Strawberries – Fragaria
Fragaria /frəˈɡɛəriə/ is a genus of flowering plants in the rose family, Rosaceae, commonly known as strawberries for their edible fruits. There are more than 20 described species and many hybrids and cultivars. The most common strawberries grown commercially are cultivars of the garden strawberry, a hybrid known as Fragaria × ananassa. Strawberries have a taste that varies by cultivar, and ranges from quite sweet to rather tart. Strawberries are an important commercial fruit crop, widely grown in all temperate regions of the world.
The strawberry is not, from a botanical point of view, a berry. Technically, it 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. Each apparent “seed” (achene) on the outside of the fruit is actually one of the ovaries of the flower, with a seed inside it.
Although it is commonly thought that strawberries get their name from straw being used as a mulch in cultivating the plants, the etymology of the word is possibly derived from “strewn berry” in reference to the fruit being “strewn” about the base of the plants.
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. 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.
There are more than 20 different Fragaria species worldwide. Numbers of other species have been proposed, some of which are now recognized as subspecies. Key to the classification of strawberry species is recognizing that they vary in the number of chromosomes. There are seven basic types of chromosomes that they all have in common. However, they exhibit different polyploidy. Some species are diploid, having two sets of the seven chromosomes (14 chromosomes total). Others are tetraploid (four sets, 28 chromosomes total), hexaploid (six sets, 42 chromosomes total), octoploid (eight sets, 56 chromosomes total), or decaploid (ten sets, 70 chromosomes total).
As a rough rule (with exceptions), strawberry species with more chromosomes tend to be more robust and produce larger plants with larger berries.
- Fragaria bucharica Losinsk. (China)
- Fragaria daltoniana J.Gay (Himalayas)
- Fragaria gracilis Losinskaja (China)
- Fragaria iinumae Makino (East Russia, Japan)
- Fragaria nilgerrensis Schlecht. ex J.Gay (South and Southeast Asia)
- Fragaria nipponica Makino (Japan)
- Fragaria nubicola Lindl. ex Lacaita (Himalayas)
- Fragaria pentaphylla Losinsk. (China)
- Fragaria rubicola
- Fragaria vesca L. – woodland strawberry (Northern Hemisphere)
- Fragaria viridis Duchesne (Europe, Central Asia)
- Fragaria yezoensis H.Hara (Northeast Asia)
- Fragaria x bifera Duchesne – (F. vesca × viridis). Europe
Octoploid species and hybrids
- Fragaria × ananassa Duchesne ex Rozier – Pineapple strawberry, Garden strawberry
- Fragaria chiloensis (L.) Mill. – Beach strawberry (Western Americas)
- Fragaria chiloensis subsp. chiloensis forma chiloensis
- Fragaria chiloensis subsp. chiloensis forma patagonica (Argentina, Chile)
- Fragaria chiloensis subsp. lucida (E. Vilm. ex Gay) Staudt (coast of British Columbia, Washington, Oregon, California)
- Fragaria chiloensis subsp. pacifica Staudt (coast of Alaska, British Columbia, Washington, Oregon, California)
- Fragaria chiloensis subsp. sandwicensis (Decne.) Staudt – ʻŌhelo papa (Hawaiʻi)
- Fragaria iturupensis Staudt – Iturup strawberry (Iturup, Kuril Islands)
- Fragaria virginiana Mill. – Virginia strawberry (North America)
Decaploid species and hybrids
- Fragaria cascadensis K.E. Hummer, Cascade Mountains in Oregon, United States
- Fragaria × Comarum hybrids
- Fragaria × vescana
been collecting berries every day
June 12 2017
Diseases and Problems
Around 200 species of pests are known to attack strawberries both directly and indirectly. These pests include slugs, moths, fruit flies, chafers, strawberry root weevils, strawberry thrips, strawberry sap beetles, strawberry crown moth, mites, aphids, and others. The caterpillars of a number of species of Lepidoptera feed on strawberry plants.
The amounts of pesticides required for industrial production of strawberries ( 300 pounds (140 kg) in California per acre) have led to the strawberry leading the list of EWG‘s “Dirty Dozen” of pesticide-contaminated produce.
Strawberry plants can fall victim to a number of diseases. 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. The crown and roots may fall victim to red stele, verticillium wilt, black root rot, and nematodes. The fruits are subject to damage from gray mold, rhizopus rot, and leather rot. To prevent root-rotting, strawberries should be planted every four to five years in a new bed, at a different site.
The plants can also develop disease from temperature extremes during winter. 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.
Propagation is by runners, which can be pegged down to encourage them to take root, 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. Strawberries may also be propagated by seed. 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.
Strawberry cultivars vary widely in size, color, flavor, shape, degree of fertility, season of ripening, liability to disease and constitution of plant. On average, a strawberry has about 200 seeds on its external membrane. 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, in general, 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. Greenhouses produce a small amount of strawberries during the off season.
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.
Manuring and harvesting
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 spreadings. The berries do not get washed until just before consumption. They are covered in a shallow pan and refrigerated when storing.
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 before planting the strawberries. Strawberries prefer a pH from 5.5 to 6.5 so lime is usually not applied.
|Nutritional value per 100 g (3.5 oz)|
|Energy||136 kJ (33 kcal)|
|Dietary fiber||2 g|
|Pantothenic acid (B5)||
|Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database
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.
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 that phytochemicals present in strawberries have anti-inflammatory or anticancer properties in laboratory studies. Epidemiological studies have associated strawberry consumption with lower rates of hypertension, inflammation, cancer, and death from cardiovascular diseases. Certain studies have suggested that strawberry consumption may have beneficial effects in humans such as lowering blood LDL cholesterol levels, total cholesterol, reducing the oxidation of LDL cholesterol, and decreasing the spike in blood sugar after high sugar meals and the spike in blood cholesterol seen after high-fat meals.
Garden strawberries contain the dimeric ellagitannin agrimoniin which is an isomer of sanguiin H-6. Other polyphenols present include flavonoids, such as anthocyanins, flavanols, flavonols and phenolic acids, such as hydroxybenzoic acid and hydroxycinnamic acid. Strawberries contain fisetin and possess higher levels of this flavonoid than other fruits.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, and ellagitannins.