus Fragaria (collectively known as the
strawberries). It is cultivated worldwide for its fruit. The fruit (which is
not abotanical berry, but an aggregate accessory fruit) is widely appreciated for its characteristic
aroma, bright red color, juicy texture, and sweetness. It is consumed in large
quantities, either fresh or in such prepared foods as preserves, fruit juice,pies, ice creams, milkshakes, and chocolates. Artificial strawberry flavoring is also widely used in many products
like hand sanitizers, lip gloss, perfume, and many others.
The garden strawberry
was first bred in Brittany, France, in the 1750s via a cross of Fragaria virginiana from
eastern North America and Fragaria chiloensis,
which was brought from Chile by Amédée-François
Frézier in 1714.[1] Cultivars of Fragaria× ananassa have
replaced, in commercial production, the woodland strawberry (Fragaria vesca), which was the first
strawberry species cultivated in the early 17th century.[2]
Technically, the
strawberry is an aggregate accessory fruit, meaning that the fleshy part is
derived not from the plant's ovaries but from the receptacle that holds the ovaries.[3] Each apparent "seed" (achene) on the outside of
the fruit is actually one of the ovaries of the flower, with a seed inside it.[3]
Contents
·
3 Uses
History
The first garden
strawberry was grown in France during the late 18th century.[2] Prior to this, wild strawberries and cultivated selections
from wild strawberry species were the common source of the fruit.
The strawberry fruit
was mentioned in ancient Roman literature in reference to its medicinal use.
The French began taking the strawberry from the forest to their gardens for
harvest in the 1300s. Charles V, France's king from 1364 to 1380, had 1,200
strawberry plants in his royal garden. In the early 1400s western European
monks were using the wild strawberry in their illuminated manuscripts. The strawberry
is found in Italian, Flemish, German art, and English miniatures.[citation needed]The entire strawberry
plant was used to treat depressive illnesses.
By the 1500s
references of cultivation of the strawberry became more common. People began
using it for its supposed medicinal properties and botanists began naming the
different species. In England the demand for regular strawberry farming had
increased by the mid-1500s. Instructions for growing and harvesting
strawberries showed up in writing in 1578. By the end of the 1500s three
European species had been cited; F. vesca, F. moschata,
and F. viridis. The garden strawberry was transplanted from the forests
and then the plants would be propagated asexually by cutting off the runners.
Two subspecies
of F. vesca were identified; F. sylvestris alba and F.
sylvestris semperflorens. The introduction of F. virginiana from
Eastern North America to Europe in the 1600s is an important part of history
because this species gave rise to the modern strawberry. The new species
gradually spread through the continent and did not become completely
appreciated until the end of the 18th century. When a French excursion journeyed
to Chile in 1712, it introduced the strawberry plant with female flowers that
resulted in the common strawberry that we have today.
The Mapuche and
Huilliche Indians of Chile cultivated the female strawberry species until 1551
when the Spanish came to conquer the land. In 1765, a European explorer
recorded the cultivation of F. chiloensis, the Chilean strawberry.
At first introduction to Europe, the plants grew vigorously but produced no
fruit. It was discovered in 1766 that the female plants could only be
pollinated by plants that produced large fruit; F. moschata, F.
virginiana, and F. ananassa. This is when the Europeans became
aware that plants had the ability to produce male-only or female-only flowers.
As more large-fruit producing plants were cultivated the Chilean strawberry
slowly decreased in population in Europe, except for around Brest where the
Chilean strawberry thrived. The decline of the Chilean strawberry was caused
by F. ananassa.[4]
Cultivation
Strawberry cultivars
vary widely in size, color, flavor, shape, degree of fertility, season of
ripening, liability to disease and constitution of plant.[5] Some vary in foliage, and some vary materially in the
relative development of their sexual organs. In most cases, the flowers
appear hermaphroditic in structure, but function as either
male or female.[6] For purposes of commercial production, plants are
propagated from runners and, in general, distributed as either
bare root plants or plugs. Cultivation follows one of two general
models—annual plasticulture,[7] or a perennial system of matted rows or mounds.[8] A small amount of strawberries are produced in greenhouses
during the off season.[9]
The bulk of modern
commercial production uses the plasticulture system. In this method, raised
beds are formed each year,fumigated, and covered with plastic to prevent weed growth and erosion.
