Is money received from father taxable or not?

1. If father transfer his agricultural land 40 Lakh amount after sell (which is tax free) from his bank account  into son's bank account so will the son have to pay tax on that amount or not ?

2. Any Gift deed required for tax filling purpose ?

3.  Should the Gift deed be registered or not ? 

4. Even if there is a Will of the father, will there be a need for a gift deed?