distinguish Breeding back Backcrossing is a crossing of a Hybrid biology hybrid with one of its parent s or an individual genetically similar to its parent, in order to achieve offspring with a genetic identity which is closer to that of the parent. It is used in horticulture, animal breeding and in production of gene knockout organisms. Plants Advantages If the recurrent parent is an elite genotype , at the end of the backcrossing programme an elite genotype is recovered As there is no new Genetic recombination recombination , the elite combination is not lost Disadvantages Works poorly for quantitative trait s Is more restricted for recessive trait s In practice, sections of genome from the non recurrent parents are often still present and can have unwanted traits associated with them For very wide crosses, limited recombination may maintain thousands of alien genes within the elite cultivar Many backcrosses are required to produce a new cultivar which can take many years Natural backcrossings York radiate groundsel Senecio eboracensis is a naturally occurring hybrid species of Oxford ragwort Senecio squalidus and common groundsel Senecio vulgaris . It is thought to have arisen from a backcrossing of the F1 hybrid with S. vulgaris . ref cite journal title A new British species, Senecio eboracensis Asteraceae , another hybrid derivative of S. vulgaris L. and S. squalidae L url http www.watsonia.org.uk Vol24p375.pdf format PDF journal Watsonia last Abbot first R.J. coauthors Lowe, A.J. year 2003 volume 24 pages pp. 375 388 accessdate 2007 07 15 ref Again, the pure tall TT and pure ... cross have a phenotype ratio of 1 1. Animals Image Backcrossing mice from chimera.svg right 450px thumb This image demonstrates backcrossing of a heterozygous mouse from one genetic background onto another ... in the percentage of C57B 6J DNA that constitutes the genome of the offspring. Backcrossing may be deliberately ... backcrossing journal Genetics volume 170 issue 2 pages 909 17 year 2005 pmid 15802512 doi 10.1534 genetics.104.035451 ... more details
Orphan date February 2009 Unreferenced date December 2008 Inbred backcross lines IBLs in plant molecular biology are lineage evolution line s i.e. population s of plants derived from the repeated backcrossing of a Recombinant DNA recombinant line with the wild type , operating some kind of selection that can be phenotype phenotypical or through a molecular marker for the production of introgression line s . Category Molecular genetics genetics stub horticulture stub ... more details
Onesource date April 2009 In genetics , a test cross , first introduced by Gregor Mendel , is used to determine if an individual exhibiting a dominant trait is homozygous or heterozygous for that trait. More simply test crosses determine the genotype of an individual with a dominant phenotype. Test crosses involve breeding the individual in question with another individual that expresses a recessive version of the same trait. If all offspring display the dominant phenotype, the individual in question is homozygous dominant if the offspring display both dominant and recessive phenotypes, then the individual is heterozygous. In some sources, the test cross is defined as being a type of Backcrossing backcross between the recessive homozygote and F1 generation or F1 generation crossed with recessive parent is said to be a Test cross . If the individual being tested produces any recessive offspring except in cases of incomplete penetrance its genotype is heterozygous. If all the offspring are phenotypically dominant, its genotype is homozygous. References reflist refbegin cite book author Hopson, Janet L. John H. Postlethwait title Modern Biology publisher Holt Rinehart & Winston location Austin year 2008 pages isbn 0 03 036769 7 oclc doi accessdate refend Category Classical genetics genetics stub es Retrocruzamiento eu Atzeragurutzaketa fr Croisement de contr le it Reincrocio pl Krzy wka testowa pt Cruzamento teste ru tr Geri aprazlama ... more details