Plants, usually obtained from northern nurseries, are planted through holes
punched in this covering, and irrigation tubing is run underneath. Runners are
removed from the plants as they appear, in order to encourage the plants to put
most of their energy into fruit development. At the end of the harvest season,
the plastic is removed and the plants are plowed into the ground.[7][10] Because strawberry plants more than a year or two old begin
to decline in productivity and fruit quality, this system of replacing the
plants each year allows for improved yields and denser plantings.[7][10] However, because it requires a longer growing season to
allow for establishment of the plants each year, and because of the increased
costs in terms of forming and covering the mounds and purchasing plants each
year, it is not always practical in all areas.[10]
The other major
method, which uses the same plants from year to year growing in rows or on
mounds, is most common in colder climates.[7][8] It has lower investment costs, and lower overall maintenance
requirements.[8] Yields are typically lower than in plasticulture.[8]
A third method uses a
compost sock. Plants grown in compost socks have been shown to produce
significantly higher oxygen radical absorbance capacity (ORAC),flavonoids, anthocyanins, fructose, glucose, sucrose, malic acid, and citric acid than fruit produced in the black plastic mulch or matted
row systems.[11] Similar results in an earlier 2003 study conducted by the
US Dept of Agriculture, at the Agricultural Research Service, in Beltsville
Maryland, confirms how compost plays a role in the bioactive qualities of two strawberry
cultivars.[12]
Strawberries are often
grouped according to their flowering habit.[5][13] Traditionally, this has consisted of a division between
"June-bearing" strawberries, which bear their fruit in the early
summer and "ever-bearing" strawberries, which often bear several
crops of fruit throughout the season.[13] Research published in 2001 showed that strawberries
actually occur in three basic flowering habits: short-day, long-day, and
day-neutral. These refer to the day-length sensitivity of the plant and the
type of photoperiod that induces flower formation.
Day-neutral cultivars produce flowers regardless of the photoperiod.[14]
Strawberries may also
be propagated by seed, though this is primarily a hobby activity, and is not
widely practiced commercially. A few seed-propagated cultivars have been
developed for home use, and research into growing from seed commercially is
ongoing.[15] Seeds (achenes) are acquired
either via commercial seed suppliers, or by collecting and saving them from the
fruit.
Strawberries can also
be grown indoors in strawberry pots.
Kashubian strawberry (Truskawka kaszubska or Kaszëbskô
malëna)[16] are the first Polish fruit to be given commercial
protection under EU law. They are produced in Kartuzy, Kościerzyna and Bytów counties and in the municipalities
of Przywidz, Wejherowo, Luzino, Szemud, Linia, Łęczyce and Cewice in Kashubia. Only the following varieties may be sold as kaszëbskô
malëna: Senga Sengana, Elsanta, Honeoye that have been graded as Extra or
Class I.
Manuring and harvesting
Most strawberry plants are now fed with
artificial fertilizers, both before and after harvesting, and often before
planting in plasticulture.[17]
To maintain top
quality, berries are harvested at least every other day. The berries are picked
with the caps still attached and with at least half an inch of stem left.
Strawberries need to remain on the plant to fully ripen because they do not
continue to ripen after being picked. Rotted and overripe berries are removed
to minimize insect and disease problems. The berries do not get washed until just
before consumption. They are covered in a shallow pan and refrigerated when
storing.[18]
Soil test information
and plant analysis results are used to determine fertility practices. Nitrogen
fertilizer is needed at the beginning of every planting year. There are
normally adequate levels of phosphorus and potash when fields have been
fertilized for top yields. In order to provide more organic matter a cover crop
of wheat or rye is planted in the winter the year before planting the
strawberries. Strawberries prefer a pH from 5.5 to 6.5 so lime is usually not
applied.[19]
The harvesting and
cleaning process has not changed substantially over time. The delicate
strawberries are still harvested by hand.[20] Grading and packing often occurs in the field, rather than
in a processing facility.[20] In large operations, strawberries are cleaned by means of
water streams and shaking conveyor belts.[21]
Pests
Around 200 species of
pests are known to attack strawberries both directly and indirectly.[22] These pests include slugs, moths, fruit flies, chafers, strawberry root weevils, strawberry thrips,
strawberry sap beetles, strawberry crown moth, mites, aphids, and others.[22][23] The caterpillars of a number of species of Lepidopterafeed on strawberry plants.
The strawberry
aphid, Chaetosiphon
fragaefolii, is a bug species found in the United States
(Arizona), Argentina and Chile. It is a vector of the strawberry mild yellow-edge virus.
