Common bread wheat (2n = 42) is

The common bread wheat that we use as our staple food is hexaploid. Root cells of wheat have 2n = 42 chromosome that is diploid chromosome number of 42 is six sets of the basic unit. And the basic unit can be obtained by dividing 42 by 6; $$\left( {\frac{{42}}{6} = 7} \right)$$   i.e. each set has 7 chromosomes.