Question

all back cross or not testcross but all testcross are back cross explain​

Answer 1

Here's your answer.....

In a back cross an individual from F1 generation is crossed with an individual similar to Parent plant.

And in a testcross an individual from F1 generation is crossed with a homozygous ,recessive individual (similar to F1 generation).

So that's why all backcross aren't testcross and vice versa.