Diseases[
See also: List of strawberry diseases
Strawberry plants can
fall victim to a number of diseases.[24] The leaves may be infected by powdery mildew, leaf spot (caused by the fungus Sphaerella fragariae),leaf blight (caused by the fungus Phomopsis obscurans),
and by a variety of slime molds.[24] The crown and roots may fall victim to red stele, verticillium wilt, black root rot, and nematodes.[24] The fruits are subject to damage from gray mold, rhizopus rot, and
leather rot.[24] To prevent root-rotting, strawberries should be planted
every four to five years in a new bed, at a different site.[25]
The plants can also
develop disease from temperature extremes during winter.[24] When watering strawberries, advice has been given to water
only the roots and not the leaves, as moisture on the leaves encourages growth
of fungus.[26]
Production trends
Although official
numbers are not available, the strawberry production of China in market year
2011/12 is estimated to be 2,100,000 tons.[28]
Domestic cultivation
Strawberries are
popular and rewarding plants to grow in the domestic environment, be it for
consumption or exhibition purposes, almost anywhere in the world. The best time
to plant is in late summer or spring. Plant in full sun or dappled shade, and
in somewhat sandy soil. The addition of manure and a balanced fertilizer aids
strong growth. Alternatively they can be planted in pots or special planters
using compost. Fibre mats placed under each plant will protect fruits from
touching the ground, and will act as a weed barrier.
Strawberries are tough
and will survive many conditions, but during fruit formation, moisture is
vital, especially if growing in containers. Moreover, protection must be
provided against slugs and snails which attack the ripe fruit. The fruit matures
in midsummer and should be picked when fully ripe — that is, the fruit is
a uniform bright red colour. The selection of different varietes can extend the
season in both directions.[29] Numerous cultivars have been selected for consumption and for exhibition
purposes. The following cultivars have gained the Royal
Horticultural Society's Award of Garden Merit:-
Propagation is by runners,
which can be pegged down to encourage them to take root,[36] or cut off and placed in a new location. Established
plants should be replaced every three years, or sooner if there are signs of
disease.
When propagating
strawberries, one should avoid using the same soil or containers that were
previously used for strawberry cultivation. After cultivating strawberries,
rotating to another culture is advisable, because diseases that attack one
species might not attack another.[37]
Uses
In addition to being
consumed fresh, strawberries can be frozen, made into preserves, as well as dried and used in prepared foods, such as cereal
bars.[38] Strawberries and strawberry flavorings are a popular
addition to dairy products, such asstrawberry-flavored milk, strawberry ice cream, strawberry milkshakes, strawberry smoothies and strawberry yogurts. Strawberries and cream is a popular
dessert, famously consumed at Wimbledon. In Sweden, strawberries are a traditional
dessert served on Midsummer Eve. Depending on area, strawberry pie, strawberry rhubarb pie, or strawberry shortcake are also popular. In Greece, strawberries are
usually sprinkled with sugar and then dipped in Metaxa, a famous brandy, and served as
a dessert. In Italy, strawberries have been used for various
desserts, especially for making strawberry tiramisu, a special form of the original tiramisu and as a popular
flavoring for gelato (gelato alla fragola).
Strawberry juice is
a fruit juice made from strawberries. Strawberry juice
or concentrate is added to cocktails, such as Minute Maid Strawberry Passion and CoolBest Strawberry
Hill.[citation needed]
Strawberry pigment extract can be used as a natural acid/base indicator due
to the different color of the conjugate acid and conjugate base of the pigment.[39]
Flavor and fragrance
As strawberry flavor
and fragrance are among the most popular hedonic characteristics for consumers,[40] they are used widely as desired features in a variety of
manufacturing, including foods, beverages, confections, perfumes and cosmetics.[41][42]
Sweetness, fragrance
and complex flavor are consistent favorable attributes of the “ideal”
strawberry experience.[43] In plant breeding and manufacturing, emphasis is placed on
sugars, acids, and volatile compounds, as these characteristics are primary sensory
factors for taste and olfaction of a ripe strawberry to elicit the greatest sensory and
hedonic responses from consumers.[44] Esters, terpenes, and furans are chemical
compounds having the strongest relationships to strawberry flavor and
fragrance, with a total of 31 volatile compounds significantly correlated to
strawberry hedonic intensity.[44]
Nutrients
One serving
(100 g; see Table) of strawberries contains approximately 33 kilocalories,
is an excellent source of vitamin C, a good source of manganese, and provides several other vitamins and dietary minerals in
lesser amounts.[45][46]
Strawberries contain a
modest amount of essential unsaturated fatty
acids in the achene (seed) oil.[46]
Few studies have
directly examined the effects of eating strawberries on human health. However,
limited research indicates that strawberry consumption may be associated with a
decreased cardiovascular disease risk and thatphytochemicals present in strawberries have anti-inflammatory or anticancer properties in laboratory studies.[47][48]
Phytochemicals
Garden strawberries
contain the dimeric ellagitannin agrimoniin which
is an isomer of sanguiin H-6.[49][50] Other polyphenols present include flavonoids, such as anthocyanins, flavanols, flavonols and phenolic acids, such ashydroxybenzoic acid and hydroxycinnamic acid.[46] Strawberries contain fisetin and possess higher levels of this
flavonoid than other fruits.[51] Although achenes comprise only about 1% of total fresh
weight of a strawberry, they contribute 11% of the fruit's total polyphenols,
which, in achenes, include ellagic acid, ellagic acid glycosides, andellagitannins.[52]
Color
Pelargonidin-3-glucoside is the major anthocyanin in strawberries
and cyanidin-3-glucoside is found in smaller proportions.