A hybrid swarm is a population of hybrid biology hybrid s that has survived beyond the initial hybrid generation, with interbreeding between hybrid individuals and backcrossing with its parent types. Such population are highly variable, with the genetic and phenetic characteristics of individuals ranging widely between the two parent types. Hybrid swarms thus blur the boundary between the parent taxa. Hybrid swarms occur when the hybrid is viable and at least as hybrid vigour vigorous as its parent types and there are no barriers to crossbreeding between the hybrid and parent types. Swarms cannot occur if one of these conditions is not met if the hybrid type has low viability, the hybrid population cannot maintain itself except by further hybridisation of the parent types, resulting in a hybrid population of low variability. On the other hand, if hybrids are vigorous but cannot backcross with parent populations, the result is a new hybrid taxon , which, aside from the contribution of new hybrids, evolves independently of its parent types. biology stub Category Hybridisation biology Category Population genetics cs Hybridn roj ... more details
italic title Taxobox name Cyathea boytelii status image image width image caption regnum Plant ae divisio Pteridophyta classis Pteridopsida ordo Cyatheales familia Cyatheaceae genus Cyathea subgenus Cyathea subg. Cyathea Cyathea sectio Cyathea sect. Alsophila Alsophila species C. boytelii binomial Cyathea boytelii binomial authority Caluff & Shelton synonyms Alsophila boytelii small Caluff & Shelton, 2002 small Cyathea boytelii is a Cyatheales tree fern endemic ecology endemic to the Sierra Maestra range of southeastern Cuba . It is a natural interspecific hybrid between Cyathea balanocarpa and Cyathea woodwardioides . The spores of C. boytelii are normal in appearance Caluff and Serrano 2002 suggest that it might therefore be fertile. This theory is strengthened by the presence of a large population of C. boytelii in the Gran Piedra area. Caluff and Serrano 2002 note that a full range of intermediates linking this hybrid with its parent species suggests the occurrence of backcrossing . The holotype type material was collected in Reserva Gran Piedra , Santiago de Cuba Province at an altitude of 1000 m on November 18, 1983. The specific epithet boytelii honours the late Fernando Boytel Jamb of Cuba. References Caluff, M. G. & G. S. Serrano 2002. Cuban novelties in the genus Alsophila Cyatheaceae . Willdenowia 32 303 309. ISSN 0511 9618 http www.ipni.org ipni plantsearch?id 325693 2&query type by id&output format object view&back page plantsearch&ret wholeName alsophila 20boytelii The International Plant Names Index Cyathea boytelii Category Cyathea Xboytelii Category Fern species Category Flora of Cuba ... more details
Taxobox image Crataegus laevigata x monogyna Blossom.jpg regnum Plant ae divisio flowering plant Magnoliophyta classis Magnoliopsida ordo Rosales familia Rosaceae genus Crataegus series Crataegus series Crataegus Crataegus ref Christensen, K.I. 1992 . Revision of Crataegus sect. Crataegus and nothosect. Crataeguineae Rosaceae Maloideae in the Old World. Systematic Botany Monographs . 35 1 199. ref species C. media binomial Crataegus media binomial authority Bechstein, Johann Matthaeus Bechst. DISPLAYTITLE Crataegus media Crataegus media , is a Hybrid biology hybrid between two species in the genus Crataegus Hawthorn , Crataegus monogyna C. monogyna and Crataegus laevigata C. laevigata , both in series botany series Crataegus series Crataegus Crataegus . Under the International Code of Botanical Nomenclature the name C. media covers all intermediate forms between the two parent species, including Backcrossing backcrosses . Horticulturally significant forms of C. media include some with double pink or red flowers, including Paul s scarlet and Rubra Plena ref Phipps, J.B., O Kennon, R.J., Lance, R.W. 2003 . Hawthorns and medlars . Royal Horticultural Society, Cambridge, U.K. ref . Images gallery Image Crataegus media rubra plena.jpg Flowers of the Rubra Plena cultivar of Crataegus media gallery References and external links references Category Crataegus media Category Hybrid plants az Crataegus media de Mittlerer Wei dorn ... more details
Taxobox regnum Plant ae divisio flowering plant Magnoliophyta classis Magnoliopsida ordo Rosales familia Rosaceae genus Crataegus series Crataegus series Crataegus Crataegus ref name KIC Christensen, K.I. 1992 . Revision of Crataegus sect. Crataegus and nothosect. Crataeguineae Rosaceae Maloideae in the Old World. Systematic Botany Monographs . 