Polyploid (1 Viewer)

Apr 9, 2021
In pearsons textbook it says that producing polyploid in plants causes it to become sterile yet it says it uses polyploidisation to make triticale hybrid plants fertile. Please explain? @Hivaclibtibcharkwa

In plants, a polyploid zygote often continues to develop into an adult plant that is sterile. A drawback of inducing polyploid in plants is that the seed crop produced by many polyploids is sterile or has lower fertility rates than their diploid types. ln some situations, polyploid crops are preferred because they are sterile.

After polyploidisation using the chemical colchicine, the triticale hybrid becomes fertile and can continue to sexually reproduce itself, usually by self-fertilisation


𝗕𝗶𝗼𝗹𝗼𝗴𝘆 𝗧𝘂𝘁𝗼𝗿
Jan 17, 2021
Polyploid individuals can arise in two ways. In autopoly- ploidy, all of the chromosomes come from a single species. This might happen, for example, due to an error in cell division that causes a doubling of chromosomes. Such individuals, termed tet raploids because they have four sets of chromosomes, can self- fertilize or mate with other tetraploids, but cannot mate and produce fertile offspring with normal diploids. The reason is that the tetraploid species produce “diploid” gametes that produce trip- loid offspring (having three sets of chromosomes) when combined with haploid gametes from normal diploids. Triploids are sterile because the odd number of chromosomes prevents proper pairing during meiosis.

A more common type of polyploid speciation is allopolyploidy, which may happen when two species hybridize. The resulting offspring, having one copy of the chromosomes of each species, is usually infertile because the chro- mosomes do not pair correctly in meiosis. However, such individu- als are often otherwise healthy. Sometimes, the chromosomes of such an individual spontaneously double, as just described for al- lopolyploidy. Consequently, the resulting tetraploid has two copies of each set of chromosomes and pairing during meiosis is no lon- ger a problem. As a result, such tetraploids are able to interbreed with other similar tetraploids, and a new species has been created.
It is estimated that about half of the approximately 260,000 species of plants have a polyploid episode in their history, includ- ing many of great commercial importance, such as bread wheat, cotton, tobacco, sugarcane, bananas, and potatoes. Speciation by polyploidy is also known to occur in a variety of animals, includ- ing insects, fish, and salamanders, although much more rarely than in plants.
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