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103-561: The garden strawberry (or simply strawberry ; Fragaria × ananassa ) is a widely grown hybrid species of the genus Fragaria in the rose family, Rosaceae , collectively known as the strawberries, which are cultivated worldwide for their fruit . This is appreciated for its aroma, bright red colour, juicy texture, and sweetness. It is eaten either fresh or in prepared foods such as jam , juice , pies , ice cream , milkshakes , and chocolates . Artificial strawberry flavourings and aromas are widely used in commercial products. Botanically,

206-475: A synthetic population . In horticulture , the term stable hybrid is used to describe an annual plant that, if grown and bred in a small monoculture free of external pollen (e.g., an air-filtered greenhouse) produces offspring that are "true to type" with respect to phenotype; i.e., a true-breeding organism. Hybridization can occur in the hybrid zones where the geographical ranges of species, subspecies, or distinct genetic lineages overlap. For example,

309-463: A bactrian camel and a dromedary . There are many examples of felid hybrids , including the liger . The oldest-known animal hybrid bred by humans is the kunga equid hybrid produced as a draft animal and status symbol 4,500 years ago in Umm el-Marra , present-day Syria . The first known instance of hybrid speciation in marine mammals was discovered in 2014. The clymene dolphin ( Stenella clymene )

412-564: A compost sock . Plants grown in compost socks have been shown to produce significantly more 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 study conducted by USDA confirms how compost plays a role in the bioactive qualities of two strawberry cultivars. Strawberries may be propagated by seed. Strawberries can be grown indoors in pots. Strawberries will not grow indoors in winter though an experiment using

515-584: A "dual-day length category". These plants are either long-short-day plants (LSDP) or short-long-day plants (SLDP). LSDPs flower after a series of long days followed by short days whereas SLDPs flower after a series of short days followed by long days. Each plant has a different length critical photoperiod, or critical night length. Many flowering plants (angiosperms) use a circadian rhythm together with photoreceptor protein , such as phytochrome or cryptochrome , to sense seasonal changes in night length, or photoperiod, which they take as signals to flower. In

618-564: A bear shot by a hunter in the Northwest Territories confirmed the existence of naturally occurring and fertile grizzly–polar bear hybrids . Hybridization between reproductively isolated species often results in hybrid offspring with lower fitness than either parental. However, hybrids are not, as might be expected, always intermediate between their parents (as if there were blending inheritance), but are sometimes stronger or perform better than either parental lineage or variety,

721-408: A broad spectrum of behaviors and physiology, including hibernation, seasonal migrations, and coat color changes. A prime example of the adaptation to photoperiods is the seasonal coat color (SCC) species. These animals undergo molting, transforming from dark summer fur to white coat in winter, that provides crucial camouflage in snowy environments. The view has been expressed that humans' seasonality

824-594: A chill snake lurks in the grass", and his imagery was taken up by medieval and early modern writers, the snake beneath the strawberry standing for dangerous literature, or beautiful but unfaithful women, or eventually any risky pleasure. In this vein, Shakespeare 's King Richard III asks for a dish of strawberries while feigning friendship to his enemy; while in Othello , Iago shows Desdemona 's handkerchief "spotted with strawberries", implying she has been unfaithful and hinting at Iago's own devious plans. The strawberry

927-419: A combination of blue and red LED lamps shows that this could be achieved in principle. In Florida , winter is the natural growing season and harvesting begins in mid-November. Nitrogen fertilizer is often needed at the beginning of every planting year. There are normally adequate levels of phosphorus and potash when fields have been fertilized for other crops in preceding years. To provide more organic matter,

1030-515: A considerable seed yield advantage over open pollinated varieties. Hybrid seed dominates the commercial maize seed market in the United States, Canada and many other major maize-producing countries. In a hybrid, any trait that falls outside the range of parental variation (and is thus not simply intermediate between its parents) is considered heterotic. Positive heterosis produces more robust hybrids, they might be stronger or bigger; while

1133-610: A cover crop of wheat or rye can be planted in the year before planting the strawberries. Strawberries prefer a somewhat acidic pH from 5.5 to 6.5, so lime is usually not required. To achieve top quality, berries are harvested at least every other day. The berries are picked with the caps and a section of the stem still attached. Strawberries need to remain on the plant until fully ripe, because they do not continue to ripen after being picked. The harvesting and cleaning process has not changed substantially over time. As they are delicate, strawberries are still often harvested by hand and packed in

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1236-509: A cross between a female horse and a male donkey, and the hinny, a cross between a female donkey and a male horse. Pairs of complementary types like the mule and hinny are called reciprocal hybrids. Polar bears and brown bears are another case of a hybridizing species pairs, and introgression among non-sister species of bears appears to have shaped the Ursidae family tree. Among many other mammal crosses are hybrid camels , crosses between