35 1 199. ref species C. macrocarpa binomial Crataegus macrocarpa binomial authority Johannes Jacob Hegetschweiler Hegetschw. synonyms synonyms include br C. eremitagensis Christen Christiansen Raunkiaer Raunk. ref name KIC br C. schumacheri Christen Christiansen Raunkiaer Raunk. ref name KIC br C. calycina Wilhelm Ludwig Petermann Peterm. ref name KIC DISPLAYTITLE Crataegus macrocarpa Crataegus macrocarpa , is a Hybrid biology hybrid between two species of Crataegus hawthorn Hawthorn , Crataegus monogyna C. monogyna and Crataegus rhipidophylla C. rhipidophylla , both in series botany series Crataegus series Crataegus Crataegus ref name KIC . It is sometimes confounded with Crataegus media C. media ref http www.habitas.org.uk flora species.asp?item 3431 Flora of Ireland information about C. media ref , the hybrid between Crataegus monogyna C. monogyna and Crataegus laevigata C. laevigata . Under the International Code of Botanical Nomenclature the name C. macrocarpa covers all intermediate forms between the two parent species, including Backcrossing backcrosses . References and external links references Ringl, A. Prinz, S. Huefner, A. Kurzmann, M. Kopp, B. 2007 . Chemosystematic value of flavonoids from Crataegus x macrocarpa Rosaceae with special emphasis on R and S Eriodictyol 7 O glucuronide and Luteolin 7 O glucuronide. Chemistry & Biodiversity . 4 2 154 162. http www3.interscience.wiley.com journal 114124260 abstract abstract available Category Crataegus macrocarpa Category Hybrid plants de Mittlerer Wei dorn ... more details
Introgression , also known as introgressive hybridization , in genetics particularly plant genetics , is the movement of a gene gene flow from one species into the gene pool of another by repeated backcrossing of an interspecific hybrid with one of its parent species. Purposeful introgression is a long term process it may take many hybrid generations before the backcrossing occurs. Introgression is an important source of genetic variation in natural populations and major cause of speciation in the sympatric mode. It can have important effects on the dynamics of hybrid zone s, speciation and adaptive radiation . ref name Grant Grant, P.R., Grant, B.R. & Petren, K. 2005 . Hybridization in the Recent Past . The American Naturalist 166 56 67. available online at http www.journals.uchicago.edu doi pdf 10.1086 430331 The American Naturalist ref There is evidence that introgression is a ubiquitous phenomenon in plants, in animals, ref Dowling, T. E. & Secor, C. L. 1997 . The role of hybridization and introgression in the diversification of animals. Annual Review Ecology and Systematics 28 593 619. ref ref Bullini, L. 1994. Origin and evolution of animal hybrid species. Trends in Ecology and Evolution 9 422 426. ref and even in humans, ref Holliday, T. W. 2003 . Species concepts, reticulations, and human evolution. Current Anthropology 44 653 673. ref where it may have introduced the microcephalin D allele. ref name 10.1073 pnas.0606966103 Cite journal doi 10.1073 pnas.0606966103 author Evans, Pd Mekel Bobrov, N Vallender, Ej Hudson, Rr Lahn, Bt title Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage journal Proceedings of the National Academy of Sciences of the United States of America volume 103 issue 48 pages 18178 83 year 2006 month Nov issn 0027 8424 pmid 17090677 pmc 1635020 url http www.pnas.org cgi pmidlookup?view long&pmid 17090677 ref Introgression differs from the simple hybridizatio ... more details
the year. It is also believed that the Pixies may be used to speed up backcrossing or pseudobackcrossing ... time in backcrossing, with special application to lettuce breeding. J. Amer. Soc. Hort. Sci. 110 ... more details
inappropriate tone date November 2009 DISPLAYTITLE Fragaria Comarum hybrids Taxobox name Fragaria Comarum hybrids image Pink Panda1 ies.jpg image width 240px image caption Fragaria x Comarum Pink Panda regnum Plant ae divisio Flowering plant Magnoliophyta classis Magnoliopsida ordo Rosales familia Rosaceae subfamilia Rosoideae There are several commercially important hybrids between Fragaria and Comarum species in existence, but they have not yet received formal botanical names as hybrids between those genera. Both Fragaria and Comarum have at different times been considered to be part of the genus Potentilla , and these hybrids have been named Potentilla x rosea ref name Mabberley David Mabberley D. J. Mabberley 2002. Potentilla and Fragaria Rosaceae reunited. Telopea 9 4 793 801. http www.rbgsyd.nsw.gov.au data assets pdf file 0019 72802 Tel9Mab793.pdf ref , or are sometimes referred to as Fragaria Potentilla hybrids . The first generation hybrids have been recorded as heptaploid ref name Mabberley , i.e. with seven sets of chromosomes four sets of chromosomes came from their octaploid strawberry parent, and three from their hexaploid Comarum parent ref name Mabberley . Commercial cultivars All commercial cultivars resemble strawberries more closely than they do Comarum . They are all vigorous, and produce runners profusely. The Pink Panda Strawberry , also known as Frel , is a patented Hybrid biology hybrid strawberry that is the result of crossing the Marsh Cinquefoil, Comarum palustre , and the Beach Strawberry , followed by backcrossing to strawberry. The plant is grown for ornamental purposes. It has pale pink flowers in contrast to the white flowers of naturally occurring strawberry species and it occasionally produces small strawberries. Franor marketed as Red Ruby Strawberry developed as a sport of Pink Panda , and features a more intense red color in the flowers. Gerald Straley is a seedling of Pink Panda , selected at Heronswood botanical garden Heronswo ... more details
