Origin of Maize and Interaction With Teosintes
Teosintes are critical components of maize evolution, but opinions vary about which taxa were involved. According to the most widely-held evolutionary model, the crop was derived directly from Z. m. parviglumis by selection of key mutations; up to 12% of its genetic material came from Z. m. mexicana through introgression. Another model proposes that a tiny-eared wild maize was domesticated, and after being spread from east-central Mexico, this cultigen hybridized with Z. luxurians or Z. diploperennis resulting in a great explosion of maize genetic diversity, ear and kernel forms, and capacity to adapt to new habitats, as well as increased yields. A third model suggests that the early maize resulted from a cross between Z. diploperennis and a species of Tripsacum; support for this is minimal. A fourth model posits that teosinte resulted from hybridization between an early wild form of Z. m. mays and Tripsacum.
All but the Nicaraguan species of teosinte may grow in or very near corn fields, providing opportunities for introgression between teosinte and maize. First- and later-generation hybrids are often found in the fields, but the rate of gene exchange is quite low. Some populations of Z. m. mexicana display Vavilovian mimicry within cultivated maize fields, having evolved a maize-like form as a result of the farmers' selective weeding pressure. In some areas of Mexico, teosintes are regarded by maize farmers as a noxious weed, while in a few areas farmers regard it as a beneficial companion plant, and encourage its introgression into their maize.
Read more about this topic: Zea (genus)
Famous quotes containing the words origin of, origin, maize and/or interaction:
“Someone had literally run to earth
In an old cellar hole in a byroad
The origin of all the family there.
Thence they were sprung, so numerous a tribe
That now not all the houses left in town
Made shift to shelter them without the help
Of here and there a tent in grove and orchard.”
—Robert Frost (1874–1963)
“The real, then, is that which, sooner or later, information and reasoning would finally result in, and which is therefore independent of the vagaries of me and you. Thus, the very origin of the conception of reality shows that this conception essentially involves the notion of a COMMUNITY, without definite limits, and capable of a definite increase of knowledge.”
—Charles Sanders Peirce (1839–1914)
“O Love, what hours were thine and mine,
In lands of palm and southern pine;
In lands of palm, of orange-blossom,
Of olive, aloe, and maize and vine.”
—Alfred Tennyson (1809–1892)
“Just because multiples can turn to each other for companionship, and at times for comfort, don’t be fooled into thinking you’re not still vital to them. Don’t let or make multiples be parents as well as siblings to each other. . . . Parent interaction with infants and young children has everything to do with how those children develop on every level, including how they develop their identities.”
—Pamela Patrick Novotny (20th century)