1339-509: A degree that none of the originally genetically distinct population remains. In agriculture and animal husbandry , the Green Revolution 's use of conventional hybridization increased yields by breeding high-yielding varieties . The replacement of locally indigenous breeds, compounded with unintentional cross-pollination and crossbreeding (genetic mixing), has reduced the gene pools of various wild and indigenous breeds resulting in

1442-407: A different organism is called a chimera . Hybrids are not always intermediates between their parents such as in blending inheritance (a now discredited theory in modern genetics by particulate inheritance ), but can show hybrid vigor , sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in

1545-602: A donkey as the father. A variety of mechanisms limit the success of hybridization, including the large genetic difference between most species. Barriers include morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization; others after it. In plants, some barriers to hybridization include blooming period differences, different pollinator vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and structural differences of

1648-493: A further subdivision, obligate photoperiodic plants absolutely require a long or short enough night before flowering, whereas facultative photoperiodic plants are more likely to flower under one condition. Phytochrome comes in two forms: P r and P fr . Red light (which is present during the day) converts phytochrome to its active form (P fr ) which then stimulates various processes such as germination, flowering or branching. In comparison, plants receive more far-red in

1751-548: A group of about 50 natural hybrids between Australian blacktip shark and the larger common blacktip shark was found by Australia's eastern coast in 2012. Russian sturgeon and American paddlefish were hybridized in captivity when sperm from the paddlefish and eggs from the sturgeon were combined, unexpectedly resulting in viable offspring. This hybrid is called a sturddlefish . The two genera Asymmetron and Branchiostoma are able to produce viable hybrid offspring, even if none have lived into adulthood so far, despite

1854-439: A long time, both intentionally for purposes such as biological control , and unintentionally, as with accidental escapes of individuals. Introductions can drastically affect populations, including through hybridization. There is a kind of continuum with three semi-distinct categories dealing with anthropogenic hybridization: hybridization without introgression, hybridization with widespread introgression (backcrossing with one of

1957-450: A long-day plant can flower if exposed to more red-light in the middle of the night. Cryptochromes are another type of photoreceptor that is important in photoperiodism. Cryptochromes absorb blue light and UV-A. Cryptochromes entrain the circadian clock to light. It has been found that both cryptochrome and phytochrome abundance relies on light and the amount of cryptochrome can change depending on day-length. This shows how important both of

2060-467: A longer cropping season and more fruit. During the Green Revolution of the 1950s, agronomists used selective breeding to expand phenotypic diversity of the garden strawberry. Adoption of perpetual flowering hybrids not sensitive to changes in photoperiod gave higher yields and enabled production in California to expand. The phylogeny of the cultivated strawberry within the genus Fragaria of

2163-498: A mate among the species that raised it, instead of the species of its biological parents. Cagebird breeders sometimes breed bird hybrids known as mules between species of finch , such as goldfinch × canary . Among amphibians, Japanese giant salamanders and Chinese giant salamanders have created hybrids that threaten the survival of Japanese giant salamanders because of competition for similar resources in Japan. Among fish,

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2266-432: A phenomenon called heterosis, hybrid vigour, or heterozygote advantage . This is most common with plant hybrids. A transgressive phenotype is a phenotype that displays more extreme characteristics than either of the parent lines. Plant breeders use several techniques to produce hybrids, including line breeding and the formation of complex hybrids. An economically important example is hybrid maize (corn), which provides

2369-405: A species, such as between different breeds . Single cross hybrids result from the cross between two true-breeding organisms which produces an F1 hybrid (first filial generation). The cross between two different homozygous lines produces an F1 hybrid that is heterozygous ; having two alleles , one contributed by each parent and typically one is dominant and the other recessive . Typically,

2472-570: A species. Photoperiodism affects flowering by inducing the shoot to produce floral buds instead of leaves and lateral buds. Some short-day facultative plants are: Day-neutral plants, such as cucumbers , roses , tomatoes , and Ruderalis ( autoflowering cannabis ) do not initiate flowering based on photoperiodism. Instead, they may initiate flowering after attaining a certain overall developmental stage or age, or in response to alternative environmental stimuli, such as vernalisation (a period of low temperature). Daylength, and thus knowledge of

2575-476: A strawberry is an edible fruit. From a botanical point of view, it is not a berry but an aggregate accessory fruit, because the fleshy part is derived from the receptacle . Each apparent seed on the outside of the strawberry is actually an achene , a botanical fruit with a seed inside it. Raw strawberries are 91% water, 8% carbohydrates , 1% protein , and contain negligible fat (table). A reference amount of 100 grams (3.5 oz) supplies 33 kilocalories ,

2678-548: Is oral allergy syndrome , but symptoms may also mimic hay fever or include dermatitis or hives , and, in severe cases, may cause breathing problems. 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). White-fruited strawberry cultivars , lacking Fra a1, may be an option for strawberry allergy sufferers. They ripen but remain pale, appearing like immature berries. A virtually allergen-free cultivar named 'Sofar'