disputed date January 2011 In genetics , two organism s that differ in one Locus genetics locus are defined as congenic ref cite web url http www.biology online.org dictionary Congenic title Congenic definition from Biology Online.org work Biology Online.org dictionary publisher http www.biology online.org dictionary Biology Online.org accessdate 2006 09 25 ref or coisogenic . Congenic strains Congenic strains are generated in the laboratory by mating two inbred strains usually rats or mice , and backcrossing the descendants 5 10 generations with one of the original strains, known as the recipient strain. Typically selection for either phenotype or genotype is performed prior to each backcross generation. In this manner either an interesting phenotype, or a defined chromosomal region assayed by genotype is passed from the donor strain onto an otherwise uniform recipient background. Congenic mice rats can then be compared to the pure recipient strain to determine whether they are phenotypically different if selection was for a genotypic region, or to identify the critical genetic locus, if selection was for a phenotype. Congenic strains are discussed in detail in Lee Silver s online book Mouse Genetics Concepts and Applications ref cite web url http www.informatics.jax.org silver frames frame3 3.shtml title Mouse Genetics Concepts and Applications work Lee Silver accessdate 2007 10 18 http www.informatics.jax.org silver frames frame3 3.shtml ref . Speed congenics can be produced in as little as 5 back cross generations ref cite journal author Markel P, Shu P, Ebeling C, et al. title Theoretical and empirical issues for marker assisted breeding of congenic mouse strains journal Nat. Genet. volume 17 issue 3 pages 280 4 year 1997 month November pmid 9354790 doi 10.1038 ng1197 280 url ref , through the selection at each generation of offspring that not only retain the desired chromosomal fragment, but that also lose the maximum amount of background genetic information f ... more details
species. Backcrossing of many generations of the hybrid Bekisar males with feral domestic game hens ... Green or Red Junglefowl, or by domestic fowl. This means that backcrossing would be a common mode ... successive generation of backcrossing, the odds of a fertile hybrid female increases. At a certain ... more details
distinguish Backcrossing Image Asdirewolf.jpg thumb 220px American Alsatian bred back to resemble the extinct Dire Wolf . Image Steppentarpan.jpg thumb 220px Heck horse in Hasel nne , Germany , 2004. Image with unknown copyright status removed Image NI4.JPG thumb 220px Bred back wolf called the Northern Inuit . deletable image caption 1 Monday, 4 August 2008 Image Tamaskan.jpg thumb 220px Bred back wolf called the tamaskan . Image Heck cattle male.jpg thumb 220px Bred back Aurochs bull Oostvaardersplassen , the Netherlands . Image Wild Pig KSC02pd0873.jpg thumb 220px Naturally bred back feral pig s razorback s in the USA, whose appearance resembles a wild boar . Breeding back can be described as either a natural or a human attempt to assemble or re assemble the genes of an extinct species, subspecies or domesticated breed, which may still be present in the larger gene pool of the overall species or those of multiple interbreedable species. Breeding back is controversial, especially claims that an extinct animal has been recreated. Similar appearance Phenotype phenotypical reconstruction does not assure similar behavior or biology. For some of the animals that are being bred back, questions remain about the ecological niche , hardiness, and disease resistance of the original creatures. For instance, the aurochs died out almost 400 years ago and the records kept cannot definitively answer some of these questions. Domestic examples In domestic animals, there are now several examples of breeding back. Dogs The American Alsatian dog breed has been created to resemble the bone and body structure of the Dire Wolf , although not the temperament. ref name Standards cite web url http shepaluteclub.tripod.com standards.html title Standards of the Breed publisher National American Alsatian Club accessdate 2010 11 05 month June year 2009 ref Other dog breeds that attempt to recreate a wolf look , without actually cross breeding with wolves, are the Tamaskan Dog , Utonagan , and the Northern ... more details
