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In some situations, polyploid crops are preferred because they are sterile. For example, many seedless fruit varieties are seedless as a result of polyploidy. Such crops are propagated using asexual techniques, such as grafting. Polyploidy in crop plants is most commonly induced by treating seeds with the chemical colchicine.
The so-called Brassica triangle is an example of allopolyploidy, where three different parent species have hybridized in all possible pair combinations to produce three new species. [40] Polyploidy occurs commonly in plants, but rarely in animals.
An example would be the recent speciation of allopolyploid Spartina — S. anglica; the polyploid plant is so successful that it is listed as an invasive species in many regions. [ 24 ] Allopolyploidy and autopolyploidy
In Crepis and some other perennial plant species, a polyploid complex may arise where there are at least two genetically isolated diploid populations, in addition to auto- and allopolyploid derivatives that coexist and interbreed. Thus a complex network of interrelated forms may exist where the polyploid forms allow for intermediate forms ...
Several hypotheses have been proposed to explain the origin of Sequoia's polyploidy: allopolyploidy by hybridization between Metasequoia and some probably extinct taxodiaceous plant; Metasequoia and Sequoiadendron, or ancestors of the two genera, as the parental species of Sequoia; and autohexaploidy, autoallohexaploidy, or segmental ...
Hybrid speciation by spontaneous allopolyploidy. As Karpechenko realized, this process had created a new species, and it could justifiably be called a new genus, and proposed the name Raphanobrassica for them, but the earlier name Brassicoraphanus has priority. Plants of this parentage are now known as radicole. [4]
Sympatric speciation events are quite common in plants, which are prone to acquiring multiple homologous sets of chromosomes, resulting in polyploidy. The polyploid offspring occupy the same environment as the parent plants (hence sympatry), but are reproductively isolated.
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms.This number, along with the visual appearance of the chromosome, is known as the karyotype, [1] [2] [3] and can be found by looking at the chromosomes through a microscope.