Question

Hexaploid wheat developed through

• A. Monoclonal antibiodies
• B. Chromosome doubling
• C. Somatic hybridization
• D. Hybridization and doubling of chromosomes

Answer 1

Answer: (D)

Hybridization and doubling of chromosomes

Bread wheat is an allohexaploid (an allopolyploid with six sets of chromosomes, two sets from each of three different species). Free-threshing wheat is closely related to spelt. As with spelt, genes contributed from goatgrass (Aegilops tauschii) give bread wheat greater cold hardiness than most wheats, and it is cultivated throughout the world's temperate regions. Of the six sets of chromosomes, two come from Triticum urartu (einkorn wheat) and two from Aegilops speltoides. This hybridisation created the species Triticum turgidum, 580-820 thousand years ago. The last two sets of chromosomes came from Aegilops tauschii, 230-430 thousand years ago. So, hexaploid wheat is developed through hybridization and doubling of chromosomes. Thus, option D is correct.