italic title taxobox name Encelia image Encelia farinosa form.jpg image caption Encelia farinosa regnum Plantae unranked divisio Angiosperms unranked classis Eudicots unranked ordo Asterids ordo Asterales familia Asteraceae tribus Heliantheae genus Encelia genus authority Michel Adanson Adans. subdivision ranks Species subdivision See text. Image CaliforniaSunflower.JPG right thumb Encelia californica Encelia is a genus of the Family biology plant family Asteraceae . It consists of shrub s and one geophyte of arid environments in southwestern North America and western South America . All have n 18 chromosomes. With the exception of the South American species, all are obligate Outcrossing outcrossers . In cultivation, the species readily form fertile F1 hybrid s, F2s, and backcrossing backcrosses , but in natural areas of sympatry , F2s and backcrosses are absent or rare. Encelia species are used as food plants by the larva e of some Lepidoptera species including the leaf miner Bucculatricidae Bucculatrix enceliae which feeds exclusively on Encelia farinosa . The phylogenetic sister group of Encelia is a clade comprising the genera Enceliopsis and Geraea . The three genera are informally called the Encelia alliance . Species Encelia actoni Adolph Daniel Edward Elmer Elmer Encelia asperifolia Sidney F. Blake S.F.Blake Curtis Clark C. Clark & Donald W. Kyhos Kyhos Encelia californica Thomas Nuttall Nutt. Encelia canescens Jean Baptiste Lamarck Lam. Encelia conspersa George Bentham Benth. Encelia densifolia Curtis Clark C. Clark & Donald W. Kyhos Kyhos Encelia farinosa John Torrey Torr. & Asa Gray A.Gray var. farinosa Brittlebush Encelia farinosa John Torrey Torr. & Asa Gray A.Gray var. phenicodonta Sidney F. Blake S.F.Blake Ivan Murray Johnston I.M.Johnston Encelia farinosa John Torrey Torr. & Asa Gray A.Gray var. radians Townshend Stith Brandegee T.S.Brandegee Encelia frutescens Asa Gray A.Gray ssp. frutescens Encelia frutescens Asa Gray A.Gray ssp. glandulosa Curtis ... more details
NOTOC Infobox Scientist name Li Zhensheng br image birth date birth date 1931 02 25 birth place Zibo , Shandong , China death date death place residence citizenship nationality China ethnicity Han Chinese field Genetics work institutions alma mater doctoral advisor doctoral students known for wheat breeding through distant hybridization author abbrev bot author abbrev zoo influences enhancing agricultural productivity and food security in China influenced prizes State Preeminent Science and Technology Award 2006 footnotes signature LZSsignature.jpg Li Zhensheng zh c Pinyin L Zh nsh ng born February 25, 1931 is a China Chinese geneticist . He mainly focuses on the study of the genetics of wheat . He is also an academician of the Chinese Academy of Sciences . Biography Mr. Li was born in Zibo , Shandong . In 1951, he graduated from Shandong Agricultural University . In an interview, he said that three scientists influenced him very much, they are Hua Luogeng for telling him how to learn , Qian Sanqiang how to do research and Ai Siqi Historical Materialism and Dialectical Materialism . ref http it.chinanews.cn it news 2007 02 27 880119.shtml ref Work In Li s scientific career, he has made three notable contributions to wheat genetics and breeding ref http www1.genetics.ac.cn xywwz news 09.htm Faculty Positions Bot generated title ref The series of new wheat cultivars Xiaoyan 4, 5, 6, 54 and 81 The wheat cultivars have greatly enhanced productivity of wheat. Among them, Xiaoyan 6 has been widely grown in China. Research on wheat chromosome engineering system This has enabled him to propose a creative methodology for producing wheat substitution lines through nullisomic backcrossing. The breeding and application of wheat varieties with high nutrient efficiency This kind of breeding needs less natural resources, and it protects the environment which is good for the sustainable development in Chinese agriculture. Awards and Honors ref http www1.genetics.ac ... more details
