Triticum aestivum , a hybrid formed by doubling of chromosomes, is...

$\textit{Triticum aestivum}$ (bread wheat) is an allohexaploid plant that originated through hybridization between different species followed by chromosome doubling (allopolyploidy).

Since this process of forming a new species occurs in the same geographical area as the parent species without any geographical isolation, it is a classic example of sympatric speciation.

Answer: Sympatric speciation