2781-577: Is a hybrid of two Atlantic species, the spinner and striped dolphins . In 2019, scientists confirmed that a skull found 30 years earlier was a hybrid between the beluga whale and narwhal , dubbed the narluga . Hybridization between species is common in birds. Hybrid birds are purposefully bred by humans, but hybridization is also common in the wild. Waterfowl have a particularly high incidence of hybridization, with at least 60% of species known to produce hybrids with another species. Among ducks , mallards widely hybridize with many other species, and

2884-407: Is a hybridization test widely used in genetics to determine whether two separately isolated mutants that have the same (or similar) phenotype are defective in the same gene or in different genes (see Complementation (genetics) article). If a hybrid organism containing the genomes of two different mutant parental organisms displays a wild type phenotype, it is ordinarily considered that

2987-571: Is a particularly common mechanism for speciation in plants, and is now known to be fundamental to the evolutionary history of plants. Plants frequently form polyploids , individuals with more than two copies of each chromosome. Whole genome doubling has occurred repeatedly in plant evolution. When two plant species hybridize, the hybrid may double its chromosome count by incorporating the entire nuclear genome of both parents, resulting in offspring that are reproductively incompatible with either parent because of different chromosome counts. Human impact on

3090-466: Is a perennial system of matted rows or mounds which has been used in cold growing regions for many years. In some areas, greenhouses are used; in principle they could provide strawberries during the off season for field crops. In the plasticulture system, raised beds are covered with plastic to prevent weed growth and erosion. Plants are planted through holes punched in this covering. Irrigation tubing can be run underneath if necessary. Another method uses

3193-746: Is a rich source of vitamin C (65% of the Daily Value , DV), and a good source of manganese (17% DV), with no other micronutrients in significant content (table). Strawberries contain a modest amount of essential unsaturated fatty acids in the achene (seed) oil. Garden strawberries contain diverse phytochemicals , including 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 . Although achenes comprise only about 1% of

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3296-659: Is also more occasionally done in the livestock and pet trades; some well-known wild × domestic hybrids are beefalo and wolfdogs . Human selective breeding of domesticated animals and plants has also resulted in the development of distinct breeds (usually called cultivars in reference to plants); crossbreeds between them (without any wild stock ) are sometimes also imprecisely referred to as "hybrids". Hybrid humans existed in prehistory. For example, Neanderthals and anatomically modern humans are thought to have interbred as recently as 40,000 years ago. Mythological hybrids appear in human culture in forms as diverse as

3399-451: Is always sterile worker ants (and because ants are haplodiploid , unfertilized eggs become males). Without mating with males of the other species, the queens are unable to produce workers, and will fail to establish a colony of their own. Plant species hybridize more readily than animal species, and the resulting hybrids are fertile more often. Many plant species are the result of hybridization, combined with polyploidy , which duplicates

3502-600: Is available. Strawberries are often grouped according to their flowering habit. Traditionally in the Northern Hemisphere, 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. One plant throughout a season may produce 50 to 60 times or roughly once every three days. Strawberries occur in three basic flowering habits: short-day, long-day, and day-neutral. These describe

3605-552: Is derived from Latin hybrida , used for crosses such as of a tame sow and a wild boar. The term came into popular use in English in the 19th century, though examples of its use have been found from the early 17th century. Conspicuous hybrids are popularly named with portmanteau words , starting in the 1920s with the breeding of tiger–lion hybrids ( liger and tigon ). From the point of view of animal and plant breeders, there are several kinds of hybrid formed from crosses within

3708-745: Is found in Italian, Flemish, and German art, and in English miniatures. In medieval depictions, the strawberry often appears in the Virgin Mary 's garden, while in the Madonna of the Strawberries , she is seated on a strawberry bed and garlanded with strawberry leaves. In the work of the late medieval painter Hieronymus Bosch , strawberries feature in The Garden of Earthly Delights amongst "frolicking male nudes". Fray Jose de Siguenza described

3811-440: Is largely believed to be evolutionary baggage . . Human birth rate varies throughout the year, and the peak month of births appears to vary by latitude. Seasonality in human birth rate appears to have largely decreased since the industrial revolution. Photoperiodism has also been demonstrated in other organisms besides plants and animals. The fungus Neurospora crassa as well as the dinoflagellate Lingulodinium polyedra and

3914-399: Is placed on sugars, acids, and volatile compounds, which improve the taste and fragrance of the ripe fruit. Esters , terpenes , and furans are the chemical compounds having the strongest relationships to strawberry flavour, sweetness and fragrance, with a total of 31 out of some 360 volatile compounds significantly correlated to desirable flavour and fragrance. In breeding strawberries for

