Wednesday, April 21, 2010

Garden strawberry


The garden strawberry is a common plant of the genus Fragaria which is cultivated worldwide for its fruit, the (common) strawberry. The fruit is widely appreciated, mainly for its characteristic aroma but also for its bright red color, and it is consumed in large quantities—either fresh, or in prepared foods such as preserves, fruit juice, pies, ice creams, milk shake, etc. Artificial strawberry aroma is also widely used in all sorts of industrialized food products.

The garden strawberry was first bred in Brittany, France in 1740 via a cross of Fragaria virginiana from eastern North America , which was noted for its flavor, and Fragaria chiloensis from Chile and Argentina brought by Amédée-François Frézier, which was noted for its large size.

Cultivars of Fragaria × ananassa have replaced, in commercial production, the woodland strawberry, which was the first strawberry species cultivated in the early 17th century.

The strawberry is technically an accessory fruit, meaning that the fleshy part is derived not from the plant's ovaries (achenes) but from the receptacle that holds the ovaries.Accessory fruits were sometimes in the past referred to as "false" or "spurious" fruits, but those terms have been criticized as "inapt" and are not used by botanists today

Cultivation
Closeup of a healthy, red strawberry

Strawberry cultivars vary remarkably in size, color, flavor, shape, degree of fertility, season of ripening, liability to disease and constitution of plant. 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.

For purposes of commercial production, plants are propagated from runners and generally distributed as either bare root plants or plugs. Cultivation follows one of two general models, annual plasticulture or a perennial system of matted rows or mounds.A small amount of strawberries are also produced in greenhouses during the off season.
A large strawberry field with plastic covering the earth around the strawberry plants.
A garden using the plasticulture method

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, 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.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. 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.

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. It has lower investment costs, and lower overall maintenance requirements.Yields are typically lower than in plasticulture.

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.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.
A closeup view of hundreds of red strawberries.
Fragaria × ananassa 'Chandler,' a short-day commercial cultivar grown in California

Strawberries are often grouped according to their flowering habit.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.More recently, research has shown 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 which induces flower formation. Day neutral cultivars produce flowers regardless of the photoperiod.

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. Seeds (achenes) are acquired either via commercial seed suppliers, or by collecting and saving them from the fruit.


Most strawberry plants are now fed with artificial fertilizers, both before and after harvesting, and often before planting in plasticulture.

The harvesting and cleaning process has not changed substantially over time. The delicate strawberries are still harvested by hand. Grading and packing often occurs in the field, rather than in a processing facility.In large operations, strawberries are cleaned by means of water streams and shaking conveyor belts.

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