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haploid set(medicine)
Haploid(medicine)
haploid(dictionary)
haploid number(medicine)
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Haploid (health)


A single set of chromosomes (half the full set of genetic material), present in the egg and sperm cells of animals and in the egg and pollen cells of plants. Human beings have 23 chromosomes in their reproductive cells.

Haploid: A set of chromosomes containing only one member of each chromosome pair. The sperm and egg are haploid and, in humans, have 23 chromosomes.

Haploids have one set of chromosomes (n=1), which is the same as a gamete (pollen or egg cell). Haploids can be distinguished from diploids (n=2) by using gene markers which are closely linked with the gene under study so they can be visually detected or by their physical characteristics. They are used in plant breeding to obtain pure lines that are homozygous by using colchicine to double the chromosome number, or by relying on spontaneous mutations.



A doubled haploid has two sets of chromosomes identical to the haploid and can form pollen and egg cells like a diploid plant, whereas, a haploid is rarely able to produce pollen for self fertilization .



Some examples of plants in which haploidy is used for breeding purposes are:



Cereals: wheat, barley, rye, oats, sorghum,rice and corn

Fibre:cotton

Forages: alfalfa and fescue

others: canola, tobacco and sunflowers

The success of tissue culture depends on many factors. Three important factors are the genotype of the donor plant and the conditions (photoperiod, light intensity and temperature) the plant was grown under, as well as the media used. To obtain a successful culture, the donor plant must be healthy and display vigorous growth.