4017-412: Is reversed in the southern hemisphere (i.e., longest day is 21 December and shortest day is 21 June). Some long-day obligate plants are: Some long-day facultative plants are: Short-day (also called long-night) plants flower when the night lengths exceed their critical photoperiod. They cannot flower under short nights or if a pulse of artificial light is shone on the plant for several minutes during

4120-427: Is that hybrid individuals can form a "bridge" transmitting potentially helpful genes from one species to another when the hybrid backcrosses with one of its parent species, a process called introgression . Hybrids can also cause speciation , either because the hybrids are genetically incompatible with their parents and not each other, or because the hybrids occupy a different niche than either parent. Hybridization

4223-515: Is the proper time to give up on a population that is becoming a hybrid swarm, or to try and save the still existing pure individuals. Once a population becomes a complete mixture, the goal becomes to conserve those hybrids to avoid their loss. Conservationists treat each case on its merits, depending on detecting hybrids within the population. It is nearly impossible to formulate a uniform hybridization policy, because hybridization can occur beneficially when it occurs "naturally", and when hybrid swarms are

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4326-653: The Minotaur , blends of animals, humans and mythical beasts such as centaurs and sphinxes , and the Nephilim of the Biblical apocrypha described as the wicked sons of fallen angels and attractive women. Hybridization between species plays an important role in evolution, though there is much debate about its significance. Roughly 25% of plants and 10% of animals are known to form hybrids with at least one other species. One example of an adaptive benefit to hybridization

4429-887: The Rosaceae family was determined by chloroplast genomics in 2021. The polyploidy (number of sets of chromosomes ) is shown as "2N" etc. by each species. Rosa and other genera [REDACTED] Potentilla (cinquefoils) [REDACTED] at least 11 other species F. viridis 2N (green strawberry) [REDACTED] F. orientalis 4N (eastern strawberry) [REDACTED] F. moschata 6N (musk strawberry) [REDACTED] F. mandshurica F. vesca ssp. vesca 2N (wild strawberry) [REDACTED] F. vesca ssp. bracteata 2N F. virginiana 8N (Virginia strawberry, parent species) [REDACTED] F. chiloensis 8N (Chilean strawberry, parent species) [REDACTED] F. x ananassa 8N (the hybrid garden strawberry) [REDACTED] In culinary terms,

4532-432: The canary depends on the photoperiod. In the spring, when the photoperiod increases (more daylight), the male canary's testes grow. As the testes grow, more androgens are secreted and song frequency increases. During autumn, when the photoperiod decreases (less daylight), the male canary's testes regress and androgen levels drop dramatically, resulting in decreased singing frequency. Not only is singing frequency dependent on

4635-446: The raspberry ) had become "traditional symbols of the mouth and female sexuality". Hybrid (biology) In biology , a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties , subspecies , species or genera through sexual reproduction . Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from

4738-472: The sea urchin Strongylocentrotus purpuratus (female) and the sand dollar Dendraster excentricus (male). When two distinct types of organisms breed with each other, the resulting hybrids typically have intermediate traits (e.g., one plant parent has red flowers, the other has white, and the hybrid, pink flowers). Commonly, hybrids also combine traits seen only separately in one parent or

4841-438: The "suture region". It is at these regions that the subspecies were formed. Other hybrid zones have formed between described species of plants and animals. From the point of view of genetics, several different kinds of hybrid can be distinguished. A genetic hybrid carries two different alleles of the same gene , where for instance one allele may code for a lighter coat colour than the other. A structural hybrid results from

4944-506: The F1 generation is also phenotypically homogeneous, producing offspring that are all similar to each other. Double cross hybrids result from the cross between two different F1 hybrids (i.e., there are four unrelated grandparents). Three-way cross hybrids result from the cross between an F1 hybrid and an inbred line. Triple cross hybrids result from the crossing of two different three-way cross hybrids. Top cross (or "topcross") hybrids result from

5047-578: The Keens Imperial cultivar from many hybrids, winning the Royal Horticultural Society 's Silver Cup. Both the names 'pine' and 'ananassa' meant "pineapple", for the fruit's flavour. Modern strawberries and both parent species are octoploid (8N, meaning they have 8 sets of 7 chromosomes ). The genome sequence of the garden strawberry was published in 2019. Further breeding in the following centuries produced varieties with

5150-545: The United Kingdom, strawberries and cream is a popular dessert at the Wimbledon tennis tournament. Desserts using strawberries include pavlova , fraisier , and strawberry shortcake . The Roman poet Ovid wrote that in the past Golden Age, people had lived on wild fruits such as mountain strawberries. Virgil wrote in his Eclogues that "Ye who cull flowers and low-growing strawberries, / Away from here lads;

5253-399: The brain. Photoperiod can affect insects at different life stages, serving as an environmental cue for physiological processes such as diapause induction and termination, and seasonal morphs. In the water strider Aquarius paludum , for instance, photoperiod conditions during nymphal development have been shown to trigger seasonal changes in wing frequency and also induce diapause, although

