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Polyploidy in Crop Plants
Concepts tested here
- Basic and haploid chromosome numbers
All Questions
2007 AIPMT-PRE 1 question
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In the hexaploid wheat, the haploid (n) and basic (x) numbers of chromosomes areThe basic number (x) is the number of chromosomes in one genome, i.e. one basic set. The haploid number (n) is the number of chromosomes in a gamete, which is half the somatic number.
Bread wheat (Triticum aestivum) is a hexaploid; its somatic cells contain six basic sets of chromosomes.
The basic number of wheat is x = 7.
Somatic chromosome number: 2n = 6x = 6 x 7 = 42.
Haploid (gametic) number: n = 42 / 2 = 21, which is equal to 3x.
So in hexaploid wheat n = 21 and x = 7.