Zoology - Principles of Inheritance and Variation Question with Solution | TestHub

The present day wheat is hexaploid, known as triticale $(2n=42)$ with 3 genomes A, B and D i.e, $\mathrm{AABBDD}$. The 3 genomes are obtained from 3 different diploid species. (i) Triticum aegilopoides $-\mathrm{AA}(2\mathrm{n}=14)$ (ii) Aegilops speltoides - $\mathrm{BB}(2\mathrm{n}=14)$ (iii) Aegilops squarossa - DD $(2\mathrm{n}=14)$ By crossing of first two diploids sps Triticum dicoccoides $(2n=28)$ i.e., tetraploid is produced $\mathrm{AABB}$ which on crossing with third species gives rise to Triticum aestivum $(2\mathrm{n}=42)$ hexaploid (AABBDD). So its haploid set will have 21 chromosomes, monosomic ( $2n-1)$ will have 41 chromosomes, nullisomics $(2n-2)$ will have 40 chromosomes, and trisomic $(2n+1)$ will have 43 chromosomes.