Although glucose seems to be the most common substituting sugar in strawberry
anthocyanins, rutinose, arabinose, and rhamnose conjugates have been found in
some strawberry cultivars.[46]
Purple minor pigments
consisting of dimeric anthocyanins (flavanol-anthocyanin adducts : catechin(4α→8)pelargonidin 3-O-β-glucopyranoside, epicatechin(4α→8)pelargonidin 3-O-β-glucopyranoside, afzelechin(4α→8)pelargonidin 3-O-β-glucopyranoside and epiafzelechin(4α→8)pelargonidin 3-O-β-glucopyranoside)
can also be found in strawberries.[53]
Fragrance
Chemicals present in
the fragrance of strawberries include: methyl acetate, ethyl acetate, methyl propanoate, isopropyl acetate, ethyl propanoate, methyl butyrate, (E)-2-pentenal, butyric acid, methyl isovalerate, ethyl butyrate, n-hexanal,butyl acetate, methyl pentanoate, 2-methyl butanoic acid, isopropyl butanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, (E)-2-hexenal, (E)-2-hexen-1-ol, 1-hexanol, isoamyl acetate, 2-methylbutyl acetate, 2-heptanone,propyl butyrate, ethyl pentanoate, 2-heptanol, amyl acetate, (E,E)-2,4-hexadienal, methyl hexanoate, hexanoic acid,benzaldehyde, butyl butyrate, ethyl hexanoate, (Z)-3-hexenyl acetate, hexyl acetate, (Z)-2-hexenyl acetate, isopropyl hexanoate, ethyl-2-hexenoate, d-limonene, amyl butyrate, furaneol, heptanoic acid, mesifurane, propyl hexanoate,linalool, nonanal, methyl octanoate, octanoic acid, ocimenol, benzyl acetate, ethyl benzoate, butyl hexanoate, ethyl octanoate, octyl acetate, alpha-terpineol, isoamyl
hexanoate, nonanoic acid, octyl
butyrate, ethyl decanoate, decyl
acetate, octyl
butyrate, ethyl decanoate, decyl
acetate, octyl
isovalerate, β-farnesene, γ-decalactone, α-farnesene, (E)-nerolidol, octyl hexanoate, decyl
butyrate, γ-dodecalactone.[54]
Genetics
Strawberries have
complex octaploid genetics (8 sets of chromosomes),[55] a trait favoring DNA extractions.
Strawberries have been sequenced to display 7,096 genes.[56]
Allergy
Some people experience
an anaphylactoid reaction to eating strawberries.[57] The most common form of this reaction is oral allergy syndrome, but symptoms may also mimic hay fever or include dermatitis or hives, and, in severe cases, may cause breathing
problems.[58] Proteomic studies indicate that the allergen may
be tied to a protein for the red anthocyanin biosynthesis expressed in
strawberry ripening, named Fra a1 (Fragaria allergen1).[59] Homologousproteins
are found in birch pollen and apple, suggesting that
people may develop cross-reactivity to all three species.
White-fruited
strawberry cultivars, lacking Fra a1, may be an option for
strawberry allergy sufferers. Since they lack a protein necessary for normal
ripening by anthocyanin synthesis of red pigments, they do not turn the mature
berries of other cultivars red.[59] They ripen but remain white, pale yellow or
"golden", appearing like immature berries; this also has the
advantage of making them less attractive to birds. A virtually allergen-free
cultivar named 'Sofar' is available.
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