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5356-524: The butterfly Limenitis arthemis has two major subspecies in North America, L. a. arthemis (the white admiral) and L. a. astyanax (the red-spotted purple). The white admiral has a bright, white band on its wings, while the red-spotted purple has cooler blue-green shades. Hybridization occurs between a narrow area across New England, southern Ontario, and the Great Lakes,

5459-426: The chromosomes. A few animal species are the result of hybridization. The Lonicera fly is a natural hybrid. The American red wolf appears to be a hybrid of the gray wolf and the coyote , although its taxonomic status has been a subject of controversy. The European edible frog is a semi-permanent hybrid between pool frogs and marsh frogs ; its population requires the continued presence of at least one of

5562-547: The chromosomes. Chromosome duplication allows orderly meiosis and so viable seed can be produced. Plant hybrids are generally given names that include an "×" (not in italics), such as Platanus × hispanica for the London plane, a natural hybrid of P. orientalis (oriental plane) and P. occidentalis (American sycamore). The parent's names may be kept in their entirety, as seen in Prunus persica × Prunus americana , with

5665-494: The commercial market in the United States, the volatile compounds methyl anthranilate and gamma-decalactone , prominent in aromatic wild strawberries, are especially desired for their "sweet and fruity" aroma characteristics. As strawberry flavour and fragrance appeal to consumers, they are used widely in manufacturing, including foods, beverages, perfumes and cosmetics. Some people experience an anaphylactoid reaction to eating strawberries. The most common form of this reaction

5768-481: The common pheasant and hen golden pheasant ( Chrysolophus pictus ). Spurs are absent in hybrids of the former type, although present in both parents. Hybridization is greatly influenced by human impact on the environment, through effects such as habitat fragmentation and species introductions. Such impacts make it difficult to conserve the genetics of populations undergoing introgressive hybridization . Humans have introduced species worldwide to environments for

5871-400: The crossing of a top quality or pure-bred male and a lower quality female, intended to improve the quality of the offspring, on average. Population hybrids result from the crossing of plants or animals in one population with those of another population. These include interspecific hybrids or crosses between different breeds. In biology, the result of crossing of two populations is called

5974-426: 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. Strawberry cultivars vary widely in size, colour, flavour, shape, degree of fertility, season of ripening, liability to disease and constitution of plant. In 2022, world production of strawberries was 9.6   million tonnes , led by China with 35% of

6077-444: The developing embryo . Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes. A few animal species and many plant species, however, are the result of hybrid speciation , including important crop plants such as wheat , where

6180-407: The diverse Heliconius butterflies , but that is disputed. The two closely related harvester ant species Pogonomyrmex barbatus and Pogonomyrmex rugosus have evolved to depend on hybridization. When a queen fertilizes her eggs with sperm from males of her own species, the offspring is always new queens. And when she fertilizes the eggs with sperm from males of the other species, the offspring

6283-413: The doubling of chromosome sets, causing immediate genetic isolation. Hybridization may be important in speciation in some plant groups. However, homoploid hybrid speciation (not increasing the number of sets of chromosomes) may be rare: by 1997, only eight natural examples had been fully described. Experimental studies suggest that hybridization offers a rapid route to speciation, a prediction confirmed by

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6386-611: The environment has resulted in an increase in the interbreeding between regional species, and the proliferation of introduced species worldwide has also resulted in an increase in hybridization. This has been referred to as genetic pollution out of concern that it may threaten many species with extinction. Similarly, genetic erosion from monoculture in crop plants may be damaging the gene pools of many species for future breeding. The conservation impacts of hybridization between species are highly debated. While hybridization could potentially threaten rare species or lineages by "swamping"

6489-425: The ephemerality of earthly joys, or the benefit that blessed souls get from religion, or to allegorize death and resurrection; by the late 20th century, it had come to symbolize female sexuality. In Europe, until the 17th century cultivated plants were obtained by transplanting strawberries from the forests; the plants were propagated asexually by pegging down the runners , allowing them to root, and then separating

6592-429: The fact that early generation hybrids and ancient hybrid species have matching genomes, meaning that once hybridization has occurred, the new hybrid genome can remain stable. Many hybrid zones are known where the ranges of two species meet, and hybrids are continually produced in great numbers. These hybrid zones are useful as biological model systems for studying the mechanisms of speciation. Recently DNA analysis of

6695-445: The female parent's name given first, or if not known, the parent's names given alphabetically. Photoperiodism Photoperiodism is the physiological reaction of organisms to the length of light or a dark period. It occurs in plants and animals . Plant photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light and dark periods. They are classified under three groups according to

