Why was it important that Mendel used truebred plants in his

Why was it important that Mendel used true-bred plants in his F1generation?

Solution

It was important that Mendel used true- bred or homozygous plants in F1 generation, so that he could easily see, what happens when they are crossed.

When Mendel observed that the alleles separate independently and give a mix of the alleles, he found out that plants could be heterozygous and would give different ratios in the F2 generation.