Orphan date March 2011 Perennial crops are crops developed to reduce inputs necessary to produce food. ref name Perennialization of crops ref name The Perennialization Project Perennials as a Pathway to Sustainable Agricultural Landscapes in the Upper Midwestern U.S. By greatly reducing the need to replant crops from year to year, perennial cropping can reduce topsoil losses due to erosion, ref name Erosion control increase biological carbon sequestration within the soil, and greatly reduce waterway pollution through pesticide and fertilizer runoff agricultural runoff . Mechanisms Erosion Control Because plant materials stems, crowns, etc. can remain in place year round, topsoil erosion due to wind and rainfall irrigation is reduced ref name Perennial crops and erosion control Water use efficiency Because these crops tend to be deeper and more fibrously rooted than their annual counterparts, they are able to hold onto soil moisture more efficiently, ref name Water use efficiency in perennial crops while filtering pollutants e.g. excess nitrogen traveling to groundwater sources. ref name Nitrate filtration in perennial strips Nutrient cycling efficiency Because perennials more efficiently take up nutrients as a result of their extensive root systems, ref name The Perennialization Project Perennials as a Pathway to Sustainable Agricultural Landscapes in the Upper Midwestern U.S. reduced amounts of nutrients need to be supplemented, ref name Increased Food and Ecosystem Security via Perennial Grains lowering production costs while reducing possible excess sources of fertilizer runoff . Example crops Perennial sunflower A perennial oil and seedcrop developed through backcrossing genes with wild sunflower. Perennial grain More extensive root systems allow for more efficient water and nutrient uptake, while reducing erosion due to rain and wind year round. Perennial rice Currently in the development stage using similar methods to those used in producing the perennialized ... more details
is backcrossing blight resistant American Chestnut Chinese Chestnut hybrids to American parents ... of backcrossing to create hybrids resistant to blight. Overall, it is anticipated that the species ... more details
, backcrossing . The progeny from that cross would then be tested for yield and mildew resistance and high ... yielding parent, the progeny will be crossed back to that parent for several generations See backcrossing .... In some instances markers for selection are removed by backcrossing with the parent plant prior to commercial ... more details
pp semi small yes Infobox Catbreed Put article text AFTER this infobox markup. See Wikipedia WikiProject Cats Templates for more info. name Sphynx image Sphinx2 July 2006.jpg imagecaption altname Canadian Hairless country Canada aacestd http www.aaceinc.org pages breeds sph.htm cfastd http www.cfainc.org breeds standards sphynx.html acfastd http www.acfacat.com sphynx standard.htm ticastd http tica.org public breeds sx intro.php ccastd http www.cca afc.com en BreedStandards sphynx.pdf acfstd gccfstd fifestd http www.fifeweb.org wp breeds std sph std.html otherstd notrecognized closed to out crossing stable numbers and nowhere near extinct note The Sphynx also known as Canadian Hairless is a rare cat breeds breed of cat known for its lack of a Coat animal coat . The contemporary breed of Sphynx known also as the Canadian Sphynx, distinct from the Russian Sphynx breeds Peterbald , Don Sphynx started in 1966, in Roncesvalles, Toronto when a hairless kitten named Prune was born. The kitten was mated with its mother backcrossing , which produced one more naked kitten. Together with a few naked kittens found later it became the primogenitor of the breed. The first sphynx breeders faced a number of problems The genetic pool was very limited breeders had rather vague ideas about sphynx genetics, and many kittens died. The naked male Epidermis born in 1975 to short haired mother provided new material to sphynx fanciers and new genes for further breed development. In the early stages of the breed crosses with devon rex were used, but later this crossing was frowned upon because it caused health problems. Now the Canadian Sphynx is a breed with a sound genetic pool. Outcrossing is still permitted using guidelines set down in the standards from each Feline Association around the globe. Characteristics File IW SGC Classicalcats Valentino.jpg thumb left 250px A Sphynx cat wearing a bandanna. The Sphynx appears to be a hairless cat, but it is not truly hairless. The skin texture r ... more details
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