6798-549: The field. Strawberries are popular in home gardens, and 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 : Around 200 species of pest arthropods attack strawberries. These include moths , fruit flies , chafers, strawberry root weevils, strawberry thrips, strawberry sap beetles, strawberry crown moth, mites , and aphids . Non-arthropod pests include slugs. Some are vectors of plant diseases; for instance,

6901-565: The fusion of gametes that have differing structure in at least one chromosome, as a result of structural abnormalities . A numerical hybrid results from the fusion of gametes having different haploid numbers of chromosomes . A permanent hybrid results when only the heterozygous genotype occurs, as in Oenothera lamarckiana , because all homozygous combinations are lethal. In the early history of genetics, Hugo de Vries supposed these were caused by mutation . Genetic complementation

7004-507: The genetic relationships between ducks are further complicated by the widespread gene flow between wild and domestic mallards. One of the most common interspecific hybrids in geese occurs between Greylag and Canada geese ( Anser anser x Branta canadensis ). One potential mechanism for the occurrence of hybrids in these geese is interspecific nest parasitism , where an egg is laid in the nest of another species to be raised by non-biological parents. The chick imprints upon and eventually seeks

7107-630: The genetically "pure" individuals with hybrids, hybridization could also save a rare lineage from extinction by introducing genetic diversity. It has been proposed that hybridization could be a useful tool to conserve biodiversity by allowing organisms to adapt, and that efforts to preserve the separateness of a "pure" lineage could harm conservation by lowering the organisms' genetic diversity and adaptive potential, particularly in species with low populations. While endangered species are often protected by law, hybrids are often excluded from protection, resulting in challenges to conservation. The term hybrid

7210-401: The hybrids are more fit and have breeding advantages over the indigenous ecotype or species. These hybridization events can result from the introduction of non-native genotypes by humans or through habitat modification, bringing previously isolated species into contact. Genetic mixing can be especially detrimental for rare species in isolated habitats, ultimately affecting the population to such

7313-407: The individual parentage. In genetics , attention is focused on the numbers of chromosomes . In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridization, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or

7416-563: The light input through the RHT and by innate circadian rhythms . This hormonal signal, combined with outputs from the SCN inform the rest of the body about the time of day, and the length of time that melatonin is secreted is how the time of year is perceived. Many mammals, particularly those inhabiting temperate and polar regions, exhibit a remarkable degree of seasonality in response to changes in daylight hours(photoperiod). This seasonality manifests in

7519-400: The loss of genetic diversity . Since the indigenous breeds are often well-adapted to local extremes in climate and have immunity to local pathogens, this can be a significant genetic erosion of the gene pool for future breeding. Therefore, commercial plant geneticists strive to breed "widely adapted" cultivars to counteract this tendency. Familiar examples of equid hybrids are the mule,

7622-478: The loss of leaves. Artificial lighting can be used to induce extra-long days. Long-day plants flower when the night length falls below their critical photoperiod. These plants typically flower during late spring or early summer as days are getting longer. In the northern hemisphere, the longest day of the year (summer solstice) is on or about 21 June. After that date, days grow shorter (i.e. nights grow longer) until 21 December (the winter solstice ). This situation

7725-597: The new plants. F. virginiana , the Virginia strawberry, was brought to Europe from eastern North America; F. chiloensis , the Chilean strawberry, was brought from Chile by Amédée-François Frézier in 1714. At first introduction to Europe, the Chilean strawberry plants grew vigorously, but produced no fruit. French gardeners in Brittany in the 1750s noticed that the Chilean plants bore only female flowers. They planted

7828-470: The night; they require a continuous period of darkness before floral development can begin. Natural nighttime light, such as moonlight or lightning, is not of sufficient brightness or duration to interrupt flowering. Short-day plants flower as days grow shorter (and nights grow longer) after September 21st in the northern hemisphere, which is during summer or fall. The length of the dark period required to induce flowering differs among species and varieties of

7931-452: The number of chromosomes has been doubled. A form of often intentional human-mediated hybridization is the crossing of wild and domesticated species. This is common in both traditional horticulture and modern agriculture ; many commercially useful fruits, flowers, garden herbs, and trees have been produced by hybridization. One such flower, Oenothera lamarckiana , was central to early genetics research into mutationism and polyploidy. It

8034-420: The only remaining evidence of prior species, they need to be conserved as well. Regionally developed ecotypes can be threatened with extinction when new alleles or genes are introduced that alter that ecotype. This is sometimes called genetic mixing. Hybridization and introgression, which can happen in natural and hybrid populations, of new genetic material can lead to the replacement of local genotypes if

8137-438: The other (e.g., a bird hybrid might combine the yellow head of one parent with the orange belly of the other). Interspecific hybrids are bred by mating individuals from two species, normally from within the same genus. The offspring display traits and characteristics of both parents, but are often sterile , preventing gene flow between the species. Sterility is often attributed to the different number of chromosomes between

