In which one of the following combinations (1-4) of the number of chromosomes is the present day hexaploid wheat correctly represented ?

Options

A. `{:("Combination Monosomic","Haploid","Nullisomic","Trisomic"),(21,28,42,43):}`
B. `{:("Combination Monosomic","Haploid","Nullisomic","Trisomic"),(7,28,40,42):}`
C. `{:("Combination Monosomic","Haploid","Nullisomic","Trisomic"),(21,7,42,43):}`
D. `{:("Combination Monosomic","Haploid","Nullisomic","Trisomic"),(41,21,40,43):}`

Answer

d

Explanation

The present oday wheat is heaxaploid, knwn as trictical (2n=42) with 3 genomes A and B and D i.e, AABBDD. The 3 genomes are obtained from 3 different dploid species.
(i) Triticum aegilkopoids `-A A(2n=4)`
(ii) Aegilops speltroides `-BB(2n=14)`
(iii) Aegilops squarossa -DD(2n=14)
By crossing of first two diploids sps Trictricum dicoccoids (2n=28) i.e., tetraploid is produced AABB which an crossing with third species gives rise to Tricticum oestivuym (2n=42) hexaploid (AABBDD).
So its haploid set will have 21 chromosomes.
monosomic (2n-1) will have 41 chromosomes.
nullisomic (2n-2) will have 43 chromosomes,
and trisomic (2n+1)will have 43 chromosomes,