8240-414: The painting as embodying the strawberry as a symbol of the ephemerality of earthly joys. Modern scholars have seen the symbolism entirely differently: Clement Wertheim-Aymes believed it meant the blessed souls' benefit from religion; Pater Gerlach supposed it meant spiritual love; and Laurinda Dixon asserted it was part of an allegory of death and resurrection. By the late 20th century, the strawberry (and

8343-573: The parent species), and hybrid swarms (highly variable populations with much interbreeding as well as backcrossing with the parent species). Depending on where a population falls along this continuum, the management plans for that population will change. Hybridization is currently an area of great discussion within wildlife management and habitat management. Global climate change is creating other changes such as difference in population distributions which are indirect causes for an increase in anthropogenic hybridization. Conservationists disagree on when

8446-537: The parent species. Cave paintings indicate that the European bison is a natural hybrid of the aurochs and the steppe bison . Plant hybridization is more commonplace compared to animal hybridization. Many crop species are hybrids, including notably the polyploid wheats : some have four sets of chromosomes (tetraploid) or six (hexaploid), while other wheat species have (like most eukaryotic organisms) two sets ( diploid ), so hybridization events likely involved

8549-506: The parents' common ancestor living tens of millions of years ago. Among insects, so-called killer bees were accidentally created during an attempt to breed a strain of bees that would both produce more honey and be better adapted to tropical conditions. It was done by crossing a European honey bee and an African bee . The Colias eurytheme and C. philodice butterflies have retained enough genetic compatibility to produce viable hybrid offspring. Hybrid speciation may have produced

8652-432: The photoperiod but the song repertoire is also. The long photoperiod of spring results in a greater song repertoire. Autumn's shorter photoperiod results in a reduction in song repertoire. These behavioral photoperiod changes in male canaries are caused by changes in the song center of the brain. As the photoperiod increases, the high vocal center (HVC) and the robust nucleus of the archistriatum (RA) increase in size. When

8755-429: The photoperiod decreases, these areas of the brain regress. In mammals, daylength is registered in the suprachiasmatic nucleus (SCN), which is informed by retinal light-sensitive ganglion cells , which are not involved in vision. The information travels through the retinohypothalamic tract (RHT). In most species the hormone melatonin is produced by the pineal gland only during the hours of darkness, influenced by

8858-454: The photoperiods: short-day plants, long-day plants, and day-neutral plants. In animals photoperiodism (sometimes called seasonality) is the suite of physiological changes that occur in response to changes in day length. This allows animals to respond to a temporally changing environment associated with changing seasons as the earth orbits the sun. In 1920, W. W. Garner and H. A. Allard published their discoveries on photoperiodism and felt it

8961-415: The photoreceptors are in regards to determining day-length. Modern biologists believe that it is the coincidence of the active forms of phytochrome or cryptochrome, created by light during the daytime, with the rhythms of the circadian clock that allows plants to measure the length of the night. Other than flowering, photoperiodism in plants includes the growth of stems or roots during certain seasons and

9064-637: The point of view of taxonomy , hybrids differ according to their parentage. Hybrids between different subspecies (such as between the dog and Eurasian wolf ) are called intra-specific hybrids. Interspecific hybrids are the offspring from interspecies mating ; these sometimes result in hybrid speciation. Intergeneric hybrids result from matings between different genera, such as between sheep and goats . Interfamilial hybrids, such as between chickens and guineafowl or pheasants , are reliably described but extremely rare. Interordinal hybrids (between different orders) are few, but have been engineered between

9167-460: The red-to far-red ratio in Arabidopsis can alter flowering. They discovered that plants tend to flower later when exposed to more red light, proving that red light is inhibitory to flowering. Other experiments have proven this by exposing plants to extra red-light in the middle of the night. A short-day plant will not flower if light is turned on for a few minutes in the middle of the night and

9270-423: The season of the year, is vital to many animals. A number of biological and behavioural changes are dependent on this knowledge. Together with temperature changes, photoperiod provokes changes in the color of fur and feathers, migration , entry into hibernation , sexual behaviour , and even the resizing of organs. In insects , sensitivity to photoperiod has been proven to be initiated by photoreceptors located in

9373-475: The shade, and this converts phytochrome from P fr to its inactive form, P r , inhibiting germination. This system of P fr to P r conversion allows the plant to sense when it is night and when it is day. P fr can also be converted back to P r by a process known as dark reversion, where long periods of darkness trigger the conversion of P fr . This is important in regards to plant flowering. Experiments by Halliday et al. showed that manipulations of

9476-998: The strawberry aphid, Chaetosiphon fragaefolii , can carry the strawberry mild yellow-edge virus . Strawberry plants are subject to many diseases, especially when subjected to stress. 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 ( Botrytis cinerea ), rhizopus rot, and leather rot. The NPR1 gene from Arabidopsis thaliana , AtNPR1 , confers A. thaliana ' s broad-spectrum resistance when transexpressed in F. ananassa . This includes resistance to anthracnose, powdery mildew, and angular leaf spot. A 1997 study found that many wound volatiles were effective against gray mold ( B. cinerea ). Both Tribute and Chandler varieties benefited from

9579-461: The strawberry is not a berry but an aggregate accessory fruit; each apparent 'seed' on the outside of the strawberry is actually an achene , a botanical fruit with a seed inside it. The garden strawberry was first bred in Brittany , France, in the 1750s via a cross of F. virginiana from eastern North America and F. chiloensis , which was brought from Chile by Amédée-François Frézier in 1714. Cultivars of F. × ananassa have replaced

9682-470: The term negative heterosis refers to weaker or smaller hybrids. Heterosis is common in both animal and plant hybrids. For example, hybrids between a lion and a tigress (" ligers ") are much larger than either of the two progenitors, while " tigons " (lioness × tiger) are smaller. Similarly, the hybrids between the common pheasant ( Phasianus colchicus ) and domestic fowl ( Gallus gallus ) are larger than either of their parents, as are those produced between

9785-451: The threshold critical day lengths for the determination of both traits diverged by about an hour. In Gerris buenoi , another water strider species, photoperiod has also been shown to be the cause of wing polyphenism , although the specific daylengths changed between species, suggesting that phenotypic plasticity in response to photoperiod has evolved even between relatively closely related species. The singing frequency of birds such as

9888-579: The total and the United States and Turkey as other significant producers. Due to the relatively fragile nature of the strawberry, approximately 35 percent of the $ 2.2   billion United States crop was spoiled in 2020. An Idaho company announced plans to launch more durable gene-edited strawberries. In the U.S., as of 2021, it cost growers around $ 35,000 per acre to plant and $ 35,000 per acre to harvest strawberries. For commercial production, plants can be propagated from bare root plants or plugs. One method of cultivation uses annual plasticulture ; another

9991-555: The total fresh weight of a strawberry, they contribute 11% of all polyphenols in the whole fruit; achene phytochemicals include ellagic acid , ellagic acid glycosides , and ellagitannins. Pelargonidin-3-glucoside is the major anthocyanin pigment in strawberries, giving them their red colour, with cyanidin-3-glucoside in smaller amounts. Strawberries also contain purple minor pigments, such as dimeric anthocyanins. Sweetness, fragrance and complex flavour are important attributes of strawberries. In plant breeding and farming, emphasis

10094-416: The treatments, although the effects vary widely with substance and variety. Strawberry plants metabolize these volatiles, more rapidly than do either blackberry or grape . Strawberries were eaten fresh with cream in the time of Thomas Wolsey in the court of King Henry VIII . Strawberries can be frozen or made into jam or preserves , as well as dried and used in prepared foods, such as cereal bars. In

10197-400: The two parental mutant organisms are defective in different genes. If the hybrid organism displays a distinctly mutant phenotype, the two mutant parental organisms are considered to be defective in the same gene. However, in some cases the hybrid organism may display a phenotype that is only weakly (or partially) wild-type, and this may reflect intragenic (interallelic) complementation. From

10300-462: The two species. For example, donkeys have 62 chromosomes , horses have 64 chromosomes, and mules or hinnies have 63 chromosomes. Mules, hinnies, and other normally sterile interspecific hybrids cannot produce viable gametes, because differences in chromosome structure prevent appropriate pairing and segregation during meiosis , meiosis is disrupted, and viable sperm and eggs are not formed. However, fertility in female mules has been reported with

10403-650: The wild woodland strawberry F. vesca among the Chilean plants to provide pollen; the Chilean strawberry plants then bore abundant fruits. In 1766, Antoine Nicolas Duchesne , in the gardens of the Palace of Versailles , France, found that F. ananassa was a hybrid of the recently arrived F. chiloensis and F. virginiana . In 1759, Philip Miller recorded the 'pine strawberry' ( F. ananassa ) in Chelsea, England . In 1806, also in England, Michael Keens of Isleworth selected

10506-531: The woodland strawberry F. vesca in commercial production. In 2022, world production of strawberries exceeded nine million tons, led by China with 35% of the total. Strawberries have appeared in literature and art from Roman times; Virgil wrote about the snake lurking beneath the strawberry, an image reinterpreted by later writers including Shakespeare . Strawberries appear in Italian, Flemish, and German paintings, including Hieronymus Bosch 's The Garden of Earthly Delights . It has been understood to symbolize

10609-430: Was the length of daylight that was critical, but it was later discovered that the length of the night was the controlling factor. Photoperiodic flowering plants are classified as long-day plants or short-day plants even though night is the critical factor because of the initial misunderstanding about daylight being the controlling factor. Along with long-day plants and short-day plants, there are plants that fall into

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